Question

if someone can exhale forcefully 70 to 90 of fvc in 1 second, which of the following is true?
multiple choice
fvc is below normal.
fev1% is normal.
fef25 - 75 is low.
fef25 - 75 is high.

Explanation:

Forced expiratory volume in 1 second (\(FEV_1\)) as a percentage of forced vital capacity (\(FVC\)) (\(FEV_1\%\)) is calculated as \(\frac{FEV_1}{FVC}\times100\). A normal \(FEV_1\%\) value is typically in the range of 70 - 85% (some sources may consider up to 90% as normal depending on age and other factors). This value is used to assess obstructive (lower \(FEV_1\%\)) or restrictive (normal or higher \(FEV_1\%\) with reduced \(FVC\)) lung disorders. \(FEF_{25 - 75}\) (forced expiratory flow between 25% and 75% of \(FVC\)) is related to mid - expiratory flow and is not directly indicated by the given \(FEV_1\%\) range. \(FVC\) (forced vital capacity) being below normal would be indicated by a reduced absolute \(FVC\) value, not just the \(FEV_1\%\) range.

Answer:

FEV₁% is normal.