| The diagnosis of cardiovascular disease can be achieved through the measurement ofphysiological parameters, such as ECG (electrocardiogram), blood Pressure, oxygen saturationbody temperature and heart rate. Because the features of intermittent attacks, reliable diagnosisresult of heart disease requires continuous dynamic monitoring data as a basis. Holter monitoringsystem is capable of recording ECG signals for more than24hours. With the help of computerprocessing software, ECG signals could be playback and analysis by doctors, in order toconfirming the health condition. Salt composition in ECG electrodes which are used by Holtermay penetrate into the skin and cause allergic dermatitis. A standard ECG dynamic monitoringrequires a long time, which causes the electrolyte gel in electrodes experience dehydration anddrying. As a result, the signal sensitivity and signal to noise ratio decreased by changes of contactresistance between the electrodes and skins. IN addition, Holter is lack of real-time ECG analysiscapabilities. It is hard for patients to alert medical staff in time when heart disease outbreak. In thefield of blood pressure measurement, measurement based on Korotkoff sound is widely used inclinical application, which needed blood pressure cuff. This method may cause patients feelingbad and tension, and can not realize continuous measurement because a signal measurement takesover1minutes to. In oxygen saturation measurement, the environmental disposal requirementmade invasive measurements could not be using widely. The noninvasive oximetry method basedon photoplethymography is lack of anti-interference ability. In clinical medicine, the monitoringof ECG, blood oxygen saturation, blood pressure, body temperature always requires separateequipments, which increased the total size of equipment and costs of measurement. In order tosolve the problems, with the help of comprehensive utilization of wireless communications, newmaterials technology, digital signal processing technology, small sensors signal condition circuitryand control processing united, an wearable clothing which integrated with these technologies wasrealized. Two kind of software based on handheld device and computer were developed, withwearable cloth, constitute the physiological parameters monitoring system which can realize thefunctions of ECG monitoring, blood pressure measurement with cuff, temperature measurement,and blood oxygen saturation measurement. This project is funded by the major projects named"Development of wearable non-invasive body parameters continuous monitoring instruments" ofthe science and technology department of JiLin Province. Main contents and results are asfollows:1. Designing and production of wearable clothing. Choosing the reasonable material to madecloth, design the structure of the cloth, planning layout area for wires, enhanced wearing comfort. Providing a platform for electrodes, measurement unit and pulse wave sensor.2. Realization of ECG measurement with fabric electrodes. Decreased the stimulating to skin, bydeveloping new ECG electrodes with conductive textile materials. Improving the signal tonoise ratio of ECG signal by lower the interference caused by contact resistance changebetween skin surface and electrodes, with the method of adjusting outer coating material anddimension of electrodes. Testing the reliability of the measurement circuit with ECG detector.Designing wear clothing structure, planning layout area for wires, in order to improving thewearing comfort. Improving the signal to noise ration by designed a signal conditioningcircuit for ECG signal which considered the characteristics of the fabric electrodes.3. Implementation of dual-wavelength pulse wave measurement function. Development of thefinger grip of the photoplethysmography sensor. Selecting the wavelength of light sourcebased on the absorption spectrum of hemoglobin. Making the light source drive circuit andthe signal conditioning circuit, both efforts provide a reliable signal source for themeasurement of oxygen value and blood pressure values. Researching and realizing a kind ofdistorted pulse wave recognition algorithm according to motion artifact interference factorswhich are easily introduced in dynamic pulse wave acquisition. A concept named pulse wavedistortion coefficient is proposed to judge whether the distorted pulse wave has medicalsignificance or not.4. Implementation of measurement unit. A pulse wave sensor drive circuit, a pulse wave signalconditioning circuit, a ECG signal conditioning circuit, a temperature measuring circuit, amicroprocessor module, a data storage module, a communication module and a power module,were produced and integrated in measurement unit which placed in wearable clothing.5. Research on physiological parameter calculation method. Blood pressure measurementmethods without cuff were carried out. The linear relationship between the pulse wave transittime and systolic blood pressure was verified by formula derivation and actual experiments.Proposed two fitting calculation method to calculate artery diastolic pressure based on bloodvessel cavity model and pulse wave coefficient. Accuracy of the algorithm for blood pressurecalculating were got by compared tests. Based on the characteristics of the light sourcewavelength of the pulse wave sensor and light absorption law, a kind of oxygen saturationfitting algorithm