The bends is a painful condition that can occur in scuba divers, in aviators flying at high altitudes, in people working in pressurized settings, and in some other situations. Also called decompression sickness, the bends results when rapidly decreasing pressure causes normally dissolved gases to bubble out from bodily fluids and tissues and enter the bloodstream. This effect may occur, for example, when divers return to the surface too quickly from the higher pressure of underwater depths.
The bends is also called decompression sickness or caisson * sickness. Water pressure increases with depth. When people go scuba diving, as they dive deeper under water, the pressure of the air they breathe also increases. This increase in pressure causes more air to dissolve in the bloodstream.
Symptoms of the bends usually appear within 90 minutes of returning to ground level but may take as long as two days to appear. In minor cases, symptoms include itching, rash, joint pain, or skin discoloration. In severe cases, symptoms may include extreme pain in the joints, headache, seizures, hearing problems, nausea and vomiting, back or abdominal pain, vision disturbances, or chest pain.
Minor cases of the bends usually require no treatment, although the patient should still consult a doctor. Severe cases, by contrast, require treatment with a hyperbaric (hy-per-BARE-ik) chamber, a device that creates pressure to dissolve the gas bubbles. The patient is placed under high-pressure conditions, and the pressure is slowly and safely decreased. Prompt treatment increases the chances for a complete recovery. Unfortunately, these chambers are not available everywhere, and a person with the bends may have to be transported and possibly airlifted significant distances to receive proper treatment.
About 5 million people scuba dive. Scuba divers must be certified by taking training classes in which they learn how to dive and resurface safely to avoid decompression sickness. The bends is a preventable condition when safety rules are followed carefully.
See also Altitude Sickness
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Divers Alert Network. 6 W Colony Pl., Durham, NC 27705. Tollfree: 800-446-2671. Website: http://www.diversalertnetwork.org (accessed November 20, 2015).
* caisson (KAY-son) is a watertight container that divers or construction workers use underwater.