Table 1.
Summary of the characteristics of the included studies.
| Study | Surgery type | Sample size | Study group | Strategy of esketamine | Age | ASA (I/II/III/IV) | Assessment | Assessment duration (d) | Incidence of POD (%) | Endpoint priority | Effect of esketamine on POD |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Zha J, 2025 (14) | Gastrointestinal tumor surgery | 100 | Esketamine VS normal saline | 0.25 mg/kg upon anesthesia induction | Elderly | I + II/III:44/6 VS 44/6 | 3D-CAM | 7 | 24.0 VS 48.0 | primary | positive |
| Xiong X, 2024 (15) | Heart valve replacement | 112 | Esketamine VS normal saline | Single dose of 0.25 mg/kg before anesthesia induction | Adult | 0/14/42/0 VS 0/13/43/0 | CAM-ICU/3D-CAM | 7 | 23.2 VS 42.9 | primary | positive |
| Zhang Y, 2024 (16) | Noncardiac surgery | 426 | Esketamine VS normal saline | Single dose 0.2 mg/kg before anesthesia induction | Elderly | / | 3D-CAM | 7 | 54.9 VS 53.1 | primary | No effect |
| Ma CB, 2024 (17) | TKA and THA | 260 | Esketamine VS normal saline | 0.20 mg/kg loading, 0.125 mg/kg/h infusion, 0.5 mg/kg for postoperative analgesia | Elderly | 0/96/34/0 VS 0/101/29/0 | 3D-CAM | 3 | 8.5 VS 10.8 | primary | no effect |
| Xie J, 2025 (24) | Esophageal cancer surgery | 202 | Esketamine VS normal saline | Continue intravenous esketamine 0.015 mg/kg/h for 48 h postoperatively. | Adult | 22/77/0/0 VS 27/76/0/0 | ICDSC | / | 16.2 VS 13.6 | Secondary | No effect |
| Xi L, 2025 (25) | Heart valve replacement | 78 | Esketamine+remimazolam VS dexmedetomidine | 0.5 mg/kg before operation and maintained at 0.5 mg/kg/h intraoperatively | Adult | 0/14/25/0 VS 0/11/28/0 | CAM | 3 | 12.82 VS 33.3 | Secondary | positive |
| Ju LY, 2025 (26) | OPCABG | 134 | Esketamine VS normal saline | 0.25 mg/kg/h intraoperatively | Adult | 0/0/12/55 VS 0/0/16/51 | CAM-ICU / 3D-CAM | 7 | 13.4 VS 28.4 | primary | No effect |
| Hua H, 2025 (27) | THA | 114 | Esketamine+dexmedetomidine opioids free anesthesia VS balanced anesthesia with opioids | 0.35 mg/kg at induction and 0.2 mg/kg/h at maintenance | Elderly | 0/35/22/0 VS 0/42/15/0 | CAM-CR | 3 | 5.0 VS 17.0 | primary | positive |
| Hu S, 2025 (28) | Lumbar fusion surgery | 78 | Esketamine VS normal saline | Single dose of 0.25 mg/kg after anesthesia induction | Elderly | 0/32/7/0 VS 0/30/9/0 | CAM | 3 | 15.0 VS 44.0 | Secondary | positive |
| Fu H, 2025 (29) | Lung cancer surgery | 106 | Esketamine VS normal saline | 0.25 mg/kg during induction and 0.1 mg/kg/h during maintenance for 30 min | Elderly | 0/22/31/0 VS 0/26/27/0 | CAM | 3 | 3.8 VS 15.1 | primary | positive |
| Zhang CL, 2024 (30) | Lung cancer surgery | 163 | Esketamine+dexmedetomidine VS dexmedetomidine | 0.25 mg/kg esketamine during anesthesia induction,continuous infusion 0.125 mg/kg/h until 30 min before the end of surgery | Elderly | 0/23/59/0 VS 0/19/62/0 | 3D-CAM | 7 | 14.6 vs. 30.9 | primary | positive |
