Subanaesthetic dose of esketamine during induction delays anaesthesia recovery a randomized, double-blind clinical trial

Background: Esketamine is an antagonist of the N-methyl-D-aspartate receptor (NMDA receptor) that is widely used for multimodal analgesia. In addition to analgesia, sedation is another important effect of esketamine. However, data are limited regarding the sedation effect of esketamine during general anaesthesia. The objective of this study was to determine whether sedation with a subanaesthetic does of esketamine affects anaesthesia recovery. Methods: Fifty patients, ASA I to II patient scheduled to laparoscopic cholecystectomy, were randomly assigned to receive a single bolus of esketamine 0.2 mg kg-1 (esketamine group) or placebo (control group). Propofol, sufentanil and rocuronium were used during total intravenous anaesthesia. The patients'time of recovery from anaesthesia, postoperative pain, postoperative nausea and vomiting, and postoperative agitation were analysed. Results: Data from 47 patients were analysed. The average time of anaesthetic recovery was 22.04 +/- 1.48 min in the esketamine group(n = 23) and 17.54 +/- 1.46 min in the control group(n = 24). The recovery time was significantly longer in the esketamine group. Postoperative pain in the PACU was lower in the esketamine group (NRS score range 0-2) than in the control group (NRS score range 0-3). There were no differences in postoperative nausea and vomiting, and postoperative agitation. Conclusion: Subanaesthetic doses of esketamine can reduce postoperative pain in the PACU but delay the aesthetic recovery during the laparoscopic cholecystectomy, without affecting postoperative nausea and vomiting, and post-operative agitation.