Temperature dependence of near-infrared spectra of whole blood

Abstract

The temperature dependence (30to40°C) of near-infrared spectra (500to1100nm) of whole human blood, including red blood cells with intact physiological function, is investigated. Previous studies have focused on hemoglobin solutions, but the operation of red blood cells is critically dependent on intact cell membranes to perform normal oxygen transport and other physiological functions. Thus measurements of whole blood are more directly related to changes that occur in vivo. In addition to the response of hemoglobin to temperature in the spectra, a temperature response from water in the plasma is also detected. The temperature response of the water absorption at 960nm is approximately ten times smaller than the temperature response of the oxyhemoglobin component in the blood at 610nm. However, it is the most significant temperature effect between 800 and 1000nm. This work will aid the precision and understanding of full spectrum near-infrared measurements on blood. © 2008 Society of Photo-Optical Instrumentation Engineers.