Volatile anesthetic consumption by bispectral index monitoring compared to hemodynamic monitoring

Abstract

Bispectral index (BIS) is a method for monitoring depth of anesthesia by using electroencephalogram (EEG) analysis. BIS value of 40-60 can reduce the incidence of awareness  during general anesthesia. Another advantage of BIS is facilitating adjustment of anesthetic requirement in each patient which will lead to reduction of emergence time, recovery time and  postanesthetic complications. The objectives of this study are comparison of consumption of volatile anesthetic agents, emergence, and recovery time including postanesthetic complications  within 24 hours between the patients that are monitored by BIS and hemodynamics during general anesthesia. The method of data collection was in prospective randomized controlled trial of 60 healthy patients (ASA I), age between 18-60 years old under general anesthesia for elective  surgery. The patients were randomly divided into 2 groups; group B (BIS group) was monitored by BIS and group H (hemodynamic group) monitored by hemodynamic responses. All patients were ventilated with autoflow mode of Draeger® Zeus anesthesia machine.The statistical analysis showed the oxygen consumption in hemodynamic group was lower than BIS group with statistical  significance (p=0.03). The result showed no differences in isoflurane and nitrous oxide consumption, emergence time, recovery time and postanesthetic complications between both groups. No intraoperative awareness was observed.This study concluded that monitoring depth  of anesthesia by BIS did not reduce the consumption of volatile anesthetic agents compared to hemodynamic monitoring.