The Effectiveness of Low Dose Fentanyl Bolus Injection in Cesarean Section after Umbilical Cord Clamping

Abstract

BACKGROUND: For anesthesia in cesarean section N2O and low concentrations of inhalation anesthetics are regarded as the anesthetic agent of choice. But a low level of anesthesia frequently leads to increased maternal hemodynamic responses and awareness. The effects of a 3 microgram/kg fentanyl bolus injection after umbilical cord clamping was evaluated in 20 full‐term parturients, scheduled for elective cesarean section, versus to 20 parturients without fentanyl. METHODS: The forty parturients (ASA physical status 1, 2) scheduled for cesarean section were randomized to either a N2O‐enflurane (E group) or a N2O‐enflurane‐fentanyl (F group). Thiopental sodium (4 mg/kg) and succinylcholine (1.5 mg/kg) were administered intravenously for the induction and endotracheal intubation. Anesthesia was maintained with 50% N2O and 1% enflurane in oxygen until delivery. After delivery, the intravenous injection of 0.5 mg/kg of atracurium was administered, controlled ventilation was applied to maintain PetCO2 at 30 to 35 mmHg with N2O (3 L/min) and O2 (1.5 L/min). Immediately after clamping the umbilical cord, 3 microgram/kg of fentanyl (F group only) was administered. Heart rate, blood pressure, awareness, recovery time, postoperative complication and recall were evaluated. RESULTS: Heart rate values at 10 and 20 min after umbilical cord clamping and 5 min after extubation, and mean arterial pressure at 5, 10 and 20 min after umbilical cord clamping in group F were found to be significantly lower than in group E. CONCLUSIONS: We conclude that N2O‐enflurane‐fentanyl at 3 microgram/kg is clinically satisfactory in anesthesia for cesarean section, having no adverse effects on the mother. [By kind permission, KoreaMed, Korean Association of Medical Journal Editors.]