What does spirometry reveal for patients with obstructive lung diseases?

The correct answer indicates that spirometry reveals a decreased FEV1/FVC ratio in patients with obstructive lung diseases, which is a key characteristic of these conditions. In obstructive lung diseases like asthma and chronic obstructive pulmonary disease (COPD), there is a restriction in the airflow that primarily affects the amount of air a person can exhale over time.

The forced expiratory volume in one second (FEV1) measures the volume of air that can be forcibly exhaled in one second, while the forced vital capacity (FVC) measures the total volume of air exhaled during a forced breath. In obstructive diseases, FEV1 is reduced more significantly than FVC, leading to a lower FEV1/FVC ratio. This reflects the difficulty patients experience in getting air out of their lungs, a hallmark of obstructive lung pathology.

Understanding this is crucial for diagnosis and monitoring the progression of lung diseases. A decreased FEV1/FVC ratio signifies impaired airflow and indicates that the patient may need interventions to improve lung function. This information is vital when assessing the severity of the obstruction and planning appropriate treatments.