New York City Certified First Responder – Defibrillation (CFR-D) Practice Exam

Wheezing upon respiration is primarily caused by the narrowing or constriction of the lower airways, which can occur in various conditions such as asthma, bronchitis, or other obstructive airway diseases. This narrowing leads to turbulent airflow, producing a high-pitched whistling sound during exhalation or sometimes during inhalation.

When considering the other options, a hemothorax and pneumothorax are related to fluid or air accumulation in the pleural space, which typically manifests with different symptoms such as sharp chest pain and difficulty breathing but does not directly cause wheezing. A sucking chest wound, a type of open pneumothorax, can also obstruct normal airflow, but it does not specifically lead to the narrow airway conditions that generate wheezing sounds. Therefore, the correct choice focuses on the physiological mechanism behind wheezing, which is fundamentally based on airway constriction.