Emergency Medical Technician (EMT) Intermediate Practice Exam

Which of the following is NOT a physiological effect of CPAP?

1. Improving pulmonary ventilation

2. Dispersing thick secretions within the lung tissue

3. Increasing functional residual capacity

4. Alleviating hypoxemia

The correct answer is: Dispersing thick secretions within the lung tissue

Continuous Positive Airway Pressure (CPAP) is a non-invasive ventilation strategy commonly used in emergency and critical care settings. Its primary role is to improve oxygenation and ventilation in patients with respiratory distress, particularly in conditions such as congestive heart failure or chronic obstructive pulmonary disease (COPD). Focusing on the physiological effects of CPAP, it is known for improving pulmonary ventilation by maintaining positive pressure in the airways, preventing airway collapse, and enhancing the exchange of gases. Increasing functional residual capacity is also a well-documented effect since CPAP helps to keep alveoli open, which can enhance the volume of air left in the lungs after expiration; this is especially beneficial during inspiratory efforts. While CPAP can indeed alleviate hypoxemia by improving oxygenation through better ventilation and expanded lung capacity, it does not directly disperse thick secretions within the lung tissue. That function typically requires specific airway clearance techniques, such as suctioning or using nebulized medications to thin secretions. Thus, the claim that CPAP directly disperses thick secretions is not accurate, making it the choice that does not represent a physiological effect of CPAP.