Final answer:
An FEV1:FVC ratio <0.70 post SABA use would be consistent with a diagnosis of chronic obstructive pulmonary disease (COPD) in a heavy-smoking 66-year-old man. This ratio indicates persistent airflow limitation, a key feature of COPD.
Step-by-step explanation:
The question pertains to the identification of a clinical sign consistent with the diagnosis of chronic obstructive pulmonary disease (COPD) in a 66-year-old man who has been a heavy smoker. An additional finding that would be consistent with a diagnosis of COPD in this scenario is c) an FEV1:FVC ratio <0.70 post SABA use. COPD is characterized by reduced airflow due to airway obstruction. In diagnosing COPD, spirometry testing is essential; a post-bronchodilator FEV1:FVC ratio (forced expiratory volume in one second to forced vital capacity) of less than 0.70 confirms the presence of persistent airflow limitation, which is a hallmark of COPD.
In contrast, an increased chest AP (anteroposterior) diameter may indicate hyperinflation associated with emphysema, one of the lung conditions encompassed by COPD. However, this alone does not confirm the diagnosis. Pleuritic chest pain would not typically be associated with COPD and an FEV1 improving by 50% with the use of a SAMA (short-acting muscarinic antagonist) might indicate a reversible component of airflow obstruction more characteristic of asthma rather than COPD.