Combined technique for cardiac anaesthesia

Abstract

With the recent renewed interest in early extubation after cardiac surgery, it now behooves the anaesthetist to modify the more traditional cardiac anaesthetic technique to fit this aim. However early extubation depends on an anaesthetic technique that combines both good intraoperative anaesthesia, producing haemodynamic stability, with profound postoperative analgesia. The latter is particularly important as pain is the primary cause of postoperative pulmonary complications. The idea of early extubation after cardiac surgery was first suggested in the mid 1970's when an inhalational anaesthetic technique was popular. 2 Prolonged postoperative support was then, (and still is) routine after cardiac surgery in many centres to reduce hypoxia and pulmonary complications.3 With popularization of the high dose opioid technique in the late 1970's, 4 especially with the introduction of fentanyl, 5 postoperative respiratory support became mandatory. Recently improvements in anaesthetic, surgical, monitoring and extracorporeal circulatory techniques have considerably reduced the incidence of postoperative respiratory complications.6 This has lead to a reevaluation of the need for delayed extubation. The possibility of safe and early extubation depends on the anaesthetic methods used for intraoperative anaesthesia and postoperative analgesia. Recently, much interest has been focused on a technique developed by Cheng et al. in Toronto 7 which uses short acting agents during the intraoperative course and conventional on demand analgesia postoperatively. In this issue of the Journal Kowalenski et al. s describe a technique of general anaesthesia supplemented with subarachnoid bupivacaine and morphine in 18 patients undergoing coronary artery bypass surgery. The aims of this innovative technique were to provide a stable intraoperative haemodynamic course, to decrease requirements for long-acting opioids and, potentially, to obtain the beneficial effects of cardiac sympatheetomy. After general anaesthesia with alfentanil 97 -t22 I~g kg-J and midazolam 0.04 -I0.02 ragkg -I, subarachnoid anaesthesia (SA) with hyperbaric bupivacaine 23-30 mg (15 patients), lidocaine 150 mg (1 patient)