Meta-Analysis of the Efficacy and Safety of Ketamine on Postoperative Catheter-Related Bladder Discomfort

Objectives: We conducted meta-analysis to demonstrate the efficacy and safety of ketamine on postoperative catheter-related bladder discomfort (CRBD). Methods: A systematic search was performed through PubMed, Embase, and Cochrane Library to identify all randomized controlled trials that used ketamine in postoperative CRBD. This study was carried out by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We used RevMan version 5.3.0. to analyze the data. Results: Five RCTs involving 414 patients were included in the analysis. The incidence and severity of postoperative CRBD were assessed at 0, 1, 2, and 6 h. According to our results of meta-analysis, ketamine reduced the incidence of postoperative CRBD at 2 h (RR 0.39; 95% CI, 0.21–0.71; p = 0.002, I(2) = 40%) and 6 h (RR 0.29; 95% CI, 0.16–0.50; p < 0.0001, I(2) = 0%) significantly; however, there were no statistical differences at 0 h (RR 0.81; 95% CI, 0.35–1.88; p = 0.62, I(2) = 96%) and 1 h (RR 0.57; 95% CI, 0.13–2.54; p = 0.46, I(2) = 97%). In two studies, we compared the incidence of moderate-to-severe CRBD between groups according to the scaling system (none, mild, moderate, and severe), and data are presented as numbers. Patients in the ketamine group showed a significantly lower severity of CRBD than those in the placebo group at 1 h (RR 0.09; 95% CI, 0.03–0.31; p = 0.0001) and 2 h (RR 0.06; 95% CI, 0.01–0.44; p = 0.005). In contrast, there were no meaningful differences between the two groups in the severity of CRBD at 0 h (RR 0.18; p = 0.84) or 6 h (RR 0.20; 95% CI, 0.03–1.59; p = 0.13). There were no meaningful differences on the rate of adverse events between the ketamine group and control group, mainly including postoperative nausea and vomiting (RR 1.24; 95% CI, 0.89–1.72; p = 0.21), diplopia (RR 3.00; 95% CI, 0.48–18.67; p = 0.24), and hallucination (RR 3.00; 95% CI, 0.32–28.24; p = 0.34). Conclusion: Our meta-analysis demonstrated that a sub-hypnotic dose of ketamine administration can reduce the incidence and severity of postoperative CRBD without causing evident side effects.