Asthma and diving

[PVADiving]

Asthmatics can experience something called "air trapping" in their lungs, even when not having an asthma attack. Air is trapped in one of the small sacs in the lung and cannot escape. When the diver ascends the air expands....and you can predict the rest. Before you dive with asthma you should see a pulmonary doctor (preferably one who is familiar with scuba) and be cleared to dive by them. Contact DAN to find one. Having said all that there are asthmatics who can dive safely.

 

[CuriousMe]

I found it in this thread post #10. I'll quote him below and highlight what led me to that statement as a general summary of what the rest of the asthma threads contain. I checked my link in the first post and it isn't working now so it may have been hard to find what I was talking about. If you have any other questions please feel free to ask, I was simply summarizing what I found while using the search function.
Ber

It's true that you if you have Asthma, you have it whether you're in the midst of an attack or not. I've heard folks describe it as twitchy airways....they're much more prone to react than most folks' airways. The way they react is that they swell up, produce more mucous and constrict.

There are some things you can do to know your lungs and manage your condition though. One of the things I do is I take my Peak Flow and FEV1 with a little handheld spirometer (cost about $30 US). I measure it every morning and night. This way I can see if my lung function is being effected by anything. (when diving I also take it shortly before getting on the boat). My lungs tend to be slow to react to something....it can be 5 or 6 hours before I see a real reaction to a trigger.

So, while it's true that if you have Asthma, you have asthma whether you're in the midst of an attack or not.....it doesn't mean that your lung function is always affected. (personally, my lung function when my asthma is controlled is generally in the 115% - 120% of the predicted for my age, gender, height, etc).

Of course...as everyone else has said....the first thing you want to do is talk to a diving doc (preferably a Pulmonologist).

Peace,
Cathie

 

[rcohn]

I did some searching on the web and found these interesting articles. I may dig up some more later.



Ralph


From: http://www.chestjournal.org/cgi/reprint/112/3/575.pdf

Pulmonary Barotrauma in Divers

Can Prospective Pulmonary Function

Testing Identify Those at Risk?



Alfred A. Bove, MD, Ph.D.



The paper by Tetzloff and colleagues in this issue

of CHEST (see page 654) provides important clinical

observations that support a role for prospective

pulmonary function testing as a means of distinguishing

individuals with a history of reactive airway

disease who can dive safely from those who might be

at risk for pulmonary barotrauma. Although their

study is retrospective, they were able to identify

changes in the flow-volume curve; specifically, reduced

mid-expiratory flow at 25% of vital capacity

occurred in pulmonary barotrauma patients compared

with those who had decompression sickness,

but not pulmonary barotrauma. FEV1 was similar in

both groups.

.

As understanding of reactive airway disease improves,

and the relationship between exercise, reactive

airway disease, and functional testing is clarified,

a more precise screening capacity will be available

for the practicing physician. The fact that Tetzloff

and colleagues were able to identify risk factors in

93% of the patients who suffered pulmonary barotrauma

after diving indicates that we can develop the

necessary screening to eliminate individuals who are

at risk.



As usual, a careful history is important. Identifying

lung cysts or blebs on CT and reduction of the MEF

25 flow to below 80% of normal may contribute to

the screening of high-risk individuals. Larger studies

are needed to confirm this combination of screening

techniques, and attention must be paid to the cost of

screening, particularly if screening involves CT studies.

However, if flow-volume curves can identify

high-risk individuals who have a history of asthma

and wish to dive, the cost of pulmonary screening is

an excellent investment.

From: http://www.jastra.com.pl/nurek/asthma.htm

Asthmatic amateur divers in the United Kingdom,
Dr. P. J. Farrell

Results

Out of twenty five BSAC medical referees questioned, nineteen replied. They recorded 813 active divers of which 31 were asthmatics giving a prevalence of 3.96%. The chambers reported 402 cases of treated dysbaric illness in the period 1989 to 1993 of which 9 were asthmatics. Statistically chi-squared with Yates correction was 3.607 (P > 0.5) i.e. asthmatics showed no increase in dysbaric illness over the general population.

