CPFT Practice Questions
Prepare for CPFT with more than an answer.
- Level
- Specialty (entry-level pulmonary function technologist credential)
- Valid for
- 5 years (Credential Maintenance Program cycle)
Domains covered on the exam 3
- Instrumentation / Equipment33%
- Procedures44%
- Data Management23%
- 1
A patient's spirometry reveals an FEV1/FVC ratio below the Lower Limit of Normal (LLN) and an FVC that is also below the LLN.
To definitively differentiate whether this patient has a true mixed obstructive-restrictive defect or simply severe obstruction with hyperinflation, which test parameter must be evaluated next?
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Correct answer: B
Spirometry alone cannot diagnose a restrictive defect; a low FVC in the presence of obstruction often represents air trapping and hyperinflation (a pseudo-restriction). To definitively diagnose restriction, Total Lung Capacity (TLC) must be measured. If TLC is ULN), the low FVC is due to hyperinflation.
- 2
A patient referred for unexplained dyspnea undergoes a Cardiopulmonary Exercise Test (CPET). The results show:
- VO2 max: 60% of predicted
- Heart Rate Reserve (HRR): 45 beats/min
- Breathing Reserve (BR): 8% (or 6 L/min)
- O2 Pulse: Normal
Based on these findings, what is the most likely cause of the patient's exercise limitation?
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Correct answer: B
In CPET, a ventilatory limitation is indicated when a patient exhausts their breathing reserve (BR < 15% or < 11 L/min) before exhausting their cardiovascular reserve. Here, the patient has a very low breathing reserve (8%), but plenty of heart rate reserve (45 bpm) and a normal O2 pulse (indicating normal stroke volume). Therefore, the lungs (ventilation) limited the exercise before the heart reached its maximum capacity.
flowchart TD A[Low VO2 Max] --> B{Breathing Reserve < 15%?} B -->|Yes| C[Ventilatory Limitation] B -->|No| D{Heart Rate Reserve < 15 bpm?} D -->|Yes| E[Cardiovascular Limitation] D -->|No| F[Deconditioning / Poor Effort] - 3
According to the ATS/ERS 2022 Interpretive Strategies, which of the following combinations of PFT findings definitively confirms a MIXED (obstructive and restrictive) ventilatory defect? (Select TWO)
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Correct answer: A, B
A mixed defect requires the presence of BOTH obstruction and restriction. Obstruction is defined by an FEV1/FVC ratio below the Lower Limit of Normal (LLN).
A true restrictive defect can only be definitively confirmed by a Total Lung Capacity (TLC) below the Lower Limit of Normal (LLN). A low FVC alone is insufficient because it can be caused by air trapping in severe obstruction.
- 4
When preparing for a methacholine challenge test using a dosimeter, the technologist must verify the aerosol delivery output. The ATS guidelines recommend that the dosimeter deliver a specific volume of aerosol per actuation. What is the standard target volume delivered per breath when calibrating a dosimeter for this test?
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Correct answer: A
According to ATS guidelines for bronchial provocation testing, when using the 5-breath dosimeter method, the dosimeter should be calibrated to deliver 90 mcL (0.09 mL) of aerosol per actuation (breath). This precise calibration ensures that the cumulative dose of methacholine delivered to the patient is accurate.
- 5
A technologist is tasked with calibrating the exercise equipment prior to performing a cardiopulmonary exercise test (CPET). Which TWO of the following parameters MUST be verified when calibrating a cycle ergometer? (Select TWO)
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Correct answer: B, D
Cycle ergometers require calibration and verification of the pedal cadence (Revolutions Per Minute, RPM) and the mechanical resistance (workload/torque) applied to the flywheel, often verified using known calibration weights. Belt speed is a calibration parameter for a treadmill, not a cycle ergometer.
Cycle ergometers require calibration and verification of the pedal cadence (Revolutions Per Minute, RPM) and the mechanical resistance (workload/torque) applied to the flywheel, often verified using known calibration weights. Belt speed is a calibration parameter for a treadmill, not a cycle ergometer.
- 6
During the measurement of Thoracic Gas Volume (TGV/VTG) using a body plethysmograph, the technologist instructs the patient to pant against a closed shutter. What is the recommended panting frequency to ensure accurate measurements without causing excessive artifact?
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Correct answer: B
According to ATS/ERS guidelines for body plethysmography, the recommended panting frequency against the closed shutter for measuring TGV is between 0.5 and 1.0 Hz (30 to 60 breaths per minute). Panting too slowly can cause thermal drift artifacts, while panting too fast (>1.5 Hz) can cause pressure inequalities between the alveoli and the mouth, leading to overestimation of TGV, especially in patients with severe airway obstruction.
