A comparison of epidural analgesia with 0.125% ropivacaine with fentanyl versus 0.125% bupivacaine with fentanyl during labor

We previously found that the extent of an epidural motor block produced by 0.125% ropivacaine was clinically indistinguishable from 0.125% bupivacaine In laboring patients. By adding fentanyl to the 0.125% ropivacaine and bup ivacaine solutions in an attempt to reduce hourly local anesthetic requirem ents, we hypothesized that differences in motor block produced by the two d rugs may become apparent. Fifty laboring women were randomized to receive e ither 0.125% ropivacaine with fentanyl 2 mu g/mL or an equivalent concentra tion of bupivacaine/fentanyl using patient-controlled epidural analgesia (P CEA) with settings of: 6-mL/hr basal rate, 5-mL bolus, 10-min lockout, 30-m L/h dose limit. Analgesia, local anesthetic use, motor block, patient satis faction, and side effects were assessed until the time of delivery. No diff erences in verbal pain scores, local anesthetic use, patient satisfaction, or side effects between groups were observed; however, patients administere d ropivacaine/fentanyl developed significantly less motor block than patien ts administered bupivacaine/fentanyl. Ropivacaine 0.125% with fentanyl 2 mu g/mL produces similar labor analgesia with significantly less motor block than an equivalent concentration of bupivacaine/fentanly. Whether this stat istical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the PCEA technique remains to be determined. Implications: By using a patient-controlled epidural analgesia technique, ropivacaine 0.125% with fentanyl 2 mu g/mL produces similar anal gesia with significantly less motor block than a similar concentration of b upivacaine with fentanyl during labor. Whether this statistical reduction i n motor block improves clinical outcome or is applicable to anesthesia prac tices which do not use the patient-controlled epidural analgesia technique remains to be determined.