Evaluation of Airway Pressure Release Ventilation in COVID-19 ARDS

Lung protective mechanical ventilation is the cornerstone of ARDS management, reducing the work of respiratory muscles and optimizing gas exchange. However, it can be the source of deleterious effects, grouped under the terms of ventilator induced lung injury (VILI) and ventilator induced diaphragm dysfunction.

The protective ventilatory strategy has led to a significant improvement in the prognosis of ARDS patients, by reducing the volume of the air and oxygen mixture (lower tidal volume) delivered to the lungs and thus reducing the pulmonary stress and strain. However, this protective ventilation usually requires deep sedation and neuromuscular blockade to avoid deleterious patient-ventilator asynchrony.

Airway Pressure Release Ventilation (APRV) has been proposed to reduce patient-ventilator asynchrony and reduce the VILI. The operating principles of APRV are based on the presence of two pressure levels that are kept constant. Spontaneous breathing is possible at any time at both pressure levels if the patient is not deeply sedated or under neuromuscular blockade.

The investigators hypothesize that APRV mode could be beneficial on oxygenation and respiratory work in patients with ARDS secondary to SARS-COV2 viral pneumonia.

Inclusion criteria

• Patients treated in Nancy University Hospital between 01/04/2020 and 31/06/2020 for COVID-19 ARDS, requiring invasive ventilation
• Trial of airway pressure release ventilation during the ICU stay

Exclusion criteria

• Patients requiring veno-venous ECMO
• Patients unable to complete the 6-hour APRV trial due to poor tolerance : SpO2 decrease < 90% on FiO2 70%, haemodynamic instability (MAP < 65mmhg without vasopressors, or 0.5 mg/h increase in norepinephrine, ventilator asynchrony (respiratory rate >35), hypercapnia (pH < 7,25 or PaCO2 >60mmHg)