TOTAL INTRAVENOUS ANESTHESIA WITH GAMMA-HYDROXYBUTYRATE (GHB) AND SUFENTANIL IN PATIENTS UNDERGOING CORONARY-ARTERY BYPASS GRAFT-SURGERY - A COMPARISON IN PATIENTS WITH UNIMPAIRED AND IMPAIRED LEFT-VENTRICULARFUNCTION

The haemodynamic effects of anaesthesia with gamma-hydroxybutyrate (GH B)/sufentanil for elective coronary artery bypass grafting (CABG) were investigated and compared in patients with unimpaired left ventricula r function (ejection fraction greater than or equal to 45%, left ventr icular end diastolic pressure less than or equal to 16 mmHg) and patie nts with impaired left ventricular function. In 38 consecutive patient s scheduled for CABG (21 with unimpaired and 17 with impaired left ven tricular function), anaesthesia was induced with etomidate, sufentanil and pancuronium. After tracheal intubation, the lungs were normoventi lated tend tidal PCO2 4.9-5.6 kPa) with an oxygen-air mixture (FIO2 0. 5). Total intravenous anaesthesia was maintained with GHB (20 mg kg(-1 ) h(-1) after a 'priming dose' of 40 mg kg(-1)) and sufentanil (2 mu g kg(-1) h(-1)). Haemodynamic measurements were made after induction of anaesthesia and at various times in the prebypass period. Patients in both groups showed similar haemodynamic trends. Mean arterial pressur e showed a maximum reduction of 10%, whereas heart rate and right- and left-sided filling pressures remained unchanged within the groups aft er the induction of anaesthesia. Cardiac index remained unchanged in b oth groups, although values differed between the groups. A total of 14 out of 21 patients (67%) with unimpaired and 10 out of 17 patients (5 9%) with impaired ventricular function required supplementary administ ration of opioids to control temporary hypertension after sternotomy. No episodes of myocardial ischaemia were detected during the study per iod using ST segment analysis (leads II and V-5). The results of this study suggest that GHB provides adequate haemodynamic conditions in th e prebypass period and may be a suitable agent for TIVA also in patien ts with impaired left ventricular function undergoing CABG.