Commercial Diving Medical Standards

The professional or commercial diving encompasses a broad range of divers including the military diver, the offshore oilfield saturation diver, the recreational diving instructor, the photojournalist, the scientific diver and the police diver.Whilst their scope of div­ing varies markedly, what they do have in common is that they are employed and receive financial gain from their diving.

 All commercial divers should receive appropriate training in order for them to carry out their task, be capable of dealing with emergencies involving them­selves or their buddy, and be able to operate in the face of demanding environmental conditions. The diver who is paid to get the job done, does not have the luxury of deciding when he will dive. The profes­sional diver is often only one part of a team. He must be able to replace, and be replaced by, other members as the task demands.

Most deviations from the norm make for compli­cations. A diver who is less physically strong than the others will sooner or later be exposed to conditionswhich he will be unable to handle. The professional diver must be able to perform all the diving tasks expected of the team as a whole, and not have any specific restrictions or limitations imposed on him or his diving practice.

When assessing a candidate's fitness for commer­cial diving the doctor is usually constrained by gov­ernmental regulations or by commercially agreed standards. The doctor has to consider the position of the employer as well as the diver, and has less scope for including the potential candidate in a discussion of risk factors. The doctor must also consider any legal aspects/compensation liabilities that may arise in the future.

In most industrialized countries workplace regu­lations dictate that the employer has a duty of care to ensure that all diving carried out is as safe as is rea­sonably practicable. The diver also has a responsibil­ity to declare if his fitness to dive is compromised for any reason.

Anti-discrimination laws now require statistically sound scientific-based evidence to support the exclu­sion of a worker from a particular occupation on medical grounds (best diving). It is therefore important that the medical practitioner who undertakes commercial diving medical examinations has an in-depth know­ledge of the particular workplace and environmental conditions under which the diver will operate.

In general, the minimum standards for commer­cial divers are similar to those that apply to recre­ational divers. Because these medicals are required at regular intervals, usually annually, the original or baseline data - both clinical and investigatory - allows for comparison with the current assessment and the detection of adverse health effects.

Physical Fitness Standards and Diving

Physical fitness standards are often contentious and have effectively excluded women from the realms of military diving. Professional diving is arduous and involves heavy equipment - one of the rebreather units used by many of the world's navies weighs 29 kg on land when fully charged. Not many women are capable of lifting and carrying this type of load on land, and neither can some men! Fitness tests have long been detailed in terms of aerobic performance (i.e. a 2.4-km run in under 10 minutes) and tests of upper body strength (push-ups or chin-ups). How­ever, these types of test give no indication of an indi­vidual's ability to do a specific occupational task.

Fitness tests should be performance-based, reflect the nature of the activity, and be job-specific. For example, if the job requires the diver to climb into a small boat wearing a 30-kg set, the test should beexactly that. Swimming ability should be assessed as opposed to running speed. Professional divers also need to have sufficient physical reserves in order to respond to changing environmental conditions and to respond to emergencies.

Age and Commercial Diving

Most authorities agree on 18 years as the minimum age for entry into the commercial diving world. This is also realistic when considering the time required for the prerequisite training for bell divers or the age limits in place for enlisting in the military or police forces. It is unlikely that a scientific diver will have the necessary educational qualifications at less than 18 years of age. These general limits on entering the workforce exist to ensure the potential employee has sufficient emotional and physical maturity to accept the responsibility of the job.

There is no upper limit of age for professional divers, but like recreational divers the risks of cardio­vascular disease with aging must be considered. Physical fitness declines with age, along with the ability to recover from injury. The medical practi­tioner must make some assessment of the aging diver's pulmonary and cardiovascular reserves, and also his ability to continue to perform all required tasks. As the diver ages, his experience may be used to more benefit in a diving supervisory role.

Skin and Commercial Diving

Saturation divers may spend days to weeks at depth, living in a habitat at or close to their working depth. These habitats are often hot and humid and can be an incubator for bacterial skin infections. Divers often share equipment such as wetsuits and regula­tors. Wet skin can promote the spread of bacteria normally confined to intertriginous zones. Common fungal infections such as tinea pedis require treat­ment to prevent the entire diving team from becom­ing infected. Molluscum contagiosum, because of its high infectivity, requires treatment before a diver is declared fit to dive. Herpes simplex is relatively com­mon in the general community and will not harm the diver; however, if oral lesions are so widespread and painful that holding a mouthpiece becomes dif­ficult then the diver should be made temporarily unfit to dive. Herpes zoster infections will make the diver unfit to dive until he is no longer infectious and the pain and lesions have settled.

Allergic contact dermatoses occur in divers. Antioxidants and glues used in the manufacture of neoprene wetsuits and drilling muds have been impli­cated, and require assessment by a dermatologist. As all future exposure to the allergen must be avoided this can have serious effects on the diver's future.

