A patient with shortness of breath and a history of smoking undergoes pulmonary function testing. What finding indicates COPD?

The correct answer highlights "increased total lung capacity" as a finding indicative of Chronic Obstructive Pulmonary Disease (COPD). In COPD, particularly emphysema, there is destruction of lung parenchyma leading to significant air trapping due to narrowed airways. As a result, the total lung capacity can be increased due to the residual volume being elevated, reflecting chronic overinflation of the lungs.

To understand the context further: a decreased FEV1/FVC ratio is also a classic finding in COPD, as this indicates a reduced ability to expel air rapidly, characterizing obstructive lung diseases. Normal lung volumes would not be expected in COPD, since the disease typically causes changes in lung volumes and capacities due to the airflow limitation and hyperinflation. Reduced gas exchange efficiency might occur in various pulmonary conditions, but it is not specific to COPD and does not directly reflect the characteristic changes seen in this disease.