Abstract Objective：To observe the clinical effect of Dexmedetomidine for elderly patients undergoing total hip replacement.Method：60 elderly patients with total hip replacement were selected and randomly divided into 3 groups，20 cases in each group.Patients in group A received a 4 μg/mL Dexmedetomidine intravenous infusion of 10 min，maintaining 0.2 g/（kg·h）； patients in group B received a 4 μg/mL Dexmedetomidine intravenous infusion of 10 min，maintaining 0.4 g/（kg·h）； patients in group C received a 0.9% Sodium Chloride Solution.The he heart rate（ HR）， mean arterial pressure（ MAP） and oxygen saturation（ SpO2） level of 3 groups were observed and recorded before and after anesthesia， intraoperative and postoperative.The propofol dosage and awake time of 3 groups were recorded， respectively. At the same time， pain degree was measured by using visual analogue scoring system（ VAS）.The incidence of adverse reaction were observed after operation.Result：After anesthesia， the patients in the B group SPO2 was significantly lower than that of A group and C group， the difference was statistically significant（ P<0.05）.The patients in the B group of propofol dosage is lower than that of A group and C group（P<0.05）. The patients in the A group VAS were lower than those of B group and C group（P<0.05）. Hypoxemia in patients in the B group were higher than A group and C group（P<0.05）. Conclusion：Dexmedetomidine for elderly total hip replacement， sedative effect significantly， the respiratory inhibition is lighter and less adverse reaction.
