Gas Exchange Derangement Physiopathology in Critically Ill Patients With COVID-19

Study Overview
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Brief Summary
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The study was designed to understand the pathophysiology of gas exchange derangement in critically ill patients with COVID-19. Specifically we will evaluate the effect of 3 different levels of positive end-expiratory pressure (PEEP) and two different levels of inspiratory oxygen fraction (FiO2) on gas exchange by analyzing shunt and dead space. Furthermore, complete respiratory mechanics and distribution of ventilation and perfusion by electrical impedance tomography will be assessed at each level of PEEP.

Official Title
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Gas Exchange Derangement Physiopathology and Response to Different Levels of Positive End-expiratory Pressure in Critically Ill Patients With COVID-19

Conditions
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Respiratory Failure

Intervention / Treatment
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* Procedure: PEEP trial - Electrical Impedance Tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients admitted in intensive care unit for COVID-19 related Acute Respiratory Distress Syndrome (ARDS) requiring invasive mechanical ventilation Exclusion Criteria: Pregnancy Hemodynamic instability (80-90 mmHg increase or 30-40 mmHg decrease systolic arterial pressure compared to baseline value or need of vasopressors to maintain systolic blood pressure higher than 85 mmHg or electrocardiogram evidence of ischemia/arrhythmias) Presence of pneumothorax and/or pneumomediastinum Contraindications to Electrical Impedance Tomography (pacemaker, implantable cardioverter defibrillator, thoracic drainages)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Shunt-group<br>Test of three different levels of positive end-expiratory pressure (PEEP) | Procedure: PEEP trial - Electrical Impedance Tomography<br>* Three different levels of PEEP and two different levels of FiO2 will be tested without changing anything else in the baseline patient ventilation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Shunt at three different levels of positive end expiratory pressure (PEEP) | Shunt measured by arterial and mixed venous blood samples at each level of PEEP | 30 minutes after change of positive end expiratory pressure (PEEP) level | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dead space at three different levels of positive end expiratory pressure (PEEP) | Dead space measured by capnography at each level of PEEP | 30 minutes after change of positive end expiratory pressure (PEEP) level | 
| Shunt and dead space at two different levels of inspiratory oxygen fraction for each level of positive end expiratory pressure (PEEP) | Shunt measured by arterial and mixed venous blood samples and dead space measured by capnography at each level of PEEP | 30 minutes after change of positive end expiratory pressure (PEEP) level | 
| Ventilation/perfusion at three different levels of positive end expiratory pressure (PEEP) assessed by electrical impedance tomography (EIT) | Ventilation/perfusion assessed by Electrical Impedance Tomography at each level of PEEP | 30 minutes after change of positive end expiratory pressure (PEEP) level | 
| Respiratory mechanics at three different levels of positive end expiratory pressure (PEEP) | Respiratory mechanics (including esophageal pressure measurement) assessed at each level of PEEP by performing end-inspiratory and end-expiratory pauses | 30 minutes after change of positive end expiratory pressure (PEEP) level |