Development Of Hepatic Functional Reserve Analyzer Based On Pulse Dye-densitometry

Liver disease is one of the major infectious diseases that threats human life andhealth. Chronic liver disease with its progression,if it can not be controlled by takingtimely and effective measurment, will result in liver cell damage, affect liver function,and even be made into fibrosis, cancer. When patients suffer from cirrhosis of theliver, hepatolithiasis, liver, huge hepatic hemangioma or other diseases whichimpaires hepatic functional reserve, liver resection、transplant、 or use of high sideeffect drugs may lead liver failure and even to death. Therefore, before taking thesemeasures, an accurate assessment of liver function is necessary. Liver functionalreserve pre-estimation can effectively increases the success rate and reduces theoperative mortality.Hepatic functional reserve is the sum of all liver cells function, is an importantindicator to human liver cell’s activity, health, and basic functionality,is a directreflection of the potential function of liver.Indocyanine green excretion experiment isstill widely used in the clinical as an evaluation of liver function. But traditionalartificial blood calibration method brings both doctors and patients difficulties due toits operational complexity and inefficiency, so the method is particularly necessary tobe improved. Liver functional reserve analyzer based on pulse dye-densitometryprovides a simple, less invasive, continuous and accurate methods. DDG3300K,products of Nihon Kohden,which is under the principle, has been widely used in theworld.The subject did some research work from the following two aspect, and madesome progress:1. Do some research about pulse dye-densitometry method and use it to measureindocyanine green concentration in blood by the mathematical physics model andcorrection method which is the basis for further discussion and analysis of therelevant parameters of liver function.2. Developed the instrument prototype of liver functional reserve analyzer based onpulse dye-densitometry.Do some research about weak pulse signal acquisition, conditioning, modulating and some other electronic circuit.The mathematical modelof the principle has been written into computer code.The instruments can be furthercalibrated, increase accuracy,and extensions as well as develop practical commercialpotential.Summary of this paper is showed as follow:The first chapter introduces the research content and background knowledge ofliver function evaluation in diagnosis and treatment, especially surgical riskassessment. Summarize current research on liver function assessment methods andequipment.The second chapter describes a mathematical model of the pulse dye-densitometryand the compensation method. The principle is the methodological basis ofdeveloping the instrument, and is the theoretical basis of the instrument upgrade.The third chapter describes the design of the instrument’s hardware, includingoptical sensors, all levels of the analoge conditioning circuit and data acquisitionsystem.And give a systematic analysis of the various stages of signal in both timeand frequency domains.The fourth chapter describes the curve of indocyanine green’ concentration,computing of the important parameters of the15-minute retention rate, and plasmadisappearance rate,and its software implementation.The fifth chapter is about data analysis. Compares the datas of our instrumentmeasured with DDG-3300k measured to find the correlation. We find it issignificantly related, and the correlation coefficient is over0.96.The sixth chapter sums up the whole paper,and gives the next step ofimprovements.