Asthma and Diving: some quotes from the medical experts
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With the recent discussion on Asthma and diving, I decide to finally begin a project Ive thought about for some time, providing a selection of quotes from sources on the subject. Since these quotes must be typed in, I may add some over time. Im focusing on the issue of gas trapping because there is so much misinformation floating around. The conference spent more time on testing and treatment issues.
The Source Im using is Are Asthmatics Fit to Dive?, the proceedings from an Undersea and Hyperbaric Medical Society Conference held on June 21, 1995, David H. Elliot Chairman and Editor. This is a source anyone seriously interested in asthma and diving should read, reprints are available here:
http://www.uhms.org/Publications/publicat.htm.
Dr. Elliot:
So it is important for us to have someone to review the subject who has no preconceived ideas about diving, and yet is familiar with water sports. Mark is eminent in the World Surf Lifesavers Association, editor of the Oxford Textbook of Sports Medicine in which he wrote the chapter on asthma; clinical director of medicine in a large postgraduate hospital and medical director of the British Olympic Medical Center.
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From Why Asthmatics Should be Allowed to Dive, Mark Harries
It has been agreed that gas can readily escape from the bronchial tree despite the increased intra-luminal secretions or airways narrowing encountered in the asthmatic diver, and so gas trapping should not prove a problem., [page 7]
Conclusions
Asthmatics who dive are at risk from exercise limitation, not peripheral gas trapping. [Page 12]
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From: The Basis for the Pass/Fail Criteria use in Australia and New Zealand, D. F. Gorman (President of the South Pacific Undersea Medical Society)
will asthma or the treatment of asthma predispose the diver to a diving related illness? There is at least a theoretical increased risk of pulmonary barotrauma in asthmatics and some bronchodilators will impair the ability of the lungs to filter venous bubbles. [page 31]
It is possible that weve worried for too long about pulmonary barotrauma in asthmatics and overlooked the far more likely scenario of an asthmatic drowning on the surface. Certainly, local analyses of diving deaths show that asthmatics who die while diving usually do so by drowning on the water surface. [page 32]
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From: The Case for allowing Asthmatics to Dive, Tom S. Neuman
.in a magazine with a circulation of 38,000, there were 104 positive respondents, 22 wheezed daily, 9 dived within 1 hour of wheezing. Those who wheezed within one hour of diving logged 1,241 accident-free dives, and in the remaining asthmatics 12,864 safe dives were logged. [page 40]
Dr Farrell showed in his study that asthmatics have no statistically significant increase in dysbaric illness over the normal population. In his ongoing study of 200 asthmatic divers he also mentioned 30,000 accident-free dives with greater than 20 unscheduled free ascents without incident
[page 40]
In looking over 13 years of collecting mortality statistics and the university of Rhode Island only one death in 1300 could be attributed to asthma. [page 40]
.weve become somewhat more liberal about this because the key seems to be how they function. They either can do the exercise of they cannot do the exercise. The risk for barotrauma doesnt seem to be there. [page 42]
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From: The Case that Asthmatics Should Not Dive, Richard E. Moon
Dr Farrell should be commended for doing for doing a prospective study
, but any such practicable study has the inherent problem that the asthmatics who dive are likely to be self-selected, lower risk individuals. [page 46]
What is the interpretation of these data? It is correct to say that there is no evidence for an increased risk of DCI in asthmatics who dive. However, it is not correct to conclude that there is no risk. To do so it would first be necessary to establish the confidence with which one can exclude such a relationship. [page 48]
There are theoretical reasons why gas trapping could occur in asthmatics and cause pulmonary barotrauma and gas embolism during ascent from a dive. [page 48]
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Thats enough for now, remember that this conference was held in 1995, the diving community seems to be rather slow in disseminating the updated view of asthma and diving.
Ralph
