Discussion on Testing and Standard of Blood Pressure Sensor at the Tip of Catheter / 中国医疗器械杂志

With the implementation of the new policy for coronary stent centralized volume purchasing in China, the blood pressure sensor at the tip of the catheter, as one of the essential medical instruments for the diagnosis and treatment of coronary artery disease, will meet the new development opportunity of the industry, a number of medical device companies will actively participate in the development and registration of the catheter tip blood pressure sensor. As an invasive blood pressure sensor, the catheter tip blood pressure sensor should meet the current effective industry standard YY 0781-2010, however, there are many problems when using YY 0781-2010 as a blood pressure sensor because of the difference of product structure and working mode. In this paper, the problems about "Operation Manual", "electrical performance" and "safety requirement" in the course of carrying out YY 0781- 2010 with the blood pressure sensor on the tip of catheter are discussed and analyzed in detail, hope to provide some inspiration for more research and development enterprises of blood pressure sensors on the tip of catheters and inspectors of medical device testing institutions, also hope to be able to contribute to the high-quality development of blood pressure sensor industry at the tip of the Catheter.

Unconstrained Monitoring of Sleep Respiration Based on Detection of Pressure fluctuations on Mattress / 医用生物力学

Objective To develop a method for monitoring unconstrained sleep respiration suitable for daily use at home, so as to realize high precision screening of sleep apnea syndrome (SAS) or other respiratory diseases without affecting normal sleep. Methods A new unconstrained measurement method using sheet-type flexible pressure sensor was proposed. This method could obtain the information of respiratory motions of the chest and abdomen by measuring the pressure fluctuations of the chest and abdomen acting on the mattress. Experiments were conducted on ten healthy subjects to confirm effectiveness of the proposed method by comparing the result of the unconstrained measurement and those of respiratory inductance plethysmography (RIP) using band sensors, respectively. Results Sheet-type flexible pressure sensor could measure the pressure fluctuations of the chest and abdomen acting on the mattress during respiration and obtain respiratory waveform and respiratory rate. The respiratory rate measured with the sheet-type flexible pressure sensor agreed with those obtained by RIP. The gender and the lying position greatly affected whether the phases of the pressure fluctuations of the chest and abdomen measured with the flexible sensor differed from those obtained by RIP. The chest respiratory finite element model was established to analyze the phase difference of respiratory movement. Conclusions Sheet-type flexible pressure sensor is effective to monitor unconstrained sleep respiration, indicating the potential to identify the SAS types. But further researches of motion decoupling are required to identify the phase difference between the chest motion and the abdomen motion, which are coupled with each other.

Mechanism of "herb soaking with exact amount of water" during moistening process of ginseng based on needle pressure sensor / 中国中药杂志

In this study, the texture analyzer acupuncture pressure sensor was used to objectively characterize the "herb soaking with exact amount of water" for moistening process of ginseng. The single factor rotation experiment was used to investigate the effects of puncture speed, puncture depth and puncture site on puncture force and work. According to ginseng processing method in Chinese Pharmacopoeia, ginseng medicinal materials with diameters of about 1 cm and 2 cm were selected, and puncture experiments were carried out at the set measurement time to determine the hardness, work and water absorption of the ginseng moistening process. The endpoint threshold for the ginseng softening process was determined and verified. To reflect the actual internal conditions of the ginseng softening process, the puncture depth was preferably 70%, and the puncture speed was 30 mm·min~(-1). In the ginseng moistening process, the softening hardness and the puncture work were in accordance with the first-order kinetic equation y=a×exp(-k×x). The 0 h initial hardness a of 1 cm and 2 cm ginseng herbs were 289.8 N and 1 227 N, and the rate constants K were 0.149 4 N·h~(-1) and 0.100 7 N·h~(-1), respectively. After the ginseng was completely softened, the force required for puncture was 10 N, which can be used as the standard for "drug penetration". At this time, the water absorption rate of ginseng was 70%-100%. The softening time of ginseng with a diameter of 1 cm was about 20-22 h, and the softening time of ginseng with a diameter of 2 cm was about 40-46 h. A needle-type pressure sensor was used to accurately determine the end point of the softening process of ginseng and reduce the loss of active ingredients. The study results provide reference for the softening process kinetics and the process intelligent monitoring of other dried roots and rhizomes.

