Introduction: Entropy of electroencephalogram (EEG) quantifies the degree of chaos, complexity or irregularity of the EEG signal. The EEG activity would show more regularity in anaesthetized, than in awake patients. In recent years, Propofol is used commonly as an intravenous induction agent during General Anaesthesia as the recovery is smooth and clear. Aims: To Study the effect of spectral entropy on the requirement of Propofol during induction of Anaesthesia.

Materials and Methods: 40 patients belonging to ASA grade 1 and ASA grade 2 undergoing spine surgeries under general anaesthesia were taken in the age group of 20 years to 60 years and randomly allocated to 2 groups after taking approval from institutional ethics committee.

Results: The demographic profile (age, age wise distribution, gender wise distribution, weight, weight wise distribution, height, height wise distribution) was comparable in both the groups. Haemodynamic parameters (heart rate, systolic, diastolic blood pressure and entropy parameters) were comparable in both the groups. The amount of propofol per kg dose decreased from 2mg/kg to 1.4mg/kg when induction was done using the entropy sensor. This decrease in the dose was statistically significant with p<0.05. This decrease in the total dosage was 25.3% and 27.8% with respect to the total dose and per kg dose of propofol respectively. The end result showed that inclusion of entropy monitor during general anaesthesia for induction with propofol decreased the requirement of propofol for induction when compared with propofol requirement without entropy monitoring. This decrease in propofol requirement was statistically significant. However the hemodynamic stability was not significantly different in both the groups.

Conclusion: Propofol, an intravenous induction drugwhile monitoring the depth of anaesthesia with spectral entropy, the requirement of propofol during induction of anaesthesia is significantly reduced in comparision when induction of anaesthesia was done without spectral entropy monitoring