Fig. 3.
Proposed nonlinear arterial tube-load model technique for estimation of PTT as a function of BP from proximal and distal BP waveforms. The nonlinear model accounts for BP-dependent arterial compliance and peripheral wave reflection (top panel). The parameters [α (degree of BP-dependence), G, fc] are estimated by finding the finite-difference relationship (see the Appendix) that optimally fits Pp (t) to Pd (t) (middle panel). PTT as a function of BP [Td (P)] is then given via the α estimate and D2LC0 (bottom panel). Note that D2LC0 is specified by the α estimate, the estimate via the linear arterial tube-load model technique, and MP (middle panel).