Continuous estimation of blood concentration of substances using photo-technology

本课题的目的是利用光纤导管结合先进的光电技术对多种物质的血药浓度进行估计。1.光学仪器的研制本光学仪器是为Abbott光纤导管设计的，能够提供和接收八种波长的光。2.寻找血液内物质我们研究了几种静脉药物和天然物质作为本项目的候选者。1）光吸收剂我们研究了吲哚菁绿色（ICG）、靛蓝胭脂红、磺酸盐卡巴胆碱和葡萄糖作为光吸收剂。其中ICG法最适合于此测量。虽然葡萄糖不吸收任何波长的可见光，但它的吸收光谱与水在近红外线的吸收光谱略有不同。我们研究了核黄素和异丙酚作为荧光剂。荧光强度与核黄素的浓度相关。异丙酚在血浆中由于与蛋白质结合而不发射荧光。3.体外研究在试管中的血样中研究ICG浓度与荧光强度的关系。ICG浓度在3 μg/ml以下与荧光强度呈线性关系，且在不同血红蛋白浓度的三种血样中，ICG浓度与荧光强度的关系基本一致。4.体内研究新西兰白色兔。从右颈静脉插入5.5 Fr Abbott光纤导管。将导管头端置于上级腔静脉、右心房和下腔静脉三个位置，记录每个位置的830 nm信号输出。在最小噪音的位置注射5 mg ICG。静脉注射5 mg ICG提供了足够强度的830 nm荧光信号。

The purpose of this project was to estimate blood concentrations of various substances using fibre-optic catheter in combination with advanced photo-technology.1.Producing an optical instrumentThis optical instrument that is able to supply and receive eight kinds of wavelengths of light, was designed for the Abbott fibre-optic catheters. This multi wavelengths optical instrument enabled to measure light absorption and fluorescence of intra-blood substances.2.Searching intra-blood substancesWe investigated several intravenous agents and native substances in vitro as candidates of the subjects in this project.1)Light absorbentWe studied indocyanin green (ICG), indigo carmine, sulphonate carbachrom, and glucose as light absorbents. Among them ICG was the most suitable for this measurement. Although glucose did not absorb any wavelength of visible light, its absorption spectrum was slightly different from that of water in near infrared.2)FluorescentWe studied riboflavin and propofol as fluorescents. Intensity of the fluorescence correlated to the concentration of riboflavin. Propofol in plasma did not emit fluorescence because of protein binding.3.In vitro studyRelationship between ICG concentration and the fluorescence intensity was studied in blood samples in a tube. The relationship between ICG concentration and the fluorescence intensity was linear up to 3 μg/ml, and this relationship was almost same in the three blood samples of different haemoglobin concentrations.4.In vivo studyNew Zealand White rabbits were studied. A 5.5 Fr Abbott fibre-optic catheter was inserted from right jugular vein. The tip of catheter was placed at three positions ; superior vena cava, right atrium and inferior vena cava, and recorded 830 nm signal output at each position. At the position of the minimum noise 5 mg of ICG was injected. The 5 mg of ICG injected intravenously provided sufficient intensity of 830 nm fluorescence signal.