The effect of adaptation of two pressure sensors on the pediatric liver transplantation / 中国实用护理杂志

Objective@#We observed the effect of the opening and closing pressure sensors on the pediatric liver transplantation.@*Methods@#The 100 cases of pediatric patients who suffered biliary atresia were chose to this study from July 1st 2018 to Dec 31st 2018. They received the living donor liver transplantation. The samples were divided into control group and test group according to the random number table. We observed the volume of blood lost during the process of blood sample collecting. The hemoglobin (HB) and infection rate of catheter were also recorded.@*Results@#The test group didn′t lose blood when collecting the sample, and the time of collecting the blood sample in the test group was (22.0 ± 4.2) s, which was shorter than that of in the control group (47.0 ± 7.8) s, the difference was significant, t=9.321, P<0.05. The difference of HB and infection rate of catheter after 24 hours between two groups was not significant, P>0.05.@*Conclusion@#The closing pressure sensor may be more advanced when used to avoid the loss of blood and prevent the infection.

Development of a Novel Intraoperative Neuromonitoring System Using a Surface Pressure Sensor to Detect Muscle Movement: A Rabbit Model Study

OBJECTIVES: False-negative or false-positive responses in intraoperative neuromonitoring (IONM) using electromyography (EMG) in thyroid surgery pose a challenge. Therefore, we developed a novel IONM system that uses a surface pressure sensor instead of EMG to detect muscle twitching. This study aimed to investigate the feasibility and safety of a new IONM system using a piezo-electric surface pressure sensor in an experimental animal model. METHODS: We developed the surface pressure sensor by modifying a commercial piezo-electric sensor. We evaluated the stimulus thresholds to detect muscle movement, as well as the amplitude and latency of the EMG and surface pressure sensor in six sciatic nerves of three rabbits, according to the stimulus intensity. RESULTS: The surface pressure sensor detected the muscle movements in response to a 0.1 mA stimulation of all six sciatic nerves. There were no differences in the thresholds of stimulus intensity between the surface pressure sensor and EMG recordings to detect muscle movements. CONCLUSION: It is possible to measure the change in surface pressure by using a piezo-electric surface pressure sensor instead of EMG to detect muscle movement induced by nerve stimulation. The application of IONM using a piezo-electric surface pressure sensor during surgery is noninvasive, safe, and feasible. Measuring muscle twitching to identify the state of the nerves using the novel IONM system can be an alternative to recording of EMG responses.

Monitoring intra-abdominal pressure to assist enteral nutrition supporting treatment for patients with high risk of IAH/ACS / 肠外与肠内营养

Objective:To evaluate the practical application of intra-abdominal pressure (IAP) monitoring product in patients receiving enteral nutrition (EN) and with high risk of intra-abdominal hypertension/abdominal compartment syndrome (IAH/ACS).Methods:Patients receiving EN treatment from Changzheng hospital were randomly divided as experimental group (measuring IAP with pressure monitoring product,n =60) and control group (measuring IAP with conventional method,n =60).The clinical data of gastrointestinal complications,gastric residual volume,IAP and completion of target infusions were collected and analyzed.Results:The incidence of gastrointestinal complications in experimental group patients significantly decreased comparing with the control group patients (7.92％ vs 28.33％,P ＜ 0.01).The levels of gastric residual volume and IAP in experimental group patients were lower than those in control group patients[(50.12 ± 10.66) ml vs.(101.54 ± 25.81) ml,(7.17 ± 1.84) cmH2O vs (12.36 ± 2.51) cmH2O,P ＜0.05].Moreover,The experimental group patients had a shorter period to achieve target infusions and higher proportion of completion treatments [88.3％ vs 71.7％,(2.94 ± 0.78)d vs (3.78 ± 1.02)d,P ＜ 0.05)].Conclusion:As utilizing pressure monitoring products to assist EN treatment for patients with high risk of IAH/ACS could achieve lower incidence of gastrointestinal complications,excellent EN tolerance,and improve target feeding,its clinical application should be extended.

Development and Application of Fiber-optic Pressure Sensor in Medical Field / 中国医疗器械杂志

pressure monitoring is important for monitoring of organ or tissue lesions and real-time analysis of intraoperative conditions. Compared with the traditional electromechanical pressure sensor, the optical fiber pressure sensor has the advantages of small size, high sensitivity, high safety and strong ability of resisting electromagnetic interference. It has been widely applied in the medical field. This thesis reviews the development of optical fiber pressure sensors and the application of pressure monitoring in the medical field. It emphatically analyses the monitoring of the optical fiber pressure sensor in cardiovascular and blood, intracranial, airway, gastrointestinal tract and other tissues or organs. Analysis shows that the favorable result of monitor can be got using optical fiber pressure sensor in different tissues or organs.

