Comparative evaluation of bispectral index and hemodynamic changes during induction of anaesthesia with propofol and thiopentone

Abstract

Background: Induction requires sufficient anaesthetic depth to prevent patient awareness while maintaining hemodynamic stability. The research study used Bispectral index (BIS) measurements to test the effectiveness of thiopentone and propofol as general anaesthesia induction agents.

Methods: A randomised prospective trial with masked members of the study overcame the logistical issues of recruiting 60 ASA I patients of between18-65 years of age for consecutive first time surgical procedures, with all patients recruited on a non first case basis. The 60 patients were placed randomly into two groups for receiving either thiopentone 5 mg/kg (Group T) or propofol 2 mg/kg (Group P) as their induction agents. The study was conducted for 600 seconds with the first data collection point being at the start of the procedure (0) and at 24 seconds after induction, including BIS measurements along with heart rates and mean arterial pressure.

Results: BIS values were found to decrease following propofol use by a total of 33.7±7.43 while thiopentone was 44.8±10.61. The total duration of a BIS<60 was greater for propofol than thiopentone (190.13±91.0 seconds versus 70.53±41.3 seconds). At 240 seconds post administration, propofol BIS was 43.9±15.12 and thiopentone was 65±6.8. It was also determined that thiopentone provided better hemodynamic stability since it caused very little decrease in mean arterial pressure or heart rate.

Conclusions: Propofol was better than thiopentone in preserving sufficient hypnotic depth during induction and intubation, but thiopentone had better hemodynamic stability.