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

Benha University84 enrolled

Overview

This randomized controlled trial will compare norepinephrine infusion, norepinephrine bolus, and ephedrine bolus for maintaining hemodynamic stability during spinal anesthesia for scheduled cesarean delivery in women with preeclampsia. Eighty-four eligible women will be randomly allocated in a 1:1:1 ratio to one of three treatment groups. The primary outcome is hemodynamic control during the first 20 minutes after spinal anesthesia, including the occurrence of hypotension, need for rescue vasopressors, and maintenance of blood pressure within ±20% of baseline. Secondary outcomes include severe hypotension, time to first hypotensive episode, vasopressor requirements, maternal adverse effects, fluid balance, and neonatal outcomes including Apgar scores, umbilical cord blood gases, and NICU admission.

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.

Interventions

Norepinephrine (0.05 μg/kg/min)DRUG

Participants will receive a prophylactic intravenous norepinephrine infusion at 0.05 µg/kg/min, started immediately after spinal injection and titrated by ±0.02 µg/kg/min every 2 minutes to maintain systolic blood pressure at or above 80% of baseline. If hypotension persists despite two vasopressor doses or infusion adjustments, the infusion rate may be increased by 0.02-0.05 µg/kg/min according to the study rescue protocol.

Norepinephrine 4mcgDRUG

Participants will receive intravenous norepinephrine 4 µg as a bolus when systolic blood pressure falls below 80% of baseline, repeated every 2 minutes as needed. If hypotension persists after two vasopressor doses, the norepinephrine bolus may be escalated to 6 µg according to the study rescue protocol.

Ephedrine Bolus 6 mgDRUG

Participants will receive intravenous ephedrine 6 mg as a bolus when systolic blood pressure falls below 80% of baseline, repeated every 3 minutes as needed. If hypotension persists after two vasopressor doses, the ephedrine bolus may be escalated to 10 mg according to the study rescue protocol.

Eligibility

Sex: FEMALEMin age: 18 Years

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

Incidence of Hypotension During the First 20 Minutes After Spinal Anesthesia

The number and proportion of participants experiencing at least one episode of hypotension during the first 20 minutes after spinal anesthesia. Hypotension is defined in the study protocol as systolic blood pressure below 80% of the participant's baseline value.

Time frame: From spinal anesthesia administration through 20 minutes after spinal anesthesia

Secondary Outcomes

the incidence of severe hypotension

severe hypotension defined as (SBP\<70% baseline)

Time frame: From spinal anesthesia administration and through the surgery

Need for Additional Rescue Vasopressors

The proportion of participants who require additional rescue vasopressor administration during the first 20 minutes after spinal anesthesia because of inadequate blood pressure control.

Time frame: During the First 20 Minutes After Spinal Anesthesia

time to first hypotensive episode

(minutes from spinal injection)

Time frame: after spinal anesthesia and throughout the surgery