In chronic heart failure (HF), the alveolar-capillary membrane undergoes a remodeling process that negatively affects gas exchange. In case of alveolar-capillary gas diffusion impairment, arterial desaturation (SaO2) is rarely observed in HF patients. At play are 3 factors: overall pulmonary diffusing capacity (assessed as lung diffusion for CO, DLCO), global O2 consumption (VO2) and alveolar (A) to arterial (a) pO2 gradient (AaDO2).
Morosin M, Vignati C, Novi A, Salvioni E, Veglia F, Alimento M, Merli G, Sciomer S, Sinagra G, Agostoni P. The alveolar to arterial oxygen partial pressure difference is associated with pulmonary diffusing capacity in heart failure patients. Respir Physiol Neurobiol 2016 Jun 30 [Epub ahead of print]