How PEEP changes ventilation–perfusion matching in two types of ARDS lungs

Effect of PEEP on Ventilartion/Perfusion Ratios According to Different Phenotypes in Patients With ARDS (France)

NA · University Hospital, Angers · NCT05578742

This trial will test whether increasing or decreasing PEEP changes ventilation–perfusion matching in adults with moderate-to-severe ARDS who are sedated and on a ventilator.

Quick facts

PhaseNA
Study typeInterventional
Enrollment50 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity Hospital, Angers (other gov)
Locations1 site (Angers, Maine et Loire)
Trial IDNCT05578742 on ClinicalTrials.gov

What this trial studies

Researchers will classify intubated ARDS patients by respiratory system elastance into two compliance-based phenotypes and then apply stepwise PEEP increases and decreases while measuring regional ventilation and perfusion with Electrical Impedance Tomography (EIT). The protocol enrolls adults 24 hours to 5 days after intubation who are deeply sedated and on controlled mechanical ventilation, excluding those with contraindications to EIT, ECMO, pneumothorax, very high BMI, pregnancy, or severe hemodynamic instability. EIT data will be used to quantify global and regional V/Q matching changes with each PEEP setting and compare responses between the low- and normal-compliance groups. The goal is to describe mechanistic differences in V/Q behavior that could explain variable gas-exchange responses to PEEP.

Who should consider this trial

Good fit: Ideal candidates are adults with moderate-to-severe ARDS (PaO2/FiO2 ≤200 at PEEP 5 cmH2O), intubated and deeply sedated on controlled mechanical ventilation between 24 hours and 5 days after intubation, who have no contraindication to EIT.

Not a fit: Patients with pneumothorax, ongoing ECMO, severe chest wounds preventing EIT, BMI ≥35 kg/m2, pregnancy, legal protection status, or persistent hypotension (MAP <60 mmHg) are excluded and would not benefit from participation.

Why it matters

Potential benefit: If successful, this approach could help tailor PEEP settings to a patient’s lung mechanics to improve oxygenation and reduce ventilator-related harm.

How similar studies have performed: EIT has previously been used to map ventilation and perfusion and to show heterogeneous PEEP responses, but using elastance-defined compliance phenotypes to guide PEEP is relatively novel with limited prospective outcome data.

Eligibility criteria

Show full inclusion / exclusion 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.

Where this trial is running

Angers, Maine et Loire

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: ARDS, pulmonary perfusion, ventilation-perfusion mismatch, compliance, recruitability

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.