Modeling Oxygen Transport in Human Lung Based On a Geometry Obtained By L-System

To model gas transfer in the human lungs the geometry of all airways (including conducting airways and respiratory airways) should be obtained. For this purpose, the structure has been divided into four parts ; 1) central airways: from trachea to segmental bronchi 2) dichtomous structure: from segmental bronchi to terminal bronchioles 3) Respiratory bronchioles 4) subacini: from respiratory bronchioles to air sacs. Stochastic parametric Lindenmayer System (L-System) has been applied for each part to obtain an anatomically accurate model of the structure. To predict the level of intra acinar O2 heterogeneity, the proposed model uses equations inspired by biophysics whose solution results in the oxygen distribution which cannot be measured directly. To reduce the computational cost, a simplified geometry of human airways is proposed based on the obtained accurate geometry. This simplified structure contains several typical paths, representative of conducting airways, for each bronchopulmonary segment coupled to the corresponding anatomically accurate asymmetric acinus. The results show that the proposed model can accurately describe the O2 hetrogenity in the human lung.

Keywords:

respiratory system , lung , O2 exchange