ARDS - A clinical syndrome that includes pulmonary insufficiency. ARDS is a descriptive term that is applied to a variety of diffuse infiltrative processes in the lung. Manifestations include severe shortness of breath, rapid breathing, and arterial hypoxemia (low oxygen). Chest x-ray shows bilateral diffuse infiltrates. Treatment most often includes mechanical respiratory support. Causes include toxic gas (chlorine, NO2, smoke) exposure, severe metabolic derangement, gastric acid aspiration, pancreatitis, sepsis, and trauma.