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.