The Effect Of Different Doses Of Dexmedetomidine On Recovery From Intravenous Anesthesia Under The Guidance Of Entropy Index

Objective:To observe the effects of infusion of different doses of dexmedetomidine on the entropy index,recovery time and hemodynamic changes during the recovery period of total intravenous anesthesia,and to find an optimal dexmedetomidine Dosage.Methods:After the ethics review of this study was approved,ASA l-ll patients aged 20-60 years who were scheduled to undergo elective cholecystectomy in the Affiliated Hospital of Inner Mongolia University for Nationalities and met the inclusion criteria were allowed to participate in this study.The study was conducted after obtaining informed consent.A total of 120 patients were randomly divided into 30 in each in groups A,B,and C and dexmedetomidine was infused in the drug storehouse mode at doses of 0.5ug/kg/h,0.8ug/kg/h,1.0 ug/kg/h respectively.The control group D was injected with normal saline.Premedication for all patients:Changtuoning 0.5 mg Ⅳ.Dexmedetomidine infusion started two minutes before induction of general anesthesia and continued for 15 minutes.General anesthesia was induced by sufentanil 0.3ug/kg,propofol 3ug/ml plasma control infusion,and cisatracurium 0.16mg/kg.There were no significant differences in gender,weight,and height.The preoperative preparations for the four groups of patients were the same,such as fasting,allergy testing,and there was no difference in the implementation of general anesthesia,except for the changes in the dose of dexmedetomidine in the above experimental groups.Propofol and remifentanil infusions were used to maintain anesthesia and their doses were adjusted to maintain RE/SE and SPI values in the 40-60 range.The time T0 when the patient entered the operating room was recorded.Monitored and recorded patient’s heart rate(HR),blood pressure(Bp),SPI,state entropy(SE),response entropy(RE),before intubation(T1),after intubation(T2),and 1 minute after the start of surgery(T3),before extubation(T4),1 minute after extubation(T5),and 5 minutes after extubation(T6).The eye-opening time(Te)and extubation time(Te)were recorded,and the Ramsey sedation score(RASS)was used to judge the quality of recovery from general anesthesia.The collected data were grouped and analyzed using SPSS 20.0.Result:(1)The effect of DEX on RE/SE was dose-dependent.RE at T1 was statistically significant in all four groups,p<0.05.However,in all four groups,SE was not statistically significant at T1,>0.05.The RE and SE of the four groups were statistically significant at T3 and T6,p<0.05.SPI was statistically significant in all four groups at T1,T2,T3 and T6,p<0.05.DEX dose dependently affected SPI in all three DEX groups at T1,T2,T3,and T6.This suggests that DEX has analgesicsparing effect.SPI decreased rapidly during anesthesia induction the DEX group.(2)All four groups had no significant difference in RASS at T5,p>0.1.All groups had significant difference in RASS at T6,p<0.1.There was a statistically significance in RASS in group A,B and D at T6,p<0.05.There was no significant difference in RASS in group A and D at T6,p>0.05.(3)At T1 and T2,HR and MAP were slightly higher in all four groups than at T3.DEX affected the cardiovascular system in a dose-dependent manner,as HR and MAP were lower in the DEX group than in the control group D at T3.HR and MAP did not differ significantly among all groups at T4,T5 and T6.Conclusion:Under guidance of entropy index,iv DEX 0.5ug/kg/h infusion for 15min has advantage of reducing induction and intubation time,has minimal impact on hemodynamics and recovery.