Research And Development Of The Bilateral Encephaloblood-fluidity Signal And Monitor

Cerebrovascular disease was a kind of commonly and frequently encoutered disease which had endangered human life and health. And Cerebrovascular disease was the principal disease which caused wrinkly to be dead and disable, it was still of high sickness rate, disability rate, death rate and recurernce rate. Cerebrum was an important part of human organa, so there must be enough blood supply. Blood flux was the index of supplying blood to cerebrum, the supply of oxygen and energy would diminish in case shortage of supplying blood to cerebrum, then the function of cerebrum would vary, and Moreover, if a part of cerebrum blood flux was interrupted completely in a moment, partial brain tissue would necrotize, also namely brain infarct. Long-term cerebral anoxia or interruption of the blood supply of brain may cause serious consequences even lead to death. Therefore, it was necessary and significant to develop a technique to monitor the ischemic cerebrovascular disease and the blood flow of hemorrhagic cerebrovascular disease, which was favourable for developing research and guiding treatment, also assessing curative effect and giving an indication for preventing cerebrovascular disease.Firstly, this project studied the principle of non-invasive monitoring to the cerebral blood flow by impedance measuring technique and impedance plethsmography. And a constant exciting source of sinusoidal current was introduced based on plethsmography and the feature of blood flow signal. As a result, a dual admittance blood flow monitoring system was designed and implemented. In the hardware, silver chloride electrodes was adopted. The constant current exciting source was composed of direct digital synthesis sinusoidal (DDS) wave generator and operational amplifier. The resulting impedance signals were demodulated by detection and low-pass filtering circuit with amplifying, and acquired by 12 bits parallel ADC to computer after amplified and filtered with operational amplifier. In the process of dealing with blood flow signal, a method of removal baseline wander of encephaloblood-fluidity signal based on the method of spline interpolation was introduced, and measures for all kinds of disturb in blood flow signal was implemented. The base of dealing with blood flow was built by barrage jamming, which also obtained well effect. In the software system, acquisition of signals was controlled, the wave of blood flow was displayed, and the periodicity, amplitude, dimension of blood flow parameters was acquired by...