Talk:Oxygen toxicity/Archive 1

Mechanism

Could any experts add some information about the mechanism of the intoxication? Or at least add something like "The mechanisms behind this is poorly understood"?--218.191.131.92 12:13, 29 May 2005 (UTC)

At normal pressure, breathing 100% Oxygen for more than an hour starts to cause chest pain and changes are seen in the Type 2 pneumocytes that line the alveoli. These are the cells that secrete surfactant and keep the alveoli open despite the tendency of Laplace’s law to close very small spaces. So the knock on effect is to get atelectasis,alveolar oedema and sometimes massive lung collapse. Over time the cells can accommodate their defences and if the need to breathe 100% is arrived at over a few days it is less toxic.

In ICU doctors like to get people down to 60% as soon as possible to avoid toxicity (having given 100% to preserve life) 100% can only be given via anaesthetic circuits not facemasks that entrain air. We frequently give 100% for tens of minutes at the start and finish of anaesthetics with no ill effect. All cells are subject to oxidative stress via oxygen radicals. Mechanisms such as Super oxide dismutase (SOD) and Glutathione mop up these radicals. High partial pressures drive the production of 02 radicals and toxicity results from this - cell membrane damage etc. The lungs are first in line to receive the damage Dissolved Nitrogen coming out of solution on decompression causes the 'bends'. Bubbles forming in the pulmonary circulation cause intractable coughing - 'the chokes' Oxygen in high concentration causes a number of different effects. At more than 2 bar the main problem is seizure activity. Hence the fact that you can't overcome the Bends by just breathing pure oxygen. The gas still needs to be diluted with something inert to avoid excess partial pressure -hence the use of Helium on deep dives that still need prolonged staged compression/decompression cycles.

Could anyone, even a non-expert, add to the "article" what Oxygen toxicity *is* ? The "article" says almost nothing about Oxygen toxicity beyond what is already conveyed by its title, but is especially notable for omitting a description of the symptoms. This makes the so-called article quite bizarre.71.224.204.167 03:33, 19 March 2006 (UTC)

It is quite important to note that the concept of oxygen toxicity in adult pulmonary and critical care medicine is a controversial one. In fact, there is significant debate as to whether or not patients with respiratory failrue breathing 100% oxygen at low altitudes (that is, breathing gas that is 100% oxygen at an altitude where the partial pressure of oxygen will be greater than 0.5 bar). In fact, oxygen toxicity has been called "the sasquatch of the adult ICU: often feared but never actually seen". —Preceding unsigned comment added by 140.142.205.49 (talk) 00:28, 2 November 2007 (UTC)

Good Article?

This article has been rated as "Start-class" since October 2007. Since then much revision and adding of references has been done - many thanks again to Gene Hobbs for his tireless work in referencing.

What more ought to be done to raise this to GA status? --RexxS (talk) 19:46, 2 June 2008 (UTC)

Ok - to answer my own question. I studied WP:GA? and considered the 6 criteria:

• 1. I've been through the article trying to wiki-link first occurrence of what may be considered jargon; rationalise the headings; remove non-wiki use of bold; and added a word that I thought was missing. Anything else anyone can spot?

• 2. Thanks to Gene, I believe it easily meets criteria for accuracy and verifiability.

• 3. I hope it fits what is required in breadth of coverage. Anything missing?

• 4. I'm pretty sure it is NPOV

• 5. This page shows a history of steady improvement and no content dispute. As of this year, it's been stable with mainly improvements to references as edits.

• 6. Here's the rub - no images! I'm not sure what images would be relevant to this topic and images are not required for GA, only preferable. Anybody have any ideas for images that would actually improve the content? --RexxS (talk) 21:42, 2 June 2008 (UTC)

Quick suggestions

Nice work so far! A couple quick suggestions:

• MoS recommends that headers not repeat the article title (so "Types", not "Types of oxygen toxicity".

• As for images, how about some chemical structures, e.g. for superoxide or unsaturated fatty acids?

• Looks like it could use a bit of a copyedit, e.g. putting all the punctuation before ref tags. Also, all jargon should be explained and the simplest possible terms should be used (it might be a little hard for a layperson to read). delldot talk 09:08, 12 June 2008 (UTC)

Thanks for the quick response - I wonder if you could give me some more advice on what I can forsee as the problems:

• The page has 163 links - do you know of any way of automating the checking process to make sure I don't break links by renaming a section (in case the section is linked to, I mean)?

• You mean other articles that may be linking to a section in this page? My instinct would be not to worry about it. If it breaks it'll just redirect to the article in general, and if anyone's paying attention to those pages they'll take care of it. delldot talk 18:40, 12 June 2008 (UTC)

• I like the idea of some images of chemical structures, although the fatty acid article already has several and the superoxide has one. Gene has told me he is likely to have some images of lungs damaged by chronic O2 toxicity which I think will go even better with this article. Is there such a thing as "too few" or "too many" images?

• Well you don't want to overwhelm the article with images, but I'd say one per section wouldn't be too much as long as they're good-sized sections. Gene's idea sounds fantastic, if s/he can provide a nice one it would make a great upper right image and improve the article a lot. I think if you end up needing to remove some you can safely do away with the chemical structures ones but you're not near to being in danger of that problem yet. delldot talk 18:40, 12 June 2008 (UTC)

• I'm happy to do some copyedits per MOS, but my problem is exemplified by the first sentence: There are 6 references which relate to that sentence - 2 of those are particular cites for "Paul Bert effect", 1 just for "Lorrain Smith effect" and 2 others illustrating the general point of high partial pressures. In other words, when a sentence contains 3 distinct points that are sourced, must I put all the sources at the end of the sentence? It seems (to me) more sensible in those cases to associate the relevant sources with the point that they verify, even though the punctuation they follow is not a period. Is there any way around this?

• Yeah, the problem with mid-sentence refs is annoying because they're ugly and kind of disruptive to the reading, but I'm definitely with you on that: the ref should come after the fact they're backing up. Otherwise it looks like they're endorsing something they never said, which I would say is a Very Bad Thing. So I'd have a preference for ugly mid-sentence refs over refs at the end (also I've been told in a peer review that you don't need a bunch of refs at the end of a sentence, you can just choose one or two of the best sources, e.g. a review paper from a respected journal). delldot talk 18:40, 12 June 2008 (UTC)

• I've been reading WP:PR and noticed that someone suggested it was acceptable to have the LEAD uncited as long as the points were cited in the main text. Perhaps that would be a sensible option here as the worst of the mid-sentence-refs occur in the lead (because of the very nature of summary, I guess)? --RexxS (talk) 02:09, 14 June 2008 (UTC)

• Would it be acceptable to everyone if we just moved the "also known as" portions of that sentence to the appropriate area in the article? If there are no complaints, I can do that anytime. Also, still no word from the Navy pathologist (he is moving) but I'll get the histology pictures up as soon as I have them. Thanks for all the hard work everyone, I am almost happy with this! --Gene Hobbs (talk) 02:51, 14 June 2008 (UTC)

• Although the LEAD is suggested as the usual place for "a.k.a.", I suspect this is intended to help people looking for that specific alias. In this case "Paul Bert effect" and "Lorrain Smith effect" are surely only of historical interest, so I would fully support the move, Gene. Go for it! --RexxS (talk) 01:02, 16 June 2008 (UTC)

• I moved the references but left the AKA's as they were because of their historical significance and occasional use in other literature. The references have been moved down and it does look much cleaner. If anyone else still wants to move the comments lower, feel free. Thanks again! --Gene Hobbs (talk) 03:34, 16 June 2008 (UTC)

I'll have a try at simplifying the jargon - I'm a diver, not a medic, so I will probably need to seek "medical advice" for that! Thanks in advance for anything you can shed some light on here --RexxS (talk) 18:05, 12 June 2008 (UTC)

I'm a layperson too, but with an interest in medicine, so I may be able to help out some. Let me know if you have any specific questions. Thanks for all your dilligent work! delldot talk 18:40, 12 June 2008 (UTC)

Image - Xray showing Kerley B lines

I went hunting for images to illustrate pulmonary oxygen toxicity and by following Pulmonary edema to Kerley B lines, I eventually managed to find some Xray images on the CDC site: this one and this one on this page.

I know the images are used in a discussion of HPS, but the Kerley lines are typical of the edema caused by OxTox, so would one of these be useful to illustrate the section 'Pulmonary oxygen toxicity'? If so, can we use images from CDC - a US Gov site? The images are marked "courtesy D. Loren Ketai, M.D", so we can acknowledge the source. Does anyone know if that is sufficient to use on WP? or do we need to get permission via OTRS? --RexxS (talk) 02:25, 20 June 2008 (UTC)

GA Review

The full text of the GA Review can be found here. Dr. Cash (talk) 19:04, 25 June 2008 (UTC)

Comments from delldot ∇.

I was asked for some comments, so here's a few to start. You can also review my recent copyedits to implement changes I've made throughout the article.

• also known to increase the formation of free-radicals - isn't superoxide a free radical? Maybe clarify the difference between ROS and free radicals here. delldot ∇. 04:50, 26 September 2008 (UTC)

To me it reads that ROS are formed and explains in more detail the superoxide radical. The page for ROS (general) and superoxide (specific) both discuss their formation so why should that be repeated here? (while not commenting on the quality of those articles.) --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

Sure, leave the detail to the main articles by all means. But do define your terms and make sure your reader is able to follow without having to leave your article to learn the meanings. I'm not talking about depth, just a parenthetical explanation. Look at pneumonia, for example: Frequently, it is described as lung parenchyma/alveolar inflammation and abnormal alveolar filling with fluid. The alveoli are microscopic air-filled sacs in the lungs responsible for absorbing oxygen. It defines its terms early on without rambling on or giving excessive detail.

• No mention is made in the mechanism section about how or why O2 causes the formation of these species. What property of O makes it do this? Also you could explain in one sentence how free radicals damage cell structures. delldot ∇. 04:50, 26 September 2008 (UTC)

again, I feel this is the job of the other articles. (complex topic, I can't do it in one sentence, anyone else?) --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

Maybe "free radicals, which have an unpaired electron, are strongly oxidizing and damage cell structures such as membranes by removing electrons from them" or some such, this is off the top of my head and would have to be checked for accuracy.

The bare oxygen radical O: has of course two unpaired electrons :p; Coupled with its small size, this gives it a huge electron affinity (=strongly oxidizing); Organic compounds containing double bonds have a "cloud" of electrons at that site and naturally the O: will react there. That's my understanding of the mechanism at the molecular level, but I'm still uncertain whether I can summarise that accurately enough or whether this article requires that detail of explanation. I'll have another look at the linked articles and have a think about it. Cheers --RexxS (talk) 17:19, 26 September 2008 (UTC)

Even normal molecular oxygen O₂ is a diradical with two unpaired electrons. It will attack hydrocarbons with multiple conjugated double bonds, to form hydroperoxides and a free-radical polymerization cascade. That happens when drying oils "dry"-- it's not really drying, but polymerizing. It happens so fast in paint thinner it spontaneously can catch fire-- no enzymes necessary. In cells those same fats (and even more sensitive ones like DHA, which is the most common in brain) are abundant. The only thing that keeps them from polymerizing is a lot of chain-terminating antioxidants like vitamin E. When the vitamin E runs out, your cell w-3 fatty acids polymerize. That's just ONE mechanism. BTW, the "tanning" of an animal's hide using the fats of the animal's own brain, is just this same process. :) SBHarris 03:11, 5 October 2008 (UTC)

• Consider changing Types to Classification. delldot ∇. 04:50, 26 September 2008 (UTC)  Done
• Very minor: You can now use pmc= with the PMC number in the template rather than the full url of a pubmed central resource. delldot ∇. 04:50, 26 September 2008 (UTC)

Cool, will try to get to these shortly. --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

• I find this sentence in the context it's used in to be dubious: It is believed that there is no long-term neurological damage from the seizure following removal of oxygen. I think it's being used in a much more general sense than the original (primary) source probably used it. This is a problem with primary sources in medical articles: you have to be careful to be clear that this is the finding of a specific study with specific parameters. The sentence now reads like seizures that result from this aren't harmful--I strongly doubt the authors of that paper would endorse that (although I haven't read it). Suggest removing it and reviewing other info from primary studies to make sure they're not overstating or overgeneralizing the findings. delldot ∇. 04:50, 26 September 2008 (UTC)

This is exactly how it is stated in both the review article referenced and the primary. (and the authors of both did not make changes when asked to review this article.) In both places it was opinion of the experts as no real data has or will be ever collected on long term follow-up. --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

Ok, sorry for the oversight on the review, don't know how I missed that. But the sentence is still out of context and makes the reader do a double take. Reading that paragraph, you get symptoms, onset, then "the seizure". What seizure? Is this the same as the convulsions mentioned in the symptoms sentence? Maybe rearrange to group these concepts if so. I still find it hard to believe that a seizure would always be harmless, as I understand it they aren't good for you. delldot ∇. 16:37, 26 September 2008 (UTC)

• Not related but also to do with that sentence, what is the seizure following removal of oxygen? What does it have to do with the article's subject? delldot ∇. 04:50, 26 September 2008 (UTC)

Treatment for toxicity is lowering the pO2 so removal from the high oxygen breathing gas. I will try to clarify later (Unless RexxS beats me to it) --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

It intended to say "following removal of oxygen, there is no damage from the seizure". I've re-writen that paragraph in an attempt to make it clearer and to emphasise Bitterman's conclusion, which really did find no evidence of long-term damage in any of the studies he summarised. See if you like it. --RexxS (talk) 15:50, 26 September 2008 (UTC)

When I first read it it wasn't clear whether the seizure had resulted from the original O2 overload or the removal of the O2. Maybe reword to show that removing the high concentration O2 is therapeutic and once that's done, seizures that resulted from the original overload are not found to be harmful. delldot ∇. 16:37, 26 September 2008 (UTC)

This is just a few to start out, I can add more if you're interested. delldot ∇. 04:50, 26 September 2008 (UTC)

Thanks, and please! --Gene Hobbs (talk) 12:52, 26 September 2008 (UTC)

I'd like to go back to my capitalision of "(see Nitric oxide, Peroxynitrite, and Trioxidane, etc.)", as in this diff since the MOS shows that when the reader is asked to view a named article - as in (see Article) - it always capitalises the name of the article per its naming rules. Good example are the last lines in WP:Mos#Wikilinks and WP:Manual_of_Style_(dates_and_numbers)#Precise_language. Unless you think that an exception should be made when the "(see ...)" is inline? Anyway, thanks again - all your efforts are much appreciated. --RexxS (talk) 15:50, 26 September 2008 (UTC)

Oh, sure, I see what you were doing now. Feel free to rv any changes I made you don't like. I've always had a vague preference for avoiding "see" (hence my change to "such as"), perhaps because it seems self-referencey? No problem though. delldot ∇. 16:37, 26 September 2008 (UTC)

More

• in the NOAA Diving Manual -- I recommend using the full name rather than (or with) the acronym on first mention, unless the acronym is already well known or no one ever uses the full name (like scuba). delldot ∇. 17:29, 26 September 2008 (UTC)
• Should "Oxygen Loading" really be capitalized? delldot ∇. 17:29, 26 September 2008 (UTC) Done
• Lvl 4 headings might be useful to break up the large sections under classification, e.g. symptoms, history, causes, prevention. delldot ∇. 17:29, 26 September 2008 (UTC)

• Funny, we were hit for the way we broke up sub-headings in the last GA review. This is what it looked like before the last re-format. Thanks again for the list!! (though I may not be able to get to anything again until tomorrow.) --Gene Hobbs (talk) 20:08, 26 September 2008 (UTC)

• Yeah, I this has to do with the organization problem I bring up in my last point here. I think my suggestion would fix that, but of course it would be a lot of work and you're going to end up with repetition either way. It's a tough choice. Anyway, take your time, let me know if you need anything from me. delldot ∇. 20:52, 26 September 2008 (UTC)

• The pulmonary section kind of launches in, maybe an introductory sentence would be good for transition. Something like "the lungs are also vulnerable to oxygen toxicity". delldot ∇. 17:29, 26 September 2008 (UTC)
• Give a date or date range for the sentence beginning "Lambertsen et al. made further discoveries..."; the first date in that para is 1899 and the next one is 1988, so the reader doesn't know when that took place. delldot ∇. 17:29, 26 September 2008 (UTC)
• In 1988, Hamilton et al. wrote procedures for NOAA to establish oxygen exposure limits for habitat operations. -- What are habitat operations? Define unfamiliar terms. delldot ∇. 17:29, 26 September 2008 (UTC)
• Pulmonary manifestations of oxygen toxicity are not the same for normobaric conditions as they are for hyperbaric conditions. - How do they differ? Maybe a few examples. delldot ∇. 17:29, 26 September 2008 (UTC)
• I would reverse the order of the para beginning In the treatment of decompression sickness, divers are exposed to long periods of oxygen breathing under hyperbaric conditions and the previous para--this would transition from the discussion of pressures into diving, and the statement "and pulmonary toxicity may occur" is kind of more introductory. You could also combine the diving-related paras; there are a lot of short choppy paras. delldot ∇. 17:29, 26 September 2008 (UTC)
• I think the last para under pulmonary is out of place. I don't like the "as noted earlier" since it adds wording without info (similar to the problems with "it should be noted" or "interestingly") and is self-referential. Additionally, it's a flag that you're revisiting something that's already been discussed. Why not integrate this material into the first mention? delldot ∇. 17:29, 26 September 2008 (UTC)
• Is it "High fraction oxygen" or "High-fraction oxygen"? delldot ∇. 17:29, 26 September 2008 (UTC)
• I'd like to see a prognosis section or more discussion of prognosis in each of the subsections; I didn't really get an idea of how serious the conditions were. Mortality and morbidity rates would be good. There could even be a discussion of increasing mortality with longer exposures and pressures. delldot ∇. 17:29, 26 September 2008 (UTC)
• Very minor points: Some journal titles in the refs have periods for abbreviations, some don't. Some author names have periods for first and middle initials, some don't. delldot ∇. 17:29, 26 September 2008 (UTC)
• I believe the "further reading" section is only for paper resources, no web stuff (which would go in "external links"). delldot ∇. 17:29, 26 September 2008 (UTC)
• Is the YouTube video to copyvio material? delldot ∇. 17:29, 26 September 2008 (UTC)
• I think you've done a good job with a difficult topic, it's not easy having to cover such different types in the same article. However, the article skips around a bit and revisits some topics a bunch of times (e.g. diving comes up again and again, some of it is repetitive because causes for CNS and pulmonary have features in common). It would take a lot of rearranging, but it might be worth it to reorganize with the introduction of the different types in a medium-sized classification section, and then further discussion on the different types below in separate "symptoms", "causes", "mechanism", "treatment", "prognosis", etc. sections. Either way, there's going to be splitting up and revisiting because you'll have to cover the different types in each section, but at least in my way you'll only have to discuss how the types differ; where they're the same it can be presented as general. Also, this way more info can be added without the subsections of classification (already large) getting ungainly. Lastly, you'll be able to bring it into compliance with MEDMOS, for what that's worth. I'm proposing a big reorganization, I know. Even if you can't bear to do this for the whole article, you can do it for parts. For example, you can take out the history paras from classification and combine them in a separate "history" section at the bottom. They really aren't that separate for the different types, as the repetition in the pulmonary section shows (Pulmonary oxygen toxicity was first described by Lorrain Smith in 1899 when he noted CNS toxicity and discovered..."). I also think taking out the discussion of partial pressures and hyper/normobaric conditions from the classification into its own section or under mechanism would help with the repetition and skipping around there. delldot ∇. 17:29, 26 September 2008 (UTC)

That's it from me, overall very well done! Let me know if I can offer any help or clarification. delldot ∇. 17:29, 26 September 2008 (UTC)

I've made an attempt at meeting the first 10 points. Given the mauling we had at the last GA review over breaking up the article too much, I'm reluctant to introduce further sub-headings. I've had a look at the criteria for GA and FA and thinking about your proposed re-write. At the moment, I'm leaning toward to the proposition that the principal breakdown of the article is now correct - i.e. into the three main areas of effect on the body (CNS, lungs, eye). Each of those three areas has different histories, mechanisms and consequences, as well as relating to different circumstances. There will be overlaps no matter how the article is organised, but in this case I think that by making a paragraph from each sub-topic (without explicitly giving them headings) to cover relevance to history, medical, diving, etc., it brings the article nearer to the goal of "brilliant prose". It's still a long way from that of course. Anyway, I'll try to do some copy-editing to reduce the small choppy paragraphs, but I need to look again with a fresh eye later! - Cheers --RexxS (talk) 21:51, 26 September 2008 (UTC)

A couple more points:

• According to MOS, journal titles should not be abbreviated ("this isn't a paper encyclopedia").
• The YouTube video comes from "Unified Team Diving" (UTD). They use YouTube to power the videos on their website and "andrewgeorgitsis" seems to be the owner and submitter to YouTube. However, the clip we are linking wasn't submitted by him and may indeed be a copyvio. I've emailed UTD to seek clarification or permission. If I don't get a fast response, I'll remove the link for safety.

