Norepinephrine and Phenylephrine for Spinal Anesthesia-induced Hypotension.

Not Applicable

Not yet recruiting

• Conditions: Outcome
• Interventions: Drug: Norepinephrine; Drug: Phenylephrine

• Registration Number: NCT06508359
• Lead Sponsor: General Hospital of Ningxia Medical University

Brief Summary

This study aims to explore the effects of different application modes (prophylactic and rescue strategy) of norepinephrine and norepinephrine on neonate umbilical artery pH undergoing cesarean section.

Detailed Description

Spinal anesthesia-induced hypotension is a frequent complication during spinal anesthesia for cesarean section. The incidence of spinal anesthesia-induced hypotension is as high as 62.1-89.7% if prophylactic measures are not taken. The 2016 ASA guidelines for obstetric anesthesia suggest avoiding hypotension following spinal anesthesia in women and emphasize the use of vasopressors, specifically alpha-receptor agonists, as the preferred strategy to prevent and manage spinal anesthesia-induced hypotension. The prophylactic vasopressor strategy is more effective in enhancing hemodynamic stability and reducing adverse events such as nausea and vomiting during cesarean section, compared to rescue strategy. However, it does not demonstrate significant advantages in neonatal outcomes such as umbilical artery pH and Apgar score. The impact of various vasopressor application patterns on neonatal outcomes after cesarean section lacks further supporting evidence. Therefore, this study aims to explore the effects of different application modes (prophylactic and rescue strategy) of norepinephrine and norepinephrine on neonate umbilical artery pH undergoing cesarean section through a multicenter, single-blind, 2\*2 crossover and cluster randomized trial.

Study Timeline

• Status Verified: 2024-07
• Study First Submitted: 2024-07-14
• Study First Submitted QC: 2024-07-14
• Last Update Submitted: 2024-07-14
• Study First Posted: 2024-07-18
• Last Update Posted: 2024-07-18
• Study Start: 2025-03-01
• Primary Completion: 2027-02-28
• Study Completion: 2027-02-28

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: Female
• Target Recruitment: 2000

Inclusion Criteria

• 18-45 years
• Primipara or multipara
• Singleton pregnancy ≥37 weeks
• American Society of Anesthesiologists physical status classification II
• Scheduled for cesarean section under spinal anesthesia

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Exclusion Criteria

• Body height < 150 cm
• Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2
• Eclampsia or chronic hypertension or baseline blood pressure ≥140 mmHg
• Hemoglobin < 7g/dl
• Fetal distress, or known fetal developmental anomaly

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Prophylactic norepinephrine group	Norepinephrine	A maintenance dose of norepinephrine (0.05 ug/kg/min) infusion simultaneous with spinal anesthesia. The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery.
Rescue norepinephrine group	Norepinephrine	The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery. Spinal anesthesia-induced hypotension is managed by administering a 6 μg intravenous bolus of norepinephrine.
Prophylactic phenylephrine group	Phenylephrine	A maintenance dose of phenylephrine (0.625 ug/kg/min) infusion simultaneous with spinal anesthesia. The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery.
Rescue phenylephrine group	Phenylephrine	The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery. Spinal anesthesia-induced hypotension is managed by administering a 75 μg intravenous bolus of phenylephrine.

Primary Outcome Measures

Name	Time	Method
Base excess (BE)	Immediately after delivery	From umbilical arterial blood gases.
pH	Immediately after delivery	From umbilical arterial blood gases.

Secondary Outcome Measures

Name	Time	Method
Partial pressure of oxygen (PO2)	Immediately after delivery	From umbilical arterial blood gases.
The incidence of hypertension	1-15 minutes after spinal anesthesia	Systolic blood pressure (SBP) \>120% of the baseline.
The incidence of nausea and vomiting	1-15 minutes after spinal anesthesia	Presence of nausea and vomiting in patients after spinal anesthesia
The incidence of post-spinal anesthesia hypotension	1-15 minutes after spinal anesthesia	Systolic blood pressure (SBP) \< 80% of the baseline
The incidence of bradycardia	1-15 minutes after spinal anesthesia	Heart rate \< 60 beats/min
The incidence of severe post-spinal anesthesia hypotension	1-15 minutes after spinal anesthesia	Systolic blood pressure (SBP) \< 60% of the baseline
APGAR score	5 min after delivery	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration