Remifentanil and alfentanil. Sympatho-adrenergic effects during the early postoperative period in patients with cardiac risk

Extubation and the immediate postoperative period are critical periods with strong sympatho-adrenergic stimulation. The aim of the present study was t o investigate this period after balanced anaesthesia with remifentanil and alfentanil in cardiac risk patients. Methods: 52 patients with coronary artery disease or with risk factors for coronary heart disease scheduled for elective extraperitoneal and extrathor acic operation were included in this study. Anaesthesia was induced by intr avenous administration of etomidate, vecuronium and remifentanil (n=27, 1 m u g/kg) or alfentanil (n=25, 25 mu g/kg). Anaesthesia was maintained with a n Isoflurane/N2O/O-2 mixture and by continuous intravenous infusion of remi fentanil (0,25 mu g/kg/min) or alfentanil (45 mu g/kg/h). During the first 60 minutes after extubation haemodynamic parameters were monitored and cate cholamines were determined at defined time intervals. Parameters of recover y, the requirement of analgesics and cardiac medications were compared in b oth groups. Myocardial ischaemia was assessed by two-channel Holt electroca rdiography. Results: The beginning of spontaneous respiration and time of extubation we re similar in both groups. The time interval until opening eyes and the lim e between the beginning of spontaneous respiration and extubation was short er in the patients treat ed with remifentanil. In this group patients suffe red earlier from pain and had a higher pain score. Although the plasma cate cholamines were comparable in both groups,in the patients treated with remi fentanil changes in haemodynamic parameters were more pronounced. The incid ence of shivering and the requirements of analgesics and cardiac medication s were higher in these patients. The incidence of ST-segment changes indica ting myocardial ischaemia was similar. Conclusions: After balanced anaesthesia with remifentanil a more pronounced sympatho-adrenergic stimulation occurs because of the more rapid clearance of the analgesic effect in the recovery period compared to alfentanil requ iring more analgesics and medications for the control of the haemodynamic p arameters. Because of these specific pharmacological effects the use of rem ifentanil in cardiac risk patients has to be critically discussed.