A randomised controlled trial to study Bispectral guided induction of general anaesthesia using propofol and...

The present prospective, randomised study was done to evaluate induction characteristics with bispectral (BIS) index guided infusion of propofol and etomidate.

After institutional ethical committee approval, 70 patients, aged 18-60 years, American Society of Anaesthesiologists (ASA) I and II scheduled for elective surgery were included. Patients were randomly allocated into one of the two groups. In Group E, patients received etomidate infusion at a rate of 0.07 mg kg^-1 min^-1 and in Group P, received propofol infusion of 0.7 mg kg^-1 min^-1. Time from start of infusion to loss of palpebral reflex (T_P), loss of verbal command (T_V), BIS to reach 50 (T_BIS50), mean induction dose and incremental dose of each drug required to keep BIS_50., haemodynamic parameters and adverse effects like pain, myoclonus, apnoea and postoperative nausea and vomiting (PONV) were also noted.

T_P,T_V, and T_{BIS 50} was faster in E as compared to P group and was statistically significant for all parameters. Mean induction dose of drug required till BIS 50 was 2.68 ± 0.56 mg kg^-1 and 0.242 ± 0.11 mg kg^-1 in group P and E, respectively. There was a significant difference between the groups with group E requiring incremental dose in a significant proportion of patients (P = 0.004). There was a significant decrease in MAP in P group as compared to E. In group P, more number of patients experienced pain and had apnoea episode as compared to group E. (P < 0.001). Myoclonus was observed in group E only (P = 0.016).

BIS-guided titration of propofol and etomidate infusion for induction did not result in reduction of the dose, haemodynamic variations and other effects.