MANAGEMENT OF SPINAL ANAESTHESIA-INDUCED HYPOTENSION DURING CAESAREAN SECTION; A COMPARISON OF EPHEDRINE AND NOREPINEPHRINE

Abstract

Introduction For the majority of caesarean sections, spinal anaesthesia is the preferred anaesthetic technique due to its better safety profile. Hypotension has been the most common adverse effect of spinal anaesthesia for decades. Spinal anaesthesia-induced hypotension if not managed promptly and appropriately could lead to poor maternal and neonatal outcomes. Common vasopressors used in the management of hypotension during spinal anaesthesia include phenylephrine and ephedrine. Currently, norepinephrine is being studied as an alternative to phenylephrine and ephedrine for the management of spinal anaesthesia-induced hypotension. This study sought to compare the effectiveness of intravenous ephedrine and norepinephrine in the aversion of spinal anaesthesia-induced hypotension.

Methods This was a prospective, randomised, double-blind controlled study. After ethical clearance and informed consent, parturients were randomised into A (Ephedrine group) and B (Norepinephrine group). The Ephedrine group received prophylactic ephedrine 5mg, augmented with rescue boluses of ephedrine 5mg intravenously. The Norepinephrine group received prophylactic norepinephrine 5μg, augmented with rescue boluses of norepinephrine 5μg intravenously. The primary outcome was the incidence of spinal anaesthesia-induced- hypotension in the two groups. Secondary outcomes included, the incidence of maternal reactive hypertension, bradycardia, nausea and vomiting, and first and fifth-minute Apgar scores of the neonate. A systematic sampling method was used to select all participants. The chi-squared test was used to analyse categorical data, which were presented as numbers and percentages. Shapiro's rank test was used to determine whether continuous data were normally distributed. STATA version 17 (College Station, Texas) statistical software was used for all computations. A p-value of less than 0.050 with a 95% confidence interval was used as the threshold for statistical significance in all tests.

Results The study involved 138 participants, 69 in each group. The mean demographics of the participants were age (31.99±5.04) years, parity (2.82±1.49), gestational age (38.56±0.75) weeks, and body mass index (BMI) (26.58±3.52) kg/m². The incidence of spinal anaesthesia-induced hypotension was 62.32% in the ephedrine group and 42.03% in the norepinephrine group (p= 0.017). The incidence of reactive hypertension was 13.04% in the ephedrine and 8.82% in the norepinephrine group (p= 0.429). The incidence of bradycardia was 4.35% in the ephedrine group and 4.35% in the norepinephrine group (p= 0.612). The incidence of nausea and vomiting was 8.70% in the ephedrine and 10.14% in the norepinephrine group (p= 0.710). The Apgar scores of neonates in the first and the fifth minutes were not statistically different between the two groups (p= 0.878 and p= 0.827 for the first and the fifth minutes respectively).

Conclusion Norepinephrine maintained maternal systolic arterial pressure better than ephedrine during spinal anaesthesia for caesarean section. However, the outcomes for nausea and vomiting, reactive hypertension, and bradycardia, as well as neonatal outcomes obtained for parturients who received either norepinephrine or ephedrine were similar.