<unk>  <unk>   is a diffuse heterogeneous lung<unk>  characterized by hypoxemia, non cardiogenic pulmonary edema, low lung compliance and widespread capillary leakage. <unk>  is caused by any stimulus of local or systemic inflammation, principally sepsis.<unk>  <unk>  & Acute Respiratory Distress Syndrome (ARDS) are defined as:
Bilateral pulmonary infiltrates on chest x-ray
Pulmonary Capillary Wedge Pressure <18mmHg
PaO2/FiO2* <300 =<unk> 
PaO2/FiO2 <200 = ARDS
Primary<unk>  is caused by a direct<unk>  to the lung (e.g. pneumonia). Secondary<unk>  is caused by an indirect insult (e.g. pancreatitis).  There are two stages – the acute phase characterized by disruption of the alveolar-capillary interface, leakage of protein rich fluid into the interstitium and alveolar space and extensive release of cytokines and migration of neutrophils. A later reparative phase is characterized by fibroproliferation, and organization of lung tissue.
The patient has low lung volumes, atelectasis, loss of compliance, ventilation-perfusion mismatch (increased deadspace) and right to left shunt.
Clinical features are - severe dyspnea, tachypnea and resistant hypoxemia. There are two diagnoses to be made: the syndrome of<unk>  and the underlying cause.<unk>  is a clinical diagnosis. There are probably two forms of<unk>  – primary<unk> , caused by a direct<unk>  to the lung, and secondary<unk> , caused by an indirect<unk>  to the lung. The cornerstone of treatment is to keep the PaO2 >60mmHg, without causing<unk>  to the lungs with excessive O2 or volutrauma.
Pressure control ventilation is more versatile than volume control: but a volume limited strategy should be used. A number of adjunct therapies are available, none have proven effective. Of these, inhaled nitric oxide and prone positioning are most frequently used. Current ventilation strategies involve using low tidal volumes with or without high levels of PEEP. The open lung approach attempts to optimize lung mechanics and minimize phasic damage by strategically placing PEEP above Pflex.  Ventilator induced lung<unk>  is caused by volutrauma and excessive use of oxygen.
Steroids may have a role in chronic ARDS in patients, without infection, with high O2 requirements days to weeks into the disease process.
Acute lung injury
Acute respiratory distress syndrome
Aspiration pneumonia
Trapped lung
Ventilator-associated lung injury
Acute chest syndrome
Chemical pneumonitis
Fat embolism syndrome