I'll see what else I can do tomorrow. --RexxS (talk) 02:11, 27 September 2008 (UTC)

"Journal titles should not be abbreviated." Are you sure? Have a look at Template:Cite journal. "J. Clin. Invest." is used. Axl ¤ [Talk] 09:09, 27 September 2008 (UTC)

Yes, I'm absolutely sure. Have a look at WP:Scientific_citation_guidelines#Annotations, "Since Wikipedia is not a paper encyclopedia, references do not need to be as concise as they are in journals. In particular, it is always helpful to give the title of a journal article, and to give the complete name of the journal (Astrophysical Journal instead of Ap. J.)." Please let me know if I've misunderstood that section. Otherwise, I can only assume that the editor of the template entry you quoted was unaware of the guidelines for scientific citations (and I hope you'll agree that medical articles are scientific). --RexxS (talk) 14:32, 27 September 2008 (UTC)

Thanks for pointing out that guideline. Correcting this in our medical articles will be a major undertaking. [Perhaps a job for a bot?] Axl ¤ [Talk] 14:45, 27 September 2008 (UTC)

Ironically, several references within that guideline have abbreviated journal titles. Axl ¤ [Talk] 14:48, 27 September 2008 (UTC)

I suspect that many of the examples were written before consensus developed that full names would be helpful (and practical). I was also amused to see that juxtaposition. Anyway, I guess it's no big deal and at some point the kind of work a bot would do. For the moment, I'd suggest that persuading editors of the worth of the guideline would be most helpful - at least new and upcoming articles would have their refs written in full. --RexxS (talk) 15:13, 27 September 2008 (UTC)

GA Review

This review is transcluded from Talk:Oxygen toxicity/GA2. The edit link for this section can be used to add comments to the review.

I'm guessing that the writer/nominator is unaware of WP:MOSMED. The recommended style uses the following sections:-

• Classification
• Signs and symptoms or Characteristics
• Causes or Genetics
• Pathophysiology or Mechanism
• Diagnosis (including Characteristic biopsy findings and differential diagnosis)
• Prevention or Screening
• Treatment or Management
• Prognosis
• Epidemiology
• History (not patient history)
• Society and culture (e.g., stigma, economics, religious aspects, awareness, legal issues)
• Research directions
• In other animals
• See also (avoid if possible, use wikilinks in the main article)
• Notes
• References
• Further reading or Bibliography (paper resources such as books, not web sites)
• External links (avoid if possible)

Axl ¤ [Talk] 09:53, 27 September 2008 (UTC)

"Classification": Is it classified by the cause, or by the target organ damage?

"Signs and symptoms" is likely to be the bulk of the article, containing a description of the effects.

"Causes" should include risk factors such as diving depth/duration and prematurity of infants.

"Pathophysiology" should be a review of free radical formation and effects.

"Diagnosis": Presumably in diving it's a diagnosis of exclusion, in conjunction with the history? How are retinopathy and bronchopulmonary dysplasia diagnosed in infants?

"Prevention": Safety devices when diving. Monitoring and minimizing pO₂ for neonates?

"Treatment": although somewhat limited treatment options are available, this needs its own section with as much available info as possible.

"Prognosis": More missing information.

"Epidemiology": Frequency in divers? Frequency of retinopathy and BPD in premature neonates?

"History", "Society and culture", "Research" & "In other animals" are not required for GA status.

I am pleased to see that the current information is well-referenced. However there is a lot of missing information. Compliance with the recommended WP:MOSMED would help a lot. This article is not yet a good article. Axl ¤ [Talk] 10:14, 27 September 2008 (UTC)

Hyperoxia

I'm going to make a subpage called Hyperoxia and use the MOSMED headings with the comments from the GA review to give a template for copying the contents of Oxygen Toxicity into. We can make a decision later whether the name should be Hyperoxia or Oxygen toxicity (and which to redirect) and how to handle the move into article space later. Please feel free to edit it mercilessly --RexxS (talk) 15:19, 27 September 2008 (UTC)

That was a bit quicker than I thought. There's still mountains of cleanup to do, but that might be better in article space as it could attract more contributors. However, before I can move it into article space, we need to agree the article title. WP:MOSMED says "The article title should be the scientific or recognised medical name rather than the lay term." So that would suggest: "Hyperoxia" as the title; replace the existing redirect at Hyperoxia with the new page; merge the Oxygen toxicity page history into the new article page history. However, if we keep "Oxygen toxicity" as the article title, we only need to replace the existing page. As the consequences of a bold edit in this case may not be so easy to revert and discuss, I'd prefer to get some consensus before the move. --RexxS (talk) 17:17, 27 September 2008 (UTC)

That's a good start. I'll try to attract some interest from WikiProject Medicine. In my opinion, either title is fine. Axl ¤ [Talk] 17:32, 27 September 2008 (UTC)

I would think that hyperoxia is a specific disorder whereas oxygen toxicity is a wider mechanism involved in several conditions e.g. retinopathy of prematurity. I would suggest that anything specific to scuba diving and other hyperbaric oxygen toxicity is shifted away from this article, which perhaps should focus more on the broader field of oxygen toxicity (but not damage from reactive oxygen species specifically). Is there any agreement in ICD-10 on this? --Steven Fruitsmaak (Reply) 17:59, 27 September 2008 (UTC)

According to cancerweb medical dictionary, hyperoxia is "an excess of oxygen in the system, resulting from exposure to high oxygen concentrations, especially to hyperbaric pressures of oxygen." This definition does not imply toxicity, i.e. harmful effects. Axl ¤ [Talk] 19:36, 27 September 2008 (UTC)

Indeed, Hyperoxia is precisely a superabundance of oxygen in the system and it may have no effect (which isn't really of sufficient interest to make an encyclopedia article IMHO - but there is a definition in Wiktionary). It's when it causes an effect that it becomes notable. At present the wikipedia article Hyperoxia just redirects to Oxygen toxicity. I guess what Axl is saying is that "Oxygen toxicity" can stand as the article title? As for removing the diving-related and hyperbaric parts, I'm not sure. I'd be keen to see what was meant by the broader field of oxygen toxicity which didn't relate to damage from ROS, since I've found nothing in the literature to suggest anything broader. (edit: strike that - I remembered CO2 narcosis) Hyperbaric and diving medicine are just as much a part of medicine as - what would you call it? - clinical medicine. To reference the CNS, pulmonary and retinal effects in diving would need the same sources since it's pretty much the same disorder as when it occurs in non-diving related cases. I guess if the article became too big, I could see sense in splitting out part of it - but I don't think we're in any danger of that just yet. --RexxS (talk) 00:25, 28 September 2008 (UTC)

I am against splitting the two. Further comments on "clinical" vs. "diving": Non-hyperbaric medicine cases occur with Retinopathy of prematurity and normobaric pulmonary symptoms from the occasional ICU patients (controversial, see unsigned comment above). Hyperbaric medicine (HBO) sees pulmonary symptoms, CNS symptoms, and even more rarely Myopia following routine treatment protocols. Oddly enough, divers experience the same symptoms for the same reasons as the HBO patients. Both groups are coded the same way. A diver that shows up for treatment having shown these symptoms in the field are also identified with this code as well because the mechanisms are the same. In my view, just because it is a "health" risk from a recreational activity does not make it any less of a "clinical" problem. --Gene Hobbs (talk) 03:01, 28 September 2008 (UTC)

As for breaking this down into the MOSMED headings, why are the sections showing when they have not been written yet? Place holders? At least it looked clean and read smoothly before it was broken up. I think one day was NOT a long enough break for me on this article... Improving this has been a great discussion though and I have learned a ton about the format, thanks for the help! --Gene Hobbs (talk) 03:01, 28 September 2008 (UTC)

I was hoping that putting the sections in for a day or two might attract some more contributions. But I agree they are ugly and break up a clean article. They will either get fleshed out or we remove them soon. I must say though, looking at the content from the point of view of MOSMED is quite a refreshing discipline for me - I really didn't expect that. Anyway, we work at a pace that suits us: "There is no deadline". :) Best --RexxS (talk) 03:27, 28 September 2008 (UTC)

I'd probably say hyperoxia is the best suited title, considering our counterpart article is hypoxia. Nevermind, should have read the above properly. —Cyclonenim (talk · contribs · email) 21:54, 28 September 2008 (UTC)

A few useful refs

While looking for classifications, I found a few refs that might help fill out some of the other sections:

• The United States Naval Special Warfare Community uses oxygen tolerance testing to screen Navy combat swimmer candidates for sensitivity to the toxic effects of hyperbaric oxygen
• the following single-depth dive limits are proposed for 100% O2
• classification of OxTox and other stuff —Preceding unsigned comment added by RexxS (talk • contribs) 02:44, 28 September 2008 (UTC)

RexxS, You will find the first two full papers and several more here. Make sure if you use the first you also use the one showing why the US Navy NO LONGER does that test (also by Frank). That puts those squarely in the "history" section so some of the other sections will still be VERY bare. Other lists worth searching are here and here. The best source still ends up being the Bennett and Elliott text though. --Gene Hobbs (talk) 03:11, 28 September 2008 (UTC)

Thanks, as ever, for your wonderful knowledge of refs. I'll have a good read through after I get some sleep, which is why I threw those in here. The refs btw, just struck me - not because the USN did the testing but because they had some statistics in there and I wanted to get some ideas for "Epidemiology" --RexxS (talk) 03:31, 28 September 2008 (UTC)

"Epidemiology", of course... Frank's first paper was experimental but the last was a review of the tests. This one might be more along the lines of what you would want there from a USN standpoint though. For a more clinical HBO review, these might help: 1, 2, 3. I guess I should start thinking about how to address pulmonary toxicity mechanisms as well since we only really covered CNS so far... Thanks again! --Gene Hobbs (talk) 03:46, 28 September 2008 (UTC)

YouTube video

I contacted UTD to see what the status of that video was. The reply is as follows (I only snipped the routing & my email address to avoid spammers):

Message-Id: <[email protected]>
From: Unified Team Diving <[email protected]>
To: Rex Schneider <rexx@xxxxxxxxxxxxx>
In-Reply-To: <[email protected]>
Subject: Re: Unified Team Diving (UTD) International: Copyright?
Date: Sat, 27 Sep 2008 00:43:08 -0700
References: <[email protected]>
X-OriginalArrivalTime: 27 Sep 2008 07:43:12.0798 (UTC) FILETIME=[B1CBABE0:01C92074]


Rex

No problems to use it for educational purposes

andrew

On Sep 26, 2008, at 7:07 PM, Rex Schneider wrote:

> This is an enquiry e-mail via http://unifiedteamdiving.com from:
> Rex Schneider <rexx@xxxxxxxxxxxxx>
>
> There's a video on YouTube at http://uk.youtube.com/watch?v=BnzUoQ8ajJU
> which I believe belongs to UTD. However it was posted by
> "shayhazan" on July 5, 2007 and I can't determine if it is a
> copyright violation as your videos seem to be submitted by
> "andrewgeorgitsis". At present it is being used as an external link
> on Wikipedia http://en.wikipedia.org/wiki/Oxygen_toxicity and we are
> not allowed to link to copyvio material. Could you clarify for me
> the status of that YouTube video? or perhaps give permission for it
> to be linked from Wikipedia as it is a useful resource. Thanks in
> advance - RexxS


So the copyright owner is fine with it used for educational purposes. That's less than we would need to copy material into an article (we'd need GFDL), but I guess that's sufficient to allow us to link to the video on YouTube in this case as he seems to be content to let it stay there. Any other thoughts? --RexxS (talk) 20:36, 2 October 2008 (UTC)

Sounds ok. To make sure this doesn't get lost, might be better to forward to OTRS. --Steven Fruitsmaak (Reply) 21:26, 2 October 2008 (UTC)

Good idea, and great digging work RexxS! delldot ∇. 21:37, 2 October 2008 (UTC)

External links

As external links are discouraged (unless their content is useful and more detailed than appropriate for an encyclopedia article) I'm going to be WP:BOLD and remove the link to Scubadoc, as I don't think there's much there that's not contained either in the article or in its references. In addition, I am bothered by Scubadoc's assertion that "Convulsion at depth in water usually results in ... arterial gas embolism" - which I believe to be downright wrong (or at least totally unsupported). Please feel free to revert this and discuss here if I'm wrong. --RexxS (talk) 00:34, 13 October 2008 (UTC)

GA Review

This review is transcluded from Talk:Oxygen toxicity/GA3. The edit link for this section can be used to add comments to the review.

I am appalled by the image used. I guess it comes from the ignorance that bio students have to chemistry. Technically, this condition comes from breathing in dioxigen (i.e. O
₂) at high pressures, so the electron shell of the atom is not too relevant. Anyways, outside of this issue - which I prefer to be clarified throughout the article - the article is close to be a GA. I have placed some tags though. Also, please do not use references in the lead unless it is reall necessary - refs should be in the body of the article where the information in the lead is expanded. Nergaal (talk) 03:16, 19 October 2008 (UTC)

Added a few more tags. Common terms should be unlinked, while medical terms such as anxiety should be linked. Otherwise looks close. Nergaal (talk) 18:36, 20 October 2008 (UTC)

One more thing: what about relationship with "recreational" uses? I.e. likelihood of toxicity risks in recreational uses. Nergaal (talk) 18:40, 20 October 2008 (UTC)

I wish I could tell which links are common and which are medical (I thought "anxiety" was common!). Any other editors willing to cast an eye on this?

I've never heard of recreational oxygen breathing (apart from recreational scuba, of course), so that is worth researching, thanks. It's obvious (I hope) that it could never cause CNS toxicity - but pulmonary, hmmz - you could get maybe a couple of hours breathing pure O2 from a diving-size cylinder. You'd need a lot of cylinders to get close to pulmonary toxicity, but stranger things have happened. I'll do the research. --RexxS (talk) 19:59, 20 October 2008 (UTC)

Oxygen bar Nergaal (talk) 20:13, 20 October 2008 (UTC)

Hehe - yes I found that (and couldn't help doing an edit). I think I'd better head over there later and see if I can help. --RexxS (talk) 22:04, 20 October 2008 (UTC)

I've added a brief section on "Society and Culture" which could be expanded later, or (more productively) effort put in to improve Nitrox and Oxygen bar. --RexxS (talk) 20:12, 21 October 2008 (UTC)

GA suggestions

• The reference 73 is available as full text:[1]
• The lead section is normaly only a summary of the text and therefore needs no references.--Stone (talk) 19:09, 18 October 2008 (UTC)

Thanks very much for the link - I've incorporated it into ref name=Bert.

The lead is rather more than only a summary: it should serve as an introduction as well and also may require cited sources (see WP:LEADCITE). I do agree though that the lead is over-referenced. I'll try to simplify it a little - probably by moving the sentence with the list of affected tissues to "Classification", which discusses that in more depth. The references could be removed entirely from the lead, at the risk of editors asking for sources, but that should be decided by consensus - what do others think? --RexxS (talk) 20:00, 18 October 2008 (UTC)

Is there anything in the lead which might be chalanged? The refs 7 to 16 are only used in the lead is the info not also somewhere in the article?--Stone (talk) 20:16, 18 October 2008 (UTC)

I think I've fixed that - all 12 remaining refs in the lead now also appear in the body, so could be removed with little effort. I honestly can't judge what might be challenged - editors are a funny lot! --RexxS (talk) 20:25, 18 October 2008 (UTC)

• There are several abbreviations that that explained in one section and then used without explanation in another section. I believe few readers read all sections, but mostly dive into one somewhere in the middle. You should try to make sections stand on their own by writing out unusual abreviations (ppO2, ROP, BPD and ARDS). Narayanese (talk) 19:29, 19 October 2008 (UTC)

•  Done and thanks for pointing that out --RexxS (talk) 04:21, 21 October 2008 (UTC)

In depth review

• I am adding clarify and citation needed tags as I go through the article
• "as visual changes, ringing in the ears, nausea... dizziness" are linked to other articles. For example why visual changes links to tunnel vision? If it is the latter, then clearl4y specify it in the text - don't be vague.
• again, please unlink common terms - i.e. immersion, darkness, tickle, inhalation, cough, ambinet; but NOT ONLY THESE!
• "Signs and symptoms" lack the discussion on the ocular toxicity
• I would prefer expanding the causes for CNS one a bit
• I am still not happy with the image; do ou feel it is representative of the oxygen toxicity?
• please choose either SI or imperial units as primary ones; you use feet first, than later on grams - I would prefer SI

Once these are solved, I think this article can even go for a FAC after a good copyedit. Nergaal (talk) 00:26, 22 October 2008 (UTC)

Thanks again for your efforts in helping improve the article. I was particularly impressed by the way you grouped that bunch of references in "Classification"!

