Pathophysiological alterations in oxygen delivery to the tissues

This paper reviews co-factors that impact on oxygen delivery and uptake, in the attempt to unravel the mechanisms underlying the correlation between the decrease in oxygen delivery and oxygen consumption. In sequence, the following factors are analyzed that, besides a decrease in haemoglobin concentration, impair tissue metabolism: (1) lung diffusion and perfusion limitation in oxygen transport, (2) decrease in cardiac output, (3) impairment of peripheral microvascular perfusion and (4) reduced ability of cells to extract oxygen. The contribution of the various factors is modeled aiming to present a decisional flow chart for the functional evaluation of the efficiency of the oxygen transport system.