A combination of reduced FEV1, reduced FEV1/FVC, and increased Residual Volume (RV) indicates what type of defect?

The combination of reduced Forced Expiratory Volume in one second (FEV1), a reduced FEV1/FVC ratio, and increased Residual Volume (RV) is characteristic of an obstructive defect in pulmonary function. In obstructive lung disease, such as asthma or chronic obstructive pulmonary disease (COPD), airflow limitation primarily affects the exhalation phase of breathing. This limitation is demonstrated by the reduced FEV1, which represents the amount of air exhaled in the first second of a forced expiration.

Additionally, the FEV1/FVC ratio is crucial for determining the type of lung disease. In obstructive defects, both FEV1 and FVC values may be reduced, but FEV1 decreases more significantly than FVC. This results in a reduced FEV1/FVC ratio, typically below the normal threshold of 0.7.

The increased Residual Volume indicates that there is air trapping in the lungs, a common occurrence in obstructive conditions where the airway resistance leads to difficulty in fully emptying the lungs. This combination of findings—reduced FEV1, decreased FEV1/FVC ratio, and increased RV—strongly suggests an obstructive pattern in pulmonary function.