V/Q Matching Variations With PEEP in ARDS According to Compliance-based Phenotypes (France)
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- What is being studied
- The protocol lists: PEEP increase, PEEP decrease.
- Who it may be relevant to
- Registry conditions: ARDS. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- France
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Effect of PEEP on Ventilartion/Perfusion Ratios According to Different Phenotypes in Patients With ARDS (France)
Overview
This study aim to compare the effect of Positive End Expiratory Pressure (PEEP) on ventilation/perfusion mismatch in two phenotypes of patients with moderate-to-severe Acute Respiratory Distress Syndrome (ARDS), characterized by their respiratory system elastance (Ers). Ventilation/perfusion mismatch will be assessed by Electrical Impedance Tomography (EIT).
Detailed description
Acute Respiratory Distress Syndrome (ARDS) is characterized by hypoxemia caused by inflammatory lung injury. Recent studies showed an important variability in ARDS phenotypes . The recent COVID-19 crisis highlighted the presence of ARDS patients with severe hypoxemia and normal respiratory system compliance, and retrospective series confirmed the existence of this atypical ARDS pattern also in non-COVID etiologies.
The dissociation between mechanics and hypoxemia may be related to a specific diversity in the pattern of ventilation-perfusion matching (V/Q matching) among patients with normal compliance and ARDS. In patients with low compliance, V/Q mismatch may be characterized by right-to-left shunt, secondary to collapse of the gravity-dependent regions; while, in patients with normal compliance, V/Q mismatch may show a redistribution of blood flow to hypo-ventilated lung areas by larger dead space and impaired hypoxic vasoconstriction.
These differences may also influence the response to PEEP in terms of gas exchange and lung protection . It may also explain the failure for high PEEP levels to improve significantly mortality in the global ARDS population (i.e., with patients' selection only based on hypoxemia).
Electrical Impedance Tomography (EIT) is a device allowing to assess ventilation and perfusion distribution. Thus, EIT can be used to evaluate global and regional V/Q matching, and could be used to understand mechanisms of hypoxemia, especially in patients with normal mechanics and ARDS.
The aim of this study is to assess V/Q matching according to these different ARDS phenotypes, and to evaluate the effects of PEEP in each one.
Interventions
- Procedure PEEP increase
Positive End Expiratory Pressure (PEEP) will be increased from 5 to 15 cmH2O. - Procedure PEEP decrease
Positive End Expiratory Pressure (PEEP) will be decreased from 15 to 5 cmH2O.
Primary outcome measures
- Difference in ventilation/perfusion mismatch between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
Secondary outcome measures (10)
- Difference in respiratory mechanics between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Difference in oxygenation between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Difference in carbon clearance between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Difference in dead space measured by capnometric volumetry between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Difference in dead space measured by calorimetry between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Difference in venous oxygen saturation between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
- Correlation between V/Q mismatch markers and recruitability [Time frame: immediately after each intervention]
- Correlations between V/Q mismatch assessed by EIT and dead space markers [Time frame: immediately after each intervention]
- Correlations between V.Q mismacth and overdisension and lung collapsus [Time frame: immediately after each intervention]
- Difference in stress index between PEEP 5 and 15 cmH2O according to the two studied phenotypes [Time frame: immediately after each intervention]
Eligibility criteria
Inclusion criteria
- intubated patients with moderate and severe ARDS (Berlin definition, PaO2/FiO2 ≤200 mmHg at PEEP 5 cmH2O)
- undergoing deep sedation
- on controlled mechanical ventilation
- between 24 hours and 5 days after intubation.
Exclusion criteria
- age <18 years old; pregnancy
- patient undergoing legal protection
- contra-indications to EIT (e. g. severe chest trauma or wounds)
- pneumothorax; patient undergoing ECMO
- patient with BMI ≥35 kg/m2
- hemodynamic instability with MAP <60 mmHg despite vasopressors.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Treatment
Study locations
France · 1 center
- Angers Hospital — Angers
Identifiers
NCT: NCT05578742 · 2022-A00649-34