was developed. Another oxygen saturation calculation method which basedon adaptive filter to anti-interference in oxygen saturation calculation was applied too. A kindof abnormal ECG waveform recognition algorithm based on QRS complex group and RRinterval was studied and implemented on PDA platform.6. Realizing of physiological information monitoring software. Tow kind of physiologicalparameter monitoring software were implemented for PDA and computer. Realizing thefunction of ECG waveform display, pulse waveforms display, temperature display, abnormalECG recognition, oxygen saturation calculating, blood pressure calculating and wirelesstransmission of data. Two kind of filtering algorithm based on two platforms were realized inorder to improving the signal to noise ration and increasing the accuracy of physiologicalparameter calculate algorithm. A data transfer channel between handheld terminal andcomputer was funded with TCP/IP protocol.7. Accuracy of measurement results were verification by actual experiments. Accuracy of theECG diagnostic algorithm was verified by standard ECG database. Then actual ECG signalwhich extracted from the surface of volunteers' skin, which were used to verified the accuracy of the ECG detecting algorithm which was implemented on handheld terminals andcomputer. Got blood pressure measuring points of volunteers by movement method, analysisthe accuracy of cuffless blood pressure calculate method. Changing the oxygen saturation ofvolunteer's blood as a mean of control respiratory rate. Analysis the accuracy of measurementresults. The tests' results showed the instrument reached the designed goal.Innovative work in this paper is as follows.1. The measurements of ECG, blood pressure, oxygen satruration and temperature areintegerated into a wearable measuring device. The dynamic measurement ofphysiological signal are integrated in the wearable shirt and measuring unit. A method ofusing conductive fabric to making electrodes had been implemented in order to fix upthe shortcomings of traditional electrodes in ECG signal extracting, which reduce thestimulation of the electrodes on skin. Signal conditioning circuits and software filterswere designed to solve the problems in ordinary dynamic ECG monitoring. ECGmonitor module was divided into two parts, wearable shirt and measurement unit.Wearable shirt was designed to reduce the obstacles of the instrument on humanactivities and enhanced wearing comfort.2. Proposed concept of associate factor of pulse features (AFP). R-wave in ECG time serieswere used as feature points which divided pulse waveform into many pieces by heartbeatcycle. Characteristic value of each piece was extracted and into a specific formula. Then,a new parameter named AFP was granted. The medical significance of each piece couldbe determined by contrasting the AFP to pre-set threshold. Signals, which had nomedical significance, would be filtered by software in order to avoiding interference oncalculation results.3. Proposed two diastolic blood pressure calculation methods without needing for cuff,which were implemented on PDA and computer respectively. The relationship betweensystolic blood pressure and diastolic blood pressure was derived based on vascularcomponent elastic chamber model. Vascular compliance C and vascular resistance Rwere fit by pulse waveform coefficient. This method reduces the size of the equipmentand computation cost, which made it suitable for PDA platform. A new componentnamed L which reflects the blood inertia was introduced into vascular model. A newexpression for blood pressure changing was deduced. The transformation between thefingertip pulsed wave signal and brachial artery pulse wave signal was determined bycorrection process. with the help of linear fitting method, equations were listed to get R,C and L value, which made diastolic blood pressure could be calculated. Compare thefirst method, the second method has a higher measurement accuracy and suitable forrealization on computer platform which has more calculation ability.4. Anti-interference oxygen saturation calculation method with810nm and660nmwavelength light source. Using the810nm wavelength light source instead of thetraditional940nm light source. Which reduce the systematic errors in ordinary oxygensaturation measurement. Under the new light source wavelength, a anti-jammingalgorithm based on adaptive filter was proposed. According to the experiment results, themeasurement accuracy of the anti-jamming algorithm is better than the ordinary method,especially when there was movement interference in pulse wave signal. A highly integrated wearable instrument for physiological parameter monitoring which issuitable for specialty hospitals and single person was studied and implemented in this paper. Thedynamic monitoring of the ECG signal, blood pressure, oxygen saturation, pulse rate wererealized by new methods, which make up for the deficiencies of the existing cardiovascularparameter monitoring. The actual test results showed that the accuracy of the test results ofinstrument's measurement was met the promotion standards. This paper provides a means ofachieving a new medical system which combines of the professional medical service and homehealth care. And it is also provides methods for the early detection and diagnosis forcardiovascular disease.
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