Spirometry Flashcards

Which spirometry value is the BEST single indicator of the severity of airflow obstruction in COPD?

Answer: FEV1 % predicted

FEV1 % predicted is the standard measure used by GOLD guidelines to grade severity of airflow obstruction in COPD.

The FEF25-75% (forced expiratory flow from 25% to 75% of FVC) is most sensitive for detecting dysfunction in which airways?

Answer: Small peripheral airways

FEF25-75% reflects flow through small peripheral airways and may be reduced early in obstructive disease before FEV1 declines.

A patient performs spirometry and the two largest FVC values differ by more than 150 mL. What does this indicate?

Answer: The test is acceptable but not reproducible

Per ATS/ERS guidelines, if the two largest acceptable FVC values differ by >150 mL, reproducibility criteria are not met, though individual maneuvers may still be acceptable.

Which condition would most likely produce a fixed upper airway obstruction pattern on a flow-volume loop?

Answer: Tracheal stenosis

Tracheal stenosis causes a fixed obstruction that flattens BOTH the inspiratory and expiratory limbs of the flow-volume loop equally.

Post-bronchodilator testing shows FEV1 increases by 240 mL and 13% from baseline. How should this be interpreted?

Answer: Significant bronchodilator response

ATS/ERS criteria define a significant bronchodilator response as an increase in FEV1 or FVC of ≥200 mL AND ≥12% from baseline.

During spirometry, a patient coughs during the forced exhalation. What is the impact on test acceptability?

Answer: The maneuver is acceptable only if cough occurred after 1 second

ATS/ERS guidelines state that coughing during the first second of exhalation renders the maneuver unacceptable, as it affects FEV1 measurement.

What is the primary purpose of volume calibration verification in spirometry?

Answer: To ensure the spirometer accurately measures volumes

Volume calibration verification using a 3-liter syringe confirms the spirometer accurately measures known volumes within ±3.5% error.