Background: The effects of two continuous epidural perfusions of bupivacaine at different small concentrations on maternal analgesia, motor paralysis, the progress of delivery and the newborn were compared.
Patients and methods: Forty primigravida patients were divided into two homogeneous groups, A and B, with 20 patients in each. Group A patients were administered a perfusion of bupivacaine at 0.625% and those of group B received a perfusion of bupivacaine at 0.125%. Both perfusions were administered at 10 mg/hour. The following variables were collected: analgesia (visual analogic scale), time of perfusion, local anesthetic doses, re-injections, tenesmus, APGAR at the first minute, APGAR at 5 minutes, use of forceps and motor paralysis.
Results: The perfusion of bupivacaine 0.125% (group B) was more effective in the control of pain since no re-injections were required in this group. The time of perfusion and delivery was significantly less (p < 0.05) in group B (2.95 +/- 0.74 hours) than in group A (3.42 +/- 0.62 hours). There were no significant differences in the total dose (group A: 55.9 +/- 14.09 mg and group B 57.47 +/- 9.06 mg), tenesmus and APGAR: Instrumentation during delivery carried out in both groups (55% in group A and 30% in group B) was at the limits of significance (p = 0.057). Motor paralysis of the lower limbs did not surpass the value of 1 of the modified Bromage scale in either group.
Conclusions: Both techniques (continuous perfusion of bupivacaine at 0.0625% versus bupivacaine at 0.125%) are effective in the control of pain during the second stage of labour with the perfusion of the latter dose (12.5 mg/hour) being more advantageous by diminishing the length of delivery and achieving continuous analgesia.