Elective experience: getting into the red

Kevin Bailey describes his experience of diving medicine at the Red Sea

There seems to be a bit of colour confusion surrounding the Red Sea. Why it is so called is a mystery. Some say it is due to the light of the setting sun reflecting off the red mountains along its shore and on to the surface of the water. Others say that it should have been called the "Reed Sea" because of the abundant reed beds near Suez before the canal was built. Some claim the name refers to the "red tide" of a plankton bloom (Trichodesmium erythraeum) that turns the water brown when it dies. The Ancient Egyptians knew the Red Sea as the Wadge Wir (the Great Green)--not very red at all. Anyway it looked blue to me, and I spent a lot of time in it. But I digress. I didn't spend my elective researching the origins of the Red Sea's name, rather hyberbaric medicine at the sea's main diving resort, Sharm El Sheikh.

Hyperbaric medicine is a specialty traditionally associated with the military, although the explosion in numbers of recreational divers in recent years has brought a need for greater numbers of civilian specialists. This, and speedy world travel, means that the complications of diving may present to doctors many miles away from diving centres. For this reason it is essential for doctors, whatever their specialty, to have some knowledge of the contraindications and complications of diving. Personally, I chose it as part of my elective study period because I love to dive and have never dived in the Red Sea before. I was not disappointed.

The diving resort
Sharm El Sheikh is a resort on the southern tip of Egypt's Sinai Peninsula, and is the busiest diving centre on the Red Sea. In 1984 it offered only one hotel and a handful of dive operators. Now the resort is a sprawling concrete strip wedged in between the sea and the pink Sinai Mountains, supplied by its own airport. Although giving the feeling of living on a vast building site, Sharm offers unequalled access to the major dive sites of the northern part of the Red Sea and therefore attracts thousands of sports divers throughout the year.

Diving medicine
Recreational diving has its fair share of accidents. Ensuring that the participant is physically eligible to dive can prevent many of these; others such as hypothermia or overexertion caused by adverse water conditions can be avoided by proper dive planning. Even attack by hazardous marine life can be avoided by simple measures (such as not touching them). Certain diving maladies can happen to anyone due to the physiological effect of descending to pressure. These include barotraumas to air filled spaces in the body, such as the external, middle, and inner ear; nasal sinuses; and teeth (as a result of dental work).

Breathing compressed air at depth is a danger to be aware of because of nitrogen narcosis or rapture of the deep, as it is more poetically known. The leading cause of diver fatalities is lung overexpansion injury occurring as a result of diver panic, emergency rapid ascent to the surface, or air trapping due to underlying pulmonary conditions. Less dramatic but also potentially debilitating is decompression sickness caused by the liberation of gas bubbles from solution into tissue or blood, a condition with many presentations that are easily missed by a non-specialist.

The essential job of providing specialist medical care to the dive operators and their charges is the responsibility of the two doctors based at the Hyperbaric Medical Centre. This facility consists of a consulting room, a hyperbaric chamber (basically a large metal tube with an airlock and breathing apparatus) lined up with two air compressors, and a wall full of air storage tanks, squeezed into three sea containers welded together. The chamber is a purpose built unit constructed to the medical centre's specifications, with room for two patients and a medic to tend to them. There are only two indications for recompression: decompression sickness (the bends) and arterial gas embolism (AGE). The rationale behind treatment for both conditions is that breathing 100% oxygen at a specified pressure delivers oxygen to ischaemic/hypoxic tissue and displaces as much inert gas from vasculature and tissues as possible.

The chamber
The chamber is available 24 hours a day, seven days a week, and has never been shut in the eight years that it has been operating; routine maintenance and repairs take place during quiet periods. Although treatment of diving injuries is an important part of the work of the chamber, it serves a far wider role of injury management, with an emphasis on prevention. Local doctors are encouraged to attend lectures covering the basics of diving medicine and recompression treatment, as they are the ones likely to be initially consulted.

Transportation of people with diving injuries can be a hazardous task, and transport providers (helicopter, ambulance, camel) are trained to evacuate the patient in a safe manner--that is, pilots are instructed not to exceed an altitude of 1000 feet, and even transportation over land should take altitude into consideration.

Another aspect of the chamber's work is the medical assessment of holidaymakers wishing to learn to dive, and this was by far the most common reason for consultation while I was there. Unfortunately, for a small number of holidaymakers, having the all clear from their GP back home did not necessarily give them the all clear in Egypt if the local specialist did not consider them fit to dive. He is the one who will have to treat them if they injure themselves.

And finally...
So what did I learn? Well, my basic although sound knowledge in medicine as applied to recreational diving has not only broadened my skills as a doctor, but also made me a safer diver. Additionally, it gave me the opportunity to dive at some exceptional sites and recover after the ordeal of pathology finals, which can't be a bad thing.

Kevin Bailey, preregistration house officer, Epsom General Hospital


studentBMJ 2001;09:357-398 October ISSN 0966-6494