Which of the following conditions define an obstructive impairment?

An obstructive impairment is characterized by a reduction in airflow, which is primarily assessed through the forced expiratory volume in one second (FEV1) and the FEV1 to forced vital capacity (FVC) ratio. In obstructive diseases such as asthma or chronic obstructive pulmonary disease (COPD), patients typically exhibit a low FEV1 due to the limitation in airflow during expiration. The FEV1/FVC ratio is also reduced because while both volumes can be decreased, the FEV1 drops more significantly compared to FVC.

In this context, a low FEV1 paired with a low FEV1/FVC ratio indicates obstructive impairment. This pattern is consistent with the pathophysiology of obstructive lung diseases where the main issue is the inability to exhale air rapidly, leading to trapped air in the lungs and diminished expiratory flow rates.

The other options do not represent obstructive impairments. High FEV1 values would indicate that airflow is not significantly compromised. A normal FEV1 with low FVC could suggest restrictive lung disease rather than obstruction. A decreased vital capacity may occur in various conditions, including both restrictive and obstructive diseases, but does not specifically point to obstructive impairment without considering the