Ambulatory patient contolled epidural analgesia (PCEA) for labor using ropivacaine: a comparative study of three different concentrations: a randomized double-blind controlled trial

ABSTRACT

Objective: This study determined the efficacy and safety of three different concentrations of ropivacaine hydrochloride via patient controlled epidural analgesia (PCEA) for ambulatory pain. Specifically, labor analgesic efficacy, manifestation of motor block, frequency of demand dosing, adverse side effects, incidence of spontaneous, instruments, and surgical deliveries, parturient and obstetrician satisfaction of the pain regimen, and neonatal outcome were assessed. Design: A randomized, double-blind controlled trial. Setting: University of Santo Tomas Hospital, a tertiary teaching hospital. Populations Fifty-eight parturients of mixed parity, 18-40 years of age. ASA Physical Status I and II, for vaginal delivery were randomly divided into 3 parallel treatment groups. Methods: Group I (21 patients) received PCEA Ropivacaine 0.1 percent. Group II (18 patients) PCEA Ropivacaine 0.05 percent. and Group III (19 patients) PCEA Ropivacaine 0.025 percent. After placement of lumbar epidural catheter, PVEA was started continuous infusion at 8ml/hour, demand bolus of 4 ml, with lockout period of 15 minutes, and an hourly limit of 12 ml were set. After labor relief was achieved (VAS score 0-3), with a block height of at least T10; ambulation under close supervision was allowed if patient has normal motor assessment using straight leg raising test and Bromage scale, intact joint proprioception and vibration sense, and negative orthostatic hypotension. Results: Uterine contraction pain score using the Visual Analogue Scale showed significant difference between the VAS scores before and after the study drug was started (p=0.01). the degree of pain relief was comparable between the three groups (p+0.09). But time-to-onset pain relief was faster in Group I with a mean of 15.5 minutes and slowest in Group III with a mean of 24.68 minutes. Group one had the least mean demands for more analgesic of 13.55 and accepted boluses 2.89 compared to Group III (mean demands 33.21; accepted boluses 8.42). seven percent of the population who require supplemental IV analgesics all belonged to Group III. No motor block and adverse materno-fetal side effects were noted in all three groups. Eighty-eight percent of the patients delivered spontaneously, 10 percent required instrumental deliveries, and one underwent cesarean delivery, with good neonatal outcomes. Conclusions: PCEA Ropivacaine is effective and safe for ambulatory labor pain. Ropivacaine 0.1 percent and 0.05 percent were comparable in their analgesic efficacy, onset of pain relief, patient analgesic demands, with high patient and obstetrician satisfaction. (Author)