Effects of dexmedetomidine on heart rate variability in patients undergoing laparoscopic cholecystectomy

Objective To evaluate effects of dexmedetomidine on heart rate variability(HRV) in patients with laparoscopic cholecystectomy.Methods A prospective,randomized,double-blind and placebo controlled clinical protocol was used in this study.sixty patients(ASA Ⅰ or Ⅱ) undergoing laparoscopic cholecystectomy were randomly allocated to three groups with 20patients in each.When the induction of anesthesia started,dexmedetomidine 0.4μg/kg(group Dex1),0.5μg/ kg(group Dex2)or the same volume of normal saline(group NS)was infused intravenously within 10 min at induction.All patients received the same method of induction and the maintenance of anesthesia.SBP,HR,low frequency power(LF),high frequency power(HF),LF/HF ratio and total frequency power(TF)were recorded before induction of anesthesia(T0),1 min after pneumoperitoneum(T1),5 min after pneumoperitoneum(T2),10 min after pneumoperitoneum(T3),20 min after pneumoperitoneum(T4)and lifting of pneumoperitoneum after 5 min(T5). Results Compared with baseline,the LF increased at T4in group Dex1,and increased at T2and T4 in group Dex2.The LF was lower at T5in group Dex1(P0.05).The HF and TF increased at T3 and T4in group Dex1,and increased at T2-T4in group Dex2(P0.05).The LF/HF was higher at T1in group NS.The LF/HF was lower at T3,T4in group Dex1and decreased at T3in group Dex2(P0.05).Conclusion Infusion of dexmedetomidine during anesthesia induction can not only inhibit stress reaction of laparoscopic cholecystectomy,stabilize the hemodynamics,but also improve the equilibrium state of sympathetic and vagal activity.