Which of the following pulmonary function tests results indicate restrictive pulmonary disease?

Restrictive pulmonary disease is characterized by a reduction in lung volume, meaning patients have a limited ability to expand their lungs fully during inspiration. A hallmark of this condition is decreased forced vital capacity (FVC), which measures the maximum amount of air a person can exhale forcefully after taking a deep breath. In restrictive diseases, both the FVC and total lung capacity (TLC) are diminished due to factors such as lung stiffening or reduced lung compliance.

While total lung capacity is also reduced in restrictive lung disease, the specific reference to forced vital capacity, especially in the context of pulmonary function tests, solidifies the diagnosis of restrictive pattern. Therefore, a decreased FVC is a direct indication of the restrictive process.

In contrast, a decreased FEV1/FVC ratio typically indicates obstructive lung disease rather than restrictive lung disease, where both FEV1 and FVC are lower, but FEV1 drops disproportionately more. An increased FEV1 suggests better lung function, which does not align with the restrictive pattern. Lastly, while decreased total lung capacity may relate to restrictive disease, it is the changes in FVC that serve as a more immediate indicator in pulmonary function testing.