Related Experiment Video
Updated: Mar 18, 2026

Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise
Published on: February 20, 2017
The alveolar to arterial oxygen partial pressure difference is associated with pulmonary diffusing capacity in heart
Marco Morosin1, Carlo Vignati2, Angela Novi2
1Centro Cardiologico Monzino, IRCCS, Milan, Italy; Cardiovascular Dept. "Ospedali Riuniti" Trieste and Postgraduate School Cardiovascular Sciences, University of Trieste, Italy.
Abstract:
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). In 100 consecutive stable HF patients, DLCO, resting respiratory gases and arterial blood gases were measured to determine VO2, paO2, pAO2 and AaDO2. DLCO was poorly but significantly related to AaDO2. The correlation improved after correcting AaDO2 for VO2 (p<0.001, r=0.49). Both VO2 and AaDO2 were independently associated with DLCO (p<0.001). Patients with reduced DLCO showed no differences as regards paO2 and pAO2. AaDO2/VO2 showed a higher gradient in patients with lower DLCO. AaDO2 increase and VO2 reduction allow preventing low SaO2 in HF patients with reduced DLCO. Accordingly, we suggest considering AaDO2 and VO2 combined and reporting AaDO2/VO2.
More Related Videos
08:44Author Spotlight: Integrating Alveolar-Capillary Reserve Measurements in Exercise Adaptation and Therapeutic Strategies
Published on: February 2, 2024
08:12Invasive Hemodynamic Monitoring of Aortic and Pulmonary Artery Hemodynamics in a Large Animal Model of ARDS
Published on: November 26, 2018
Related Concept Videos
Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
Gas Exchange and Transport
Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
External and Internal Respiration
Acute Respiratory Failure-I
Definition: It is defined by specific criteria based on blood gas measurements. Hypoxemia happens when the partial pressure of oxygen (PaO2) falls below 60 mmHg. At the same time,...
Acute Respiratory Failure-IV