CLINICAL UTILITY OF EEG PARAMETERS TO PREDICT LOSS OF CONSCIOUSNESS AND RESPONSE TO SKIN INCISION DURING TOTAL INTRAVENOUS ANESTHESIA

We studied 30 female patients undergoing elective surgery, to assess t he reliability of electroencephalogram spectral edge frequency and med ian frequency to predict loss of consciousness and movement in respons e to skin incision during total intravenous anaesthesia. Each patient received a different combination of propofol (1, 2, 3, 4, 5 or 6 mu g. ml(-1)) and sufentanil (0.1, 0.2, 0.3, 0.5 or 1.0 ng.ml(-1)) target co ncentrations for induction of anaesthesia using target controlled infu sions, assigned randomly. In a logistic regression model, spectral edg e frequency was a significant determinant of both loss of consciousnes s (p = 0.0006) and movement to skin incision (p = 0.0044), whereas for median frequency no significant prediction model could be established . The probabilities of 50% and 95% no response for spectral edge frequ ency were 13.4 Hz and 6.8 Hz, respectively The variability of the data limited the predictive value, so that spectral edge frequency was a p oor predictor and median frequency was no predictor of response in the individual patient during total intravenous propofol/sufentanil anaes thesia.