Hi Opalobsidian,
For many years asthma has not necessarily been an absolute contraindication to scuba. A number of persons with this condition now are medically cleared to dive.
Emotionally exacerbated asthma, along with cold and exercise induced ashtma, are among the more problematic forms of the disorder for the diver as emotional stress, physical exertion and cold can occur with scuba. As you will see, the British Sub-Aqua Club (BSAC) does not certify divers whose asthma is triggered by any of these three, and the YMCA asthma protocol requires the ability to tolerate stress without becoming symptomatic and without need for rescue inhalers.
As a general orientation, here's an updated and expanded version of a piece that appeared in my "Dive Workshop" column in "Rodale's Scuba Diving" magazine:
"Can I Dive With Asthma?
Asthma is a chronic but often largely controllable obstructive pulmonary disease that affects about eight to 10 percent of children and five to eight percent of adults in the U.S. Signs and symptoms include shortness of breath, wheezing, tightness in the chest and lasting cough. The potential adverse impact of a severe attack under water is obvious, and could be fatal. Arterial gas embolism (AGE) as a result of air trapping from the constriction and plugging characteristic of this disease has also been a frequent, but as yet inconclusive, concern. The research to date (e.g., 1) suggests that some asthmatics may be at increased risk of pulmonary barotrauma, but the risks do not appear large (e.g., 2).
Asthma Triggers
Asthma is a chronic irritation and hypersensitivity of the respiratory tract, and attacks can be triggered as a reaction to a variety of conditions including stress, cold or exercise, and allergens such certain medications, pollens and foods. The asthmatics body reacts to these triggers, in varying order and severity, by constriction of smooth muscle in the bronchi and bronchioles, inflammation of the airway and increased mucous production. Attacks tend to be recurrent rather than continuous, and there is often much that can be done medically to reverse breathing difficulties when they do occur. In addition, since many of the precipitants of an attack are known, they can be avoided or controlled.
Diving with Asthma
Until the mid-1990s, asthma was largely considered an absolute contraindication to diving. However, thinking in the medical and professional dive community has rather radically altered since then, and those with asthma can now be certified under certain circumstances. Although they differ somewhat, the YMCA (3), UKSDMC (United Kingdom Sport Diving Medical Committee) (4) and (UHMS) Undersea and Hyperbaric Medicine Society (5) each offer protocols guiding medical clearance to dive with asthma.
For example, the YMCA criteria include a requirement that all asthmatics have normal resting and exercise pulmonary function tests with no degradation after exercise. The criteria allow those taking routine preventative medications to be evaluated while continuing their treatment. Also required is the ability to exercise and tolerate stress without becoming symptomatic while on maintenance medications, and the absence of a need for rescue inhalers during times of stress or exertion.
If you suffer from asthma, its clearly unwise to deny or minimize this condition to yourself, or hide it from your instructor or the operators with whom you dive. Scuba can involve some of the asthma triggers discussed above, such as cold and exercise, not mention hyperdry scuba cylinder gas. If you have asthma and want to dive, or are already diving without medical clearance, it is critical that you consult a physician to obtain an appropriate pulmonary workup and permission to dive.
Finally, the issue of being a reliable dive partner must be considered. A diver with ashtma should always inform his buddy of his medical status.
(1) Sports Med. 2003;33(2):109-16.
Asthma and recreational SCUBA diving: a systematic review.
Koehle M, Lloyd-Smith R, McKenzie D, Taunton J.
Allan McGavin Sports Medicine Centre, Department of Family Practice and the School of Human Kinetics, University of British Columbia, Vancouver, British Columbia, Canada.
Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity.There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making.
(2) Int J Sports Med. 2005 Sep;26(7):607-10.
Demographics and respiratory illness prevalence of sport scuba divers.
Tetzlaff K, Muth CM. Medical Clinic and Polyclinic, Department of Sports Medicine, University of Tubingen, Germany.
This study aimed to establish epidemiological data on diving habits and outcome of subjects with respiratory diseases who are considered at increased risk for diving injuries. We conducted a cross-sectional demographics and prevalence study by distribution of an anonymous questionnaire with an issue of a widespread sport diving magazine. The questionnaire was designed to obtain medical and diving history data with an emphasis on respiratory diseases and complaints. The investigational population comprised sport scuba divers of any age and gender from Austria, Germany, and Switzerland. Two hundred and twenty-six male and 96 female divers sent completed questionnaires. Of the respondents 8.7 % indicated that they currently have asthma. Two thirds of asthmatics complained about regular dyspnoea. However, only 42.4 % used drugs relieving or controlling their symptoms regularly and 27.3 % used them in a prophylactic manner before diving. Five percent and 4.7 % of all divers reported a history of respiratory disease other than asthma or dyspnoea respectively. The divers with respiratory illness or complaints had logged a total of 17,386 dives. There were no cases of serious diving injuries. Despite the well-known limitations of postal surveys assessing self reported data, this study indicates that there is a population of subjects diving uneventfully with respiratory diseases that are considered medical contraindications to diving. These subjects deserve particular guidance on related risks and disease management.
(3) YMCA protcol & some background info on diving with asthma:
http://www.ymcascuba.org/ymcascub/asthmatc.html
(4) UKSDMC protocol:
http://www.uksdmc.co.uk/standards/St...- asthma.htm
(5) "Are Asthmatics Fit to Dive?"; Undersea and Hyperbaric Medical Society, 10531 Metropolitan Ave., Kensington, Md. 20895."
An individual with emotionally exacerbated asthma will need to seek clearence for scuba from a diving medicine savvy pulmonologist.
Helpful?
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.
Best regards.
DocVikingo
