Diving + Asthma, does it mix?

[DCROOK]

ASTHMA AND DIVING by Fred Bove, MD, PhD
Because of the changes in medical practice, new medications, a better understanding of the spectrum of asthma, and the growing awareness that many divers have some form of asthma and are diving safely, the Undersea and Hyperbaric Medical Society held a workshop on diving with asthma in June of 1995. The proceedings and conclusions of the workshop have now been published, and they provide important new guidelines for managing the individual with asthma who wants to dive.
Several surveys have shown that 4-7% of active divers in the United States have asthma. Data collected by the Divers Alert Network has also shown that diving accidents are mot markedly increased in individuals with asthma. The DAN data on asthma suggested that active asthmatics (someone who is short of breath and actively wheezing) might have a small increase in diving accident risk (either decompression sickness-DCS or arterial gas embolism-AGE), but the increase

Is small and does not reach statistical significance. The only conclusion, which can be drawn from this information, is that there may be a slight increase in risk for a diver who has active asthma.
Both the DAN data and the data from a British sport diving survey failed to show a risk for pulmonary barotrauma in asthmatics. Indeed when reviewing the few cases of asthmatics who died while diving, it was apparent that failure to swim to safety on the surface was a major problem with these individuals.
The new guidelines take into account the need to have normal exercise capacity when diving. The consensus was that lung function must be normal before an asthmatic can undertake diving. If treatment results in normal lung function, the risk of a problem is eliminated, and the individual can dive. The workshop provides information on the measurements needed to determine that lung function is normal.
Obviously the asthmatic that is acutely ill, with difficulty breathing, wheezing, cough, or fever should not dive. The acute illness must be resolved and breathing function restored to normal before considering diving. Full recovery however would allow return to diving, again based on evidence that the breathing test is normal. Individuals who have permanent lung damage from long standing asthma, with chronic emphysema should not dive. It is also important to avoid smoking tobacco if you are asthmatic, as the smoke will sometimes aggravate the asthma.
Source: http://www.scubamed.com/divess.htm

 

[DCROOK]

Should Asthmatics Not Scuba Dive? Lawrence Martin, M.D.

This question is commonly asked in the diving community. Not surprisingly, there is no simple answer. In this chapter I will present background information on the question and offer some general recommendations. The final answer in all cases should rest with an informed patient, the patient's physician and, for open water students, the scuba instructor.

Asthma is probably the most controversial medical condition affecting recreational divers. An estimated 10% to 15% of children have some history of recurrent wheezing, and an estimated 5% to 8% of adults are diagnosed as "asthmatic." Added to these statistics is an estimated several million certified scuba divers, with several hundred thousand newly certified every year, and it is no surprise that many current and would-be divers have some history of asthma.

Asthma is a disease of the airways. Patients prone to asthma can develop intermittent attacks of cough, wheezing, chest tightness, and/or shortness of breath. These symptoms are due to narrowing of the air tubes (bronchi) within the lungs. One major cause of the narrowing is excess mucous in the airways. Because symptoms occur episodically, and often unpredictably, there is no way to know when someone with an asthma history will have an "asthma attack."

Scuba divers breathe compressed air under water, so they must have unobstructed flow of air in order to equalize air pressures. Unequal air pressures are the cause of all barotrauma, including ear and sinus squeeze, and air embolism. Since asthmatics may develop airflow obstruction in the lungs at any time, the question of when, if ever, asthmatics may safely dive is problematic. For reasons, which I will discuss, there are many opinions and no uniform agreement. Quotes in the following table, taken from the medical literature, reflect this difference of opinion. Note that recommendations range from 'never' to 'not with a history of asthma over the previous five years' to 'no diving within two days of wheezing.'

