Reproductibility of TM-mode Ultrasound Diaphragm Measures in Patients With Acute Respiratory Distress in the ER

Inclusion Criteria: * The patient must have given his/her informed and signed consent * The patient must be insured or beneficiary of a health insurance plan * The patient has acute respiratory distress defined by a respiratory rate \> 25, and / or signs of struggle and hypoxia, oxygen saturation (SpO2) \<90% and / or pH \<7.35 and carbon dioxide partial pressure (pCO2) \> 6 kPa (45 mm Hg) * The patient breathes spontaneously (no respirator) Exclusion Criteria: * The patient is participating in another study * The patient is in an exclusion period determined by a previous study * The patient is under judicial protection, under tutorship or curatorship * The patient or his/her representative refuses to sign the consent * It is impossible to correctly inform the patient, or to correctly inform his/her representative * The patient is pregnant, parturient, or breastfeeding * The patient has a neurological or neuromuscular disease that modifies diaphragm function/movement; this does not include cases of decompensation (polyradiculoneuropathy, Lou Gehrig's disease, Myasthenia ...). * Patient admitted with respiratory support treatment in progress * Patient admitted with respiratory failure requiring immediate implementation of mechanical ventilation, thus preventing ultrasound measurements