A Comparative Study of Bolus Norepinephrine, Phenylephrine, and Ephedrine for the Treatment of Maternal Hypotension in Parturients with Preeclampsia During Cesarean Delivery Under Spinal Anesthesia

BACKGROUND: This study aimed to compare the efficacy and safety of bolus norepinephrine, phenylephrine, and ephedrine in parturient with preeclampsia who had hypotension during cesarean delivery under spinal anesthesia. MATERIAL/METHODS: One hundred and sixty-six parturient women with preeclampsia who had a baseline systolic blood pressure (SBP) <80% during spinal anesthesia for cesarean section were divided into three treatment groups; bolus norepinephrine 4 μg (group N) (n=56), phenylephrine 50 μg (group P) (n=55), and ephedrine 4 mg (group E) (n=55). Primary outcomes included overall SBP and heart rate (HR) until delivery. Secondary outcomes included the incidence of tachycardia (HR >120 bpm), bradycardia (HR <60 bpm), hypertension (SBP >120% baseline), number of boluses of vasopressor required and episodes of hypotension, maternal side effects, and neonatal outcome. RESULTS: Overall HR in group N was significantly increased compared with group P (80.5±12 vs. 76.6±6.9 bpm; P=0.04), and significantly lower compared with group E (80.5±12 vs. 84.9±7.1 bpm; P=0.02). Parturients in group N had fewer episodes of bradycardia compared with group P (3.6% vs. 21.8%; RR=0.26l; 95% CI, 0.07–0.73; P=0.004) and fewer episodes of tachycardia compared with group E (16.1% vs. 36.4%; RR 0.54; 95% CI, 0.29–0.90; P=0.02). CONCLUSIONS: A bolus dose of norepinephrine showed similar efficacy to phenylephrine but improved maternal and neonatal safety in parturients with preeclampsia with hypotension during cesarean section under spinal anesthesia.