Mathematical modeling of hydrogen clearance blood flow measurements in peripheral nerve

The hydrogen clearance technique of blood flow measurement often yields biexponential washout curves. In peripheral nerve, arteriovenous shunt vessels may clear hydrogen gas, causing the fast component of a biexponential curve. We simulated the washout of hydrogen from nerve tissue in the vicinity of a large shunt vessel by modeling the diffusion of hydrogen through tissue to the vessel and its removal by a network of capillaries. We then determined the fast and slow clearance rates and the relative weights or contributions of the fast and slow components and found that they are affected by all of the model parameters.