PSY4 - Bis Sensor Versus Conventional Anesthetic Monitoring: Systematic Review on Patient-Oriented Outcomes

Abstract

Adult patients who receive general anesthesia may not remain totally unconscious during surgery despite of anesthetics and analgesics care received. The retention of memory due to intraoperative awareness may cause serious clinical complications, requiring 1071 patients monitored to prevent the occurrence of one event. The proper conventional maintenance of general anesthesia is assessed with clinical signs or expired gases (ETAC/ETAG/ETCO2). Bi-Spectral Index Monitoring or BIS Sensor is a neurophysiological evaluation system that continually analyzes EEG to determine the level of intraoperative awareness. We have made a literature search in PubMed to identify systematic reviews and randomized controlled trials that studied level of consciousness intraoperative or postoperative memory when used these alternatives of anesthetic monitoring. We have found nine RCT and two systematic reviews published until April 2013 and conducted our own meta-analysis on seven trials. Two studies were excluded from the synthesis for not presenting the outcome of primary interest. Three RCT of moderate heterogeneity showed no difference in the occurrence of intraoperative awareness between the BIS group and the ETAC/ETAG/ETCO2 group. The quality of evidence was considered high in one study, moderate and low in the others (26,490 patients, I2 = 45.9%, RR = 1.28, 95% CI = 0.54 to 3.03, p = 0.57). Four clinical monitoring control group studies with no heterogeneity showed that the sensor BIS was more effective, requiring between 71 and 167 patients monitored for an event of intraoperative awareness avoided. The quality of evidence of the studies was considered high (7,779 patients, I2 = 0.0%, RR = 0.42, 95% CI = 0.27 to 0.65, p = 0, 0.0001). Clinical trials published until April 2013 showed favorable results in patient-oriented outcomes of BIS group when compared to clinical monitoring group but not to ETAC/ETAG/ETCO2 group.