[Design of Portable Noninvasive Positive Pressure Ventilator System Based on Threshold Trigger of Flow Rate Change].

In order to effectively treat respiratory diseases, a non-invasive positive pressure ventilator system is designed, the overall structure design of the system is proposed, and the hardware construction is completed. The breathing state of the patient is identified by the threshold triggering method of the flow rate of change, and the calculation of the flow rate of change is realized by the least squares method. At the same time, the breathing parameters are calculated in real time according to the flow-time and pressure-time characteristic curves. In addition, CMV, CPAP, BiPAP and PSV ventilation modes are also implemented. Finally, the parameter measurement accuracy and ventilation mode setting tests are carried out. The results show that the calculation of key breathing parameters provided by the system meets the relevant standards, and supports the stable output of 4 ventilation modes at the same time, provides breathing treatment for patients, and meets the basic functional requirements of the ventilator.

[Research and Development Trend of Medical Oxygen Production Equipment].

Oxygen therapy is an effective clinical method for the treatment of respiratory disorders, oxygen concentrator as a necessary medical auxiliary equipment in hospitals, its research and development has been a hot spot. The study reviewed the development history of the ventilator, introduced the two preparation technique of the oxygen generator pressure swing absorption (PSA) and vacuum pressure swing adsorption (VPSA), and analyzed the core technology development of the oxygen generator. In addition, the study compared some major brands of oxygen concentrators on the market and prospected the development trend of oxygen concentrators.

[Research on ICG Signal Preprocessing and Feature Recognition Method Based on CEEMDAN].

A method based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) combined with differential, threshold iterative processing and signal segmentation is proposed to preprocess the impedance cardiogram (ICG) signal and identify multiple feature points. First, CEEMDAN decomposes the ICG signal to obtain multiple modal function components (IMF). According to the highfrequency and low-frequency noise frequencies existing in the ICG, the correlation coefficient method is used to remove the interference noise, and then the ICG signal after noise removal is differentiated and segmented. Looking for feature points B, C, X, and perform the above processing on the signals of 20 volunteers collected clinically to evaluate the accuracy of the algorithm. The final results show that the method can locate the feature points with an accuracy rate of 95.8%, the feature positioning effect is good.

[Design and Implementation of Urodynamic Monitoring System].

In order to assess and diagnose lower urinary tract dysfunction in patients and help patients with lower urinary tract rehabilitation training, an accurate and reliable urodynamic monitoring and automatic voiding system was designed. The system realizes the signal acquisition circuit of bladder pressure, abdominal pressure and urine volume based on the pressure sensor of urinary catheter and the load sensor. Meanwhile, the dynamic waveforms of urinary flow rate, bladder pressure and abdominal pressure are drawn in real time on the software of urodynamic monitoring. Signal processing and analysis of each signal are carried out, and the system performance is verified by building a simulation experiment. The experimental results show that the system is stable, reliable, accurate and meets the expected design goals, which can provide support for subsequent engineering design and clinical applications.

[An Adaptive Method for Detecting and Removing EEG Noise].

To solve the problem of real-time detection and removal of EEG signal noise in anesthesia depth monitoring, we proposed an adaptive EEG signal noise detection and removal method. This method uses discrete wavelet transform to extract the low-frequency energy and high-frequency energy of a segment of EEG signals, and sets two sets of thresholds for the low-frequency band and high-frequency band of the EEG signal. These two sets of thresholds can be updated adaptively according to the energy situation of the most recent EEG signal. Finally, we judge the level of signal interference according to the range of low-frequency energy and high-frequency energy, and perform corresponding denoising processing. The results show that the method can more accurately detect and remove the noise interference in the EEG signal, and improve the stability of the calculated characteristic parameters.

[Miniature Non-invasive Blood Pressure Measurement and Verification System].

Mercury sphygmomanometer based on traditional auscultation method is widely used in primary medical institutions in China, but a large amount of blood pressure data can not be directly recorded and applied in scientific research analysis, meanwhile auscultation data is the clinical standard to verify the accuracy of non-invasive electronic sphygmomanometer. Focusing on this, we designed a miniature non-invasive blood pressure measurement and verification system, which can assist doctors to record blood pressure data automatically during the process of auscultation. Through the data playback function,the software of this system can evaluate and verify the blood pressure algorithm of oscillographic method, and then continuously modify the algorithm to improve the measurement accuracy. This study introduces the hardware selection and software design process in detail. The test results show that the system meets the requirements of relevant standards and has a good application prospect.

[Development Progress of Ventilator].

Ventilator is an indispensable emergency medical equipment in hospitals. The global outbreak of the coronavirus disease 2019 (COVID-19) has highlighted the importance of the ventilator, which has attracted the attention and research on ventilators of all countries in the world. This article reviews the development history of the ventilator, briefly introduces the main air circuit structure and working principle of the ventilator, and then deeply analyzes the key technologies of this device. In addition, it compares some major brands of ventilators from several aspects in the market. Finally, the development trend and perspective of ventilators are presented.