How changing PEEP affects breathing drive and effort during pressure‑support ventilation

Unraveling PEEP-induced Effects on Respiratory dRivE and EFfort in Acute Hypoxemic Respiratory Failure: the REEF Study

Not applicable Interventional Radboud University Medical Center · NCT07203781

We will test whether changing PEEP levels changes neural respiratory drive and inspiratory effort in adults on pressure‑support ventilation for moderate‑to‑severe ARDS or acute hypoxemic respiratory failure.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment20 (estimated)
Ages18 Years and up
SexAll
SponsorRadboud University Medical Center Academic / other
Locations1 site (Nijmegen, Gelderland)
Trial IDNCT07203781 on ClinicalTrials.gov

What this trial studies

This is an interventional physiologic protocol that changes positive end‑expiratory pressure (PEEP) in invasively ventilated adults with acute hypoxemic respiratory failure (PaO2/FiO2 ≤ 200) who are breathing with pressure support and have measurable inspiratory efforts. While patients remain on assisted ventilation, investigators will record neural and mechanical measures of breathing (for example EAdi, oesophageal pressure, and electrical impedance tomography) as PEEP is adjusted to observe short‑term effects. The protocol aims to define how PEEP alters neural respiratory drive and inspiratory effort and to explore whether these effects are driven by diaphragm geometry, lung compliance, or recruitment of expiratory muscles. Procedures are performed at a single center with advanced physiologic monitoring during brief PEEP interventions.

Who should consider this trial

Good fit: Adults over 18 with acute hypoxemic respiratory failure (PaO2/FiO2 ≤ 200) who are on invasive pressure‑support ventilation with valid spontaneous inspiratory efforts (occlusion pressure > 5 cmH2O) and who can tolerate EIT and oesophageal/EAdi monitoring are ideal candidates.

Not a fit: Patients with pre‑existing neuromuscular disease, chronic respiratory failure requiring long‑term oxygen, ongoing muscle paralysis, pneumothorax, or contraindications to EIT or oesophageal/EAdi catheter placement are unlikely to qualify or benefit.

Why it matters

Potential benefit: If successful, the results could help clinicians choose PEEP settings that reduce harmful inspiratory effort and better protect both lung and diaphragm function.

How similar studies have performed: Previous small physiologic studies in volunteers and limited patient groups have shown mixed and heterogeneous PEEP effects on drive and effort, so this detailed simultaneous‑measurement approach is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age \> 18 years
* Acute hypoxemic respiratory failure (AHRF) with a PaO2/FiO2-ratio ≤ 200
* Patient on invasive assisted mechanical ventilation in pressure support mode exhibiting valid inspiratory efforts (occlusion pressure \> 5 cmH2O).

Exclusion Criteria:

* Pre-existent neuromuscular disease
* History of chronic respiratory failure requiring long-term oxygen therapy
* Muscle paralysis
* Pneumothorax
* Contra-indication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode placement)
* Contra-indications for EAdi or oesophageal balloon catheter placement (e.g. history of gastric bypass surgery, gastro-oesophageal junction surgery, oesophageal stricture, recent upper gastrointestinal hemorrhage or known/suspected varices).

Where this trial is running

Nijmegen, Gelderland

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.
Conditions ARDSAcute Hypoxemic Respiratory FailurePEEPeffortdrivePSVpressure support ventilationAHRF
Last reviewed 2026-06-09 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.