Free RPFT sample questions

Correct answer: Significant, based on both FEV1 and FVC changes.

According to ATS/ERS criteria, a significant bronchodilator response is an increase of >12% AND >200 mL in either FEV1 or FVC from baseline. FEV1 change: (1.25 L - 1.0 L) = 0.25 L (or 250 mL), which is >200 mL. The percent change is (0.25 L / 1.0 L) * 100 = 25%, which is >12%. So, the FEV1 response is significant. FVC change: (2.8 L - 2.5 L) = 0.30 L (or 300 mL), which is >200 mL. The percent change is (0.30 L / 2.5 L) * 100 = 12%. So, the FVC change is also significant. Since both parameters show a significant change, the overall response is significant.

Correct answer: Linearity; Yes, the deviation at each point is within 3% of the reading.

This procedure evaluates the linearity of the spirometer, which is its ability to provide accurate measurements across its volume range. The ATS/ERS standard for linearity requires that the measured volume at each step be within 3% of the reading or 50 mL, whichever is greater. Step 1: 1.01 L is a 1% error from 1.0 L. (Meets criteria) Step 2: 2.03 L is a 1.5% error from 2.0 L. (Meets criteria) Step 3: 3.05 L is a 1.67% error from 3.0 L. (Meets criteria) Since all points are well within the 3% tolerance, the spirometer meets the linearity standard.

Correct answers: Immediately stop the test.; Record the time and distance at which the test was stopped.

The ATS guidelines for the 6MWT provide specific criteria for stopping the test. Significant oxygen desaturation (typically to <88%) and patient-reported intolerable dyspnea are absolute indications to terminate the test for safety. The technologist must stop the test immediately and have the patient rest. It is also critical to document the reason for stopping, the time elapsed, the distance covered, and the lowest SpO2 reading.

Correct answer: A significant leak in the breathing circuit.

The primary cause of a falsely high FRC and TLC in a helium dilution test is a leak. A leak allows helium to escape the closed circuit, leading to a lower final helium concentration than expected. The calculation assumes this lower concentration is due to dilution in a larger lung volume, thus falsely elevating the calculated FRC and subsequently the TLC. This result is internally inconsistent with the restrictive pattern seen on spirometry, pointing to a technical error rather than a physiological reality.

Correct answer: False

False. The 2017 ATS/ERS standard for single-breath DLCO testing states that for a maneuver to be acceptable, the inspired volume (IVC) must be at least 85% of the best previously measured FVC or VC. An IVC of only 75% of the best FVC indicates a submaximal inspiration, which would lead to an underestimation of the DLCO. Therefore, this maneuver is unacceptable and should be repeated.

Correct answer: Correction for inspired oxygen pressure (altitude).

While both hemoglobin and altitude affect DLCO, the effect of altitude is more pronounced and is a required correction. At 5,000 feet, the partial pressure of inspired oxygen (PiO2) is significantly lower than at sea level. This lower PiO2 creates a smaller back-pressure for CO, leading to a falsely elevated measured DLCO. A correction must be applied to normalize the value to sea-level conditions. The patient's hemoglobin is normal for a male, so a correction would have minimal impact, making the altitude correction the most critical adjustment.

Correct answer: Ventilatory limitation

A key indicator of ventilatory limitation during exercise is a low breathing reserve (BR). The BR is the difference between the maximum voluntary ventilation (MVV) and the peak minute ventilation (VE) during exercise. A BR of less than 15% (or <11 L) indicates that the patient has nearly exhausted their capacity to breathe and is therefore limited by their pulmonary system. In this case, a BR of 5% is a strong indicator of a primary ventilatory limitation. The high heart rate reserve (40%) suggests the cardiovascular system was not the primary limiting factor.

Correct answer: Recalibrate the analyzer and rerun the control.

The standard first step in troubleshooting a failed QC on a blood gas analyzer is to perform a recalibration and then rerun the same level of control. This simple action often resolves issues related to electronic drift or minor fluctuations. If the control fails again after recalibration, more invasive steps, such as checking the electrode membrane or replacing reagents, would be warranted. Immediately replacing components is inefficient and not cost-effective.

Correct answer: A combined obstructive and restrictive defect with severe diffusion impairment.

This patient presents with a classic mixed pattern. The FEV1/FVC ratio is low (50%), indicating airflow obstruction (from COPD/smoking). The Total Lung Capacity (TLC) is also significantly reduced (65% pred), confirming a coexisting restrictive process (from silicosis or RA-ILD). The severely reduced DLCO (40% pred) is consistent with both emphysema (obstructive) and interstitial lung disease (restrictive), supporting the combined diagnosis. The patient's complex history provides context for this mixed physiological picture.

Correct answer: 1.5%

The standard endpoint for a nitrogen washout test is when the nitrogen concentration falls to a low and stable level, indicating that the nitrogen in the functional residual capacity (FRC) has been adequately washed out. The ATS/ERS guideline for this endpoint is a nitrogen concentration of less than 1.5% for at least three consecutive breaths.