Comparison of a Modified Regimen of Prophylactic Phenylephrine Boluses Versus Variable Rate Infusion During Elective Cesarean Delivery Under Spinal Anesthesia: A Noninferiority Randomized Double-Blind Study
Medha Mohta, Sorabh Anchal, Geetanjali T. Chilkoti, Archit AggarwalBACKGROUND:
Prophylactic phenylephrine boluses have been found to be as effective as variable rate infusions during elective cesarean delivery but require a higher number of physician interventions to maintain blood pressure near baseline values. Therefore, there is a need to find a feasible regimen of bolus administration that is equally efficacious to the infusion regimen while at the same time requires a comparable number of physician interventions and is thus non-inferior to the infusion regimen.
METHODS:
Healthy pregnant women with term, uncomplicated, singleton pregnancies undergoing elective cesarean delivery under spinal anesthesia were randomly divided into two groups. The Bolus group received a phenylephrine bolus 100 μg immediately after spinal anesthesia and then at every systolic blood pressure value <90% of the baseline. The infusion group received a prophylactic variable-rate infusion of phenylephrine beginning at 50 μg/min and titrated to maintain systolic blood pressure at 90-99% of baseline. The primary outcome was the number of physician interventions needed to maintain the target systolic blood pressure; the secondary outcomes included phenylephrine requirements, incidence of hypotension/hypertension/bradycardia, umbilical arterial and venous blood gas analysis, Apgar scores, and maternal complications. The primary outcome was analyzed in terms of non-inferiority using a non-inferiority margin of two interventions.
RESULTS:
Eighty patients were included in the study. The median (interquartile range [IQR]) number of physician interventions was 6 (5–8) in the infusion group and 3 (2–4) in the bolus group (
CONCLUSIONS:
The modified regimen of prophylactic boluses is non-inferior to variable rate prophylactic phenylephrine infusion in terms of physician interventions needed to maintain systolic blood pressure within the target range and maternal and neonatal outcomes.