Asthma & Scuba Diving
Should Asthmatics Not Scuba Dive?
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 are 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 sucba diving. "A history of
bronchial asthma is disqualifying 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: [Asthma] 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 air 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 flare-ups 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 complete hatter 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 bronchi 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
disease." (Neuman 1994)
WHY IS THERE A WIDE RANGE OF OPINION ON ASTHMA
AND DIVING?
There are three basic explanations, which are summarized below
and then discussed at length in the following pages.
Asthma is a condition with a wide range of both the frequency
and severity of symptoms such as wheeze and chest congestion;
when used without precise definition or description, the term
"asthma" may mean different things to different people. Despite
sound theoretical objections as to why asthmatics should not
dive, there is no solid evidence that scuba-diving asthmatics
have an in-creased accident rate. There are differences in
philosophy among physicians and scuba professionals about
personal risk-taking.
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.)
To demonstrate variability of the label "asthma," I have made
up 10 different scenarios for a hypothetical 30-year-old man
with some history of asthma.
Each scenario is ranked for severity of the asthma, from 1
(least) to 10 (most). In each case the subject might
legitimately check "yes" to a scuba diving questionnaire asking
if he ever had asthma. If the questionnaire is for a certification
course, a "yes" answer in each case would result in the
requirement that the applicant obtain "medical clearance."
The consensus among dive medicine physicians would probably
be to say "yes" to scenarios 1-3 (he may dive), and a clear "no"
to scenarios 8-10 (he may not dive). Nos. 4-7 are problematic;
most likely the percentage of diving physicians saying "no"
would increase as we go from number 4 to 7. The point is that
there is asthma and there is asthma. The worse the asthma, in
terms of need 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);
10 SCENARIOS FOR A 30-YEAR-OLD MAN WITH A
"HISTORY OF ASTHMA," RANKED FROM LEAST (1) TO
MOST SEVERE (10)
1. Had asthma as child, grew out of it at age 12, no symptoms
or trouble since. No symptoms when exercising.
2. Had asthma as child. No problems at all except very, with
heavy exertion, such as running cold weather, patient has noted
a slight cough and shortness of breath. the last time was about
five years ago. Symptoms always went away without treatment.
3. No asthma as child. Seven years ago patient had to use an
asthma inhaler. Occasionally feels "chest congestion" with a
cold, but it always abates without any specific treatment. Last
asthma treatment was seven years ago.
4. No asthma as a child. About once a year, with a cold, patient
has a little wheezing. Uses an asthma inhaler for a day at most,
and always gets better. Exercises regularly with no difficulty.
5. No asthma as a child. About once a year gets a mild attach,
and takes medication for a few days, including both pills and an
inhaler. Between attacks feels well.
6. Had asthma as a child. Grew out of it at age 10, then at age
25 asthma recurred. Now carries an asthma inhaler and uses it
about once a month, at most. In the past five years has had bad
asthma attacks, requiring steroid medication.
7. No asthma until age 22. Now uses an asthma inhaler
regularly, but feels well controlled except for occasional
exacerbations. Lung function is normal when tested between
attacks.
8. Uses prednisone tablets and an inhaler to control asthma
symptoms. Doctor adjusts prednisone dose, sometimes to as
low as only 5 mg a day, other times as high as 40 mg a day.
Lung function is near normal when tested between attacks.
9. Has been hospitalized about once a year for past five years for
a severe asthma attack. Has breathing machine (nebulizer) at
home for inhalation of bronchodilator, which he requires
regularly. Lung function shows modest impairment when tested
between attacks.
10. Hospitalized several times a year for asthma. Lung function
always abnormal when tested.
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 (see box). There is no
statistically valid, published study that definitively answers the
question heading this chapter (and there may never be). 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. A total of 56,334 dives
were reported by 279 individuals. 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 that "the risk of decompression
illness is higher in the surveyed asthmatics than in an
unselected recreational diving population" (Corson 1992).