• Lead - to keep refs out of the lead, I've referenced the Bert & Smith effects under "History" - is a single ref ok? I can find more if you wish. I've rewritten the durations to give a little more precise timing (although the massive variability in onset makes precision difficult). I've re-written the third paragraph to eliminate the awkward grammar in the first sentence and to explain that (as you were hinting) it's only the pulmonary and ocular damage that is of concern with supplemental oxygen.

refs: fine. Nergaal (talk) 19:54, 22 October 2008 (UTC)

• Classification - the citation-needed you put in was sourced by the cite at the end of the next sentence (which is the source for both sentences). I've repeated the ref, but I thought that I didn't need to cite every sentence if the final citation covered all of them. --RexxS (talk) 16:11, 22 October 2008 (UTC)

it didn't seem that obvious but ok Nergaal (talk) 19:55, 22 October 2008 (UTC)

• "Visual changes" is sometimes referred to in the literature, rather than (the commoner) "tunnel vision" specifically, which leads me to suspect other visual effects may occur. I've re-written to try to avoid synthesis. But I might need guidance on that.

then ok, try saying "...visual changes (especially tunnel vision)..." Nergaal (talk) 20:03, 22 October 2008 (UTC)

• I've tried to unlink terms that I think are common, but retained "diver" (and similar) as they may be interesting links, rather than an explanation of the term, for the reader. I still think ambient requires definition: I've taught Scuba diving for almost 20 years now and experience suggests that all of my students who don't have a scientific background need to have "ambient pressure" explained to them - it's an important concept in Scuba as it's the sum of air pressure and water pressure at depth and has to be calculated regularly.

but wasn't it linked to the word "ambient"? link it to something relevant about pressure please Nergaal (talk) 20:03, 22 October 2008 (UTC)

Ah - there's the rub! It's a long story, but I tried to link to "ambient pressure" in Isobaric counterdiffusion only to find that the article didn't exist. So I linked to Ambient and Pressure. The Pressure article makes one brief mention of ambient pressure but doesn't explain it. Then the link to Ambient was reverted because it's a dab-page and "Ambient pressure" isn't one of the articles on the list. Finally I created the wikipedia article Ambient pressure but that's being moved to wikitionary as a dicdef. I would love to simply link to my definition on wiktionary (as it explains the term satisfactorily, imho) but it's been stuck in transwiki since August. Ok, it's a sore point and been a source of frustration. I guess I'll remove the link for the good of the article until the wiktionary definition arrives. —Preceding unsigned comment added by RexxS (talk • contribs) 22:39, 22 October 2008 (UTC)

• I've added a paragraph on signs of ROP - but it's usually skipped over in the literature I'm familiar with (as if it was obvious?).

ok

• I'm happier with the image than I was with the previous one - for what that's worth. I could suggest that the principal damage done by O2 toxicity results from that very reaction, so it is symbolic of the subject, but I'd love to find something that illustrated this whole complex subject.

how about generation of superoxide by interaction with iron II, or something like that, where dioxigen is the relevant initiator. Nergaal (talk) 20:03, 22 October 2008 (UTC)

• Units is a thorny problem. From a consistent, scientific point of view, I agree SI would be best throughout. Unfortunately, when considering the readership in the English-speaking world, I am aware that there exist big differences in the units used and they are often not SI units. To give an example: historically, the UK used feet and psi in the diving context - the USA still does. Nowadays, all UK divers work in metres and bars (and you won't find a Submersible Pressure Gauge marked in kPa anywhere!). But if I just use one unit, I reduce the understandability of the article to one group or the other. So for depth I chose to use metres preferentially (with feet in parentheses for USA readers). However, Donald did recommend a limit of "25 feet", not 7.6 metres. In that case, I reversed the standardisation I had used, since I think "Donald recommended limiting the depth breathing pure oxygen to 7.6 m (25 ft)" looks silly as well as being technically inaccurate. However, if you think standardisation of units is paramount, I'll change it. In the UK, the birth-weight of babies is always reported to layfolk in pounds and I would be surprised if that was different in the USA. Therefore, I've used parenthetical pounds to explain the 1,500 grams, etc. that is found in the literature. I'd be content to change that to 1.5 kg (3.3 lb) if you preferred, but I assumed from the literature that medical professionals use grams when referring to low birth-weight babies. For pressure, I've used "X bar (Y kPa)" throughout except for the mention of spaceflight where the literature uses psia - there I've displayed "X bar (Z psi)" in case the reader wanted to consult the reference and would then relate the partial pressure used in this article to those in the source. However, I wouldn't think the article loses much were I to remove the use of "(Z psi)" in that one case.

I don't care too much about the pressure units, but about the length/weight ones. I just think choosing a primary one is better. Anyways, check the instructions at wp:units. Nergaal (talk) 20:03, 22 October 2008 (UTC)

• I'm having a real problem in trying to cite "diagnosis by exclusion" for CNS toxicity. It is clearly what happens (absent epilepsy or hypoglycemia), but the problem of exclusion is that it's not a direct diagnosis. It's what you have left after eliminating other possibilities, so I can see that it's going to be harder to source. I'll drop a note into the doctor's mess and see if they can help. --RexxS (talk) 18:57, 22 October 2008 (UTC)

if no reference is abailable, perhaps try adding a text note? anyways, it is not that essential Nergaal (talk) 20:03, 22 October 2008 (UTC)

Nice progress with the article! The image now truly represents the article's topic! Although there is still 1 tag, I believe you will add it soon. One suggestion though: from an aesthetic point of view, there is such a thing as too many refs; in principle, if the statement is not disputable, is enough to have a single truly reliable reference, and discard the less relevant ones since they are redundant. Besides that, remember to do a bit more copyediting and then take a look at Wp:FAC. Nergaal (talk) 03:59, 24 October 2008 (UTC)

Prognosis: CNS Toxicity

Although Bitterman concluded that no long-term neurological effects have been observed following a seizure, I think that I've seen a reference somewhere to brain lesions in rats following prolonged exposure and repeated OxTox. I've just seen the "John Bean effect" referred to on a scuba forum and eventually tracked down:

• Bean JW. Effects of oxygen at increased pressure. Physiol Rev 25: 1-147, 1945

Does anyone know if this is refuted or is Bitterman's conclusion dependant on all incidents being managed by immediate reduction in ppO2? --RexxS (talk) 01:17, 20 October 2008 (UTC)

Oxygen "intoxication"

Hey guys, I created an article a long time ago called oxygen intoxication and I think I might have very well made a mistake and created an article for an already created article (i.e. this one here). If anyone wants to have a quick look at oxygen intoxication and double check if that and oxygen toxicity are indeed the same thing, then feel free to delete oxygen intoxication and make a straight redirect (again if you think it is applicable).

Kind regards.Calaka (talk) 05:18, 24 October 2008 (UTC)

I'm very much against deleting articles that someone has worked hard to reference, but it does seem that the content is pretty much covered in Oxygen toxicity. A redirect would work, but I wonder if anyone might also search for "oxygen intoxication" looking for a reference to "oxygen narcosis"? Perhaps it would best serve the encyclopedia as a disambiguation page with links to both Oxygen toxicity and narcosis? --RexxS (talk) 16:04, 24 October 2008 (UTC)

Calaka, thanks for pointing this out. I agree that "Oxygen intoxication" should be changed to redirect to "Oxygen toxicity". Axl ¤ [Talk] 16:02, 26 October 2008 (UTC)

Hey all, sorry for the slow reply (real life is extremelly hectic - hence my large decrease in wikipedia editing) but just wanted to say that I am fine with whatever you all decided on doing. I have no problem with a redirect to this article and if there is any extra information in oxygen intoxication that is not covered in oxygen toxicity can also be added here (plus the references can be utilised if required). Although having said that, I have no problem with a disambiguation page being made either. But I guess that would assume there is a link between oxygen intoxication and oxygen narcosis (which I am no expert in knowing).

Regards.Calaka (talk) 13:28, 7 November 2008 (UTC)

Comments on article

Are all the names in the introduction really the same thing, or could some be listed as similar without cluttering up the intro with a zillion bolded terms? I search for Paul Bert effect and Lorrain Smith effect, and neither redirects here. Who uses these terms? Why do they exist? It seems to me these alternate names can be redirected to this article without being mentioned, or be mentioned without being in bold and without being in the intro paragraph.

What is the difference between oxygen toxicity and hyperoxia?

What is HBOT? ChildofMidnight (talk) 17:06, 23 November 2008 (UTC)

Moving forward with article reconstruction

Sorry about that. Let me explain myself, and then I'm okay with a reversion if I'm in the wrong. The introduction had a lot parenthesis and a lot of terminology in bold. I've discussed my questions and isses with that in the above "comments on article section" so I await answers that will resolve the issue better for me. Is the Paul Bert and the other thing synonymous with oxygen toxicity or with hyperoxia?

Then the other thing was that I wasn't sectioning the intro but moving the detailed descriptions of central nervous system damage to another more appropriate (I think) section. The intro was a bit detailed in parts and doesn't include anything about 1)signs and symptoms 2)mechanism 3)diagnosis 4)history

So I think a bit summarizing those sections would be a better fit.

Finally the causes section of the article has a lot of redundancies with other sections and should probably be combined elsewhere (to the section discussing the 3 types of oxygen toxicity?). ChildofMidnight (talk) 17:18, 23 November 2008 (UTC)

Yes, they are the historical names and both may be found older literature. Google for the exact terms - a few hundred hits, but you'd expect that since they became less common before the internet was invented. It's not a question of redirects - it's about having terms that may be text searched via the wp search box. Try not to link bold terms like hyperoxia (WP:Lead) - better to link the next occurrence. Paul Bert first discovered the CNS effect and J Lorrain Smith the chronic (see History). Hyperoxia is simply an excess of oxygen, which may or may not be causing the effects described; when it is causing these effects, it's then referred to as the condition of 'Oxygen toxicity'. As the non-effect level of hyperoxia isn't notable (it's just a dicdef), it doesn't deserve an article to itself: hence the redirect. Good point about HBOT - it's HyperBaric Oxygen Therapy.

Try it this way: read the whole article (the sections, btw are mandated by MOSMED); then look at how best to summarise them into no more than 4 paragraphs (Lead), making sure that the first sentence indicates "what it is" & "why it is notable/of interest" and the first para puts that in context. You've then got no more than 3 paras to summarise the key points of all the other sections of the article. I never said it was easy :p - but your fresh input helps us all to see how we can improve the article. Don't worry - there's no deadline. Cheers --RexxS (talk) 17:36, 23 November 2008 (UTC)

I suggest creating redirects for the Bert and Smith names. They can be mentioned (non-bold) as historical names that were once used for this malady. Anyone searching those terms will find an article on the condition they're looking for, (as well as see them mentioned in the introduction) but I don't think they have to be bolded terms in the intro. The reason it was called this could also be included. The whole point of the redirects would be to address the "having terms that may be text searched via the wp search box" issue so I'm confused about your objection.

If hyperoxia isn't the same thing it shouldn't be bold, but I think it should be wikilinked on its first appearance. Did you have other issues with any of the changes?ChildofMidnight (talk) 18:40, 23 November 2008 (UTC)

The redirects are a good idea and I'll make them. Nevertheless, the wp search allows for searching for text within articles as well as titles and WP:LEAD says "If the subject of the page has a common abbreviation or more than one name, the abbreviation (in parenthesis) and each additional name should be in boldface on its first appearance." As I understand it, if someone searches for a subject, but arrives at an article with a different name, the bolded terms immediately show that the article is actually about the subject they searched for. 'Hypoxia' and 'Oxygen toxicity' are loosely interchangeable, the distinction being rather too small to allow a different article, so I suggest it ought to be considered an alternative name. I have read: "Use as few links as possible before and in the bolded title. Thereafter, words used in a title may be linked to provide more detail." to indicate that links in bolded text are undesirable (with the monobook skin, it's often hard for me to spot that it's both) to imply that you bold the first occurrence and link the second - but that's just my reading, and your interpretation is just as likely to be right as mine.

Anyway have another look at the lead and see if it fits this: "The lead should be able to stand alone as a concise overview of the article. It should establish context, explain why the subject is interesting or notable, and summarize the most important points—including any notable controversies that may exist." Cheers --RexxS (talk) 22:46, 23 November 2008 (UTC)

Oxygen intoxication

What does oxygen intoxication have to do with this article? Is this one more phrase that should be added? ChildofMidnight (talk) 07:45, 26 November 2008 (UTC)

I'm afraid so. The exact phrase "oxygen intoxication" gets about 1,300 ghits (compared with 771 for "oxygen toxicity syndrome") - all the ones I checked referred to oxygen toxicity (usually the pulmonary form). I'll try an edit and see how it looks. --RexxS (talk) 13:42, 26 November 2008 (UTC)

Oxygen toxicity

Have done a quick review of this article. Could use better organization with each section on prevention divided into the situation. Prevention in a HBOT chamber involves making sure the patient does not have a fever, underlying seizure disorder etc well prevention well diving is completely different. Needs more subheading.--Doc James (talk · contribs · email) 20:56, 31 March 2009 (UTC)

Thanks for that. I've made subheadings in "Prevention" in a way that seemed logical to me, but other suggestions are welcome. The original article had many subheadings and was criticised at GAC for that, so I'm not keen to break it down any more than necessary. If you think other specific sections need subheadings, please let me know. I think that it is also common to test for hypoglycemia before routine HBOT, but I'll have to search for a cite. If you know any good sources on HBOT, I'd be glad to hear of them - as you probably realise, I'm a diver, not a medic. --RexxS (talk) 23:22, 31 March 2009 (UTC)

Sure when I get home will look into it. I see oxygen toxicity on a regular basis in HBOT but rarely is it of any clinical significance.--Doc James (talk · contribs · email) 03:25, 1 April 2009 (UTC)

Oxygen toxicity in space

I did not think oxygen toxicity would be a problem in space. It is not the percentage of oxygen that matter but the partial pressure. Therefore with commercial diving at 500 m 5 % oxygen can kill you. 51 ATM * 0.05 = 2.5ATM of Oxygen But in Space at a partial pressure of 0.3 ATM even 100% oxygen forever would have no effect as this would be the same as 0.3 ATM of oxygen.--Doc James (talk · contribs · email) 03:30, 1 April 2009 (UTC)

What you do get in space flight is the bends as you body is no longer exposed to pressure and thus nitrogen that you might have breathed before take off would come out of solution in you blood forming bubbles. This is why you breath 100% oxygen before take off to wash out nitro.--Doc James (talk · contribs · email) 03:31, 1 April 2009 (UTC)

You stating the obvious for a reason or just for fun? The Webb et. al. reference listed in the article clearly shows that O2 toxicity is not a concern for modern pre-breathe protocols. There has been concern over this in the past since majority of pre-breathing was breathing 100% O2 on the surface (14.7 psia) or at a 10.2 psia stage for an extended period of time. So, what do you want us to do with your comments? Thanks. --Gene Hobbs (talk) 03:59, 1 April 2009 (UTC)

I think Doc is just trying to be helpful - and I did invite comments <g>. The problem in space is a little more complicated than that. The space shuttles and International Space Station maintain an atmosphere very close to that on Earth (1 atm, 21/79 mix), but can't do that for space suits when EVA (a space walk) is required. So the suits are pressurised to 4.3 psia (0.3 ata) on 100% oxygen and that's where the danger of DCI occurs. If the suit were instead pressurised to 9.5 psia (0.65 ata) using oxygen, then the risk of DCI would be much reduced, but the possibility of pulmonary toxicity needs to be considered. The ref to Webb et al that sources that paragraph is a trial done to determine that risk over five eight-hour simulated EVAs. --RexxS (talk) 04:14, 1 April 2009 (UTC)

My point is not that pulmonary toxicity is not risk, it's that the work has been done to show that it is not a factor in current EVA work. Jim's work was using an old protocol that required a ton more oxygen than is required in the current pre-breathe reduction protocol. If toxicity was not shown in his EVA's (Which did require a decompression that was VERY long at that time), it would not be shown in the current protocols utilizing significantly less oxygen. In fact, pulmonary toxicity was not seen much at all though it is a known risk. (The risk is why I kept it in the article when I did the major re-write right before your brilliant work.) We have had tenders for the current research that have had some minor pulmonary symptoms (I am one of them) but that is looked at as an occupational hazard of using an old decompression protocol with a known DCS risk. Pulmonary toxicity is not tracked in any way for us (nor is our DCS). So I am back to my question, what can we change? It must be fairly unclear at this time or we would not be having this conversation. --Gene Hobbs (talk) 16:41, 1 April 2009 (UTC)

Hehe - I think this is nature's way of telling us this specific topic needs an article on its own. Risk assessment of extra-vehicular activities anyone? --RexxS (talk) 16:57, 1 April 2009 (UTC)

There are two publications being written now that summarize the work involved in the prebreathe reduction protocol as NASA has moved away from the old procedures (In Phase 5 now). Gernhardt and Pollock are working on them now but I know their time has been pretty tight. So, good idea! --Gene Hobbs (talk) 17:16, 1 April 2009 (UTC)

Image of scleral buckle

This images really needs to be improved.--Doc James (talk · contribs · email) 18:13, 2 April 2009 (UTC)

Yes, you're right, Doc. I made a simplified "cartoon" based on this, but I know I have little artistic ability. I'll see if I can find someone to create a better looking image (as I haven't been able to find a PD photo so far). --RexxS (talk) 01:03, 3 May 2009 (UTC)

Infobox image

The image used in an infobox on an article like this normally illustrates the condition. The use of Dr. Bert's image here seems inappropriate. Perhaps the image in the History section would be more useful? --Una Smith (talk) 22:20, 7 May 2009 (UTC)

Thanks so much for that suggestion. It has been a continual problem in trying to find an image that illustrates or provides an overview of the condition, probably because of the rarity and unpredictability of the onset of CNS symptoms. Ruhrfisch made a similar criticism at WP:Peer review/Oxygen toxicity/archive1, but I've not been able to find the picture of the dog in tonic seizure anywhere. I'll switch the images now (and try to improve the caption). --RexxS (talk) 01:35, 8 May 2009 (UTC)

Superoxide

The superoxide ion is not very reactive (see PMID 11732335 or PMID 7592468) and will not directly oxidise lipids. Instead this species is probably more important as a source of more reactive ROS, such as the hydroxyl radical. Tim Vickers (talk) 04:52, 8 May 2009 (UTC)

Also, I don't think free metals are a significant reductant for oxygen, this reaction is probably more commonly performed by enzymes such as flavoenzymes. See PMID 14527285 for a good review on this topic. Tim Vickers (talk) 05:00, 8 May 2009 (UTC)

I've rewritten to clarify the role of *OH as an initiator of lipid peroxidation. I agree that the section about "certain metals" was confused; I've rewritten to try to clarify that reduction of ferric ions is a use the body makes of superoxide, rather than the previous implication that Fe3+ would serve to control levels of ROS. Hope that section reads better to you now. --RexxS (talk) 14:21, 8 May 2009 (UTC)

Thanks for your skill in rewording that section, Tim. I'm no expert, but I thought the evidence currently at ref 77 was pretty compelling as regards superoxide-dependent iron uptake. Nevertheless, I'm only too happy to be guided by you on this - it is most gratifying to see highly experienced editors helping to improve the article. --RexxS (talk) 19:08, 8 May 2009 (UTC)

It might very well be true, and it looks quite a solid paper, but it hasn't been generally accepted yet, or independently replicated, and hasn't made it into any of the reviews I've read on the topic. It is certainly a possible role, but it is still a bit new and uncertain to put in a summary section such as yours. This caught my eye in particular as the "classic" interaction of superoxide with redox-active metals is as a reductant in the fenton reaction, so increasing ROS rather than doing anything useful. Tim Vickers (talk) 19:14, 8 May 2009 (UTC)

Lifting an oxtox victim

I was uncomfortable with the recent insertion of "...however, the diver must not be raised during the seizure itself, because his unpredictable breathing may result in arterial gas embolism" as it may be observed that a slow enough ascent will not produce AGE solely as a result of seizure, as long as the casualty is breathing. However, there seems to be a received wisdom that it is not safe to lift a victim during seizure. This may be due to fear of compromising the safety of the rescuer, or of the consequences of a mismanaged ascent (made more difficult by convulsions). US Navy says "If depth control is possible and the gas supply is secure (helmet or full face mask), the diver should be kept at depth until the convulsion subsides and normal breathing resumes. If an ascent must take place, it should be done as slowly as possible to reduce the risk of an arterial gas embolism. A diver surfacing unconscious because of an oxygen convulsion must be treated as if suffering from arterial gas embolism. Arterial gas embolism cannot be ruled out in an unconscious diver." U.S. Navy Diving Manual, 6th revision. US Naval Sea Systems Command. 2006. volume 1, chapter 3, page 45.

