A randomized comparison of hemodynamic changes in response to a heart rate-dependent phenylephrine/ephedrine protocol versus ephedrine-only for spinal hypotension during elective cesarean section.

Aim: To compare incidences of abnormal heart rate (HR) between the phenylephrine/ephedrine protocol (P/E protocol) against the ephedrine-only (C) protocol, conventionally used for treating predelivery hypotension following spinal anesthesia for cesarean section.

Methods: Two hundred and sixty-eight parturients with pre-delivery hypotension after spinal anesthesia were equally randomized to (1) Group P/E (n = 134), phenylephrine 100 mcg in 10 mL intravenously if HR ≥ 60 beats/min (bpm), or ephedrine 6 mg intravenously if HR < 60 bpm, and 2) Group C (n = 134). The primary outcome was the incidence of the parturients with abnormal HR after vasopressor administration.