We studied 30 male patients in the early postoperative period to assess the efficacy, safety and feasibility of a patient-demand, target-controlled infusion (TCI) of remifentanil. All patients received the same TCI-based propofol-remifentanil anaesthetic for elective orthopaedic surgery. At the end of surgery, infusion of remifentanil was reduced progressively until patients were breathing spontaneously. After extubation and transfer to the post-anaesthesia care unit, patients were given control of a hand-set and were able to increase the target remifentanil blood concentration by increments of 0.2 ng ml-1. If there were no demands, the TCI controller automatically reduced the target concentration. Pain scores, sedation level, ventilatory frequency, oxygen saturation and nausea were assessed. Mean time to onset of satisfactory analgesia (VAS < or = 3, out of 10) was 18.9 (95% confidence interval (Cl) 15.8-21.9) min at a mean target remifentanil concentration of 2.02 (Cl 1.87-2.16) ng ml-1. There were no episodes of hypoxaemia and the lowest ventilatory frequency was 9 bpm. Nausea occurred in 26.6% of patients and 10% vomited. The majority of patients were only slightly sedated. These results imply an effective tool without respiratory side effects in the early postoperative period after anaesthesia using remifentanil as the analgesic component.

This prospective study shows that a ST-segment depression of 0.1 mV or more in the exercise electrocardiogram is an independent predictor of perioperative cardiac complications.

SummaryWe studied 30 female patients undergoing elective surgery, to assess the reliability of electroencephalogram spectral edge frequency and median frequency to predict loss of consciousness and movement in response to skin incision during total intravenous anaesthesia. Each patient received a different combination of propofol (1, 2, 3, 4, 5 or 6 mg.ml ¹1 ) and sufentanil (0.1, 0.2, 0.3, 0.5 or 1.0 ng.ml ¹1 ) target concentrations for induction of anaesthesia using target controlled infusions, assigned randomly. In a logistic regression model, spectral edge frequency was a significant determinant of both loss of consciousness (p ¼ 0.0006) and movement to skin incision (p ¼ 0.0044), whereas for median frequency no significant prediction model could be established. The probabilities of 50% and 95% no response for spectral edge frequency 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 poor predictor and median frequency was no predictor of response in the individual patient during total intravenous propofol/sufentanil anaesthesia.

Etomidate-induced suppression of cortisol biosynthesis is a result of a blockade of 11-beta-hydroxylation in the adrenal gland, mediated by the imidazol radical of etomidate. Since the generation of steroids requires reductive and energy rich equivalents, the present study examined whether supplementation with ascorbic acid or xylitol, a major source of NADPH, could attenuate adrenal suppression by etomidate in human subjects by promoting the turnover rate of 11-beta-hydroxylase. During continuous etomidate/alfentanil anaesthesia for pelviscopic surgery 30 female patients received either Ringer's lactate, xylitol (0.25 g kg-1 h-1) or ascorbic acid (0.5 g h-1) intravenously (i.v.). The plasma concentrations of cortisol, aldosterone and dehydroepiandrosterone (DHEA) were recorded for 5 h after end of surgery and a stimulation with synthetic ACTH was performed. The results showed no evidence of a clinically relevant attenuating effect of ascorbic acid or xylitol on etomidate-induced adrenocortical suppression. However, the observed suppression of cortisol levels was not enough to allow an attenuating affect to be measured.

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