Study on the accuracy of cardiopulmonary physiological measurements by a wearable physiological monitoring system under different activity conditions / 生物医学工程学杂志

This paper aims to study the accuracy of cardiopulmonary physiological parameters measurement under different exercise intensity in the accompanying (wearable) physiological parameter monitoring system. SensEcho, an accompanying physiological parameter monitoring system, and CORTEX METALYZER 3B, a cardiopulmonary function testing system, were used to simultaneously collect the cardiopulmonary physiological parameters of 28 healthy volunteers (17 males and 11 females) in various exercise states, such as standing, lying down and Bruce treadmill exercise. Bland-Altman analysis, correlation analysis and other methods, from the perspective of group and individual, were used to contrast and analyze the two types of equipment to measure parameters of heart rate and breathing rate. The results of group analysis showed that the heart rate and respiratory rate data box charts collected by the two devices were highly consistent. The heart rate difference was (-0.407 ± 3.380) times/min, and the respiratory rate difference was (-0.560 ± 7.047) times/min. The difference was very small. The Bland-Altman plot of the heart rate and respiratory rate in each experimental stage showed that the proportion of mean ± 2SD was 96.86% and 95.29%, respectively. The results of individual analysis showed that the correlation coefficients of the whole-process heart rate and respiratory rate data were all greater than 0.9. In conclusion, SensEcho, as an accompanying physiological parameter monitoring system, can accurately measure the human heart rate, respiration rate and other key cardiopulmonary physiological parameters under various sports conditions. It can maintain good stability under various sports conditions and meet the requirements of continuous physiological signal collection and analysis application under sports conditions.

Study on perceived fatigue evaluating model during simulated load carriage / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a perceived fatigue evaluating model during simulated load carriage that is based on objective variables through analyzing the characteristics and trends of shoulder force, shoulder pressure, waist pressure, back pressure, and perceived fatigue, and to provide an analytical technique for research on load carriage.</p><p><b>METHODS</b>A 50-min simulated walking (at a speed of 5 km/h and a slope of 0%) experiment including 14 healthy male adults was conducted under four levels of backpack payloads (25, 29, 34, 37 kg). Shoulder force and trunk pressure were sampled simultaneously and analyzed with time- and frequency- domain methods. Multivariable linear regression was used to build a perceived fatigue evaluating model during load carriage.</p><p><b>RESULTS</b>The perceived fatigue evaluating model based on shoulder force, trunk pressure distribution ratio, load, and body mass index (BMI) was established. Its adjusted determination coefficient (aR2) was 0.709 and the absolute percentage error (APE) at the end of the experiment was less than 20%. The goodness of fit of the model based on frequency-domain independent variables was much higher compared with the model based on time-domain independent variables. The addition of BMI that represents the individual differences to the model obviously improved the goodness of fit.</p><p><b>CONCLUSION</b>The perceived fatigue evaluating model established in this study does not rely on the physiological changes of individuals, and thus can be used to establish an evaluation system for human load carriage with dummy as a substitution for human in experiments and to provide a scientific basis for efficient human load carriage.</p>

Manual chest compression depth estimation based on integration reset mechanism / 生物医学工程学杂志

To realize the measurement of the chest compression depth during the administration of manual cardiopulmonary resuscitation, two 3-axis digital accelerometers were applied for chest compression acceleration and environment acceleration acquisition, with one placed in the chest compression sensor pad, and the other placed in the back sensor pad. Then double integration was made for the acceleration-to-depth conversion with both of the accelerations after preprocessing. The method further included integration reset mechanism based on compression force, with the force point of a pre-determined threshold and the maximum force point as the starting point and the ending point of the integration, respectively. Moreover, a software compensation algorithm was implemented to further increase the accuracy of the depth estimation and reliability of the acceleration. The final performance of the compression depth estimation is within +/- 0.6 cm with 95% confidence of a total of 283 compressions. Accurate and real-time estimation of chest compression depth greatly facilitates the control of compression depth for the lifesaver during manual cardiopulmonary resuscitation.

