Norepinephrine has emerged as a potential alternative for stabilizing blood pressure during spinal anesthesia for cesarean section, purportedly maintaining maternal heart rate and cardiac output more effectively than phenylephrine. However, its application as an intravenous bolus for treating hypotension remains underexplored. Consequently, this current investigation aimed to determine the ED50 and ED95 of norepinephrine for managing maternal hypotension during cesarean section. A prospective trial enrolled 100 patients undergoing elective delivery under spinal anesthesia, with norepinephrine dosage determined using the upper and lower sequential distribution method (UDM).

Inclusion Criteria:

Inclusion criteria included women undergoing elective caesarean section undergoing combined lumbar and rigid anaesthesia, healthy singleton pregnancies at full term (more than 37 weeks gestation), American Society of Anaesthesiologists physical status I or II, body weight between 50-100 kg, height between 150-180 cm, and fasting for more than 8 hours.

Exclusion Criteria:

The exclusion criteria included individuals with hypertension, cardiovascular diseases, preeclampsia, arrhythmias, diabetes mellitus, spinal cord malformations, abnormal fetal conditions, and those who declined to participate in the study.