The Bends

What Is "The Bends"?

The Bends, also known as decompression sickness or DCS, is caused by nitrogen bubbles forming in the bloodstream and tissues of the body. When a diver is breathing air underwater, the extra pressure causes nitrogen to dissolve into the bloodstream; when the diver ascends, the decrease in pressure can cause the dissolved nitrogen to come out of solution as bubbles of gas. DCS most classically affects divers who ascend to the surface too quickly, although decompression sickness can also happen when a pressurized aircraft loses pressure, or when someone exits a pressurized environment like a caisson or a mine.

The symptoms of decompression sickness vary because the nitrogen bubbles can form in different parts of the body. The person may complain of headache or vertigo, unusual tiredness or fatigue. He or she may have a rash, pain in one or more joints, tingling in the arms or legs, muscular weakness or paralysis. Less often, breathing difficulties, shock, unconsciousness or death may be seen.

Mild forms of decompression sickness can resolve themselves without treatment or by breathing 100 per cent oxygen at the site of the accident. But if there's any suspicion of decompression sickness, the person must be examined by a doctor. This is because, although it might not seem serious at the time, the condition may deteriorate. If the diver receives treatment at an early stage, the chances of avoiding permanent injury are good. The longer that treatment is delayed, the greater the risk of serious consequences. If you are a diver, you should take a rest from diving after treatment for decompression sickness. The length of this rest depends on the severity of the decompression sickness and the effects of treatment, and they should be discussed with a specialist in divers' medicine. To prevent decompression sickness after diving, you must get into a decompression chamber as soon as possible.

Decompression Chamber
A decompression chamber is a steel tank that can be pressurised. The pressure in a decompression chamber can be increased by closing the doors and pumping air in. During treatment for decompression sickness, pressure is increased to correspond to the pressure found 18m under water. In some cases, the pressure in the chamber is set at 50 metres. The diver breathes pure oxygen through a mask, which improves exhalation of nitrogen. At depths in excess of 18 metres, and also after adequate intervals, the mask can be removed in the chamber. Pressure in the chamber is reduced gradually until the diver reaches surface pressure again. Treatment typically lasts between five and six hours. Throughout treatment a specially trained helper stays with the diver in the chamber. The diver's condition is closely monitored by further examination of coordination and balance, sense of touch, etc. If necessary, the diver's medical specialist can join the diver in the chamber, but otherwise takes charge of the treatment outside the chamber in co-operation with the specially trained helper. After treatment, the person will be kept for 24 hours for observation in case his condition deteriorates. In most instances one course of treatment is adequate, but occasionally several treatments may be needed.

External and Interior View of a Decompression Chamber

By: Jacob Newbery