Some recommendations and opinions from the medical literature about asthma and scuba diving.
"A history of bronchial asthma is disquaulifying if there have been any attacks within 2 years, if medication is needed for control, or if bronchospasm has ever been associated with exertion or inhalation of cold air." (Strause 1979)
"Never" - "Once an asthmatic, always an asthmatic" (Linaweaver 1982) "Absolute contraindications: [Astham] attacks within the past 2 yr. Medication is required to prevent or treat episodes of dyspnea. Effort or cold induced asthma." (Hickey 1984)
"Any patient with currently active bronchial asthma should be strictly forbidden to dive. Any patient with a history of childhood asthma, symptoms suggestive of asthma within the past year, suspicion of exercise or cold aire induced asthma should be referred to a pulmonary medicine specialist for evaluation to include challenge testing." (Davis 1986)
"No diving by individuals... who have had clinically significant bronchospasm within the last five years, whether or not they take medications and irrespective of the precipitating event." (Neuman 1987)
"...a conservative recommendation is that any asthmatic with frequent flareups or continuous need for medication to control symptoms, should refrain from diving. Conversely, an adult who has "grown out" of asthma, or has been symptomomatic for some time ...with normal lung function, may participate in recreational diving. In all instances, of course, the potential risks should be explained to the diver." (Maritn 1992)
"Divers using bronchodilators are disqualified. The bronchodilator itself leads to increased risk of arrhythmiaias." (Millington 1988)
"Well-controlled, mild asthmatics should be allowed to dive during remissions, but be particularly advised about the risks of rapid ascent." (Denison 1988)
"All individuals who have current active asthma are advised not to dive. Any individual who seems to have outgrown his asthma and has not had any bronchospasm, wheezing, or chest tightness and has not used any bronchodilator recently may be a candidate for diving if a cmomplete hbatter of PFTs are normal." (Neuman 1990)
"Never" - "Childhood asthma never goes away and continues to be a hazard to divers, even if apparently arrested and asymptomatic in adulthood." (Greer 1990)
"If the person ever has had bronchospasm associated with exercise or inhalation of cold air, diving is contraindicated." (Harrison 1991)
"...not to dive within 48 hours of wheezing is safe [reasonable]." (Farrell 1990)
"in principle, diving is absolutely contraindicated in those with air-trapping pulmonary lesions or bronchial asthma." (Melamud 1992)
Not with: "History of asthma over the last 5 years, use of bronchodilators over the last 5 years, respiratory rhonchi or other abnormalities on auscultation." (edmonds 1991, Edmonds 1992)
"Intending divers with a past history of asthma and asthma symptoms within the previous five years should be advised not to dive." (Jenkins 1993)
"The recommendation that an asthmatic patient not dive should be determined by the history and severity of the desease." (Neuman 1994)

 

[DCROOK]

WHY IS THERE A WIDE RANGE OF OPINION ON ASTHMA AND DIVING?

1. Asthma is a disease with a wide range of frequency and severity of symptoms.
Some authors have recommended that anyone "with asthma" not go scuba diving. However, such a broad prohibition flies in the face of reality, since it includes a large group of people with a history of asthma who, in fact, dive often and without any problem.

On the other hand, any asthmatic who is constantly wheezing and coughing should obviously not scuba dive. So where should the line be drawn between remote history of asthma and active disease? It seems that most experts would draw the line at some arbitrary point, usually denoted by patient symptoms and need for medication (see quotes in table). However, none of the guidelines for deciding who should not dive is established by any studies of which I am aware; they are all "best guess" recommendations. If there is a line to draw somewhere, and I believe there is, it should be based on individual evaluation as opposed to something as arbitrary as "5 years" or "2 days" without symptoms. (In contrast to many earlier recommendations, the importance of an open mind and individual assessment are becoming increasingly recognized; see Neuman, et. al., 1994.)

The worse the asthma, in terms of needs for medication, symptoms, or degree of airflow obstruction, the riskier the diving (at least physicians perceive it this way). There can be no rule about diving that fits all asthmatics, except for the no-brainer that if you never dive you'll never have a diving accident. Ultimately the "line" for diving vs. no diving should be based on a thorough evaluation of the individual, and not on any arbitrary and unproven criteria.
2. Air trapping can lead to fatal air embolism, yet many asthmatics do dive, and without any definite evidence for increased accident rate.
The major theoretical concern is an increased risk of air embolism. This can occur if an area of the lungs traps air under water. In theory, mucous in the airways may allow air to pass by as the diver descends, but then trap the air on ascent. On ascent the trapped air will expand and could rupture the lungs, putting bubbles into the circulation. The result can be a non-fatal or fatal stroke Other theoretical asthma-related problems, all of which may lead to drowning, include:
• The possibility of asthma exacerbation from physical exertion,
inhalation of hypertonic saline (seawater), or from breathing dry,
compressed air (Edmunds 1991);
• Increased work of breathing due to increased air density at depth;
• Increased risk of heart rhythm disturbance in people using a
bronchodilator (the most common type of asthma medication)
(Millington 1988);
• Potential of bronchodilator drug to cause enlargement of blood vessels
in the lungs. These blood vessels normally capture small venous
bubbles and keep them from entering the arterial circulation.
Drug-induced dilation may allow the venous bubbles to enter the arterial
circulation as gas emboli (Edmunds 1992, Jenkins 1993);
• Increased risk to diving companions if the asthmatic gets into trouble.
Despite all these theoretical objections, many asthmatics do
dive, and without mishap. Information in this area is based mainly on surveys
of active divers and retrospective compilation of accident data.

