Pulmonary haemodynamics

Abstract

Pulmonary hemodynamics is studied in terms of the quasi one-dimensional unsteady nonlinear fluid flow equations which are applied to the approximately 40 generations of branched arterial, capillary and venous distensible vessel segments making up the four lobes of the complete lung. An idealised pressure-area ‘tube law’ is introduced which provides for varying degrees of vessel collapse. The model predictions agree well with experimental measurements of flow transmission as a function of pulsatile frequency. Pulmonary response is represented schematically in terms of an influence diagram. Pressure pulses are shown to increase in amplitude in the early arterial segments, with the greatest drop occurring across the capillary bed.