Progressive Care Nursing Certification (PCCN) Practice Exam

What happens if a pulmonary embolus occludes a small pulmonary artery?

1. Pneumonia develops

2. Pulmonary infarction may occur

3. Renal failure occurs

4. Compensatory respiratory rate increases

The correct answer is: Pulmonary infarction may occur

When a pulmonary embolus occludes a small pulmonary artery, it can lead to pulmonary infarction. This occurs because the blockage prevents blood from flowing to the lung tissue beyond the obstruction, resulting in ischemia and subsequent tissue death in that area. The lung tissue requires a continuous blood supply for oxygenation and nourishment; when an embolus interrupts this flow, the affected lung segment can suffer damage. Pulmonary infarction is characterized by symptoms such as pleuritic chest pain, hemoptysis (coughing up blood), and sometimes fever due to inflammation in the surrounding tissues. It's important to recognize that while the blockage of a small pulmonary artery primarily impacts the lung tissue supplied by that artery, the consequent effects can ripple throughout the pulmonary system and even affect overall oxygenation. The other outcomes listed do not directly result from an occlusion of a small pulmonary artery. While compensatory mechanisms such as an increased respiratory rate may occur in response to diminished oxygen exchange, it's not a direct result of the embolization itself. The development of pneumonia or renal failure is also not typically associated with the blockage of pulmonary arteries by emboli.