Comparison of volatile agent isoflurane vs conventional methods with intermittent propofol and benzodiazepine for BIS targeted anaesthesia on cardiopulmonary bypass

Abstract

Incidence of awareness in patients undergoing cardiac surgery is up to 23% compared to its incidence of 1% during general surgery. In our institute we conducted study in 40 patients undergoing valve surgeries and compared volatile agent vs. conventional method with help of BIS monitoring. Partly because of the difficulty of administering volatile agents during cardiopulmonary bypass (CPB), total intravenous anaesthesia (TIVA) has been a popular technique used by cardiac anaesthetists in the last few decades. However, the possibility that volatile agents cut back mortality and the incidence of myocardial infarction by preconditioning the myocardium has stimulated a revival of interest in their use for cardiac anaesthesia. We observed the higher BIS values were seen in conventional group with requirement of higher dose of propofol as a rescue to avoid intraoperative awareness. The haemodynamics were steadily maintained in isoflurane group. The inotrope score was less in isoflurane group indicating myocardial protective effect of isoflurane. In conclusion, in patients undergoing heart surgery with CPB, the findings of this study indicate that appropriate use of isoflurane to maintained depth of anaesthesia during CPB should be monitored with use of BIS and ETAC.