The effect of raw EEG implementation for assessing depth of anaesthesia on patient quality of recovery

BACKGROUND: Processed electroencephalography is widely used to assess depth of anaesthesia and to titrate anaesthetics, thereby increasing the quality of recovery. However, the processed electroencephalogram is influenced by technical, patient, and anaesthetic factors. Adding information from the frontal real-time raw electroencephalogram may help to overcome these limitations. OBJECTIVE: To assess the effect of a raw electroencephalogram tutorial and its intra-operative implementation versus standard care on postoperative quality of recovery and propofol consumption. DESIGN: Multicentre double-blind randomised controlled trial. SETTING: The trial was conducted at four tertiary centres in Switzerland. PATIENTS AND ANAESTHESIA PRACTITIONERS: We screened 534 adult patients undergoing in-hospital laparoscopies and 346 anaesthesia practitioners with at least 2 years of anaesthesia experience. We matched and randomised 232 pairs and analysed 209. The patients were 78% female. INTERVENTION: The anaesthesia practitioners assigned to the patients were randomised to a validated tutorial for assessing depth of anaesthesia with the raw electroencephalogram or to a no tutorial group. Monitoring included raw and processed electroencephalogram for patients allocated to the tutorial and only processed electroencephalogram for the no tutorial group. MAIN OUTCOME MEASURES: The primary outcome was quality of recovery on the first postoperative day measured with the QoR-15 score. The first secondary outcome was propofol consumption. Groups were compared with a two-sample t -test. RESULTS: We found no statistically significant difference between the tutorial and the no tutorial group with mean differences of -3.2 [95% confidence interval (CI), -8.8 to 2.5, P = 0.273] for QoR-15 score and 0.36 mg kg -1 h -1 (95% CI, -0.01 to 0.73, P = 0.055) for propofol consumption. CONCLUSION: A short tutorial on the raw electroencephalogram and its addition intra-operatively was not able to improve quality of recovery or reduce propofol consumption in middle-aged, largely female patients. A more in-depth tutorial applied to more vulnerable patients might have shown different results.