Talk:Decompression sickness/GA1

GA Review[edit]

Article (edit | visual edit | history) · Article talk (edit | history) · Watch

Reviewer: Doc James (talk · contribs · email) 07:32, 30 July 2010 (UTC)[reply]

The first table[edit]

The table uses alternate colloquial and technical terminology in the first column. I feel it would be better if you used "the bends","the staggers", "the chokes" and "the niggles" or either "joints", "neuro", "lungs", "skin". Lean towards the first set as the next column has the anatomical locations. Doc James (talk · contribs · email) 07:32, 30 July 2010 (UTC)[reply]

The colloquial terms have fallen out of use nowadays, with the exception of "bends", which is now often used casually to refer to any type of DCS. For the purpose of the table, I think I'd prefer more technical terms for the overall type as used in Bennett & Elliott (my primary source), and use the more precise location to differentiate likely symptoms, e.g. brain or spinal chord within neurological. I've made amendments, so see what you think now. --RexxS (talk) 22:41, 31 July 2010 (UTC)[reply]

Just tweaked the syntax a bit. Looks good.Doc James (talk · contribs · email) 09:34, 1 August 2010 (UTC)[reply]

Society and culture[edit]

Only deals with coverage in the US. I know in Canada social medicine of course covers DCS as it does an other emergent / urgent health problem. It will cover transport within Canada from one health care center to the other if treatment is not available in the first. But will not fly one home from abroad for treatment. Doc James (talk · contribs · email) 07:40, 30 July 2010 (UTC)[reply]

Pretty much the same here in the UK. Although the EU-wide medical agreements may help pay for treatment/repatriation within the EU, I've not seen this tested. I do know that in Spain, it is normal to pay an extra few euros for recompression insurance. I will need to find good references for these though, before I can expand that section. Do you feel that expansion is necessary to meet GA criteria? I'm sure it would be needed for FA, but I was planning on expanding Society and culture along with examining In other animals (cetaceans are interesting) and Research as the next step, as it will require considerable further sourcing. --RexxS (talk) 22:53, 31 July 2010 (UTC)[reply]

No this is not necessary for GA just a suggestion. Doc James (talk · contribs · email) 09:22, 1 August 2010 (UTC)[reply]

Signs and symptoms[edit]

Wondering about this reference to altitude DCS: "Joint pain "the bends" accounts for about 60 to 70 percent of all altitude DCS cases" Since most DCS is SCUBA related should we not present these stats first?
This text is cannot be true as written "Seizures, dizziness, vertigo, nausea, vomiting and unconsciousness may occur, mainly due to labyrinthitis"
I am sure these would be more common to see with spinal cord injury not peripheral nerve "Urinary incontinence and fecal incontinence" Could you check the ref?

Doc James (talk · contribs · email) 09:40, 1 August 2010 (UTC)[reply]

1. don't have a good source to verify that most DCS is scuba-related. It is, thankfully, a rare occurrence among both divers and aviators. Two factors may confound comparisons between the two: (i) There is very little money available for research into diving-related DCS compared to altitude DCS – see Talk:Decompression sickness/Archive 1#Comments where User:Gene Hobbs (who works in the field) outlines the problem with this diff; (ii) The possible career implications for any aviator who acknowledges a DCS incident present a barrier to accurate reporting, and are likely to considerably distort any attempt to estimate incidence of altitude DCS. As you can see, these two factors oppose each other, so a definitive answer to which is most prevalent is probably impossible. Anyway, I have no problem with presenting them in whatever order you feel is best. The page when I came to it first was a mish-mash of information with little structure, and I think I tried to collate along historical lines: caisson disease; dive-related; altitude related – but may not have been totally successful.

