NCT05224323

Avalanche Phenomenon During Airways Opening in Acute Respiratory Distress Syndrome

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 50 (estimated)
• Sponsor: Poitiers University Hospital · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Acute respiratory distress syndrome accounts for 23% of mechanically ventilated patients and is associated with high mortality rate. Although life-saving, mechanical ventilation may worsen lung injury through two main mechanisms: lung overdistension and atelectrauma. Indeed, the cyclic opening and closure of airways during tidal ventilation may cause lung and bronchial injuries as suggested by animal models and autopsy findings. Complete airways closure has recently been described in 40% of patients with acute respiratory distress syndrome, and setting positive end-expiratory pressure above the airway opening pressure may limit atelectrauma. However, animal and mathematical models suggest that above the airway opening pressure, more distal airways open unevenly according to their own opening pressure, resulting in an "avalanche"-like phenomenon during lung inflation. This phenomenon has never been described in humans. A better understanding of the opening of airways in acute respiratory distress syndrome may help to limit ventilation-induced lung injury and to improve outcomes.

Conditions

• Acute Respiratory Distress Syndrome

Interventions

Type	Name	Description
OTHER	Airway pressure, flow, esophageal pressure, ventilation distribution	After informed consent, baseline characteristics of patients will be collected. Airway pressure, flow and esophageal pressure will be recorded using high sampling rate and ventilation distribution using electrical impedance tomography will be recorded during the study. The ventilator will be set at a positive end-expiratory pressure of 15 cmH2O during 10 minutes. Then, respiratory rate will be decreased to 8 breaths/min, and positive end-expiratory pressure will be decreased to 5 cmH2O over one breath to measure the recruited volume. Then, three low-flow inflation and deflation pressure-volume curves will be performed before resuming clinical ventilator settings. Patients will be followed until Day 28 after inclusion or ICU discharge. Maneuvers performed are part of the usual care of patients with acute respiratory distress syndrome in our unit.

Timeline

• Start date: 2022-03-01
• Primary completion: 2026-09-01
• Completion: 2026-10-01
• First posted: 2022-02-04
• Last updated: 2025-12-24

Locations

1 site across 1 country: France