Question:easy
In chronic obstructive pulmonary disease (COPD), which of the following spirometry findings is true?
In chronic obstructive pulmonary disease (COPD), which of the following spirometry findings is true?
Show Hint
The defining spirometry criterion for COPD is a post-bronchodilator FEV1/FVC below 0.7.
Updated On: Jun 24, 2026
- FEV1/FVC less than 0.7
- Normal FEV1/FVC ratio
- Reduced residual volume
- Increased FEV1
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Think of COPD as a problem of getting air out. The lung empties slowly, so the volume blown out in the first second is disproportionately small.
Step 2: Spirometry expresses this as the FEV1 divided by the total FVC. When that fraction drops below 0.7 after a bronchodilator, obstruction is confirmed. This single cutoff is the accepted definition of COPD.
Step 3: The other choices contradict the disease physiology. Air trapping raises residual volume rather than lowering it, FEV1 declines rather than rises, and a preserved ratio would mean no obstruction at all.
Step 4: So among the listed findings, only the reduced ratio below 0.7 matches COPD.
\[\boxed{\text{FEV1/FVC} < 0.7}\]
Step 2: Spirometry expresses this as the FEV1 divided by the total FVC. When that fraction drops below 0.7 after a bronchodilator, obstruction is confirmed. This single cutoff is the accepted definition of COPD.
Step 3: The other choices contradict the disease physiology. Air trapping raises residual volume rather than lowering it, FEV1 declines rather than rises, and a preserved ratio would mean no obstruction at all.
Step 4: So among the listed findings, only the reduced ratio below 0.7 matches COPD.
\[\boxed{\text{FEV1/FVC} < 0.7}\]
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