My own very strong opinion is that an unconscious diver needs to be on the surface out of the water ... the belief that a convulsing diver must be held underwater until the convulsion has passed is a misconception and possibly a dangerous one ... The airway is not spasmed shut during the clonic (jerking) phase of a convulsion ... the mere fact that patients can survive 30 minutes in status epilepticus tells us the same thing ... there are some nice animal studies that reveal a degree of inspiratory obstruction during seizures, but no expiratory obstruction ... It follows that the clonic phase of a seizure may be a good time to bring a diver to the surface. The airway is open, but they are not breathing ... Expanding gas during the ascent will tend to keep water out of the airway. So long as it can escape it should do no harm. Waiting until the end of a seizure when respiration resumes with an unprotected airway may be the wrong thing to do.

Dr Simon Mitchell, January 2008

So US Navy was wary of AGE in 2006 and before. However, Gene points out "I would offer that this is still up for debate and might be best presented as such. Simon Mitchell's thoughts (UHMS diving committee chairman): http://www.rebreatherworld.com/rebreather-accidents-incidents/16705-standardizing-ccr-rescue-skills-3.html#post163661" - quite a compelling argument to lift during the clonic phase. Consensus does change in diving practice, but keeping track of it in secondary sources can be difficult. I think I'd like to expand this section outlining both views, if I can find Simon Mitchell's recommendations somewhere outside a forum post because WP:RS would require it to be directly attributed as his opinion, thus contrasting inequitably with USN Dive Manual. I'll start looking, but I think it's just the sort of challenge that Gene does so well! --RexxS (talk) 19:16, 26 May 2009 (UTC)

Addendum, I was looking at: Lippmann, John; Mitchell, Simon (2005). Deeper into Diving (2 ed.). J.L. Publications. p. 123. {{cite book}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link) to see if Dr Mitchell expressed his opinion there, but only found "Initially, the body becomes rigid and the victim loses consciousness. Breathing stops and the airway can become obstructed. If decompression (e.g. ascent) occurs at this stage a lung injury could occur." The observations concerning lack of expiratory obstruction seem to be post-2005 or so and may not yet have found their way into print. I'll keep looking. --RexxS (talk) 19:46, 26 May 2009 (UTC)

Gave up looking and expanded the section anyway. Dr Mitchell is an acknowledged expert, so his opinion is usable as a WP:RS as long as that's clear. Hope it now meets all concerns. --RexxS (talk) 21:04, 26 May 2009 (UTC)

I think the key here is knowing what Simon had in mind. Leaming et al. wrote a paper in 1999 looking at airway patency with seizures. It showed that laryngeal muscle activity was not coordinated and became a airway limitation during inspiration. This showed that the loss of an airway was not a problem for an ascending diver (or on expiration). The question left in my mind is related to water introduced into the airway from a lost regulator. Could this cause a laryngospasm? I don't know if the answer to this is clear. The choice is then to start an ascent and risk potential AGE (which will always be a risk, seizure or not) or stay at depth and risk an almost certain drowning.

• Leaming JM, Terndrup TE, Ognibene S (1999). "Glottal patency during experimental cortical seizures in piglets". Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine. 6 (7): 682–7. PMID 10433526. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

I like the current revision of the article by RexxS but think we are close to WP:NOTHOWTO. --Gene Hobbs (talk) 21:22, 26 May 2009 (UTC)

Laryngospasm has been a concern of mine since I started revising our Diver Rescue course around 1994. You avoid cold water triggering it by steady ascent, thus expelling air and preventing water ingress. I agree the passages following look close to HOWTO, but I still think we are on the right side of encyclopedic if we are summarising the procedures in a section called "Management". I'll have a think and see if I can reformulate the "step-by-step" narrative. It is a problem gluing together lots of other editors' contributions and finding a consistent style. BTW - what do you think of a quote box? Might use it instead of my scleral buckle cartoon if my daughter doesn't get round to drawing me a proper image. --RexxS (talk) 21:49, 26 May 2009 (UTC)

Quick FAC review

I am no expert and have not had the time to read the article in detail, but here are some thoughts I had from a quick pass-through. Overall the quality is excellent. Nice work! As is usual in reviews, though, I'll focus on problems that I found:

1. I don't see any summary of Epidemiology or of Society and culture in the lead. Every top-level section should be summarized, if only very briefly, in the lead; please check this.
2. Hyperoxia (elevated levels of oxygen) is not the same as oxygen toxicity, and the lead and body should be reworded to avoid this confusion.
3. The Mechanism section left me mystified. Quite a bit of context is missing. For example, are we talking about oxygen levels in the blood, the brain, or elsewhere? Another example: the section does not clearly state the relationship between oxidative stress and oxygen toxicity. Reading between the lines I get the impression that it's not known how oxygen toxicity really works; if so, the article should explicitly state what isn't known (assuming we can find reliable sources on this, of course). Anyway, please look at that section, pretend that you know nothing about the mechanism, and then explain it using terms that the general reader will understand.
4. All images should have alt text for readers who can't see the images; see WP:ALT and WP:ACCESSIBILITY.

   All images have alt text now, but some of the alt text is not that useful. The alt text should describe what the image looks like, not what it is. The idea is to help readers who can't see the image. So, the following alt text entries are not that useful and need to be reworded:

   • "Three men inside a pressurised chamber" We cannot see that the chamber is pressurized. Just (briefly) describe what can be seen. Can we see what the men are doing, for example?
   • "Microscope slide of a stained slice of rat lung" We cannot see that it's done by a microscope, or is a rat lung. (Come to think of it, I'm not sure what this image is for, as a naive reader probably can't make heads or tails of it even if they can see it; perhaps the image should be removed?)
   • "Photograph of Paul Bert, French physiologist." Most naive readers won't know Bert from a hole in the ground so this text won't help. Pretend you need to describe the photo very briefly over the telephone, to someone who doesn't know Bert.
   • "A diving cylinder containing nitrox." Again, the reader can't see the nitrox. Most readers won't even be able to see a diving cylinder. Just say that it's a shiny white cylindrical container with a half-sphere cap and labels that say X and Y and Z, since that's all that can be seen.

5. The long extended quote from Gilbert 1997 should be replaced by text of our own, preferably supported by a more-recent source (see below):
6. Please omit month names in scholarly citations; there's no need to bloat the article with "(December 1964)" when "(1964)" is just as useful and easier to read.
7. Please use a consistent style in journal titles; some are capitalized and others are not. I suggest standardizing on capitalizing the first letter of every important word, as this seems to be the usual style in this article.
8. There's a bit too much boldface in the references section. The worst example is "Ninth international symposium of the Undersea and Hyperbaric Medical Society" but there are several other examples. Also, parts of titles should not be wikilinked, just as quotations should not be wikilinked.
9. Some topics and/or sources that seem relevant but are not discussed:

• Sola 2008 (PMID 18458550) and Tin & Gupta 2007 (PMID 17337663) on oxygen toxicity and newborns.
• Role of cytokines and O toxicity. See Bhandari & Elias 2006 (PMID 16781448).
• Mechanism within mitochondria. See Min & Juan-xing 2007 (PMID 17276741).
• Relationship between chemotherapy and oxygen toxicity. See Grocott 2008 (PMID 18456212).
• Hyperoxia as treatment for brain injury, and its risk of oxygen toxicity. See Diringer 2008 (PMID 18388679) and Rockswold et al. 2007 (PMID 17439701); these sources disagree. A brief motivating discussion for why someone would use treatments for which there is a significant risk of oxygen toxicity.
• The functional tradeoff in diving between nitrogen narcosis and oxygen toxicity. See Schwerzmann & Seiler 2001 (PMID 11524902).
• The role of colostrum as a defense against oxygen toxicity in newborns. See Debier 2007 (PMID 17628181).
• This is just from a quick search; perhaps some of these bullets are not needed, but quite possibly I also missed some bullets.

Eubulides (talk) 19:47, 24 June 2009 (UTC)

Thanks very much for those comments. My apologies, I hope you'll excuse my rudeness in refactoring them, but it is a big help to me to have them numbered, so I can see what I've tried to address.

1. I've added a paragraph to the lead, summarising "Society and Culture". I had hoped that the last sentence in the third paragraph summarised Epidemiology, but I can expand it if you think it necessary.

2. As I understand it, hyperoxia is simply an excess of oxygen in the tissues, while oxygen toxicity is the possible effect resulting from hyperoxic conditions. Unfortunately, Hyperoxia redirects to this article, so I attempted to follow the suggestion in MOS that such redirects should be bolded on first occurrence, so that readers know they have arrived at the correct article. The use of hyperoxia as a possible article title was discussed in the section "Hyperoxia" above. I've now re-written that part of the lead. I hope it meets your concerns. I have searched through the body text for hyperoxia, but I cannot find places where I've misused it. The sources seem to follow the same pattern: hypoxia to refer to a condition where an excess of oxygen exists in tissues; oxygen toxicity when damage has occurred. But I'd be happy to correct any errors I've missed.

3. The mechanism section has the problem that several different editors added parts of the text over time. I attempted to draw them together and cite them, but I've now expanded it somewhat to try to make it more accessible to the casual reader. Please let me know how you feel about the section now.

4. Alt texts are being done now.

I'll be able to address 6,7,8 tomorrow, if not sooner. 5 has been a problem. I wanted to illustrate the relative prevalence of ROP between developed and non-developed areas, and the caption should explain that, but its original caption was WP:SYNTH. Clare Gilbert's quote did the job very well for me, so I'll try to summarise what she said and cite her instead.

9. Finally, thank you also for the sources you provided. As I am a diver, not a medic, I am much less familiar with recent medical literature. I'll try to get sight of as many of those as possible to see what I can add (although I'm conscious that the article is quite long already), but that may take some time. --RexxS (talk) 00:58, 25 June 2009 (UTC)

Thanks for the prompt work so far. You're right about hyperoxia, of course. This article need not worry about names of redirects, but to save any grief on that score I resurrected Hyperoxia as a separate article. I struck the items you've done so far (and expanded one). Oh, and I fixed the article's first image to be smaller (i.e., fewer kilobytes), to address a problem noted by Materialscientist. Eubulides (talk) 07:16, 25 June 2009 (UTC)

6. I think I've corrected all the excess month parameters. I've left the few where the date of publication is not clear because there is no pmid or issue (mainly web cites).

7. I've capitalised journal titles as you asked. It does look better now.

8. The bolding is mainly due to my collaborator, Gene Hobbs, who supplies most of the references, trying to fit reports and papers into the format for {{cite journal}}. I've read through {{cite paper}} (same thing, it seems) and made use of the examples there to recast |volume as |journal and been a bit constructive with |publisher to make sure information is not lost. That should fix the problems with bolding.

9. Having checked, I already used the Tin & Gupta study (Oxygen toxicity#cite note-Tin-61 at present), but I'll search out the Sola ref to see if there's more to add.

9. The Schwerzmann & Seiler study is really relevant mostly to Decompression sickness and Nitrogen narcosis (coincidentally, the very two articles I'm working on now, to get them to GA). Nowadays, there is no trade-off between nitrogen narcosis and oxygen toxicity: the addition of helium to make trimix (breathing gas) is a simple solution universally adopted for deeper diving.

9. I'm interested in the Diringer and Rockswold studies, but in my humble opinion they properly belong in the Hyperbaric Oxygen Therapy article, (which is linked from the lead here). We already have several references to HBOT in the cites, and I'm not sure if I can justify adding more. But I'll gladly take your advice on this.

9. I'll carry on searching the other refs you gave, to see if I can find useful material.

4 and 5. Still thinking about how to do those! --RexxS (talk) 17:29, 25 June 2009 (UTC)

4. I've redone the alt texts, trying to follow your guidance. The one place where I fear I have to disagree is the diving cylinder. I have a good friend who is registered blind (he actually has 1/6 vision) and I taught him to scuba dive. He would recognise what is meant by "diving cylinder", but the "shiny white cylindrical container with a half-sphere cap" wouldn't make much sense to him here. I think that sometimes the context has to be stated, or at least an assumption made on what nouns are recognisable to a visually-impaired person. In other words, where do we stop? If we have to describe a "diving cylinder", do we have to describe a "cylinder"? I took the time to read through WT:Featured article candidates#Alt text in images, and I hope I am seeing your point - I really do agree in general, but that image is aimed squarely at readers who have some knowledge of scuba diving, so I feel I can assume some context. Anyway, let me know what you think, perhaps there's a formulation we can both agree on. --RexxS (talk) 18:07, 25 June 2009 (UTC)

5. The more I think about the caption for the ROP graph, the more I'm convinced that Clare Gilbert's quote gives exactly the message that I wanted to portray. Is there a policy or guidance against the use of quotes in captions? I'm just trying to understand why you prefer us to use our own text. --RexxS (talk) 19:59, 25 June 2009 (UTC)

5. I was asked to redo the ROP chart, so took the opportunity to see if I could rephrase the caption into my own words, without losing the original thrust. Does it meet with your approval? --RexxS (talk) 23:04, 28 June 2009 (UTC)

• Thanks. The ROP chart looks nice. All of my above points have been addressed, except for (9). You may be right about the Diringer and the Rockswold studies. I guess my problem is that I don't see a clear presentation in the article of what oxygen toxicity is a tradeoff for, in therapy. That is, the article says that HBOT can cause O toxicity in certain cases, but it doesn't briefly say why those cases are so common, or why there is a tradeoff between risk of O toxicity and something else (whatever that happens to be). I've tried to edit (9) above to say that.
• "Nowadays, there is no trade-off between nitrogen narcosis and oxygen toxicity: the addition of helium to make trimix (breathing gas) is a simple solution universally adopted for deeper diving." Thanks, I did not know that (I'm no diver). Surely this point is important enough to put into the article? I don't see it there.

Eubulides (talk) 23:29, 29 June 2009 (UTC)

Thanks for that. I'm very wrapped up in diving, so need reminding that what's obvious to me often needs to be explained. We have some content in articles like Nitrogen narcosis, Trimix (breathing gas), Technical diving, etc. However, I've added a paragraph to "Prevention" "Underwater" with a summary and liberally wikilinked to those other articles. Please let me know if you want it expanded.

I'm not quite sure what you are looking for regarding trade-offs. Would it be helpful if I state what I know here and you can tell me what if anything I need to add?

First, there aren't any trade-offs with CNS oxygen toxicity. If it happens underwater, then it wasn't a trade-off: somebody or something screwed up or pushed the limits too far. If it happens during HBOT, it happens. The attendant removes the patient's mask and waits for the patient to recover: No long term harm: No big deal. It's much the same for ARDS - see the last comment in #Mechanism on this page, where the anon says "[Pulmonary] oxygen toxicity has been called "the sasquatch of the adult ICU: often feared but never actually seen".

BPD is a different matter though, even more so ROP. The tension here is between the beneficial and the antagonistic effects of the oxygen on a developing infant. This is addressed by restricting the fraction of oxygen and duration of exposure to empirically-derived limits; as well as by screening for ROP. have a look at "Causes" " Pulmonary toxicity" and " Prevention" " Normobaric setting" to see if you want them expanded. You might look at Axl's comments in WP:Featured_article_candidates/Oxygen_toxicity/archive1 (where we are debating ad nauseum what's worth including in Epidemiology about ROP) to get some idea of how the fear of ROP has changed practice in oxygen delivery to neonates over the past 60 years. Silverman's article is an interesting source.

I admit I haven't found the time to search out the other refs you suggested yet. I wasn't quite prepared for the time I needed to address all the comments so far. --RexxS (talk) 01:52, 30 June 2009 (UTC)

• Yes, FAC is always more work than one thinks it'll be, even if you've done it before. Thanks for all your efforts, though; they really are improving the article.
• Your previous comment is much clearer than what's currently in the article now. I just now reread the article, and this stuff is scattered all over the place, and the organization makes it hard for a non-expert like me to follow. For example, Causes has three subsections Central nervous system toxicity, Pulmonary toxicity, and Ocular toxicity; but none of these subsections are really about the causes of oxygen toxicity; they are about different forms of oxygen toxicity. Now that I understand things a bit better, I see that properly speaking, almost all this material belongs under Classification (of the different types of oxygen toxicity); Causes should say something like "Oxygen toxicity is caused by exposure to excess oxygen" (duh, right?) and then it should go on to say why one would be exposed to excess oxygen, and then list diving, HBOT, etc. as the main causes and why people tolerate the existence of these causes. Such a section could provide the motivation that I see as lacking in the article (but which is wonderfully present in your previous comment).

Eubulides (talk) 06:20, 30 June 2009 (UTC)

Thank you. I will try to see how I can address this. However I perceive that my efforts are going to have to be a compromise. Part of the problem is that this article is actually three-and-a-half articles in one. As you spotted, there are (1) the effects of oxtox on divers; (2) BPD; (3) ROP (plus some extra bits like EVA). These areas are related only by being caused by toxic effects of oxygen. The original article was about oxtox in divers. BPD and ROP were added later and the article was at that time organised effectively by classification. Since this article falls within the scope of Medicine, it had to conform with WP:MOSMED#Sections to ensure comprehensiveness. Througout, there has been a tension between medics wanting conformance to MOSMED and non-medics who prefer to give more weight to other considerations (for example: about the order of sections). So I either needed to make three top-level sections with ten subsections each, or go for ten top-level sections, each of which described three areas. Because the former layout would produce a massive amount of duplication, I chose the latter. As you can see, most of the sections deal with diving, BPD, ROP, in that order. That is part of the reason why facts relevant to a particular theme are scattered. I should mention that "Causes" should include risk factors (see Talk:Oxygen_toxicity/GA2), so much of what is there concerns the circumstances in which oxtox may arise. The audience for this article is also diverse: divers, medics and general public. It is probably a task beyond my capabilities to fully satisfy all three; and it may be that this topic is inherently too broad to properly meet FA standards.

Nevertheless, my experience of using MOSMED to structure articles has been very positive, so I feel constrained to stay with it. I think that an extensive rewrite of "Causes", as you suggest, should be the likeliest course. --RexxS (talk) 17:00, 30 June 2009 (UTC)

Further: I've made a first attempt by writing an introductory paragraph for "Causes" and for "Prevention", trying to give an overview of those and incorporating some of what you wanted to see about trade-off (I think). I know it's not ideal, but is it a step in the right direction? --RexxS (talk) 18:21, 30 June 2009 (UTC)

Citation format issues

I just now installed a change to regularize citations a bit, as follows:

• Omit URLs to non-free articles. The PMID and DOI suffice for these. This is the usual style in Wikipedia medical articles.
• If a URL is rewritten to something that looks stable, use the target of the rewrite, instead of the source. This tends to work better in practice (for example, it tends to end in ".pdf" for PDF files) and it is less work on the client browser and network.
• Omit accessdate= for archival journals.
• Omit accessdate= for citations that don't have a URL.
• Omit format=PDF unless the immediate destination is PDF.
• Don't use Google Books URLs; they're not reliable (e.g., when someone's "quota" is exceeded) and they give out info about the original reader.

