基于WLAN的嵌入式输液滴速监护系统

针对目前输液监护系统的缺陷,提出基于嵌入式Linux实现输液滴速监护系统的模式,采用无线监护模式实时监护无线局域网内各个病房病人的输液状态。系统功能包括输液滴速检测、数据无线传输、滴速数据系统化处理、输液异常报警等。应用结果证明,该系统实施方便灵活,具有良好的可扩展性。     

Transfusion Cost Containment for Abdominal Surgery with Neural Networks

Typing and crossmatching blood is a significant cost for most hospitals, regardless of whether the blood is actually transfused. Many hospitals have implemented a Maximum Surgical Blood Order Schedule, MSBOS, to control over-ordering of blood units for surgery. The research presented in this article examines the use of neural networks for predicting the quantity of blood required by individual patients undergoing abdominal surgery (e.g. splenectomy). A comparison is made between the neural network predictions at a particular hospital versus the current MSBOS methodology for ordering surgical blood, by using the crossmatch to transfusion ratio. Results from the neural network transfusion predictions for the abdominal aortic aneurysm (AAA) surgery imply that neural networks can significantly improve the transfusion efficiency of hospitals. However, further examination of neural network capabilities for predicting the transfusion needs of patients undergoing other types of abdominal surgeries indicates that for operations other than the AAA, neural networks tend to under-predict the transfusion requirements of ten percent of the patients. Even if not used to limit over-ordering of blood for surgical transfusions, neural networks may be used as an intelligent decision support system to evaluate the current efficiency of hospital transfusion practices and to indicate beneficial changes to current MSBOS values.     

基于RTOS的输液监控系统的设计

基于目前国内绝大部分医疗机构点滴注射中存在的问题,介绍了一种应用于临床重力输液的输液速度自动监控系统的设计与实现方法,该系统基于MSP430F1232单片机和M430/OS嵌入式实时操作系统,采用上下位机模式并基于红外检测技术及模糊控制技术,实现了重力输液的本地及远程监控和管理,并可实现输液异常及输液结束报警;经实验证明,该系统具有检测精度高,输液速度调节快,操作方便的特点并且程序设计简化,具有较好的可读性及移植性.     

The Intelligent Ventilator (INVENT) project: the role of mathematical models in translating physiological knowledge into clinical practice

This dissertation has addressed the broad hypothesis as to whether building mathematical models is useful as a tool for translating physiological knowledge into clinical practice. In doing so it describes work on the INtelligent VENTilator project (INVENT), the goal of which is to build, evaluate and integrate into clinical practice, a model-based decision support system for control of mechanical ventilation. The dissertation describes the mathematical models included in INVENT, i.e. a model of pulmonary gas exchange focusing on oxygen transport, and a model of the acid-base status of blood, interstitial fluid and tissues. These models have been validated, and applied in two other systems: ALPE, a system for measuring pulmonary gas exchange and ARTY, a system for arterialisation of the acid-base and oxygen status of peripheral venous blood. The major contributions of this work are as follows. A mathematical model has been developed which can describe pulmonary gas exchange more accurately that current clinical techniques. This model is parsimonious in that it can describe pulmonary gas exchange from measurements easily available in the clinic, along with a readily automatable variation in F(I)O(2). This technique and model have been developed into a research and commercial tool (ALPE), and evaluated both in the clinical setting and when compared to the reference multiple inert gas elimination technique (MIGET). Mathematical models have been developed of the acid- base chemistry of blood, interstitial fluid and tissues, with these models formulated using a mass-action mass-balance approach. The model of blood has been validated against literature data describing the addition and removal of CO(2), strong acid or base, and haemoglobin; and the effects of oxygenation or deoxygenation. The model has also been validated in new studies, and shown to simulate accurately and precisely the mixing of blood samples at different PCO(2) and PO(2) levels. This model of acid-base chemistry of blood has been applied in the ARTY system. ARTY has been shown to accurately and precisely calculate arterial values of acid-base and oxygen status in patients residing in the ICU, and in those with chronic lung disease. The INtelligent VENTilator (INVENT) system has been developed for optimization of mechanical ventilator settings using physiological models and utility/penalty functions, separating physiological knowledge from clinical preference. The models can be tuned to the individual patient via parameter estimation, providing patient specific advice. The INVENT team has shown prospectively that the system provides advice on F(I)O(2) which is as good as clinical practice, and retrospectively that the system provides reasonable suggestions of tidal volume, respiratory frequency and F(I)O(2). In general, this dissertation has illustrated a further example of the role of modeling in describing and understanding complex systems. The dissertation has shown that when dealing with complexity the goal of the model must be in focus if a correct balance is to be maintained between system complexity and model parameterization. The original goal of the INVENT team, i.e. to build, evaluate and integrate a DSS for control of mechanical ventilation has not as yet been completed. However, the broader hypothesis that building models generates new and interesting questions has been successfully demonstrated. The ALPE model and system has been applied in intensive care, post operative care and cardiology and is currently being evaluated in new clinical domains. ARTY has been shown to have potential benefit in eliminating the need for painful arterial punctures, and may also be useful as a screening tool. These systems illustrate the benefits of investing in models as a mechanism for translating physiological knowledge to clinical practice.     

