Nerve Blood Flow and Oxygen Delivery In Normal, Diabetic, and Ischemic Neuropathy

The chapter discusses that in experimental ischemic neuropathy caused by exsanguination, the reduction in blood flow velocity is the major factor reducing endoneurial oxygen delivery. The chapter also presents that in arterial hypoxemia caused by reduced oxygen content of inspired air, the effects of reduced arterial oxygen tension (arterial hypoxia) are supplemented by effects of reduced blood flow (venous hypoxia) caused by reduction in cardiac output due to cardiac muscle hypoxia. In experimental edematous neuropathy (e.g., galactose neuropathy), the increased intercapillary distance is a major factor in reducing the oxygen supply. The adverse effects of increased intercapillary distance are partially offset, however, by a reduced oxygen consumption rate per unit volume of tissue that results from the effects of edema, because much of the increase in nerve volume is due to accumulation of extracellular fluid that is not metabolically active. Mathematical models of the release of oxygen from hemoglobin and its diffusion from capillaries to surrounding tissue have been applied to skeletal muscle, cardiac muscle and brain.