Acute respiratory distress syndrome natural history

Overview
ARDS usually occurs within 24 to 48 hours of the initial injury or illness. Failure to treat the condition may result in life-threatening complications.

Natural History
Atrial septal defect If the underlying disease or injurious factor is not removed, the amount of inflammatory mediators released by the lungs in ARDS may result in a systemic inflammatory response syndrome (or sepsis if there is lung infection). The evolution towards shock and/or multiple organ failure follows paths analogous to the pathophysiology of sepsis.

This adds up to the impaired oxygenation, the real mainstay of ARDS, and respiratory acidosis, often caused by the ventilation techniques indicated in ARDS.

The result is a critical illness in which the 'endothelial disease' of severe sepsis/SIRS is worsened by the pulmonary dysfunction, which further impairs oxygen delivery.

Complications
Since ARDS is an extremely serious condition which requires invasive forms of therapy it is not without risk. Complications to be considered are:
 * Pulmonary: barotrauma (volutrauma), pulmonary embolism (PE), pulmonary fibrosis, ventilator-associated pneumonia (VAP).
 * Gastrointestinal: hemorrhage (ulcer), dysmotility, pneumoperitoneum, bacterial translocation.
 * Cardiac: arrhytmias, myocardial dysfunction.
 * Renal: acute renal failure (ARF), positive fluid balance.
 * Mechanical: vascular injury, pneumothorax (by placing pulmonary artery catheter), tracheal injury/stenosis (result of intubation and/or irritation by endotracheal tube.
 * Nutritional: malnutrition (katabolic state), electrolyte deficiency.