BLOOD-OXYGEN TRANSPORT FUNCTION IN CARDIOPULMONARY BYPASS-SURGERY FORACQUIRED HEART VALVULAR DISEASES

Intraoperative analysis of the principal parameters of oxygen transpor t was carried out in 123 cardiosurgical patients before and after radi cal correction of an acquired heart valvular disease of rheumatic orig in. The study was carried out in two groups of patients operated on un der ataralgesia (n = 74) and total intravenous anesthesia (n = 49). Th e principal parameters that reflect oxygen homeostasis at various stag es of the operation are heart productivity, oxygen supply and consumpt ion. Reduced cardiac output, that most frequently develops directly be fore cardiopulmonary bypass onset, results in impairment of oxygen sup ply, To maintain metabolism under such conditions, oxygen extraction f rom the blood is increased. Analysis of correlations helped determine the critical level of oxygen supply: 350 ml/min/m(2); a lower level of oxygen supply involves reduction of oxygen consumption, formation of oxygen debt, and lactate accumulations. Limited oxygen supply is more incident in the patients operated on in conditions of ataralgesia incl uding nitrous oxide. Administration of the drugs stimulating heart pro ductivity in the early postperfusion period effectively correct disord ered oxygen transport function of the blood in the patients with reduc ed oxygen supply, whatever the anesthetic method employed. Dopamine in fusions in dose 5-7 mu g/kg/min help compensate for oxygen debt, which fact is proved by a positive time course of blood lactate levels.