Comparison Of Patient-controlled-analgesia And Thoracic Paravertebral Block For Pain Relief After Thoracotomy

Objective To compare the efficacy of patient-controlled-analgesia (PCA) with intravenous morphine and thoracic paravertebral block (TPVB) with ropivacaine assisted with system analgesia. Methods41patients (Jan19th to May25th,2009) experienced unilateral thoracotomy were randomly devided into3groups to receive intravenous morphine analgesia (Group P, n=15), continuous infusion of0.2%ropivacaine in a thoracic paravertebral catheter at a constant rate (Group T) of0.1ml·kg-1·h-1(Group T1, n=14) or6ml/h (Group T2, n=12). Systemic analgesics were taken as complement in group T. Visual analog scale (VAS) at rest, pulmonary function test, requirement of systemic analgesics and side effects were recorded during the first48hours postoperatively. Results There were no significant differences of mean VAS scores among group P, T1and T2in the first24hours postoperatively. FVC and FEV1and preserved lung function values were significantly improved in group T (p<0.05). Side effects were less frequent in group T. Group Tl and group T2had similar effect on pain relieve. The mean distribution of the somatic block in Group T1and T2are5.78and5.59dermatomes, respectively (p>0.05). Conclusions Continuous paravertebral ropivacaine0.2%infusion combined with systemic analgesics has similar effect on pain control but better lung function and less complications than PCA with intravenous morphine after thoracic surgery. A loading dose of10ml, with sequent rate of O.lml·kg-1·h-1or6ml/h infusion of ropivacaine had similar effect on pain relief, but there was a possible trend that the frontal method may bring a better outcome.