Acute dyspnea is a common cause of emergency department admissions among elderly patients. Acute respiratory failure is often multifactorial and requires rapid and reliable evaluation. Currently, management relies on clinical, biological, and radiological assessments, but diaphragmatic ultrasound could provide an additional tool for real-time respiratory function evaluation. This study aims to integrate this non-invasive technology into the initial assessment of patients to improve care pathways. Hypothesis : Diaphragmatic ultrasound enables reliable assessment of respiratory function and can predict the need for mechanical ventilation.

Inclusion Criteria:

• Patients aged ≥ 75 years
• Emergency admission for acute dyspnea
• Requiring an emergency ultrsoung.

Exclusion Criteria:

• Acute respiratory distress requiring immediate invasive or non-invasive ventilation
• Respiratory rate ≥ 25 breaths/min, and/or SpO2 ≤ 90% on room air, and/or PaO2 ≤ 60 mmHg
• Known diaphragmatic paralysis
• Patients with degenerative neuromuscular disease
• State of shock: systolic blood pressure < 90 mmHg and/or mean arterial pressure < 65 mmHg and/or presence of skin mottling and/or CTR > 3s
• Lactate levels > 2 mmol/L
• Hypercapnic respiratory acidosis (pH < 7.38 and PaCO2 > 45 mmHg)
• Dyspnea due to metabolic acidosis (e.g., diabetic ketoacidosis, renal failure)
• Dyspnea of traumatic origin
• Refusal to participate or inability to provide informed consent
• Patients deprived of liberty
• Patients under guardianship or curatorship

Patients Aged 75 and Over Admitted to the Emergency Department for Acute Dyspnea