Content deleted Content added
ce |
Citation bot (talk | contribs) Add: pmid, authors 1-1. Removed parameters. Some additions/deletions were parameter name changes. | Use this bot. Report bugs. | Suggested by Headbomb | #UCB_toolbar |
||
Line 18:
Haldane prepared the first recognized [[Decompression theory#John Scott Haldane|decompression table]] for the [[British Admiralty]] in 1908 based on extensive experiments on goats and other animals using a [[clinical endpoint]] of [[symptom]]atic [[decompression sickness]].<ref name="haldane" /><ref name=":0">{{Cite journal |last=von Lünen |first=Alexander |date=2006 |title=Goats and gases: "The Prevention of Compressed Air Illness" by Haldane et al--A commentary |url=https://pubmed.ncbi.nlm.nih.gov/17078317 |journal=Wilderness & Environmental Medicine |volume=17 |issue=3 |pages=195–196 |doi=10.1580/06-weme-lh-028 |issn=1080-6032 |pmid=17078317}}</ref> The model, commented as "a lasting contribution to the diving world", was published in the ''[[Journal of Hygiene]]''.
<ref name=":1">{{Cite book |
Haldane observed that goats, saturated to depths of {{convert|165|ft|m}} of sea water, did not develop [[decompression sickness]] (DCS) if subsequent [[Decompression (diving)|decompression]] was limited to half the ambient pressure. Haldane constructed schedules which limited the critical supersaturation ratio to "2", in five hypothetical body tissue compartments characterized by their halftime. Halftime is also termed [[Half-life]] when linked to [[Exponential decay|exponential processes]] such as [[radioactive decay]]. Haldane's five compartments (halftimes: 5, 10, 20, 40, 75 minutes) were used in decompression calculations and staged decompression procedures for fifty years.<ref>{{Cite journal |last=Wienke |first=B.R. |date=1989 |title=N2 transfer and critical pressures in tissue compartments |url=https://linkinghub.elsevier.com/retrieve/pii/0895717789904421 |journal=Mathematical and Computer Modelling |language=en |volume=12 |issue=1 |pages=1–15 |doi=10.1016/0895-7177(89)90442-1}}</ref>
Line 74:
* Diving period:
:* For short diving periods of less than seven to eight minutes with no repetitive dive: Haldane's experiments on goats showed that sudden decompression in less than a minute after exposures up to four minutes at {{convert|75|psi|bar|abbr=on}}, equivalent to {{convert|42|m|ft}} of sea water, goats did not develop any symptoms, even when exposures were raised to six minutes in some cases. This coincides with reports at that time from the Mediterranean of skilled Greek divers, diving to {{convert|30|fathom|m}} who, should their gear become entangled on the bottom, will cut their air-pipe and line, and blow themselves up to the surface in less than a minute.<ref name="haldane" />
:* With dives exceeding a few minutes or brief repetitive dives: Hill and Greenwood compressed themselves to {{convert|91|psi|bar|abbr=on}}, equivalent to {{convert|53|m}} of sea water, a very high pressure and risky experiment, and had bends after decompression. [[File:From Haldane's Book - N2 Saturation for different body tissues.jpg|thumb|The saturation curves of Hill and Greenwook's experiment for parts of the body]]The saturation curves of their experiment for parts of the body were published in 1908.<ref>{{Cite journal |
[[File:Haldane - Bends of fore-leg in a goat.jpg|thumb|220px|right|One of Haldane's bent goats. Note the bend in the left foreleg.<ref name=haldane>{{Cite journal |date=June 1908 |journal=The Journal of Hygiene |volume=8 |pages=342–443 |number=3 |pmid=20474365 |pmc=2167126 |last1=Boycott |first1=A. E. |title=The Prevention of Compressed-air Illness |last2=Damant |first2=G. C. |last3=Haldane |first3=J. S. |url=http://archive.rubicon-foundation.org/7489 |doi=10.1017/S0022172400003399 |access-date=12 May 2015 |archive-url=https://web.archive.org/web/20110324171946/http://archive.rubicon-foundation.org/7489 |archive-date=24 March 2011 |url-status=usurped }}</ref>]]
* Experiments continued on goats, and symptoms observed on goats were noted each time on appropriated schedule to record the presence of symptoms not the presence of bubbles:
Line 99:
==Further developments on Haldane's principles==
The 2:1 ratio proposed by Haldane was found to be too conservative for fast tissues (short dives) and not conservative enough for slow tissues (long dives). The ratio also seemed to vary with depth. The ascent rates used on older tables were {{convert|18|m/min}}, but newer tables now use {{convert|9|m/min}}.<ref>{{Cite journal |
* Haldane introduced decompression tables based on five tissue compartments with half times of 5, 10, 20, 40 and 75 minutes.
* The [[US Navy]] refined Haldane's tables and introduced a model with nine tissues. They also introduced calculations for half-times starting from 5 minutes and reaching up to 240 minutes.
Line 137:
Although Haldane's model remains the basis for [[Decompression practice|modern decompression tables]], Haldane's first decompression tables proved to be far from ideal.<ref name=":1" /> Haldane's equation is used by many dive tables and dive computers today, even though, a growing number of decompression models contradict its assumptions such as the
::* Asymmetry of saturation phenomena of inert gases (uptake and elimination),<ref name=":0" /><ref name=":2">{{Citation |last=Rusoke-Dierich |first=Olaf |title=Decompression Theory |date=2018 |work=Diving Medicine |pages=57–79 |editor-last=Rusoke-Dierich |editor-first=Olaf |url=https://doi.org/10.1007/978-3-319-73836-9_9 |access-date=2024-06-04 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-73836-9_9 |isbn=978-3-319-73836-9}}</ref>
::* Desaturation according to Hempleman's memorandum and those of Thalmann, taking into account circulating bubbles, VPM, [[Reduced gradient bubble model]].<ref>{{Cite journal |last=Hugon |first=J. |date=2014 |title=Decompression models: review, relevance and validation capabilities |url=https://pubmed.ncbi.nlm.nih.gov/25562945 |journal=Undersea & Hyperbaric Medicine |volume=41 |issue=6 |pages=531–556 |issn=1066-2936 |pmid=25562945}}</ref><ref name=":2" /><ref>{{Cite journal |
{{clear}}
| |||