90% Effective Dose of Phenylephrine Infusions Under Intensive and Standard Treatment in Preeclamptic Patients

Not Applicable

Not yet recruiting

• Conditions: Adverse Effect
• Interventions: Drug: Alpha-Agonist; Drug: α-adrenergic receptor agonist

• Registration Number: NCT06151470
• Lead Sponsor: General Hospital of Ningxia Medical University

Brief Summary

The objective of this study is to investigate the 90% effective dose of phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment in preeclamptic patients during cesarean section

Detailed Description

Post-spinal anesthesia hypotension is a frequent complication during spinal anesthesia for cesarean section. The incidence of post-spinal anesthesia 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 post-spinal anesthesia hypotension. The 2018 International Consensus in the United Kingdom and Northern Ireland recommends maintaining maternal systolic blood pressure above 90% of the baseline value following lumbar anesthesia, while avoiding dropping below 80% of the baseline value. Currently, the threshold for maintaining blood pressure above 80% of the baseline value is widely adopted as a standard; however, limited evidence supports the advantage of sustaining maternal blood pressure above 90% of the baseline value. The objective of this study is to investigate the 90% effective dose of phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive and standard treatment in preeclamptic patients during cesarean section.

Study Timeline

• Status Verified: 2023-11
• Study First Submitted: 2023-11-21
• Study First Submitted QC: 2023-11-28
• Last Update Submitted: 2023-11-28
• Study First Posted: 2023-11-30
• Last Update Posted: 2023-11-30
• Study Start: 2025-07-01
• Primary Completion: 2025-12-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: Female
• Target Recruitment: 80

Inclusion Criteria

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

Exclusion Criteria

• Baseline blood pressure ≥160 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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Standard group	Alpha-Agonist	The maternal systolic blood pressure was consistently maintained above 80% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery.
Intensive group	α-adrenergic receptor agonist	The maternal systolic blood pressure was consistently maintained above 90% of the preoperative baseline value from the initiation of spinal anesthesia until fetal delivery.

Primary Outcome Measures

Name	Time	Method
ED50 and ED90	1-15 minutes after spinal anesthesia	The dose of prophylactic phenylephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients

Secondary Outcome Measures

Name	Time	Method
The incidence of severe post-spinal anesthesia hypotension.	1-15 minutes after spinal anesthesia	Systolic blood pressure (SBP) \< 60% of the baseline.
Partial pressure of oxygen (PO2)	Immediately after delivery	From umbilical arterial blood gases.
The incidence of post-spinal anesthesia hypotension	1-15 minutes after spinal anesthesia	Systolic blood pressure (SBP) \< 80% of the baseline
pH	Immediately after delivery	From umbilical arterial blood gases.
Base excess	Immediately after delivery	From umbilical arterial blood gases.
The incidence of bradycardia.	1-15 minutes after spinal anesthesia	Heart rate \< 60 beats/min.
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
APGAR score	5 min after delivery	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)