Spinal anaesthesia is the most common preferred type of anaesthesia in elective caesarean section. But hypotension following spinal anaesthesia is a common and dreadful complication. Use of non pharmacological methods are not found to be effective, hence use of vasopressor is indicated in management of hypotension. Among vasopressors norepinephrine is a drug which manages hypotension as well as maintains the hemodynamic parameters of the parturient.

Here, in our study we would find out the optimal dosage of norepinephrine infusion for management of spinal hypotension by recording the incidence of hypotension after different regimens of norepinephrine infusion. We will also try to find which regimen provides better hemodynamic stability and fetal outcome with least adverse reactions.

A total of 120 parturient, aged 18 to 50 years belonging to American society of Anaesthesiologists (ASA) I and II, undergoing lower segment caesarean section under spinal  anaesthesia will be divided into four groups (Group A, Group B, Group C and Group D) by block randomization. Group A patients will receive norepinephrine 5 μg/kg/h as intravenous infusion,  group B patients will receive norepinephrine 8 μg/kg/h as intravenous infusion, group C patients will receive norepinephrine 10 μg/kg/h as intravenous infusion and group D will receive normal saline as intravenous infusion after sub arachnoid block at the rate of 1ml/kg/hr. The number of occurence 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 the four groups. The incidence of bradycardia, hypertension and foetal outcome 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 analysed and inference will be drawn.