The Effect of Intraoperative Infusion of Different Doses of Esketamine on the Quality of Recovery in Elderly Patients Undergoing Knee Arthroplasty

Objective: This study aimed to investigate the effect of intraoperative intravenous infusion of different doses of esketamine on the quality of postoperative recovery in elderly patients undergoing knee arthroplasty. Methods: This single-center double-blind controlled trial included 132 elderly patients, who were randomly assigned to four groups. Patients in groups K1, K2, and K3 received an intraoperative intravenous infusion of esketamine (0.1, 0.2, and 0.3 mg/kg) respectively. Patients in the control group (C) received a saline infusion. After surgery, all patients received a patient-controlled intravenous analgesia with sufentanil 2 μg/kg and tropisetron 6 mg, which was activated since pain intensity reached or exceeded 4 on 10. Rescue analgesia was achieved with additional intravenous infusions of 50 mg of flurbiprofen axetil. The primary outcome was the quality of recovery assessed by the QoR-40 score on postoperative day 1 (POD1). Secondary outcomes included the components of the QoR-40, the QoR-40 score on POD2 and 7, pain intensity, rescue analgesic used and the Athens Insomnia Scale (AIS) scores on POD 1, 2 and 7. Results: The QoR-40 score on POD1 was dose-dependently increased by esketamine, with a significant difference between groups K3 and K2 vs. K1 ( P < 0.0001, P =0.024) and C ( P < 0.0001, P =0.001), and between groups K3 vs. K2 ( P =0.001) Only a nonsignificant trend was observed between groups K1 and C. A similar and dose-dependent effect was observed on emotion state and psychological support (improved), and on pain, analgesic consumption and insomnia (reduced), both at POD1 and 2. No longer effect was observed at POD7. Conclusion: Intraoperative intravenous infusion of esketamine at doses of 0.2 mg/kg/h and 0.3 mg/kg/h improved the quality of recovery on POD1 in elderly patients undergoing knee arthroplasty. The 0.3 mg/kg/h dose of esketamine had the strongest effect, without apparent tolerance issues. Keywords: esketamine, quality of recovery, arthroplasty, elderly patients