Pulse propagation in the pulmonary and systemic arteries

The one-dimensional model of Olufsen (2000) [*] for blood flow in the systemic arteries has been extended and built upon in a number of ways. Firstly, it has been applied to hypotheses of diseases of the systemic circulation, and that of the microcirculation. With a view to better understanding the microcirculation (the smallest vessels of the systemic circulation) and its diseases, the model has been extended to provide predictions of the propagating pressure pulse and flow rate in small arteries. Secondly, Olufsen’s model has been used as a base upon which to build a model of the pulmonary circulation, incorporating both the pulmonary arterial and venous circulations, with detailed simulations of pressure and flow predicted in the large pulmonary arteries and large pulmonary veins. To this end, a new model has been eveloped to describe a connected network of small arteries and small veins, replacing the small arterial model used as an outflow condition in the original model. A new outflow condition to describe the return of blood from the pulmonary venous system to the left atrium of the heart has also been implemented. Finally, this new pulmonary model has been applied to various hypotheses as to the causes of diseases and disorders of the pulmonary circulation, providing predictions of pressure and flow in the large pulmonary arteries and veins in both normal and abnormal circumstances, and showing agreement with clinical observations. [*] M.S. Olufsen at al. Numerical simulation and experimental validation of blood flow in arteries with structured-tree outflow conditions. Ann Biomed Eng, 28:1281–1299, 2000