Phenylephrine Prophylaxis for Postspinal Anesthesia Hypotension in Parturients With Preeclampsia

Phenylephrine Prophylaxis for Postspinal Anesthesia Hypotension in Parturients With Preeclampsia Undergoing Cesarean Section: a Randomized, Placebo-controlled Dose-finding Trial

The purpose of this study is to investigate the suitable infusion dose of phenylephrine for prophylaxis against postspinal anesthesia hypotension in parturients with preeclampsia undergoing cesarean section.

Study Overview

• Status: Not yet recruiting
• Conditions: Adverse Effect
• Intervention / Treatment: Drug: Normal saline; Drug: Phenylephrine

Detailed Description

Preeclampsia, which affects 5% to 7% of parturients, is a significant cause of maternal and neonatal morbidity and mortality. Because of constricted myometrial spiral arteries with exaggerated vasomotor responsiveness, though blood pressure in parturients with preeclampsia are apparently higher than healthy parturients, placental hypoperfusion is more common. Spinal anesthesia is still the preferred mode of anesthesia in parturients with preeclampsia for cesarean section. In preeclampsia parturients, spinal anesthesia improve intervillous blood flow (provided that hypotension is avoided) which contribute to increase placental perfusion. Even so, 17-26% parturients with preeclampsia experienced postspinal anesthesia hypotension due to the extensive sympathetic block that occurred with spinal anesthesia. Practical guidelines for obstetric anesthesia from the American Society of Anesthesiologists and an international consensus statement on the management of hypotension with vasopressors indicate either IV ephedrine or phenylephrine may be used to correct hypotension. But the suitable infusion dose of phenylephrine in parturients with preeclampsia is still unknown. The purpose of this study is to investigate the suitable infusion dose of phenylephrine for prophylaxis against post-spinal anesthesia hypotension in parturients with preeclampsia undergoing cesarean section.

• Study Type: Interventional
• Enrollment (Anticipated): 95
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• 18-45 years
• Primipara or multipara
• Singleton pregnancy ≥32 weeks
• American Society of Anesthesiologists physical status classification II to III
• Scheduled for cesarean section under spinal anesthesia

Exclusion Criteria:

• Baseline blood pressure ≥180 mmHg
• Body height < 150 cm
• Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2
• Eclampsia or chronic hypertension
• Hemoglobin < 7g/dl
• Fetal distress, or known fetal developmental anomaly

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control group; Normal saline infusion simultaneous with subarachnoid block	Drug: Normal saline; Normal saline infusion simultaneous with subarachnoid block; Other Names: NS
Experimental: 0.3125 μg/kg/min group; A maintenance dose of phenylephrine (0.3125 μg/kg/ min) infusion simultaneous with subarachnoid block	Drug: Phenylephrine; Different infusion dose of phenylephrine simultaneous with subarachnoid block; Other Names: Vasopressors
Experimental: 0.625 μg/kg/min group; A maintenance dose of phenylephrine (0.625 μg/kg/ min) infusion simultaneous with subarachnoid block	Drug: Phenylephrine; Different infusion dose of phenylephrine simultaneous with subarachnoid block; Other Names: Vasopressors
Experimental: 0.9375 μg/kg/min group; A maintenance dose of phenylephrine (0.9375 μg/kg/ min) infusion simultaneous with subarachnoid block	Drug: Phenylephrine; Different infusion dose of phenylephrine simultaneous with subarachnoid block; Other Names: Vasopressors

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The incidence of post-spinal anesthesia hypotension	Systolic blood pressure (SBP) < 80% of the baseline	1-15 minutes after spinal anesthesia

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The incidence of hypertension.	Systolic blood pressure (SBP) >120% of the baseline.	1-15 minutes after spinal anesthesia
Overall stability of systolic blood pressure control versus baseline	Evaluated by performance error (PE)	1-15 minutes after spinal anesthesia
Overall stability of heart rate control versus baseline	Evaluated by performance error (PE)	1-15 minutes after spinal anesthesia
The incidence of severe post-spinal anesthesia hypotension	Systolic blood pressure (SBP) < 60% of the baseline	1-15 minutes after spinal anesthesia
The incidence of nausea and vomiting	Presence of nausea and vomiting in patients after spinal anesthesia	1-15 minutes after spinal anesthesia
The incidence of bradycardia	Heart rate < 60 beats/min	1-15 minutes after spinal anesthesia
pH	From umbilical arterial blood gases.	Immediately after delivery
Partial pressure of oxygen	From umbilical arterial blood gases.	Immediately after delivery
Base excess	From umbilical arterial blood gases.	Immediately after delivery
APGAR score	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration	1 min after delivery
APGAR score	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration	5 min after delivery

Collaborators and Investigators

• Sponsor: General Hospital of Ningxia Medical University
• Investigators: Study Chair: Xinli Ni, Dr., Hospital of Ningxia Medical University

Study record dates

Study Major Dates

• Study Start (Anticipated): October 1, 2023
• Primary Completion (Anticipated): September 21, 2025
• Study Completion (Anticipated): September 21, 2025

Study Registration Dates

• First Submitted: September 30, 2020
• First Submitted That Met QC Criteria: September 30, 2020
• First Posted (Actual): October 6, 2020

Study Record Updates

• Last Update Posted (Actual): November 29, 2021
• Last Update Submitted That Met QC Criteria: November 25, 2021
• Last Verified: September 1, 2021

More Information

Terms related to this study

• Keywords: Cesarean section; Preeclampsia; Phenylephrine; Postspinal anesthesia hypotension; Dose-finding
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Pregnancy Complications; Hypertension, Pregnancy-Induced; Hypotension; Pre-Eclampsia; Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Autonomic Agents; Peripheral Nervous System Agents; Protective Agents; Adrenergic alpha-Agonists; Adrenergic Agonists; Cardiotonic Agents; Respiratory System Agents; Sympathomimetics; Vasoconstrictor Agents; Mydriatics; Nasal Decongestants; Adrenergic alpha-1 Receptor Agonists; Phenylephrine; Oxymetazoline
• Other Study ID Numbers: Yi Chen-2020-6

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No