a comparative study of prophylactic norepinephrine and phenylephrine infusion for controlling spinal anaesthesia induced hypotension in parturients undergoing lower section caesarean section-randomized clinical trial

Spinal anaesthesia is the most commonly preferred type of anaesthesia in elective cesarean section. But hypotension following spinal anaesthesia is a common and dreadful complication. The use of nonpharmacological methods is not found to be effective, hence use of vasopressor is indicated in the management of hypotension. Among vasopressors norepinephrine and phenylephrine are used.

Here, in our study, we will compare the infusion doses of two drugs to prevent spinal anesthesia-induced hypotension. We will also try to find out the vasopressor (phenylephrine or norepinephrine) that brings the most stable hemodynamic response and least adverse reactions.

A total of 104 parturients, aged 18 to 45 years belonging to the American Society of Anaesthesiologists (ASA) I and II, undergoing lower segment caesarean section under spinal anaesthesia will be divided into two groups (Group A and Group B) by block randomization. Group A patients will receive norepinephrine 60ml/hr as intravenous infusion, group B patients will receive phenylephrine 60ml/hr as intravenous infusion, after subarachnoid block at the rate of 1ml/kg/hr. The number of occurrences of hypotension (before delivery and after delivery) will be noted. Hemodynamic parameters will be monitored and recorded. The baseline values will be compared with the values obtained after spinal block in all four groups. The incidence of bradycardia, hypertension, and fetal outcomes such as Apgar score and umbilical vein blood gases will also be recorded.

The findings and observations made during the entire study will be tabulated, graphically depicted whenever possible, statistically analyzed and inference will be drawn.