Up-Down Determination of the 90% Effective Dose of Phenylephrine for the Treatment of Spinal Anesthesia-Induced Hypotension in Parturients Undergoing Cesarean Delivery

• DOI: 10.1213/ane.0b013e3181c30b72
• Publication Date: 2009-12-17T13:31:34Z
• Authors: Ronald B. George; Dolores McKeen; Malachy O. Columb; Ashraf S. Habib
• Keywords: Phenylephrine; Cesarean delivery

Hypotension frequently complicates spinal anesthesia for cesarean delivery, and vasopressors are the mainstay treatment. The most effective dose of phenylephrine treatment anesthesia-induced hypotension has not been estimated.Healthy nonlaboring women undergoing a delivery were recruited. All received using hyperbaric bupivacaine 12 mg with fentanyl morphine. Each subject an i.v. crystalloid fluid bolus before at time initiation (preload coload). An up-down sequential allocation method biased-coin design was used to estimate 90% (ED(90)) phenylephrine. assigned based on response preceding subject. If systolic blood pressure (SBP) decreased > 20% baseline (i.e., SBP 20%) or < 90 mm Hg, administered. returned within = Hg 1 min, this considered success, otherwise it failure. initial 100 microg. ED(90) 95% confidence intervals (CIs) calculated maximum likelihood estimation Firth logistic regression.Sixty-nine subjects screened participate, whom 66 consented. Forty-five enrolled experienced blinded Those who developed doses between 80 180 No hypertension. Determined method, 147 microg (95% CI, 98-222 microg). With regression, probability successful 150 is 90.5% 66.0%-99.0%).In study, we estimated that required treat in approximately