Ropivacaine 1 mg/ml, plus fentanyl 2 μg/ml for epidural analgesia during labour.: Is mode of administration important?

Background: Patient-controlled epidural analgesia (PCEA) with a moderate to high concentration of bupivacaine in obstetrics has been shown to give comparable analgesia and even higher level of satisfaction compared to continuous epidural infusion. We hypothesised that the use of a very low concentration technique (ropivacaine/fentanyl) might result in excessive dosing in the PCEA group, more motor blockade and a negative impact on spontaneous delivery rate. Methods: We conducted a randomised, double-blind study of 60 nulliparous women at term comparing low concentration ropivacaine/fentanyl administered in either patient-controlled or fixed continuous infusion mode. Parturients with known predictors of painful deliveries, i.e. breech presentation, primary induction of labour, were not included. Deliveries within 90 min from the start of epidural analgesia were omitted from the evaluation. Results: We found that both groups required a mean of 12 ml/h low concentration mixture (loading and midwife rescue boluses included). There was no difference between groups with respect to spontaneous delivery rate (71%). This low concentration technique resulted in haemodynamic stability without crystalloid preloading, infusion or vasopressor use. Motor blockade of clinical importance was not detected in any patient. Conclusion: We conclude that epidural use of ropivacaine 1 mg/ml+fentanyl 2 mug/ml provides effective analgesia with equal volume requirements irrespective of administration mode, with a high spontaneous delivery rate. Choice of PCEA or CEI (continuous epidural infusion) should be directed by other considerations, most importantly compliance of midwife and possible reduction in workload for anaesthesiology staff.