Effects of esketamine on postoperative sleep quality in elderly patients under general anesthesia: a systematic review and meta-analysis

Background Postoperative sleep disturbance (PSD) is a common disorder among elderly patients undergoing surgery and is associated with a higher risk of adverse outcomes. This meta-analysis investigated the effects of esketamine on postoperative sleep quality among elderly patients. Methods PubMed, Embase, The Cochrane Library, CNKI, and Wanfang databases were searched to identify randomized controlled trials (RCTs) comparing intravenous esketamine with control in elderly patients (≥ 60 years) undergoing elective surgery in general anesthesia. Sleep quality on postoperative day (POD) 1 was the primary outcome. Other outcomes included sleep quality at other time points, objective sleep parameters, pain, cognitive function, and adverse events. Results Seventeen RCTs involving 2587 patients were included. Regarding the primary outcome, esketamine significantly improved subjective sleep quality on POD 1 (SMD = -0.72; 95% CI, -1.10 to -0.34; I² = 93%), POD 2 (SMD = -1.40; 95% CI, -2.15 to -0.64; I² = 97%), and POD 7 (SMD = -0.38; 95% CI, -0.62 to -0.14; I² = 53%). Objective sleep measures on POD 1 revealed longer total sleep time, reduced sleep latency, and improved sleep efficiency. Esketamine also decreased pain intensity (SMD = -0.63; 95% CI, -0.88 to -0.38; I² = 70%) and improved MMSE scores (SMD = 0.65; 95% CI, 0.42 to 0.89; I² = 0%). Esketamine was associated with a lower risk of nausea or vomiting. No significant differences was observed between the two groups in terms of dizziness, while hypotension occurred less frequently with esketamine. Conclusions Among elderly surgical patients, perioperative esketamine was associated with improved postoperative sleep quality, reduced pain intensity, and a potential improvement in cognitive function, without a significant increase in the risk of major adverse events. However, high-quality RCTs are needed to confirm these findings and determine optimal dosing regimens. Of note, all 17 included trials were conducted in China, potentially limiting the generalizability of our findings to other populations.