This information appears in bits and pieces in the medical literature, in Divers Alert Network's annual accident reports, and in surveys of diving asthmatics. There is no statistically valid, published study that definitively answers the question “Should Asthmatics Not Scuba Dive?

What follows is a summary of data and information relevant to the question.
A survey of responders to a British dive magazine questionnaire found that: 89 of 104 had asthma since childhood; 70 wheezed less than 12 times a year; and 22 wheezed daily (Farrell 1990). The entire group had cumulatively made 12,864 dives and not suffered any instances of pneumothorax or gas embolism; only one diver reported decompression sickness. Interestingly, 96 of the divers reported using an asthma inhaler just before diving and some were also using preventive medication such as steroids. The authors' conclusion that "the British Sub Aqua Club's recommendation to divers not to dive within 48 hours of wheezing is safe" met with strong disagreement in subsequent letters to the medical journal (Martindale 1990, Watt 1990). In a clarification, the authors of the original paper stated the word "reasonable" should have been substituted for the word "safe," and reaffirmed their recommendation (Glanvill 1990).

Of 10,422 responders to a survey in Skin Diver, 870 (8.3%) answered yes to the question "Have you ever had asthma?” 343 (3.3%) indicated they "currently have asthma"; 276 (2.6%) stated that they dive with asthma ( Bove 1992). Diving accident experience among the asthmatics was not reported.

Of responders to a questionnaire in Alert Diver, DAN's bimonthly magazine published, 88.7% (243 divers) reported taking some medication for asthma, and 55.8% took medication just before a dive (Corson 1992). Of this group, 73 (26.4%) had a history of hospitalization for asthma. 279 individuals reported a total of 56,334 dives. Eleven cases of "decompression illness" (AGE or DCS) were reported in 8 individuals, or one in 5100 dives, "significantly exceeding" the estimated risk for unselected recreational divers by a factor of 4.16. The authors concluded "the risk of decompression illness is higher in the surveyed asthmatics than in an unselected recreational diving population" (Corson 1992).
Source: http://www.mtsinai.org/pulmonary/books/scuba/asthma.htm

 

[rcohn]

Dr mar5tins book is based on pre 1995 data before the conference "Are Asthmatics Fit to Dive."

Should Asthmatics Not Scuba Dive? Lawrence Martin, M.D.

This question is commonly asked in the diving community. Not surprisingly, there is no simple answer. In this chapter I will present background information on the question and offer some general recommendations. The final answer in all cases should rest with an informed patient, the patient's physician and, for open water students, the scuba instructor.

Asthma is probably the most controversial medical condition affecting recreational divers. An estimated 10% to 15% of children have some history of recurrent wheezing, and an estimated 5% to 8% of adults are diagnosed as "asthmatic." Added to these statistics is an estimated several million certified scuba divers, with several hundred thousand newly certified every year, and it is no surprise that many current and would-be divers have some history of asthma.

Asthma is a disease of the airways. Patients prone to asthma can develop intermittent attacks of cough, wheezing, chest tightness, and/or shortness of breath. These symptoms are due to narrowing of the air tubes (bronchi) within the lungs. One major cause of the narrowing is excess mucous in the airways. Because symptoms occur episodically, and often unpredictably, there is no way to know when someone with an asthma history will have an "asthma attack."

