Acute Respiratory Distress Syndrome (ARDS) is a syndrome of inflammation and increased permeability associated with a constellation of clinical, radiologic, and physiologic abnormalities unexplained by elevations in left atrial or pulmonary capillary pressure.

All definitions of this syndrome include patients who meet the following criteria: Identifiable associated condition Acute onset Pulmonary artery wedge pressure </=18 mm Hg or absence of clinical evidence of left

atrial hypertension Bilateral infiltrates on chest radiography Acute lung injury (ALI) is present if Pao2/Fio2 ratio is </= 300 Acute respiratory distress syndrome is present if Pao2/Fio2 ratio </= 200

ARDS = acute respiratory distress syndrome; Pao2 = partial pressure of arterial oxygen; Fio2 = percentage of inspired oxygen.

Clinical Conditions Associated with Development of Acute Respiratory Distress Syndrome

Direct lung injury Pneumonia Aspiration of gastric contents Inhalation injury Near drowning Pulmonary contusion Fat embolism Reperfusion pulmonary edema post lung transplantation or pulmonary embolectomy

Indirect lung injury Sepsis Severe trauma Acute pancreatitis Cardiopulmonary bypass Massive transfusions Drug overdose