Characterization of forced expiratory volume in 1st second, diffusing capacity for carbon monoxide and partial pressure of oxygen in arterial blood in patients with COPD
Authors: Patrícia Pereira, Mafalda de Sousa, Raquel Barros
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The Chronic Obstructive Pulmonary Disease (COPD) is characterized by a persistent bronchial obstruction, partially reversible and progressive, associated with an abnormal inflammatory response of the lungs to inhaled noxious particles or gases.
According to GOLD, spirometry is the primary test conducted in the context of COPD. This pulmonary function test can determine the relationship between forced expiratory volume in the 1st second and forced vital capacity (FEV1/FVC) after bronchodilation, which establishes the presence of airway obstruction. The spirometry can also characterize the degree of severity of bronchial obstruction in these patients by analyzing FEV1 (%). Besides the spirometric parameters other functional respiratory variables like diffusion capacity for carbon monoxide (DLco) and partial pressure of oxygen in arterial blood (PaO2) should be evaluated.
The aim of this review article is to characterize, by analyzing the literature, FEV1, DLco and PaO2 in patients with COPD.
Despite FEV1 (%) is considered the gold standard for characterizing the severity of bronchial obstruction, this parameter has limitations, because its decrease does not always reflect the presence of COPD.
According to the literature, DLco is generally decreased in patients with COPD, reflecting the presence of emphysema, and PaO2 is also diminished. Both values of DLco and PaO2 decrease with the increasing of severity of the obstruction.
Studies have shown that in patients with COPD there is a relationship between FEV1 and DLco with PaO2.