Decompression sickness

Abstract

Once a little-understood danger, the 'bends' can now usually be prevented or, if the condition is recognized soon enough, treated successfully. Decompression sickness is caused by the formation of gas bubbles in the blood and body tissues when ambient pressure is reduced. As the diver descends, the increased pressure beneath the surface of the water forces the nitrogen from the air in his lungs into solution in blood ad tissues. Depending on the amount of nitrogen stored, if the subsequent ascent to the surface is too rapid, nitrogen bubbles may form within the body, causing decompression sickness. After several decades of experience and research, there are now guidelines as to how abrupt a reduction in pressure causes the disease. Thus divers, and others exposed to increased pressure, can usually avoid this danger by reducing the pressure gradually. Symptoms and signs, the physical bases of the disease, treatment and prevention are concisely reviewed. A comparison is made of whales, fish and man.