Wireless C45 Based Vital-Signs Monitoring System for Patient after Heart Operation Care

Transcription

1 Wireless C45 Based Vital-Signs Monitoring System for Patient after Heart Operation Care S.NOIMANEE*, T.TUNKASIRI**, K.SIRIWITAYAKORN**, J.TUNTRAKOON** * Department of Computer Engineering, Biomedical Engineering Centre Chiang Mai University, and National Electronics and Computer Technology Center (NECTEC) 239 Huay Kaew Road, Chiang Mai 50200, Thailand. Tel: ** Department of Physics, Chiang Mai University, 239 Huay Kaew Road, Chiang Mai 50200, Thailand. Tel: tawee@chiangmai.ac.th, kingkeo@chiangmai.ac.th, j-rapong@chiangmai.ac.th Abstract: The use of vital-signs monitoring to detect patient vital signs with the intent to prevent patients dead after heart operation falls. This paper presents mobile patient monitoring system laboratory prototype, which provides patient electrocardiogram signals transferring via mobile extension technology with old version mobile phone in Thailand. At the patient s location, a wireless old mobile phone C45-based monitor is used to acquire continuously the patient s vital signs, including heart rate, standard-lead electrocardiography, etc. The system has been evaluated by physician verification and laboratory test. Through the mobile extension services in Thailand, the patient s vital signs signals can be transmitted in real-time to a central management unit, and authorized medical staffs or physician can access the ECG wave form, data and the case history of each patient by mobile personal digital assistant or PC trough Wi-Fi technology, either by the central management unit or the wireless devices. The results were that the prototype reduced the risk of heart attack by 15%. Most benefit was due to 30% drop in the risk of heart-related death. Their also show that the mobile PDA is superior to the currently used monitors both in mobility and in usability, therefore, better suited to patient transport. Keywords: Vital Signs monitoring, C45-based monitor, ECG waveform, Wi-Fi technology, heart attack. Introduction Patient electrocardiogram transmitting has been particularly useful for monitoring cardiovascular system s conditions. At present days infrastructure of internet and mobile extension system in Thailand has opened a new transmission media which establishes access to many data base at very low coasts. With the means of intelligent agents, monitoring and heart failure prevention sessions can be greatly enhanced and coast lowered. Real-time vital signs transmission via cellular phone system has been important in order to provide direct access to expert doctor in remote area to coronary care unit patient monitoring and to check patient s conditions at any place zone or patient home area after his/her operated. This paper describes a complete laboratory prototype real-time vital-sign monitoring system via mobile extension system. The design includes an ECG hardware card, a communicator for transferring the ECG data and automated software with can record and monitor the received data on cardiac care unit site. System Description Vital signs transmitting has given as in Figure 1. For only laboratory prototype of vital sign transmitter with given in Figure 2. By the way, Figure 3 shows block diagram how to display on PDA s screen. The ISSN: Page 239 ISBN:

2 function of each one of components of the proposed transmission system and detail will be described in the following sessions. This paper presents a design of laboratory prototype MCS89C2051 microcontroller based transmission system capable of realtime vital signs monitoring via mobile extension system in Thailand. converter (PIC12F675), control unit (Microcontroller MCS89C2051) and interface chip (DS275). The sampling rate can be set from 100 to 500 sample per second. Figure 1. Structure of vital sign monitoring system 5 1 Differential Amplifier I Body Temperature sensor Digital Communication 6 14 C-55 Differential Amplifier II Cellular phone F675 8 Bits ADC Microcontroller CD4066 Modulator 89C2051 Cellular phone controller microcontroller DS-275 Communicate to Mobile Phone Mobile Data Link cable Differential Amplifier III DB-9 To Cellular phone 3 Data Acquisition Module Interface to Cellular phone PCG Sensor Differential Amplifier LPF 40 Hz 4.5KHz Analog signal conditioners Figure 2. Block diagram of LAB prototype of vital signs transmitter The system was designed for laboratory prototype into implementation the requirements of patients after heart operation. Basically, it has some properties, including low noise amplifier circuit with low power consumption cost. A preamplifier in biopotential measurements is a direct couple fully differential amplifier followed by a differential amplifier, as the three operational amplifier. It was build from instrument amplifier or INA family, such as INA126 or INA128, driver right leg, and guard driving circuits. The overall gain is set to 500. For DC power supply, we was use small size of 12V batteries. Figure 6 shows a simple of vital signs, such as ECG output (Standard Lead) by prototype system. The digital transferring section consist of the data Figure 3. Flowchart of output shows on PDA s screen Transferring module In this module, MCS89C2051 microcontroller MCS, and DS275 interface are chosen. The connection rate of the MCS with old version mobile phone C45 is 19,200 bps. Since we have used C45 mobile phone, standard baud rate was set to 19,200. DS275 interface IC chip performs a proper connection between C45 mobile phone data terminal with DB-9 standard and MCS. The transferring units are shown in Figure 2 and Figure 4. ISSN: Page 240 ISBN:

