PEEP levels and breathing effort during assisted mechanical ventilation

Impact of Positive End-Expiratory Pressure on the Modulation of Respiratory Effort During Assisted Ventilation: A Physiological Randomized Crossover Study

This trial tests whether changing PEEP levels can reduce excessive breathing effort in adults receiving assisted mechanical ventilation in the ICU.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 12 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Pontificia Universidad Catolica de Chile (Academic / other)
• Locations: 1 site (Santiago, Santiago Metropolitan)
• Trial ID: NCT07437846 on ClinicalTrials.gov

What this trial studies

This is a randomized crossover physiological trial that applies four predefined PEEP levels to adults on assisted invasive mechanical ventilation and compares breathing effort and respiratory mechanics across those settings. Participants are clinically stable ICU patients with spontaneous breathing who can tolerate protocolized PEEP changes. Measurements likely include inspiratory effort (for example via esophageal pressure), ventilator waveforms, and lung mechanics at each PEEP level. The goal is to characterize how PEEP directly influences inspiratory drive and potential risk of lung or diaphragmatic injury during assisted ventilation.

Who should consider this trial

Good fit: Adults (≥18 years) in the ICU receiving invasive assisted mechanical ventilation with spontaneous effort, clinically stable for PEEP adjustments, and able to provide informed consent or have a legal representative do so.

Not a fit: Patients who are apneic, deeply sedated or paralyzed, hemodynamically unstable, pregnant, have contraindications to esophageal balloon placement, or have neurological conditions that blunt respiratory drive are unlikely to benefit.

Why it matters

Potential benefit: If successful, the trial could identify PEEP settings that reduce harmful inspiratory effort and help lower the risk of patient self-inflicted lung or diaphragmatic injury during assisted ventilation.

How similar studies have performed: Previous physiologic studies show PEEP can change lung mechanics and inspiratory effort, but its direct effects during assisted spontaneous breathing are not well established and findings have been mixed.

Eligibility criteria

Inclusion criteria:

* Age ≥18 years.
* ICU patients receiving invasive mechanical ventilation (endotracheal tube or tracheostomy).
* Ventilated in an assisted mode with spontaneous breathing
* Clinically stable to undergo protocolized PEEP changes.
* Sedation level compatible with spontaneous breathing and ventilator triggering
* Informed consent from the patient or legally authorized representative.

Exclusion Criteria:

* Contraindication to esophageal balloon placement (if applicable).
* Significant hemodynamic instability or unstable vasopressor requirements.
* Unstable arrhythmia or active myocardial ischemia.
* Undrained pneumothorax or major air leak.
* Controlled ventilation without effective spontaneous effort (apnea, neuromuscular blockade, deep sedation).
* Pregnancy
* Acute or chronic neurological conditions that may impair respiratory drive or interfere with the regulation of spontaneous breathing.

Where this trial is running

Santiago, Santiago Metropolitan

• Hospital Clinico UC — Santiago, Santiago Metropolitan, Chile (Recruiting)

Study contacts

• Principal investigator: Roque Basoalto, PhD, Msc, Physioterapy — Pontifica Universidad Catolica de Chile
• Study coordinator: Diego Lopez Arnello, Physioterapy

Conditions Mechanical Ventilation; Respiratory Failure; Effort; Assisted mechanical ventilation; Inspiratory Effort; Breathing effort