Data Related to Asthma and Diving
Surveys of Diving Asthmatics
British survey (Farrel 1990) Survey of Skin Diver readers (Bove
1992) DAN survey of Alert Diver readers (Corson 1992)
Reviews of Accident/Mortality Statistics
DAN retrospective review (Corson 1991) DAN 1994 Accident
Report (DAN 1994) University of Rhode Island Accident
Statistics (McAniff 1991) Review of Accidents from early 1980s
(Neuman 1987) L.A. County Coroner's Cases, 1985-1990
(Schanker 1991) Australia/New Zealand Experience (Edmunds,
1991, 1992)
Admittedly, there are problems with reader surveys.
Surveys presumably include only asthmatics who continue to
dive and maintain enough interest to read scuba periodicals; as
a result, they may under-represent asthma-related problems
because they don't count asthmatics who quit diving (Watt
1990). However, it is also true that many current asthmatics
choose not to admit that they scuba dive (Lin 1987), so by not
counting all scuba-diving asthmatics the surveys may
over-represent asthma-related problems. The survey data don't
permit comparison of scuba diving asthmatics with and without
accidents as to severity of asthma, level of control with
medication, and reason for any pre-dive medication
(prevention vs. treatment of symptoms). The surveys don't
reveal the character of the dives, e.g., the depths achieved,
episodes of rapid or uncontrolled ascent, and the water
conditions. A retrospective review to assess the risk of asthma
for arterial gas embolism (AGE) and type II decompression
sickness (neurologic impairment from nitrogen bubbles) was
made by DAN for the four years 1987-1990 (Corson 1991).
Fifty-four out of 1213 divers reported to DAN with AGE or
type II DCS had a history of asthma, of which 25 were currently
asthmatic (defined as having an asthma attack within one year
or taking bronchodilator therapy). For a control population,
1000 questionnaires were sent to a randomly selected group of
DAN members, of which 696 were returned; 37 control divers
admitted a history of asthma, of which 13 were currently
asthmatic. There was no statistically significant increase in risk
for type II DCS in the asthmatics. The data for AGE suggested
an approximately two-fold increase in risk for asthmatics, but
did not reach statistical significance (Corson 1991).
The 1994 DAN Accident Report confirmed 465 cases of
decompression illness (including DCS and AGE) among North
American divers during 1992 (DAN 1994). Of this group, there
was a history of current asthma in eight and past asthma in 20,
representing 1.7% and 4.3% of the total, respectively. Except for
the comment that "two individuals were using over-the counter
inhalers for asthma," no information is provided about disease
severity or the role of asthma in any specific accident (DAN
1994).
Scuba diving deaths linked to asthma are infrequent. In the
1970s and 1980s the University of Rhode Island's National
Underwater Accident Data Center kept dive fatality statistics on
U.S. divers. Asthma was not noted as a cause of death in any of
the 1183 autopsies recorded during this period (McAniff 1991).
A review of scuba death reports from the early 1980s found
that, whenever asthma was mentioned, there was either no
explanation of the circumstances, or another, and preventable,
cause of death was present, such as out-of-air-at-depth or
uncontrolled ascent (Neuman 1987).
A review of 18 consecutive scuba diving fatalities at the Los
Angeles Coroner's office between 1985 and 1990 found
"apparent air embolism or lung barotrauma" in four patients; in
none was death linked to asthma (Schanker 1991).
One autopsy report has been published of an asthmatic who
died from scuba diving. She was an obese, 40-year-old diver
with a history of: asthma for four years; an emergency room
visit for asthma three months before her demise; using an
asthma inhaler eight times a day; breathing difficulties on the
day of her dive. The autopsy confirmed arterial gas embolism
and asthmatic bronchitis (Marraccini 1986). (It is noteworthy
that the deceased had denied respiratory problems on her
written dive school application.)
DAN also keeps data on all recreational scuba diving deaths
among North American residents. Ninety-six recreational
scuba diving fatalities were reported for 1992 (DAN 1994).
DAN's analysis found that "Cardiovascular disease is a
prominent immediate cause of death...diabetes mellitus and
bronchial asthma do not appear prominently in this series."
In contrast to the U.S. and British experience, asthma was found
to be a contributing factor in 8% of 124 scuba diving deaths in
Australia and New Zealand (Edmunds 1991, Edmunds 1992).
