Ropivacaine 1 mg/ml, plus fentanyl 2 mu g/ml for epidural analgesia duringlabour. 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 com parable analgesia and even higher level of satisfaction compared to continu ous epidural infusion. We hypothesised that the use of a very low concentra tion technique (ropivacaine/fentanyl) might result in excessive dosing in t he PCEA group, more motor blockade and a negative impact on spontaneous del ivery rate. Methods: We conducted a randomised, double-blind study of 60 nulliparous wo men at term comparing low concentration ropivacaine/fentanyl administered i n either patient-controlled or fixed continuous infusion mode. Parturients with known predictors of painful deliveries, i.e. breech presentation, prim ary induction of labour, were not included. Deliveries within 90 min from t he start of epidural analgesia were omitted from the evaluation. Results: We found that both groups required a mean of 12 ml/h low concentra tion mixture (loading and midwife rescue boluses included). There was no di fference between groups with respect to spontaneous delivery rate (71%). Th is low concentration technique resulted in haemodynamic stability without c rystalloid preloading, infusion or vasopressor use. Motor blockade of clini cal 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 irrespe ctive 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 reducti on in workload for anaesthesiology staff.