Vol 25 No. 2 / Apr - Jun 1999  

ORIGINAL ARTICLES

A Survey on Diving Medicine and the Family Physician
G C T Chan, E C T Low, J C M Wong

Abstract

Introduction: The role of diving and hyperbaric medicine in Singapore is not well established. This may be due to the lack of awareness and accessibility to training in this discipline. Currently the expertise lies mainly with the medical officers in the Singapore Navy. This paper discusses the relevance of diving medicine to general practitioners.

Study objectives

1. To determine the prevalence of encounters with diving related conditions
2. To identify the knowledge base of diving with respect to performing ‘Fitness to Dive’ examinations
3. To discuss the role of the Singapore general practitioner in diving medicine

Method

A prevalence study employing a self-addressed questionnaire was sent to the doctors listed with the College of Family Physicians Singapore over a 2 month period.

Results

There were 191 responses (response rate 23.8%). The respondents showed that 116 (61.1%) had done a diving medical assessment for recreational divers; 20 (10.5%) had done examinations for commercial divers; 7 (3.7%) knew the absolute contraindications to diving; and 173 (91.1%) felt they lacked adequate knowledge to manage diving related problems. With respect to hyperbaric oxygen therapy (HBOT), 167 (87.8%) were aware of HBOT; 32 (16.8%) were aware of the proven indications for HBOT; and 171 (90.0%) felt they did not have enough knowledge about HBOT to advise the patient. 146 (76.8%) expressed the need for CME in diving and hyperbaric medicine.

Conclusion

There is a role for GPs in the prevention and management of diving accidents. The answers to the questions suggest that the current knowledge base in diving medicine may be inadequate to evaluate fitness to dive and to manage diving accidents. It would be useful for CME in diving and hyperbaric medicine to be developed for GPs.

Keywords

General practitioners, diving medicine, knowledge base

Acknowledgments

The authors would like to express their thanks the College of Family Physicians Singapore and the general practitioners for their support in this project.

Introduction

With the increasing number of recreational divers¹, primary health care doctors, especially general practitioners (GPs), will likely do more pre-diving assessments to determine fitness to dive and encounter diving related problems in their practice. As information in this area was lacking it was felt that a survey among the GPs in diving medicine may contribute towards the development of diving safety and health in Singapore.

Objectives

The aim of this survey was to determine whether diving medicine was relevant to the GP.

Materials and Methods

At the time of the survey there were about 1200 General Practitioners in Singapore of which 800 were registered with the College of Family Physicians². A self-addressed questionnaire was sent to the doctors listed with the College and the responses were collected over a 2 month period in November and December 1997. There were a total of 191 responses or 23.8% response rate.

The objective of the questionnaire was to gain an understanding of the knowledge base of GPs in assessing fitness to dive by asking about the absolute contraindications to diving. It also included a section for them to identify what the recognised indications for hyperbaric oxygen therapy (HBOT) were. The respondent had to indicate the appropriate choice of answers; this was usually more than one answer. The correct responses were based upon the policies of three international bodies for diving and hyperbaric medicine: the Undersea and Hyperbaric Medicine Society (UHMS),³ the European Committee for Hyperbaric Medicine⁴ and the South Pacific Undersea Medicine Society.⁵ It should be mentioned that the response to the questions requires a basic understanding of diving hyperbaric medicine.

There were also direct questions on diving-related encounters i.e. doing fitness to dive examinations or treating diving related conditions. The respondent also gave their opinion on whether they had adequate knowledge to manage diving accidents and to advise patients about HBOT. Finally, they were asked whether there was a need for Continuing Medical Education (CME) in diving medicine for GPs.

Results

(Refer to Table 1 for a summary of survey results)

Assessing fitness to dive

One hundred and sixteen (61.1%) respondents had done a diving medical assessment for recreational divers; while 20 (10.5%) had also done examinations for commercial divers.

Encounters with diving related problems

Fifty-six (29.5%) respondents had encountered patients with diving related problems. Table 2 shows the range of conditions seen by the respondents and the percentage of respondents who have seen such conditions.

