Adult Critical Care Specialty (ACCS) Practice Exam

What characterizes the exudative phase of ARDS?

1. Development of scar tissue in lungs

2. Capillary permeability increases allowing fluid into alveoli

3. Surfactant levels rise significantly

4. Pulmonary hypertension begins

The correct answer is: Capillary permeability increases allowing fluid into alveoli

The exudative phase of Acute Respiratory Distress Syndrome (ARDS) is primarily characterized by increased capillary permeability. This physiological change allows fluid, including proteins and inflammatory cells, to leak from the pulmonary capillaries into the alveoli. The accumulation of this fluid in the alveolar spaces disrupts normal gas exchange, leading to hypoxemia and respiratory distress. During this phase, which occurs within the first week of ARDS, there is also an inflammatory response that further exacerbates lung injury. The presence of fluid in the alveoli can manifest as pulmonary edema on imaging and can be assessed through clinical findings such as decreased lung compliance and impaired oxygenation. In contrast, the development of scar tissue, or fibrosis, occurs in a later phase of ARDS known as the organizing phase, where there is repair and remodeling of lung tissue. Surfactant levels typically decrease during the exudative phase, not rise, which can lead to alveolar collapse and atelectasis. Although pulmonary hypertension can develop in various contexts, its onset is not specific to the exudative phase and often results from other factors related to lung injury and hypoxemia rather than being a defining characteristic of this initial phase.