title: Differences between bispectral index and spectral entropy during xenon anaesthesia: a comparison with propofol anaesthesia.
abstract: We enrolled 114 patients, aged 65-83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy.
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: J
authors.initials: J
authors.lastname: Höcker
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: B
authors.initials: B
authors.lastname: Raitschew
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: P
authors.initials: P
authors.lastname: Meybohm
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: O
authors.initials: O
authors.lastname: Broch
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: C
authors.initials: C
authors.lastname: Stapelfeldt
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: M
authors.initials: M
authors.lastname: Gruenewald
authors.affiliation:  Staff Anaesthesiologist.
authors.forename: E
authors.initials: E
authors.lastname: Cavus
authors.affiliation:  Professor and Chair.
authors.forename: M
authors.initials: M
authors.lastname: Steinfath
authors.affiliation:  Associate Professor, Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Bein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D019277:Entropy; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods; D015742:Propofol / Q000494:pharmacology*; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D014978:Xenon / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D014978:Xenon; D015742:Propofol
references.citation: Rossaint R, Reyle-Hahn M, Schulte Am Esch J, et al. Multicenter randomized comparison of the efficacy and safety of xenon and isoflurane in patients undergoing elective surgery. Anesthesiology 2003; 98: 6-13.
references.citation: Ma D, Sanders RD, Halder S, Rajakumaraswamy N, Franks NP, Maze M. Xenon exerts age-independent antinociception in Fischer rats. Anesthesiology 2004; 100: 1313-8.
references.citation: Bein B, Turowski P, Renner J, et al. Comparison of xenon-based anaesthesia compared with total intravenous anaesthesia in high risk surgical patients. Anaesthesia 2005; 60: 960-7.
references.citation: Coburn M, Kunitz O, Baumert JH, et al. Randomized controlled trial of the haemodynamic and recovery effects of xenon or propofol anaesthesia. British Journal of Anaesthesia 2005; 94: 198-202.
references.citation: Schmidt M, Marx T, Gloggl E, Reinelt H, Schirmer U. Xenon attenuates cerebral damage after ischemia in pigs. Anesthesiology 2005; 102: 929-36.
references.citation: Wilhelm S, Ma D, Maze M, Franks NP. Effects of xenon on in vitro and in vivo models of neuronal injury. Anesthesiology 2002; 96: 1485-91.
references.citation: Jones MV, Harrison NL, Pritchett DB, Hales TG. Modulation of the GABAA receptor by propofol is independent of the gamma subunit. Journal of Pharmacology and Experimental Therapeutics 1995; 274: 962-8.
references.citation: Nishikawa K, Harrison NL. The actions of sevoflurane and desflurane on the gamma-aminobutyric acid receptor type A: effects of TM2 mutations in the alpha and beta subunits. Anesthesiology 2003; 99: 678-84.
references.citation: Ekman A, Lindholm ML, Lennmarken C, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiologica Scandinavica 2004; 48: 20-6.
references.citation: Gan TJ, Glass PS, Windsor A, et al. Bispectral index monitoring allows faster emergence and improved recovery from propofol, alfentanil, and nitrous oxide anesthesia. BIS Utility Study Group. Anesthesiology 1997; 87: 808-15.
references.citation: Liu SS. Effects of Bispectral Index monitoring on ambulatory anesthesia: a meta-analysis of randomized controlled trials and a cost analysis. Anesthesiology 2004; 101: 311-5.
references.citation: Rampil IJ. A primer for EEG signal processing in anesthesia. Anesthesiology 1998; 89: 980-1002.
references.citation: Viertio-Oja H, Maja V, Sarkela M, et al. Description of the entropy algorithm as applied in the Datex-Ohmeda S/5 Entropy Module. Acta Anaesthesiologica Scandinavica 2004; 48: 154-61.
references.citation: Hans P, Dewandre PY, Brichant JF, Bonhomme V. Comparative effects of ketamine on Bispectral Index and spectral entropy of the electroencephalogram under sevoflurane anaesthesia. British Journal of Anaesthesia 2005; 94: 336-40.
references.citation: Laitio RM, Kaskinoro K, Sarkela MO, et al. Bispectral index, entropy, and quantitative electroencephalogram during single-agent xenon anesthesia. Anesthesiology 2008; 108: 63-70.
references.citation: Marsh B, White M, Morton N, Kenny GN. Pharmacokinetic model driven infusion of propofol in children. British Journal of Anaesthesia 1991; 67: 41-8.
references.citation: Aldrete JA. The post-anesthesia recovery score revisited. Journal of Clinical Anesthesia 1995; 7: 89-91.
references.citation: Goto T, Nakata Y, Saito H, et al. Bispectral analysis of the electroencephalogram does not predict responsiveness to verbal command in patients emerging from xenon anaesthesia. British Journal of Anaesthesia 2000; 85: 359-63.
references.citation: Bonhomme V, Deflandre E, Hans P. Correlation and agreement between bispectral index and state entropy of the electroencephalogram during propofol anaesthesia. British Journal of Anaesthesia 2006; 97: 340-6.
references.citation: Meybohm P, Gruenewald M, Höcker J, et al. Correlation and agreement between the bispectral index vs. state entropy during hypothermic cardio-pulmonary bypass. Acta Anaesthesiologica Scandinavica 2010; 54: 169-75.
references.citation: Ellerkmann RK, Liermann VM, Alves TM, et al. Spectral entropy and bispectral index as measures of the electroencephalographic effects of sevoflurane. Anesthesiology 2004; 101: 1275-82.
references.citation: White PF, Tang J, Romero GF, et al. A comparison of state and response entropy versus bispectral index values during the perioperative period. Anesthesia & Analgesia 2006; 102: 160-7.
references.citation: Franks NP, Dickinson R, De Sousa SL, Hall AC, Lieb WR. How does xenon produce anaesthesia? Nature 1998; 396: 324.
references.citation: Cullen SC, Eger EI II, Cullen BF, Gregory P. Observations on the anesthetic effect of the combination of xenon and halothane. Anesthesiology 1969; 31: 305-9.
references.citation: Rasmussen LS, Schmehl W, Jakobsson J. Comparison of xenon with propofol for supplementary general anaesthesia for knee replacement: a randomized study. British Journal of Anaesthesia 2006; 97: 154-9.
references.citation: Baumert JH, Hein M, Hecker KE, Satlow S, Neef P, Rossaint R. Xenon or propofol anaesthesia for patients at cardiovascular risk in non-cardiac surgery. British Journal of Anaesthesia 2008; 100: 605-11.
references.citation: Wappler F, Rossaint R, Baumert J, et al. Multicenter randomized comparison of xenon and isoflurane on left ventricular function in patients undergoing elective surgery. Anesthesiology 2007; 106: 463-71.
references.citation: Coburn M, Kunitz O, Apfel CC, Hein M, Fries M, Rossaint R. Incidence of postoperative nausea and emetic episodes after xenon anaesthesia compared with propofol-based anaesthesia. British Journal of Anaesthesia 2008; 100: 787-91.