Vision and Commercial Diving

The commercial diver often works in such low visi­bility environments that he uses his hands to 'see'. However, the diver must be able to read gauges, watches and decompression tables. Contact lenses may be used to correct vision, although hard lenses should be avoided due to the risk of corneal ulcera­tion secondary to the formation of bubbles beneath the lens. This risk is reduced if fenestrations are drilled through the lenses.

Colour vision is not essential to diving, although there will be some exceptions, e.g. military explosive ordnance divers who require normal colour vision to distinguish between the red and the green wire!

Ear, Nose And Throat - Commercial Diving

Exostoses are particularly common in subjects who spend extended time in cold seawater. The diver is rendered temporarily medically unfit by the presence of acute or chronic otitis externa, which is particu­larly troublesome in chamber operations (see 'Skin' above).

Round window fistula secondary to inner-ear barotrauma has in the past resulted in an automatic disqualification from diving. There is no doubt that individuals who have persistent labyrinthine symptoms such as vertigo, dizziness and loss of balance should not resume diving.

However, in divers who have made a full recovery (with either conservative or surgical management) there are some diving physicians who would con­sider them fit to dive. This requires careful consid­eration based upon the audiological outcome, and detailed and informed advice must be provided to the diver. Forceful autoinflation must be avoided at all times.

Hearing and Commercial Diving

The commercial diver must be able to communi­cate and understand verbal instructions. Most commercial diving standards require an annual audiogram covering the frequency range from 250 to 8000 Hz.

It had been considered for many years that pro­fessional divers suffered from an accelerated form of hearing loss. However, many of these studies failed to take into account the diver's exposure to workplace noise in addition to his diving exposure. For exam­ple, naval divers were exposed to gunfire and engine room machinery noise. With advances in the man­agement of industrial noise exposure the diver should not be at increased risk of hearing loss from these extraneous causes.

Diving exposure may result in hearing loss as a consequence of inner-ear barotrauma and inner-ear decompression sickness. There is also some experi­mental evidence of cochlear degeneration in animals that have been subjected to accepted compression/ decompression schedules. Therefore, the appearance of hearing loss (particularly a unilateral loss) should be evaluated carefully. At the time of the annual medical it is also appropriate to provide specific advice to the diver on the importance of using appropriate hearing protection in designated high- noise areas.

Nervous System and Commercial Diving

A detailed examination of the nervous system is mandatory, and should be normal. The presence of any neurological disease is grounds for rejection, especially progressive, relapsing or intermittent conditions. The exception to this rule will be any well-documented, non-progressive abnormality such as a patch of anaesthetic skin, provided that generalized disease is excluded.

Gastrointestinal System

The commercial diver is often required to work in remote areas, in the absence of qualified medical support. A perforated peptic ulcer is a medical emer­gency at the best of times, but is a life-threatening emergency on an isolated diving platform or during a saturation dive. Similarly, treatment of an acute exacerbation of inflammatory bowel disease may cost a company dearly if a saturation dive has to be aborted on medical grounds. Serious consideration must be given to the continued fitness to dive of a commercial diver with chronic gastrointestinal disease.

Diabetes and Diving

Diabetes requiring medication is usually considered a contraindication to commercial diving.

Screening For Dysbaric Osteonecrosis

In recent years most diving medical standards have required all professional divers to undergo annual long-bone X-rays as a screening test for dysbaric osteonecrosis. This is no longer required as the incidence of the disease is low, the diver is exposed to a significant radiation dose, and the yield of positive results is low. It is recommended that long-bone screening be carried out on only those divers who are considered to be at increased risk of dysbaric osteonecrosis. These baseline X-rays should be performed once on entry to the profession and be retained for at least the career lifetime of the diver.

If dysbaric osteonecrosis is suspected, then a further series should be taken, guided by the clinical presentation. The films must be comparable, and it is recommended they be performed in accordance with the procedural guidelines laid down by the UK Medical Research Council Decompression Sickness Registry. Alternatively, magnetic resonance imaging is both more informative and carries less risk.

To Diving After Illness Or Injury

A careful assessment of dive fitness is required in any diver who suffers an illness or injury. It is important to consider whether or not the condi­tion impacts on dive safety, and whether the diver can continue to perform his job. Workplace legis­lation requires employers to undertake reasonable and practical steps to provide a safe working envi­ronment for all. The diver who suffers a traumatic amputation of one or more fingers may still be able to handle heavy and bulky underwater tools, act as a standby diver and tend lifelines. If the individual can still demonstrate his proficiency in all these tasks, then continued diving may be possible.

The diving medical practitioner must understand the specific job requirements of particular diving operations in order to be able to provide informed judgements on diving fitness. The diving supervisor can assist the medical practitioner by delineating exact job descriptions. It is equally important to assist the diver who is permanently unfit to dive to understand and accept the reasoning behind the decision.

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