Summer Clinical Practice Test

High-frequency chest wall oscillation (HFCC) therapy uses which mechanism?

It uses a chest cuirass to generate biphasic changes in trans-respiratory pressure difference. It reduces sputum production. It has no impact on airway clearance in cystic fibrosis. It relies on endotracheal suctioning to clear secretions.

Correct Answer:

It uses a chest cuirass to generate biphasic changes in trans-respiratory pressure difference.

Explanation:

High-frequency chest wall oscillation works by delivering rapid, small-amplitude oscillations to the chest wall through a cuirass or inflatable vest. These quick pressure swings create biphasic changes in the transpulmonary (trans-respiratory) pressure difference, driving oscillatory airflow in the airways. That mechanical energy shears mucus from the airway walls and reduces its viscosity, helping secretions mobilize toward larger airways so they can be coughed up or suctioned. It enhances airway clearance, not by reducing mucus production, and it doesn’t rely on suctioning.

Access more questions from this quiz

Continue to Summer Clinical Practice Test for more practice questions and the full quiz experience.

Access More Questions