Phenylephrine in Spinal Anesthesia in Preeclamptic Patients

Ephedrine concentration: 8 mg/mL. The infusion will be initiated immediately after completion of the spinal injection at a rate of 1 mL/min and continued for a minimum of 2 min after which the infusion will be stopped, continued or increased based on the SBP each minute. After each SBP measurement the infusion will be stopped if SBP \> 80% baseline, and the infusion will be continued or restarted if the SBP is approximately equal to 80% baseline. The infusion will be increased by 1 mL/min if the SBP \< 80% baseline. Each time there is hypotension the patient will receive a 1 mL IV bolus of the study solution and the infusion will be increased by 1 mL/min until delivery.

Phenylephrine concentration: 100 mcg/mL. The infusion will be initiated immediately after completion of the spinal injection at a rate of 1 mL/min and continued for a minimum of 2 min after which the infusion will be stopped, continued or increased based on the SBP each minute. After each SBP measurement the infusion will be stopped if SBP \> 80% baseline, and the infusion will be continued or restarted if the SBP is approximately equal to 80% baseline. The infusion will be increased by 1 mL/min if the SBP \< 80% baseline. Each time there is hypotension the patient will receive a 1 mL IV bolus of the study solution and the infusion will be increased by 1 mL/min until delivery.