This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (25) Citing Articles via Google Scholar Google Scholar Articles by Greif, R. Articles by Sessler, D. I. Search for Related Content PubMed PubMed Citation Articles by Greif, R. Articles by Sessler, D. I. Related Collections Pharmacology

---

ANESTHETIC PHARMACOLOGY

Muscle Relaxation Does Not Alter Hypnotic Level During Propofol Anesthesia

Robert Greif, MD^*, Scott Greenwald, PhD, Ekkehard Schweitzer, MD, Sonja Laciny, MD^*, Angela Rajek, MD, James E. Caldwell, MB ChB^||, and Daniel I. Sessler, MD^¶

*Department of Anesthesiology and Intensive Care Medicine, Donauspital-SMZO, Vienna, Austria; Director of Research, Aspect Medical Systems, Inc., Newton, Massachussetts; Department of Anesthesia and Intensive Care, Krankenhaus Lainz; Ludwig Boltzmann Institute for Economics of Medicine in Anesthesia and Intensive Care, Vienna, Austria; Department of Cardiothoracic and Vascular Anesthesia, University of Vienna, Vienna, Austria; ||Department of Anesthesia and Perioperative Care, University of California—San Francisco, San Francisco, California, and ¶Outcomes Research Institute, University of Louisville, Louisville, Kentucky and Ludwig Boltzmann Institute, University of Vienna, Vienna, Austria

Address correspondence to Daniel I. Sessler, MD, University of Louisville, Abell Administration Center, Room 217, 323 East Chestnut Street, Louisville, KY 40202-3866. Address e-mail to sessler{at}louisville.edu

Electromyographic (EMG) activity can contaminate electroencephalographic signals. Paralysis may therefore reduce the Bispectral Index (BIS) by alleviating artifact from muscles lying near the electrodes. Paralysis may also reduce signals from muscle stretch receptors that normally contribute to arousal. We therefore tested the hypothesis that nondepolarizing neuromuscular block reduces BIS. Ten volunteers were anesthetized with propofol at a target effect site concentration of 3.8 ± 0.4 µg/mL. A mivacurium infusion was adjusted to vary the first twitch (T1) in a train-of-four to 80%, 30%, 20%, 15%, 10%, 5%, or 2% of the prerelaxant intensity. At each randomly assigned T1, we measured BIS and frontal-temporal EMG intensity. BIS averaged 95 ± 4 before induction of anesthesia, and decreased significantly to 40 ± 5 after propofol administration. However, there were no significant differences at the designated block levels. Frontal-temporal EMG intensity averaged 47 ± 3 dB before induction of anesthesia, and decreased significantly to 27 ± 1 dB after propofol administration. However, there were no significant differences at the designated block levels. These data suggest that the BIS level and EMG tone are unaltered by mivacurium administration during propofol anesthesia.

IMPLICATIONS: Neuromuscular block level did not alter Bispectral Index (BIS) during propofol anesthesia, either by reducing electromyographic artifact or by decreasing afferent neuronal input. The BIS will thus comparably estimate sedation in deeply unconscious patients who are paralyzed, partially paralyzed, or unparalyzed.

This article has been cited by other articles:

				A. G. Doufas, R. Komatsu, M. Orhan-Sungur, P. Sengupta, A. Wadhwa, E. Mascha, S. L. Shafer, and D. I. Sessler Neuromuscular Block Differentially Affects Immobility and Cortical Activation at Near-Minimum Alveolar Concentration Anesthesia Anesth. Analg., October 1, 2009; 109(4): 1097 - 1104. [Abstract] [Full Text] [PDF]

				M. Kawaguchi, I. Takamatsu, and T. Kazama Rocuronium dose-dependently suppresses the spectral entropy response to tracheal intubation during propofol anaesthesia Br. J. Anaesth., May 1, 2009; 102(5): 667 - 672. [Abstract] [Full Text] [PDF]

				V. Bonhomme and P. Hans Muscle relaxation and depth of anaesthesia: where is the missing link? Br. J. Anaesth., October 1, 2007; 99(4): 456 - 460. [Full Text] [PDF]

