Effect of sedation with regional anesthesia with dexmedetomidine on postoperative cognitive function in elderly patients with diabetes mellitus

Objective To evaluate the effect of sedation with regional anesthesia with dexmedetomidine on postoperative cognitive function in elderly patients with diabetes mellitus. Methods A total of 180 elderly patients of either sex with diabetes foot, aged 65-80 yr, weighing 45-90 kg, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with preoperative Mini-Mental State Examination score>24, undergoing elective debridement, were divided into 2 groups(n=90 each)using a random number table: sedation with dexmedetomidine group(group D)and routine sedation control group(group C). Lumbar plexus block and sciatic nerve block were performed, after the reliable efficacy was achieved, dexmedetomidine was intravenously infused in a dose of 0.5 μg/kg for 10 min followed by an infusion of 0.5 μg·kg-1·h-1 until the end of surgery.Midazolam 0.02-0.04 mg/kg was intravenously injected and midazolam 1 mg was injected intermittently during operation in group C. Ramsay sedation scores were maintained between 2 and 4.At 30 min before surgery(T1), 1 h after the beginning of surgery(T2), at the end of surgery(T3), 6 h after the end of surgery(T4), and 24 h after the end of surgery(T5), venous blood samples were collected for determination of the level of blood glucose and plasma cortisol(Cor)concentrations.Mini-Mental State Examination scores were assessed at 1 day before surgery and 1 and 3 days after surgery, and the occurrence of postoperative cognitive dysfunction was recorded in a short time period after operation. Results Compared with the baseline at T1, the level of blood glucose at T2-5 and plasma Cor concentrations at T3, 4 were significantly increased in group C, and plasma Cor concentrations were significantly increased at T3, 4(P 0.05). Compared with group C, the level of blood glucose at T3-5 and plasma Cor concentrations at T3, 4 were significantly decreased, Mini-Mental State Examination scores were increased at 1 and 3 days after operation, and the incidence of postoperative cognitive dysfunction in a short time period after operation was decreased in group D(P<0.05). Conclusion Sedation with regional anesthesia with dexmedetomidine can improve postoperative cognitive function in elderly patients with diabetes mellitus. Key words: Dexmedetomidine; Aged; Diabetes mellitus; Cognition; Postoperative complications