title: Response entropy changes after noxius stimulus.
abstract: Small changes in the frequency of the electromyography could reflect an inadequate anesthetic or analgesic level, and it could be more specific than the hemodynamic monitors. The Datex-Ohmeda S/5 Entropy Module includes information about the electromyographic activity of the face muscles (response entropy--RE). The aim of our study is compare entropy and BIS ability to detect a nociceptive stimulus during a sevoflurane anesthesia. We designed an observational, prospective and descriptive study that included 20 patients. We performed sevoflurane anaesthesia induction, the end-tidal was kept at 3 and 4 %, during 15 min at each concentration, with no analgesic drug and no neuromuscular blocking agent, and we applied a nociceptive stimulus: tetanus 100 Hz, during 5 s. We set the standard monitorization, BIS, RE, and state entropy (SE) along the study. There was a significant difference between RE and SE post-noxious stimulus values at 3 and 4 % end-tidal sevoflurane (p < 0.05). Only RE changed significantly at the moment of the noxious stimulation at both sevoflurane concentrations studied (p < 0.05). In patients under general anesthesia only carried out with sevoflurane at concentrations that inhibit the movement to painful stimuli, the RE is a single parameter able to detect variations after the nociceptive stimulation.
authors.affiliation: Department of Anesthesiology, Hospital Universitario Virgen de la Victoria, Campus Universitario Teatinos, C.P. 29010, Malaga, Spain. guerreroorriach@terra.es
authors.forename: Jose L
authors.initials: JL
authors.lastname: Guerrero
authors.forename: E
authors.initials: E
authors.lastname: Matute
authors.forename: E
authors.initials: E
authors.lastname: Alsina
authors.forename: B
authors.initials: B
authors.lastname: Del Blanco
authors.forename: F
authors.initials: F
authors.lastname: Gilsanz
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation; D004558:Electric Stimulation; D004576:Electromyography / Q000706:statistics & numerical data*; D019277:Entropy; D005152:Facial Muscles / Q000502:physiology; D006801:Humans; D008738:Methyl Ethers; D016343:Monitoring, Intraoperative / Q000706:statistics & numerical data*; D059225:Nociception; D011446:Prospective Studies; D000077149:Sevoflurane; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane