Multiscale analysis of simultaneous uptake of two reactive gases in the human lungs and its application to methemoglobin anemia

摘要

We present a novel multiscale modeling and simulation methodology for quantifying the simultaneous uptake of two reactive gases in the human lungs, and apply it to predict pulmonary hypoxemia in patients suffering from methemoglobin anemia (resulting from excess inhaled nitric oxide (NO)). We start with the convection-diffusion-reaction equations at each scale of the lung and apply a spatial averaging technique (based on Liapunov-Schmidt method of the classical bifurcation theory) to obtain low-dimensional multiscale models. Our simulations for methemoglobin anemia show that while breathing in room air, the O_2 saturation in the patient's hemoglobin falls to below 94% at 50ppm NO, and above 203 ppm, NO causes severe hypoxemia by reducing the O_2 saturation to below its critical value of 88%. We predict that patients respond to O_2 therapy up to inhaled NO levels of 271 ppm, above which they are candidates for methylene blue therapy.