A 65-year-old woman with a smoking history of 2 packs/day for 30 years has received a diagnosis of chronic obstructive lung disease.She is obviously using her accessory respiratory muscles for breathing; this behavior is caused by:
A)Decreased work of breathing as a result of airflow obstruction.
B)Increased work of breathing as a result of a dysfunction in the neuromuscular junction.
C)Increased work of breathing as a result of airflow obstruction that necessitates active contraction of the expiratory muscles.
D)Abnormal breathing pattern.
E)Increased work of breathing as a result of airflow obstruction that necessitates active contraction of the inspiratory muscles.

Question

Quizplus · Accepted Answer

The use of accessory respiratory muscles is a compensatory mechanism utilized to overcome airflow obstruction in chronic obstructive lung disease. This requires active contraction of the expiratory muscles to assist with exhalation, resulting in increased work of breathing. Option A is incorrect as decreased work of breathing is not seen in patients with chronic obstructive lung disease. Option B is incorrect as dysfunction in the neuromuscular junction is not the cause of the use of accessory respiratory muscles. Option D is incorrect as abnormal breathing patterns can occur in various conditions, but this does not explain the specific mechanism seen in chronic obstructive lung disease. Option E is incorrect as active contraction of the inspiratory muscles is not needed to overcome airflow obstruction in chronic obstructive lung disease.

A 65-Year-Old Woman with a Smoking History of 2 Packs/day