Pulmonary Function Testing Flashcards

Spirometry is primarily used to detect and quantify:

Answer: Obstructive and restrictive ventilatory defects

Spirometry measures airflow and lung volumes, allowing classification of ventilatory defects as obstructive, restrictive, or mixed.

An FEV1/FVC ratio below 70% (or below the lower limit of normal) indicates:

Answer: Obstructive lung disease

A reduced FEV1/FVC ratio is the hallmark of obstructive lung disease, indicating impaired expiratory airflow relative to total lung capacity.

In restrictive lung disease, spirometry typically shows:

Answer: Proportionally reduced FEV1 and FVC with a normal or elevated FEV1/FVC ratio

Restriction reduces overall lung volumes including FVC, but because both FEV1 and FVC decrease proportionally, the FEV1/FVC ratio is preserved or elevated.

The DLCO (diffusing capacity for carbon monoxide) is reduced in which condition?

Answer: Emphysema

Emphysema destroys alveolar walls and pulmonary capillaries, reducing the surface area available for gas diffusion and lowering DLCO.

Body plethysmography is used to measure which lung volume that spirometry cannot directly assess?

Answer: Residual volume

Residual volume (RV) cannot be measured by spirometry because it remains in the lungs after maximal exhalation; body plethysmography or gas dilution techniques are required.

Post-bronchodilator testing showing ≥12% and ≥200 mL improvement in FEV1 indicates:

Answer: Significant bronchodilator reversibility (consistent with asthma)

A 12% and 200 mL improvement in FEV1 after bronchodilator is the ATS/ERS criterion for significant reversibility, supporting an asthma diagnosis.