What type of patient might present with an abnormally high FEV1/FVC ratio?

An abnormally high FEV1/FVC ratio is typically indicative of restrictive lung disease. This ratio is calculated by comparing the amount of air a person can forcibly exhale in one second (FEV1) to the total amount of air they can forcibly exhale (FVC) in one breath.

In restrictive lung diseases, such as pulmonary fibrosis or chest wall abnormalities, the lungs are unable to fully expand, leading to a reduction in both FEV1 and FVC. However, the reduction in FVC is usually more significant than the reduction in FEV1, resulting in a preserved or even elevated ratio. This contrasts sharply with obstructive lung diseases, where both FEV1 decreases, but the FVC may remain the same or only slightly reduced, leading to a lower FEV1/FVC ratio.

Patients with normal lung function would demonstrate a normal FEV1/FVC ratio, and lung cancer may not present with a distinct pattern unless there are obstructive complications or significant lung volume loss. Thus, the relationship between lung capacity and airflow restriction helps clarify why an elevated FEV1/FVC ratio aligns with restrictive lung disease.