Effect of Ephedrine and Norepinephrine on Fetal Acidosis During Cesarean Section Under Spinal Anesthesia: A Prospective, Randomized Controlled Trial
Phase: PHASE4
Conditions: Cesarean Delivery Affecting Newborn, Acidosis, Maternal Hypotension, Spinal Aneshtesia
Sponsor: mehmet özkılıç

Study Protocol and Statistical Analysis Plan
Document Date: June 12, 2025
Title: Comparative Effects of Ephedrine and Norepinephrine on Fetal Acidosis in Cesarean
Deliveries Under Spinal Anesthesia: A Prospective, Randomized Controlled Trial
Background:
Maternal hypotension is a frequent complication of spinal anesthesia in cesarean sections.
Ephedrine and norepinephrine are two commonly used vasopressors. Recent studies suggest
norepinephrine may be associated with a lower incidence of fetal acidosis compared to ephedrine
due to its distinct pharmacodynamic profile.
Objective:
To compare the effects of intravenous ephedrine versus norepinephrine on fetal acidosis prevention
in patients undergoing cesarean delivery under spinal anesthesia.
Methods:
Design: Prospective, double-blind, randomized controlled trial.
Setting: Gazi YaIargil Training and Research Hospital, DiyarbakIr, Türkiye.
Population: 100 healthy parturients (ASA I-II) scheduled for elective cesarean delivery under spinal
anesthesia.
Interventions: Patients will be randomly assigned to receive ephedrine (5-10 mg) or norepinephrine
(5-10 µg) intravenously in response to hypotension.
Primary Outcome: Umbilical artery pH < 7.20.
Secondary Outcomes: Incidence of maternal hypotension, maternal and fetal tachycardia, Apgar
scores, additional vasopressor requirements.
Ethics:
The study has received ethical approval from the Harran University Clinical Research Ethics
Committee (Decision No: HRÜ/25.08.38).
Informed consent will be obtained from all participants prior to inclusion.
Statistical Analysis Plan:
Statistical analyses will be performed using SPSS v25.
Categorical variables will be compared using Chi-square or Fisher's exact test.

Continuous variables will be tested for normality (Shapiro-Wilk test).
Normally distributed variables will be compared using Student's t-test; non-normally distributed
variables using the Mann–Whitney U test.
Logistic regression will be used to identify predictors of fetal acidosis.
A p-value < 0.05 will be considered statistically significant.
Sample Size Justification:
Based on previous literature, an expected incidence of fetal acidosis of 20% with ephedrine and 7%
with norepinephrine was used to calculate a minimum of 47 subjects per group with 80% power and
α = 0.05. To account for dropouts, 50 patients per group will be recruited.