Comprehensive testing system for cardiorespiratory interaction research / 生物医学工程学杂志

To investigate the modulation effects of breathing movement on cardiovascular system and to study the physiological coupling relationship between respiration and cardiovascular system, we designed a comprehensive testing system for cardiorespiratory interaction research. This system, comprising three parts, i. e. physiological signal conditioning unit, data acquisition and USB medical isolation unit, and a PC based program, can acquire multiple physiological data such as respiratory flow, rib cage and abdomen movement, electrocardiograph, artery pulse wave, cardiac sounds, skin temperature, and electromyography simultaneously under certain experimental protocols. Furthermore this system can be used in research on short-term cardiovascular variability by paced breathing. Preliminary experiments showed that this system could accurately record rib cage and abdomen movement under very low breathing rate, using respiratory inductive plethysmography to acquire respiration signal in direct-current coupling mode. After calibration, this system can be used to estimate ventilation non-intrusively and correctly. The PC based program can generate audio and visual biofeedback signal, and guide the volunteers to perform a slow and regular breathing. An experiment on healthy volunteers showed that this system was able to guide the volunteers to do slow breathing effectively and simultaneously record multiple physiological data during the experiments. Signal processing techniques were used for off-line data analysis, such as non-invasive ventilation calibration, QRS complex wave detection, and respiratory sinus arrhythmia and pulse wave transit time calculation. The experiment result showed that the modulation effect on RR interval, respiratory sinus arrhythmia (RSA), pulse wave transit time (PWTT) by respiration would get stronger with the going of the slow and regular breathing.

Computer simulation study on physiological feedback parameters during chest compression / 生物医学工程学杂志

To have a thorough understanding of the CPR quality based on patients' various physiological states, the doctors must do something to simulate the chest compression physiological feedback parameters (CCPFP). The CCPFP simulation plays an important role in raising efficiency of CPR training and improving chest compression quality. In this study, the CCPFP, including cardiac output (CO), coronary perfusion pressure (CPP), partial pressure of End-tidal CO2 (PETCO2) and mean arterial relaxation pressure (MARP), was simulated using Charles F. Babbs' Model. Simulation results showed that the effect of compression depth upon CCPFP was important in the range of 2-6 cm, whereas compression rate had little effect on the CCPFP higher than 100/min; the thoracic factor is inversely proportional to the CCPFP with fixed compression depth and compression rate. The CCPFP simulation can be implemented at the various physiological statuses, and verified well with the animal experimental results and the clinical results.

Wearable Concurrent Monitoring System for Physiological Parameters / 航天医学与医学工程

Objective To design a wearable physiological monitoring system for acquiring and monitor-ing vital signs non-intrusively and concurrently.Methods All bio-sensors were embedded in an elastic shirt for detecting physiological parameters with wearable technology.A patented respiratory inductive plethysmography technology was used to measure respiratory function,two sensors were woven into the jerkin around the patient's chest and abdomen.A three-lead,single channel ECG measures heart rate,and a three-axis accelerometer records posture and activity level.An NTC thermometer embedded in the shirt measures the body temperature.Results An elastic jerkin with embedded sensors that collect and continuously monitor respiration,cardiac,temperature,posture and activity signals was fabricated.Conclusion This wearable physiological monitoring system can record multiple parameters non-intrusively and concurrently.It can act as an useful platform for further researches.

The portable low power military ECG for triage / 医疗卫生装备

The military portable ECG for triage is a kind of minitype monitoring equipment for life information for the purpose that the ambulanceman carry through first aids in frontline. Life information of the wounded will be acquired exactly and quickly applying with this equipment, then quickening the triage and reducing the casualties. The system is based on C8051F310 single chip microcomputer, applying with high accuracy, low offset drift instrumentation amplifier AD620 and ultra low power LCM LMS019 to display real-time and accurate ECG signal sampled. The equipment is easy to use and inexpensive, suitable for mass requirement of our field army.

Detection and monitoring technologies for life signals / 医疗卫生装备

The detection and monitoring of life signals such as heartbeat, respir ation, bloodpressure and temperature are often used to determine the patient's death. On the basis of the theory of military medical service, this paper discus ses life signals detection and monitoring technologies in the field of military medicine. With the progress of sciences, technologies and informatization of Chi nese PLA, life signals detection and monitoring technologies, based on informati on technology, microelectronic technology, communication technology and etc, wil l be more and more important in the development of digital medical equipment.