Hypoxemic acute respiratory failure is one of the main COVID-19 patients complication that lead to in intensive care hospitalization.

This complication determines a variable mortality from 25 to 30%. To correct hypoxemia (often severe) is often needed non-invasive or invasive mechanical ventilation.

Mechanical ventilation is not a therapeutic strategy, but it allows to extend the time-to-recovery necessary to solve COVID-19 respiratory failure cause.

Calibration of ventilatory support is essential to ensure adequate time-to-recovery without contributing to onset lung and / or diaphragmatic damage.

Basal diaphragmatic activity assessment, device for administering the oxygenation support choice and setting ventilatory support parameters are decisive.

Ultrasound is the best method for measuring diaphragmatic work. The aim of this study is to evaluate the diaphragmatic thickening fraction in COVID-19 patients admitted to Intensive Care Unit (ICU) for acute respiratory failure and to record its function on weaning.

Hypoxemic acute respiratory failure in COVID-19 patients often leads to necessity of intubation and mechanical ventilation support. Complications may be severe as Ventilator-Induced Lung Injury (VILI) and respiratory infections. Weaning process from mechanical ventilation is based on respiratory work reduction and mechanical support to allow patient's respiratory ability to recovery. Respiratory muscle strength give an important contribute. Ultrasound diaphragmatic evaluation is essential to evaluate patients respiratory capacity as diaphragm atrophy usually suggest a difficult process and weaning failure.

COVID-19 pneumonia represent a particular type of ARDS (acute respiratory distress syndrome), in which different mechanism such as interstitial edema and diffuse alveolar damage, ventilation-perfusion mismatch, intrapulmonary shunt play a role/attend The aim of this study is to assess diaphragmatic function in weaning from mechanical ventilation in patients affected from COVID-19 respiratory failure and his implications.

Inclusion Criteria:

• Hypoxemic respiratory failure in COVID-19 patients during intensive care unit hospitalization
• Age> 18 years
• Weaning by mechanical ventilation

Exclusion Criteria:

• tracheostomy,
• unstable clinical conditions;
• agitation (Richmond Agitation-Sedation Scale (RASS)≥ + 2) or non-cooperation (Kelly Matthay scale ≥5);
• more than two organ failure
• consent refusal

Patients with severe hypoxemic covid-related respiratory failure admitted to intensive care unit in Udine and five other centers. These subjects required mechanical ventilation during hospitalization.