Which of the following conditions is least likely to lead to decreased lung compliance?

Decreased lung compliance refers to the reduced ability of the lungs to stretch and expand, which can be influenced by various respiratory conditions. Among the listed options, asthma is least likely to lead to decreased lung compliance.

Asthma is characterized primarily by airway obstruction due to bronchoconstriction, inflammation, and increased mucus production rather than significant changes in lung tissue elasticity or volume. During an asthma attack, the lungs may feel tight, but the compliance can actually remain relatively normal unless there is significant air trapping, which is less common compared to the other conditions mentioned.

In contrast, conditions like ARDS, pneumonia, and pulmonary edema typically lead to decreased lung compliance. ARDS causes stiffening of the lungs due to severe inflammation and fluid accumulation in the alveoli, which greatly impacts how easily the lungs can expand. Pneumonia involves infection and inflammation, leading to consolidation and loss of normal lung architecture, contributing to decreased compliance. Pulmonary edema, often stemming from heart failure or other conditions, results in fluid accumulation in the alveoli, also impairing the lung's ability to expand normally.

Thus, asthma stands out as the condition that is least likely to significantly affect lung compliance compared to the more mechanical and structural issues presented by the other options.