2. You would know better than I what labyrinthitis actually is, but reading the article, it seems to encompass insults to the audiovestibular system. Since the ear has high blood perfusion, it is an organ with higher-than-average susceptibility to DCS. Bubble-related damage to the inner ear will almost certainly accompany a similar insult to the brain, so I can see why it was lumped together. For what it's worth, "Inner ear decompression sickness" (IEDCS) manifests rapidly with diziness, vertigo, nausea, and vomiting. It's particularly of interest as it is also the commonest symptom of isobaric counterdiffusion, which is the only DCS to manifest during an ascent, rather than after surfacing. I think you're right that the table needs improvement (more later). The problem with isolating symptoms of DCS is well illustrated by Francis & Mitchell (Bennett and Elliott p.580):

Too often, DCI is considered to have a number of discrete symptoms and signs when, in reality, it is a multisystem condition that may express itself in a variety of manifestations that can occur singly or in an overlapping fashion.

3. I agree, although one of my refs describes spinal and peripheral nerve together (again!), my primary ref (Francis & Mitchell, in Bennett and Elliott p.581) attributes incontinence to "spinal manifestations". I'm tempted to remove 'peripheral nerve' as a location since it's not really distinguished from spinal in any of my sources. I'd be happy to be guided by you on this. --RexxS (talk) 18:34, 1 August 2010 (UTC)[reply]

Cause[edit]

Why these locations? "DCS caused by ascent to altitude can happen without flying,<ref name="lippmann2007-79" /> when travelling to places such as the Ethiopian and Eritrean highland, which is 2,000 to 3,000 m (7,000 to 10,000 ft) above sea level, or the Peruvian and Bolivian altiplano (3,000 to 5,000 m (10,000 to 20,000 ft) above sea level)." Doc James (talk · contribs · email) 11:14, 1 August 2010 (UTC)[reply]

Although I did not provide these locations, I suspect that they were chosen as quite extreme examples of the scenario where a traveller may dive at the coast and then drive up to altitude, provoking DCS. In both cases, a drive of less than 40 miles from the coast can gain over 2,000 metres in altitude. If I were providing an example, I'd use one of my favourite dive locations, Tenerife, where I can do an lengthy deep dive in the morning and drive up Mount Teide (3,718 m) in the afternoon. I only did that once and turned back after about 15 minutes when I started feeling unwell and realised what was happening. I don't have any strong feeling about providing any particular examples, or any at all. Do you think they add value to the article? --RexxS (talk) 18:54, 1 August 2010 (UTC)[reply]

Well if they are notable within the literature we should keep them. If not than they should be removed.Doc James (talk · contribs · email) 06:58, 2 August 2010 (UTC)[reply]

I don't find all of those in the literature. However, that paragraph is a poorer duplicate of part of Predisposing factors, so I've been bold and simply removed it, as I think it is better treated as a risk factor than as a cause per se. --RexxS (talk) 19:12, 8 August 2010 (UTC)[reply]

Tables[edit]

First, thanks very much for your copyediting, James, I really value a fresh pair of eyes on these articles, as I feel very lonely on scuba-related topics, with only a tiny handful of regular editors for company.

Next, would you please take a look at User:RexxS/Accessibility. I'm currently working with Jack Merridew and others to improve awareness of the problems that rowspans cause to visually-impaired readers. It's a pet issue for me at the moment, and I believe quite strongly that replicating information in tables is sometimes necessary for improved accessibility, despite the aesthetic attraction of rowspans (which work fine for non-impaired readers). If I can convince you that there is a real point in this, I'd be grateful if you'd reconsider your edit that added the rowspans. In any case, any comments at User talk:RexxS/Accessibility would also be welcome.

