Pathophysiology and treatment of decompression sickness and gas embolism.

Decompression sickness and cerebral gas embolism can present as dramatic and profound sudden onset injuries in patients engaged in tunnel work and compressed gas diving, including scuba. The history and management of these illnesses span centuries. The pathophysiology relates to occurrence of gas bubbles in extrapulmonic sites. Decompression sickness is due to supersaturation of the tissue with dissolved gas and subsequent evolution of gas bubbles. Gas embolism results from the direct transit of molecular gas from a pulmonary or intravascular origin into the arterial circulation causing occlusion of a distal locus. Treatment relates to increasing hydrostatic pressure, thus maximizing the gradient for gas reabsorption and dissolution and subsequently gas excretion via the lungs.