HEMODYNAMIC-EFFECTS OF ANESTHETIC INDUCTI ON WITH 3 DIFFERENT DOSAGESOF ELTANOLONE IN CORONARY-ARTERY BYPASS PATIENTS

Eltanolone is a new steroid anaesthetic agent that is a 5-beta reduced derivative of progesterone. In the present study we investigated the haemodynamic effects of eltanolone or thiopentone in patients schedule d for coronary artery bypass grafting. Methods. After obtaining approv al of the institutional ethics committee and informed patient consent, 40 patients (age 45-70 years, ASA III and IV, ejection fraction >50%, cardiac index >2.5 1/min per m(2)) were randomly assigned to four gro ups, each containing 10 patients: After premedication with 2 mg flunit razepam, anaesthesia was induced with 3 mg/kg thiopentone in group 1, 0.5 mg/kg eltanolone in group 2, 0.75 mg/kg eltanolone in group 3, 1.0 mg/kg eltanolone in group 4. Each patient additionally received 3 mu g/kg fentanyl after induction and 0.1 mg/kg pancuronium. Heart rate, m ean arterial pressure, pulmonary arterial pressure, central venous pre ssure, pulmonary artery occlusion pressure and cardiac output were rec orded in the awake state, 2 ruin after induction of anaesthesia, and 1 and 5 min after intubation. Cardiac index and systemic vascular resis tance were calculated. Results. Two minutes after induction, mean arte rial pressure was significantly lower than the baseline (P<0.05) in ea ch group, Mean arterial pressure changes were more prominent in the ca se of eltanolone, but intergroup tests did not reveal significant diff erences between the four groups. There was a fall in cardiac index in all groups, and these changes reached the level of significance only i n the thiopentone patients. The most obvious difference between eltano lone and thiopentone was systemic vascular resistance. It dropped sign ificantly 2 min after induction with eltanolone at all dosages. In con trast, there was an increase in systemic vascular resistance following induction of anaesthesia with thiopentone. Intergroup tests also show ed significantly (P<0.05) lower systemic vascular resistance 1 and 5 m in after intubation with eltanolone compared to thiopentone. Discussio n. Mean arterial pressure reduction induced by eltanolone is most like ly the result of the combination of a decrease in cardiac contractilit y and peripheral vasodilatation. In contrast, mean arterial pressure r eduction in the case of thiopentone seems to be exclusively related to the negative inotropic properties of the drug, Results Of a dosage fi nding study [5] with eltanolone revealed an AD(50) of 0.33 mg/kg. In o ur study 0.5 mg/kg eltanolone brought all the patients to sleep within 2 minutes, The haemodynamic results do not show any significant diffe rence up to twofold dosage, Therefore, the therapeutic margin seems to be large. Because of considerable interindividual variability additio nal studies larger collectives are required for definitive evaluation of the drug.