Certified Pulmonary Function Technologist (CPFT) Practice Exam

The method used to measure Total Lung Capacity (TLC) is body plethysmography. This technique provides a reliable way to measure the lung volumes, including the Total Lung Capacity, which represents the maximum amount of air the lungs can hold.

Body plethysmography works by placing a patient in an airtight chamber and measuring changes in pressure, which allows for an accurate calculation of lung volume based on changes in thoracic volume during breathing. This method not only accounts for trapped air in the lungs but is also less influenced by factors such as patient effort, making it especially valuable for assessing lung volumes in various clinical populations.

While spontaneous spirometry measures dynamic lung volumes like Forced Vital Capacity (FVC) and Forced Expiratory Volume (FEV1), it does not accurately measure Total Lung Capacity, particularly for patients with obstructive lung disease where lung volumes may be significantly elevated due to air trapping.

Carbon monoxide diffusing capacity assesses how well oxygen and carbon monoxide are transferred from the lungs to the blood, but it does not provide information about overall lung volume.

Pneumotachography is primarily used for measuring airflow rates and can provide dynamic respiratory parameters but does not give a direct measure of Total Lung Capacity.

Thus, body plethysm