title: The influence of a muscle relaxant bolus on bispectral and datex-ohmeda entropy values during propofol-remifentanil induced loss of consciousness.
abstract: Studies investigating the influence of muscle relaxants on the bispectral index have yielded contradictory results. In our prospective, randomized, double-blind experiments, patients received a fixed target concentration of remifentanil along with a target-controlled infusion of propofol, titrated until loss of consciousness. Two minutes after loss of consciousness, the study group received a bolus injection of atracurium, whereas the control group received a placebo. The following variables were recorded: bispectral index, spectral edge frequency, electromyographic activity, state entropy, and response entropy provided by the Datex-Ohmeda Entropy monitor. Similar values were obtained in both groups at loss of consciousness. Placebo administration induced a decrease in bispectral index (P < 0.002), spectral edge frequency (P < 0.05), electromyographic activity (P < 0.02), state entropy (P < 0.05), and response entropy (P < 0.01) compared with the values measured at loss of consciousness. Atracurium administration induced a decrease in bispectral index (P < 0.0001), spectral edge frequency (P < 0.01), electromyographic activity (P < 0.0001), state entropy (P < 0.0001), and response entropy (P < 0.0001) values. Decreases in bispectral index (P < 0.05), electromyographic activity (P < 0.0001), and response entropy (P < 0.01) were larger after atracurium than placebo injection. In lightly anesthetized patients, myorelaxant administration decreases bispectral index and response entropy, but not state entropy values.
authors.affiliation: *Department of Anesthesiology, Hôpital Foch, Suresnes, France; †Department of Anesthesiology, Hôpital Erasme, ULB, Brussels, Belgium.
authors.forename: Ngai
authors.initials: N
authors.lastname: Liu
authors.forename: Thierry
authors.initials: T
authors.lastname: Chazot
authors.forename: Isabelle
authors.initials: I
authors.lastname: Huybrechts
authors.forename: Jean-Dominique
authors.initials: JD
authors.lastname: Law-Koune
authors.forename: Luc
authors.initials: L
authors.lastname: Barvais
authors.forename: Marc
authors.initials: M
authors.lastname: Fischler
mesh_terms: D000328:Adult; D000368:Aged; D000771:Anesthesia, Intravenous; D001279:Atracurium / Q000494:pharmacology*; D004311:Double-Blind Method; D004569:Electroencephalography / Q000187:drug effects*; D004576:Electromyography / Q000187:drug effects; D019277:Entropy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D010880:Piperidines / Q000008:administration & dosage*; D015742:Propofol / Q000008:administration & dosage*; D011446:Prospective Studies; D000077208:Remifentanil
chemical_list: D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D001279:Atracurium; D000077208:Remifentanil; D015742:Propofol