Clinical system model for monitoring the physiological status of jaundice by extracting bilirubin components from skin diffuse reflectance spectra

Abstract

Neonatal jaundice is a medical condition which occurs in newborns as a result of imbalance between the production and elimination of bilirubin. The excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. As the bilirubin levels rise in the blood stream, there is a continuous exchange between the extra vascular bilirubin and bilirubin in the blood stream and exposure to phototherapy also alters the process. Diffuse reflectance spectra from human skin contains physiological and structural information of human skin and nearby tissue. Blanching, a phenomenon in which a slight capillary closure pressure is applied to force the blood under the applied area. A diffuse reflectance spectrum has to be captured before and after blanching to isolate the intravascular and extra vascular bilirubin.A new mathematical model is proposed with extra vascular bilirubin concentration taken into consideration along with other optical parameters in defining the diffuse reflectance spectrum of human skin. Nonlinear Optimization and Genetic Algorithms have been adopted to extract the optical properties (bilirubin concentration) from reflectance spectrum of skin. Bilirubin components were extracted from simulated diffuse reflectance spectrum within an average error of 10%