Certified Pulmonary Function Technologist (CPFT) Practice Exam

The correct choice is based on the fact that a spirometer's primary function is to measure the volume of air that a patient can inhale and exhale, as well as the flow rate of air during these respiratory activities.

When assessing lung function, clinicians need to know how much air is moving in and out of the lungs (volume) and the speed at which this air movement occurs (flow). These two parameters are critical in diagnosing and monitoring respiratory conditions, making them essential measurements derived from spirometry.

Volume refers to the amount of air inhaled or exhaled, which is crucial in understanding lung capacity and potential restrictions. Flow measures how quickly this air is being pushed out or taken in, offering insights into the airway's status.

The other options involve measurements that are not directly assessed by standard spirometry. Time and pressure, while they may play a role in respiration and pulmonary function measurements, are not the key outputs of spirometry. Pressure and resistance, as well as resistance and capacitance, are more relevant in other forms of pulmonary testing but not specifically in the direct measurements provided by a spirometer. Hence, the focus on volume and flow accurately reflects the primary data captured during spirometric assessments.