NEW CONCEPTS IN SUPPORTING ACUTE LUNG INJURY

Abstract

The most sever form of acute lung injury (ALI) is the acute respiratory distress syndr0me (ARDS). It is a syndrome of alveoler-cappillary inflammation and increased cappillary permeability associated with clinical, radiologic and physiological abnormalities. ARDS is triggerd by an injury that may not involve the lung initially but as a part of systemic inflammatory response syndromeie sepsis syndrome, aspiration, pulmonary pneumonia ...etc. It is acute in onset and persistent ie lasting days to weeks, associated with one or more risk factors and characterized by arterial hypoxemia refractory to oxygen therapy alone and diffuse radiologic infiltrates. Structural response to injury includes exudative, early proliferative and late proliferative phases and the physiologic changes include gas exchange abnormalities with the earliest abnormality, the hypoxemia due to atelectasis and alveoler flooding with resultant venoarterial shunting of blood. Other changes are reduced lung compliance and pulmonary hypertension • with surfactant dysfunction due to loss from airways with mechanical ventilation, disturbed synthesis.