Dexmedetomidine effect on delirium in elderly patients undergoing general anesthesia: A protocol for systematic review and meta-analysis

BACKGROUND: Delirium is a common postoperative complication. Many studies have found that dexmedetomidine is associated with a reduced incidence of postoperative delirium (POD). This meta-analysis aimed to analyze the effects of dexmedetomidine on POD incidence among elderly patients undergoing general anesthesia. METHODS: We searched 4 electronic databases (i.e., Pubmed, Embase, Cochrane, and Web of Science) from inception to November 30, 2020, for randomized controlled trials that evaluated the effects of dexmedetomidine in preventing the occurrence of POD in elderly patients (aged ≥60 years). The study protocol was registered in PROSPERO (CRD42020192114). RESULTS: 14 studies with 4173 patients showed that dexmedetomidine was significantly associated with a decreased POD incidence among elderly patients (relative risk [RR] = 0.58; 95% confidence interval [CI] = 0.44–0.76). The incidence of POD was significantly reduced in the noncardiac surgery group (RR 0.51; 95% CI 0.37–0.72), when dexmedetomidine was applied during the postoperative period (RR = 0.53; 95% CI = 0.40–0.70), and in patients received low-doses (RR = 0.54; 95% CI = 0.34–0.87) and normal-doses (RR = 0.59; 95% CI = 0.42–0.83). There were no significant differences in POD incidence in the cardiac surgery group (RR = 0.71; 95% CI = 0.45–1.11), and when dexmedetomidine was applied during the intra- (RR = 0.55; 95% CI = 0.29–1.01) or perioperative period (RR = 0.95; 95% CI = 0.64–1.40). CONCLUSIONS: Our meta-analysis suggests that dexmedetomidine may significantly reduce POD incidence in elderly noncardiac surgery patients and when applied during the postoperative period, in addition, both low- and normal-doses of dexmedetomidine may reduce POD incidence. However, its use in cardiac surgery patients and during the intra- or perioperative period may have no significant effects on POD incidence.