Study of an algorithm based on model experiments and diffusion theory for a portable tissue oximeter

Abstract

A portable tissue oximeter that uses light-emitting diodes and two-wavelength near infrared spectroscopy has been developed. The tissue oximeter is compact enough to be portable and it is therefore expected to make better use of the advantages of NIRS-based oximetry and to expand the scope of applications of monitoring tissue oxygen. The algorithm for this instrument was deduced through systematic experiments by varying blood volume and scattering intensity in a tissuelike phantom. The experimental results were compared with theoretical results obtained from diffusion theory. Experimentally determined coefficients of the algorithm were in close agreement with the theoretically derived coefficients. From evaluation tests of the algorithm applied to in vitro and in vivo measurements, it was confirmed that a good linear response to the concentration of oxygenated and deoxygenated blood can be obtained by this algorithm within a range of about a 50% change in concentration from an initial state. ©