ObjectiveTo compare the effects of ropivacaine and bupivacaine on urinary tract function in patients with thoracic epidural analgesia(TEA) by monitoring residual urine volume and maximum urine flow.

MethodsFifty patients undergoing elective open thoracic and abdominal surgery were selected and divided into group A(bupivacaine analgesic group) and group B(ropivacaine analgesic group) by random number table method, with 25 patients in each group.Urodynamic examination was performed in preoperative and TEA.The primary observation index was the difference of postoperative residual urine volume(PVR) before and after TEA, and the secondary observation index was the change of maximum urine flow between groups and within groups.

ResultsDuring TEA, PVR in both groups increased compared with the baseline value(P < 0.05), and PVR in group A was higher than that in group B(P < 0.01).The urine output in group A was higher than that in group B during TEA(P < 0.01).During TEA, the maximum urine flow and bladder contraction index in the two groups were decreased compared with the baseline value(P < 0.05), and which in group A was lower than that in group B(P < 0.01).There were no significant differences in baseline value, initial urine intention, strong urine intention, maximum bladder capacity and bladder compliance parameters between the two groups during TEA(P>0.05).

ConclusionsThe residual urine volume of ropivacaine for TEA is significantly lower than that of bupivacaine, which reflects that ropivacaine has little effect on detrusor function.