Multicenter Prospective Observational Study on Diaphragmatic Function Assessment by Ultrasound in Patients with Acute Respiratory Failure Receiving Non-invasive Mechanical Ventilation or High Flow Nasal Canula

"Sample:~Given the observational nature of the study, a convenience sample will be obtained from all patients admitted to the emergency services and/or ICU with respiratory failure over the course of 1 year.~Inclusion Criteria:~* Age ≥ 18 years~* Hypoxemic respiratory failure (SpO2 \< 88% - PaO2 \< 60 mmHg) or hypercapnic (PaCO2 \> 40)~* Need for NIMV and/or HFNC.~Exclusion Criteria:~* Neuromuscular disease~* Pregnancy~* Tracheostomy~* Rib fractures~* Cervical injuries~* Diaphragmatic paralysis~* Diaphragmatic malformations~* Hemodynamic instability~* Morbid obesity (BMI \> 35)~* Use of sedation and neuromuscular relaxants~* Pneumothorax or pneumomediastinum~* Poor acoustic window~* Critically ill patients with a prognosis of less than 24 hours of life~* Patients receiving palliative interventions."