Knowledge of diving medicine

The respondent had to indicate what he felt were absolute contraindications to diving based on a list of medical conditions. The most appropriate answers required were: ‘sickle cell anaemia’, ‘respiratory tract infections’ and ‘asthma’.^3,4,5,6 Table 3 shows the number of responses given for the various proposed conditions . The other conditions such as ‘hypertension’, ‘diabetes mellitus’ and a ‘previous history of decompression illness’ were generally relative contraindications (according to the severity of the condition - only the most severe and poorly controlled cases, as well as insulin-dependent diabetes were absolute contraindications to diving). An upper age limit of 45 i.e. chronological age is not a contraindication at all.^3,4,5,6 Only seven respondents (3.7%) indicated all the appropriate answers.

In response to a scenario where a diver presents to the physician with symptoms suggestive of decompression illness, 48.4% would refer to a diving physician for management. One hundred and seventy-three (91.1%) respondents felt they lacked adequate knowledge to manage diving related problems.

Hyperbaric Oxygen Therapy (HBOT)

One hundred and sixty-seven (87.8%) respondents indicated an awareness of HBOT.

The questionnaire tested the physicians on their knowledge of HBOT applications. This question was felt to be relevant to GPs because they would be the contact person for patients inquiring about HBOT and its applications. The recognised indications listed were ‘carbon monoxide poisoning’, ‘radiation tissue damage’ and ‘diabetic ulcers’.^7,8,9,10 (Table 4 shows a list of approved indications for HBOT) HBOT has not been found useful for ‘cancer’ and ‘cosmetic uses in intact skin’.^7,10 Thirty-two (16.8%) respondents were able to provide the required answers; while 6.3% believed that HBOT has use in ‘cosmesis’ and ‘cancer’. One hundred and seventy-one (90.0%) respondents felt they did not have enough knowledge about HBOT to explain to patients regarding its benefits, application and side-effects. It was also found in response to a direct query, 118 (62.1%) respondents would refer patients for HBOT for the following conditions listed in Table 5.

Need for CME

One hundred and forty-six (76.8%) respondents felt the need for CME in diving and hyperbaric medicine for GPs.

Discussion

The number of cases referred for the treatment of diving emergencies and hyperbaric oxygen therapy has been increasing over the years in the Naval Medicine and Hyperbaric Centre, Republic of Singapore Navy.¹¹ It was also significant to note that in the case of diving treatment patients, about 75% were recreational divers.¹¹ Although statistics were not available for Singapore, diving appears to be increasingly popular as a leisure sport among its population.

61.1% of the respondents had conducted diving medicals for recreational divers; of which 10.5% had also conducted them for commercial divers. However, the biggest limitation in this study was the low response rate. Of the 800 questionnaires sent, 190 respondents replied, making a response rate of 23.8%. This may suggest that the doctors only had an interest in diving medicine if it was related to the nature of their practice.

Knowledge in diving and hyperbaric medicine

Although 61.1% of the of the respondents had done diving medicals for patients, only 3.7% of them could correctly indicate (the 3 responses required) the absolute contraindications to diving. Based on the respondents’ answers, 53.2% and 37.4% could be hypothetically clearing fallaciously asthmatics and those with sickle-cell anaemia fit for diving. Asthmatic attacks may be precipitated by a number of factors, including physical exercise, salt-water aspiration and the breathing-in of cold, dry air from the breathing apparatus.^6,12,13,14 An asthmatic attack underwater is extremely dangerous and may induce panic. Pulmonary barotrauma could also result from a combination of air-trapping and rapid ascent. Sickle cell disease predisposes to a sickling crisis under hypoxic conditions. It will be catastrophic in remote localities or under hyperbaric conditions. It may also complicate the management of decompression illness.^13,14 Thus candidates with sickle-cell disease or trait should be discouraged from diving.

