Comparison of Two Different Norepinephrine Bolus Doses for Management of Spinal Anesthesia-Induced Maternal...

Background/Objectives: The bolus dose of norepinephrine (NE) for the treatment of spinal anesthesia-induced maternal hypotension remains unclear. The aim of this study was to compare the efficacy and safety of two different bolus doses of NE in the treatment of spinal anesthesia-induced maternal hypotension during cesarean section (CS). Methods: This study has a prospective, randomized and double-blinded design. A total of 150 patients with ASA physical status I and II who underwent CS included the study at a tertiary-care university hospital. Patients were randomly assigned to either the 6 µg NE bolus (Group 6 µg, n = 75) or 8 µg NE bolus (Group 8 µg, n = 75) group. The primary outcome of this study was to determine the success rate of treatment using a 6 or 8 µg NE bolus in cases of maternal hypotension. Secondary outcomes included comparing fetal umbilical blood gas values and APGAR scores in neonates born to mothers who received a NE bolus before delivery, determining the incidence of NE-induced reactive bradycardia and hypertension, and comparing the groups for intraoperative nausea and vomiting. Results: The 8 µg group showed fewer hypotensive episodes (245 vs. 174 episodes, p = 0.012) and required fewer norepinephrine boluses. Additionally, the success rate of hypotension treatment was higher in the 8 µg group (61.2% vs. 78.5%, p < 0.001). There was no difference in APGAR scores between the groups of neonates born to women who received norepinephrine before delivery. However, in the group with 8 µg NE, slightly better results were obtained in blood gas samples, excluding the pH value. Nausea was more frequently observed in the 6 µg group (p = 0.046). Conclusions: We concluded that an 8 µg bolus administration of NE was more effective than a 6 µg bolus administration in treating maternal hypotension induced by spinal anesthesia, without any increase in the rate of side effects.