Performance of the ARX-derived auditory evoked potential Index as an indicator of anesthetic depth: A comparison with Bispectral Index and hemodynamic measures during propofol administration

• Published in: Anesthesiology (Philadelphia) Vol. 96; no. 4; pp. 803 - 816
• Main Authors: STRUYS, Michel M. R. F, JENSEN, Erik Weber, SMITH, Warren, SMITH, N. Ty, RAMPIL, Ira, DUMORTIER, Frank J. E, MESTACH, Christel, MORTIER, Eric P
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott 01.04.2002
• Subjects: Adolescent; Adult; Anesthesia; Anesthesia, Intravenous; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Consciousness; Electrodiagnosis. Electric activity recording; Electroencephalography - drug effects; Evoked Potentials, Auditory - drug effects; Female; General anesthesia. Technics. Complications. Neuromuscular blocking. Premedication. Surgical preparation. Sedation; Hemodynamics - drug effects; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Middle Aged; Movement; Nervous system; Propofol - pharmacology; Sensitivity and Specificity; Human; Electrodiagnosis; General anesthetic; Auditory evoked potential; General anesthesia; Electroencephalography; Hemodynamics; Propofol; Spectral analysis; Comparative study; Monitoring
• ISSN: 0003-3022; 1528-1175
• DOI: 10.1097/00000542-200204000-00006

Autoregressive modeling with exogenous input of middle-latency auditory evoked potential (A-Line autoregressive index [AAI]) has been proposed for monitoring anesthetic depth. The aim of the current study was to compare the accuracy of this new index with the Bispectral Index (BIS), predicted effect-site concentration of propofol, and hemodynamic measures. Twenty female patients scheduled for ambulatory gynecologic surgery received effect compartment controlled infusion of propofol. Target effect-site concentration was started at 1.5 microg/ml and increased every 4 min by 0.5 microg/ml. At every step, sedation level was compared with monitoring values using different clinical scoring systems and reaction to noxious stimulus. Bispectral Index, AAI, and predicted propofol effect-site concentration were accurate indicators for the level of sedation and loss of consciousness. Hemodynamic variables were poor indicators of the hypnotic-anesthetic status of the patient. BIS correlated best with propofol effect-site concentration, followed by AAI. Hemodynamic measurements did not correlate well. No indicators predicted reaction to noxious stimulus. Poststimulus, BIS and AAI showed an increase as a result of arousal. This reaction occurred more rapidly with the AAI than with BIS. Bispectral Index, AAI, and predicted propofol effect-site concentration revealed information on the level of sedation and loss of consciousness but did not predict response to noxious stimulus.