Norepinephrine prophylaxis for postspinal anesthesia hypotension in parturient undergoing cesarean section: a randomized, controlled trial

OBJECTIVE To investigate the efficacy and safety of prophylactic infusion of norepinephrine (NE) versus normal saline in patients undergoing cesarean section. METHODS Patients (n = 97) were randomized to receive a bolus of NE (6 μg) immediately following spinal anesthesia with maintenance NE (0.05 μg/kg/min IV) or normal saline (n = 98). The primary endpoint was the incidence of postspinal anesthesia hypotension [systolic blood pressure (SBP) < 80% of baseline] at 1-20 min following spinal anesthesia. Secondary outcomes were the overall stability of SBP control versus baseline, inferior vena cava collapsibility index (IVC-CI), other adverse events (bradycardia, nausea, vomiting, and hypertension), and neonatal outcomes (blood gas values and Apgar scores). RESULTS The rates of postspinal anesthesia hypotension and severe postspinal anesthesia hypotension (SBP < 60% of the baseline) were significantly lower in the NE group (17.5% vs. 62.2%, p < 0.001; 7.2% vs. 17.4%, p = 0.031). In the NE group, SBP remained more stable and closer to baseline (p < 0.001), and IVC-CI values were lower 5 min after spinal anesthesia and 5 min after fetal delivery (p = 0.045; p < 0.001, respectively). Other adverse effects and neonatal outcomes were not different between the two groups. CONCLUSION Prophylactic NE infusion effectively lowers the incidence of postspinal anesthesia hypotension and does not increase other adverse events in patients or neonates.