What is defined as ARDS?

Acute Respiratory Distress Syndrome (ARDS) is characterized by rapid onset of respiratory failure, often in the setting of significant underlying lung pathology. The defining feature of ARDS is the presence of bilateral infiltrates on chest imaging, which typically indicates pulmonary edema caused by a variety of factors such as infection, trauma, or aspiration. This condition leads to reduced lung compliance and impaired gas exchange, manifested as severe hypoxemia.

In contrast, chronic lung conditions, such as those represented in other choices, do not align with the acute onset and the specific imaging findings associated with ARDS. Chronic obstructive pulmonary disease (COPD), for example, is a long-term condition characterized by progressive airflow limitation and does not present with the acute bilateral infiltrates seen in ARDS. Furthermore, conditions that lead to increased pulmonary artery pressure or minor lung injuries related to allergies do not meet the definition or presentation of ARDS. Understanding the unique presentation of ARDS helps differentiate it from other pulmonary conditions in clinical practice.