Scuba divers breathe compressed air under water, so they must have unobstructed flow of air in order to equalize air pressures. Unequal air pressures are the cause of all barotrauma, including ear and sinus squeeze, and air embolism. Since asthmatics may develop airflow obstruction in the lungs at any time, the question of when, if ever, asthmatics may safely dive is problematic. For reasons, which I will discuss, there are many opinions and no uniform agreement. Quotes in the following table, taken from the medical literature, reflect this difference of opinion. Note that recommendations range from 'never' to 'not with a history of asthma over the previous five years' to 'no diving within two days of wheezing.'

Some recommendations and opinions from the medical literature about asthma and scuba diving.
"A history of bronchial asthma is disquaulifying if there have been any attacks within 2 years, if medication is needed for control, or if bronchospasm has ever been associated with exertion or inhalation of cold air." (Strause 1979)
"Never" - "Once an asthmatic, always an asthmatic" (Linaweaver 1982) "Absolute contraindications: [Astham] attacks within the past 2 yr. Medication is required to prevent or treat episodes of dyspnea. Effort or cold induced asthma." (Hickey 1984)
"Any patient with currently active bronchial asthma should be strictly forbidden to dive. Any patient with a history of childhood asthma, symptoms suggestive of asthma within the past year, suspicion of exercise or cold aire induced asthma should be referred to a pulmonary medicine specialist for evaluation to include challenge testing." (Davis 1986)
"No diving by individuals... who have had clinically significant bronchospasm within the last five years, whether or not they take medications and irrespective of the precipitating event." (Neuman 1987)
"...a conservative recommendation is that any asthmatic with frequent flareups or continuous need for medication to control symptoms, should refrain from diving. Conversely, an adult who has "grown out" of asthma, or has been symptomomatic for some time ...with normal lung function, may participate in recreational diving. In all instances, of course, the potential risks should be explained to the diver." (Maritn 1992)
"Divers using bronchodilators are disqualified. The bronchodilator itself leads to increased risk of arrhythmiaias." (Millington 1988)
"Well-controlled, mild asthmatics should be allowed to dive during remissions, but be particularly advised about the risks of rapid ascent." (Denison 1988)
"All individuals who have current active asthma are advised not to dive. Any individual who seems to have outgrown his asthma and has not had any bronchospasm, wheezing, or chest tightness and has not used any bronchodilator recently may be a candidate for diving if a cmomplete hbatter of PFTs are normal." (Neuman 1990)
"Never" - "Childhood asthma never goes away and continues to be a hazard to divers, even if apparently arrested and asymptomatic in adulthood." (Greer 1990)
"If the person ever has had bronchospasm associated with exercise or inhalation of cold air, diving is contraindicated." (Harrison 1991)
"...not to dive within 48 hours of wheezing is safe [reasonable]." (Farrell 1990)
"in principle, diving is absolutely contraindicated in those with air-trapping pulmonary lesions or bronchial asthma." (Melamud 1992)
Not with: "History of asthma over the last 5 years, use of bronchodilators over the last 5 years, respiratory rhonchi or other abnormalities on auscultation." (edmonds 1991, Edmonds 1992)
"Intending divers with a past history of asthma and asthma symptoms within the previous five years should be advised not to dive." (Jenkins 1993)
"The recommendation that an asthmatic patient not dive should be determined by the history and severity of the desease." (Neuman 1994)

 

[rcohn]

Hi rchon,

I am not quite sure why you launched this public attack. I don't ever remember saying I was an expert in this field. I did say that I am trying to choose a topic for a thesis, and as this interests me, it had potential. The last post that I made was in juxtaposition with a pharmaceutical global research company, with the home office in Toronto.

Please don't take my findings as strict medical advice, only research, as I pointed out early in the thread. As such, I will not respond to any of your questions, as they are medical in nature. Your questions are interesting, and I'm sure they are factual, but the problem is they can be open to debate depending on which expert you talk to.

One thing I have found interesting though, you mentioned that 3% - 8% of the diving population has asthma. I am sure many people with asthma have been told as children that they "cannot dive" because of there disability. This would give them the urge to dive just to prove that comment wrong (human nature). In many cases, this would not be reported to instructors or dive shops. I would imagine the population that dives is most likely a lot higher then 8%, probably somewhere more around 15 - 25% (just a guess).

As I acquire more information, I will post my research. Some of it might contradict my previous posts.

