Effect of an Intravenous Dexamethasone Added to Caudal Local Anesthetics to Improve Postoperative Pain: A Systematic Review and Meta-analysis With Trial Sequential Analysis

BACKGROUND: Caudal anesthesia has been used for postoperative pain control in pediatric surgical patients, but the duration of the analgesic effect is occasionally unsatisfactory. Intravenous steroids have been shown to be effective for postsurgical pain management after certain surgeries. The aim of this meta-analysis with trial sequential analysis (TSA) was to evaluate the analgesic effect of steroids in patients administered with caudal anesthesia. METHODS: This study was a systematic review and meta-analysis. A search of published literature was conducted in the MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials databases and in trial registration sites. Randomized controlled trials that compared intravenous steroids with a placebo in pediatric patients who had received caudal anesthesia for surgery were included in the study. The primary outcomes from the present meta-analysis were the analgesic duration and the number of patients who required rescue analgesics. The analgesic duration and incidence of rescue use were summarized using mean difference or risk ratio with a 97.5% confidence interval (CI), respectively. If the 97.5% CI of the mean difference or risk ratio included a value of 0 or 1, respectively, we considered the difference not to be significant. We used the random effects model to combine the results. Heterogeneity was quantified with the I2 statistic. The quality of the trials was evaluated using the Cochrane methodology. Moreover, a TSA with a risk of type 1 error of 2.5% and power of 90% was performed. We established the minimum clinically meaningful difference of analgesic duration as 3 hours. The target sample size for meta-analysis was also calculated in the TSA. We also assessed adverse events. RESULTS: Six trials with 424 patients were included; 211 patients received intravenous steroids. All trials compared dexamethasone of at least 0.5 mg/kg dose with a placebo. Dexamethasone prolonged the duration of caudal analgesia (mean difference, 244 minutes; 97.5% CI, 188–300). Heterogeneity was considerable with an I2 value of 94.8%. Quality of evidence was very low. The TSA suggested that only 17.0% of the target sample size had been reached, but the cumulative Z score crossed the trial sequential monitoring boundary to indicate a benefit. Rescue use was reported in 4 studies with 260 patients. Rescue use was not significantly reduced in the dexamethasone group (risk ratio, 0.53; 97.5% CI, 0.09–3.30; I2, 98.7%). No increase in adverse events was reported. CONCLUSIONS: Intravenous dexamethasone prolongs the analgesic duration of caudal anesthesia. Trials to investigate the effectiveness of a lower dose of the dexamethasone in prolonging analgesic effects would be of interest. Further trials with a low risk of bias are necessary.

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