Which pulmonary measurement is typically not routinely tested in chronic bronchitis?

• A. FEV1
• B. FVC
• C. Peak flow rates
• D. DLCO

Answer: (D)

In the context of chronic bronchitis, the measurement that is typically not routinely tested is DLCO, or diffusing capacity of the lungs for carbon monoxide.

Chronic bronchitis is primarily characterized by airway obstruction due to inflammation and excessive mucus production. The most common pulmonary function tests performed for patients with this condition include FEV1 (Forced Expiratory Volume in 1 second) and FVC (Forced Vital Capacity). These measurements help to assess the extent of airflow limitation and can indicate the severity of the disease. Peak flow rates may also be assessed, particularly to monitor changes in airflow and guide therapy, though they are less commonly used than the formal spirometry assessments.

DLCO is more relevant for conditions affecting the lung parenchyma, such as interstitial lung diseases or emphysema, rather than obstructive airway diseases like chronic bronchitis. In chronic bronchitis, the primary issue is with the airways rather than the alveolar gas exchange capacity, which DLCO measures. Therefore, testing for DLCO is generally not prioritized in the evaluation of chronic bronchitis.