A Randomised Clinical Study on Haemodynamic Effects of Thiopentone and Etomidate as Induction Agents in General Anaesthesia

Introduction: Thiopentone and Etomidate like anaesthetic agents are often used for induction during anaesthesia. Induction is the preliminary step in general anaesthesia and the search for a perfect agent is a persistent quest for the anaesthetist.

Aim: To compare the haemodynamics status and safety profile of thiopentone and etomidate as induction agent.

Materials and Methods: The present randomised clinical trial was conducted on 120 patients, of either sex between 18-45 years of age belonging to American Society of Anesthesiology (ASA) grade I and II. They were divided into two groups with 60 patients in each. Group T patients were induced with injection (inj.) thiopentone 5 mg/kg and group E patients were induced with inj. etomidate 0.3 mg/kg as an induction agent. Vital parameters like heart rate, non invasive blood pressure of all patients were recorded at baseline (before induction), after induction and post intubation at an interval of 1, 3 and 5 minutes. Adverse effects during intraoperative period were noted and later analysed. Quantitative data were analysed using Unpaired t-test to assess the changes within group.

Results: Out of 120 study participants, 70 were males and 50 females with the mean age of 35.63±12.20 and 34.50±7.46 in group T and group E respectively. The induction time in the Group E (27.5±3.31 seconds) was significantly less (p<0.05) as compared to group T (31.71±4.8 seconds). Change in heart rate was lesser (p<0.05). There were no significant changes in the respiratory rate in either at any stage of anaesthesia. Adverse effects like apnoea were evident more in the group T patients whereas pain at injection site and myoclonus was more evident in the group E patients. But, the overall safety profile of etomidate was better than thiopentone.

Conclusion: Etomidate found to be more effective, rapid acting induction anaesthetic agent with good cardiovascular stability and respiratory stability with least incidences of apnoea as compared to thiopentone.