| Objective: Cardiac arrest exists on anybody, and can take place at any time and any place. Only the patients rescued by timely and effective cardiopulmonary resuscitation(CPR) have the chance to survive. As an important part of CPR, chest compression is a key technology and a key link of the early CPR and the first aid. In some special cases, it even becomes the only effective measure. However, numerous studies abroad showed that the majority of chest compressions operated by non-professional rescuer are not ideal, and so did the professional rescuers. For the purpose of maintaining the proper and the effective chest compressions, rescuers need to establish and promote the chest compressions feedback monitoring technology which applies the feedback mechanism and supplies the accurate real-time feedback. In order to find an efficient way to monitor chest compressions and offer a real-time feedback to rescuers, we did an in-depth analysis about chest compressions feedback monitoring technology, and designed a set of chest compressions feedback monitoring system (CCFMS). This system can quickly and accurately assess the state of chest compressions and guide the rescuers to offer the effective and high quality chest compressions. Ultimately, we designed and created a chest compressions feedback monitoring system and provided an intelligent solution for the effective chest compressions.Methods: Chest compression monitoring and feedback technology mainly focus on chest compression verticality, compression depth, compression pressure, compression frequency and ECG of patients. With the three-axis acceleration sensor, we established a chest compression verticality detection algorithm and a acceleration quadratic integral algorithm to detect the direction and the depth of chest compression in real time. With the micro-pressure sensor and the related amplifying and filtering circuits, the chest compression pressure is detected continuously. In addition, with the peak detection algorithm detecting the peak of compression waveform, the compression frequency was obtained . In order to provide rescuers with the accurate physiological state of patient, ECG of patients were sampled by the ECG sampling module with high CMRR. Chest compression depth and pressure measurement experiments were carried out to assess the accuracy and reliability of detection result. Finally, based on laerdal PC SkillReporting System experimental platform, the efficiency of chest compression was evaluated, which involved the indexes as the compression pressure, depth, frequency, interruption time, completely releases and verticality.Contents: This paper includes the following work:. System hardware design and implementation. In order to design chest compression acceleration detecting module, a reasonable accelerator has been chosen and filtering circuits have been implemented. At the same time, a reasonable pressure sensor, filtering circuits and amplifying circuits are also critical for design of chest compression pressure detecting module. ECG processing circuits, filtering circuits and amplifying circuits have also been designed to sample the ECG signal. In addition, the SD Card interface circuits and programs related with SD Card have been achieved as well. Human-Computer interaction module integrating LCD and a buzzer, which plays an important role in displaying, alarming and instructing, has been fulfilled. For the purpose of realizing the communication between feedback nodes and the wireless basic station, the wireless communication module has been designed and implemented. In the end, power-processing circuits, voltage stabilizing circuits and power management circuits were achieved.. Design and implementation of system algorithm, related softwares, and wireless basic station. Programs for sampling pressure sensor signal accurately and processing related data were compiled. With the relationship between accelerator's X-axis value and Y-axis value, the compression verticality was detected. Besides, the acceleration quadratic integral algorithm detecting compression depth was established, which includes the zero acceleration calibration, the trapezoidal integration method, the discrete quadratic integral algorithm and the integral process based on reset mechanism. Accurate ECG sampling, QRS wave detection pretreatment, accurate extraction of R peaks and heart rate detection were implemented. Moreover, in order to accomplish the pressure wave and ECG wave tracing point rendering, the proper programs resulting in the reasonable and effective interface and guiding rescuers to carry out the correct and timely chest compression were compiled, based on the well-known LCD working principle. Using wireless sensor module and software for wireless network, wireless communication between basic station and numerous feedback nodes was realized. Finally, the data of numerous chest compression feedback nodes were visually displayed on the wireless basic station interface based on VC++ 6.0.. System integration design. According to the integration design requirements which claim that the system should be portable, lightweight and compatible, we provided two integration design plans which are chest cushion plan and glove plan.. Assessment experiments for the reliability of system and efficiency of feedback and monitoring. In order to assess the accuracy and the reliability of detection results, Chest compression depth and pressure measurement experiments were carried out. Based on laerdal PC SkillReporting System experimental platform, chest compression efficiency was evaluated, which is concerned about the compression pressure, depth, frequency, interruption time, completely release and verticality. Achievements: In this paper, we established QRS wave detection algorithm, chest compression verticality detection algorithm, acceleration quadratic integral algorithm, chest compression sampling technology and chest compression frequency measurement algorithm, accomplished the real time feedback and monitoring for ECG signal, compression verticality, compression depth and compression frequency, and produced a prototype. In order to improve system's intelligence and information level, we added the wireless communication and the large-capacity data storage, and established the wireless basic station contributing to the effective analysis and estimation of related data. According to the integration design requirements which claim that the system should be portable, lightweight, and compatible, we provided two integration design plans which are chest cushion plan and glove plan and implemented the structure and function design of two kinds of chest compression feedback and monitoring equipments which are portable chest compression assisting monitoring cushion( Academy of Military Medical science, Institute of medical equipment, Patent number: ZL200820145171.3) and chest compression instructing glove ( Academy of Military Medical science, Institute of medical equipment, Patent number: ZL200820145170.9).Conclusions: This study provides an effective way to improve the chest compression and feedback monitoring technology. With the help of this system, rescuers can carry out the more efficient and higher quality operation and training. Even for the laypeople, the powerful human-computer interaction can guide them to carry out the effective chest compression. The experiments show that, compared with the conventional chest compressions, the quality of the present chest compressions with the chest compressions feedback monitoring system is significantly improved and enhanced. The chest compressions feedback monitoring system can provide patients with high quality basic life support(BLS), before the professional rescuers rush to the scene of emergency, and the success rate of CPR and survival rate can be effectively increased. |
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