[Oxygen transport function of blood in open heart surgery]

Complex intraoperative analysis of oxygen transporting function was performed in two groups of cardiosurgical patients operated on under ataralgesia (74 patients) and total intravenous anesthesia (49 patients). Heart performance, oxygen delivery (DO2) and O2 consumption (VO2) were the basic parameters reflecting O2 homeostasis at all stages of surgery. A decline in the cardiac output which is most frequent immediately before the beginning of cardiopulmonary bypass procedure leads to the disturbances in DO2. Metabolism maintenance in these conditions is due to increased O2 extraction from blood. According to the data of correlation analysis, a critical DO2 level, below which a decline of VO2, O2 debt and lactate accumulation are observed, is 350 ml/min/m2. Limited DO2 is more frequently encountered in patients operated on under ataralgesia using nitrous oxide. The use of drugs improving heart performance in the early postperfusion period is an effective technique of CPK damage correction in patients with decreased DO2, irrespective of the anesthesia technique. Dopamine administration at a dose of 5-7 micrograms/kg/min makes up for O2 debt, which is confirmed by positive changes in blood lactate.