Norepinephrine Infusion vs Bolus vs Ephedrine for Blood Pressure Stability During Cesarean Delivery in Women With Preeclampsia

Preeclampsia is associated with hemodynamic changes that may complicate blood pressure management during cesarean delivery under spinal anesthesia. Norepinephrine may be administered either as an infusion or intermittent boluses, while ephedrine is another commonly used vasopressor strategy. This study is designed to directly compare these approaches in women with preeclampsia undergoing scheduled cesarean delivery under spinal anesthesia.

This is a prospective, randomized controlled trial that will be conducted at Benha University Hospital. A total of 84 women with preeclampsia will be enrolled and randomly allocated in a 1:1:1 ratio to three groups. The norepinephrine infusion group will receive a prophylactic norepinephrine infusion starting at 0.05 µg/kg/min with titration to maintain systolic blood pressure at or above 80% of baseline. The norepinephrine bolus group will receive 4 µg intravenous norepinephrine boluses when systolic blood pressure falls below 80% of baseline. The ephedrine group will receive 6 mg intravenous ephedrine boluses under the same hypotension criterion. Rescue measures are specified in the study protocol for refractory hypotension.

All participants will undergo pre-anesthetic assessment and intraoperative monitoring including electrocardiography, non-invasive blood pressure monitoring, and pulse oximetry. Spinal anesthesia will be performed using hyperbaric bupivacaine with fentanyl. Hemodynamic monitoring will continue during the procedure and for 2 hours postoperatively.

The primary outcome is hemodynamic control during the first 20 minutes after spinal anesthesia, assessed by hypotension episodes, the need for additional rescue vasopressors, and maintenance of blood pressure within ±20% of baseline. Secondary outcomes include severe hypotension, hypertensive episodes, time to first hypotensive episode, total vasopressor requirements, bradycardia, tachycardia, nausea or vomiting, fluid balance, umbilical cord blood gas measurements, Apgar scores at 1 and 5 minutes, and NICU admission.

Inclusion criteria

Women older than 18 years of age with preeclampsia. American Society of Anesthesiologists (ASA) physical status II-III. Preeclampsia defined by systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg on two measurements at least 4 hours apart in a previously normotensive woman, accompanied by proteinuria (≥300 mg/24 hours or equivalent) or evidence of end-organ dysfunction, such as thrombocytopenia, renal or hepatic impairment, pulmonary edema, or neurological symptoms.

Singleton pregnancy. Gestational age ≥37 weeks. Scheduled cesarean delivery under spinal anesthesia.

Exclusion criteria

Refusal to participate in the study. Chronic hypertension or chronic hypertension with preeclampsia. Comorbid conditions, including diabetes mellitus or cardiovascular disease. Suspected fetal compromise. Emergency cesarean section.