Comparison of bispectral EEG analysis and auditory evoked potentials for monitoring depth of anaesthesia during propofol anaesthesia

• Published in: British Journal of Anaesthesia Vol. 82; no. 5; pp. 672 - 678
• Main Authors: Gajraj, R J, Doi, M, Mantzaridis, H, Kenny, G N
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01-05-1999; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Adolescent; Adult; Ambulatory Surgical Procedures; Anesthesia; Anesthesia, General; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthetics, Intravenous - pharmacology; Biological and medical sciences; Consciousness - drug effects; Consciousness - physiology; Electroencephalography - drug effects; Evoked Potentials, Auditory - drug effects; Female; General anesthesia. Technics. Complications. Neuromuscular blocking. Premedication. Surgical preparation. Sedation; Humans; Male; Medical sciences; Middle Aged; Monitoring, Intraoperative - methods; Propofol - pharmacology; Human; Electrodiagnosis; General anesthetic; Auditory evoked potential; General anesthesia; Exploration; Spontaneous ventilation; Electroencephalography; Propofol; Spectral analysis; Comparative study; Monitoring
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/82.5.672

We have compared the auditory evoked potential index (AEPIndex) and bispectral index (BIS) for monitoring depth of anaesthesia in spontaneously breathing surgical patients. Twenty patients (aged 17-49 yr) undergoing day surgery were anaesthetized with computer-controlled infusions of propofol. The mean (SD and range) of each measurement was determined during consciousness and unconsciousness and at specific times during the perioperative period. Mean values for AEPIndex during consciousness and unconsciousness were 74.5 (SD 14.7) 36.7 (7.1), respectively. BIS had mean values of 89.5 (SD 4.6) during consciousness and 48.8 (16.4) during unconsciousness. AEPIndex and BIS were greater during consciousness compared with during unconsciousness. The average awake values of AEPIndex were significantly higher than all average values during unconsciousness but this was not the case for BIS. BIS increased gradually during emergence from anaesthesia and may therefore be able to predict recovery of consciousness at the end of anaesthesia. AEPIndex was more able to detect the transition from unconsciousness to consciousness.