Screening pulse oximetry and/or arterial blood gas analysis are indicated for a patient with known COPD when pulmonary function tests reveal which condition?

The correct response emphasizes that screening pulse oximetry and/or arterial blood gas analysis are essential for a patient with chronic obstructive pulmonary disease (COPD) particularly when pulmonary function tests show that the forced expiratory volume in one second (FEV1) is less than 65% of the predicted value. This metric is crucial because it indicates a significant level of airway obstruction, which is a hallmark of advanced COPD.

When the FEV1 drops below this threshold, it suggests a more severe stage of the disease where the patient is increasingly likely to have compromised gas exchange, leading to hypoxemia. Hence, further evaluation through pulse oximetry or arterial blood gas analysis becomes important to assess the patient’s oxygenation status and guide management decisions, such as the need for supplemental oxygen or other interventions.

In contrast to this correct choice, while the other options may identify concerning lung function, they do not inherently stipulate the same urgency for screening. The FEV1/FVC ratio being less than 75% and FVC being less than 60% may reflect airflow limitation and reduction in lung capacity, respectively, but they are not as definitive indicators of the critical need for immediate evaluation of oxygenation as an FEV1 less than