Avalanche Phenomenon During Airways Opening in Acute Respiratory Distress Syndrome

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Total Enrollment

50 participants

Study Classification

OBSERVATIONAL

Study Start Date

2022-03-01

Study Completion Date

2026-10-31

Brief Summary

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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.

Detailed Description

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Conditions

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Acute Respiratory Distress Syndrome

Study Design

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Observational Model Type

COHORT

Study Time Perspective

PROSPECTIVE

Interventions

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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.

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* Age ≥ 18
* Moderate-to-severe acute respiratory distress syndrome within the first 72 hours after meeting the Berlin definition criteria:
* Within 1 week of a known clinical insult or new or worsening respiratory symptoms;
* Bilateral opacities (not fully explained by effusions, lobar/lung collapse, or nodules);
* Respiratory failure not fully explained by cardiac failure or fluid overload;
* PaO2/FiO2 ≤ 200 mmHg with positive end-expiratory pressure ≥ 5 cmH2O.
* Absence of spontaneous breathing efforts
* Consent to participate to the study from the patient and/or its surrogate

Exclusion Criteria

* Pneumothorax
* Broncho-pleural fistula
* Tracheostomy
* Hemodynamic instability
* Severe hypoxemia
* Suspected of proven intracranial hypertension
* Chronic obstructive lung disease
* Pacemaker or defibrillator
* Decision to withhold of withdraw life-sustaining measures
* Under protection

Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Responsible Party

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Responsibility Role SPONSOR

Locations

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CHU Poitiers

Poitiers, , France

Site Status RECRUITING

Countries

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France

Central Contacts

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Rémi Coudroy, MD, PhD

Role: CONTACT

Phone: + 33 5 49 44 40 07

Email: [email protected]

Céline DELETAGE

Role: CONTACT

Phone: +33 5 49 44 38 54

Email: [email protected]

Facility Contacts

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Rémi COUDROY, Pr

Role: primary

References

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Suki B, Barabasi AL, Hantos Z, Petak F, Stanley HE. Avalanches and power-law behaviour in lung inflation. Nature. 1994 Apr 14;368(6472):615-8. doi: 10.1038/368615a0.

Reference Type BACKGROUND

PMID: 8145846 (View on PubMed)

Chen L, Del Sorbo L, Grieco DL, Shklar O, Junhasavasdikul D, Telias I, Fan E, Brochard L. Airway Closure in Acute Respiratory Distress Syndrome: An Underestimated and Misinterpreted Phenomenon. Am J Respir Crit Care Med. 2018 Jan 1;197(1):132-136. doi: 10.1164/rccm.201702-0388LE. No abstract available.