Effect Of Dexmedetomidine In Patient-controlled Intravenous Analgesia On Pain Attenuation After Total Hip Arthroplasty

Objective:To explore the efficacy and safe dose of dexmedetomidine combined with fentanyl and tramadol for patient-controlled intravenous analgesia after total hip arthroplasty.Methods:Eighty patients who received intravenous general anesthesia combined with suprainguinal fascia iliaca block for THA surgery in the First Affiliated Hospital of Guangxi Medical University were randomly divided into 4groups.Group D（1～3）:0.05mg,0.1mg,0.15mg dexmedetomidine combining with 0.5 mg fentanyl,500 mg tramadol and 10 mg tropisetron were used for PCIA.Group C:0.5 mg fentanyl,500 mg tramadol and 10 mg tropisetron were used for PCIA.PCIA was diluted to 150 ml with 0.9%normal saline.The PCIA was programmed to 3 ml/h background infusion（1g/h,2g/h and 3g/h dexmedetomidine）and deliver 3 ml per demand with a 30 min lockout interval.The visual analogue scores and Ramsay scores of the patients were recorded at30 min（T₁）,3 h（T₂）,6 h（T₃）,12 h（T₄）,24 h（T₅）and 48 h（T₆）after removal of endotracheal tube.The mean blood pressure,heart rate and respiratory rate were noted at T₀（before surgery）,T₁,T₂,T₃,T₄,T₅ and T₆.Sedation and analgesia scores were noted at T₁,T₂,T₃,T₄,T₅ and T₆.PCIA pump bolus outcomes,effective and ineffective pressing times were recorded at T₅ and T₆.The number and the time of patients who required additional rescue analgesics,ambulation and discharge time,opioid consumption,the incidence of adverse reactions such as skin pruritus,nausea and vomiting,and satisfaction score were evaluated as well.Results:（1）Analgesia scores（T₃～T₆）,effective pressing times and opioid consumption（T₅）in Group C were significantly higher than in Group D₁,D₂ and D₃（<0.05）.Opioid consumption（T₆）in Group C were significantly higher than in Group D₂（<0.05）.Ineffective pressing times（T₆）,rescue analgesics and the time of patients who required additional rescue analgesics in Group C were significantly higher than in Group D₁ and D₂（<0.05）.（2）The sedation scores in group D₃ were significantly higher than in Group C and D₂ at T₁（<0.05）.（3）The incidence of adverse drug reactions in group C was significantly higher than in Group D₁,D₂ and D₃（<0.05）.Patients in Group D₂ had significantly higher levels of satisfaction than patients in Group C（<0.05）.Conclusions:Dexmedetomidine（1～3g/h）combined with fentanyl and tramadol for patient-controlled intravenous analgesia after total hip arthroplasty significantly enhanced the analgesic effects and was devoid of untoward respiratory and hemodynamic changes.However,there was no evidence to prove that the analgesic effects of three doses of dexmedetomidine were different.According to the improvement of feelings and satisfaction,the PCIA with 2g/h dexmedetomidine maybe a better choice after THA.