Comparison of Two Norepinephrine Rescue Bolus Doses for Management of Severe Post-Spinal Hypotension During Elective Caesarean Delivery: A Randomized, Controlled Trial.

Background: Post-spinal hypotension is associated with maternal and neonatal complications; therefore, prompt control maternal blood pressure is necessary. In this study, we aimed to compare the efficacy and safety of two norepinephrine bolus doses in the rescue management of severe maternal hypotension during elective Cesarean delivery. Methods: We included full-term pregnant women scheduled for Cesarean delivery under spinal anesthesia. Patients were randomized to receive either 5-mcg norepinephrine (n=79) or 10-mcg norepinephrine (n=79) for treatment of severe postspinal hypotension (systolic blood pressure ≤60% of baseline reading). The management of the hypotensive episode was considered successful if systolic blood pressure was >80% of the baseline within 2 mins of the bolus. The primary outcome was the incidence of successful management of severe post-spinal hypotension. Secondary outcomes included the incidence of reactive bradycardia, reactive hypertension, umbilical blood gases, and neonatal Apgar score at 5-min post-delivery. Results: We included 73 patients in the 5-mcg group and 76 patients in the 10-mcg group into the final analysis. The incidence of successful management of severe hypotensive episodes was comparable between the two groups (43/73 [59%] and 46/76 [60%] in the 5-and 10-mcg group, respectively, Conclusion: In mothers undergoing Cesarean delivery under spinal anesthesia, 10-mcg norepinephrine bolus was not superior to the 5-mcg bolus in the management of severe hypotension. Furthermore, the incidence of reactive bradycardia and hypertension was comparable in the two doses. Clinical Trial Registration: NCT05290740, URL: https://clinicaltrials.gov/ct2/show/NCT05290740.