One other thing. I propose that the article consistently use ISO format dates (e.g., "2009-06-29") for access dates. The article is currently inconsistent about this. This is a common style in Wikipedia, even in articles where other dates are formatted in non-ISO style. Eubulides (talk) 08:05, 29 June 2009 (UTC)

You might have seen the discussion on Google book links at FAC talk page. I don't know your position and final FA position, but I felt it is not a clear cut issue, and many do support keeping those links. Materialscientist (talk) 09:10, 29 June 2009 (UTC)

The main thing that bugs me about Google Books is that they often don't work for me, or for other readers who share IP addresses through a pool. I constantly get "quota limit exceeded" when reading Google Books. I also object to them on privacy grounds, but I suppose if an editor wants to expose personal info via Wikipedia to Google (and presumably to others) then that's the editor's business. Eubulides (talk) 09:24, 29 June 2009 (UTC)

Could you explain in few words privacy problems ? Materialscientist (talk) 09:30, 29 June 2009 (UTC)

As I understand it, each visitor to Google Books gets different URLs (for the same book). This lets Google track who originally read the book and added it to Wikipedia. Eubulides (talk) 16:52, 29 June 2009 (UTC)

The only private information that they could encode or store is your IP address (and what browser you're using). Anyway, I always find Google Books URL's too long, so I hack them down to the bare minimum needed to show the page before I use them. --RexxS (talk) 18:14, 29 June 2009 (UTC)

Surely they could encode more private information than that! Cookies, for starters. All the "bare minimum" needs to do is to encode a private ID of some sort, and Google can decode it to get all the other info. Eubulides (talk) 21:24, 29 June 2009 (UTC)

(slightly off-topic:) Cookies will only contain data that a webserver tries to put onto the local machine, so they can't contain anything about you the webserver doesn't already know. All the webserver knows about you is what it can read from the "HTTP Request Header", which your browser sends (unless you fill in forms to give it more info). There's a full list of these headers here. To be accurate, the webserver can read your IP, browser type, preferred language, and acceptable charactersets and encoding. But that's all the "personal" info it can get. So, yes, in theory Google could encode that info into the url you are served. Then they might be able to say that a PC that had IP:WW.XX.YY.ZZ on such-and-such a date, using Firefox and preferring US English was the one that put their url into Wikipedia. If they then went through the edit history, they could find your usename. So the concern is really that Google could checkuser you! --RexxS (talk) 22:58, 29 June 2009 (UTC)

(o/d) Thank you for your help in regularising the citations. However, with all due humility, I disagree with some of the advice you have kindly given.

1. I took my linking advice from the documentation from Template:Cite journal, which was the commonest template used. It says of the |url= parameter:
   • url: This should point to, in descending order of preference:

   1. A free online version of the full text
   2. An online version of the full text, for which subscription is required
   3. An abstract or information page, if no DOI or PMID record is available

   If a DOI or PMID is available, the URL should only be specified if it would point to a different page to that which a DOI or PMID would redirect to.

   I read this to say that if a free online version of the full text is available, it should be linked, as long as it's not the page that the PMID points to. Similarly we should link to subscription versions of the full text, if free is unavailable. The reader can always click on the PMID link to get a stable summary, so why not give the link to the full text?

2. The other side of this is that online documents are sometimes updated, with a slightly different filename (date for a CV, for example). The site maintainer will change the link from the download page - a job I have to do regularly as I run three large webservers for numerous clients. So there is an argument that the URI for the download page is more likely to be stable than that for the actual document. I agree this may be of less concern for pdf's of scholarly works.
3. I think that the |accessdate= parameter should always be present when the linked page (per above) is different from the PMID summary page, for obvious reasons.
4. I agree that |accessdate= shouldn't used without |url= (I thought I'd made sure there were none in this article).
5. Sometimes the url doesn't contain a .pdf extension, but actually initiates the download of a pdf. For example, this diff where I was checking links and found that to be the case. You've delinked that now, but the PMID only shows a summary and the full text was available as a pdf for free. I really think that should be reverted.
6. Google books seems to be under discussion. There is the possibility that the reader may be able to benefit from such links and little likelihood of harm. Unless FAC criteria decide against them, I'd rather give the reader the choice, but I'm content to be guided by you here.
7. After reading another FAC article being criticised for using ISO for access dates, I looked up what our guidelines are. MOSNUM is clear that all dates within an article should be in a consistent format: there's no exemption for accessdates. I understand that the examples in the citation templates use ISO (and that's been criticised as well), but that doesn't seem like much of a reason for inconsistency to me. Anyway, I spent a couple of hours late last night trying to put all of the accessdates into DMY.
8. I think you may be confusing WP:EL with WP:RS. Although login sites are specifically disallowed for external links, they are perfectly allowable for citations (e.g. American Journal of Physiology). I would suggest the citation containing the link to ftp://ftp.decompression.org should be there to support the text.
9. I cannot believe that an online reproduction of Bert's text (he died in 1886) could possibly attract copyright. Is it simply that the host is "Internet Archive" or have I missed something?
10. I was aware of the problems surrounding YouTube, so spent quite some time and effort tracking the provenance of that YouTube video - see #YouTube video on this page. Unless you can still see a good reason not to include it, I really think it should be restored.

Thanks again for all your help. It is appreciated --RexxS (talk) 18:03, 29 June 2009 (UTC)

I have been away at the UHMS Annual Meeting but I second the statements and interpretations of RexxS above.

Generic log in information is available for ftp://decompression.org with user name: downloadfiles and password: decompression1 From public post by site author here (but this does require log-in) and re-posted by me a while back here. I am not sure how this should be handled though I feel this information should be included.

Thanks for all these comments and thanks to RexxS for taking all the time to follow-up! --Gene Hobbs (talk) 18:29, 29 June 2009 (UTC)

MOSNUM, EL, registration, copyright, etc.

• "I looked up what our guidelines are. MOSNUM is clear that all dates within an article should be in a consistent format" That's incorrect. WP:MOSNUM #Format consistency says that the dates in article references should be consistent with each other, but it does not require that they use the same format as dates in article body text. It's fairly common for citations to use YYYY-MM-DD and for main text to use "DD Month YYYY". Part of this is because multiple (non-Wikipedia) citation standards recommend YYYY-MM-DD.
• "I spent a couple of hours late last night trying to put all of the accessdates into DMY." You got a sizeable fraction of them, but missed nearly as many (I didn't count 'em). It would have been better to leave them alone, as they were all (or almost all) in ISO format. I hope it's OK if I change them back to the way they were.
• "I think you may be confusing WP:EL with WP:RS."

• Yes, I was, sorry; I got confused because that source was listed both as an external link (where it was clearly inappropriate) and as a citation.
• In this particular case, with the information supplied above I was able to construct a URL that works without requiring registration, and resurrected the citation with this new URL; this should make the issue moot.
• I disagree that links to sites requiring registration are "perfectly allowable"; they are controversial. But that topic is now moot here, I hope. (Thanks, Gene Hobbs!)
• Usually if there's a citation to a source, there's no need to list the source as an external link too, so I didn't restore the external link. Usually it's better to keep external-link sections small, but if you'd rather have this in the external-link section, please feel free to move the URL there.

• "I cannot believe that an online reproduction of Bert's text (he died in 1886) could possibly attract copyright." On the contrary, it's most probably copyrighted, as it is a translation published in the U.S. in 1943. Assuming the publisher is at all competent and renewed the copyright, the translation is still under copyright even though the original French work is not. Quite plausibly that is why the original web site was taken down. It would be fine to link to a faithful copy of the original French instead; would that be a reasonable substitute?
• "I was aware of the problems surrounding YouTube, so spent quite some time and effort tracking the provenance of that YouTube video - see #YouTube video on this page." Thanks, I wasn't aware of that, and it sounds like we can get permission to use it. However, my understanding is that we must have have written permission from the copyright owner that satisfies a particular legal format, when we are wikilinking to material that has been published on Youtube without the copyright holder's permission to republish to the world. This is because of the doctrine of contributory infringement. If I'm right, that email doesn't doesn't suffice to protect Wikipedia legally. Could you please follow this up as described at Wikipedia:Requesting copyright permission? Until this is resolved by the book, I'd remain leery of linking to that resource.
• "I read this to say that if a free online version of the full text is available, it should be linked" Yes, that's right. And if the URL points to a non-free text, then it shouldn't be used. Those are the URLs I removed.
• "Similarly we should link to subscription versions of the full text, if free is unavailable." Only if no DOI or PMID record is available that would point to the same resource. I believe that all the scholarly-journal URLs that I removed were ones that also had DOI or PMIDs.
• "I agree this may be of less concern for pdf's of scholarly works." Yes, those are supposed to be stable. The typical Wikipedia style is to omit accessdate= for these resources.
• "I think that the |accessdate= parameter should always be present when the linked page (per above) is different from the PMID summary page," Not for URLs maintained by publishers of scholarly works. These are archival journals, and they're supposed to be stable URLs. The "Retrieved on" clause is just useless clutter for these citations. All the featured articles that I know of routinely omit accessdate= for these sources (please see Autism for example).
• "Sometimes the url doesn't contain a .pdf extension, but actually initiates the download of a pdf." Yes, in that case, "format=PDF" is appropriate. However, as far as I know, no such cases remain in the article. In such cases it's better to link directly to the target of the redirect, assuming the target is stable, and in that case the "format=PDF" is also appropriate for the target.
• "Google books seems to be under discussion. There is the possibility that the reader may be able to benefit from such links and little likelihood of harm." There's certainly harm for me. I see a URL, I click on it, and it typically doesn't work. So I've wasted my time as a reader. This issue was not mentioned in the earlier discussion, but it's a real issue.

Eubulides (talk) 21:24, 29 June 2009 (UTC)

• Ah, but that's cheating - you moved the goalposts by removing all the month/day parameters! When I started changing the ISO dates, this was the first reference: Donald, Kenneth W. (17 May 1947). "Oxygen poisoning in man—part I". British medical journal (4506): 668. doi:10.1136/bmj.1.4506.667. PMC 2053251. - notice that it's the template that outputs DMY by default and I don't know how to change that. So I figured I'd have to change all the others  :(
• Well it was late last night. I have no objection if you want to change the accessdates back to ISO and I'll gladly check them over afterwards.
• Gene is my regular collaborator and the one who finds all the refs that I can't. But your format user:[email protected] was a stroke of genius. Kudos.
• Mea culpa, I'd forgotten the fact that it was a translation. I'm all in favour of providing free text to our readers where we can (even in French), so let's see if we can find one.
• I wasn't aware of our particular requirements for a legal format for linking to YouTube (I know that where we embed a video, we have to get GFDL), so I'll leave that out until I find time to pursue it properly.
• OK - I read the documentation for {{cite journal}} to mean that we should additionally link to a pay-for full text version (if a free one wasn't available) rather than just to a PMID summary.

It looks the current version of the article may now satisfy all of the comments, thanks to you, Axl and Materialscientist. I hope some of the regular reviewers will support or it looks like it might get archived. --RexxS (talk) 22:25, 29 June 2009 (UTC)

Dr Ox

Thanks to Materialscientist who has provided a good summary of the story. I thought I'd put together a suggestion for a paragraph for "Society and culture" here and get some input before insertion into the article:

---

Victorian society had a fascination for the rapidly-expanding field of science. In Dr. Ox's Experiment, a short story written by Jules Verne in 1874, the eponymous doctor uses electrolysis of water to separate oxygen and hydrogen. He then pumps the pure oxygen throughout the town of Quiquendone, causing the normally tranquil inhabitants and their animals to become aggressive and plants to grow rapidly. An explosion of the hydrogen and oxygen in Dr Ox's factory brings his experiment to an end. Verne summarised his fable by explaining that the effects of oxygen described in the tale were his own invention.

---

All contributions welcome! --RexxS (talk) 20:26, 29 June 2009 (UTC)

I have also updated Dr. Ox's Experiment for consistency. Corrections here are that Quiquendone was a town, not vollage; and I will tell more about the story and you decide how to treat it: the action of oxygen was that plants were growing up rapidly, animals and humans became not lively but overly aggressive. Thus although "lively" does sound more logical, Verne apparently had his own ideas. Regards. Materialscientist (talk) 22:48, 29 June 2009 (UTC)

I'll put the revised version (above) back into the article now. Please edit it mercilessly if you can improve it. --RexxS (talk) 14:11, 2 July 2009 (UTC)

Unverified Bornstein source

The following text in the article

• "The first recorded human exposure was undertaken in 1910 by Bornstein when two men breathed oxygen at 2.8 bar (280 kPa) for 30 minutes while he went on to 48 minutes with no symptoms. In 1912, Bornstein developed cramps in his hands and legs while breathing oxygen at 2.8 bar (280 kPa) for 51 minutes."

was supported by the following citations:

• Bornstein, A. (1910). "Versuche über die Prophylaxe der Pressluftkrankheit". Pflügers Archiv European Journal of Physiology. 4: 1272–1300.
• Bornstein, A.; Stroink, M. (1912). "Ueber Sauerstoff vergiftung". Deutsche medizinische Wochenschrift. 38: 1495–7.{{cite journal}}: CS1 maint: multiple names: authors list (link)

I just now checked the first citation, and it can't possibly be right. Volume 4 of that journal was in 1871, not 1910. While checking into this I discovered that what appears to be the real source for all this text is Acott 1999, page 151, column 2, paragraph 4. My guess is that no Wikipedia editor has actually read the above two sources. If my guess is correct, then the article should not cite them. Regardless, I fixed this particular problem by removing the two citations and citing Acott 1999 instead.

Are there any other instances of this sort of thing in the Oxygen toxicity article? If so, they should be fixed too. A Wikipedia article should only cite sources that a Wikipedia editor has actually verified. More generally, while it is impressive in a scholarly journal to cite obscure sources in other languages, it's not that useful in Wikipedia. Typically it's better here to cite recent and easily-accessible reviews in English, and to omit citations to ancient sources that most readers can't get and couldn't read even if they could get them. That is particularly true where the real source is the more-recent English citation. Eubulides (talk) 23:04, 29 June 2009 (UTC)

I don't have access to those journals so I don't think I supplied those cites (although I can read German), but I agree it does look like they came from Acott's article at Rubicon. In which case the first cite is certainly given as:

• Bornstein A. Versuche uber die Prophylaxe der Pressluftkrankheit. Pflug Arch 1910; 4: 1272-1300

(page 155, ref 13) - which would mean Acott's cite is wrong. Bennett & Elliott doesn't cite Bornstein so that's no help.

The second cite also looks like it came from Acott's list of references (ref 14), but John Clark also cites it in Pulmonary oxygen tolerance in man and derivation of pulmonary oxygen tolerance curves as

• Bornstein, A. and Stroink. Regarding oxygen poisoning. Deutsche Medizin. Wochenschr. 32:I495-I497, 1912.

(page 339, ref 57) - as best as I can read it. So there's a difference between volumes there as well (maybe even pages).

If we want to find out the correct cites, then I can ask Gene Hobbs - he's the best ref detective I know.

Anyway, I take your point completely about preferring to cite Acott, rather than the original papers for all the reasons you give. I can now see a problem that I hadn't thought of before: I've only been editing this article since June 2008, and it's been around since February 2004, and I'm by no means the sole contributor. How can I attest that all the cites are valid? I can check the ones I have access to, and I can vouch for the ones that I added; but what should I do about the others? --RexxS (talk) 00:21, 30 June 2009 (UTC)

If you can list the citations that you lack access to, Gene Hobbs and I can try to verify them. If none of us can verify them, we can list them here for others to verify, and/or ask the editors who originally added the sources (many of whom are probably no longer active), and/or simply delete them. Surely there aren't that many unverifiable sources in this article. I do have access to a medical library so I should be able to handle the medical side fairly well. Eubulides (talk) 06:27, 30 June 2009 (UTC)

I've now verified all of the citations that have their title linked or have a PMC ID. I think I've also checked the summaries for every PMID (although I'm going a little bleary-eyed with those). I can vouch for all of the cites using {{harvnb}} as I know I double-checked them when I converted them to harvnb - also 73 (as I just added it), 104 (as I only checked it yesterday) and 108 (as that's Donald's book and I know I added that). That leaves 11, 31, 79, 81, 92, 101, 105, 106, 107, 110, 111.

In addition, I'd like to ask if you think the formatting in 40 and 88 is as good as it could be? Thanks, --RexxS (talk) 21:49, 30 June 2009 (UTC)

Bornstein's Versuche über die Prophylaxe der Pressluftkrankheit is the wrong journal, it was in Berliner klinische Wochenschrift and I have a copy on the way; 11 is on Highwire; 31 is a valid ISBN in WorldCat; 79 is correct - have it here; 81 is right; 92 is correct - have it here; 101 I am not sure about; 105 is a valid ISBN; 106 and 107 are correct (again Highwire); 110 and 111 are correct - have them here. Sorry, not sure this helped much. --Gene Hobbs (talk) 23:22, 30 June 2009 (UTC)

It certainly has helped hugely. Thank you. (I hope Eubulides can see what I mean now!) That leaves 101. And I can solve that one. The article by Weslau is cited here as:

• Weslau W, Almeling M. Incidence of oxygen intoxication of the central nervous system in hyperbaric oxygen therapy. In: Marroni A, Oriani G, Wattel F, editors. Proceedings of the international joint meeting of hyperbaric and underwater medicine, Milan. Victoria: Graphica; 1996.

which may give us a bit more information. But that doesn't matter, because the text it supports: A study by Welslau in 1996 reported 16 incidents out of a population of 107,264 patients (0.015%) is actually discussed in this:

• Yildiz, S.; Ay, H.; Qyrdedi, T. (2004). "Central nervous system oxygen toxicity during routine hyperbaric oxygen therapy". Undersea and Hyperbaric Medicine. 31 (2). Undersea and Hyperbaric Medical Society, Inc: 189–90. PMID 15485078. Retrieved 3 October 2008.{{cite journal}}: CS1 maint: multiple names: authors list (link)

which we have already. I'll drop the Weslau and just use Yildiz as a reliable secondary source which is immediately available. (Sorry that decreases all the numbers after 100 by 1) --RexxS (talk) 00:52, 1 July 2009 (UTC)

A few more recent sources on oxygen toxicity

I did some more searching and found the following recently-published reviews that seem like they may be directly relevant to oxygen toxicity (not that I'm an expert).

1. Bitterman H (2009). "Bench-to-bedside review: oxygen as a drug". Crit Care. 13 (1): 205. doi:10.1186/cc7151. PMID 19291278.{{cite journal}}: CS1 maint: unflagged free DOI (link)
2. Auten RL, Davis JM (2009). "Oxygen toxicity and reactive oxygen species: the devil is in the details". Pediatr Res. doi:10.1203/PDR.0b013e3181a9eafb. PMID 19390491.
3. Allen BW, Demchenko IT, Piantadosi CA (2009). "Two faces of nitric oxide: implications for cellular mechanisms of oxygen toxicity". J Appl Physiol. 106 (2): 662–7. doi:10.1152/japplphysiol.91109.2008. PMID 18845774.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. Thomas W, Speer CP (2008). "Nonventilatory strategies for prevention and treatment of bronchopulmonary dysplasia—what is the evidence?". Neonatology. 94 (3): 150–9. doi:10.1159/000143719. PMID 18679037.
5. D'Agostino DP, Colomb DG, Dean JB (2009). "Effects of hyperbaric gases on membrane nanostructure and function in neurons". J Appl Physiol. 106 (3): 996–1003. doi:10.1152/japplphysiol.91070.2008. PMID 18818382.{{cite journal}}: CS1 maint: multiple names: authors list (link)
6. Matute-Bello G, Frevert CW, Martin TR (2008). "Animal models of acute lung injury". Am J Physiol Lung Cell Mol Physiol. 295 (3): L379–99. doi:10.1152/ajplung.00010.2008. PMID 18621912.{{cite journal}}: CS1 maint: multiple names: authors list (link) (Also see comment on hyperoxia and acute lung injury, and author's reply, PMID 19047485)
7. Imlay J (2008). "Cellular defenses against superoxide and hydrogen peroxide". Annu Rev Biochem. 77: 755–76. doi:10.1146/annurev.biochem.77.061606.161055. This is the quote that got my attention: "Oxygen toxicity is primarily mediated by partially reduced oxygen species that are more reactive than is molecular oxygen itself. Such species are inevitable by-products of aerobic metabolism, and the evolution of enzymes that scavenge them was an adaptation that allowed ancient microbes to occupy aerobic habitats."