Most of these deaths were in clinically mild asthmatics who
were otherwise physically fit young men. In a number of cases
the diver was returning to obtain a bronchodilator spray; in
others, medication had been used immediately before the dive.
Edmonds has provided several case histories of asthmatics who
have died during or just after a scuba dive (Edmunds 1991,
Edmunds 1992).
I cannot explain the difference in mortality data between
Australia/New Zealand and the rest of the world. Certainly in
England and the U.S. there appears to be no conclusive evidence
for an increased accident or mortality rate among asthmatics
who dive. This does not mean that diving can be considered
"safe" for asthmatics; it would be a foolish reader who
interprets the data this way. It only means that available
information does not confirm a statistically significant
increase in accidents among divers who admit to having
asthma. As with diabetes, it is quite possible that asthmatics
who would get into trouble scuba diving (for all the theoretical
reasons listed) have 'selected' themselves out of the activity,
for one reason or another.
3. Differing opinions may be based on differences in personal
philosophy. This is the third explanation for varying opinion
about asthma and scuba diving. I mentioned this reason in
discussing the 10 asthma scenarios; for scenarios in the middle
group (4-7), the difference between saying "yes" and "no" to
scuba diving may be attributable to philosophical differences
over "taking risks."
Recreational scuba diving is an inherently risky activity for
anyone; physicians believe that any condition characterized as
"asthma" might well add some extra measure to the sport's
inherent risk. But how much extra risk? No one knows, of
course. Surely the answer must largely depend on the vagaries
of a particular diver's asthma. But even if some precise
measurement of extra risk were known, there is no agreement
over what would constitute unacceptable additional risk for
scuba diving.
For example, according to DAN, in the last 10 years an average
of 85 Americans have died each year while engaging in
recreational scuba diving (DAN 1995). There are a variety of
explanations for these deaths, including diver error and
stupidity, but overall the figure is an accepted fact of
recreational diving; no one seeks to ban the sport because of
these deaths, only to make it safer for all participants. Now, if
one out of these approximately 85 scuba diving deaths per year
could be blamed on asthma, would that be sufficient to ban all
asthmatics from diving? Two? Three?
Similarly, there are an estimated 800 non-fatal accidents a year
reported to DAN, of which about half are confirmed as DCS or
AGE. Again, this is an accepted aspect of the sport and no one
seeks to squelch recreational scuba diving because of its
inevitable accident rate. When it comes to asthma, however,
statistics are examined for some justification to recommend
that asthmatics as a group not dive. But how many accidents
attributable to asthma would trigger this recommendation?
Fifteen? Ten? Five?
I doubt there would be any consensus in answering these
questions. Instead, there would likely be more questions about
the statistics. For example, some might want to know: 'Why
did these divers get into trouble, and not all the other
asthmatics who also dive? Was their asthma worse? Their dive
profiles more extreme? Was there some pattern of behavior that
could be identified and perhaps changed?'
Interpretation of statistics can be subjective, so even as more
studies accumulate the issue will likely remain unsettled and
argued. At the 1995 meeting of the Undersea and Hyperbaric
Medical Society, two eminent dive medicine physicians took
opposite sides of the debate, "Should asthmatics not dive?" Both
physicians know all the literature, and have had experience
treating dive accident victims. With similar knowledge and
backgrounds the two physicians eloquently argued two
different ways. (There was no "winner" but the emerging
consensus from the 1995 UHMS meeting seems to be a more
liberal attitude, as expressed in the 1994 article by Drs. Neuman
and Bove.)
Future debates might focus on the methodology of the studies
or the validity of the statistics, but the real argument is likely
to be over something more subtle: philosophical differences in
personal risk taking. Simply put, any given study on the subject
may be interpreted in different ways, depending on inherent
biases. As a result, for people with mild and non-limiting
asthma, the answer to the question "Should asthmatics not
dive?" will largely depend on who you ask.
WHAT ARE SPECIFIC RECOMMENDATIONS?
My recommendations are presented here for the recreational
scuba diver and would-be diver. These recommendations, based
on both the theoretical risk of AGE and the information at
hand, are not to be construed as specific for any given
individual.