Analysis of behavior of forces in a pelvis-soft tissue mechanical model / Análisis del comportamiento de fuerzas en un modelo mecánico de pelvis-tejido blando

Pressure ulcers are tissue damage resulting from the constant pressure on the underlying soft tissue to bony prominences for long periods. Some of the most common ulcers are developed at the ischial tuberosities area (ITs). It has been found that stresses produced in the underlying tissue to the ITs may exceed 5 to 11 times the surface stresses, making it necessary to estimate the forces generated between the soft tissue and the ITs. However, it is not possible to determine these stresses in vivo in a patient, due to ethical reasons. This paper presents a mechanical model of the pelvis-soft tissue in order to study the behavior of contact forces. The model simulates the load on the ITs of a male subject of 70 kg weight and 1.70 m height, which were recorded for 8 min. The registered forces in the model were compared with the surface forces estimated from pressure records measured by the Force Sensing Array system in a patient with spinal cord injury. After 2 min, both forces measured in the model, and the ones estimated in the patient followed the trend described by Crawford during clinical measurements of pressures during sitting. It was also found in the model that measured forces below the ITs are higher than those measured below soft tissue, which suggests that the model may be valid for the study of the forces generated inside the tissue.

Las úlceras por presión son daños en el tejido, derivados de la presión constante por periodos prolongados sobre el tejido blando subyacente a una prominencia ósea, algunas de las úlceras más comunes se desarrollan en la zona de las tuberosidades isquiáticas (TI´s). Se ha detectado que esfuerzos generados en el tejido subyacente a las TI´s pueden exceder entre 5 a 11 veces a los esfuerzos superficiales, lo que hace necesario conocer las fuerzas que se generan entre el tejido blando y las TI´s, sin embargo medir estos esfuerzos in vivo en un sujeto, no es posible por razones éticas. Este trabajo presenta un modelo mecánico del sistema pelvis-tejido blando con la finalidad de estudiar el comportamiento de las fuerzas, el modelo simula la carga en las TI´s de un sujeto masculino de 70 kg y 1,70 m, en el cual se registraron por 8 min. Las fuerzas registradas en modelo fueron comparadas con las fuerzas superficiales estimadas a partir de los registros de presión medidas por el sistema Force Sensing Array, en un paciente con lesión medular. A partir de 2 min, tanto fuerzas medidas en el modelo, como estimadas en el paciente, siguen la tendencia descrita por Crawford para mediciones de presiones clínicas durante la sedestación, también se encontró en el modelo que las fuerzas medidas por debajo de las TI's son mayores a las medidas debajo del tejido blando; lo que sugiere que el modelo puede ser válido, para el estudio de las fuerzas que se generan al interior del tejido.

Development of intelligent pneumatic tourniquet / 医疗卫生装备

Objective To develop an intelligent pneumatic tourniquet to reduce the complications due to manual operation.Methods The tourniquet was composed of two parts of tourniquet and electronic processor.The electronic processor involved in the pressure sensor,data processor,electronic display and alarm device.Moving average and frequency domain filtering algorithms were used to design signal processing.Results The tourniquet gained advantages over the traditional one in patient comfort,hemostatic efficacy and complications.Conclusion The tourniquet increases the safety while decreases the complications due to manual operation,and thus is worthy promoting clinically.

A design and analysis of a monitoring system for muscle relaxation / 中国医学装备

Objective:To design and analyze a muscle relaxation monitoring system so as to increase the anesthesia efficiency and safety.Methods: The hardware design of system was based on single chip machine (STC89C52RC), and it has the function of LCD real-time display for pressure change and the printing function. The design of software mainly included the system main program design, pressure sensor subroutine, A/D conversion subroutine, LCD real-time display subroutine and printer subroutine, etc.Results:Through the multiple times of test and improvement for the system, the system has achieved stably run, and the pressure value could achieve accurately display between 0-100N.Conclusion: The monitoring system of muscular relaxation has series of advantages, such as simple circuit design, low cost, higher reliability and practicability and so on. It can real-timely and effectively monitor the change of the indexes of muscular relaxation for patients during operation. And the anesthesiologist can effectively control and change medication for patients. In this way, the monitoring system can increase the anesthetic efficiency and decrease the incidence of postoperative residual muscle relaxant.