Hope this helps and that it doesn't make you tear your hair out. Eubulides (talk) 07:49, 30 June 2009 (UTC)

Not at all, I wish I had the time to read more. Given that I can only see the summaries at present, here are my initial thoughts:

1. I like this. The "margin of safety between effective and potentially toxic doses of oxygen" is fresh to me if it's described quantitatively. PMC2688103 [Available on 2010/02/24] - maybe we can wait? WP:TIND!
2. Doesn't seem to contain much new, apart from "a discussion of potential therapeutic approaches for the prevention and/or treatment of human diseases using enzymatic and non-enzymatic antioxidants" which might be usable to expand the "Prevention" section.
3. Very interesting. I will need to find this. It's from Duke, so I bet Gene probably knows the article and its authors. I'd better ask him first.
4. "[D]rug-related strategies to prevent ... (BPD)" looks worthy, but I get the impression it's early days for this - I've already been gently admonished by Tim Vickers for using claims about superoxide implication in iron take-up, as it was an isolated study, not yet mainstream.
5. Absolutely, undoubtedly, belongs with Nitrogen narcosis.
6. Only weakly related to oxygen toxicity, it seems. Would surely be good for ARDS and Bronchopulmonary dysplasia - which is little more than a stub at present. It has "PMC2536793 [Available on 2009/09/01]" so freely available soon.
7. I don't think that has anything new to add to the "Mechanism" section, apart from the inferences about evolutionary adaptation, and I think that is a detail-too-far for this article. Again, we have an article on Reactive oxygen species and it may be very appropriate there.

Thanks again - I'll go and pester Gene to look at #3 for us. --RexxS (talk) 20:33, 1 July 2009 (UTC)

COPD

Seriously? Under O2 Toxicity? WOW... --Gene Hobbs (talk) 16:43, 5 July 2009 (UTC)

I would have left it as just a mention. However Patel et al (Patel, Dharmeshkumar N; Goel, Ashish; Agarwal, S.B.; Garg, Praveenkumar; Lakhani, Krishna K. (2003). "Oxygen toxicity" (PDF). Journal, Indian Academy of Clinical Medicine. 4 (3): 234–7. Retrieved 2008-09-28.{{cite journal}}: CS1 maint: multiple names: authors list (link)) include "Carbon dioxide narcosis" as part of their review, although the relationship is indirect. Since we don't have an article on Carbon dioxide narcosis and Hyperoxia is a stub, the only place Wikipedia covers this is CO2 retention - which is incomplete and badly named. Carbon dioxide retention redirects to Hypercapnia which has no mechanism and doesn't mention effects on COPD patients.

Anyway, if it has to be in here, I'll try to observe WP:UNDUE and hope that someday those other articles get sorted out, so we can smart-link to topics that give the detail we have here. --RexxS (talk) 19:03, 5 July 2009 (UTC)

<RANT>

I WHOLEHEARTEDLY DISAGREE! It does NOT need to be here.

Many in the field initially resisted a change to the term "oxygen toxicity" and much preferred the old term "oxygen poisoning". The strongest argument against the change was that people would not know the difference between "oxygen toxicity" and the "toxic effects resulting from oxygen". They thought the use of the phrase "high partial pressures" in defining it would help. Even as recently as 1999, Lambertsen would not use oxygen toxicity without also saying oxygen poisoning in the same article. (JAP) We have now proven their concerns to be correct.

In my mind, Chronic obstructive pulmonary disease (COPD) and Retinopathy of prematurity (ROP) for that matter are far from the classic "oxygen poisoning". I indulged when ROP was included because it was listed in Mosby's Medical Dictionary as such and you were able to convince me that this is a good use of the term. With the relationship of COPD used in this article, we should be scrapping ALL other medical disorder articles and redirecting them to hypoxia. After all, people don't die from a hemmorage, Cardiac arrest or any other medical disorder, they die from the lack of oxygen to the tissues and brain. Maybe it's that I am clinging to history a little too much but if it should be included, why is the literature so poor and the use the term "oxygen toxicity" to describe this non-existent?

What are ICD9 and 10 codes for? Nobody I know ever uses these for either COPD or ROP. Might that be because it is not the best description of the disorders? (Yes, this is retorical)

I do agree the topics should be briefly addressed but calling the respiratory arrest resulting from oxygen breathing "oxygen toxicity" is just bad physiology.

And, why are we worried about other articles and their correctness as it relates to this one? If the others are bad, fix them next. If they are so bad that this article can not reach FA without improving them first, so be it. This article is FAR from ready for FA with all this "other" information creeping into it.

</RANT>

I'll obviously respect what ever you all decide and refrain from further comment. Thanks! --Gene Hobbs (talk) 21:02, 5 July 2009 (UTC)

Oh dear. Well, thanks for sharing your opinion with us, Gene. As I commented in the FAC, I don't have a strong opinion about the inclusion of COPD info in this article. However an editor requested it in good faith, so RexxS and I obliged. Would you mind copying this rant across to the FAC page (or I could do it if you consent)? Thanks. Axl ¤ [Talk] 10:09, 6 July 2009 (UTC)

Thanks Axl, I really did not feel strongly enough about this to post it there which is why I placed it here. If you think it should be there. Go for it. Thanks --Gene Hobbs (talk) 10:25, 6 July 2009 (UTC)

"I really did not feel strongly enough about this to post it there".

— Gene Hobbs

It looks like a pretty strong feeling to me. ;-) Axl ¤ [Talk] 06:43, 7 July 2009 (UTC)

Concerns regarding Pulmonary Toxicity section

The sentence, "The risk of bronchopulmonary dysplasia in infants, or acute respiratory distress syndrome in adults, begins to increase with exposure for over 16 hours to oxygen partial pressures (ppO2) of 0.5 bar (50 kPa) or more" does not appear to be supported by any of the citations presented. None of the 3 citations presented comment on any particular threshold for time or partial pressure. In fact, the last citation, Thiel 2005, appears to be a citation about modelling treatment of ALI in rats. Am I missing something?

As an aside, should the "Main Article" template be used if BPD is only a portion of the discussion? The BPD article does not comment on ventilator associated oxygen toxicity in adults, for example. Yobol (talk) 19:04, 31 August 2009 (UTC)

Apparently that statement had been in the article in one form or another since 2005. I changed the section with new sources to hopefully better reflect reality. Yobol (talk) 22:31, 31 August 2009 (UTC)

You are correct that the statement had been in place long before I started editing, however I do not believe it to be incorrect. Clark, John M.; Lambertsen, Christian J. (1970). "Pulmonary oxygen tolerance in man and derivation of pulmonary oxygen tolerance curves". {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link), derives an estimate for the toxicity dosage asymptote at 0.5 bar ppO2 and clearly illustrates the variability in time-to-onset for different ppO2, as well as its non-linear nature.

The article benefits by the addition of new sources, but in doing so you have removed the following points and made some errors:

• The principal vulnerability of the lungs is because of their large area and limited anti-oxidant defences. Since expired air usually contains about 17% O2, it is clear that normal respiration eliminates as little as 4% of the oxygen at STP. This implies that the rest of the body will be no more than 0.04 bar below the ppO2 in the lungs once gas equilibrium is reached. This is clearly insignificant as a differential cause.
• You have removed the mention of ARDS, which although a lesser concern than BPD, still exists and belongs in the article - Thiel, for example, is discussing the exacerbation of ARDS when treating with oxygen.
• You have removed the explanation of how 50% FO2 under normobaric conditions translates to 0.5 bar ppO2. You must remember that, although it may be obvious to you, it should be explained for the general readership. In addition, it is important to establish this conversion since scuba divers, in particular, are breathing O2 under hyperbaric conditions and need to understand the difference between 50% O2 and a ppO2 of 0.5 bar.
• You have removed the point about onset time decreasing non-linearly with increasing ppO2 - clearly demonstrated in Clark & Lambertsen.
• You have removed the point about atelectasis - an effect that is difficult to reverse - and how it is differs when breathing normobaric 100% O2 from breathing a ppO2 of 1 bar under hyperbaric conditions, cited by Wittner. In other words, there is a difference in risk factor between high levels of supplemental oxygen and high partial pressures of O2 when diving.

I agree that a cited figure of 14 hours is better than the 16 hours originally there. In general, it is unlikely that such a large revision as you made will improve a featured article, especially when you remove sourced content. I think you should either revert your edit, or better, re-integrate the content you removed.

As for {{main}}, I can see that {{see also}} would have been an alternative, had you not removed all reference to ARDS. As it is, the BPD article should be referred to by one of those templates. If the current BPD article is missing information, then please improve that article. It is not a reason for removing the template here. --RexxS (talk) 23:55, 31 August 2009 (UTC)

To address your points:

1) The statement most certainly does seem incorrect. My reading of the bronchopulmonary dysplasia literature does not recognize a clearly defined oxygen level or time limit for risks for BPD. Likewise, the risk for ARDS is after 48 hours, as I cited in the article (Jackson). The thesis paper by Clark and Lambertsen does not address either BPD or ARDS, so I am baffled as to why you would think that it supports that statement.

2) The risk to the lung due to higher oxygen tension as compared to the rest of the body is well documented in Bitterman 2009, and coincidentally, Clark and Lambertsen that you cited. I do not see in any of the citations in the original version (before my changes) addressing either surface area or limited anti-oxidant effects in the lungs. If you could direct me to where you got this information, it would be helpful.

3)I have not removed mention of ARDS from the article. Indeed, I provided proper sourcing for the statement on ARDS that the previous version lacked. Thiel 2005 was a primary article about the effects of treatment of oxygen toxicity in rats that already had ARDS; it cannot be a source for describing oxygen toxicity leading to ARDS.

4)I placed reference of 0.5 bar back in the article.

5)I do not see a figure saying that, and the word "linear" does not seem to appear in the article. What figure/page are you referring to?

6)I have returned the discussion on atelectasis to the article.

7)I disagree that BPD needs to be referred to with any template. The "main article" template was clearly inappropriate for this section, and since BPD is already wiki=linked, I fail to see why it needs a "see also", especially given that oxygen toxicity is only one of many proposed contributors to BPD including mechanical ventilatory injury, infection, inflammation, etc. I agree the BPD article does need improvement, though. Yobol (talk) 02:49, 1 September 2009 (UTC)

A general note to Yobol. Please understand that the article has passed GA and FA reviews where it was scrutinized to fit various views, and to be understood by non-specialists. A general WP rule is to discuss major rewriting at the talk pages first. With all do respect, no matter how professional you might be, some of your recent edits to this article (thanks for RCP though) may (and perhaps should) be reverted outright merely on this basis, without even looking at what are you trying to convey. Regards. Materialscientist (talk) 00:06, 1 September 2009 (UTC)

If you want, you are more than welcome to revert my changes, per WP:BRD. While I understand you do not want to make too many changes to a featured article, it seems that exceptions should be made for instances (such as this) where factually incorrect information is present, citations that do not match the information, uncited information, etc. is present. Otherwise, I suggest changing the message at the top of the page to "Oxygen toxicity is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please discuss any changes on the talk page before making any changes even if there are factual errors in the article" to avoid any further misunderstandings in the future. Yobol (talk) 02:49, 1 September 2009 (UTC)

I'd much rather collaborate to improve the article by eliminating errors and bringing fresh sources. Your contributions are valuable (and valued) and I'm sorry if my lengthy response suggests otherwise. I think it is important when discussing improvements to be frank, but I'm happy to discuss any of the points here to find what is best for the article. Concerning FAs: a featured article has already been reviewed by multiple editors and many hours of editing time have been invested in its production. It is much less likely that wholescale revisions will improve an FA than they would improve an article that has not already received such scrutiny. So I was merely advising that usually it is better to discuss first.

1. The Clark and Lambertsen thesis was a thorough review of the literature relevant to the onset time and dosage of oxygen toxicity as it was in 1970 and has been well-cited since. It clearly demonstrates the methodology used to determine the minimum ppO2 and timescales that should be considered when determining risk for pulmonary toxicity, of which BPD and ARDS are manifestations. It is inaccurate to say they did not address BPD and ARDS simply because they did not mention them by name. Bitterman 2009 is a very new work and has not yet been as extensively reviewed as the earlier works, hence should be used cautiously (although the author is well-respected in the field, so that would mitigate this factor somewhat). Having said that, I fully agree that there are no precise minimum limits for risk, but still feel that the literature supports the assertion that pulmonary toxicity risk increases above ppO2 of 0.5 bar and timescales greater than 16 hours or thereabouts. To give no indication of commonly-accepted guidelines is worse than giving approximate estimates.
2. I think the statement about lung area and paucity of antioxidant defences was due to Gene Hobbs, so I'll ask him if he remembers the source, as I think we all would be interested. As counter-intuitive as it seems to me, Clark & Lambertsen do support your wording, so I'll concede the point.
3. The Thiel cite was used merely to support the point that oxygen toxicity is a risk factor in the treatment of ARDS. The article wouldn't exist if it were not. I must admit that when looking through the diff of your large edit, I missed the moving of ARDS to a later part of the section, so apologies for suggesting that you had removed it.
4. The convention in Wikipedia is to be consistent in the use of units. If you look though the rest of the article you will see "bar (kPa)" is used for pressure. The {{convert}} template is a useful tool for this. It is only a small point, but this article is meant to represent the best work on Wikipedia and inconsistency in the use of units is not up to that standard. Additionally, we have still lost the explanation that 50% FO2 is equivalent to 0.5 ppO2 at STP. It's needed for the reasons I gave above.
5. At sea level, 0.5 bar (50 kPa) is exceeded by gas mixtures having oxygen fractions greater than 50%, while the rate of damage rises non-linearly between the 50% threshold of toxicity and the rate at 100% oxygen.[2]
6. Thanks.
7. Fair enough. The original intention was this subsection would be a summary of the BPD article, but in the process of GA, PR and FA reviews, it sort of "grew" until it was larger than the article it should have been summarising. Perhaps it would be appropriate to restore it once Bronchopulmonary dysplasia is expanded.

I should add that the section is "Causes", which includes pre-disposing factors and risk factors, so the detail of description of symptoms is excessive here and would be much more appropriate in the "Signs and Symptoms" section. Thanks again for taking the time to discuss. --RexxS (talk) 16:32, 1 September 2009 (UTC)

My comment about reverting was to MaterialScientist's response, basically saying that my revisions "should" be reverted without any consideration as to whether it was beneficial. While this article is undoubtedly well-researched and well-written and did pass review, this particular section did have several problems that needed addressing.

1. Not to belabor the point, but Clark and Lambertsen was not used to justify the original statement as noted in the original sentence (it was not in the three citations that were used to justify it), and as you have pointed out, it did not directly address either BPD or ARDS. Since it could not address either, it is inappropriate to use it as a citation as such. The sentence was not speaking in generalities about "pulmonary toxicity", it was speaking specifically to two separate disease entities associated with oxygen toxicity, which are completely separate diseases. As I noted, there is no general consensus as to how much and how long oxygen administration leads to BPD, so we cannot put in a sentence that suggests otherwise, especially if it is not supported by clear documentation. Likewise, another review (Jackson) clearly states ARDS occurs generally 48 hours after oxygen administration. Clearly Clark and Lambertsen (as well as the other 3 citations used originally) cannot be used as citation for that sentence.

2. It is an interesting point, but one I have not come across in the literature. A citation would be helpful.

3. As you state, Thiel 2005 is a primary article about development of oxygen toxicity in the treatment of ARDS. It is not about the development of ARDS due to oxygen toxicity. As such, it cannot be used to support a statement that states oxygen toxicity leads to ARDS, as it originally appeared in the article.

4. I agree standardization is important. I see you have already adjusted them. I do not see why this equivalency statement needs to appear in the "pulmonary toxicity" section. It seems to me if you think that it is that important for diver information, it would belong in a separate section that addresses diving.

5. I was referring to what page/figure in the Clark and Lambertsen article you are referring to. You cite it as supporting that statement, I do not know what article/page in the Clark and Lambertsen article you are alluding to.

7. Agreed, this can be revisited as the BPD article is expanded.

8. I have no objection to moving the description of symptoms (i.e. the timing of onset, etc) to a more appropriate section, as you see fit. Yobol (talk) 17:32, 1 September 2009 (UTC)

1. Ok - I think I see what you mean. Am I right to think you are are drawing a clear distinction between "pulmonary oxygen toxicity" (which Clark & Lambertsen specifically address) and "BPD"/"ARDS" (which they do not specifically address? If so, then I'd counter that BPD and ARDS can result from pulmonary oxygen toxicity in a particular clinical setting. If there is an underlying risk of pulmonary oxygen toxicity after X time at Y ppO2 in those settings, then that presents the risk of BPD/ARDS under those conditions. I have no difficulty in seeing that you may disagree with that.

2. I've asked Gene Hobbs if he can help out, as he's the expert on citations.

3. Agreed. I think Thiel would be useful to cite a mention of the risk factors when treating ARDS, but you are correct to point out it doesn't directly support the original. Thanks for improving that.

4. The article already has gone through many re-organisations in its structure. It was agreed to adhere as closely as possible to MOSMED#Sections, so separate subsections on diving, infants, EVA, etc. were deemed inappropriate. It is true that CNS toxicity is very much the principal concern for divers (and hyperbaric treatment), although the possibility exists of minor concerns for divers relating to pulmonary and retinal effects. Nevertheless, I'm tending to agree that pulmonary toxicity is almost always a concern at normobaric pressure, so I think I'd go along with simplifying the statements as you suggest. I'll have another look.

5. Sorry, I didn't have a specific figure in mind, but for example fig.15, p.151 shows steep incidence of -2% change in VC at around 11-12 hours and the same for -4% change in VC around 16-17 hours for ppO2 = 0.83 bar. Fig.16, p.153 and the nearby tables show similar onsets at different pppO2 and times. Don't you agree that they are showing risk of onset of pulmonary toxicity at ppO2 in the 0.5 bar to 1.0 bar range and times around 16 hours? There's an interesting section (D. Applications of pulmonary toxicity curves) where they suggest how different limits carrying different risk factors are appropriate under different settings. Pages 161-2 explain the choice of 0.5 bar as the asymptote for the curves they derived. Anyway, I'm almost content with the timescales you present ("asymptomatic period between 4 and 22 hours" and "usually begin after approximately 14 hours"), although I've never seen any literature that shows such a low time for onset as 4 hours at 0.95 bar ppO2 - certainly Clark and Lambertsen found none below about 10 hours at 0.98 bar. --RexxS (talk) 19:23, 1 September 2009 (UTC)

Arbitrary section break

<- I've cleaned up the units to make them consistent with the rest of the article. However, while doing so, I found another concern. I don't feel there is any point in mentioning the possible onset of pulmonary toxicity at 2 to 3 bar ppO2 after 3 hours. It simply doesn't exist in the real world, since CNS toxicity is the primary effect at these levels - and onset is in minutes, not hours - see Donald's results in the table under "Signs and Symptoms". The other problem caused by this sentence is that it breaks up the discussion of breathing oxygen under normobaric conditions, so the next sentences are in the wrong context. I'd suggest removing it altogether, but perhaps someone can see a reason to retain it? --RexxS (talk) 17:28, 1 September 2009 (UTC)

Whether or not it occurs in the "real world" I will defer to someone else more knowledgable, though it does appear in a review article from a major pulmonary journal (Chest) by a reviewer well cited in the literature (and, incidentally in this article), suggesting it has at least some clinical relevance. The placement of that sentence comes before the sentence regarding the different experiments on rats showing different pathological effects due to different pressures, so it seems like an appropriate place in relation to that sentence. Perhaps move those two sentences to the end of the section so as to not break up the discussion on normobaric conditions?Yobol (talk) 17:39, 1 September 2009 (UTC)

What I was trying to say is that protocols to avoid CNS toxicity will almost always remove the possibility of pulmonary toxicity under hyperbaric conditions. There is certainly some theoretical clinical relevance, but it's hard to construct a scenario where it could occur. Possibly a very extended hyperbaric therapy for a very deep dive with a pre-existing oxygen load, but even then there would be periods of breathing air to minimise pulmonary risks. I would agree moving those would be the best course. Please go ahead and do it - I certainly don't want to put you off from editing the article, particularly when there's agreement here on the talk page. --RexxS (talk) 19:23, 1 September 2009 (UTC)

Cause and effect

I have a quibble with the very first sentence, "Oxygen toxicity is a condition..." - actually, technically, it is not. O tox is a property of Oxygen, ie it is toxic at certain concentrations. It is a cause of illness, it is not, in itself, a condition. The fact that the term is frequently misused is beside the point. For example;

• "He was suffering from Oxygen toxicity"    is incorrect.
• "He suffered the effects of Oxygen toxicity"    is correct.

cf.

