Comparison between Haemodynamic Responses of Propofol Induction between BIS Guided Dose and Sleep Dose: A Randomised Control Trial

Abstract

Introduction: Propofol contributes largely in the rapid evolution of day care surgery due to its superior recovery characteristics. However, it is associated with dose-dependent systemic arterial hypotension which increases morbidity and mortality. Bispectral index or BIS is an Electroencephalographic (EEG) derived parameter used to assess the depth of anaesthesia. Titrating drugs to a specific BIS value during general anaesthesia allows to adjust the dose of anaesthetic needed by the patient thereby, reducing the dose related side-effects. Aim: To determine whether the dose of propofol guided BIS values causes less arterial hypotension than the commonly used sleep dose method. Materials and Methods: The present study was a randomised control trail conducted on 92 patients of American Society of Anesthesiologists (ASA) I and II physical status, aged 18-60 years, of both genders, scheduled for elective surgeries under general anaesthesia and were randomly divided into group A and B (46 in each). For induction of anaesthesia, Group A received propofol till the BIS values reached 50±1 for 30 seconds, while Group B received sleep dose of propofol without BIS monitoring. Haemodynamic effects Heart Rate (HR), Diastolic Blood Pressure (DBP), Systolic Blood Pressure (SBP) and Mean Arterial Pressure (MAP) were recorded at baseline, during induction and at 1, 5, 10 and 15 minutes after intubation. Total propofol consumption and secondarily, level of sedation after extubation using Ramsay Sedation Scale were also measured in both the groups. Results: The total dose requirement of propofol was reduced significantly in group A compared to group B (p<0.005). Blood pressure decreased from the baseline in both the groups following induction with propofol but was insignificant. HR increased by 2.2% in group A while it decreased by 8.5% in group B but was insignificant (p>0.005). On arrival to Post Anesthesia Care Unit (PACU), group A were more co-operative, oriented patients compared to group B (67.4% vs 32.6% respectively). Conclusion: BIS monitoring significantly reduces the consumption of propofol for induction of anaesthesia while the incidence of hypotension was similar in both the groups. Lower sedation level with comparatively better extubation score with the use of BIS helps in fast tracking.