History
Acute respiratory distress syndrome was first described in 1967 by Ashbaugh et al. Initially there was no definition, resulting in controversy over incidence and mortality. In 1988 an expanded definition was proposed which quantified physiologic respiratory impairment.
In 1994 a new definition was recommended by the American-European Consensus Conference Committee. It had two advantages: first, it recognizes that severity of pulmonary injury varies, and secondly, it is simple to use.
ARDS was defined as the ratio of arterial partial oxygen tension (PaO2) as fraction of inspired oxygen (FiO2) below 200 mmHg in the presence of bilateralinfiltrates on the chest x-ray. These infiltrates may appear similar to those of left ventricular failure, but the cardiac silhouette appears normal in ARDS. Also, the pulmonary capillary wedge pressure is normal (less than 18 mmHg) in ARDS, but raised in left ventricular failure.
A PaO2/FiO2 ratio less than 300 mmHg with bilateral infiltrates indicatesacute lung injury (ALI). Although formally considered different from ARDS, ALI is usually just a precursor to ARDS.
In 2012 the Berlin Definition of ARDS was published this did away with the ALI/ARDS differentiation. It opts instead to classify ARDS as Mild, Moderate or severe.
Read more about this topic: Acute Respiratory Distress Syndrome
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