Closed loop control of sedation for colonoscopy using the Bispectral Index.
Sixteen patients undergoing colonoscopy were sedated with propofol using a closed-loop control system guided by the Bispectral Index (BIS). Propofol administration, via a target-controlled infusion, was controlled by a proportional-integral-differential control algorithm. The median (range) propofol target concentration during closed-loop control was 2.3 (1.7-3.6) microg.ml(-1). The performance characteristics of the system were excellent, with a median absolute performance error of 7 (1-15). Patients were drowsy yet rousable, with a median (range) BIS set-point of 80 (75-85). No patient became apnoeic, required airway support or became haemodynamically unstable whilst sedated. Eight patients moaned or moved during colonoscopy and four had recall. Median (range) time to full consciousness was 4 (2-20) min after the end of closed-loop control. Patient and surgeon satisfaction were high. We conclude that BIS may be a suitable control variable for closed-loop control of sedation with propofol.
University Department of Anaesthesia, Southern General Hospital, Glasgow, Scotland, UK. kate.leslie@mh.org.au
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Absalom
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Kenny
D000328:Adult; D000368:Aged; D000465:Algorithms; D000764:Anesthesia, Closed-Circuit; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D003113:Colonoscopy; D016292:Procedural Sedation / Q000379:methods*; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D015742:Propofol / Q000008:administration & dosage
D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D015742:Propofol