Intravenous Bolus of Phenylephrine vs. Norepinephrine in Preventing Hypotension After Spinal Anesthesia

The purpose of the study is to determine if an intravenous bolus of phenylephrine is more effective compared to an intravenous bolus of norepinephrine associated with crystalloid loading for maintaining blood pressure during a spinal anesthetic for a cesarean delivery. Prevention of low blood pressure has been shown to decrease nausea and vomiting during and after cesarean delivery under spinal anesthesia. For elective cesarean delivery, all participants will receive spinal anesthesia with a local anesthetic and sufentanil. This study plans to enroll 120 pregnant women. Patients will be randomly assigned according to a computer generated system to be in one of two groups.