[Temperature regimen of extracorporeal circulation during aortocoronary bypass surgery]

The purpose of the study is to comparatively evaluate the impact of normo- and hypothermic perfusion on acid-base balance (ABB), gas blood composition, metabolic parameters, and hemostasis. Fifty patients undergone multiple aortocoronary bypass under extracorporeal circulation (EC) were examined. Twenty four patients and 26 (Groups 1 and 2, respectively) had been operated on under normo- and hypothermia. The groups did not differ in age, body weight, the duration of an operation, the number of shunts, the time of EC, and myocardial ischemia. ABB, gas blood composition, the concentrations of hemoglobin, lactate, fibrinogen, prothrombin time, thrombin time, activated partial thromboplastin time, activated coagulation time, blood coagulation time as described by Leigh-White, the count of platelets, and ADP-induced platelet aggregation in the early postperfusion and postoperative periods, following 24 and 48 hours after surgery. There were no significant differences in the values of ABB, gas blood composition, blood lactate levels in patients from both groups. However, metabolic acidosis, elevated blood lactate concentrations were more frequently encountered in Group 2 patients, which suggests that hypothermia prduces a more aggressive effect on systemic homeostasis. Impact of normo- and hypothermia on the coagulative link of homeostasis was not revealed. Nevertheless, hypothermic EC halved the functional activity of platelets, which has a substantial effect on the size of postoperative blood loss.