BACKGROUND: Epinephrine-containing epidural test dose is used for obstetric epidural anesthesia to identify the unintentional cannulation of an epidural vessel. This study evaluated the effects of an epinephrine test dose during epidural anesthesia with 0.5% ropivacaine in ceasrean section.

METHODS: Seventy healthy pregnant women, scheduled for elective cesarean section were randomly assigned to one of two groups. A lumbar epidural catheter was placed and aspirated. If aspiration was positive for blood or cerebrospinal fluid, the catheter was replaced. All patients received an 3 ml test dose of either 1.5% lidocaine with epinephrine 5µg/ml (group E) or lidocaine only (group C). After test dose, 50µg fentanyl and 20 ml of 0.5% ropivacaine were given to the all patients. Applying the pin prick method and a modified Bromage scoring system, senseory block level and motot block intensity were checked at 5 min intervals for the first hour following ropivacaine injection. After then, they were checked at 15 min intervals for the rest of the test period. Heart rate (HR) and blood pressure (BP) were measured as well.

RESULTS: No significant difference between the two groups was detected in HR, BP, the profile of sensory block, motor scores and the onset of motor block. However, group C showed significantly shorter span of motor block (102 ± 31 min.) than group E (134 ± 32 min.) (P <0.05). There was no significant difference in neonatal outcome, as assessed by Apgar score at delivery. The most common adverse effect in mothers was hypotension. No serious adverse effects were detected in this study.

CONCLUSIONS: We conclude that only the span of motor block by the epidural ropivacaine is affected by epinephrine-containing epidural test dose.