"ACTIVE" ASTHMA.
If the asthma is "active" requiring daily or frequent medication
to control symptoms I would advise against diving altogether.
This is particularly true for any prednisone-dependent
asthmatic. Prednisone is a corticosteroid in pill form, widely
used to treat asthma symptoms. Prednisone-dependent asthma
suggests a severe degree of impairment, and would probably
disqualify for diving.
On the other hand, an asthmatic who is well-controlled on an
inhaled steroid (three types: beclomethasone, flunisolide,
triamcinolone) is likely using the drug not to treat symptoms
but to prevent them, and may be able to dive safely.
I would also classify as "active" any asthmatic with a
demonstrably abnormal test of vital capacity (standard
pulmonary function test, called spirometry), physical
examination (wheezing) or chest x-ray. "Demonstrably
abnormal" means there is no doubt as to the abnormality. This
is an important qualification because sometimes changes are
noted on tests which don't really reflect any significant
abnormality, but instead only a normal variation. If there is
any doubt or question about an abnormality, the patient
should be referred to a diving medicine specialist.
For anyone classified as having "active asthma" the theoretical
risks seem too great for what amounts to a purely recreational
activity. Although some asthmatics do use a bronchodilator
inhaler just before a dive (Farrell 1990, Lin 1987, Corson 1992)
this practice is certainly not recommended by physicians. Thus
there is an admitted paradox: "active" asthmatics do engage in a
theoretically risky recreational activity without apparent
mishap, but physicians> (myself included) are not willing to
condone it. Nor are we willing to provide sanction for "active"
asthmatics to begin scuba diving as a new activity.
At some point it must be acknowledged that diving is different
from swimming or jogging; any asthma exacerbation under
water could lead to panic and drowning. I would advise people
in this group to go snorkeling instead, or take up some other
water sport such as swimming, sailing or windsurfing.
"CHILDHOOD-ONLY" ASTHMA.
If someone had childhood asthma, and as an adult has had no
asthma symptoms or required asthma medication, and is
otherwise in good physical condition, there should be no
medical restriction to scuba diving. I would not require an
examination for people in this group, but if one is done it
should reveal no wheezing. A breathing test and chest x-ray, if
done, should be normal. While this recommendation for
childhood-only asthma appears to reflect a consensus among
diving-trained physicians it should be pointed out that some
experts feel even remote asthma poses an unacceptable risk for
diving-related barotrauma (Linaweaver 1982, Greer 1990).
"INACTIVE" ASTHMA.
The person in between the "childhood only" and "active
asthma" groups presents the most difficult problem: the
asthmatic who wheezes infrequently, or uses a bronchodilator
or steroid medication occasionally, or who feels normal and
well-controlled with routine (not-for-symptoms) inhaled
medication. This might include the asthmatic with
exercise-induced asthma who has learned to prevent symptoms
with inhalation medication. On theoretical grounds, this
person should probably not take up scuba diving, although
there are no compelling data to support this position. Patients
with inactive asthma who wish to dive should have a physical
exam, chest x-ray and a test of vital capacity (spirometry). As
explained above, these tests should show no demonstrable
abnormality.
Some physicians recommend specialized pulmonary function
tests, including exercise tests and something called "inhalation
challenge," which involves inhaling an asthma-provoking drug
in the pulmonary function lab. Only people susceptible to
asthma attacks react to this drug; the rest of the population
does not. The idea with both tests is to induce a potential
asthmatic to have an attack under stressful or abnormal
conditions; if an attack occurs under stressful conditions in the
lab, diving would then be considered too risky an activity.
That is the theory, but I don't believe these asthma-provoking
tests are particularly useful for answering the question about
diving. Simulation of what may happen in the water cannot be
had by exercising someone on a treadmill or having them
inhale a noxious agent in the lab. There are no studies showing
that these "stress" tests are any more useful in answering the
asthma question than are the basic tools available to all
doctors: a test of vital capacity (spirometry), a careful history
and a good physical examination. (Still, since the issue is
unsettled either way, some doctors may choose to rely upon
stress tests to reach a decision.)
