Evaluation of the Relevance of Diaphragmatic Stroke Ultrasound for the Etiological Diagnosis of Acute Respiratory Distress in an Emergency Department.

The goal of this Prospective interventional multicenter diagnostic study is to investigate the use of diaphragmatic ultrasound (DE) as a diagnostic tool in an adult emergency department for patients in acute respiratory distress.

The main question it aims to answer is to evaluate the relevance of measuring the Sum of Plateau Times (SPT) by Clinical Ultrasound in Emergency Medicine (CHEM) for the diagnosis of pneumopathy during acute respiratory distress (ARD) in the Emergency Department.

Secondary objectives include the study of other diaphragmatic ultrasound parameters, inspiratory plateau time (IPT) and expiratory plateau time (EPT), and the diagnostic relevance of PTS for the diagnosis of decompensation of Chronic obstructive pulmonary disease (BPCO) and acute cardiogenic pulmonary edema (APO).

Each eligible patient will have a right diaphragmatic ultrasound performed by a trained physician, then clinicobiological data will be collected later from medical records, and the etiological diagnosis will be established by a committee of 2 experts in the management of respiratory distress.

Diaphragmatic ultrasound (DE) has never been studied as a diagnostic tool in the emergency department. The sensitivity and specificity of pleural ultrasound for the diagnosis of pneumopathy is superior to that of chest radiography, with evidence of interstitial syndrome or unilateral pleural effusion, but it is not specific for infectious pneumopathy. Proving that diaphragmatic ultrasonography can be used to diagnose pneumopathy in respiratory distress, thanks to a specific index known as the Sum of Plateau Times (STP), will save time in patient management.

The secondary criteria of this study could be used in future studies, if they prove relevant.

Eligibility Criteria:
Inclusion Criteria:

* Patients 18 years of age or older;
* Patient with ARD defined by respiratory rate (RR) strictly superior to 25 and/or signs of struggle which are: thoraco-abdominal rocking, active abdominal breathing, recruitment of extra-diaphragmatic respiratory muscles AND
* peripheral saturation (SpO2) strictly inferior to 90% and/or hypercapnic acidosis (pH strictly inferior to 7.35 and pCO2 strictly superior to 45mmHg) on arterial blood gases;
* Spontaneous ventilation.
* Patients presenting a clinical severity score of Grade 1 with signs of struggle, as well as those with Grade 2 and Grade 3. A clinical severity score will be used as follows: Grade 1: Minimal polypnoea with respiratory rate (RR) between 20 and 25 ; Grade 2: Moderate polypnoea with respiratory rate (RR) between 25 and 35; Grade 3: Major polypnoea with respiratory rate (RR) between 35 to 50.

Exclusion Criteria:

* Adult protected by law (guardianship, curatorship, legal protection)
* Refusal of consent after information
* Patient on non-invasive ventilation ;
* Patient on mechanical ventilation;
* Respiratory rate superior to 50/min
* Patient currently being treated for infectious pneumopathy with antibiotics;
* Pregnant or breast-feeding women;
* Patients with any known history of diaphragmatic pathologies.
* Illiterate or unable to understand the purpose and methodology of the study.
* Patient not affiliated to a social security scheme or not benefiting from such a scheme.
* Person deprived of liberty (by judicial or administrative decision, or forced hospitalization)
* Person participating in another study with an exclusion period still in progress,