Quantitative EEG in assessment of anaesthetic depth: comparative study of methodology.

Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (EEG) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several EEG features. We have compared the performance of four techniques using tape-recorded data from 23 patients anaesthetized with either halothane or isoflurane using standardized regimens. The techniques were: (1) median frequency, (2) spectral edge frequency, (3) the cerebral function analysing monitor (CFAM1) and (4) a depth of anaesthesia monitor based on EEG pattern recognition (ADAM). Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and the limitations of single EEG measures, particularly with deeper anaesthesia producing a burst suppression pattern in the EEG. Pattern recognition techniques reduced these difficulties and appeared to be promising over a wide range of anaesthetic levels.

[1]  Reginald G. Bickford,et al.  Automatic electroencephalographic control of general anesthesia , 1950 .

[2]  Development of the CFM: the Cerebral Function Analysing Monitor (CFAM). , 1979, Annales de l'anesthesiologie francaise.

[3]  N. Ty Smithd,et al.  Monitoring Cerebral Function , 1980 .

[4]  H. Shapiro,et al.  Automated EEG processing for intraoperative monitoring: a comparison of techniques. , 1980, Anesthesiology.

[5]  W. Levy.  Intraoperative EEG Patterns: Implications for EEG Monitoring , 1984, Anesthesiology.

[6]  W J Levy,et al.  Effect of Epoch Length on Power Spectrum Analysis of the EEG , 1987, Anesthesiology.

[7]  H Schwilden,et al.  Closed‐loop Feedback Control of Methohexital Anesthesia by Quantitative EEG Analysis in Humans , 1987, Anesthesiology.

[8]  I. Rampil,et al.  Changes in EEG spectral edge frequency correlate with the hemodynamic response to laryngoscopy and intubation. , 1987, Anesthesiology.

[9]  H Schwilden,et al.  Quantitative EEG analysis during anaesthesia with isoflurane in nitrous oxide at 1.3 and 1.5 MAC. , 1987, British journal of anaesthesia.

[10]  D. Maynard,et al.  Monitoring Cerebral Function: Long-Term Monitoring of Eeg and Evoked Potentials , 1987 .

[11]  Carsten Thomsen,et al.  COMPUTERIZED MONITORING OF DEPTH OF ANAESTHESIA WITH ISOFLURANE , 1989 .

[12]  P V Cole,et al.  Quantitative EEG and brainstem auditory evoked potentials: comparison of isoflurane with halothane using the cerebral function analysing monitor. , 1990, British journal of anaesthesia.

[13]  J. Drummond,et al.  A comparison of median frequency, spectral edge frequency, a frequency band power ratio, total power, and dominance shift in the determination of depth of anesthesia , 1991, Acta anaesthesiologica Scandinavica.

[14]  A. Aitkenhead,et al.  Incidence of awareness with recall during general anaesthesia , 1991, Anaesthesia.

[15]  C. Thomsen,et al.  Assessment of anaesthetic depth by clustering analysis and autoregressive modelling of electroencephalograms. , 1991, Computer methods and programs in biomedicine.

[16]  J. Jones,et al.  Evaluation of the actions of general anaesthetics in the human brain. , 1992, General pharmacology.

[17]  R. Sandin,et al.  Awareness during total i.v. anaesthesia. , 1993, British journal of anaesthesia.

[18]  J. Schroeder,et al.  Quantitative EEG analysis during cardiac surgery in a case of spontaneous recall. , 1993, Electroencephalography and clinical neurophysiology.

[19]  M R Nuwer,et al.  Neuromonitoring during surgery. Report of an IFCN Committee. , 1993, Electroencephalography and clinical neurophysiology.

[20]  J G Jones,et al.  Perception and memory during general anaesthesia. , 1994, British journal of anaesthesia.