WHAT IS THE INFORMED CONSENT APPROACH?
For the inactive asthmatic who wishes to take up scuba diving, I
recommend an "informed consent" approach. He or she should
receive an explanation of the theoretical risks. I have already
explained that many people with "inactive asthma" do dive, but
that doesn't mean it is safe. The would-be diver needs to
understand that air flow obstruction might increase the risk of
barotrauma, and that stressful conditions (cold water,
strenuous activity) could trigger an asthma exacerbation.
Particularly, the potential diver should understand that open
water conditions are very different from the swimming pool
(where scuba training initially takes place), and may lead to
problems not encountered in the more benign pool
environment (Martindale 1990).
Ultimately, the decision should be left up to the individual.
How is this done? After the risks are explained, he or she must
re-affirm their wish to dive. Then, if a note is required by the
training agency, the examining physician should not sign or
offer any statement that diving "is safe" for the individual, but
instead write a brief note summarizing the patient's condition.
The note should state that the patient's asthma history is not a
prohibition to diving and that the potential diver understands
the risks. Diving is inherently a risky activity anyway, so this
type of informed consent makes sense. As example only, I
recommend the type of note shown below.
TO: WHOM IT MAY CONCERN XYZ SCUBA TRAINING
AGENCY I have examined patient John/Jane Doe on June 15,
19--. He/she has a history of inactive asthma, and requires no
medication to treat symptoms. His/her lung exam, chest x-ray
and breathing test (spirometry) are normal. I see no reason why
he/she cannot engage in scuba diving. We have discussed the
risks inherent to all scuba divers. He/she understands that any
tendency to an asthma attack on or under the water might
increase those risks, particularly for fatal air embolism.
He/She has chosen to continue with dive training, and I see no
medical reason to prohibit him/her from scuba diving at this
time.
[Signed, MD]
It is important to emphasize that the physician should never
approve an asthmatic for "shallow water diving only."
Barotrauma is actually more apt to occur closer to the surface
than in deeper water. This is because the greatest pressure
changes occur near the surface. From 33 feet depth to the
surface, ambient pressure decreases 100%, whereas from 66 to
33 feet the pressure decreases only 50%.
If a note is not required for the training agency, the patient
might still be asked to sign such a statement to keep in the
medical file. This will indicate that the physician and the
patient discussed the issues, and that an informed decision was
made by the patient.
Some people have criticized this approach, on the grounds that
individuals referred to a doctor deserve a medical decision on
whether they should or should not dive. One doctor stated,
"Either you are going to take responsibility for the situation or
you are not. To try and leave the decision up to the individual
or agency is not only inappropriate but not serving the patient
very well."
I strongly disagree with this attitude, and believe it is one
reason most doctors seem reluctant to get involved in this
issue. For a doctor to simply tell a patient with asymptomatic
asthma that he or she can or cannot scuba dive, given all the
data I have presented, implies that the physician has a crystal
ball. The patient could rightly infer that "Dr. X said it is OK to
dive so I assumed it was safe." This approach would place an
impossible burden on the examining doctor, especially when
the activity is inherently risky.
I believe this critic's comment reflects an outdated,
paternalistic attitude, one that the practice of medicine has
moved away from over the years. In fact, if a patient with
inactive or childhood-only asthma is clueless as to the risks,
seems unable to accept his or her own responsibility for diving,
and has a "You're-the-doctor-tell-me-what-to-do" attitude, I
would not be able to write the kind of letter shown on the
previous page. Such a patient would simply not receive my
sanction for scuba diving.
In summary, a patient with inactive asthma, who wishes to
scuba dive, should be approached with an open mind. The
theoretical risks should be explained. A physical exam, detailed
medical history, and perhaps a chest x-ray and simple test of
lung function (spirometry) may be all that are needed to reach
a reasonable assessment; the exam and basic tests should be
normal. If there are any questions regarding subtle
abnormality, the applicant should be referred to a diving
medicine specialist.
I realize the safest approach (for doctor and patient) might be
to "just say no." However, such a dogmatic response might lead
some people to seek a more favorable second opinion, or to file
a new medical questionnaire with a different dive shop and omit
the asthma history.