• "He was suffering from poison"
• "He was suffering from the effects of poison"

I hope that you see what I mean?

Oxygen toxicity ≠ oxygen intoxication

 Chzz  ►  22:23, 31 August 2009 (UTC)

Yes, I see what you mean. The term is often misused. Although I can equally quibble with much of what you wrote. OxTox might as well be a property of the body i.e. it reacts to abnormal concentrations of oxygen; and how does "He was suffering from poisoning" sound?

Anyway, that gets us nowhere. MeSH shows "Hyperoxia", "Previous Indexing Oxygen/toxicity (1966-1994)", "Pathological Conditions, Signs and Symptoms [C23]". I don't expect anyone will suggest that OxTox is a "sign" or "symptom" and that leaves "condition". It's not our place to try to impose our ideas of correct terminology, we have to report what the sources say. Many of them use "Oxygen toxicity" to name the condition (perhaps as shorthand for "Effects of Oxygen toxicity"), so I recommend we follow the usage in the sources, even though we may feel it is not quite right. --RexxS (talk) 00:12, 1 September 2009 (UTC)

Chzz, you are technically correct in your description of the use of the word "toxicity". However RexxS is correct to point out that the phrase "oxygen toxicity" is indeed used in this way in many (reliable) sources. In this case, it is preferable to leave the opening sentence as it stands. Axl ¤ [Talk] 08:39, 1 September 2009 (UTC)

Hm, I wonder if we can clarify somehow, without losing the flow?

• Current, "Oxygen toxicity is a condition resulting from the harmful effects of breathing..."

• How about, "Oxygen toxicity refers to the harmful effects caused by breathing..." ?  Chzz  ►  01:28, 4 September 2009 (UTC)

The first sentence in an article ought to define what something is, where possible. I don't think "refers to" does the job. I can see you think that removing the word "condition" makes things clearer. I think the opposite. If our sources can call the condition "oxygen toxicity", why shouldn't we? Thinking about what our sources use, perhaps we should state "Oxygen toxicity or oxygen poisoning is a condition ..."? --RexxS (talk) 03:03, 4 September 2009 (UTC)

Quite simply, we should not start with "OT is a condition" because it is not; that assertion is factually incorrect. The fact that some RS use the term incorrectly does not mean that we should. I do not currently have access to a good dictionary, and would be interested to see the OED entry on it, but even looking online I can find several dictionaries that support my assertion that the term describes an affect and not a condition;

• "Oxygen Toxicity This is the reaction of the body to extremely high oxygen levels." "Scuba diving", re-quoted on babylon.com

• "Oxygen toxicity A toxic effect in a living organism caused by a species of oxygen." McGraw-Hill Concise Encyclopedia of Bioscience, quoted on thefreedictionary

• Toxicity resulting from excessive exposure to gaseous dioxygen" Oxford dictionary of biochemistry and molecular biology

I hope that this helps illustrate my concerns; I'm not arguing for the sake of argument, but instead I feel that the very first sentence of this featured article is factually incorrect.  Chzz  ►  01:09, 24 September 2009 (UTC)

I sympathise with your concerns, but don't share them. I can see that "toxicity caused by oxygen" may not technically be a medical condition, but I believe that - in the absence of any other word for it - reliable sources use the phrase "oxygen toxicity" for the condition. What else is the condition caused by an excess of oxygen called? MeSH, in particular, indexed the condition from 1966 to 1994 as "oxygen toxicity" before replacing it with the broader "hyperoxia". In contrast with the dictionaries you quote, please consider:

• "oxygen toxicity: A condition resulting from breathing high partial pressures of oxygen" oxygen toxicity - definition of oxygen toxicity in the Medical dictionary - by the Free Online Medical Dictionary
• "oxygen toxicity: A condition resulting from breathing high partial pressures of oxygen" Oxygen toxicity: Definition from Answers.com (quoting The American Heritage Stedman's Medical Dictionary)
• "Central nervous system oxygen toxicity: High oxygen levels which affects the central nervous system. The condition can occur during deep dives with fatal consequences" Central nervous system oxygen toxicity Symptoms, Diagnosis, Treatments and Causes - WrongDiagnosis.com

And others

It is not our place to decide on the factual accuracy of the usage of terms from our sources. Our job is simply to report what the sources say. --RexxS (talk) 16:31, 24 September 2009 (UTC)

SCUBA

"Scuba divers [...] must have specific training to be allowed to purchase and use such gases for breathing."

In which country? In many places, anyone can buy Oxygen. It is true that, for example, a PADI diveshop will not supply enriched air to divers unless they present evidence of their Nitrox course, but that is not the same thing at all.

What are 'such gases'?

 Chzz  ►  22:27, 31 August 2009 (UTC)

"Such gases", (I had hoped) refers to "breathing gases containing up to 100% oxygen". Perhaps you can suggest a better formulation for the sentence? Here in the UK, anyone can buy 100% oxygen for welding, but not for breathing. The welding gas was all we could get 20 years ago when we had to mix in the garage. I don't know of anywhere where you can get a cylinder filled without restriction with a mix (i.e. "breathing gases containing up to 100% oxygen") - other than air of course! These sort of restrictions may not apply in some countries, but you'd need a cite to contradict ref 120, if you felt that should be mentioned. --RexxS (talk) 00:35, 1 September 2009 (UTC)

For clarification, here is the full sentence that Chzz is unhappy with:-

"Scuba divers use breathing gases containing up to 100% oxygen and must have specific training to be allowed to purchase and use such gases for breathing."

In my opinion, the sentence would benefit from a comma:-

"Scuba divers use breathing gases containing up to 100% oxygen, and must have specific training to be allowed to purchase and use such gases for breathing."

From "Society and culture": "In order to buy nitrox, a diver has to show evidence of such qualification.[121]" Reference 121 is the British Sub-Aqua Club (2006): "The Ocean Diver Nitrox Workshop". This reference mentions risk of "DCI" in several places, but unhelpfully never expands the abbreviation. I was unable to guess what this actually stands for. After searching the internet, I suppose that this means "decompression illness"?

The reference indicates: "Unless you have attended a skill development course in the use of nitrox, you will not have access to breathing gases where the oxygen content is greater than air." I couldn't find an explicit statement indicating that evidence of qualification is required to purchase these gases.

When I read the offending sentence, it is clear to me that "such gases" are "breathing gases containing up to 100% oxygen".

In summary, the sentence would benefit from a comma as I noted above. However, of greater concern is the assertion that specific training is required to purchase the gases. I would like to see a more robust source. Also, it should be made clear if this is a worldwide requirement (unlikely) or imposed only in certain countries.

Axl ¤ [Talk] 09:12, 1 September 2009 (UTC)

Thanks for the suggested comma, Axl, I've inserted it. I do agree that we could do with a more robust source for what is common knowledge among scuba divers, but I found it difficult to find that in print. Although I do know that in all countries where I've dived, I've needed evidence of a nitrox qualification to be allowed to get a cylinder filled with nitrox. All of the dive agencies agreed that at the DAN Workshop 2000, as well as the requirement that the gas is analysed by the end-user and signed off - concerns about liability, of course. Obviously I'm making the synthesis that a training course is needed to obtain the nitrox qualification. I'll see if I can find more sources online. --RexxS (talk) 16:46, 1 September 2009 (UTC)

Well, not WP:RS, but here's a flavour of what you get from a Google search for "purchase nitrox":

• http://www.ezdivers.com/id32_m.htm (Cyprus, PADI) "Only certified Nitrox divers may purchase nitrox from dive centres."
• http://www.infohub.com/outfitters/2462.html (Oman) "You will also need a Nitrox Certification card to purchase Nitrox gas. To fully understand the benefits of using Nitrox it is important to receive proper training."
• http://oceandiving.co.uk/content/view/13/28/ (UK, TDI) "Only certified Nitrox divers may purchase nitrox from dive centres."
• http://www.global-scuba.com/specia.html (Oman, BSAC/NAUI/PADI) "You will also need a NITROX Certification card to purchase NITROX gas. To fully understand the benefits of using NITROX it is important to receive proper training."
• http://www.eastcoastdiverllc.com/Fills%20&%20Rentals.htm (USA) "To purchase NITROX fills, divers must be 'NITROX Certified'."

and so on. It looks like there's a common wording used by some PADI centres, so I bet there's a source somewhere. Any PADI divers that can find it? --RexxS (talk) 18:10, 1 September 2009 (UTC)

P.S. Yes, DCI is Decompression illness, which is just a catch-all for Decompression sickness (DCS) and Arterial gas embolism (AGE). They get lumped together for scuba medics, since the differential diagnosis is tough, while the first aid treatment and subsequent management are identical. --RexxS (talk) 18:10, 1 September 2009 (UTC)

I agree with the P.S. completely; before I got to it, I was about to write something v similar.

Regarding purchase of enriched air etc, allow me to try to clarify something. In PADI manuals and other such sources that you'll cite, certain things are stated as 'fact' - you must always dive with a buddy, you must not exceed a depth of 40m, you must not use enriched air mixtures without undertaking specialized training. The reality is that these are PADI guidelines, and infact PADI only provide training courses; there are actually no 'official requirements' for diving, other than local law. PADI regulations only cover a PADI course. As an instructor, I adhere to their standards; if I did not, then PADI could remove my instructor status - however, I would not be locked away for it, unless I did something to endanger lives, and this breached a local law. I hope I am explaining this; the point here is, in many countries there is nothing illegal about purchasing or breathing enriched air. Certain diving associations (including PADI, NAUI, BISAC, et al.) impose their own 'rules'. Thus, a PADI-affiliated dive-shop will refuse to sell an enriched air mixture to a customer who cannot provide evidence of their NITROX cert, which is a card (although they will often also look up your reg number online and accept that) - this could be sourced from PADI manuals.

I was seeking clarification in the prose to state the facts, and it is somewhat misleading to assert that ""Scuba divers [...] must have specific training to be allowed to purchase..." etc. That is 'according to PADI (and others), it is not a legal requirement. Perhaps something like "Diver certification orgs (PADIref, NAUIref) require their members to undertake additional training before they are supplied with..." etc?  Chzz  ►  01:23, 4 September 2009 (UTC)

Ok - thanks for clarifying. I can see what you're getting at now. There's an ambiguity particularly in the use of the word "must" - it can imply a legal requirement that we all agree doesn't exist. I suppose I was trying to write as concisely as I could something like "If divers don't have a recognised training qualification in nitrox, they are very unlikely to be able to find anyone who is willing to sell them a nitrox mix", which I hope we could all agree is fact. I really don't like the spaghetti of lists of diving organisations, so wouldn't be keen on a formulation that relied on naming them. I would also prefer to state that it is a specific training that is required for certification; for example, AOW is "addition training" but insufficient to allow a diver to purchase nitrox. IMHO, the real restriction on buying nitrox is that vendors won't risk the liability that could arise from flouting the general agreement on who should be allowed to purchase nitrox. Would "Scuba divers may breathe gas mixtures containing up to 100% oxygen, but vendors will refuse to sell such mixes to divers who do not have specific training in using them." meet your concerns? --RexxS (talk) 02:49, 4 September 2009 (UTC)

I hope that any comment about restriction of sales is accompanied by a robust source. Thanks. Axl ¤ [Talk] 09:45, 4 September 2009 (UTC)

No, I do not agree that it is a fact, that non-nitrox-certified divers are "unlikely" to be able to get nitrox. Certainly not without substantial reliable sources. From my own experience, I am aware of many places around the world where Nitrox is supplied without the credentials. This is precisely why facts need reliable sources, and we must always be careful in not making assumptions. If you wish to avoid excess detail, perhaps it could be worded as "divers should have special training before using Nitrox" - which might be a bit vague, but at least it is verifiable.  Chzz  ►  12:33, 12 September 2009 (UTC)

Sorry, I didn't realise you were talking from personal experience. My experience is the opposite. I'm quite happy with detail in the body of the article so we ought to present both opinions: "... but some (many?) vendors have a policy of refusing to sell such mixes to divers who do not have specific training in using them;<my refs here> while others will allow nitrox to be sold without evidence of qualifications.<your refs here>" Then I insert my admittedly weak sources (given above) and you provide the sources that back up your experience. It is suggested in WP:Reliable source examples#Use of electronic or online sources that These media can be used for primary data about the organization's view of itself and may have clear bias related to commercial interests. so have to be treated with caution. However, examples of shops stating a policy is surely evidence that some shops have that policy. --RexxS (talk) 18:36, 12 September 2009 (UTC)

The sources that you are citing assert the fact that certain affiliated dive-shops should only supply Nitrox to trained divers, it does not assert that they actually do.  Chzz  ►  01:11, 24 September 2009 (UTC)

There's no mention of the word "should". The sources I quoted above demonstrate that certain dive shops have a policy of only selling nitrox to nitrox-certified divers. I have yet to see a source showing that any dive shop has a different policy. --RexxS (talk) 16:38, 24 September 2009 (UTC)

I've replaced the ambiguous "must have specific training ..." in the lead with "should have specific training ...". In the section "Society and culture", would it be more accurate to state "In order to buy nitrox, a diver normally has to show evidence of such qualification"? --RexxS (talk) 14:28, 26 September 2009 (UTC)

Causes

• "Oxygen toxicity is caused by exposure to oxygen at partial pressures greater than those that the body normally tolerates."

This is meaningless, it is like saying that "Head pain is caused by exposure to baseball bat blows that are harder than those that don't hurt"

The rest of this para is very vague too; "underwater diving" is an odd term, and "particularly to premature infants." is worryingly WP:WEASEL.

"Divers breathing [...] nitrox, can similarly suffer a seizure at shallower depths, should they descend below the maximum depth allowed for the mixture."

This is similarly vague, and it is not what guidelines (e.g. PADI) say - there are no precise points at which it becomes a critical effect, because there are so many factors to be taken into account, such as age/weight/fitness/pre-existing conditions and that sort of thing. The guidelines are very clearly worded as just that - ie 'nobody can say for sure, but if you stick to these recommendations, it is highly unlikely that you will have problems'. I therefore think that this needs clarification.

 Chzz  ►  23:34, 31 August 2009 (UTC)

Sorry, I disagree. Oxygen toxicity is caused by exposure to oxygen at partial pressures greater than those that the body normally tolerates. clearly does have a meaning. If you mean it is imprecise, then I agree; it is the introductory sentence to the section, which is then expanded with more precision in the sub-sections below. The partial pressures tolerated are spelt out below - or they were, before some of them were removed today.

There is nothing odd about the phrase "underwater diving" - it disambiguates between diving (as in scuba, surface-supplied, etc.) and the sport of leaping into the water from a height. See Diving. I simply cannot see your objection to the phrase the provision of supplemental oxygen, particularly to premature infants. Read the sources: they demonstrate quite clearly that the problems of BDP and ROP are primarily neonatal concerns - and that those conditions are the commonest concerns of supplying supplemental oxygen.

The fact is that CNS toxicity is a real concern for divers should they breathe a mix below its MOD. I agree 100% that there is no precise ppO2 beyond which "There be Dragons", but the huge variability of individual and day-to-day tolerance means that a diver could experience a seizure at ppO2 beyond what are considered safe limits. That's what the sentence says. It's not vague. What it states is true and may be easily verified. The US Navy set a ppO2 limit of 1.2 bar, the recreational diving organizations agreed a 1.4 bar limit, extended to 1.6 bar when resting (during decompression stops). PADI, just like the other organisations, is not going to run the risk of liability by saying that MOD can be safely exceeded. While it is true that the limits are undoubtedly conservative, the possible cost of exceeding those limits far outweighs any conceivable benefit of doing so. Take a look at DAN Nitrox Workshop Proceedings 2000, page 183 onwards and you'll see how PADI arrived at its "guideline", particularly see page 190 where Richard Moon says, "Simply make the point that there may be people who are more susceptible for whom 1.6 atm is not appropriate, but at present there is no reliable way to identify such individuals." If that august group were worried about having a safe limit, I'd hope you'd allow this article to mention the possibility of seizures if MOD is exceeded? --RexxS (talk) 01:43, 1 September 2009 (UTC)

Addendum: I probably owe you an apology on the first point, if your quibble is with the those that the body normally tolerates part. We may be coming to this from different viewpoints. Mine is that O2 is inherently poisonous to biological systems, but that organisms have defences that allow them to tolerate that toxicity as long as the ppO2 is not too great. That is what I think was behind that phraseology. Perhaps those to which the body is normally exposed would be an acceptable substitute? --RexxS (talk) 01:52, 1 September 2009 (UTC)--RexxS (talk) 01:52, 1 September 2009 (UTC)

I agree with RexxS. It is reasonable to change the sentence to "Oxygen toxicity is caused by exposure to oxygen at partial pressures greater than those to which the body is normally exposed."

I don't regard "underwater diving" as an "odd term". Wikipedia has an article on it: "Underwater diving", if that's helpful. However I think that it would be more useful to use the term "scuba diving" in the sentence.

I strongly disagree with Chzz's assertion that the phrase "particularly to premature infants" is "weasel". This phrase is certainly not intentionally evasive, ambiguous or misleading. There are references in the subsections "Pulmonary toxicity" and "Ocular toxicity" explicitly describing the increased risk in premature infants.

"Divers breathing [...] nitrox, can similarly suffer a seizure at shallower depths". "This is similarly vague ... - there are no precise points at which it becomes a critical effect". Exactly! The sentence is deliberately vague (using the word "can"), specifically because there are no such precise points. The sentence is true, clear in meaning and appropriately referenced. It does not need to be changed.

Axl ¤ [Talk] 09:53, 1 September 2009 (UTC)

Thanks for that phrasing, Axl. I've made that amendment in the article. Chzz was right that it could be improved.

I would have used "scuba diving" instead of "underwater diving", but that would exclude surface supplied diving - mainly commercial diving, and not scuba - where oxygen toxicity is also a very real concern. I actually considered "scuba and surface supplied diving", but rejected it as too clumsy for the lead, compared to "underwater diving". --RexxS (talk) 16:54, 1 September 2009 (UTC)

Okay, thanks RexxS. Axl ¤ [Talk] 17:48, 1 September 2009 (UTC)

How about, Oxygen toxicity is caused by exposure to high levels of oxygen ? Similarly vague, but at least it's not just 'stating the obvious'. My point was, the original is the linguistic equivalent of XXX poisoning is caused by exposure to more XXX than normal., e.g. Cyanide poisoning is caused by exposure to more Cyanide than the body normally tolerates. Yes, it's correct, but it adds no useful information.