I think I would like to amend the table somewhat, especially in the light of your comments above and the manifestations described by Francis and Mitchell. The 'peripheral nerve' symptoms essentially belong with 'spinal chord'. Would 'audiovestibular' be a more accurate descriptor for 'inner ear'? In the same frame, perhaps 'cutaneous' would be better instead of 'skin bends'? Francis & Mitchell use the following subheadings in their discussion: Neurologic, Musculoskeletal, Constitutional, Audiovestibular, Cutaneous, Lymphatic, and Cardiopulmonary. --RexxS (talk) 19:15, 1 August 2010 (UTC)[reply]

Sorry, some small points I forgot:

Normally, I wouldn't label a table, but it's referred to in Treatment as "(see Table 1)" – should I amend that to "(see table 'Signs and symptoms of decompression sickness')"?
I think the article is primarily written in British English (dmy for dates, metres not meters, depressurisation not depressurization etc.), so 'traveling' doesn't fit – 'travelling' is the correct spelling in en-gb.
Latest consensus at WP:Images#Image choice and placement says "Images should be large enough to reveal relevant details without overwhelming the surrounding article text. Similar types of images within an article often look appealing if they appear at the same pixel size". Although the latter part of the guidance urges some consistency, I believe the former is the overriding factor. I chose the size of File:Caisson Schematic.svg to allow a clear reading of the text. Setting it back to default means that 99% of readers will see it at 220px wide, and won't be able to read the text. MOS:IMAGES specifically gives this exception from default: "Images containing important detail (for example, a map, diagram, or chart), and which may need larger sizes than usual". I really think this should be applied in this case.

Would you have another look and see if you agree? --RexxS (talk) 20:07, 1 August 2010 (UTC)[reply]

Yes feel free to makes these changes. WRT images if they are set to default then I can adjust my default to 250 and they all line up nice and are bigger. There is a discussion to increase the default image size but concerns about processing speed.

WRT row span I do find that it makes the table easier to interpret for those with good vision ( who will be the majority ). Will read over the concerns for those with less vision :-) Doc James (talk · contribs · email) 07:04, 2 August 2010 (UTC)[reply]

No need for the table label now. Image resized - I can read the text/detail clearly now - does it look ok to you? I've rewritten the table to better reflect Bennett & Elliott. Until better screen readers are written, I've gone for maximum accessibility for visually-impaired, but it only costs one rowspan now. --RexxS (talk) 01:23, 3 August 2010 (UTC)[reply]

Isobaric counterdiffusion[edit]

Could use some expansion and explanation here as to how it works as it is a little counter intuitive.Doc James (talk · contribs · email) 08:11, 2 August 2010 (UTC)[reply]

I'll get some good refs tomorrow and expand it. It's because nitrogen is much more soluble than helium (even though it diffuses slower). Switching from a rich helium mix to a rich nitrogen mix at constant depth, you can temporarily oversaturate some tissues' total inert gas loading, and provoke bubbles - usually results in a hit in the inner ear. --RexxS (talk) 01:23, 3 August 2010 (UTC)[reply]

The Isobaric counterdiffusion article had the refs I needed, so I've gone ahead and expanded the section. Does that make more sense now? Steve Burton's webpage explains the phenomenon with worked examples, but I have resisted adding that level of detail. --RexxS (talk) 21:51, 3 August 2010 (UTC)[reply]

Grammatical changes[edit]

I have made a number of grammatical changes. Please check that I have not changed the intended meaning.Doc James (talk · contribs · email) 08:59, 2 August 2010 (UTC)[reply]

I've made a couple of copyedits: Prevention - Underwater diving better than scuba since it applies to all divers; I've revised the deco stop part so as not to assume the diver is breathing nitrogen - it applies to any inert gas.

A couple of other points:

the pathophysiology is believed, not known. We don't really know the mechanism of damage from bubbles - thrombosis, physical platelet damage, chemical change in the walls of the blood vessels - all of them are speculated, but no real proof of any (or a combination) has been show. Even in vitro tests are inconclusive. (I'll find you a ref if you're interested in this esoteric area.)
Regarding the 24/36 hour onset for diagnosis of DCS, Francis & Mitchell (in Bennett & Elliott, p.588) say "recreational divers may not notice subtle symptoms until one or more days after their last dive. Altitude exposure ... may be associated with even longer delays". Nevertheless, Ed Thalmann knows what he's talking about, so I'll happily accept the ref you found - although there's probably less than 1% of cases with symptom onset between 24 and 36 hours, so it's probably immaterial. --RexxS (talk) 01:23, 3 August 2010 (UTC)[reply]