| Ye Q, 2024 (31) | Hip surgery | 121 | Esketamine+dexme-detomidine opioids free group VS balanced anesthesia with opioids | Esketamine 0.5 mg/kg during induction and 0.25 mg/kg/h during maintenance | Elderly | 0/44/16/0 VS 0/37/24/0 | CAM | 2 | 11.7 VS 4.8 | Secondary | No effect |
| Wang H, 2024 (32) | Breast cancer surgery | 64 | Esketamine VS normal saline | single dose of 0.2 mg/kg after anesthesia induction | Adult | / | / | 1 | 0 VS 0 | Secondary | No effect |
| Lu Y, 2024 (33) | Thoracic surgery | 94 | Esketamine VS dexmedetomidine | 0.5 mg/kg 20 min after anesthesia induction | Elderly | 14/19/14/0 VS 12/21/14/0 | CAM | / | 4.3 VS 19.2 | Secondary | positive |
| Liu J, 2024 (34) | Gastrointestinal surgery | 60 | Esketamine+sufenta-nil VS sufentanil in PCIA | 1 mg/kg in PCIA pump | elderly | / | CAM | 3 | 13. VS 40.0 | Secondary | positive |
| Li N, 2024 (35) | Breast cancer surgery | 120 | Esketamine VS sufentanil | 0.30 mg/kg loading,0.25 mg/kg/h infusion,100 mg for postoperative analgesia | Adult | 41/19/0/0 VS 40/20/0/0 | / | 2 | 5.0 VS 6.7 | Secondary | no effect |
| Jing Z, 2024 (36) | Gastrointestinal tumor surgery | 87 | Esketamine VS normal saline | Single dose of 0.25 mg/kg and 0.1 mg/kg/h infusion | Elderly | 0/35/9/0 VS 0/34/9/0 | CAM | 3 | 2.3 VS 11.6 | Secondary | No effect |
| Huang C,2024 (37) | Orthopedic, urologic and major abdominal surgeries | 209 | Esketamine VS normal saline | 0.5 mg/kg 10 min after induction and 2 mg/kg for PCIA | Elderly | 12/174/27 VS 8/166/30 | CAM | 5 | 12.1 VS 10.9 | primary | No effect |
| Ma J, 2023 (38) | Gastrointestinal tumors surgery | 62 | Esketamine VS normal saline | 0.25 mg/kg loading and 0.125 mg/kg/h infusions | elderly | 0/25/6/0 VS 0/24/7/0 | CAM-ICU | 3 | 9.7 VS 12.9 | Secondary | No effect |
| Liu T, 2023 (39) | Gynecological surgery | 39 | Esketamine VS normal saline | 0.125 mg/kg 30 min intraoperatively | Adult | 3/17/0/0 VS 1/18/0/0 | CAM-ICU | 1 | 0 VS 0 | Secondary | No effect |
| Gan SL, 2023 (40) | Lung cancer surgery | 151 | Esketamine VS normal saline | 0.1 mg/kg loading, 0.1 mg/kg/h infusion, 1 mg/ kg in PCIA | Adult | 35/42/1 VS 32/45/1 | CAM/CAM-ICU | / | 0 VS 0 | Secondary | No effect |
| Li J, 2022 (41) | TKA | 80 | Esketamine VS normal saline | 0.2 mg/kg during induction | elderly | 0/36/4/0 VS 0/35/5/0 | CAM | 3 | 0 VS 2.5 | Secondary | No effect |
TKA, Total knee arthroplasty; THA, Total hip arthroplasty; OPCABG, Off-pump coronary artery bypass grafting; PCIA, Patient controlled intravenous analgesia; ICDSC, Intensive Care Delirium Screening Checklist; CAM-CR, Chinese Revised Delirium Diagnostic Scale; 3D-CAM, 3-min Diagnostic Confusion Assessment Method; CAM, Confusion Assessment Method; CAM-ICU, Confusion Assessment Method for the Intensive Care Unit.