Time-motion-mode Ultrasound Diaphragm Measures in Patients With Acute Respiratory Distress in Emergency Department

Inclusion Criteria: * The patient has given informed consent (and signed the consent form) or, in case of an emergency situation, an investigator has committed to obtaining the consent of the patient as soon as his/her condition permits * Patient affiliated with or beneficiary of a health insurance plan * Acute Respiratory Distress (DRA) defined by: (1) respiratory rate \> 25 and/or signs of struggle and hypoxia AND (2) SpO2 values \< 90% and/or \[pH \< 7.35 and pCO2 \> 6 kPa (45 mm Hg)\] * Breathing spontaneously (no ventilation) Exclusion Criteria: * Patient currently participating in or having participated in another interventional study in the previous three months, or patient in an exclusion period determined by a previous study * Patient under judicial protection or any kind of guardianship * Refusal to sign the consent * Patient pregnant, parturient, or lactating * Neurological or neuromuscular disease modifying the operation of the diaphragm without any decompensation (Polyneuropathy, Lou Gehrig's disease, Myasthenia ...) * Patient who received mechanical ventilation at home * Patient who received treatment by mechanical ventilation during the pre-hospitalization care phase * Patient admitted with respiratory failure requiring immediate installation of a mechanical ventilation and thus not allowing the performance of two ultrasound measurements * Patient suffering from a pneumothorax