Effect of dexmedetomidine sedation on perioperative hemodynamics and heart rate variability in the aged patients with cataract operation

Objective To investigate the effect of dexmedetomidine sedation on perioperative hemodynamics and heart rate variability (HRV) in the aged patients with cataract operation.Methods Fifty aged patients with cataract who accepted phacoemulsification operation in local anesthesia,were divided into experiment group(dexmedetomidine group) and control group (0.9％ sodium chloride group) by random digits table method with 25 cases each.The experiment group was given local anesthesia,after dexmedetomidine load at 0.5 μg/kg intravenous infusion,dexmedetomidine continuous pumping [0.2-0.3 μg/ (kg ·h)] to maintain the depth of anesthesia.The control group was given the same dose 0.9％ sodium chloride intravenous infusion.Local anesthesia method:2％ lidocaine and 0.75％ bupivacaine 3 ml mixing for retrobulbar anesthesia.The changes of HRV and hemodynamics in the 2 groups before operation (T0),beginning operation (T1),perioperative10min (T2),perioperative30min (T3),postoperative (T4) were recorded,and hemodynamies was analyzed.Results The normalized units of low frequency (LFnu) and low frequency (LF)/high frequency (HF) at T1,T2,T3 in control group were significantly higher than those at T0 [(73.9 ± 9.2)％,(74.5 ± 9.0)％,(75.8 ± 8.5)％ vs.(61.3 ± 7.5)％ and 2.4 ± 1.1,2.6 ± 1.3,2.7 ± 0.9 vs.1.6 ± 0.5],total frequency power (TP) was significantly lower than that at T0 [(1372 ± 419),(915 ± 243),(1389 ± 142) Hz vs.(2351 ± 608) Hz],there were statistical differences (P ＜ 0.05).The LFnu and LF/HF at T1,T2,T3 in experiment group were higher than those at T0,but there were no statistical differences (P ＞0.05).The TP at T1,T2,T3 in experiment group was significantly lower than that at T0 [(1458 ± 325),(983 ±272),(1497 ± 210) Hz vs.(2235 ± 513) Hz],there was statistical difference (P ＜ 0.05).There was no statistical difference in normalized units of HF at all time points between the 2 groups (P ＞ 0.05).The LFnu,LF/HF and TP at T1,T2,T3 in experiment group were better than those in control group,there were statistical differences (P ＜ 0.05).The fluctuation of hemodynamics in experiment group was significantly lower than that in control group,there was statistical difference (P ＜ 0.05).Conclusion Dexmedetomidine sedation little effects on HRV during perioperative period in aged patients with cataract operation,can significantly reduce the influence of operation stimulation on autonomic nervous system and hemodynamics. Key words: Heart rate;  Dexmedetomidine;  Aged;  Cataract