Effects Of Dexmedetomidine On Hemodynamics And Postoperative Sleep In Elderly Patients Undergoing Gastrointestinal Surgery

Objectives:This study was designed to investigate the effect of dexmedetomidine of different dosage on intraoperative hemodynamics and postoperative sleep in elderly patients following elective gastrointestinal surgery.Methods:Twenty-four patients, ASAⅡorⅢ, aged between 65 and 80 years, undergoing open gastrointestinal surgery were randomly divided into three groups (n=8 in each group). In the second group, the patients were administered as a loading dose of dexmedetomidine 0.5 ug/kg over 10 minutes before the anesthesia induction. In the third group, the patients were administered as a loading dose of dexmedetomidine 0.5μg/kg over 10 minutes, followed by an infusion of 0.5～0.6μg/kg/hr until the maintenance dose was up to 1.5μg/kg. While those in the first group replace dexmedetomidine with normal saline infusion as Group III. Haemodynamics were monitered perioperatively. Preoperative and postoperative first three days (7am) blood samples were collected from all patients, and the melatonin concentration of the blood samples were measured by ELISA. Meanwhile AIS, MMSE tests were used to evaluate the sleep quality and cognition everyday.Results :①Groups were similar for clinical characters (P>0.05) .②he incidence of hypertension requiring treatment was significant lower in GroupⅢ(P＜0.05) while,the incidence of hypotension ,tachycardia (HR>100bmp) and severe bradycardia (HR<50bmp) were similar in three groups (P>0.05) .③he secretion of melatonin was reduced on the first three postoperative days(P＜0.05), and there were no significant differences in three groups (P>0.05) whereas GroupⅢhad lower mean AIS scores (P<0.05) on the first day after the surgery.④Intraoperative fentany consumption were lower in GroupⅡand GroupⅢ, and postoperative fentanyl consumption at identical pain scores were lower in GroupⅢ(P<0.05), whereas there was no significant difference between the other groups. The mean time to extubation were similar in three groups (P>0.05).⑤here were no significant differences with regard to mean scores of sedation, pain, nausea, and postoperative hospital stay in three groups.Conclutions:Dexmedetomidine, a total dose of 2μg/kg, provided better hemodynamics and better postoperative sleeping quality in elderly patients undergoing gastrointestinal surgery.