Effect of dexmedetomidine on postoperative cognitive function in elderly patients with fragile brain

Objective To evaluate the effect of dexmedetomidine on the postoperative cognitive function in the elderly patients with fragile brain. Methods One hundred and twenty elderly patients with fragile brain, aged 65-85 yr, weighing 50-80 kg, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with preoperative Mini-Mental State Examination score≥20, scheduled for elective gastroenteric surgical procedures, were randomly assigned to one of 2 groups(n=60 each)using a random number table: control group(group C)and dexmedetomidine group(group D). In group D, dexmedetomidine was intravenously infused in a loading dose of 0.4 μg/kg over 10 min before anesthesia induction, followed by an infusion of 0.4 μg·kg-1·h-1until 30 min before the end of surgery.While the equal volume of 0.9% nomal saline was given instead of dexmedetomidine in group C. Postoperative delirium was assessed within 3 days after operation using Confusion Assessment Method.Postoperative cognitive dysfunction was assessed at 7 days after operation using Mini-Mental State Examination. Results Compared with group C, the incidence of postoperative delirium was significantly decreased within 3 days after operation(P 0.05). Conclusion Dexmedetomidine can decrease the occurrence of postoperative delirium in the elderly patients with fragile brain. Key words: Dexmedetomidine; Delirium; Cognition disorders; Aged; Fragile brain