Clinical trial · Interventional
PEEP-induced Effects on Respiratory dRivE and EFfort
Unraveling PEEP-induced Effects on Respiratory dRivE and EFfort in Acute Hypoxemic Respiratory Failure: the REEF Study
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
Rationale: In patients with acute hypoxemic respiratory failure (AHRF), preserving spontaneous breathing during mechanical ventilation offers physiological benefits, but also carries risks. While spontaneous breathing improves gas exchange and limits diaphragm atrophy, strong inspiratory efforts may worsen lung and diaphragm injury. Balancing these factors requires refined and tailored strategies, such as the modulation of PEEP. However, the impact of PEEP on neural respiratory drive and inspiratory effort is very heterogenous, and these two entities have only been studied separately in limited subsets of patients and healthy subjects. Additionally, it remains unclear whether the major determinant of PEEP-induced changes in respiratory drive and effort is represented by variations in diaphragm geometry, lung compliance, or by the presence of expiratory muscles recruitment, which may counteract its effect. Objective: The primary objective is to determine the effect of PEEP on diaphragm neuromechanical efficiency (i.e. an index of neural respiratory drive and inspiratory effort) in patients with acute hypoxemic respiratory failure during invasive assisted mechanical ventilation. The secondary objective is to determine the major physiological contributors to PEEP-mediated changes in diaphragm neuromechanical efficiency. Study design: Prospective, physiological study. Study population: Invasively mechanically ventilated adult patients admitted to the ICU. Intervention: For each patient, six different PEEP levels (15-12-10-8-5-2 cmH2O) will be tested during a decremental PEEP trial. During each step, neural respiratory drive, inspiratory effort, expiratory muscle activity, lung inflation pattern through electrical impedance tomography, respiratory muscle geometry and function through ultrasound and surface EMG, gas exchange and hemodynamics data will be collected. Main study parameters/endpoints: The primary outcome of the study will be the evaluation of PEEP-mediated changes in diaphragm neuromechanical efficiency (NME).
Conditions
Conditions (2)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Acute Hypoxemic Respiratory Failure | — | UNRESOLVED | — |
| ARDS (Moderate or Severe) | — | UNRESOLVED | — |
Interventions
Interventions (1)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| PEEP level changes | Other | — | UNRESOLVED |
Design
Arms and outcomes
Arms (1)
- type
- EXPERIMENTAL
- label
- Single arm
- interventionNames
- Other: PEEP level changes
Primary outcomes (1)
- measure
- PEEP-related changes in diaphragm neuromechanical efficiency (NME)
- timeFrame
- Measurements will be conducted throughout the protocol at each of the 6 PEEP levels tested: 15, 12, 10, 8, 5 and 2 cmH2O. Each PEEP step will last 30 minutes, and measurements will be collected recording the last 10 minutes of each step.
- description
- The primary endpoint of this study will be the evaluation of PEEP-induced changes in diaphragm neuromechanical efficiency (NME, cmH2O/µV), calculated as the ratio between the change in transdiaphragmatic pressure (representing inspiratory effort in cmH2O and assessed through the use of esophageal and gastric manometry) and the change in diaphragm electrical activity (neural respiratory drive, expressed in µV and measured through diaphragm EMG by a dedicated nasogastric tube) for each inspiration (ΔPdi/ΔEAdi). NME is an index of diaphragm efficiency and of potential electromechanical uncoupling, a key PEEP-mediated effect on the diaphragm. Its assessment combines changes in neural respiratory drive and inspiratory effort after a change in PEEP, which will be assessed individually and combined as a ratio as primary outcome.
Eligibility
Eligibility (as posted)
- Sex
- All
- Minimum age
- 18 Years
Show eligibility criteria text
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).
References
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