Low-Dose Remifentanil in Preterm Cesarean Section with General Anesthesia: A Randomized Controlled Trial

The conventional technique of general anesthesia induction during a Cesarean section involves the use of opioids only after cord clamping. We hypothesized that the use of remifentanil before cord clamping might reduce the use of maternal supplemental anesthetic agents and improve the maternal hemodynamics status and neonatal adaptation of the preterm neonate.

A phase III, double-blind, randomized, placebo-controlled, hospital-based trial enrolled parturients undergoing a Cesarean section under general anesthesia before 37 weeks of gestation. Block randomization allocated pregnant women to remifentanil or placebo. The primary outcome was the rate of newborns with Apgar scores < 7 at 5 min. Secondary outcomes were maternal hemodynamic parameters, complications of anesthetic induction, use of adjuvant anesthetic agents, neonatal respiratory distress, umbilical cord pH, and lactate levels.

A total of 52/55 participants were analyzed, comprising 27 women in the remifentanil group and 25 in the placebo group. Nine of 27 (33.3%) neonates had an Apgar score < 7 at 5 min in the remifentanil group versus 11/25 (44.0%) in the placebo group (p = 0.45, odds ratio = 0.66, 95 confidence interval 0.20-2.18). The blood cord gases, cognitive, behavior, sensory, sleeping, and feeding scores at 1 and 2 years of corrected age were not different. For the mothers, hemodynamic parameters, anesthesia duration, and the cumulative treatment dose until cord clamping did not differ between the groups.

The use of a low dose of remifentanil before cord clamping for a Cesarean section appears to be safe both for the mother and the preterm newborn, but it does not improve maternal or neonatal outcomes.

ClinicalTrials.gov: NCT02029898.