Type Directed Semantics for the Calculus of Looping Sequences

The calculus of looping sequences is a formalism for describing the evolution of biological systems by means of term rewriting rules. Here we enrich this calculus with a type discipline which preserves some biological properties deriving from the requirement of certain elements, and the repellency of others. In particular, the type system guarantees the soundness of the application of reduction rules with respect to the elements which are required (all requirements must be satisfied) and to the elements which are excluded (two elements which repel each other cannot occur in the same compartment). As an example, we model the possible interactions (and compatibility) of di?erent blood types with different antigens. The type system does not allow transfusion with incompatible blood types.     

心血管系统仿真模型的研究

为了深入研究心血管系统的生理机制以及探讨心血管系统的血流动力学参数与心血管疾病之间的关系,文中基于流体力学与电气网络的相关基础理论,根据人体心血管循环系统的解剖模型,提出一种基于集总参数的由体循环、肺循环和心脏组成的心血管系统仿真模型。重点分析了体循环子模型,并利用MATLAB 工具进行数学仿真,得出正常生理状况下的心血管参数,给出收缩压、舒张压、心室血容量等血流动力学参数。根据临床诊断参数调整体循环模型的各个参数,利用计算机仿真出高血压和心衰状况下的血流动力学仿真结果。仿真结果与临床的症状相一致,证明文中提出的模型具有一定的可行性。     

Evaluating the risk of healthcare failure modes using interval 2-tuple hybrid weighted distance measure

Failure mode and effects analysis (FMEA), as a usefulness and powerful risk assessment tool, has been widely utilized in different industries for improving the safety and reliability of systems. However, the conventional risk priority number (RPN) method shows some important weaknesses when applied in actual situations. Moreover, FMEA is a group decision behavior and FMEA team members tend to use different linguistic term sets to express their judgments because of their different backgrounds and preferences, some of which may be imprecise, uncertain and incomplete. In this paper, we propose a new risk priority model using interval 2-tuple hybrid weighted distance (ITHWD) measure to solve the problems and improve the performance of the traditional FMEA. The new model can not only handle the uncertainty and diversity of FMEA team members’ assessment information but also consider the subjective and objective weights of risk factors in the risk ranking process. The model has exact characteristic and can avoid information distortion and loss in the linguistic information processing. Finally, a case study of blood transfusion is provided to demonstrate the effectiveness and benefits of the proposed approach.     

病房红外自动呼叫系统的设计与实现

病人点滴打完时,若护士不能及时处理会导致病人静脉回血而给病人带来危险;为了解决这个问题,设计了一套红外自动呼叫系统;以单片机控制为核心,利用红外线传送信息及串行通信的方式实现病人点滴打完时能自动呼叫的功能,同时护士也可主动查询病人点滴情况;经过实验证明,该系统能及时地传送病人与护士之间的信息,具有很高的可靠性。     

Locational analysis for regionalization of Turkish Red Crescent blood services

After a series of earthquakes in 1999, Turkish Red Crescent (TRC) has engaged in a restructuring for all of its activities, including the blood services. Our study on the blood management system had been started as part of this initiative to restructure the blood services and improve both their effectiveness and efficiency. In the current system of TRC, not much consideration has been given to how the locational decisions affect the performance of blood centers, stations and mobile units. In recent years, however, there has been much discussion regarding the regionalization of the blood management system in Turkey. In this study, we develop several mathematical models to solve the location–allocation decision problems in regionalization of blood services. We report our computational results, obtained by using real data, for TRC blood services.     

