COMPARISON OF NOREPINEPHRINE AND PHENYLEPHRINE BOLUSES FOR THE TREATMENT OF HYPOTENSION DURING SPINAL ANESTHESIA FOR CESAREAN SECTION.: Spinal anesthesia induced hypotension

Introduction:  Phenylephrine in small boluses of 50 to 100µgm or infusion is commonly used to treat hypotension following spinal anesthesia in addition to fluids transfusion and compression stockings in lower limbs. Noradrenaline, the preferred drug for the management of hypotension in shock is now being tried to treat hypotension following spinal anesthesia in small increments. The present study was carried out to compare the efficacy of noradrenalin over phenylephrine in treating hypotension following spinal anesthesia.   Materials and Methods:  A hundred patients undergoing cesarean section were randomly divided into two groups. One group received phenylephrine 50µgm intravenous bolus and the other group received noradrenalin 4µgm intravenous bolus to treat hypotension following spinal anesthesia. The doses of phenylephrine and noradrenaline required to treat spinal hypotension, the incidence of bradycardia, hypotension, nausea, and vomiting in the mother and fetal outcome were recorded.  Observation:  The number of boluses of vasopressors required to treat hypotension was significantly lower in the noradrenaline group (Group NE=1.36±0.563, Group PE=2.00±0.699, p-value=0.000). The frequency of bradycardia was higher in the phenylephrine group and was statistically significant (Group NE=2 (4%), Group PE=11 (22%) p-value=0.015). Maternal complications such as nausea vomiting and shivering were comparable between the groups. The fetal parameters were also comparable between the two groups.   Conclusion:  Noradrenaline boluses are equally effective as phenylephrine in treating spinal anesthesia-induced hypotension. The incidence of side effects is comparable between the groups.  Recommendation:  Norepinephrine should be considered as an alternative to phenylephrine in spinal anesthesia-induced hypotension