Effects of Subanesthetic Esketamine on Postoperative Sleep Quality Through EEG Analysis in Breast Cancer Patients: A
Yuening Zhan1, Yanmei Zhang1, Zhaohui Liu1
1Department of Anesthesiology, Cancer Hospital of Dalian University of Technology, Liaoning Cancer Hospital & Institute, Shenyang, Liaoning, People's Republic of China.
Background:
Postoperative sleep disturbance (POSD) is prevalent following breast cancer surgery, impairing postoperative recovery. However, effective interventions and underlying mechanisms remain unclear. This study aims to evaluate whether intravenous subanesthetic esketamine improves postoperative sleep quality and its association with electroencephalogram (EEG) frequency band changes in breast cancer patients.
Methods:
In this randomized, double-blind, placebo-controlled trial, patients undergoing breast cancer surgery received either intravenous esketamine (0.2 mg/kg induction, 0.4 mg/kg/h maintenance) or placebo during anesthesia. Both groups received intraoperative EEG monitoring. The primary outcome was POSD incidence at 24 hours assessed by the Pittsburgh Sleep Quality Index (PSQI). Secondary outcomes included PSQI scores at 72 hours, Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) scores, Visual Analog Scale (VAS) pain scores, and intraoperative EEG parameters.
Results:
POSD incidence was significantly reduced in the esketamine group compared with the control group (27.3% [16/58] vs 51.7% [30/58]; odds ratio, 0.36; 95% CI, 0.16-0.77; P = 0.014). Moreover, the esketamine group demonstrated significantly lower PSQI scores at both 24 hours (median [IQR], 2 [1-5] vs 4 [4-8]; P < 0.001) and 72 hours (1 [0-2.5] vs 3.5 [2.75-5]; P < 0.001). The esketamine group exhibited significantly higher intraoperative gamma-band relative power spectral density (mean [SD], 0.74 [0.25] vs 0.52 [0.18]; P < 0.001), which was independently associated with reduced POSD risk in multivariate analysis (odds ratio, 0.63; 95% CI, 0.40-0.97; P = 0.039).
Conclusion:
Subanesthetic esketamine significantly reduced the incidence of POSD and lowered PSQI scores. Importantly, esketamine was associated with enhanced intraoperative gamma-band EEG activity, which was independently associated with reduced POSD risk, suggesting that modulation of specific cortical oscillations may underlie its sleep-enhancing effects.
Trial Registration:
Chinese Clinical Trial Registry Identifier: ChiCTR2400092257.