Lets use both refs and say 24 to 36 hours.Doc James (talk · contribs · email) 04:03, 4 August 2010 (UTC)[reply]

The more I think about it, the more I think Ed Thalmann has got it right. There's no real contradiction between the views, because I think we're talking about the point beyond which DCS is no longer the most likely diagnosis ("Decompression sickness should be suspected ... particularly within X hours of diving"). I'm honestly much happier with X=24 than anything else as we're pretty certain that (absent any other provocative factors) 98% of all cases have onset of symptoms within 24 hours. --RexxS (talk) 19:31, 8 August 2010 (UTC)[reply]

Treatment[edit]

The treatment section dose not touch on a number of points such as the positioning of the person with the condition. I have sent you a paper to use to address this.Doc James (talk · contribs · email) 09:16, 2 August 2010 (UTC)[reply]

Thanks James, I'll have a good read tomorrow. To the best of my knowledge, the current recommendations for positioning are (i) for musculoskeletal symptoms only: whatever position is most comfortable; (ii) otherwise: supine (the Trendelenburg position was discredited years ago for DCS). But I agree some mention would benefit the article, although it's really only initial first aid, not actual treatment. --RexxS (talk) 01:23, 3 August 2010 (UTC)[reply]

I've had a good read of the uptodate article you sent – thanks very much. Paradoxically, it's out-of-date in the treatment section. The Tetzlaff, Shank & Muth perspective is dated to 2003 and looks as if it derives from advice such as O'Dowd & Kelley, 2000, which was indeed popular at the time. Although Durant's maneuver may assist with clearing "a large gas bubble obstructing the right ventricular outflow tract", such a diagnosis is near impossible at initial response, and routine use of any head-down position is problematical when dealing with suspected air emboli. This is discussed by Moon and Gorman (Bennett & Elliott, p.616) who observe although that early studies in rabbits (Van Allen et al 1929) showed a prophylactic effect, later studies (Butler et al 1988; Mehlhorn et al 1994) found little effect on distribution of intravascular air; and that a prolonged head-down position results in enhanced cerebral edema (Dutka 1990). They conclude that the supine position is preferable, which is confirmed in this online Merck manual: "Placing patients in the left lateral decubitus position (Durant's maneuver) or Trendelenburg position is no longer recommended" (Alfred A. Bove 2009). I'm not sure how much of this discussion is appropriate to include in the article. Any thoughts? --RexxS (talk) 15:20, 3 August 2010 (UTC)[reply]

I am not a big fan of Trendelenburg as you can see from my edits on its Wikipedia page. I agree with your research. Maybe say that at one point it was routinely recommended by is now only in rare circumstances. Trendelenburg decreases CNS perfusion and increases the risk of aspiration therefore has risks.Doc James (talk · contribs · email) 04:17, 4 August 2010 (UTC)[reply]

I've fleshed out the section to discuss broader aspects of management. --RexxS (talk) 20:28, 8 August 2010 (UTC)[reply]

Epidemiology[edit]

Any way we can make the line "The Sporting Goods Manufacturers Association has estimated that around 3.2 million divers participate at least once a year in the United States.<ref name="emed" />" more pertinent to DCS? Any publish literature taking the 2.8 per 10,000 and extrapolating it to the number of dives?Doc James (talk · contribs · email) 09:04, 2 August 2010 (UTC)[reply]

There's your ref: http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=65 which says "Decompression illness affects scuba divers, aviators, astronauts and compressed-air workers. It occurs in approximately 1,000 U.S. scuba divers each year." I think juxtaposing that with the 2.8 per 10,000 and ditching the Sporting Goods Manufacturers would make the points more appropriately than doing the arithmetic (3,200,000 divers * 2.8/10,000 dives = 896 {some divers dive more than once!}). What do you think? --RexxS (talk) 01:23, 3 August 2010 (UTC)[reply]