Fundamental Study on Intraoperative Quantification of Gastrointestinal Viability by Transmission Light Intensity Analysis

Abstract

Abstract. In gastrointestinal surgery, surgeon subjectively judges if the organ is healthy from the color. However it is difficult to discriminate a small difference of organ's color by visual inspection. In this paper, we focus on the tissue oxygen saturation (StO 2 ) that represents balance of oxygen demand and supply in tissue and try to estimate its value by transmitted light intensity analysis. We developed a system for measurement of transmitted light intensity using a compact spectrometer and a halogen light source and collected transmitted light intensity data from pig's small intestines. Absorbance of the tissue was then calculated from those data. On the basis of Beer-Lambert law, we estimated StO 2 from the calculated absorbance. Results of evaluation experiment to pig's small intestines suggested the possibility of quantitative evaluation of tissue viability by the proposed method.

Estimation of Blood Oxygen Saturation in the Circulation Circuit for Extracorporeal Membrane Oxygenation

“…If the path length l is constant, the absorbance can be expressed by linearly combining the substances' molar extinction coefficients. Therefore, SO 2 can be estimated by solving a simple linear regression problem [9]. However, in reality, the path length l is not constant due to light scattering, and it must be defined as the optical path length function of the wavelength.…”