Oxygen-Carbon Dioxide Transport to and From Blood Flowing Under Pulsatile Conditions in Semipermeable Tubes

摘要

This paper presents a mathematical model that describes the phenomena of oxygenation and carbon dioxide removal in blood flowing in semipermeable tubes under pulsatile flow conditions. The model considers the blood as a homogeneous fluid with gas sinks uniformly and continuously distributed in it. The membrane resistance to the gas transport and the possibility of gas transport augmentation in the blood due to the rotation of the erythrocytes in the velocity field are also included in the model. The partial differential equations for the gas transport were solved numerically using a digital computer. Simultaneous solutions for oxygen and carbon dioxide were obtained, and the pH was computed for any point in the tube. Comparison of experimental data obtained by the author with the curve predicted by the model shows excellent agreement. The numerical solution yields the bulk average values of pH, carbon dioxide partial pressure, and oxygen saturation as a function of tube length. The effect of frequency, wave amplitude, wave shape, flow, and tube dimensions was investigated using the model. It was found that all these parameters enhance the gas transport, and that asymmetric flow waves are more effective than are symmetric waves. In general, gas transport to blood under pulsatile flow is considerably more efficient than gas transport to blood under steady flow. (Author)