[Motor function during patient-controlled analgesia via a lumbar epidural catheter after major abdominal surgery. Ropivacaine-sufentanil vs. bupivacaine-sufentanil].

INTRODUCTION: The aim of the present study was to investigate postoperative motoric impairment during patient-controlled analgesia after major abdominal surgery with ropivacaine-sufentanil and bupivacaine-sufentanil via a lumbar epidural catheter.

METHODS: After approval of the local ethics committee, 40 patients scheduled for major lower abdominal surgery were randomly allocated to receive bupivacaine 0.25 % or ropivacaine 0.2 %, both with sufentanil 2 microgram/ml in a double blind manner. General anaesthesia (midazolam, etomidate, fentanyl, vecuronium, and desflurane in N2O/O2) and postoperative management of the patients were standardised. Postoperatively, the motoric function and ability for active early mobilisation was examined clinically (application of the Bromage scale, ability to leave the bed and ability to walk). Reduction of muscular force of the legs was measured postoperatively using a scale and compared with preoperative baseline values. To ensure a similar level of analgesia, a 10-cm visual analogue scale was applied at rest and while coughing.

RESULTS: The two groups did not differ with respect to the demographic data and postoperative levels of analgesia. Less reduction of motoric function at rest was observed in the ropivacaine group (p = 0,044). However, this did not lead to an increased ability to get up from bed (p = 0,57) or to walk around (p = 0,17). A high number of patients did not meet the requirements for early ambulation. Almost half of the patients of both groups were unable to leave their beds in the morning of the first postoperative day. On the second postoperative day about 25 - 30 % of the patients could not walk even when support was applied. Furthermore, median reduction (10th/90th percentile) of muscular strength was reduced to 50 % (37 %/76 %) in the ropivacaine group and to 48 % (31 %/61 %) in the bupivacaine group compared with preoperative values.

DISCUSSION: While quality of analgesia was similar, mobility of the legs at rest is better preserved with ropivacaine 0.2 % than with bupivacaine 0.25 %. However, despite the fact that high dose sufentanil was added to both local anaesthetics, there was marked motoric impairment in both groups probably due to the lumbar site of the epidural catheter. This was associated with an unacceptable high incidence of patients unsuitable for early postoperative mobilisation.