[Components of anesthesiological provision and central hemodynamics in hypothermia without perfusion]

Central hemodynamics was studied by thermodilution in 16 patients with acquired mitral defect during surgery under conditions of hypothermia without perfusion. Cooling and surgical correction were carried out under superficial ether anesthesia with morphine and droperidol. A 28% decrease of the minute circulation volume is observed as early as under general anesthesia and at the very beginning of cooling (10.8% more); this decrease is caused by rarer heart contractions and increase of the total peripheral vascular resistance as a result of body response to cool exposure. An almost 10 degrees C drop of body temperature (to 27.2 +/- 0.2 degrees C) involves a just 13% decrease of the cardiac index in comparison with the value at the beginning of cooling. Injection of droperidol before cooling blocks the increase of the total peripheral resistance in a dose-dependent mode (about 0.13 mg/kg of droperidol is needed for sufficiently complete prevention of the increase of total peripheral resistance), and thus maintains the stroke and cardiac indexes at a sufficiently high level. Morphine (in doses of up to 2.3 mg/kg) did not bring about such an effect.