Randomized double blind comparison of phenylephrine and norepinephrine boluses for treatment of post-spinal hypotension during elective caesarean section

This study is a randomized, double blind, parallel group trial comparing phenylephrine and norepinephrine for the treatment of post-spinal hypotension in patients undergoing elective caesarean section. Post-spinal hypotension, defined as fall of SBP 20% or more from the baseline or an absolute SBP less than100 mm Hg, whichever is higher; will be treated with inj. phenylephrine 100 microg iv or inj. norepinephrine 5 microg iv. Umbilical arterial and venous blood samples of the fetus will be obtained from a segment of umbilical cord double clamped before the baby’s first breath for blood gas analysis. The primary outcome measure will be incidence of maternal bradycardia (HR  below 60 per minute). The secondary outcome measures will be change in maternal SBP, number of episodes of hypotension, total vasopressor doses given, Apgar scores at 1 and 5 minutes, incidence of fetal acidosis (defined as umbilical artery pH  less than 7.20), incidence of tachycardia/bradycardia/ arrhythmias/hypertension, incidence of nausea, vomiting, dizziness or any other complications.