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 PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Dahaba, A. A. Articles by Metzler, H. Search for Related Content PubMed PubMed Citation Articles by Dahaba, A. A. Articles by Metzler, H. Related Collections Neuroanesthesia Monitoring (Non-cardiac) Technology

---

NEUROSURGICAL ANESTHESIOLOGY AND NEUROSCIENCE

Bispectral Index Monitoring of a Narcolepsy-Cataplexy Episode During Regional Anesthesia

Ashraf A. Dahaba, MD, MSc, PhD^*, Guo Xun Xu, MD, Qing Hai Liu, MD, Ji Xiu Xue, MD, and Helfried Metzler, MD^*

From the *Department of Anesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria; and Department of Anesthesiology, Xuan Wu Hospital, Capital Medical University, Beijing, People's Republic of China.

Address correspondence and reprint requests to Dr. Tian Long Wang, Chairman of the Department of Anaesthesiology, Capital Medical University, Beijing, People's Republic of China. Address e-mail to ashraf.dahaba{at}medunigraz.at.

Abstract

Narcolepsy or Gélineau syndrome is an extremely incapacitating chronic sleep disorder of unknown etiology that is characterized by uncontrollable attacks of deep sleep and is typically associated with cataplexy sudden loss of muscle tone. The Bispectral Index (BIS), an electroencephalographic-derived cerebral monitor, used for monitoring the effects of anesthetic/hypnotic drugs was shown to correlate to various conditions that could influence the eletroencephalogram. We assessed the utility of using BIS for monitoring a possible narcolepsy-cataplexy episode and whether a distinctive BIS profile might offer an early warning of an impending narcoleptic/cataplectic spell. We recorded both hemispheres, using two synchronized BIS-XP monitors, during a narcolepsy-cataplexy episode in a 57-yr-old male patient undergoing lower limb surgery under femoral nerve block regional anesthesia. The patient went through three stages: first a prodromal "intermittent low-vigilance" phase interrupted by high electromyographic activity. This was followed by a second "continuous low-vigilance" phase of BIS around 75 with low electromyographic activity, ending with a third "nonresponsive vigilance" phase of a full-blown narcolepsy-cataplexy episode of BIS around 45 with complete loss of muscle power. The purpose of presenting this report is to emphasize the fact that narcoleptic patients can still run the risk of loss of consciousness with atonia under regional anesthesia, and such an undesirable complication cannot be under-estimated. BIS monitoring is a simple method that could offer an early warning of an imminent episode, with its associated hazards, in patients with narcolepsy-cataplexy undergoing surgery under regional anesthesia.