Even astronauts are susceptible to "bends".

• Position: Decompression Sickness - Medical research - Brief Article - Statistical Data Included

From the depths of the ocean to deep space, the same type of medical treatment given to divers for the bends may prove useful to astronauts during the construction of the international space station, says Richard E. Moon, an anesthesiologist from Duke University Medical Center, Durham, N.C. The bends, also known as gas bubble disease or decompression sickness, occurs when divers, aviators, or astronauts move too quickly from higher to lower atmospheric pressures.

Working outside the international space station in spacesuits elevates astronauts' risk of decompression sickness, Moon indicates, since the transition from the stations to a space suit rapidly lowers the pressure to which the astronaut is exposed by two-thirds. Nitrogen exhaled under pressure dissolves in the body, but when pressure decreases too rapidly, nitrogen collects in tissues faster than the body can process it. The gas accumulates in joints and blood vessels, forming bubbles that impair oxygen flow to tissues. This causes severe pain, numbness, weakness, and, in some cases, paralysis.

"Although we know of no cases of decompression sickness in space, the number of extravehicular activities (EVAs), even with the Russian program, has been fairly small," Moon points out. "Cases of decompression sickness in space could occur as the number of EVAs soar into the hundreds during construction of the space station."

Severe cases of decompression sickness can be fatal, but the illness is usually highly treatable early on. Treatment primarily consists of having the patient breathe 100% oxygen at higher than normal atmospheric pressure inside an enclosed space called a hyperbaric oxygen chamber. The oxygen...