Ephedrine versus phenylephrine for the management of hypotension during spinal anesthesia for cesarean section: an updated meta-analysis.

Aims: A systematic literature review comparing the efficacy of ephedrine and phenylephrine for the management of spinal anesthesia-induced hypotension during Cesarean sections (C-sections) was published in 2002. A number of well-designed trials with controversial results have been published afterward. Therefore, an updated meta-analysis was necessary.

Methods: The MEDLINE, EMBASE, and the Cochrane Library databases were searched (last search performed on September 26, 2011). Pooled risk ratio (RR) or standard mean difference (SMD) and their 95% confidence intervals (95% CI) were calculated for the incidence of intra-operative hypotension or umbilical blood pH values.

Results: A total number of 15 trials and 742 parturients under elective C-sections were analyzed. When used to prevent hypotension, patients receiving ephedrine and phenylephrine did not differ significantly in the incidence of hypotension (RR = 1.22; 95% CI, 0.83-1.80), umbilical arterial pH values (SMD = -0.38; 95% CI, -1.67 to 0.92) or venous pH values (SMD = -0.18; 95% CI, -0.44 to 0.07). And administration routes did not affect the incidence of hypotension and umbilical blood pH values. When used to treat hypotension, patients given ephedrine and phenylephrine had comparable incidence of intra-operative hypotension (RR = 0.79; 95% CI, 0.40-1.56), while parturients receiving phenylephrine had neonates with higher umbilical arterial pH values (SMD = -1.32; 95% CI, -2.35 to -0.30) and venous pH values (SMD = -0.79; 95% CI, -1.09 to -0.49) than those given ephedrine.

Conclusion: Prophylactic use of ephedrine and phenylephrine were both effective in preventing maternal hypotension during C-section under spinal anesthesia; phenylephrine was superior to ephedrine in treating hypotension, evidenced by higher umbilical blood pH values.