3 In the path of receiver, the other mobile phone is connected to serial port of host computer via it data cable as shown in Figure 8. Figure 4. Transferring module of patient Figure 5. Output of ECG amplifier for standard lead. Figure 8. Path of receiver of system connected to serial port of host computer Figure 6. Main page shows on PDA screen Figure 7. Output shows on PDA screen for standard lead. Now for, the Delphi 7 based software is employed for communication between receiver mobile phone and host computer. The properties of this software as follows: Opening task the system and setting of waiting position. Receiving task according to calling device. Reply to calling and connecting. Monitoring and recording vital signs such as ECG data. Anyhow, the flowchart of microcontroller s software and Delphi 7 based software are shown in Figure 3. Results In order to test of system performance, we performed a trial about acquisition of ECG from a healthy male subject, 20 year old. The main objective of the test was to verify the functioning of the system by acquiring clinically acceptable ECG signals. Execution of transmission application generates the graphic user interface (GUI) as shown in Figure 6 and 7. Interface can be divided in some main sections. At the bottom, seven elements are shown, which allow controlling the ISSN: Page 241 ISBN:

4 transmission process. While system is ON state, receiver mobile phone opens it related port, hence it waits for calling. After reasonable waiting, the connection of both systems (i.e. receiver and transmitter) can be performed. The baud rate of the connection can be observed in connection window. When the connection is performed, the pilot of coming signal will be appeared in graphic window. After completing transferring process, the system passed to waiting state, again. Mean while, the coming vital signs such as ECG signal can be recorded at relate file, as well. Conclusions The design of complete real-time vital signs monitoring for patient after heart operation has the following properties: transmission (portable/holter equipment), storage, and receiver visualization that is easy to use and dedicated for patient, has been developed can be used autonomously, with the serial interface with C45 mobile phone, or as a modulator equipment in conjunction with the demodulator one. The main target of this prototype consist of providing customers a tele-assistance service with 24 hours at Chiang Mai medical center. The connection between transmitter (at patient) and receiver (Hospital server) are easily accomplished. For information safety, a data coding facility might be desirable. In the future, receiver application could include more sophisticated signal processing techniques and interpretative software. Acknowledgments The authors thank National Electronics and Computer Technology Center (NECTEC) for his invaluable assistance in funding my every research, and Biomedical Engineering Centre Chiang Mai University. This work was supported by Department of Computer Engineering and Biomedical Engineering Center, Chiang Mai University, Chiang Mai, Thailand. 7. References [1] (The Health Information, Division of Policy and Strategy, Office of Ministry of Health, Thailand ) [2] B. Andersen and C. Baker, A new era in HVDC, Power systems magazine, march 2000, pp [3] Charies A.Harper Electronic Materials and Processes Handbook, second edition, McGraw-Hill, Ins. Pp [4] Clyde G. Oakley, Design considerations for 1-3 Composites Used in Transducers for Medical Ultrasonic Imaging, Wayne Hueber and Kuiming Liang, Pensyvania State University, Materials Research Laboratory, University Park, PA IEEE journals, pp [5] James Welch., Farzin Guilak., Steven D. Baker. A Wireless ECG Smart Sensor for Broad Application in Life Threatening Event Detection, Proceedings of the 26th Annual International Conference of the IEEE EMBS San Francisco, CA, USA. September 1-5, pp [6] Burk, M.J. and Glee, D.T. An Ultra- Low Power Pre-Amplifier for Pasteless Electrocardiography, Electrical and Electronic Circuit., IEEE journal, pp [7] Takashi Handa, Shuich Shoji, ShinichiIke, Sunao Takeda and Tetsushi Sekiguch. A Very Low-Power Consumption Wireless ECG Monitoring System Using Body as a Signal Transmission Medium, 7997 lnternational Conference on Solid-State Sensors and Actuators Chicago, June 16-19, 1997 [8] F Chiarugi, M Spanakis, PJ Lees1, CE Chronaki, M Tsiknakis, SC Orphanoudakis ECG in Your Hands: a Multi-Vendor ECG Viewer for Personal Digital Assistants, CMI-HTA, Institute of Computer Science, foundation for research and technology-hellas, ICS- FORTH, Heraklion, Crete, Greece and department of Computer Science, ISSN: Page 242 ISBN:

5 University of Crete, Heraklion, Crete, Greece. [9] K. Hung and Y.T. Zhang Usage of Bluetooth TM in Wireless Sensors for Tele-Healthcare, Proceedings of the second joint of EMBS/BMES Conference, Houston, TX, USA. October 23-26, pp [10] Ricardo Isais, Khoi Nguyen, Gabriel Perez, Roberto Rubio, and Homyoun Nazeran A Low-cost Microcontrollerbased Wireless ECG-Blood Pressure Telemonitor for Home Care, Proceedings of the 25'" Annual International Conference. [11] Mehmet Engin, Yalcin Yamaner, Erkan Zeki Engin A biotelmetric system for human ECG measurements, Available online at Measurement 38(2005) ISSN: Page 243 ISBN: