The Study On New Method Of Noninvasive Venous Pressure Measurement Based On The Airflow And Laser Detection Technology

Esophageal varices (EV) is a common complication for cirrhotic patients, about half of the patients with cirrhosis have esophageal varices when they were diagnosed. The main symptoms of EV is bleeding, and the higher level of liver function in patients, the higher for its EV rupture hemorrhage mortality. Therefore, for patients with cirrhosis, how to detect the risk populations with EV bleeding, predict bleeding tendency and develop reasonable treatment plan is particularly important. Currently, there exists two categories technology for human esophageal varices pressure measurement, both were carried out endoscopic, venous pressure measurement and venous outside pressure measurement. venous pressure measurement is puncture manometry, which is the accepted standard manometry method, however, this method can not be repeated manometry, puncture easily lead to bleeding or bacterial infections and has other shortcomings. Venous outside pressure measurement technology is the current hotspot. Currently, it includes two categories:one is esophageal varices adherent manometry technology, another is a balloon manometry. However, these two types of non-invasive pressure measurement method are difficult to effectively reduce interference to improve the accuracy, because the body is affected by many environmental factors. Therefore, in order to better predict the EV bleeding, need to find a more secure, accurate and reproducible endoscopic method for measuring EV pressure.Purpose:In this study, using optics combined with automatic control technology, computer real-time image detection technology, research the noninvasive method of noncontact pressure manometry combined with flow and laser.Based on the new method of manometry, develope the appropriate non-invasive pressure measurement instrument prototypes, and use the instrument to blood vessels in vitro and animal experiments. Assess the feasibility, accuracy and practicality for the new method of manometryPrinciple:Using the controllable airflow with small diameter to press vein wall, control air pressure changes continuously from small to large, while monitor the deformation of blood vessel wall. This study suggests that for convex thin-walled veins, at the time of the initial deformation of the outer wall of blood vessels, gas flow and intravascular hydrostatic pressure is equal to or a linear relationship.Method.1. Self-develope and design an adjustable pump, design and adjust the pump structure and the circuit, in order to achieve the operating frequency of pressure pulse form pump output and the pressure strength become adjustable. Using the adjustable pump can produce a stable, controlled pulse stream.(The process of pressure continuous change carried back and forth constantly, can repeately complete the measurements to the measured object, in order to improve the measurement accuracy);2. Research the gas flow generating pump,and pressure decay caused of the friction form the air flow and duct wall. Test airflow stress in a plurality of positions such as the pipeline,the vascular wall. Then analyze the relevance and function between the air pressure for each position, research whether the flow path of the pressure distribution is stability and the methods to Calculate3. Constructe the laser emitting apparatus, using laser beam emitted from the device, generate optical signals which can be captured by non-invasive pressure measurement system in the blood vessel wall for measurement4. Self-develope image acquisition and analysis system program, Using the existing endoscopic systems, continuous collect the optical image signal on venous pressure measurement position. By optical image analysis program, quickly capture the the optical signal changes of blood vessels distortion due to pressure5. Build synchronization system, simultaneous measure the change of air pressure and the deformation of the vein wall, achieve instrument to capture the moment of the vascular deformation,while simultaneously record the current pressure value6. Study blood vessels in vitro experiments, using analog vascular device which pressure was adjustable,and using the new methods of non-invasive measurement, experate the measurement for the bionic blood vessels and saphenous vein in vitro with the noninvasive pressure measurement instrument, compare the measured data with simulated blood vessels meter, through comparative analysis, verify the principle of this study;7. Study blood vessels in vivo experiments of animal, by dissecting the rabbits, to do noninvasive manometry and puncture manometry simultaneously for its inferior vena cava, through comparative analysis, further clear the feasibility, accuracy and practicality of the new method of noninvasive manometry.Result.1. A ccording to theory concept of the new method of noninvasive measurement, developed a new noninvasive pressure measurement instrument prototype. The prototype instrument active control airflow changed continuously, using the airflow as a shiatsued flow probe to pressure vessels, meanwhile using the laser detection technology, synchronously detecte the processment of vascular deformation; When varicose veins are indentated by the active airflow at initial time, records air pressure, according to the air pressure data in that time to calculate the pressure inside the blood vessel.2. Though in vitro and in vivo experimental vascular vascular experiments, the results of this study indicate that the pressure value of pressure measuring instrument and the actual pressure value of vessels bionic have good correlation, the linear regression equation was:Y=1.001X+6.036; The pressure value of pressure measuring instruments and the actual pressure value of vitro saphenous vein have good correlation, the linear regression equation was:Y=1.001X+9.703; The pressure value of pressure measuring instrument and puncture load instrument have good correlation, the linear regression equation was:Y=1.001X+10.820.Conclusion:In this study, the new method of noninvasive pressure measurement based on the airflow and laser detection technology is feasible, repeatability, has high measurement accuracy and has a good value...