The treatment of decompression sickness.

The initial event in decompression sickness is the separation of gas from solution because of supersaturation. If this event gives rise to immediate symptoms, recompression is remarkably effective. This end-point is characteristic of joint pain, that is, Type 1 decompression sickness. Unfortunately the onset of serious Type 2 decompression sickness may be insidious and the delay may be associated with blood-brain barrier dysfunction. Pressure is less effective in the resolution of this problem than a raised partial pressure of oxygen. Standard therapy using oxygen may be associated with worsening of symptoms and air tables with recurrence. Recompression to 4 ata and the use of a mixture of 50% oxygen and 50% helium offers a good working compromise in the treatment of both serious decompression sickness and gas embolism arising in air diving, avoiding the need for a differential diagnosis. Only oxygen or helium and oxygen mixtures should be used in the therapy of decompression sickness in helium and oxygen diving. When therapy has been delayed, intravenous fluids and steroids are important adjuncts.