Figure 10.

The alveolar-arterial difference at rest and during exercise to near maximal at different barometric pressures. There is no systematic relationship between A-aDO₂ and barometric pressure. This is likely due to a combination of factors including individual subject variability and the relative contributions of diffusion limitation, ${\dot{V}}_{\text{A}}/\dot{Q}$ inequality and shunt to the A-aDO₂ within a subject at different elevations. See text for details. Data are, with permission, from references (15, 46, 300, 302, 327, 334).