Phenylephrine is considered the preferred vasopressor in obstetrics due to its high efficacy, ease of titration, and ability to prevent nausea and vomiting without causing fetal acidosis.
PURPOSE OF REVIEW: Historically, ephedrine has been recommended as the best vasopressor in obstetrics because animal studies showed it caused less reduction in uterine blood flow compared with alpha-agonists. Recent clinical evidence, however, suggests that this is not as important as initially thought. This review evaluates current data with a focus on spinal anesthesia for cesarean section. RECENT FINDINGS: Ephedrine and phenylephrine have been most investigated. Advantages of ephedrine include familiarity, long history and low propensity for uteroplacental vasoconstriction. Ephedrine, however, has limited efficacy, is difficult to titrate, causes maternal tachycardia and depresses fetal pH and base excess. Advantages of phenylephrine include high efficacy, ease of titration and the ability to use liberal doses to maintain maternal blood pressure near normal and then prevent nausea and vomiting without causing fetal acidosis. Phenylephrine, however, may decrease maternal heart rate and cardiac output and few data are available on its use in high-risk cases. Combination of a phenylephrine infusion and rapid crystalloid cohydration is the first method described that reliably prevents hypotension. SUMMARY: When current evidence is considered, in the authors' opinion, phenylephrine is the vasopressor that most closely meets the criteria for the best vasopressor in obstetrics.
Kee et al. (Fri,) conducted a review in Spinal anesthesia for cesarean section. Phenylephrine vs. Ephedrine was evaluated. Phenylephrine is considered the preferred vasopressor in obstetrics due to its high efficacy, ease of titration, and ability to prevent nausea and vomiting without causing fetal acidosis.