Conversely, not certifying the candidate fit to dive for reasons of ‘hypertension’ and ‘being over 45 years of age’ may be inappropriate.^12,13 A patient with mild or well controlled hypertension (uncomplicated) need not be excluded from diving. Chronological age is a significant selection criteria in military diving,¹⁵ but it need not be in recreational diving. It is difficult to determine what the upper limit for recreational diving is, and in the examination of the elderly diver, it is more important to identify the effects of ageing and the presence of underlying disability.^12,13

Where a diver presents to the physician with symptoms suggestive of decompression illness, only 48.4% indicated that they would refer the patient to a diving physician for management. The definitive treatment for decompression illness is recompression treatment and the use of hyperbaric oxygen.^3,4,7,10. It is thus advisable that all cases of suspected decompression illness be referred to a hyperbaric chamber facility for management. Although HBOT awareness was present in 87.9% of the respondents, there appeared to be a lack of understanding about its applications which could be due to the lack of information on HBOT locally. This need for CME on Diving and Hyperbaric Medicine was recognised by the doctors themselves. In 91.1% and 90.0% of the respondents, the survey indicated that they did not have sufficient knowledge about diving and hyperbaric medicine respectively; and 76.8% recogonised the need for CME for doctors in this field.

The role of GPs in diving medicine

It is compulsory for compressed air workers to undergo pre-employment and periodic examinations by law in Singapore.¹⁷ Professional divers in the navy also require similar examinations. There is currently no legislative requirement for medical screening for recreational divers.

This, however, does not exclude the relevance of basic diving medical knowledge for GPs. It is the opinion of the authors that family practitioners do have a role in the Singapore diving community. The respondents in the survey have shown significant encounters with diving cases, but their answers have also revealed a gap in the knowledge in assessing fitness to dive and management of decompression illness. Whether GPs are deficient in the other aspects of diving medicine such as the management of dangerous marine animal bites or stings and management of barotrauma, will probably require further evaluation.

The main role of GPs in diving medicine is largely in the prevention and management of diving accidents and diving related conditions.¹⁸ They should also have a responsibility in the follow-up of these patients post-treatment.

The prevention of diving related conditions/accidents18

There is usually a requirement for potential divers to have a medical examination prior to starting diving lessons. This is usually on the diving school’s own initiative to prevent diving incidents (and perhaps liability claims). GPs thus have a role in screening diving candidates to assess for contraindications to diving (examples include psychological immaturity in young divers to manage a diving emergency and poor cardiovascular fitness to overcome work in diving) and for medical conditions which may be aggravated by the diving environment (a good example is that of asthma, which may be aggravated by multiple triggering factors). The risk of an accident is reduced by certifying them unfit or giving the appropriate medical advice and precautions during diving. He will also moderate various drug usages in divers to minimise adverse drug effects or interactions which may compromise the diver’s performance and safety.

It is therefore necessary for GPs to be aware of diving illnesses and to be able to prescribe with care for divers to avoid harmful side effects. Local knowledge of diving sites (such as geography, nearest recompression chamber facility, modes of evacuation) can also be useful when advising novices and preparing them for a diving emergency. As some dive sites in South East Asia have a risk of communicable diseases such as malaria and typhoid, preventive medicine advice and immunisation is a relevant area for the diver in Asia.

During a diving incident/accident18

Divers get into trouble at sea or in lakes and GPs on-site or who take a call are often involved in the first aid treatment and the making of a correct diagnosis. The GP would need to be able to contact expert advice about further treatment and decide how to act on further advice. This usually involves organising transport, stabilising the patient’s condition for transfer, arranging for recompression therapy, giving oxygen and fluids and keeping clinical records of the patient’s condition, drugs and fluids administered.^18,19

In general, recreational divers from Singapore would dive in sites outside the country due to the lack of ‘exciting’ diving spots locally. These divers would often present late and it may be difficult to elicit a past history of diving (days before) and diagnosis becomes more challenging.¹⁸ A high index of suspicion is warranted to avoid missing diving-related problems. The lack of diving medical awareness could also result in the GP referring a case of diving accident to the hospital when the patient would probably have benefited more from a referral directly to the diving physician.* This delay could affect the prognosis in decompression illness even with definitive recompression therapy.¹⁴ It is thus important that the family physician needs to recognise a medical condition related to diving; and even if he does not have the means to manage the condition, he should be able to seek advice and make the appropriate referral.

