Detailed Description:

Respiratory failure is a common condition that requires prompt diagnosis and treatment in the emergency department. Diaphragmatic dysfunction (DD) is a potential contributor to respiratory failure, but it is often underdiagnosed and undertreated. Point-of-care ultrasound (POCUS) is a non-invasive and feasible tool that can measure diaphragmatic function using parameters such as diaphragm excursion and diaphragm shortening fraction (DSF). However, the prognostic value of POCUS for DD in patients with respiratory failure is unclear. This study is a prospective observational cohort study that will enroll consecutive patients with respiratory failure who are admitted to the emergency department of a tertiary hospital. All patients will undergo POCUS examination of the diaphragm within 6 hours of admission by trained emergency physicians. The primary outcome will be the composite of mortality, intubation, or noninvasive ventilation failure within 30 days of admission. The secondary outcomes will include length of hospital stay, intensive care unit admission, and ventilator-free days. The association between POCUS parameters of diaphragmatic function and clinical outcomes will be analyzed using multivariate logistic regression and Cox proportional hazards models.}}