WHAT ABOUT MEDICOLEGAL CONCERNS?
Underlying any evaluation for diving fitness is concern about
legal liability. The agency and scuba instructor are wary of
being sued if one of their trainees has a mishap. The trainee
signs all kinds of waivers, but pieces of paper don't always
eliminate the possibility of lawsuit.
Doctors, of course, are always concerned about malpractice
suits and protect themselves with malpractice insurance. But
nobody wants to be sued; it is painful even when you are
insured and have done nothing wrong. Doctors win about 80%
of all malpractice cases that come to trial, but each "won" case
still leaves a trail of stress, lost work time, and a demoralized
feeling.
Even when a doctor is named in a lawsuit from which he or she
is eventually dropped (50 out of every 100 initial claims are
dropped with no further action), the whole process takes from
one to three years and costs thousands of dollars. Until the suit
is dropped against the doctor, he or she must report the
existence and nature of the lawsuit on every professional
application, such as for hospital staff privileges, renewal of
existing privileges, licensure renewal, etc. For the sloppy lawyer
who files a merit less lawsuit, there is no penalty.
Understandably, some doctors figure it is not worth "taking a
chance" on a lawsuit by passing judgment on a patient for scuba
diving. Other doctors feel that "just saying no" is the safest
route, since that stance surely eliminates any legal risk. This is
unfortunate, because the risk in most cases should be with an
informed diver, not with the training agency or the doctor.
Surely, if the training agency lies to the trainee, or the doctor
gives false assurances that might be actionable. Such is rarely, if
ever, the case. Agencies are explicit in explaining to trainees
the potential hazards of scuba diving, and all trainees sign
informed consent waivers of one sort or another. Physicians
certainly have nothing to gain monetarily or otherwise by
inducing someone to dive.
This is not to say that concern about liability is misplaced.
Even if the doctor does his or her best to fully inform about the
risks, an accident is an accident, and an enterprising lawyer will
look for someone to blame (except the diver, of course). So
medico legal concerns are real and something we all have to live
with. For the doctor, there are three options: stay out of the
arena altogether; say "no" without performing a thorough
evaluation; or evaluate and fully inform the patient about the
potential risks (preferably in a face to face meeting, with clear
documentation about the communication). For the potential
diver, I believe there is only one option: become fully informed
about the risks of diving, not dive when ill or unfit, and strive
to make every dive as safe as possible.
REFERENCES AND BIBLIOGRAPHY Quoted sources and
general references are listed by section or sections, in
alphabetical order. An asterisk indicates references that are
especially recommended. Medical textbooks and journal articles
can be obtained from most public libraries via inter-library
loan.
Bove AA, Neuman T, Kelsen S, Gleason W. Observations on
asthma in the recreational diving population. (Abstract).
Undersea Biomedical Research 1992;19(Suppl.):18.
Butler BD, Hills AB. Transpulmonary passage of venous air
emboli. J Appl Physiol 1985; 59:543-47.
Corson KS, Dovenbarger JA, Moon RE, Bennett PB. Risk
assessment of asthma for decompression illness. (Abstract).
Undersea Biomed Research 1991;18 (Suppl.):16-17.
Corson KS, Moon RE, Nealen ML, Dovenbarger JA, Bennett PB.
A survey of diving asthmatics. (Abstract).
Undersea Biomed Research 1992;19 (Suppl.):18-19.
DAN 1992. Fitness for Diving. Divers Alert Network, Duke
University, 1992.
Davis JC, Bove AA, Struhl TR. Medical Examination of Sport
Scuba Divers, 2nd edition, 1986. San Antonio, Tx: Medical
Seminars, Inc.
Denison D. Disorders associated with diving, in Murray JF,
Nadel JA, eds., Textbook of Respiratory Medicine, W.B.
Saunders Co., Philadelphia, 1988.
Divers Alert Network 1992 Report on Diving Accidents &
Fatalities. Divers Alert Network, Box 3823, Duke University
Medical Center, Durham, NC 27710; 1994.
Edmonds C. Asthma and diving. SPUMS Journal 1991;21:70-74.
