The diaphragm is a fine striated muscle with both extra respiratory and respiratory functions. It does most of the breathing work in interaction with the accessory respiratory muscles, the rib cage and the abdomen. Its activity can be measured by the transdiaphragmatic pressure generated by the magnetic stimulation of phrenic nerves (gold standard). It has been shown in the literature that diaphragmatic ultrasound, via the measurement of diaphragmatic excursion and especially the thickening fraction, is an easily accessible, non-invasive, reproducible and relevant technique for evaluating acute diaphragmatic dysfunction in resuscitation patients.

The objective of this project is to evaluate the prevalence of diaphragmatic dysfunction at admission in patients hospitalized in intensive care / respiratory intensive care unit for hypercapnic and/or hypoxic acute respiratory distress and requiring ventilatory support by non-invasive ventilation or high flow oxygen therapy. A subgroup analysis will then be carried out on 3 populations:

• Hypercapnic exacerbation of chronic obstructive pulmonary disease
• Hypoxic acute respiratory distress on infectious lung disease
• Acute pulmonary edema

Inclusion Criteria:

• Hospitalization for acute respiratory distress management
• Etiological diagnosis either:
• Exacerbation of chronic obstructive pulmonary disease
• Infectious pneumonitis
• Acute pulmonary edema
• Need for a ventilatory support by either:
• Non-invasive ventilation
• High flow oxygen therapy (flow rate > 40L/min and oxygen inspired fraction > 40%)
• Mask oxygen therapy with flow rate > 5L/min

Exclusion Criteria:

• Exacerbation of interstitial pathology / pulmonary fibrosis
• Deformation of the thoracic cage
• Neurodegenerative pathology
• Need for oro-tracheal intubation from the beginning for mechanical ventilation
• Contraindication to Non-invasive Ventilation
• Patients undergoing diaphragmatic rehabilitation
• Immunocompromised patients
• History of known diaphragmatic dysfunction