LOW-DOSE SUFENTANIL-ISOFLURANE ANAESTHESIA FOR CORONARY ARTERY SURGERY

Haemodynamic changes and catecholamine responses were measured during anaesthesia with sufentanil (total dose 7 μg kg−1) supplemented with isoflurane in 14 patients undergoing coronary artery surgery. Isoflurane was used to control systolic arterial pressure, which was allowed to decrease to 100 mm Hg. Mean inspired isoflurane concentration was 0.22 (SD 0. 19)% (induction), 0.34 (0.18) % (prebypass) and 0.22 (0.17)% (post-bypass). During cardiopulmonary bypass 0.22 (0.13) % isoflurane was administered to control mean perfusion pressure. During induction and the pre-bypass period, significant decreases in systolic and diastolic arterial pressure, systemic vascular resistance and left ventricular stroke work index (LVSWI) (P< 0.01) were noted. The decrease in LVSWI with unchanged filling pressures indicated myocardial depression. Serum catecholamine concentrations remained at the pre-induction value until cardiopulmonary bypass. when a significant increase was noted. Tracheal intubation, sternotomy and sternal spread were not associated with hypertension or tachycardia. Clinical signs that could reflect myocardial ischaemia were not observed per-operatively. After operation, cardiac enzymes were within the normal clinical range and ECG was unchanged.