Which of the following is the most common cause of Acute Respiratory Distress Syndrome?

The most common cause of Acute Respiratory Distress Syndrome (ARDS) is sepsis. Sepsis triggers a systemic inflammatory response that can lead to increased permeability of the alveolar-capillary membrane, resulting in pulmonary edema and impaired gas exchange characteristic of ARDS. The inflammatory mediators released during sepsis can damage the lung tissue directly, compounded by infections that often cause sepsis, such as pneumonia or abdominal infections.

While aspiration, pneumonia, and severe trauma are all significant contributors to ARDS, they individually account for a smaller proportion of cases compared to sepsis. Aspirated material may cause lung injury and pneumonia can lead to ARDS as a secondary effect, but the direct systemic effects of sepsis on the lungs make it the predominant cause within the broader clinical context of ARDS. Hence, in evaluating the leading cause among the options, sepsis stands out as the primary trigger.