An effective model of blood flow in capillary beds.
In this article we derive applicable expressions for the macroscopic compliance and resistance of microvascular networks. This work yields a lumped-parameter model to describe the hemodynamics of capillary beds. Our derivation takes into account the multiscale nature of capillary networks, the influence of blood volume and pressure on the effective resistance and compliance, as well as, the nonlinear interdependence between these two properties. As a result, we obtain a simple and useful model to study hypotensive and hypertensive phenomena. We include two implementations of our theory: (i) pulmonary hypertension where the flow resistance is predicted as a function of pulmonary vascular tone. We derive from first-principles the inverse proportional relation between resistance and compliance of the pulmonary tree, which explains why the RC factor remains nearly constant across a population with increasing severity of pulmonary hypertension. (ii) The critical closing pressure in pulmonary hypotension where the flow rate dramatically decreases due to the partial collapse of the capillary bed. In both cases, the results from our proposed model compare accurately with experimental data.
Department of Pediatrics - Cardiology, Baylor College of Medicine, Houston TX, USA; Department of Pediatric Medicine - Cardiology, Texas Children's Hospital, Houston TX, USA. Electronic address: sacosta@bcm.edu.
Sebastian
S
Acosta
Department of Pediatrics - Cardiology, Baylor College of Medicine, Houston TX, USA; Department of Pediatric Medicine - Cardiology, Texas Children's Hospital, Houston TX, USA. Electronic address: djpenny@texaschildrens.org.
Daniel J
DJ
Penny
Department of Pediatrics - Cardiology, Baylor College of Medicine, Houston TX, USA; Department of Pediatric Medicine - Cardiology, Texas Children's Hospital, Houston TX, USA. Electronic address: crusin@bcm.edu.
Craig G
CG
Rusin
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002196:Capillaries / Q000473:pathology / Q000503:physiopathology*; D003187:Compliance; D003198:Computer Simulation; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000473:pathology / Q000503:physiopathology*; D007022:Hypotension / Q000473:pathology / Q000503:physiopathology*; D008168:Lung / Q000098:blood supply*; D008833:Microcirculation; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D012039:Regional Blood Flow; D013269:Stochastic Processes; D014655:Vascular Resistance
Compliance; Computational hemodynamics; Critical closing pressure; Hypertension; Lumped-parameter models; Microcirculation; Nonlinear Windkessel; Perfusion; Resistance