S-Ketamine Improves Slow Wave Sleep and the Associated Changes in Serum Protein Among Gynecological Abdominal Surgery Patients: A Randomized Controlled Trial

PURPOSE: This study aims to evaluate the effect of S-ketamine on slow wave sleep (SWS) and the related changes in serum protein in gynecological patients after open abdomen surgery. METHODS: This was a randomized controlled trial. One hundred gynecological patients undergoing open abdomen surgery were randomized into an S-ketamine group (group S) or placebo group (0.9% saline; group C). During operation, patients in group S received adjuvant S-ketamine infusion (0.2 mg·kg(−1)·h(−1)) while those in group C received 0.9% saline. All patients were connected to patient-controlled intravenous analgesia (PCIA) pump in the end of the surgery and the patients in group S with an additional S-ketamine in PCIA pump. Polysomnogram (PSG) was monitored during the next night after surgery with PCIA pump. Blood samples were collected for proteomic analysis at 6:00 AM after PSG monitoring. The primary outcome was the percentage of SWS (also known as stage 3 non-rapid eye movement sleep, stage N3) on the next night after surgery, and the secondary outcome was subjective sleep quality, pain scores, and the changes in serum proteomics. RESULTS: Complete polysomnogram recordings were obtained from 64 study participants (31 in group C and 33 in group S). The administration of S-ketamine infusion resulted in a significant increase in the percentage of SWS/N3 compared to the control group (group C, median (IQR [range]), 8.9 (6.3, 12.5); group S, median (IQR [range]), 15.6 (12.4, 18.8), P<0.001). However, subjective evaluations of sleep quality revealed no significant variances between the two groups. The protein affected by S-ketamine was primarily associated with posttranslational modification, protein turnover, carbohydrate transport, and metabolism. CONCLUSION: In patients undergoing open gynecological surgery, S-ketamine enhanced the percentage of objective sleep of SWS during the next night after surgery. Additionally, there were differences observed in serum protein levels between the two groups. TRIAL REGISTRATION: ChiCTR2200055180. Registered on 02/01/2022.