Effect of intraoperative dexmedetomidine infusion on delirium in adult patients following cardiac valve surgery: a protocol of a randomized, double-blinded, and placebo-controlled study

Background: Delirium is an acute status of brain dysfunction that commonly occurs in patients who have undergone cardiac surgery, and increases morbidity and mortality. It is associated with risk factors, such as older age, use of narcotics, cardiopulmonary bypass, and hypothermia. Dexmedetomidine infusion might exert a neuroprotective effect. However, the effect of perioperative administration of dexmedetomidine on the incidence of postoperative delirium (POD) in patients undergoing cardiac or non-cardiac surgery is yet controversial. The present study aimed to reveal the effect of intraoperative dexmedetomidine administration on the incidence of delirium in adult patients following cardiac surgery. Methods: This single-center, randomized, double-blinded, and placebo-controlled trial consisted of 652 patients randomly divided into two groups: dexmedetomidine and placebo. 0.6 mu g/kg dexmedetomidine will be infused 10 min after central vein catheterization, followed by a continuous infusion at a speed of 0.4 mu g/kg/h until the end of surgery in the dexmedetomidine group, while normal saline will be administered at the same rate in the placebo group. The primary outcome is the incidence of POD during the first 7 days post-surgery. The secondary outcomes include duration of mechanical ventilation after surgery, duration of stay in the intensive care unit and the hospital after surgery, incidence of hypotension during or after dexmedetomidine infusion, acute kidney injury and sudden arrhythmia during the hospital stay postoperatively, and all-cause mortality in 30 and 90 days after surgery, respectively. Discussion: This study was approved by the Ethics Committee of the Chinese Academy of Medical Sciences Fuwai Hospital on 6 March 2019 (2019-1180). The results will be disseminated at academic conferences and submitted to peer-reviewed publications. Either positive or negative results will provide guidance for clinical practice.