Tissue changes at different periods of ischemia.

A multidisciplinary study was done to examine the following: (a) pathophysiological changes in muscle and nerve response following different periods of normothermic and cold ischemia; (b) alterations in the release of enzymes (K, LDH), CA++, K=and lactate under these conditions; and (c) histological alterations of vessels, nerves and muscles after different periods of normothermic and cold ischemia. The results demonstrate that hypothermic ischemia greatly reduces both the leakage of enzymes, cellular damage and pathological responses. We infer that amputated parts containing muscular masses may be replanted with good prognosis for satisfactory functional results within 4-5 hours at room temperature. By reducing the temperature, the time between cooling and revascularization may be doubled. Parts without muscles may be replanted 10-12 hours after normothermic ischemia and up to 24 hours or even longer after cold ischemia.