Utilizing Bi-Spectral Index (BIS) for the monitoring of sedated adult ICU patients: a systematic review

Abstract

BACKGROUND: The ideal level of sedation in the ICU is an ongoing source of scrutiny. At higher levels of sedation, the current scoring systems are not ideal. BIS may be able to improve both. We evaluated literature on effectiveness of BIS monitoring in sedated mechanically ventilated (MV) ICU patients compared to clinical sedation scores (CSS). EVIDENCE ACQUISITION: For this systematic review, full text articles were searched in OVID, MEDLINE, EMBASE, and Cochrane databases from 1986-2014. Additional studies were identified searching bibliographies/abstracts from national/international Critical Care Medicine conferences and references from searched articles retrieved. Search terms were: Clinical sedation scale, Bi-Spectral Index, Mechanical ventilation, Intensive Care Unit. Included were prospective, randomized and non-randomized studies comparing BIS monitoring with any CSS in MV adult (> 18 year old) ICU patients. Studies were graded for quality of evidence based on bias as established by the GRADE guidelines. Additional sources of bias were examined. EVIDENCE SYNTHESIS: There were five studies which met inclusion criteria. All five studies were either unclear or at high risk of bias for blinding of participants and blinding of outcome assessment. All papers had at least one source of additional high risk, or unclear/unstated bias. CONCLUSIONS: BIS monitoring in the mechanically ventilated ICU patient may decrease sedative drug dose, recall, and time to wake-up. The studies suggesting this are severely limited methodologically. BIS, when compared to subjective CSSs, is not, at this time, clearly indicated. An appropriately powered randomized, controlled study is needed to determine if this monitoring modality is of use on the ICU.