It is important to remember that 'partial pressure' is a theoretical, abstract concept; a useful working model and nothing more. At sea-level, in normal conditions, each breath that we take contains approx. 21% O. We can refer to this as a 'partial pressure of .21', ie .21 is the fraction of the whole content of a lungful that is made of O. Underwater, at 10 metres depth, the pressure is approx. doubled - thus, each time we inhale, it takes double the quantity of air to fill our lungs. Therefore, with every breath, we inhale twice as much O (and twice as much of everything else) - so, it is equivalent to breathing a mixture that contains 42% O at sea-level, ie it has the same effect. At 20m it is 3x, 30m 4x, etc. At 60m, 7x0.21 = 1.47, and that may be considered an excessive amount, likely to cause problems. Note that this is the equivalent of breathing a mixture which contains1470% O, which is a good trick...hence, it is a theoretical model only.

With regards to "particularly to premature infants" - I remain unconvinced that we have a reliable source to assert this; certainly it can occur in infants, but it can also occur in older people who regularly breathe pure O. Perhaps we can find some information on that.  Chzz  ►  03:07, 4 September 2009 (UTC)

Why would it be better to start the article by talking about what causes it, rather than telling the reader what it is? Look at WP:LEAD#First sentence: The article should begin with a short declarative sentence, answering two questions for the nonspecialist reader: "What (or who) is the subject?" and "Why is this subject notable?". The point is that, to a lay reader, it is not obvious that oxygen becomes toxic at elevated pressure, or that this condition is important in many fields. The article starts out by stating this and the information is clearly useful. You do no service to the reader by trying to remove that information because of some semantic quibble that oxygen toxicity is not a medical condition.

Partial pressure, like all all concepts in physics, is indeed a theoretical construct. That makes it no less useful. In this case the partial pressure of oxygen relates directly to the number of molecules of oxygen per second striking the surface of its container (such as the lungs). It is no surprise then, that the effect of the oxygen is most strongly related to its partial pressure. You may find it useful to distinguish between the fraction of oxygen in a mix (21% in air) - a dimensionless ratio - and the partial pressure of oxygen (0.21 bar in air at sea level) - a measurement of pressure, using units of pressure. Interchanging the two causes the confusion of thinking that breathing air at 60 metres somehow equates to it containing 1470% oxygen! --RexxS (talk) 17:36, 4 September 2009 (UTC)

From "Causes", "Pulmonary toxicity", paragraph 3: "Preterm newborns are known to be at higher risk for bronchopulmonary dysplasia with extended exposure to high concentrations of oxygen."

"Causes", "Ocular toxicity":

Main article: Retinopathy of prematurity

"Hyperoxia may be a contributing factor for the disorder called retrolental fibroplasia or retinopathy of prematurity (ROP) in infants."

Here are quotes from "Handbook of Neonatal Intensive Care":-

"CLD/BPD [Chronic lung disease/bronchopulmonary dysplasia] is an iatrogenic disease caused by oxygen toxicity and barotrauma resulting from pressure ventilation.... Developmental immaturity is of principal importance in the etiologic picture of CLD/BPD. Premature births alone may have a significant effect on pulmonary development, because prematurity results in differences in the development of small airways. As a result, premature infants are more susceptible to additional damage to the small airways from oxygen, ventilator pressure, fluids, and circulatory overload."

"Since the 1950s researchers have recognized the association among oxygen administration, prematurity, and subsequent retinal changes often resulting in blindness. Severe restriction in the use of oxygen with premature infants resulted in less ROP, but also in increased morbidity and mortality rates."

We already have three good quality reliable sources showing the connection between prematurity and oxygen toxicity (references 1, 2 & 3 above). The textbook that I quoted is representative of the medical literature. The text of the book itself has numerous references. Every textbook on paediatrics/neonatology states the connection.

Axl ¤ [Talk] 10:28, 4 September 2009 (UTC)

Re. premature babies, I think you are misunderstanding my criticism; I'm sorry, I will try to explain it better.

Let's try an example, imagine all these 'facts' are covered by sources; a) The Sausage Spider is poisonous, b) Babies are more vulnerable to poison. We cannot, therefore, conclude that c) the Sausage spider particularly affects babies. Of course, it will affect them, and they are likely to suffer more than adults - but that doesn't mean that they're the most statistically significant affected group.

I am not questioning whether Oxygen toxicity is relevant to infant prematurity, I am merely saying that it is vague to use the term 'particularly' (used several times within the article). It's not been quantified.

For example, it currently states that, Pulmonary and ocular damage are most likely to occur when supplemental oxygen is administered as part of a treatment, particularly to newborn infants - please show a reference that states this fact, ie that this form of damage is most likely to occur in newborns.

I hope that this clarifies; I an not doubting a connection between premature infants and difficulties with this kind of lung problem (as well as many others) - I am questioning whether it is fair to say that O2 tox is particularly a problem in newborn babies, as opposed to a problem in divers, old people, etc - at least, without some source that compares injury and death-rates.  Chzz  ►  13:00, 12 September 2009 (UTC)

Thanks for the clarification. Perhaps a couple of reviews will assuage your concerns. Clare Gilbert found this:

Studies undertaken in neonatal intensive care units in industrialised countries have shown that up to 60% of LBW babies develop ROP, which rises to 72% in ELBW babies. The proportion of VLBW babies which develop Stage III ‘plus disease’ and subsequent blindness can be as high as 11 % and 8% respectively.

and Tapia et al found this:

The total number of ventilated newborns was 200, incidence of BPD was 9.5% (19/200) and lethality for BPD was 5.2% (1/19). The incidence of BPD increased progressively with decreasing BW, reaching 37.5% in infants less than 1,000 g (p less than 0.001 chi 2).

Those rates of incidence are not found in the general population. BPD for example is classified as a "rare disease" - see here. The NIH states Bronchopulmonary dysplasia, or BPD, is a serious lung condition that affects mostly babies who ... [n]eed long-term breathing support and oxygen, and quotes an annual rate of 1 in 54,400 of the population for the USA. I would hope that "Retinopathy of Prematurity" is self-evidently a condition affecting premature newborns. I can see that "Pulmonary and ocular damage" is not identical to "BPD and ROP", but if there are any other common manifestations of these types of damage, I've yet to find a source that says so. --RexxS (talk) 19:25, 12 September 2009 (UTC)

In investigating this issue, I found the following;

"In the past, supplemental oxygen was thought to be a contributing factor to the development of ROP. Currently, the role of supplemental oxygen is not clear, with some studies even suggesting that insufficient oxygen may increase the severity of the disorder." - Rudolph's fundamentals of pediatrics 2002, (available on Google Books)

From searching Google Scholar, I think that the matter is far from clear-cut, but I'm unable to view most of the scholarly articles because they require subscriptions etc.  Chzz  ►  00:51, 14 September 2009 (UTC)

I wouldn't quibble with the statements made in Rudolph's fundamentals of pediatrics, but would caution against drawing unwarranted conclusions from them. The role of O2 in ROP is indeed unclear, but the fact that elevated ppO2 can induce ROP is not disputed. You can get a flavour of the state of current knowledge by scanning PubMed abstracts and summaries. I found these quite quickly:

• Oxygen-induced retinopathy in the rat model
• Pathogenesis of retinopathy of prematurity and possible preventive strategies
• Animal models of oxygen-induced retinopathy
• Pathogenesis of retinopathy of prematurity
• Regulation of vascular endothelial growth factor by oxygen in a model of retinopathy of prematurity

If you're interested in the topic, then PubMed shows links to lots of similar articles - it's a popular topic for investigation since a better understanding of the pathophysiology could lead to better preventative strategies or treatments. --RexxS (talk) 02:31, 14 September 2009 (UTC)

Boldly marked

The caption on the image File:Cylinder mod.jpg (shown here) read "The label on the diving cylinder shows that it contains oxygen-rich gas (36%) and is boldly marked with a maximum operating depth of 28 metres." I removed the word 'boldly', but it was reverted here, with the edit summary "Yes it is boldly marked - http://dictionary.reference.com/browse/boldly?r=75 "striking or conspicuous to the eye"".

I am aware of the word 'boldly', but I do not consider this specific label to be particularly striking or conspicuous; this is a non-neutral turn of phrase. In reality, this is a poor example photograph; it would be better if we could obtain a picture with a 'typical' green-yellow Nitrox label; some (presumed non-free) links are [3] [4].

In any event, regarding the current photo, I disupte the assertion that the label shown is boldly marked.  Chzz  ►  03:07, 4 September 2009 (UTC)

The point of marking a cylinder containing anything but air is that if you use that cylinder too deep, you run a real risk of oxygen toxicity - not a trivial concern for any deep diver. It is absolutely imperative that the cylinder contains the most important information marked as clearly as possible - and the most important piece of information is the maximum operating depth. Nothing else comes close to mattering, so any thinking diver makes sure that the MOD stands out from anything else marked on the cylinder and that it is easily visible. I find it astonishing that you don't believe the MOD marking (28) on the photograph does not stand out; even more that you would suggest those other two images where the information is presented so badly. Nobody but a suicidal idiot would use such markings on vital life-support equipment. When I'm doing a scheduled gas switch from trimix to EAN36 at the 27 metre stop, I need to be able to see quite unambiguously on a cylinder that's slung under my left arm that its MOD is 28 m, not fighting to swing it round and get it close enough to read such a ridiculously small inscription. May I ask what you think is poor about the photograph I took? Is the photography not up to standard? If so, feel free to take one yourself. Or do you think that it's more important to show a prettily-coloured printed label than a hand-written one that does the job a hundred times better? It's not the label that is meant to be conspicuous, it's the marking of MOD on it that is. --RexxS (talk) 18:05, 4 September 2009 (UTC)

I was not criticizing the photo in that manner, nor were the two links I added actual 'suggestions for replacement'. I just thought that it might be clearer to the reader to show that Nitrox tanks generally 'stand out' due to the distinctive green and yellow. The vast majority of recreational divers using Nitrox are using it as their only tank, thus the issue of tank-swaps does not arise. I do not agree that the hand-written note does a better job than such a distinctive coloured label, at least in terms of making the tanks stand out clearly from others. Do you really consider all PADI Nitrox divers to be suicidal idiots?  Chzz  ►  18:22, 7 September 2009 (UTC)

I agree that the green/yellow marking makes a nitrox tank stand out, but here in the UK, my local dive shops use the white band with green/yellow markings, so I that's all I had to photograph. Personally, I don't use nitrox much as a back-gas, as I'm either instructing in less than 24 metres (80 ft) or diving at considerably greater depths. I do take your point though - it would be nice to have an obviously marked nitrox tank with an extra label conspicuously showing the MOD; it's just that my gear doesn't fit that bill. Obviously I consider that making the MOD stand out is the important point, so you can see why I prefer the photo I took. If I can find someone in my club with a nitrox cylinder that's nearer to what you would like, I can mark its MOD with one of my waterproof labels, photograph it, and replace that picture. As for PADI: well I'm a senior member of another diving agency (with considerable respect for much of what PADI does), so I'm not in the business of criticising other agencies' practices. Nevertheless I don't think that any diver is well-served by not making a cylinder's MOD as visible as possible. I accept that others may not attach the same importance to it as I do. --RexxS (talk) 21:23, 7 September 2009 (UTC)

A photo showing both would certainly help. I guess my concern is over 'typical recreational diving'. As PADI mostly uses 32% and 36% mixes, and usually doesn't exceed 30m, them MOD isn't really the important thing. On a 'typical' PADI dive expedition, It is very unlikely that anyone on the boat is going to dive below 30m - and if they do, they'll be experienced, and won't be silly enough to mix up tanks. Also, I suppose, we're more concerned with the distinction between Nitrox and non-nitrox tanks than the exact MOD; the Nitrox divers will check the details of their own tanks (with an oxygen analyzer), and put their name on their tank. (And, in most cases, they'll prob all be 32% anyway)  Chzz  ►  13:17, 12 September 2009 (UTC)

Questions re. 'Society and Culture' section

• "technical divers use nitrox containing up to 80% oxygen, or pure oxygen gas" - what does this mean? 80%, or 100%, which?

• Para beginning "Since the late 1990s" - ie oxygen bars, potential benefits, etc - does this really have anything to do with O toxicity?

 Chzz  ►  04:12, 4 September 2009 (UTC)

• It means either one or the other (hence the use of the word 'or'). In training it is not unusual to use EAN80 ("nitrox containing up to 80% oxygen"). Once a diver is comfortable holding a 6 metre stop, then 100% O2 is preferred. As it has been pointed out numerous times, if it's 100% O2, then there's no nitrogen and it can't be called nitrox. Would technical divers use pure oxygen or nitrox containing up to 80% oxygen be clearer?

Yes, that would be clearer; it's the odd juxtaposition of "80% or pure" that was awkward.  Chzz  ►  17:49, 7 September 2009 (UTC)

P.S. I'm also a bit concerned about the part before that; "use nitrox, a breathing gas containing up to 40% oxygen" - this makes it sound like "up to 40%" is a definition of Nitrox, and that is then contradicted by the next part. Maybe an explicit definition of Nitrox at the start of the para would help? I'm not quite sure how to fix it, but I think clarification is necessary. It's not really 'fair' to say that technical diving is not recreational diving either; the phrase "recreational" is really to distinguish it from commercial diving. Most tech diving is also for fun, for recreational purposes. Let me know if you have any ideas, or if not, I'd be happy to dig out some books and try to think of a suitable phraseology.  Chzz  ►  17:54, 7 September 2009 (UTC)

Agreed. It's been bugging me as well. I originally used the wording "Recreational scuba divers now commonly use nitrox, a breathing gas containing up to 100% oxygen" in the lead, but it continually attracted pedantic comments like "there is no NITRogen in 100% OXygen, so it cannot be called NITROX". Rather than keep pointing out that "up to 100%" should be taken as shorthand for "up to, but not including, 100%" and reverting, I gave way and changed the lead, removing the word nitrox. Unfortunately I then made the mistake of mentioning nitrox in the "Society and Culture" section (as it was meant to refer to nitrox use becoming part of mainstream scuba culture). This then generated numerous "improvements" which wanted to distinguish between "recreational nitrox (up to 40%)" and "technical nitrox (up to 80%)" for reasons I couldn't see. I gave in at that point and left them to it. I'd be most grateful if you or anyone else could clean up that mess, as I no longer have the will to try. --RexxS (talk) 22:04, 7 September 2009 (UTC)

Addendum: I found I had enough energy to attempt a small modification. It no longer attempts to define nitrox (a difficult task in itself), but assumes that it's a breathing gas (as the divers now breathe it rather than use it). It might be sufficient to meet your concern, but if not, please pitch in if you can see a better wording. --RexxS (talk) 22:32, 7 September 2009 (UTC)

• I agree that oxygen bars have only a tangential relationship to oxygen toxicity. Nevertheless, the CDER has expressed a concern about oxygen bars that some individuals with pre-existing conditions may be at increased risk of pulmonary oxygen toxicity. I felt it was worth reporting that as an example of possible unexpected oxygen toxicity in common culture, but much of the background "padding" could be removed from the article without any real loss. --RexxS (talk) 18:21, 4 September 2009 (UTC)

My gripe with this was that the section on it makes no mention at all of oxygen toxicity; the CDER recommendation is regarding abstinence in the case of pre-existing conditions, but is this advice specifically given to avoid oxygen toxicity?  Chzz  ►  17:49, 7 September 2009 (UTC)

I think it fits the definition of "the harmful effects of breathing molecular oxygen (O2) at elevated partial pressures", so I'd defend its inclusion. The most relevant bit of the CDER article is:

People with some types of heart disease, asthma, congestive heart failure, pulmonary hypertension, and chronic obstructive pulmonary diseases, such as emphysema, need to have their medical oxygen regulated carefully to oxygenate their blood properly, says Purucker. "If they inhale too much oxygen, they can stop breathing."

My impression from that is they are concerned about CO2 retention, which is mentioned in the "Classification" section. This article did contain a lot more about COPD exacerbation, but it became WP:UNDUE so I made a spinout called "Effect of oxygen on chronic obstructive pulmonary disease". Patel et al. 2003 (current ref number 14) include "Carbon dioxide narcosis" in the classification section of their review of oxygen toxicity, and describe the symptoms & mechanism as above, so we have at least one reliable source that supports this inclusion. --RexxS (talk) 22:04, 7 September 2009 (UTC)

That sounds more like Purucker might talking about a separate issue. The 'breathe' reflex is (mostly) triggered by a build-up of CO₂ rather than a lack of O, and when O levels are elevated, there may not be time for the CO₂ to build up, which can cause unconciousness. That problem is also well-known to divers, but mostly free-divers, as Shallow water blackout. Unfortunately, that article is not very good.  Chzz  ►  12:49, 10 September 2009 (UTC)

No, it's the right issue. What happens is that some individuals with COPD or similar chronic problems become so acclimated to CO2 build-up, that the normal reflex (triggered by high blood pH) becomes dulled and non-functional. Then the weaker reflex that is triggered by low O2 actually becomes the dominant reflex in controlling breathing. If these individuals breathe elevated ppO2, then that reflex doesn't kick in until much later, and they don't breathe. This leads to the problems of acute hypercapnia. There's a concise description in the ref I gave above (Patel et al.) - in fact there are other exacerbating factors that Axl has described very well in Effect of oxygen on chronic obstructive pulmonary disease. I agree that shallow water blackout could do with improvement, but it's not quite the same effect as what Patel describes (SWB is caused by lack of CO2 in a normal individual: this problem is caused by excess of O2 in individuals lacking the normal CO2 reflex). Perhaps we could get together and collaborate on improving shallow water blackout sometime soon? --RexxS (talk) 16:13, 10 September 2009 (UTC)

Purucker is talking about exactly the same mechanism that RexxS is describing.

"When O levels are elevated, there may not be time for the CO2 to build up, which can cause unconciousness."

This is incorrect, both in CO2 retention due to COPD, and in shallow water blackout. The mechanisms involved are described in those articles.

Axl ¤ [Talk] 16:19, 10 September 2009 (UTC)

mnemonic

A mnemonic for O2 toxicity is VENTIDC ( visual symptoms, ear tinnitus, nausea, twitching and tingling, irritability, dizziness, convulsions ) Is this significant enough to add to the page?Doc James (talk · contribs · email) 19:39, 6 October 2009 (UTC)

Worth considering, as the Russian wikipedia includes it. However, WP:MOSMED#Writing style counsels against including mnemonics in medical articles:

Most mnemonics and rules of thumb are non-notable constructs that exist primarily for the purpose of helping medical students pass tests. Consider providing the information that these contain, without necessarily providing the artificial and distracting structure of the memory aids.

We already have VENTID (the alternative mnemonic) in the article Nitrox where it is introduced in the context of diver training, so may be more acceptable. If my personal opinion is worth anything, I never bother to teach it, since seizures reportedly occur more often without warning and VENTID isn't going to help most of the time. Just my 1.3p. --RexxS (talk) 21:24, 6 October 2009 (UTC)

I am not set on it one way or the other. I use it in that I will stop a HBOT dive if the person develops these symptoms. Doc James (talk · contribs · email) 03:23, 7 October 2009 (UTC)