Research on Solid Pressure Sensor for High-pressureMeasurement Based on Fiber Bragg Grating / 分析化学

Solid internal pressure is one of the important parameters in traffic bridge and defense field.However, the existing testing equipments have the defects of serious electromagnetic interference, poor reliability, and poor accuracy.To overcome the above problems, a fiber bragg grating (FBG) high pressure solid pressure sensor which used thin plates as elastic bearing diaphragm and applied the deflection under pressure to pull the pressure sensitive grating to realize pressure sensing axial displacement was designed.By calculating on the structure according to the measurement range and finite element simulation, its feasibility was confirmed.In the laboratory with constant temperature, the pressure calibration experiment was carried out, and the temperature compensation was performed by the temperature compensation grating in the same temperature field to correct the temperature drift of strain grating.Experimental results showed that the newly devised FBG pressure sensor could sense the pressure as high as 50 MPa, with a linearity of 99.2%.

Clinical application of continuous central venous pressure monitoring / 中国实用护理杂志

Objective To study the clinical effect of continuous central venous pressure monitoring and select a better method for central venous pressure momtoring. Methods Continuous central venous pressure wag monitored by connecting pressure sensor to central venous catheter in 56 patients with open heart operation.At the same time routine monitoring method was used in the same central venous vein of the saine patient The CVP values from the two methods were compared for 100 times and analyzed the difference.Results The VCP values of the two groups had no statistical difference(P＞0.05).Conclusions Continuous monitoring by pressure sensor had advantages such as continuous data,dynamic,direct-viewing,Veracious and decreased chance of infection.It could reduce the workload of nurses and possessed more clinical value compared with routine monitoring method.

Measurement and clinical application of normal plantar pressure / 中国矫形外科杂志

[Objective]To develop a mini-pressure-sensor(MPS)for measurement of plantar pressure(PP)and to evaluate its clinical application.[Method]The MPS was installed in the shoes,and computer was used to accumulate and analyze the change of PP in whole walking stage.Pathologic changes of PP in clinical patients were also analyzed by MPS.[Result]In normal walking,the PP of forefoot was 49% of body weight(BW)and of midfoot and heel was totally 51% of BW,but at pathologic state,the equilibrium of walking was dynamically disrapted inducing a pathologic changes of foot bearing.[Conclusion]Self-developed MPS for measuring PP is help for dynamic analysis of normal PP and is valuable to recognize the pathologic distribution of PP in pathological state and to provide a guide for treatment.

A Preliminary Study on Non-invasive Measurement of Intra-abdominal Pressure / 航天医学与医学工程

Objective To present a new method and design of an instrument for measuring intra-abdominal pressure (IAP) non-invasively. Method A pressure sensor (YH-4) and a displacement sensor (sliding rheostat) were assembled into a probe so that they work in a linear mode. When this assembled instrument probe acts on the abdominal wall of a subject, a pressure as called the external abdominal pressure (EAP), and a corresponding displacement were detected. A relationship was established mathematically between the IAP measured by non-invasive and invasive method, and IAP was calculated by EAP measurement indirectly non-invasively. Result The method was testified by animal experiment in rabbits. And the preliminary results indicated that linear relation between EAP and IAP was obtained. Conclusion Feasibility of the new method is validated by animal experiment. It provides scientific evidence for further clinical experiment.

Progress of the detection technology of the respiratory signal / 医疗卫生装备

Respiration is an important physiological process. The detection of th e respiratory signal is a main part of the modern wardship. This paper discusses the detection methods of the respiratory signal and compares their performances and application ranges.

Development of New Apparatus for Oriental Pulse Diagnosis / 日本東洋医学雑誌

The authors developed an innovative apparatus for analyzing pulse waves which uses a new type of pulse sensor. Based on the principles of Oriental medicine, this pulse wave machine takes measurements from the radial artery to determine the subject's state of health. Three sensors were used in place of the fingers to assess changes in the pulse wave pattern induced by reducing pressure in a cuff. A cuff with sliding components proved to be the most suitable in that it was less likely to be affected by the subject's movements. Using this type of cuff, the authors were able to observe the pulse-wave amplitude as cuff pressure was reduced after the blood flow had been stopped. The signal in each channel changed according to the degree of pressure reduction, and a characteristic pulse wave pattern was produced. This pattern enabled the authors to observe how the pulse behaved under each sensor and how the pulse wave changed. The authors were also able to observe and measure the condition velocity as the artery opened as well as assess the condition of the palmer arterial arch.