The Effect of BIS Usage on Anaesthetic Agents Consumption in High-risk Patients for Coronary Artery-bypass Grafting Off-pump Surgery

Abstract

This study aimed to compare whether Bispectral Index (BIS) reduces the consumption of the anaesthetic drug and improves recovery time in coronary artery-bypass grafting off-pump (CABG-OP) surgery without awareness during surgery (ADS). The study was a single centre, prospective, randomised, and double-blind comparative research on ASA 3 patients booked for elective CABG-OP operation under general anaesthesia (GA). Patients received either propofol or isoflurane anaesthesia, and their consumption was calculated and compared. The conventional groups CPG-1 and CIG-3 received propofol and isoflurane, and haemodynamic parameters (± 20% of initial values) were considered for anaesthesia. The groups BPG-2 and BIG-4 received propofol and isoflurane, and BIS (value 50±5) was used to maintain anaesthesia. In addition, haemodynamic parameters, awakening conditions, length of intubation, hospital stay and drug utilisation were recorded. To explicit ADS, patients were interviewed 24 hours after extubation. The quantity of propofol used was 178 ± 11 ml in CPG-1 and 117 ± 6 ml in BPG-2, with a 34.26% reduction with BIS. The isoflurane used was 39 ± 8 ml in CIG-3 and 25± 6ml in BIG-4, with a 35.89% reduction in isoflurane requirement. This difference was statistically significantly low with BIS monitored anaesthesia compared to conventional anaesthesia. The length of intubation was 2.2 ±1.27 and 2.3 ±1.49 hours in groups BPG-2 and BIG-4, respectively (p<0.05). BIS assisted CABG-OP surgeries with adequate depth of anaesthesia (BIS 50 ± 5) prevent ADS, reduce the anaesthetic agent requirement, and aid ultra‐fast‐track (UFT) extubation.