A 52-year-old woman who was diagnosed with pulmonary emphysema 7 years ago and who smokes two packs of cigarettes a day is brought to the emergency department.She complains of having the flu 2 weeks earlier and that her breathing has become more difficult since then.Her pulmonary function test reveals the following results:
$\begin{array}{llll}
& \text { Predicted } & \text { Actual } & \text { Percent of Predicted } \
\mathrm{FVC}_{} & 4.67 \mathrm{~L} & 4.00 \mathrm{~L} & 86 \% \
\mathrm{FEV}_{1} & 3.52 \mathrm{~L} & 1.23 \mathrm{~L} & 35 \% \
\mathrm{FEV}_{1} / \mathrm{FVC} & \text { More than } 75 \% & 31 \% & -
\end{array}$
(A value equal to or greater than 80% of the predicted value is considered normal.)
What condition do these pulmonary function results suggest?

Question

A 52-year-old woman who was diagnosed with pulmonary emphysema 7 years ago and who smokes two packs of cigarettes a day is brought to the emergency department.She complains of having the flu 2 weeks earlier and that her breathing has become more difficult since then.Her pulmonary function test reveals the following results:
$\begin{array}{llll} 
& \text { Predicted } & \text { Actual } & \text { Percent of Predicted } \
\mathrm{FVC}_{} & 4.67 \mathrm{~L} & 4.00 \mathrm{~L} & 86 \% \
\mathrm{FEV}_{1} & 3.52 \mathrm{~L} & 1.23 \mathrm{~L} & 35 \% \
\mathrm{FEV}_{1} / \mathrm{FVC} & \text { More than } 75 \% & 31 \% & -
\end{array}$
(A value equal to or greater than 80% of the predicted value is considered normal.)
What condition do these pulmonary function results suggest?

Quizplus · Accepted Answer

Diagnoses of obstructive and restrictive patterns are traditionally based on three main variables: FVC, FEV₁, and FEV₁/FVC. This woman's test shows that the FVC is normal (above 80% of predicted), but the FEV₁ and FEV₁/FVC are decreased. The normal FVC rules out restrictive disease. These findings are consistent with an obstructive impairment because they point to expiratory airflow limitation. A normal person is expected to exhale about 80% of the FVC in the first second. This woman's reduced flows are probably caused by loss of elastic support in the airways, producing premature bronchiolar collapse during forced expiration. As the obstructive disease becomes more severe, the FVC also may decrease because air trapping limits her ability to exhale as much air as a normal person.

A 52-Year-Old Woman Who Was Diagnosed with Pulmonary Emphysema 7