A Randomised Control Trial on the Effects of Fentanyl vs Subanaesthetic Dose of Ketamine given along with Propofol on Anaesthetic Profile and Recovery Characteristics

Abstract

Introduction: Total Intravenous Anaesthesia (TIVA) has been a subject of interest for all anaesthesiologists. TIVA was initially attempted with a single drug but no drug was found to give complete anaesthesia. So, the technique of co-induction using two or more agents to induce anaesthesia has been studied. With the invention of newer induction agents, opioids and amnestic agents having shorter half-life, with advents of infusion pumps and depth of anaesthesia monitors like Bispectral Index (BIS), TIVA is gaining popularity day by day. Aim: To compare the effects of fentanyl or subanaesthetic dose of ketamine given along with propofol in TIVA. Materials and Methods: A randomised double blind study was conducted in patients who underwent elective laparotomy under TIVA. Sixty-two ASA grade I and II patients were randomised to receive either subanaesthetic dose of ketamine or fentanyl along with propofol for induction. Infusion of one of the study drugs was continued during maintenance along with propofol infusion which was titrated to maintain BIS of 40-60. Vecuronium was used to provide muscle relaxation and bolus doses of fentanyl were given whenever additional analgesia was needed. Intraoperative propofol, vecuronium and additional fentanyl requirement, time for tracheal extubation and time for first postoperative analgesic request were recorded. Continuous data was analysed with Student’s t-test and categorical data was analysed with Chi-square test. A p-value less than 0.05 were considered statistically significant. Results: Immediately after induction, haemodynamics were more stable in the ketamine group when compared to the fentanyl group. There was also a significant decrease in propofol requirement (6.501±0.24 Vs 6.672±0.26 mg/kg/hr) and a delay in the request for first postoperative analgesia in ketamine group (57.50±38.20 vs 40.50±22.68 minutes). Conclusion: Pre-incisional bolus of subanaesthetic ketamine followed by an infusion intraoperatively maintains haemodynamic stability, provides analgesia, decreases propofol requirement and delays request for first postoperative analgesia.