Comparative study of entropy module and titrated doses of propofol for induction of anaesthesia

Background: Propofol leads to dose related reduction in blood pressure. The rationale of this study was to estimate the dose of propofol required & haemodynamic stability by use of spectral entropy during induction of general anaesthesia. Method: It is an observational study including 170 participants aged 18 years & above with ASA 1 and 2 physical status undergoing elective surgery under general anaesthesia. Participants were divided into 2 groups. 1): subjects assigned to Entropy guided (target range 40-60) administration of propofol for general anesthesia induction & 2): subjects given propofol by weight (2mg/kg). The propofol induction dose, haemodynamic variables and entropy values were recorded. Numerical data were expressed as a mean ± standard deviation and analyzed using t-test & Anova p test. P value less than 0.05 was considered significant. Results: The mean change in MAP after 2 mins was calculated and given as 8.91± 4.08 in Entropy group and 11.66 ± 6.82 in Non-Entropy group and p value was found 0.002 which was highly significant. Mean of Propofol given as per conventional technique (2mg/kg) was 107.06 ± 26.041and given as per Entropy was 78.00 ± 22.028 & p values using t test was 0.000 (highly significant). Conclusion: Requirement of Propofol for GA induction when given based on loss of verbal response was significantly higher than the guided by EEG entropy.