Epidural anesthesia with bupivacaine for Cesarean section: neonatal blood levels and neurobehavioral responses.

A recent study found no neurobehavioral change in infants whose mothers received bupivacaine epidural anesthesia (112 +/- 7 mg) for labor and vaginal delivery. The present study was undertaken to examine the possibility that the larger doses of bupivicaine necessary for cesarean section might cause neurobehavioral changes in the neonate. Ten infants delivered by cesarean section with bupivacaine epidural anesthesia (168 +/- 7 mg) was assessed by Scanlon's neonatal neurobehavioral examination. They were compared in a prospective randomized study with a control group of ten infants delivered with tetracaine spinal anesthesia. In the experimental group bupivacaine was detectable in umbilical arterial blood (.17 +/- .07 microgram/ml), umbilical venous blood (.21 +/- .09 microgram/ml), and neonatal blood samples at 4 hours of age (.04 +/- .04 microgram/ml). By 24 hours of age bupivacaine was no longer detectable in newborn blood samples. Infants in the experimental group were indistinguishable from control infants in terms of their motor organization, responsiveness to external stimuli, and habituation to repetitive stimuli. Detectable neurobehavioral effects were absent despite the fact that 1.5 times the dose of bupivacaine used for labor and vaginal delivery was employed in this study.