The Study Of The Related Law Of Hemodynamics In Noninvasive Ultrasonic Measurement Of Intracranial Pressure And Human Circulatory System Pressure

Intracranial pressure(ICP)is an important indicator for monitoring patients and guiding treatments.Traditional way of measuring ICP by invasive methods via a brain ventriculostomy or lumbar puncture features with complications and contraindications.In this thesis,we propose a novel method for measuring ICP through revealing the relationship between the retinal venous pressure(RVP),intraocular pressure(IOP)and ICP.Both the Sheet-Single Balloon Experiment and the Two Balloons Squeezing Experiment have been carried out to study the impacts of silica gel’s hardness,balloon’s curvature radius,filler’s compressibility,silicon membrane’s extensibility.A linear relationship between the weight of mass and the IBP has been found within the Sheet-Single Balloon Experiment.Through curve fitting technique,we find that the initial pressure(IP)has no effect on the slope of the curve,while other factors,i.e.silica gel’s hardness,balloon’s curvature radius,filler’s compressibility and silicon membrane’s extensibility,have significant impacts on the curve slope,which we define as Relevant Elastic Properties(REPs).For Two Balloon Squeezing Experiment,we have observed the impacts of IP and REPs on resulting curve shapes.Through proper statistical analyses,we build up mathematic models for the measurements of IBP via monitoring the IP of external water balloons.The model experiments reveal the mechanism for noninvasive ICP design using the ICP,RVP,IOP and IBP relationships.As such,a new method for non-invasive quantitative measurement of ICP can be established after subsequent animal and clinical experiments.Based on the high correlations between the RVP,IOP and ICP,an equipment designed for noninvasive ICP measurement by sonography at the retinal vein is presented.The feasibility was verified through a series of in-vitro model experiments.Classical text books in physiology indicated that because of the energy loss,the farther the arterial from the heart,the lower the arterial blood pressure is.However,many previous studies showed that,in physiological conditions,arterial blood pressure increases gradually as the blood flows from the aorta to the periphery arteries.It is unclear whether the peripheral blood pressure is still higher than that of the central artery under pathological conditions.The purpose of this study was to find out the changes of the aorta and peripheral radial arteries’ blood pressure in patients with cardiovascular disease.The aorta and peripheral radial arteries’ blood pressure in 43 patients with coronary heart disease was measured by heart puncture and the mean value was calculated.The systolic pressure of radial artery was significantly higher than that of the same individual,and the difference was statistically significant.Under physiological and pathological conditions,the systolic pressure and pulse pressure in patients with coronary heart disease were significantly higher than that of the aorta in patients.We applied the Bernoulli equation to explain the mechanism of this phenomenon.In total,the work accomplished within this thesis has indicated that the use of basic physical principles and laws to analyze and understand complex life phenomena has had a profound impact on medical scientific research work and will certainly bring broad and deep insights into future medical research and applications.