				A. Ekman, E. Stalberg, E. Sundman, L. I. Eriksson, L. Brudin, and R. Sandin The Effect of Neuromuscular Block and Noxious Stimulation on Hypnosis Monitoring During Sevoflurane Anesthesia Anesth. Analg., September 1, 2007; 105(3): 688 - 695. [Abstract] [Full Text] [PDF]

				L. I. Cortinez, A. E. Delfino, R. Fuentes, and H. R. Munoz Performance of the Cerebral State Index During Increasing Levels of Propofol Anesthesia: A Comparison with the Bispectral Index Anesth. Analg., March 1, 2007; 104(3): 605 - 610. [Abstract] [Full Text] [PDF]

				V. L. B. Oei-Lim, M. G. W. Dijkgraaf, M. D. de Smet, M. White, and C. J. Kalkman Does Cerebral Monitoring Improve Ophthalmic Surgical Operating Conditions During Propofol-Induced Sedation? Anesth. Analg., November 1, 2006; 103(5): 1189 - 1195. [Abstract] [Full Text] [PDF]

				M. T. V. Chan and T. Gin Changes of bispectral index after a bolus dose of muscle relaxant. Anesth. Analg., September 1, 2006; 103(3): 776 - 777. [Full Text] [PDF]

				N. Liu, T. Chazot, I. Huybrechts, J.-D. Law-Koune, L. Barvais, and M. Fischler The Influence of a Muscle Relaxant Bolus on Bispectral and Datex-Ohmeda Entropy Values During Propofol-Remifentanil Induced Loss of Consciousness Anesth. Analg., December 1, 2005; 101(6): 1713 - 1718. [Abstract] [Full Text] [PDF]

				A. A. Dahaba Different Conditions That Could Result in the Bispectral Index Indicating an Incorrect Hypnotic State Anesth. Analg., September 1, 2005; 101(3): 765 - 773. [Abstract] [Full Text] [PDF]

				H. Heller, R. Hatami, P. Mullin, R. R. Sciacca, A. G. Khandji, M. Hamberger, R. Emerson, and E. J. Heyer Bilateral Bispectral Index Monitoring During Suppression of Unilateral Hemispheric Function Anesth. Analg., July 1, 2005; 101(1): 235 - 341. [Abstract] [Full Text] [PDF]

				F. C. Vasella, P. Frascarolo, D. R. Spahn, and L. Magnusson Antagonism of neuromuscular blockade but not muscle relaxation affects depth of anaesthesia Br. J. Anaesth., June 1, 2005; 94(6): 742 - 747. [Abstract] [Full Text] [PDF]

				P. Hans, P.-Y. Dewandre, J. F. Brichant, and V. Bonhomme Comparative effects of ketamine on Bispectral Index and spectral entropy of the electroencephalogram under sevoflurane anaesthesia Br. J. Anaesth., March 1, 2005; 94(3): 336 - 340. [Abstract] [Full Text] [PDF]

				A. A. Dahaba, M. Mattweber, A. Fuchs, W. Zenz, P. H. Rehak, W. F. List, and H. Metzler The Effect of Different Stages of Neuromuscular Block on the Bispectral Index and the Bispectral Index-XP Under Remifentanil/Propofol Anesthesia Anesth. Analg., September 1, 2004; 99(3): 781 - 787. [Abstract] [Full Text] [PDF]

				G. Schneider, A. W. Gelb, B. Schmeller, R. Tschakert, and E. Kochs Detection of awareness in surgical patients with EEG-based indices--bispectral index and patient state index{dagger}{ddagger} Br. J. Anaesth., September 1, 2003; 91(3): 329 - 335. [Abstract] [Full Text] [PDF]

				N. B. McDermott, T. VanSickle, D. Motas, and R. H. Friesen Validation of the Bispectral Index Monitor During Conscious and Deep Sedation in Children Anesth. Analg., July 1, 2003; 97(1): 39 - 43. [Abstract] [Full Text] [PDF]