Reduction of postischemic edema with hyperbaric oxygen.

In recent years, reports have shown positive effects of hyperbaric oxygen (HBO) treatment in posttraumatic circulatory insufficiency of the extremities. A tourniquet model for temporary ischemia was used to examine such treatment in rats. The circulation of the rat hindlimb was interrupted for 3 hours, while the contralateral uninjured leg served as control. There was a significant (p less than 0.001) postischemic edema in the tourniquet leg up to 48 hours after restoration of circulation. One group of animals received treatment with hyperbaric oxygen at 2.5 atmospheres absolute (ATA) for 45 minutes after release of the tourniquet. This significantly reduced (p less than 0.001) the postischemic edema, and the reduction persisted for 40 hours after the last treatment. It is concluded that hyperbaric oxygen reduces postischemic edema. Hyperbaric oxygen may therefore be useful as an adjuvant in the treatment of acute ischemic conditions when surgical repair alone fails or is not sufficient to reverse the ischemic process.