title: The effect of propofol on patient reaction time and its relationship with loss of verbal contact before induction of anaesthesia.
abstract: Increasing the calculated plasma concentration of propofol has been shown to increase choice reaction time and visual and auditory response times. We studied the relationship of reaction to a vibrating handset as the effect-site target-controlled propofol concentration was incrementally increased in 20 patients during sedation, before induction of general anaesthesia. The reaction time increased, initially slowly and then more rapidly, as the calculated effect-site concentration of propofol increased, until the reaction to the vibrating handset was lost at a mean (SD) propofol effect-site concentration of 2.0 (0.6) μg.ml(-1) . The loss of response to verbal contact occurred at a propofol effect-site concentration of 2.4 (0.5) μg.ml(-1) . Reaction time may be of use clinically to warn of impending loss of verbal contact.
authors.affiliation: Department of Anesthesia, Foothills Medical Centre, Calgary, Alberta, Canada.
authors.forename: K J
authors.initials: KJ
authors.lastname: Anderson
authors.forename: S
authors.initials: S
authors.lastname: Allam
authors.forename: R
authors.initials: R
authors.lastname: Chapman
authors.forename: G N C
authors.initials: GN
authors.lastname: Kenny
mesh_terms: D000328:Adult; D016058:Analgesia, Patient-Controlled / Q000379:methods*; D000768:Anesthesia, General / Q000379:methods*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D015742:Propofol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects*; D012646:Self Administration / Q000379:methods; D013060:Speech / Q000187:drug effects*
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol