The effect of perioperative dexmedetomidine on postoperative delirium in adult patients undergoing cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis of randomized controlled trials.

Background: Dexmedetomidine is considered to have neuroprotective effects and may reduce postoperative delirium in both cardiac and major non-cardiac surgeries. Compared with non-cardiac surgery, the delirium incidence is extremely high after cardiac surgery, which could be caused by neuroinflammation induced by surgical stress and CPB. Thus, it is essential to explore the potential benefits of dexmedetomidine on the incidence of delirium in cardiac surgery under CPB.

Methods: Randomized controlled trials studying the effect of perioperative dexmedetomidine on the delirium incidence in adult patients undergoing cardiac surgery with CPB were considered to be eligible. Data collection was conducted by two reviewers independently. The pre-specified outcome of interest is delirium incidence. RoB 2 was used to perform risk of bias assessment by two reviewers independently. The random effects model and Mantel-Haenszel statistical method were selected to pool effect sizes for each study.

Results: PubMed, Embase, Cochrane Library, and Web of Science were systematically searched from inception to June 28, 2023. Sixteen studies including 3381 participants were included in our systematic review and meta-analysis. Perioperative dexmedetomidine reduced the incidence of postoperative delirium in patients undergoing cardiac surgery with CPB compared with the other sedatives, placebo, or normal saline (RR 0.57; 95% CI 0.41-0.79; P = 0.0009; I = 61%).

Conclusions: Perioperative administration of dexmedetomidine could reduce the postoperative delirium occurrence in adult patients undergoing cardiac surgery with CPB. However, there is relatively significant heterogeneity among the studies. And the included studies comprise many early-stage small sample trials, which may lead to an overestimation of the beneficial effects. It is necessary to design the large-scale RCTs to further confirm the potential benefits of dexmedetomidine in cardiac surgery with CPB.

Registration Number: CRD42023452410.