Discussion

The 4% prevalence of asthmatics in the U.K. scuba-diving population is interestingly similar to Bove et al. [1] where 2.6% of his sample dived despite being asthmatic, in a country where asthma is considered to be an absolute contra-indication to diving. I included all cases of decompression illness and air embolism as one illness as many people believe that they cannot be separated clinically in most cases. Only one of the chambers contacted failed to record if a patient was asthmatic and so their data are not included. However all the hospital case notes were reviewed and asthma was not mentioned in a single medical history.

In the U.K. the National Sport Diving Medical Committee (representing the BSAC, the Sub-Aqua Association and the Scottish Sub-Aqua Club) are happy with the existing guidelines in allowing carefully selected asthmatics to dive, as there is no evidence that asthmatics are more at risk of decompression illness than the rest of the U.K. diving population.

Interestingly, Corson et al. [2] in their survey from "Alert Diver" found 279 asthmatics of whom 26.4% had been hospitalized for asthma; of these 5.8% had been hospitalised 6 times or more and they had a highly significant increased risk of decompression illness.

The authors commented that the risk needs quantifying according to the severity of the asthma. It is suspected that in the U.K. many of the divers in this group would have been advised not to dive. The U.K. policy of enabling some asthmatics to dive has allowed the exclusion of the more severe cases of asthma. The asthmatics who are allowed to dive have been educated as to the safest way of diving.

Interestingly, a recent paper by Neuman et al. [3] has come to much the same conclusions concerning the fitness of asthmatics to dive. The medical ban on asthmatics diving has not prevented them diving in the rest of the world, where an unselected and uneducated group have been shown to be at increased risk of suffering from decompression illness.

 

[rcohn]

One more.

From : http://www.wemjournal.org/wmsonline...&issn=1080-6032&volume=013&issue=03&page=0187

Objective.

—In Australia, a medical examination is required before undertaking a scuba diving course in order to screen for contraindications to diving. No further medical screening is required, and yet divers may develop diseases during their diving careers. This study aimed to survey experienced recreational scuba divers to determine the prevalence of diseases contraindicated in diving.

Methods.—A cross-sectional, postal survey was taken of divers belonging to scuba diving clubs across Australia.

Results.—Three hundred forty-six divers returned completed questionnaires. Two hundred fifty-four (73.4%) were male, and 258 (74.6%) were aged 31 to 60 years. The mean years of diving equaled 10.6 ± 9.18 years, and the mean number of dives undertaken was 414 ± 740 dives. One hundred sixty-two (46.8%) divers were overweight, 45 (13.0%) divers required regular medication, and 39 (11.3%) divers smoked. Thirty-six (10.4%) divers reported a past or present history of asthma, and the same number reported hypertension or coronary heart disease. Eighty-six (24.9%) divers reported past or present psychological symptoms. Forty-two (12.1%) divers reported hearing difficulties, and 81 (23.4%) divers reported past or present tinnitus. Two divers had a past history of epilepsy, 2 had a history of pneumothorax, and 1 was diabetic.

Conclusions.—Experienced, recreational scuba divers continue to dive despite medical contraindications. This raises the questions: Did the divers fail to disclose these conditions at the initial examination, or did these conditions develop subsequently? Is the risk associated with these conditions clinically significant, and should screening examinations be undertaken at regular intervals? The high prevalence of hearing difficulties and tinnitus may be the result of aural barotrauma and requires further research.

Few other studies have examined the prevalence of chronic disease among scuba divers. A recent Australian study by Cresp et al

6 examined the health status of recently qualified divers. As expected, the subjects in that study had a similar sex ratio (72% male), were younger (median age, 24 years), leaner (24.0% overweight or greater), and inexperienced (76% had done fewer than 20 dives). Compared with the present study, Cresp et al6 found a greater prevalence of asthma and obstructive airways disease (10.3%) and hypertension (4.2%) but a similar prevalence of epilepsy (1.0%), diabetes (0.2%), ischemic heart disease (0.2%), and smoking (11.6%). The authors noted that a number of divers commented on how easy it was to avoid the detection of medical conditions during the diving medical examination. Hansen et al10 reported a higher prevalence of hypertension (9.7%) and active asthma (4.2%) in their large study of experienced divers in the United States

The above discussion is based on the premise that the theoretical risks of diving with medical contraindications are clinically significant. This may not be the case. Indeed, some studies have challenged traditional theory by suggesting that the risk associated with some conditions, including asthma and diabetes, may not be as great as originally thought.

