Comparison of norepinephrine and phenylephrine boluses for the treatment of hypotension during spinal anaesthesia for caesarean section – A randomised controlled trial

BACKGROUND AND AIMS: Hypotension following spinal anaesthesia for caesarean section is common in spite of adequate fluid loading. Phenylephrine is the recommended drug to treat spinal hypotension during caesarean section. Recently, norepinephrine boluses are being suggested as an alternative to phenylephrine boluses. The aim of our study was to compare the effectiveness of bolus doses of norepinephrine with phenylephrine to treat spinal hypotension during caesarean section. METHODS: Fifty patients undergoing elective caesarean section under spinal anaesthesia were randomly assigned into two groups. Group P patients received phenylephrine 50 μg as an intravenous bolus and group N received 4 μg of norepinephrine as intravenous bolus to treat spinal hypotension. The primary objective of our study was to compare the number of bolus doses of norepinephrine or phenylephrine required to treat spinal hypotension. The secondary objectives were to compare the incidence of bradycardia, hypertension, nausea and vomiting in mother and foetal outcomes. RESULTS: The number of boluses of vasopressors required to treat hypotension was significantly lower in group N (1.40 ± 0.577 vs. 2.28 ± 1.061, P = 0.001). The frequency of bradycardia was high in group P, but this difference was not statistically significant (4%vs. 20%, P = 0.192). Maternal complications such as nausea and vomiting and shivering were comparable between the groups. The foetal parameters were also comparable between the two groups. CONCLUSION: Intermittent boluses of norepinephrine are effective in the management of spinal-induced hypotension during caesarean section. The neonatal outcomes were similar in both the groups. Norepinephrine boluses can be considered as an alternative to phenylephrine boluses.