| Severe Acute Respiratory Syndrome (SARS), a type of acute infectious disease of respiratory tract, is caused by SARS virus and spread through near flying spittle and close-contact. The infectious capability of SARS is strong and close-contact spread is one of important spread modes. In order to reduce the spread during monitoring period of SARS patients, it's so essential that a telemetry system is designed to monitor patients' ECG, temperature and blood pressure (BP) according to the spread characterist -ic of SARS.The hardware and part of software of the system are accomplished .1) The design requirements of ECG are discussed. According to the requirements, ECG amplifier is designed. ECG signal is derived from lead â…¡and sampling frequency is 250 Hz.2) Temperature value is taken by AD590.In order to improve the measurement precision, the nonlinear compensation methods are discussed and the problem which should be paid attention to are presented. 3)BP is measured with EP806C BP module. Because of the different data format, a interface circuit receiving data is designed to correctly receive data. 4) ECG, temperature and BP are acquired with PIC16F877.The acquired data is sent by STR-6 wireless receiving-sending module. To increase reliability, the method sending data by way of frame unit is put forward. The anti-jamming problem of hardware design is discussed. 5) Another STR-6 module receive data and send them to PC through serial port. 6) The data acquisition program module is programmed with DELPHI. Part of the program module is implemented with API function, which is simple and reliable. The multi-thread method is used to keep the ECG show and data acquisition synchronization. 7) Detection of QRS is the key of ECG automatic analysis, so differential algorithm is implemented with DELPHI. As the further study, QRS detection algorithm based on wavelet transform is researched. By the comparison of different wavelet function, cubic spline wavelet is selected to detect QRS and the detection ratio is up to 99.02%.ECG simulator is used to test the ECG part of the system, the experimental results show that this system's actual telemetry distance reaches 30 meter at different room of the same floor within an average building. Also, the ECG waveform show is stable and the information of each parameter (include ECG, temperature and BP) is synchronous. In a word, Monitoring SARS patients' ECG and temperature using telemetry mode is feasible. By this method, the system can reduce the contact between medical personnel and SARS patients. So it can lessen the spread of SARS. At the same time, the system can be applied to multi-parameter monitoring and monitoring of acute infectious disease. |
