Abstract

The changes in pulmonary compliance have been studied under conditions of total body hypothermia. Five groups of sheep were used; two groups were controls—one for the effects of anaesthesia and the other for normothermic biventricular bypass. The third group was cooled using a femoro-femoral arterio-venous shunt to 20°-23° C. The fourth group was cooled to 15° C. and rewarmed using the Drew technique. The excised lungs of the remaining sheep were studied at 37° and 15° C. (fifth group). The controls showed little change in compliance. The cooled animals showed a decrease in compliance. In the group subjected to hypothermia by the Drew technique, the rewarming phase initially brought a return towards normal compliance. As the temperature rose to 24°-30° C. the improvement in compliance ceased and thereafter compliance decreased for two hours after rewarming. Histologically the lungs were normal. There was no compliance change caused by cooling the excised lungs.