Objective:To compare the analgesic and side effects of patient-controlled intravenous analgesia (PCIA) among different doses of buprenorphine and tramadol.Methods:One hundred and twenty patients were randomly divided into three groups(Ⅰ

Ⅱ

Ⅲ

each group n =40).Patient-controlled intravenous analgesia(PCIA) was set with three solutions:In group Ⅰ the patients received PCIA with 0.6mg of buprenorphine

400mg of tramadol

2.5mg of droperidol with 0.9%N.S 47ml/60ml.In group Ⅱ the patients received PCIA with 0.9mg of buprenorphine

400mg of tramadol

2.5mg of droperidol with 0.9%N.S 45ml/60.In group Ⅲ the patients received PCIA with 0.6mg of buprenorphine

600mg of tramadol

2.5mg of droperidol with 0.9%N.S 43ml/60ml.The loading doses were 3ml

bolus dose 1ml

background infusion 0.010～0.015ml/(kg·h)

and lock-out time 10min.BP

HR

RR

SpO 2 and side effects (such as nausea

vomiting and dizziness)were monitored.The clinical effects were assessed by VAS score of pain and the number of PCIA pump by the patients.Results:All three solutions cauld provide better analgesia and patient satisfaction( P >0.05).All groups developed no excessive sedation and respiratory depression.Postoperative nausea

vomiting

dizziness and sweating were significantly less in group Ⅰ than in group Ⅱ and Ⅲ( P >0.05).Conclusion:Analgesic effects on PCIA with three mixtures of different doses of buprenorphine and tramadol were satisfactory.Group Ⅰ shows the lower rate of side effects and the dose is preferred in clinical use for PCIA.