Abstract:

Abstract:Objective To observe the  changes of haemodynamics during peri-extubation period and analepsia process in patients with general anesthesia for t
otal hip replacement after treated with different doses of dexmedetomidine(DEX)，and to provide theoretical basis for its application in clinic.
Methods 80 ASA Ⅰ-Ⅱ patients undergoing total hip replacement with general anesthesia were randomly divided into control group， low，moderate and high doses of DEX groups(n=20).The patients in various groups were pumped with 0，0.5，1.5 and 2.5 μg? kg-1 DEX 30 min before the end of
 operation，and lasted for 10 min. The systolic blood pressure (SBP)，diastolic blood pressure (DBP) ，heart rate (HR)，myocardial oxygen consumption (MCO) of the patients in various groups before administration(T0)，before extubation(T1)， at extubation(T2)，30 min after extubation(T3) were recorded.The wake-up time(t1)， extubation time(t2)， and Observer’s Assessment of Alterness/Sedation Scores (OAA/S)at 30 min after operation(Ta)，35 min after operation(Tb)，and 40 min after operation(Tc) were also recorded.Results Compared with control group，at T2 and T3，there were no statistical differences of the SBP，DBP，HR and MCO in low dose of DEX  group（P>0.05）;the SBP，DBP，HR and MCO in  moderate and high doses of DEX groups
were descended significantly，there were statistically significant differences(P<0.05);but there was no statistical difference between DEX moderate and high d
ose groups（P>0.05）.Compared with control group，the extubation time(t1) and wake-up time(t2) in high dose of DEX  group were prolonged significantly，and there were statistical differences(P<0.05).Compared with control group， the OAA/S of the patients in  high dose  of DEX group was reduced significantly，and there was statistical difference(P<0.05);but there were no statistical differences among the other three groups（P>0.05）.Conclusion
1.5 μg.kg-1  DEX can stablize the haemodynamics indexes of the patients with general anesthesia during extubation，shorten the time of analepsia and e
xtubation，and sustain OAA/S.
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Key words:  , dexmedetomidine, general anesthesia, haemodynamics, analepsia