ARDS

Acute Respiratory Distress Syndrome (ARDS) is a severe, diffuse form of acute lung injury. Inflammation makes the alveolar-capillary barrier abnormally leaky, so protein-rich fluid enters the alveoli. Surfactant is lost, alveoli collapse, and the remaining aerated lung becomes stiff and vulnerable to ventilator injury. The result is severe hypoxemia that may not correct with supplemental oxygen alone because blood continues to flow through flooded, unventilated lung units. ARDS is not primarily cardiogenic pulmonary edema and requires critical-care management. The Berlin definition requires all of the following: - Onset within 1 week of a known clinical insult or new or worsening respiratory symptoms - Bilateral opacities on chest imaging that are not fully explained by pleural effusion, collapse, or pulmonary nodules - Respiratory failure not fully explained by cardiac failure or fluid overload - Impaired oxygenation measured while receiving PEEP or CPAP of at least 5 cm H2O Berlin severity is based on the PaO2/FiO2 ratio: - Mild: greater than 26.7–40.0 kPa - Moderate: greater than 100 to 200 mmHg - Severe: 100 mmHg or less Common triggers include...