Preload Optimization Guided by Inferior Vena Cava Collapsibility Index

Study Overview
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Brief Summary
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The purpose of this study is to investigate the optimal preload guided by inferior vena cava collapsibility index in parturients with prophylactic norepinephrine infusion undergoing cesarean section.

Detailed Description
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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. Vasopressors has been highly recommended for routine prevention and/or treatment of post-spinal anesthesia hypotension. As a potential substitute drug for phenylephrine, norepinephrine has gradually been used in parturients undergoing cesarean section. There's some evidence that prophylactic infusion of norepinephrine could effectively reduce the incidence of post-spinal anesthesia hypotension in parturients undergoing cesarean section. However, the investigator's study (NCT03997500) had been shown that inferior vena cava collapsibility index (IVC-CI) markedly decreased in prophylactic norepinephrine infusion versus normal saline after spinal anesthesia and fetal delivery, suggesting that more prudent fluid management is required. The ideal dose of preload and coload is still unknown. Thus, the purpose of this study is to investigate the optimal preload guided by IVC-CI in parturients with prophylactic norepinephrine infusion undergoing cesarean section.

Official Title
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Preload Optimization Guided by Inferior Vena Cava Collapsibility Index in Parturients With Prophylactic Norepinephrine Infusion Undergoing Cesarean Section: a Randomized, Dose-finding Trial

Conditions
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Adverse Effect

Intervention / Treatment
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* Drug: Control group
* Drug: 4 ml/kg group.
* Drug: 8 ml/kg group.
* Drug: 12 ml/kg group.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-40 years Primipara or multipara Singleton pregnancy ≥37 weeks American Society of Anesthesiologists physical status classification I to II Scheduled for elective 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 ≥ 160mmHg Hemoglobin < 7g/dl Fetal distress, or known fetal developmental anomaly

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Control group<br>No preload was given before spinal anesthesia | Drug: Control group<br>* No preload was given before spinal anesthesia.<br>* Other names: Crystalloid;|
| Experimental: 4 ml/kg group<br>4 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia | Drug: 4 ml/kg group.<br>* 4 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia.<br>* Other names: Crystalloid;|
| Experimental: 8 ml/kg group<br>8 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia. | Drug: 8 ml/kg group.<br>* 8 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia.<br>* Other names: Crystalloid;|
| Experimental: 12 ml/kg group<br>12 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia. | Drug: 12 ml/kg group.<br>* 12 ml/kg compound sodium chloride (0.85% NaCl, 0.03% KCl, and 0.033% CaCl2) was given before spinal anesthesia.<br>* Other names: Crystalloid;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The minimum (IVC-min), maximum diameter (IVC-max) and collapsibility index (IVC-CI) of the inferior vena cava (IVC) | IVC-CI = [(IVC-max-IVC-min) /IVC-max*100%] | Baseline (before preload) | 
| The minimum (IVC-min), maximum diameter (IVC-max) and collapsibility index (IVC-CI) of the inferior vena cava (IVC) | IVC-CI = [(IVC-max-IVC-min) /IVC-max*100%] | Before spinal anesthesia (after preload) | 
| The minimum (IVC-min), maximum diameter (IVC-max) and collapsibility index (IVC-CI) of the inferior vena cava (IVC) | IVC-CI = [(IVC-max-IVC-min) /IVC-max*100%] | 5 min after spinal anesthesia | 
| The minimum (IVC-min), maximum diameter (IVC-max) and collapsibility index (IVC-CI) of the inferior vena cava (IVC) | IVC-CI = [(IVC-max-IVC-min) /IVC-max*100%] | 5 min after fetal delivery | 
| The minimum (IVC-min), maximum diameter (IVC-max) and collapsibility index (IVC-CI) of the inferior vena cava (IVC) | IVC-CI = [(IVC-max-IVC-min) /IVC-max*100%] | Before leaving the operating room | 

Secondary 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 | 
| 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 < 55 beats/min. | 1-15 minutes after spinal anesthesia | 
| The incidence of hypertension | Systolic blood pressure (SBP) >120% of the baseline | 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 | 1min after delivery | 
| APGAR score | A= Appearance P=Pulse G=Grimace A=Attitude R=Respiration | 5min after delivery | 
| 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. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Preload, Inferior vena cava collapsibility index, Norepinephrine, Cesarean section, Dose-finding