What is a common pathophysiological feature of ARDS?

A common pathophysiological feature of Acute Respiratory Distress Syndrome (ARDS) is alveolar edema. In ARDS, the alveoli, which are the tiny air sacs in the lungs where gas exchange occurs, become flooded with fluid due to increased permeability of the pulmonary capillaries. This flooding leads to a reduction in the surface area available for gas exchange, ultimately resulting in hypoxemia and respiratory failure.

The presence of alveolar edema is a direct result of the underlying inflammatory process that characterizes ARDS. Various triggers, such as pneumonia, sepsis, or trauma, can lead to the release of inflammatory mediators. These mediators increase the permeability of the blood-gas barrier, allowing fluid and proteins to leak into the alveoli, causing them to fill with fluid instead of air.

The consequences of this edema include impaired oxygenation, decreased lung compliance, and difficulty in ventilating the lungs, all of which contribute to the clinical picture of ARDS. Thus, alveolar edema is central to understanding the pathophysiology and clinical management of this syndrome.