Norepinephrine versus phenylephrine for postspinal hypotension in parturients undergoing cesarean section: a systematic review and meta-analysis

INTRODUCTION: Multiple studies have compared varying prophylactic and therapeutic doses of norepinephrine and phenylephrine given as either intermittent bolus or fixed-rate infusion to combat postspinal hypotension in patients un-dergoing cesarean section (CS). We conducted a systematic review to figure out the best alternative to treat postspinal hypotension.EVIDENCE ACQUISITION: PubMed and Cochrane databases were extensively searched for eligible RCTs. A total of 15 studies were found eligible and analyzed for the incidence of maternal bradycardia as the primary outcome and other maternal adverse effects, fetal acidosis and Apgar scores at 1 and 5 min as the secondary outcome. Data was analyzed using Review Manager Version 5.3. software.EVIDENCE SYNTHESIS: There was no significant difference in the efficacy of norepinephrine and phenylephrine for managing postspinal hypotension (OR=1.15 [95% CI: 0.91-1.45], P=0.24, I2=0%,moderate quality) in parturients under-going CS. Odds of incidence of maternal bradycardia decrease significantly by 61% with norepinephrine versus phenyl-ephrine (OR=0.39 [95% CI: 0.31-0.49], P<0.00001, I2=27%, high quality evidence). Significant higher umbilical artery mean pH values were observed with NE versus PE (MD=0.0 [95% CI: 0.00 to 0.01], P=0.03), although not clinical rel-evant. However, no significant difference was found in the incidence of other maternal adverse effects and fetal outcomes. CONCLUSIONS: Comparable efficacy for management of postspinal hypotension, though, norepinephrine was found to cause less incidence of maternal bradycardia as compared to phenylephrine.