Interpreting Poiseuille's law for collapsible blood vessels

A vessel segment was terminated with a section of artery subjected to near zero transmural pressure. The sinusoidal frequency response was determined by solving the resulting nonlinear differential equations. A bifurcation diagram shows that there are many different values of instantaneous resistance obtained. We suggest that the cause of this may be the observer's choice of steady state. A consistent definition for steady state in blood vessels could resolve this problem.