Pulmonary diffusing capacity, also known as lung diffusion capacity or DLCO (diffusing capacity of the lungs for carbon monoxide), is a measurement used to assess the ability of the lungs to transfer gases from the alveoli into the bloodstream. It provides valuable information about the efficiency of gas exchange in the lungs.
Pulmonary diffusing capacity is typically measured by having the individual breathe in a small amount of a non-toxic gas, such as carbon monoxide (CO), for a specified period of time. The gas is then exhaled, and the concentration of the gas in the exhaled air is measured. By comparing the concentration of the gas inhaled to the concentration exhaled, the diffusing capacity can be calculated.
This test evaluates the functioning of the alveolar-capillary membrane, which is responsible for the exchange of oxygen and carbon dioxide. Various factors can affect pulmonary diffusing capacity, including the health of the alveoli, blood flow within the capillaries, and the affinity of hemoglobin for gases.
A reduced pulmonary diffusing capacity can indicate the presence of lung diseases such as chronic obstructive pulmonary disease (COPD), interstitial lung disease, pulmonary embolism, or pulmonary hypertension. It can also be affected by other conditions like anemia or heart failure. Conversely, an increased diffusing capacity may suggest conditions like polycythemia or pulmonary hemorrhage.
Overall, the measurement of pulmonary diffusing capacity helps healthcare professionals assess lung function, diagnose respiratory diseases, monitor disease progression and response to treatment, and determine an individual's ability to participate in activities of daily living.
