[Research on Rapid Detection Technology for Quality Control of Emergency Ventilator].

OBJECTIVE: In order to grasp the quality status of the first-aid ventilator in pre-hospital and field environment in time, the quality control and detection items of invasive ventilator were optimized to form a rapid detection operation process of first-aid ventilator and ensure the safety of patient treatment. METHODS: Based on the quality control detection data of invasive ventilator in hospital in recent years, methods such as narrowing the range of qualified criteria and analyzing confidence interval were adopted to extract indicators prone to deviation and verify their correlation with similar indicators, so as to form an optimized rapid detection portfolio. RESULTS: Compared with the original quality control detection procedures, the detection indicators of the rapid detection procedures were reduced from 5 categories of 24 indicators to 3 categories of 7 indicators. The detection time was shortened by 56.1% and the coincidence rate of the detection results was 100% after the actual measurement and verification. CONCLUSIONS: Under the premise of ensuring the testing quality, the operating procedure for rapid detection of emergency ventilator can greatly reduce the detection time, and realize the rapid and high frequency quality control detection, so as to ensure the quality and safety of the equipment.

[Analysis of Factors on Clinical Application of Vehicle CT Shelter].

To assure the clinical quality and requirement of CT shelter used in field environment, the factors related with the practical application were studied. The evaluation indicators of CT equipment were investigated. Based on the technical modification of vehicle shelter CT, the scanning conditions of shelter CT were analyzed. Moreover, the comparative study was done between shelter CT and common CT in hospitals. In result, in order to meet maneuverability application in the field, vehicle shelter CT was restrictive by the field conditions, traffic impacts and running requirement. The application of vehicle shelter CT was affected by the factors, such as mechanical stabilization, moving precision, power fluctuations and variations of temperature and humidity, etc. The results were helpful to improve the clinical quality of vehicle shelter CT and made a base for the quality control study in the future.

[Analysis of specialized management and common use of emergency equipment in hospital].

To improve the usage rate and quality of emergency equipment in the hospital, the emergency equipment management was studied. The specialized management and common use of emergency equipment in a hospital was analysed with statistical methods. The usage rate, economic effectiveness and management quality of the equipment were evaluated. Based on the practical experience, the superiorities of the specialized management and common use of emergency equipment in hospitals were summarized, and the inferior positions and their improvement approaches were proposed. As a result, the hospital resource allocation was optimized and the equipment management level was improved by using the specialized management and common use of emergency equipment in the hospital.

[Comparison of three dynamic algorithms of electrical impedance tomography based on simulation study].

Three algorithms of electrical impedance tomography (EIT) are studied in this paper. The image resolution, anti-noise property and computation rapidity of the reconstruction algorithms are compared. As a result, it shows that back-projection algorithm has good anti-noise property, that NOSER algorithm generates images with good resolution, and that sensitivity matrix algorithm has moderate property.

[Ethic review on clinical experiments of medical devices in medical institutions].

Clinical experiments are always used to evaluate the safety and validity of medical devices. The experiments have two types of clinical trying and testing. Ethic review must be done by the ethics committee of the medical department with the qualification of clinical research, and the approval must be made before the experiments. In order to ensure the safety and validity of clinical experiments of medical devices in medical institutions, the contents, process and approval criterions of the ethic review were analyzed and discussed.

Application of electrical impedance tomography for continuous monitoring of retroperitoneal bleeding after blunt trauma.

Retroperitoneal bleeding is commonly associated with blunt trauma to the abdomen. Current medical tools cannot be used for continuous monitoring of the bleeding. In the study, electrical impedance tomography (EIT) was applied to monitoring the retroperitoneal bleeding of an animal model. Six healthy swine were used. The process of retroperitoneal bleeding was simulated by the continuous injection of anticoagulated blood. For each subject, total blood of 200 mL or more was injected within different time periods ranging from tens of minutes to two hours. The bleeding was detected and monitored continuously by EIT system with 16 electrodes at a rate of one image per second. EIT images were reconstructed by dynamic back-projection algorithm. Mean resistivity value (MRV) of the bleeding region in EIT images was calculated and plotted over time. We found that impedance changes caused by the bleeding could be revealed by EIT images and MRV curves. MRV curve varied approximately linearly with the quantity of blood injected using regression analysis (R (2) = 0.90 to 0.99, p < 0.05). In total, 20 mL of blood volume changes could be identified by EIT. The progression of the retroperitoneal bleeding can be monitored by EIT in the proposed animal model. It suggests EIT is potential as a useful tool for continuous monitoring of retroperitoneal bleeding after blunt trauma.