You were publicly attacked because you presented yourself as an expert (no references, quotes, or data; just your expert opinion) while you clearly have no expertise whatsoever. The information you were so kind to provide was out of date and contradicted the latest current medical thinking. If you have read the various posts you have recently added, you would find most (particularly the more recent ones published after 1995) contradict your original assertions. Hopefully you have learned something from the exercise.



Ralph

 

[rcohn]

Let's add this info to this thread.

From: http://www.ymcascuba.org/ymcascub/asthmatc.html

Dr. Duke Scott, Medical Adviser

The YMCA of the USA has been and continues to be dedicated to meeting the needs of all people, including those with disabilities, providing them with the opportunity to reach their fullest potential and enhancing the quality of their lives. In accordance with this philosophy, the YMCA scuba Program has been proud to assume the leadership role in dealing with disability issues as they apply to the diving community. YSCUBA has already developed successful programs for physically challenged and diabetic divers. After several years of study, research, and appropriate consultation, YSCUBA is now prepared to initiate a program which will allow qualified asthmatics to participate in YSCUBA training.

Asthma affects more than 14 million Americans. At least 75 percent of asthmatics demonstrate hypersensitivity to airborne allergens. Atopy, the genetic predisposition for the development of IgE antibodies to common allergens, is an accepted risk factor for asthma among children and adults. In addition to allergens, numerous activities, or exposures that precipitate or exacerbate episodes of asthma, have been identified. These "triggers" include viral infections, environmental pollutants, medications, foods, sustained exercise, cold, and emotional distress. Identification and avoidance of these allergens and triggers are important components of asthma management. They obviously are important in determining which asthmatics can safely participate in scuba training and scuba diving.

During the 1990's impressive strides were made in the management of asthmatic individuals. The reason for this is two-fold. First, there was the realization that asthma is a chronic inflammatory disease involving the lungs' bronchial tree. This changed the focus of treatment from symptomatic therapy to preventive therapy by utilizing medications that inhibit or reduce bronchial inflammation. Second, a multitude of anti-inflammatory drugs have been developed. These new drugs offer a prolonged period of action and therefore increased protection during periods of increased exertion, such as during scuba. These two factors have revolutionized the treatment of mild to moderate asthmatics. This allows us to approach asthmatics based on their level of function as opposed to their classification. That is, their ability to exercise is independent of whether or not their asthmatic condition requires medication for control.

In the third edition of Diving Medicine (1997), Dr. Tom S. Neuman discusses the case for and against asthmatic scuba divers. I found his case for allowing selective asthmatics to participate in scuba programs very compelling. I recommend that any of our YMCA instructors who contemplate teaching asthmatics to dive become familiar with his recommendations.

Dr. Neumann first discusses the studies and concepts that are most frequently used to argue against diving for asthmatics. He then explores these studies, showing how some of the results may have been misinterpreted. In fact, new studies are described that contradict some of the previous findings. Lastly, he reports on two recent symposia, attended by diving-medicine experts, which concluded that "asthma did not predispose to diving-related pulmonary barotrauma" and that "the limiting factor for asthmatics is adequate ventilatory capacity underwater."

In light of their conclusions, Dr. Neumann suggests that the research data to this point does not support the absolute banning of all asthmatics as diving candidates. Also, the diving community cannot ignore the excellent safety record of the many "closet" asthmatic divers in the United States and certified asthmatic divers of the British Sub-Aqua Club. The B.S.A.C. does not certify exercise-induced asthmatics. On the other hand, we cannot ignore the data that suggests the potential risk of barotrauma is greater in asthmatics. Still, it is obvious that asthmatics are a very heterogeneous group with varying degrees of respiratory difficulties. Therefore, as with diabetics, each asthmatic's eligibility for scuba training should be evaluated on his or her own merits.

Based on these findings, the YSCUBA Program recommends the following guidelines for determining which asthmatics are fit to participate in our scuba training programs. This protocol should be used by a potential asthmatic scuba student in consultation with his or her physician to determine eligibility for scuba training. Once accepted, the student must be closely monitored by the instructor. If the student's asthma becomes symptomatic during pool training or open-water dives, he or she must be dropped from the class and disqualified from further scuba training.