8,13,15,16 Furthermore, the available evidence shows that diving fatalities as a direct result of medical conditions are rare. An analysis of the deaths of 286 fatalities in the United Kingdom and the United States between 1990 and 1994 showed that health factors, as possible contributory causes, accounted for 2% and 5.1% of deaths, respectively.16 Australian figures appear to be higher. Of the 46 scuba diving deaths in Australia between 1993 and 1997 inclusively, 8 (17.4%) were thought to have a possible medical contributing factor. Presumed cardiac events were considered the most common contributing medical conditions. These diving deaths included 2 cases of planned suicide.17–21

 

[rcohn]

From: http://www.chestjournal.org/cgi/reprint/112/3/575.pdf

Note the paper Bove cites, it presents evidence that it is not the asthma, but rather the additional lung conditions that some asthmatics develop, which seems to be linked to barotrauma. Pulmonary function testing can identify these conditions.



I hope that one of the physicians can supply more details on this.



Ralph

 

[Ber Rabbit]

IMO it is time to stop scaring asthmatic divers with unsubstantiated theories that are supported neither by the medical experts nor by the fatality statistics.

Ralph

I did want to make sure you saw my second generalization that stated that some asthmatics can be certified to dive. I'm always interested in the latest information and studies related to diving and you have provided some good information. It would be most kind of you to allow learning to occur instead of lambasting someone for using the information they have been able to find to date. I research medical issues each time I teach a class to see what the latest studies say but I must also follow the standards set by my agency (NAUI) and that has some bearing on how I approach these issues. Last year they changed the absolute contraindications from asthma to active asthma but never gave us any evaluation criteria such as those the YMCA uses in their program. When I get a potential student with asthma I refer them to a YMCA instructor so they can learn to dive in a program designed to monitor asthmatics. Until I get more information from my organization that's the best I can do.

I wish nothing but safe diving to all.
Ber

 

[cyklon_300]

My symptoms have ranged from the extreme to non-existent. As a child, I had many episodes that required visits to the ER. I did not have a medical release to participate in PE until the 7th grade. By my early 30s, my symptoms had subsided to the point where I was able to be a competitive triathlete.

In my late 30s the asthma returned with renewed intensity but now, with allergy injections and improved oral medications, I am essentially symptom-free again.

There is a wealth of misinformation surrounding this condition in the dive community...I've had people tell me I have a death-wish for diving with it, that they would never have me as a buddy because I might have an 'attack' and leave them with an emergency to contend with, that asthmatics are more prone to 'panic' that non-asthmatics, and that all asthmatic divers have poor air consumption rates.

In 25 yrs of diving I have never had ANY situation underwater that was related to my respiratory condition. IMO most of the hysteria is generated by liability concerns, not medical facts.

 

[Ber Rabbit]

IMO most of the hysteria is generated by liability concerns, not medical facts.

You have a good point there. In today's litigious society it's usually better to be overly cautious than to lose everything you have.
Ber

 

[cyklon_300]

was issued by an allergist who is asthmatic and a diver.

 

[mmcdds]

I've only been diving for a couple of years, but have been a diagnosed asthmatic for about 30 years. My symptoms are typically mild, so mild in fact that I seldom am required to take any medication. That being said, I have never had any problems diving that were in any way associated with my asthma. Just having asthma shouldn't automatically exclude anyone from diving, if its well controlled and your MD ok's it then I see no reason not to dive, although if I were having a bad day (and every asthmatic knows what a bad day feels like) I wouldn't get in the water. Common sense should always prevail.