Question

13
a patient who has a low fev1% and a low fef25 - 75 in a spirometry test should be diagnosed with
multiple choice
restriction.
pneumonia.
obstruction.
nothing. these values are normal.

Explanation:

• FEV₁% (Forced Expiratory Volume in 1 second as a percentage of FVC): In obstructive lung diseases (e.g., chronic obstructive pulmonary disease - COPD, asthma), there is airway narrowing. This makes it difficult for air to flow out of the lungs. As a result, the amount of air exhaled in the first second (\(FEV_1\)) is reduced relative to the total amount of air that can be exhaled (\(FVC\)), so \(FEV_1\%\) (\(FEV_1/FVC\times100\)) is low.
• FEF₂₅ - 7₅ (Forced Expiratory Flow between 25 - 75% of FVC): This measure reflects the flow rate during the middle portion of the forced expiration. In obstructive diseases, due to airway obstruction (e.g., from mucus, smooth - muscle constriction, or loss of elastic recoil in the lungs), the flow rate is reduced.
• Restriction: In restrictive lung diseases (e.g., pulmonary fibrosis), \(FVC\) is reduced, but \(FEV_1\%\) is often normal or high (because the air that can be exhaled is exhaled quickly).
• Pneumonia: Pneumonia may cause some changes in lung function, but the primary defects are related to gas exchange (e.g., V/Q mismatch) rather than the typical obstructive - pattern changes in \(FEV_1\%\) and \(FEF_{25 - 75}\).
• Normal values: Low \(FEV_1\%\) and \(FEF_{25 - 75}\) are not normal. These are indicators of abnormal lung function.

Answer:

obstruction.