[A preliminary study of piglet intraperitoneal bleeding model and electrical impedance tomography monitoring].

Piglets having each a body weight of 20-30 kg and an abdominal perimeter like human's were used in the experiment. Being guided by ultrasound, we stabbed the piglet's abdomen, placed a catheter on the liver's lower margin, then injected the anticoagulated blood through the catheter by electrical infusion pump with constant speed respectively, and monitored the whole process by EIT. We observed the image change, using Ultrasound and CT to examine the area of blood injection after the end of monitoring,and we dissected to check the result of observations. The results reveal: (1) Ultrasound, CT and dissection are all able to find out a large amount of blood in piglet's abdominal cavity; (2) The pixel value of EIT target area decreases with the increase of blood, and the change in impedance image can be obviously observed. Therefore, this animal model is suitable for simulating intraperitoneal bleeding, and the speed of bleeding therein can be controlled. We can get a limpid image when EIT is used for monitoring the intraperitoneal bleeding simulated by this animal model.

A quantitative method based on total relative change for dynamic electrical impedance tomography.

We proposed a new method based on total relative change (TRC) from measured boundary voltages to quantify the volume changes of fluid during electrical impedance tomography (EIT) monitoring. The results showed that TRC linearly correlated with the volume of infused saline solution into a phantom, and the slope of TRC changes was approximately linear with the infusion speed. A inserted copper tube at different positions did not affect TRC significantly. The linear relationship between TRC and volume change indicates that TRC could be a good quantitative index for dynamic EIT.

Monitoring retroperitoneal bleeding model of piglets by electrical impedance tomography.

To investigate continuous monitoring capacity of electrical impedance tomography (EIT) for retroperitoneal bleeding, studies were carried out on six anesthetized piglet's bleeding model produced by injecting anticoagulated blood into renal region. For each subject, total blood of about 200 ml was injected within time periods ranging from tens of minutes to several hours. The simulated bleeding processes were detected and monitored by EIT system with sixteen electrodes at a rate of one image per second. EIT images were reconstructed by dynamic back-projection algorithm. The results showed that impedance changes caused by bleeding could be revealed by EIT images.

Pseudo-polar drive patterns for brain electrical impedance tomography.

Brain electrical impedance tomography (EIT) is a difficult task as brain tissues are enclosed by the skull of high resistance and cerebrospinal fluid (CSF) of low resistance, which makes internal resistivity information more difficult to extract. In order to seek a single source drive pattern that is more suitable for brain EIT, we built a more realistic experimental setting that simulates a head with the resistivity of the scalp, skull, CSF and brain, and compared the performance of adjacent, cross, polar and pseudo-polar drive patterns in terms of the boundary voltage dynamic range, independent measurement number, total boundary voltage changes and anti-noise performance based on it. The results demonstrate that the pseudo-polar drive pattern is optimal in all the aspects except for the dynamic range. The polar and cross drive patterns come next, and the adjacent drive pattern is the worst. Therefore, the pseudo-polar drive pattern should be chosen for brain EIT.

[A method of building the finite-element model with the contour line of human brain].

The contour line of human brain was simulated by the curve-fitting methods and then the inner area was discretized by advancing-front methods which was improved at last. The curve-fitting result was similar to the CT picture of the human brain and the discrete result of inner area could be completed quickly by improved advanced-front methods. A finite element model with the contour line of human brain was built primarily which will contribute to the next algorithm study of electrical impedance tomography in human brain.