Computer assisted diabetes care: a 6-year retrospective

Over the past 6 years we have designed a number of computer-based prototypes for the provision of therapeutic advice and the generation of glycaemic predictions in insulin-dependent (type 1) diabetic patients. In this paper we provide an overview of some of this work, and describe our experiences in trying to develop such methods for clinical use. We review, as an example, a model of the glucoregulatory system which has been developed for patient and medical staff education about type 1 diabetes mellitus, as well as possibly for therapeutic use. Using individualised parameter values the predictions of the model can be applied to generate 24-h simulations of patient blood glucose profiles. Previous preliminary retrospective validation work performed with this model has revealed a mean predictive accuracy for blood glucose simulations of approximately 2 mmol/l. Conceptual limitations of such modelling approaches are considered. We comment that such ‘mechanistic’ models may lack the necessary sophistication and flexibility to represent the complexity of the human glucoregulatory system and the challenges it has to face. Although such methodologies may therefore not be suitable for safe and effective application in routine clinical practice, we conclude that the evolution of such a system for demonstration/educational purposes could have widespread clinical utility as an interactive teaching tool.     

A formalized safety system for closed-loop anesthesia with pharmacokinetic and pharmacodynamic constraints

Closed-loop anesthesia drug delivery systems can reduce the effect of inter-patient variability, minimize variability in desired clinical effects, and ultimately improve patient safety. Feasibility of closed-loop anesthesia has been clinically evaluated in a number of studies. To obtain regulatory approval to use closed-loop anesthesia as a clinical device, patient safety must be demonstrated. Safety systems for closed-loop anesthesia have been proposed to limit anesthetic concentrations in the plasma and effect-site. Such safety systems minimize the risk of drug under/overdosing. Anesthetic drugs have serious side effects and can significantly reduce blood pressure, thereby jeopardizing patient safety. This paper discusses a safety system that includes safety constraints on blood pressure in addition to the plasma and effect-site concentrations. The proposed safety system is formalized using formal model verification techniques. The performance of closed-loop anesthesia in the presence of constraints on the plasma and effect-site concentrations as well as blood pressure is shown using simulation results. The effectiveness of the proposed safety system is also illustrated in simulation using a realistic clinical scenario. This paper shows that maintaining blood pressure within safety constraints increases the time for anesthesia induction, especially for patients whose blood pressure is more sensitive to anesthetics. For this population, clinical intervention such as administration of vasoactive drugs may be required to counter the effect of propofol on blood pressure during closed-loop anesthesia to achieve a safe yet sufficiently fast induction. This paper extends a previously published formalized safety system which guarantees that the plasma and effect-site concentrations remain within safety limits (Yousefi et al., 2017).     

Nonlinear robust blood–gas control by state linearisation for the cardiopulmonary bypass

A new feedback-control strategy is presented for the control of oxygen and carbon dioxide contents in the arterial blood during cardiopulmonary heart–lung support. In this highly nonlinear system incorporating process dependent time-delays, various uncertainties and time-varying parameters, the adjustment of blood gases has up to now been achieved manually by experienced perfusionist staff. This new control approach uses a state feedback-linearisation method with a Smith-like predictor and two external linear gain scheduled controllers. In a first stage the control was robustly designed and tuned with a complex and validated model of the blood–gas process. In a second stage the control was tested in simulations with the oxygenator model, extended by heart–lung machine dynamics. Both, oxygen and carbon dioxide controllers showed stability over the whole operating range and a good disturbance rejection to extracorporeal blood flow changes. The new control method is suggested to improve the patients’ safety and, as a side effect, to remove workload from the anaesthetist and the perfusion technician, so that they can focus on more critical tasks during the surgery.     

