Which condition would present with a normal FEV1/FVC ratio?

Which condition would present with a normal FEV1/FVC ratio?

• A. Chronic bronchitis
• B. Asthma
• C. Restrictive lung disease
• D. Emphysema

Answer: (C)

A normal FEV1/FVC ratio indicates that both the forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC) are reduced proportionately. This scenario is typically observed in restrictive lung diseases, where the lung volumes are reduced but the airflow is not obstructed. In restrictive lung diseases, such as pulmonary fibrosis or conditions leading to lung stiffness, the FEV1 may decrease, but the FVC decreases by a similar amount, maintaining a normal ratio between the two. Thus, while total lung capacity may be reduced, the way airflow is affected differs from obstructive diseases, where the FEV1 is more severely reduced compared to the FVC, leading to a decreased ratio. This characteristic differentiates restrictive lung diseases from obstructive conditions such as chronic bronchitis, asthma, and emphysema, where patients would typically exhibit a decreased FEV1/FVC ratio due to airflow limitation. In these obstructive conditions, FEV1 is disproportionately lower compared to FVC, thus altering the ratio.

A normal FEV1/FVC ratio indicates that both the forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC) are reduced proportionately. This scenario is typically observed in restrictive lung diseases, where the lung volumes are reduced but the airflow is not obstructed.

In restrictive lung diseases, such as pulmonary fibrosis or conditions leading to lung stiffness, the FEV1 may decrease, but the FVC decreases by a similar amount, maintaining a normal ratio between the two. Thus, while total lung capacity may be reduced, the way airflow is affected differs from obstructive diseases, where the FEV1 is more severely reduced compared to the FVC, leading to a decreased ratio.

This characteristic differentiates restrictive lung diseases from obstructive conditions such as chronic bronchitis, asthma, and emphysema, where patients would typically exhibit a decreased FEV1/FVC ratio due to airflow limitation. In these obstructive conditions, FEV1 is disproportionately lower compared to FVC, thus altering the ratio.