The YSCUBA Program began accepting qualified asthmatics as scuba students as of January 1, 2000. Initially, all potential asthmatic scuba students are required to receive clearance by the YSCUBA Medical Advisor prior to being accepted into an instructor's class. The reason for this is twofold. The first is to be sure that the student and YSCUBA are covered by our professional liability insurance. Our insurance will only cover us if the asthmatic meets the requirements set forth in the Protocol. Second, the YSCUBA training of asthmatics will be closely scrutinized by the other diving agencies as a whole. Therefore, we must monitor the progress of these individuals closely, not only during their training, but also during their entire diving experience. The data we accumulate will be utilized to confirm our position that select asthmatics are fit to dive. It will also be used to modify the Protocol as needed and to aid us in developing more effective teaching methods. Every instructor who chooses to teach asthmatics will be required to submit data concerning the students' response to scuba training. Every asthmatic student will be requested to periodically submit information concerning his or her diving activities. The necessary forms and method for reporting this information will be provided by the YSCUBA Medical Advisor. The YSCUBA instructor and/or the asthmatic student's physician should contact the YSCUBA Medical Advisor, Dr. Duke Scott to obtain a copy of the Asthmatic Protocol.

Duke Scott, M.D.
YSCUBA Medical Advisor

 

[DCROOK]

No, I never said I am an expert. I'm just trying to find the all the facts. Of course my original statements contradict my earlier ones. What interests me is how the leaders in this field differ in opinion. They are not my opinions. Whenever possible, I will state references, as I have been able to do with all posts but one. Thank you for adding something useful to this thread. I have refrained from commenting on any medical opinion. You seem to do this with vigor, however. What might your background be regarding this topic?

You were publicly attacked because you presented yourself as an expert (no references, quotes, or data; just your expert opinion) while you clearly have no expertise whatsoever. The information you were so kind to provide was out of date and contradicted the latest current medical thinking. If you have read the various posts you have recently added, you would find most (particularly the more recent ones published after 1995) contradict your original assertions. Hopefully you have learned something from the exercise.



Ralph

 

[rcohn]

Let's add this info to this thread.

From: http://www.ymcascuba.org/ymcascub/asthmatc.html

Dr. Duke Scott, Medical Adviser

Based on these findings, the YSCUBA Program recommends the following guidelines for determining which asthmatics are fit to participate in our scuba training programs. This protocol should be used by a potential asthmatic scuba student in consultation with his or her physician to determine eligibility for scuba training. Once accepted, the student must be closely monitored by the instructor. If the student's asthma becomes symptomatic during pool training or open-water dives, he or she must be dropped from the class and disqualified from further scuba training.

The YSCUBA Program began accepting qualified asthmatics as scuba students as of January 1, 2000. Initially, all potential asthmatic scuba students are required to receive clearance by the YSCUBA Medical Advisor prior to being accepted into an instructor's class. The reason for this is twofold. The first is to be sure that the student and YSCUBA are covered by our professional liability insurance. Our insurance will only cover us if the asthmatic meets the requirements set forth in the Protocol. Second, the YSCUBA training of asthmatics will be closely scrutinized by the other diving agencies as a whole. Therefore, we must monitor the progress of these individuals closely, not only during their training, but also during their entire diving experience. The data we accumulate will be utilized to confirm our position that select asthmatics are fit to dive. It will also be used to modify the Protocol as needed and to aid us in developing more effective teaching methods. Every instructor who chooses to teach asthmatics will be required to submit data concerning the students' response to scuba training. Every asthmatic student will be requested to periodically submit information concerning his or her diving activities. The necessary forms and method for reporting this information will be provided by the YSCUBA Medical Advisor. The YSCUBA instructor and/or the asthmatic student's physician should contact the YSCUBA Medical Advisor, Dr. Duke Scott to obtain a copy of the Asthmatic Protocol.

Duke Scott, M.D.
YSCUBA Medical Advisor

I noted that the YMCA has decided to remove the actual protocols from the website. However, a search was able to find two sites that still have them posted.

The first claims to present the YMCA protocol (I can't verify that it is accurate)
http://my.voyager.net/~rhodgson/Asthma.htm

The second site has the SSI protocol, which is either identical, or extremely close, to the YMCA's.
http://www.scubasciences.com/pdf%20files/Medical%20Stuff/ssi-asthmatic%20information.pdf

Ralph