Edmonds C, McKenzie B, Thomas R. Diving Medicine for Scuba
Divers. J.L. Publications, Melbourne, 1992.
Edmonds C, Lowry L, Pennefather J. Diving and Subaquatic
Medicine. Butterworth Heinemann, Oxford, 1992.
Farrell PJS, Glanvill P. Diving practices of scuba divers with
asthma. Brit Med J 1990; 300:166.
Glanvill P, Farrell PJS. Scuba divers with asthma. (Letter). Brit
Med J 1990;300:609-10.
Greer HD. Neurological Consequences of Diving. Chapter 19 in:
Bove AA, Davis JC, eds. Diving Medicine, 2nd Edition. W.B.
Saunders Co., Philadelphia, 1990.
Harrison LJ. Asthma and diving. Florida Med J 1991;78:431-33.
Melamed Y, Shupak A, Bitterman H. Medical problems
asso-ciated with underwater diving. New Engl J Med
1992;326;30-5.
Hickey DD. Outline of medical standards for divers. Undersea
Biomed Res 1984;11:407-32.
Jenkins C, Anderson SD, Wong R, Veale A. Compressed air
diving and respiratory disease. Med J Austr 1993;158:275-79.
Lin LY. Scuba divers with disabilities challenge medical
protocols and ethics. The Physician and Sports Medicine
1987;15:224-35.
Linaweaver PG, Jr. Asthma and diving do not mix. Pressure,
June 1982, pages 6-7.
Linaweaver PG, Vorosmarti J. Fitness to Dive. Thirty-fourth
Undersea and Hyperbaric Medical Society Workshop, May 1987.
UHMS, 9650 Rockville Pike, Bethesda, Maryland 20814.
Linaweaver PG, Bove AA. Physical examination of divers.
Chapter 25 in: Bove AA, Davis JC; Diving Medicine, 2nd
Edition, W.B. Saunders Co., Philadelphia, 1990.
Marraccini JV, Friedman PL. Scuba death due to asthmatic
bronchitis, air embolism, and drowning. Forensic Pathology
No. FP 86-6 (FP-149) 1986;28:1-4.
Martin L. The medical problems of underwater diving. (Letter).
New Engl J Med 1992;326: 1497.
Martindale JJ. Scuba divers with asthma. (Letter). Brit Med J
1990;300:609.
McAniff JJ. United States Underwater Diving Fatality Statistics,
1989. Report No. URI-SSR-91-22. University of Rhode Island,
National Underwater Accident Data Center, 1991.
Mellem H. Emhjellen S, Horgen O. Pulmonary barotrauma and
arterial gas embolism caused by an emphysematous bulla in a
SCUBA diver. Aviat Space Environ Med 1990:61:559-62.
Millington JT. Physical standards for scuba divers. J Am Board
Fam Pract 1988;1:194-200.
Neuman T. Pulmonary Considerations I, in Linaweaver PG,
Vorosmarti J. Fitness to Dive. Thirty-fourth Undersea and
Hyperbaric Medical Society Workshop, May 1987.
Undersea & Hyperbaric Medical Society, 10531 Metropolitan
Ave., Kensington, MD 20895.
Neuman TS, Moon RE. Are people with asthma fit to dive?
Pressure, November/December 1991, page 3.
Neuman TS. Pulmonary Disorders in Diving. Chapter 20 in:
Bove AA, Davis JC; Diving Medicine, 2nd Edition, W.B.
Saunders Co., Philadelphia, 1990.
Neuman TS, Bove AA, O'Connor RD, Kelsen SG. Asthma and
Diving. Annals Allergy, 1994;73:349.
Schanker H, Spector S. Relationship between asthma and scuba
diving mortality. (Abstract). J Allerg Clin Immunol
1991;81:313.
Smith TF. The medical problems of underwater diving. (Letter).
New Engl J Med 1992; 326,1497-8.
Strauss RH. State of the art: Diving medicine. Am Rev Resp Dis
1979;119:1001-23.
Watt SJ, Gunnyeon WJ. Scuba divers with asthma. (Letter). Brit
Med J 1990; 300:609.
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