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

Adverse Effect Clinical Trial

Official title:

90% Effective Dose of Phenylephrine Infusions for Preventing Postspinal Anesthesia Hypotension Under Intensive and Standard Treatment in Preeclamptic Patients During Cesarean Section

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT06151470
• Other study ID #: Yi Chen-2024-8
• Status: Not yet recruiting
• Phase: N/A
• Start date: July 1, 2025
• Est. completion date: December 31, 2025

Study information

• Verified date: November 2023
• Source: General Hospital of Ningxia Medical University
• Contact: Yi Chen, M.D.
• Phone: 86-951-674-3252
• Email: czzyxgp[@]163.com
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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

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.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 80
• Est. completion date: December 31, 2025
• Est. primary completion date: December 31, 2025
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 18 Years to 45 Years

Eligibility

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

Related Conditions & MeSH terms

• Adverse Effect

Intervention

Drug:
• Alpha-Agonist
An initial infusion dose of prophylactic phenylephrine (0.625 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.125 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.
• a-adrenergic receptor agonist
An initial infusion dose of prophylactic phenylephrine (0.625 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.125 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
General Hospital of Ningxia Medical University

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	ED50 and ED90	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	1-15 minutes after spinal anesthesia
Secondary	The incidence of post-spinal anesthesia hypotension	Systolic blood pressure (SBP) < 80% of the baseline	1-15 minutes after spinal anesthesia
Secondary	The incidence of severe post-spinal anesthesia hypotension.	Systolic blood pressure (SBP) < 60% of the baseline.	1-15 minutes after spinal anesthesia
Secondary	The incidence of bradycardia.	Heart rate < 60 beats/min.	1-15 minutes after spinal anesthesia
Secondary	The incidence of nausea and vomiting.	Presence of nausea and vomiting in patients after spinal anesthesia	1-15 minutes after spinal anesthesia
Secondary	The incidence of hypertension.	Systolic blood pressure (SBP) >120% of the baseline.	1-15 minutes after spinal anesthesia
Secondary	pH	From umbilical arterial blood gases.	Immediately after delivery
Secondary	Base excess	From umbilical arterial blood gases.	Immediately after delivery
Secondary	Partial pressure of oxygen (PO2)	From umbilical arterial blood gases.	Immediately after delivery
Secondary	APGAR score	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)	1 min after delivery
Secondary	APGAR score	A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration; 0(Worst)-10(Best)	5 min after delivery