Diffusion and perfusion limitation in alveolar O2 exchange: shape of the blood O2 equilibrium curve.

摘要: Abstract The limitations imposed by diffusion (Ldiff) and perfusion (Lperf) on alveolar gas exchange can be estimated using a simple model of alveolar-capillary transfer (Piiper Scheid (1981) Respir. Physiol. 46: 193–208). These indicate the fractional increase that would occur raising pulmonary conductances for or to functionally infinite values. (simple) assumes linear relations between concentration partial pressure gases studied. We have investigated in this study effects assumption estimating Ldiff Lperf O2 whose blood equilibrium curve is particularly non-linear normoxia. calculations suggest only slightly overestimated binding. For Ldiff, there significant overestimation normoxia, but hypoxia yields sufficiently accurate estimates. Calculations data man summit Mt. Everest uptake deep at rest mainly limited lesser degree (Lperf > Ldiff). sustained exercise climbing, other hand, limitation more prominent than (Ldiff Lperf). Large values are normoxic across skin gill-less lung-less salamander, here, alinearity pronounced. It concluded simplified transfer, with curve, very useful estimate from experimental data.