Pulmonary blood flow and tissue volume: model analysis of rebreathing estimation methods.
As the basis for comparing rebreathing methods of estimating pulmonary blood flow (Q) and tissue-capillary volume (Vtc), we use a dynamic mass-balance model for gas species having different physicochemical properties (e.g., He, CO, C2H2). The model accounts for the effects of ventilation and perfusion inhomogeneities, breathing pattern variation, lung and rebreathing-bag volumes, and recirculation. Also, we examine the variability of the estimates caused by random error. In addition to analyzing two well-known methods, we show how an appropriate synthesis of these methods can lead to improved estimates.
D006801:Humans; D008176:Lung Volume Measurements; D008954:Models, Biological; D011652:Pulmonary Circulation; D012129:Respiratory Function Tests / Q000379:methods*; D014692:Ventilation-Perfusion Ratio