大输液中可见异物智能在线检测系统设计

设计了基于机器视觉的智能大输液异物在线检测系统,该系统可以实现灌装后大输液瓶中杂质的检测;研究了该检测系统的基本构成,工作原理以及一些关键图像处理技术;该检测系统采用特殊的硬件检测平台,让杂质与瓶身作相对运动,再利用精密的光学成像系统获取运动异物的序列图像,最后通过图像预处理、运动目标提取、运动目标分割和图像识别与判断这四个步骤完成对异物的检测;实验表明该系统可快速的检测出大输液溶液中所含的多种杂质.准确度高,实时性强。     

Knowledge discovery on RFM model using Bernoulli sequence

The objective of this paper is to introduce a comprehensive methodology to discover the knowledge for selecting targets for direct marketing from a database. This study expanded RFM model by including two parameters, time since first purchase and churn probability. Using Bernoulli sequence in probability theory, we derive out the formula that can estimate the probability that one customer will buy at the next time, and the expected value of the total number of times that the customer will buy in the future. This study also proposed the methodology to estimate the unknown parameters in the formula. This methodology leads to more efficient and accurate selection procedures than the existing ones. In the empirical part we examine a case study, blood transfusion service, to show that our methodology has greater predictive accuracy than traditional RFM approaches.     

Emergency department utilization can indicate early diagnosis of digestive tract cancers: A population-based study in Taiwan

Background and objective

Patients who visit emergency department (ED) may have symptoms of occult cancers.

Methods

We studied a random cohort of one million subjects from Taiwan National Health Insurance Research Database between 2000 and 2008 to evaluate the ED utilization of individuals who were subsequently diagnosed with digestive tract cancers. The case group was digestive tract cancer patients and the control group was traumatic fracture patients. We reviewed record of ED visits only from 4 to 15 months before the cancer diagnoses.

Results

There were 2635 and 6665 in the case and control groups respectively. Patients’ adjusted odds ratio with 95% confidence interval for the case group were 1.36 (1.06–1.74) for Abdominal ultrasound, 2.16 (1.61–2.90) pan-endoscopy, 1.72 (1.33–2.22) guaiac fecal-occult blood test, 1.42 (1.28–1.58) plain abdominal X-rays, 1.20 (1.09–1.32) SGOT, 1.27 (1.14–1.40) SGPT, 1.66 (1.41–1.95) total bilirubin, 2.41 (1.89–3.08) direct bilirubin, 1.21 (1.01–1.46) hemoglobin and 3.63 (2.66–4.94) blood transfusion, respectively. Blood transfusion in the ED was a significant predictor of the individual subsequently diagnosed with digestive tract cancer.

Conclusions

The health system could identify high risk patients early by real-time review of their ED utilization before the diagnosis of digestive tract cancers. We proposed a follow-up methodology for daily screening of patients with high risk of digestive tract cancer by informatics system in the ED.     

Evolutionary computation in the identification of risk factors. Case of TRALI

This paper presents the use of an evolutionary algorithm hybridized with the concepts of testor and typical testor in determining factors associated with transfusion related acute lung injury (TRALI). Although nowadays many cases of this syndrome remain ignored or misdiagnosed, this is the leading cause of morbidity and mortality related to transfusion in the United States.This research was conducted with data from 174 cases collected in the Centenary Hospital Miguel Hidalgo in the city of Aguascalientes, Mexico, in the period 2007 to 2010.The proposed algorithm works with information from the model known as “two hits”, in which the first hit is the original disease and the second corresponds to the blood transfusion. This algorithm was strengthened with mechanisms that let it do an efficient search in the whole solution space. In addition to the calculation of the informational weight, the algorithm also establishes the cutoff point that determines the variables that impact the most.From the results given by the algorithm and the cutoff proposed by the medical staff, a strategy for the treatment of patients that should be transfused was proposed.This study confirmed some of the risk factors previously reported in the literature, and also made an interesting discovery.     

