Emergency Medical Technician (EMT) Intermediate Practice Exam

Which description most accurately defines the pathophysiology of a pneumothorax?

1. Increased intrathoracic pressure

2. Intrapleural pressure with progressive pulmonary collapse

3. Decreased lung compliance

4. Airway obstruction

The correct answer is: Intrapleural pressure with progressive pulmonary collapse

A pneumothorax occurs when air enters the pleural space between the lung and the chest wall, which leads to a disruption in the negative pressure that normally keeps the lungs inflated. The pathophysiology involves a balance between atmospheric pressure and pleural pressure, and when air enters this space, it results in increased pressure within the pleural cavity. The correct description highlights how intrapleural pressure changes due to the presence of air in the pleural space, leading to progressive pulmonary collapse. As air accumulates, it creates a pressure that can cause the lung on the affected side to collapse partially or completely, inhibiting normal lung inflation and functionality. This reflects the mechanism behind the development and symptoms of pneumothorax, such as sudden shortness of breath and chest pain. Other options such as increased intrathoracic pressure, decreased lung compliance, and airway obstruction do not specifically define the pathophysiology of a pneumothorax as accurately. While they may relate to other respiratory conditions or complications, they do not encapsulate the essential dynamic of how air between the pleura disrupts lung expansion like the chosen description does.