CRE Pulmonary Function Testing & Interpretation 1 — Questions and Answers
Question 1: What is the FEV1/FVC ratio threshold used by GOLD guidelines to diagnose airflow obstruction in adults?
- Greater than 0.90
- Greater than 0.80
- Less than 0.70 (Correct answer)
- Less than 0.60
Correct answer: Less than 0.70
A post-bronchodilator FEV1/FVC ratio below 0.70 confirms the presence of persistent airflow obstruction per GOLD guidelines.
Question 2: A patient's spirometry shows a reduced FEV1/FVC ratio with normal or elevated TLC. This pattern is most consistent with which type of lung disease?
- Restrictive lung disease
- Obstructive lung disease (Correct answer)
- Mixed obstructive-restrictive pattern
- Normal lung function
Correct answer: Obstructive lung disease
Obstructive lung disease is characterized by a reduced FEV1/FVC ratio; TLC is normal or elevated due to air trapping and hyperinflation.
Question 3: Which spirometry measurement represents the volume of air forcefully exhaled during the first second of a maximal forced expiratory maneuver?
- FVC
- FEV1 (Correct answer)
- FEF25-75%
- PEF
Correct answer: FEV1
FEV1 (Forced Expiratory Volume in 1 second) is the volume exhaled in the first second of a forced vital capacity maneuver and is the primary indicator of airflow obstruction.
Question 4: The diffusing capacity of the lung for carbon monoxide (DLCO) is reduced in which of the following conditions?
- Asthma
- Obesity hypoventilation syndrome
- Emphysema (Correct answer)
- Vocal cord dysfunction
Correct answer: Emphysema
Emphysema destroys alveolar walls and capillary beds, reducing the surface area available for gas exchange, which significantly lowers DLCO.
Question 5: In restrictive lung disease, what change is observed in Total Lung Capacity (TLC)?
- TLC is elevated above 120% predicted
- TLC is reduced below 80% predicted (Correct answer)
- TLC remains within normal limits
- TLC fluctuates based on effort
Correct answer: TLC is reduced below 80% predicted
Restrictive lung disease is defined by a reduced TLC (<80% predicted), reflecting decreased lung volumes caused by parenchymal, pleural, or neuromuscular disease.
Question 6: According to ATS/ERS guidelines, a significant bronchodilator response requires an increase in FEV1 or FVC of at least what percentage AND absolute volume?
- 5% and 100 mL
- 10% and 150 mL
- 12% and 200 mL (Correct answer)
- 15% and 300 mL
Correct answer: 12% and 200 mL
ATS/ERS guidelines define a significant bronchodilator response as ≥12% relative increase AND ≥200 mL absolute increase in FEV1 or FVC from baseline.
Question 7: An elevated residual volume to total lung capacity (RV/TLC) ratio is most indicative of which finding?
- Pulmonary fibrosis
- Air trapping due to obstructive disease (Correct answer)
- Respiratory muscle weakness
- Pulmonary hypertension
Correct answer: Air trapping due to obstructive disease
An elevated RV/TLC ratio indicates significant air trapping, which occurs when obstructive disease prevents complete exhalation and gas accumulates in the lungs.
CRE Pulmonary Function Testing & Interpretation 1
What is the FEV1/FVC ratio threshold used by GOLD guidelines to diagnose airflow obstruction in adults?