Two-layered micropolar fluid flow through stenosed artery: Effect of peripheral layer thickness

An unsteady analysis of a two-layered blood flow through a flexible artery under stenotic conditions has been carried out in the present study where the flowing blood is represented by the two-fluid model, consisting of a core region of suspension of all erythrocytes assumed to be Eringen’s micropolar fluid and a plasma layer free from cells of any kind as a Newtonian fluid. The artery has been treated as an elastic (moving wall) cylindrical tube. The equations governing the unsteady flow mechanism subject to pulsatile pressure gradient, has been solved numerically using finite difference scheme by exploiting the appropriate physically realistic prescribed conditions. An extensive quantitative analysis has been performed through numerical computations in order to estimate the effect of different micropolar fluid parameters and the Reynolds number on the flow velocity, the flux, the resistive impedance and the wall shear stress together with their dependencies with time, the input pressure gradient and the severity of the stenosis. The graphical representations of these results do illustrate the flow characteristics of blood under stenotic conditions with proper scientific reasoning and hence validate the applicability of the model under consideration. Special emphasis has duly been made to compare the present theoretical results with the existing ones including experimental results and good agreement between them has been achieved both qualitatively and quantitatively.     

基于RS485总线的网络输液监控系统

设计构建了一个以PC机为上位机、以单片机为下位机、以RS485总线为基础的网络输液监控系统.在上位机中采用VC 可视化语言编程,创建可监视输液速度、设定速度、报警等多项功能的人机界面;下位机以8051单片机为核心,具有RS485总线转换接口、液滴检测、液滴速度控制、体温检测、脉搏检测、多种报警以及数据显示功能的监控终端系统.     

The implications of probability matching for clinician response to vital sign alarms: a theoretical study of alarm fatigue

Alarm fatigue has been recognised as a significant health technology safety risk. ‘Probability matching’, in which clinicians respond to the alarm at a rate identical to the perceived reliability of the alarm, has been postulated as a model to explain alarm fatigue. In this article, we quantitatively explore the implications of probability matching for systolic blood pressure alarms. We find that probability matching could have a profound effect on clinician response to the alarm, with a response rate of only 8.6% when the alarm threshold is 90 mm Hg and the optimal threshold for a systolic blood pressure alarm would only be 77 mm Hg. We use the mathematical framework to assess a mitigation strategy when clinicians have a limit to the capacity to respond. We find that a tiered alarm in which clinicians receive information on the severity of vital sign perturbation significantly improves the opportunity to rescue patients.

Practitioner Summary: Using a theoretical model, we predict that probability matching, a postulated model of clinician behaviour, can result in a profound decrease in clinician response to alarms for decreased blood pressure. A mitigating strategy is to create alarms that convey information on the degree of vital sign perturbation.     

Equivalent electrical network for performance characterization of piezoelectric peristaltic micropump

Utilizing an electronic–hydraulic analogy, this study develops an equivalent electrical network of a piezoelectric peristaltic micropump which has not been modeled the whole system operation completely by computational fluid dynamics (CFD) or equivalent electrical network so far due to its excessive complicated structure. The validity of the proposed model is verified by comparing the simulation results obtained using the SPICE (simulation program with integrated circuit emphasis) software package for flow rate spectrum and its maximum state of a typical micropump with the experimental observations for two working fluids, namely DI water and blood. The simulation results predict a maximum flow rate frequency and flow rate of 280 Hz and 43.23 μL/min, respectively, for water, and 210 Hz and 24.12 μL/min for blood. The corresponding experimental results are found to be 300 Hz and 41.58 μL/min for water and 250 Hz and 23.75 μL/min for blood. The relatively poorer agreement between the two sets of results when using blood as the working fluid is thought to be the result of the non-Newtonian nature of blood, which induces a more complex, non-linear flow behavior within the micropump. Having validated the proposed model, the equivalent network is used to perform a systematic analysis of the correlation between the principal micropump design parameters and operating conditions and the micropump performance. The results confirm the validity of the equivalent electrical network model as the first microfluidic modeling tool for optimizing the design of peristaltic micropumps and for predicting their performance.