[Comparative study of peridural anesthesia with bupivacaine alone and combined with fentanyl during vaginal delivery]. / Estudio comparativo entre la anestesia peridural con bupivacaína sola o asociada a fentanilo durante el parto vaginal.

Two groups of primiparous women with single fetus in cephalic presentation were prospectively randomized at the end of pregnancy to receive epidural analgesia with 0.25% bupivacaine, either single (n = 102) or associated with 0.05 mg of phentanyl (n = 102). Phentanyl significantly reduces the period of development of analgesia and increases the interdose period. The quality of analgesia is significantly better when fentanyl is associated with bupivacaine. The evolution of delivery (dilatation and expulsion) and the perinatal results (cord pH and vitality of the newborn as assessed by the Apgar test) were similar in both groups. We conclude that the association of phentanyl with bupivacaine has advantages for epidural analgesia during delivery, as the quality of analgesia is improved, its duration is prolonged and there are no adverse effects on the evolution of delivery or on the newborn.