ED90 of Norepinephrine and Phenylephrine Infusions Under Intensive Treatment

General Hospital of Ningxia Medical University60 enrolled

Overview

The objective of this study is to investigate the ED90 of norepinephrine and phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive treatment during cesarean section

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 ED90 of norepinephrine and phenylephrine infusions for preventing postspinal anesthesia hypotension under intensive treatment during cesarean section

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Adverse Effect

Interventions

NorepinephrineDRUG

An initial infusion dose of prophylactic norepinephrine (0.05 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.01 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.

PhenylephrineDRUG

An initial infusion dose of prophylactic phenylephrine (0.5 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.1 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.

Eligibility

Sex: FEMALEMin age: 18 YearsMax age: 45 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 18-45 years * Primipara or multipara * Singleton pregnancy ≥37 weeks * American Society of Anesthesiologists physical status classification I to II * Scheduled for cesarean section under spinal anesthesia 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 ≥180 mmHg * Hemoglobin \< 7g/dl * Fetal distress, or known fetal developmental anomaly

Locations (1)

General Hospital of Ningxia Medical University

Yinchuan, Ningxia, China

Outcomes

Primary Outcomes

ED50 and ED90

The doses of prophylactic norepinephrine and phenylephrine that would be effective in preventing postspinal anesthesia hypotension in 50% (effective dose, ED 50) and 90% (ED90) of patients

Time frame: 1-15 minutes after spinal anesthesia

Secondary Outcomes

The incidence of post-spinal anesthesia hypotension

Systolic blood pressure (SBP) \< 80% of the baseline

Time frame: 1-15 minutes after spinal anesthesia

Data from ClinicalTrials.gov

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