Effects of Bispectral Index Monitoring on Ambulatory Anesthesia

BACKGROUND: Ambulatory surgery is growing in popularity worldwide. For example, 50-70% of surgical procedures in North America are performed on an ambulatory basis. Use of Bispectral Index (BIS) monitoring for titration of general anesthesia may allow use of less anesthetics, reduction in side effects, and faster patient recovery. METHODS: MEDLINE and other databases were searched for randomized controlled trials examining the use of BIS monitoring versus standard practice in ambulatory surgery patients. Outcomes were extracted from these articles, and a meta-analysis was performed. RESULTS: One thousand three hundred eighty subjects from 11 trials were included in the meta-analysis. The use of BIS monitoring significantly reduced anesthetic consumption by 19%, reduced the incidence of nausea/vomiting (32% vs. 38%; odds ratio, 0.77), and reduced time in the recovery room by 4 min. However, these benefits did not result in significant reduction in time until patient discharge from the ambulatory surgery unit. Cost analysis using pooled costs to reflect North America, Europe, and Asia indicated that use of BIS monitoring increased the cost per patient by 5.55 US dollars because of the cost of BIS electrodes. CONCLUSIONS: The use of BIS monitoring modestly reduced anesthetic consumption, risk of nausea and vomiting, and recovery room time. These benefits did not reduce time spent in the ambulatory surgery unit, and cost of the BIS electrode exceeded any cost savings.