Abstract No.: ABS0888: BIS (Bispectral Index) The current tool for monitoring of unintended awareness and depth of anaesthesia

Abstract

Background & Aims:

Awareness under general anaesthesia is an unpleasant phenomenon which often goes unnoticed and neglected. Numerous incidences of intraoperative awareness are not reported. Our aim was to evaluate intraoperative awareness during general anaesthesia and titrate amount of anaesthetic agents according toBispectral Index ( BIS).

Methods:

This randomised, prospective comparative study was conducted in 100 adult patients, randomly divided equally in to 2 groups: BIS and NON BIS. After obtaining written informed consent,patients belonging to American Society of Anesthesiologists (ASA) grade 1and 2, aged 20-60 years, weighing 40-75 kg posted for elective surgical procedures in various specialties under general anaesthesia were included. Patients with ASA 3 & 4, psychiatric illness on medication, language barrier, pregnancy or known allergy to propofol were excluded. Postoperatively intraoperative awareness was assessed by modified form of Brice questionnaire at various time intervals. Hemodynamic parameters were monitored and total propofol consumption was calculated.

Results:

Intra-operative awareness reported was 2% in BIS group and 8% in NON-BIS group. Total propofol consumption in BIS group was significantly less as compared to NON BIS group respectively 8.25±1.7 mg vs 11.15±2.5 mg (P value <0.0001).

Timepoint Comparison	Change in RBS (mg/dL) from Baseline to Follow-up Timepoints				P for Comparison of the two Groups in Terms of Difference of RBS (mg/dL) from Baseline to Follow-up Timepoints
	Group: Sevoflurane		Group: Desflurane
	Mean (SD) of Absolute Change	P of Change Within Group	Mean (SD) of Absolute Change	P of Change Within Group
Post-Induction - Baseline	4.97 (2.38)	<0.001	0.03 (0.71)	1.000	<0.001
1 H - Baseline	5.26 (3.63)	<0.001	1.00 (0.80)	0.558	<0.001
2 H - Baseline	4.74 (3.02)	<0.001	1.94 (1.19)	0.003	<0.001
3 H - Baseline	4.15 (2.89)	<0.001	2.77 (1.33)	<0.001	0.011
4 H - Baseline	4.67 (2.34)	<0.001	3.03 (1.42)	<0.001	0.002
5 H - Baseline	5.48 (3.15)	<0.001	3.09 (1.47)	<0.001	0.001
6 H - Baseline	6.10 (3.57)	<0.001	2.46 (1.37)	<0.001	<0.001
7 H - Baseline	5.32 (3.06)	<0.001	2.61 (1.85)	<0.001	0.004
8 H - Baseline	4.81 (2.79)	<0.001	1.50 (2.07)	<0.001	0.008
9 H - Baseline	7.27 (3.88)	<0.001	4.50 (0.71)	<0.001	0.260

Conclusion:

BIS serves as an excellent tool for awareness monitoring and titration of anaesthetic drugs perioperatively

PROPOFOL consumption
Dose	Group BIS	Group non-BIS	P
I Induction (mg/kg)	1.75±0.15	2.15±0.15	<0.0001
Maintainence (mg/kg/h)	5.50±1.5	9.0±1.8	<0.0001
Total	8.25±1.7	11.15±2.5	<0.0001

Data expressed as mean±SD

AWARENESS IN BOTH GROUPS.