What lung mechanics are typically affected in ARDS?

In Acute Respiratory Distress Syndrome (ARDS), the primary alteration in lung mechanics is characterized by reduced lung compliance. Compliance refers to the ease with which the lung can expand during inhalation. In ARDS, the lung tissue becomes stiff due to inflammation, damage to the alveoli, and the accumulation of fluid in the interstitium and alveolar spaces. This leads to increased surface tension and a heterogeneous distribution of ventilation, making it more difficult for the lungs to inflate properly.

As a result, patients with ARDS often require higher pressures from mechanical ventilation to achieve adequate tidal volumes. This significant decrease in compliance is a hallmark feature of ARDS and emphasizes the challenges faced in managing these patients on mechanical ventilators.

In contrast, scenarios of increased or normal lung compliance would suggest different pathophysiological conditions, such as chronic obstructive pulmonary disease (COPD) or pulmonary fibrosis, respectively. Variable lung compliance is not typically described in ARDS since the compliance issues are primarily consistent due to the underlying lung injury. Thus, reduced lung compliance in ARDS is crucial for understanding the mechanical ventilation strategy and interventions necessary for these patients.