Relationship between calculated blood concentration of propofol and electrophysiological variables during emergence from anaesthesia: comparison of bispectral index, spectral edge frequency, median frequency and auditory evoked potential index.
We studied four electrophysiological variables (bispectral index (BIS), 95% spectral edge frequency (SEF), median frequency (MF) and auditory evoked potential index (AEP index) in 10 patients during emergence from anaesthesia. We compared correlation of the signals with gradually decreasing calculated blood propofol concentrations, and evaluated the signal differences between preinduction and emergence from anaesthesia. Values of BIS, MF and SEF correlated with calculated blood concentrations of propofol during emergence from anaesthesia. The correlation was best with BIS, but was poor with MF and SEF at low calculated blood propofol concentrations. Although AEP index values did not correlate with calculated blood concentrations of propofol during emergence from anaesthesia, values after eye opening and before anaesthesia were well distinguished from those during emergence from anaesthesia. BIS correlated best with calculated blood concentrations of propofol. AEP index appeared to distinguish the awake from asleep state.
Doi
M
M
Department of Anaesthesia, HCI International Medical Centre, Clydebank.
Gajraj
R J
RJ
Mantzaridis
H
H
Kenny
G N
GN
D000293:Adolescent; D000328:Adult; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000097:blood* / Q000494:pharmacology; D003243:Consciousness / Q000187:drug effects / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects*; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D013511:Minor Surgical Procedures; D015742:Propofol / Q000097:blood* / Q000494:pharmacology
D018686:Anesthetics, Intravenous; D015742:Propofol