Article type
Year
Abstract
Background: Bispectral index (BIS) is a value derived from a complex mathematical process to determine the harmonic and phase relations among the various electroencephalogram frequencies. It might improve the anaesthetic delivery and postoperative recovery by enabling titration of the dose of anaesthetics to achieve the hypnotic component of anesthesia. There are still conflicting opinions regarding the routine use of this device in anaesthesia practice. Therefore, an evaluation of the BIS monitor during anaesthesia management is useful.
Objectives: This review focuses on whether BIS incorporated into the standard practice of anaesthesia management can reduce the anaesthetic consumption, recovery time, incidence of recall awareness during operation and the total cost of anaesthesia management.
Search strategy: Published studies were searched from the MEDLINE (1966 to 2003), EMBASE (1966 to 2003) , the Conchrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library, issue 2, 2003 ) and the reference lists of trials and review articles.
Selection criteria: All randomized controlled trials where BIS was used during anesthesia (and the control groups being clinical criteria only) were selected.
Data collection & analysis: Two reviewers independently extracted data for the anaesthetic consumption, recovery time, duration of stay in post anaesthetic care unit (PACU), time to home readiness, incidence of recall of intraoperative awareness and the cost of anaesthesia management. Appropriate statistic methods from Review Manager 4.2.2 were used to examine and combine the result across the studies.
Results: Searching identified 17 studies. Nine studies with data from a total of 719 patients were considered eligible for analysis. The BIS monitor was used to guide the dose of propofol (2 studies), sevoflurane (4 studies), desflurane (2 studies) and isoflurane (1 study). There was clinical heterogeneity across the studies regarding type of anaesthetics, method of administration, and clinical criteria. Two studies consistently reported a decrease in propofol consumption in the BIS group. The report of volatile anaesthetic consumption varied across the studies. There were consistently reports of faster immediate recovery time in the BIS group across the studies in terms of time to response to command (7 studies, 542 patients), time to extubation (5 studies,422 patients) and time to orientation (4 studies, 166 patients) with overall effects (95% CI) of 2.05(-3.18,-0.92), -2.49(-3.89,-1.09) and 2.01 (-2.82,-1.19) minutes respectively. The report of duration of PACU stay was not consitent across the studies. In ambulatory setting (4 studies, 210 patients), there was no difference in time to home readiness with the weight mean difference (95%CI) of 3.80 (-15.25, 22.85) min. There was no report of intraoperative recall awareness in patients of both groups. The total cost of drugs used during anaesthesia was calculated in only one study and was lower in the BIS group.
Conclusions: Despite clinical heterogeneity across the studies, the use of BIS values in guiding the dose of anaesthetics could improve the immediate recovery time. More controlled trials with high quality and definite protocol for anaethetic delivery should be sought or conducted to evaluate the use of BIS monitoring during anaesthesia in terms of improved quality of care, effectiveness and efficiency.
Acknowledments: We would like to thank Jane Cracknell, Cochrane Anaesthesia Review Group Co-ordinator.
Objectives: This review focuses on whether BIS incorporated into the standard practice of anaesthesia management can reduce the anaesthetic consumption, recovery time, incidence of recall awareness during operation and the total cost of anaesthesia management.
Search strategy: Published studies were searched from the MEDLINE (1966 to 2003), EMBASE (1966 to 2003) , the Conchrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library, issue 2, 2003 ) and the reference lists of trials and review articles.
Selection criteria: All randomized controlled trials where BIS was used during anesthesia (and the control groups being clinical criteria only) were selected.
Data collection & analysis: Two reviewers independently extracted data for the anaesthetic consumption, recovery time, duration of stay in post anaesthetic care unit (PACU), time to home readiness, incidence of recall of intraoperative awareness and the cost of anaesthesia management. Appropriate statistic methods from Review Manager 4.2.2 were used to examine and combine the result across the studies.
Results: Searching identified 17 studies. Nine studies with data from a total of 719 patients were considered eligible for analysis. The BIS monitor was used to guide the dose of propofol (2 studies), sevoflurane (4 studies), desflurane (2 studies) and isoflurane (1 study). There was clinical heterogeneity across the studies regarding type of anaesthetics, method of administration, and clinical criteria. Two studies consistently reported a decrease in propofol consumption in the BIS group. The report of volatile anaesthetic consumption varied across the studies. There were consistently reports of faster immediate recovery time in the BIS group across the studies in terms of time to response to command (7 studies, 542 patients), time to extubation (5 studies,422 patients) and time to orientation (4 studies, 166 patients) with overall effects (95% CI) of 2.05(-3.18,-0.92), -2.49(-3.89,-1.09) and 2.01 (-2.82,-1.19) minutes respectively. The report of duration of PACU stay was not consitent across the studies. In ambulatory setting (4 studies, 210 patients), there was no difference in time to home readiness with the weight mean difference (95%CI) of 3.80 (-15.25, 22.85) min. There was no report of intraoperative recall awareness in patients of both groups. The total cost of drugs used during anaesthesia was calculated in only one study and was lower in the BIS group.
Conclusions: Despite clinical heterogeneity across the studies, the use of BIS values in guiding the dose of anaesthetics could improve the immediate recovery time. More controlled trials with high quality and definite protocol for anaethetic delivery should be sought or conducted to evaluate the use of BIS monitoring during anaesthesia in terms of improved quality of care, effectiveness and efficiency.
Acknowledments: We would like to thank Jane Cracknell, Cochrane Anaesthesia Review Group Co-ordinator.