Effects of three different bolus doses of Norepinephrine for preventing Hypotension during Spinal Anaesthesia for caesarean delivery. A Randomized Clinical Trial

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 bolus for management of spinal hypotension by recording the incidence of successful treatment of hypotension which is considered when systolic blood pressure increases by 20 percent  within 2 minutes of the administration of different regimens of norepinephrine bolus. We will also try to find which regimen provides better hemodynamic stability and fetal outcome with least adverse reactions.

A total of 150 parturient  aged 18 to 45 years belonging to American society of Anaesthesiologists ASA I and II undergoing lower segment caesarean section under spinal anaesthesia will be divided into three groups of Group A Group B and Group C by block randomization. Group A patients will receive norepinephrine 5 microgram as intravenous bolus  group B patients will receive norepinephrine 8 microgram as intravenous bolus  group C patients will receive norepinephrine 10 microgram  as intravenous bolus whenever the systolic blood pressure fall below 20 percent from the baseline. The incidence of successful treatment of hypotension in each group will be noted. The number of occurrences of hypotension before delivery and after delivery  will be also be recorded. Hemodynamic parameters will be monitored and recorded. The baseline values will be compared with the values obtained after spinal block in all the three 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.