After the diving related condition/accident18

After a diving incident, the patient needs to be followed up to detect residual disease, its recurrence and sometimes delayed complications of the disease (eg personality changes and dysbaric osteonecrosis in decompression illness). If the patient wants to return to diving, he should be assessed on his fitness to dive. In this respect, referral to a diving physician may be necessary.

References

1. Divers Alert Network. Report on diving accidents and fatalities. New York: Divers Alert Network, 1996
2. Unpublished information from the College of Family Physicians Singapore 1997
3. Undersea and Hyperbaric Medical Society. Hyperbaric oxygen therapy: A committee report. Bethesda: UHMS Inc, 1996
4. European Committee for Hyperbaric Medicine. ECHM Consensus Conference: Approved indications for hyperbaric oxygen therapy. ECHM Inc, 1994
5. South Pacific Underwater Medicine Society. The SPUMS diving medical. SPUMS Inc, 1991
6. Elliot DH(Ed). Medical assessment of fitness to dive: Proceedings of an International Conference at the Edinburgh Conference Centre 8-11th March 1994. Biomedical Seminars, 1994
7. Kindwall EP. Uses of hyperbaric oxygen therapy in the 1990s. Cleveland Clinic Journal of Medicine 1992: pp517-528.
8. Rabkin JM and Hunt TK. Infection and oxygen. In: Davis JC, Hunt, TK (Eds). Problem wounds: The role of oxygen. New York: Elsevier Science Publishing Co 1988: 1-16
9. Hammarlund C. The physiological effects of oxygen. In: Kindwall E (Ed). Hyperbaric Medicine Practice. Wisconsin: Best Publishing 1995:17-32
10. Gorman D. The therapeutic roles of oxygen. In: Gorman D (Ed). Diving and hyperbaric medicine. Royal Adelaide Hospital, South Australia 1996: 31.1-31.6
11. Naval Medicine and Hyperbaric Centre. Report on trends of diving related conditions treated at the Naval Medicine & Hyperbaric Centre. Republic of Singapore Navy: Unpublished, 1997
12. Linaweaver PG and Biersner RJ. Physical and psychological examination for diving. In: Shilling CW, Carlston CB and Mathias RA (Eds): The Physician’s Guide to Diving Medicine. New York: Pleum Press 1991: 32-45
13. Davis JC (Ed). Medical Examination of Sports Scuba Divers. San Antonio, Texas: Medical Seminars Inc, 1986
14. Edmonds C, Lowry C and Pennefather. Diving and Subaquatic Medicine. Sydney: Butterworth & Heinnman, 1991
15. Naval Medicine and Hyperbaric Centre. Medical standards for naval divers. Republic of Singapore Navy: unpublished. 1997
16. Kindwall E. Contraindications and side effects to hyperbaric oxygen treatment. Kindwall E (Ed). Hyperbaric Medicine Practice. Wisconsin: Best Publishing, 1995: 45-56
17. The Factories Act:The Factories (Medical Examinations) Regulations. Singapore: Ministry of Labour, 1985
18. Smith PC. The GP’s role in dive accident management. SPUMS J (Supplement) 1998;28 (9): 9-10
19. Gorman D, Richardson D, Davis M et al. The SPUMS Policy on the initial management of diving injuries and illnesses. SPUMS J 1997;27 (4): 193-200

Table 1. A summary of the survey results

Table 2. Types of diving related conditions seen by respondents

Table 3. List of percieved absolute contraindications to diving by respondents

*indicates the true absolute contraindications

Table 4. Recognised applications of Hyperbaric Oxygen Therapy (approved by Undersea Hyperbaric Medical Society)

Table 5. Conditions which respondents would refer for HBOT