桡动脉触力传感器和脉象仪动态性能检测装置的研制

依据桡动脉触力传感器动态性能检测和中医脉图波形的技术要求,提出了一种既能产生具有标准信号源的锯齿波、正弦波和方波,用于检测桡动脉触力传感器性能,又能产生仿真中医脉图波形输出,用于检测脉象仪动态性能的检测装置。该装置覆盖了桡动脉脉搏波触力传感器、脉象诊断仪的静态和动态性能检测的全部要求,从而改变了以往用阶跃信号进行传感器频响计算的局面。     

Cost-effectiveness analysis and innovation

While cost-effectiveness (CE) analysis has provided a guide to allocating often scarce resources spent on medical technologies, less emphasis has been placed on the effect of such criteria on the behavior of innovators who make health care technologies available in the first place. A better understanding of the link between innovation and cost-effectiveness analysis is particularly important given the large role of technological change in the growth in health care spending and the growing interest of explicit use of CE thresholds in leading technology adoption in several Westernized countries. We analyze CE analysis in a standard market context, and stress that a technology's cost-effectiveness is closely related to the consumer surplus it generates. Improved CE therefore often clashes with interventions to stimulate producer surplus, such as patents. We derive the inconsistency between technology adoption based on CE analysis and economic efficiency. Indeed, static efficiency, dynamic efficiency, and improved patient health may all be induced by the cost-effectiveness of the technology being at its worst level. As producer appropriation of the social surplus of an innovation is central to the dynamic efficiency that should guide CE adoption criteria, we exemplify how appropriation can be inferred from existing CE estimates. For an illustrative sample of technologies considered, we find that the median technology has an appropriation of about 15%. To the extent that such incentives are deemed either too low or too high compared to dynamically efficient levels, CE thresholds may be appropriately raised or lowered to improve dynamic efficiency.     

Predicting instrument detection efficiency when scanning point and small area radiation sources

Accurate quantification of radionuclides detected during a scanning survey relies on an appropriately determined scan efficiency calibration factor (SECF). Traditionally, instrument efficiency is determined with a stationary instrument and a fixed source geometry. However, as is often the case, the instrument is used in a scanning mode where the source to instrument geometry is dynamic during the observation interval. Procedures were developed to determine the SECF for a point source ("hot particle") and a 10 x 10 cm source passing under the centerline of a 12.7 x 7.62 cm NaI(Tl) detector. The procedures were first tested to determine the SECF from a series of static point source measurements using Monte Carlo N-Particle code. These point static efficiency values were then used to predict the SECF for scan speeds ranging from 10 cm s(-1) to 80 cm s(-1) with a simulated instrument set to collect integrated counts for 1 s. The Monte Carlo N-Particle code was then used to directly determine the SECF by simulating a scan of a point source and 10 x 10 cm area source for scan speeds ranging from 10 cm s(-1) to 80 cm s(-1). Comparison with Monte Carlo N-Particle scan simulation showed the accuracy of the SECF prediction procedures to be within +/-5% for both point and area sources. Experimental results further showed the procedures developed to predict the actual SECF for a point and 10 x 10 cm source to be accurate to within +/-10%. Besides the obvious application to determine an SECF for a given scan speed, this method can be used to determine the maximum detector or source velocity for a desired minimum detectable activity. These procedures are effective and can likely be extended to determine an instrument specific SECF for a range of source sizes, scan speeds, and instrument observation intervals.     

Which valued‐based price when patients are heterogeneous?

We use a simple model to study the static and dynamic efficiency of alternative regulation regimes for the reimbursement of medical innovations when responses to a new treatment (effectiveness) are heterogeneous across the eligible population. When the rational behavior of profit‐maximizing firms is taken into account, only average value‐based prices can ensure both static and dynamic efficiency, but they imply higher expenditure and lower consumer surplus. Ignoring dynamic efficiency, if patients' responses are sufficiently homogeneous, marginal value‐based prices may dominate from the payer's perspective. We also present a refinement of average value‐based prices that could reverse this result. Overall, the cost of ensuring static and dynamic efficiency is increasing in the degree of heterogeneity. A real‐world example is used to illustrate these results.     

Casting the screening net: separating big fish from little fish

Screening tests are a rapidly growing part of medical practice. If we are going to make the best use of resources, screening tests need to be considered in terms of effectiveness, efficiency and equity. We present a framework as a way to think about screening programmes. The framework expands on existing literature that recognizes two categories of screening: universal and opportunistic. By adding the dimension of 'selectivity', we identify four categories of screening: active non-selective (universal or mass screening), active selective, opportunistic non-selective and opportunistic selective. We illustrate the framework by categorizing screening recommendations for high serum cholesterol levels. We conclude there is no one ideal strategy for screening that simultaneously satisfies criteria of effectiveness, efficiency and equity. However, our framework allows a systematic consideration and balancing of these objectives in the development and assessment of screening programs. In this way, it may assist decision-makers by making this trade-off more explicit.     

Is there a trade-off between longevity and quality of life in Grossman's pure investment model?

The question is posed whether an individual maximizes lifetime or trades off longevity for quality of life in Grossman's pure investment (PI)-model. It is shown that the answer critically hinges on the assumed production function for healthy time. If the production function for healthy time produces a trade-off between life-span and quality of life, one has to solve a sequence of fixed time problems. The one offering maximal intertemporal utility determines optimal longevity. Comparative static results of optimal longevity for a simplified version of the PI-model are derived. The obtained results predict that higher initial endowments of wealth and health, a rise in the wage rate, or improvements in the technology of producing healthy time, all increase the optimal length of life. On the other hand, optimal longevity is decreasing in the depreciation and interest rate. From a technical point of view, the paper illustrates that a discrete time equivalent to the transversality condition for optimal longevity employed in continuous optimal control models does not exist.     

The regulation of health care providers' payments when horizontal and vertical differentiation matter

This paper analyzes the regulation of payment schemes for health care providers competing in both quality and product differentiation of their services. The regulator uses two instruments: a prospective payment per patient and a cost reimbursement rate. When the regulator can only use a prospective payment, the optimal price involves a trade-off between the level of quality provision and the level of horizontal differentiation. If this pure prospective payment leads to underprovision of quality and overdifferentiation, a mixed reimbursement scheme allows the regulator to improve the allocation efficiency. This is true for a relatively low level of patients' transportation costs. We also show that if the regulator cannot commit to the level of the cost reimbursement rate, the resulting allocation can dominate the one with full commitment. This occurs when the transportation cost is low or high enough, and the full commitment solution either implies full or zero cost reimbursement.     

Cost-Effectiveness and Dynamic Efficiency: Does the Solution Lie Within?

The majority of the current systems spread across the world require the value of pharmaceuticals to be demonstrated with an acceptable degree of certainty before a technology is funded. Often involving the notion of cost-effectiveness, one of the key characteristics of such assessments tends to be the consideration of efficiency as a static outcome; with a strong emphasis on current health gains but a disregard for the impact of decision making on the potential health value over time. In this article, we argue that current systems using cost-effectiveness thresholds may provide an incomplete indicator of value. We defend the idea that funding decisions should also be informed by dynamic efficiency considerations and reflect both the current and the future value of achieving a certain level of effectiveness in a specific disease area. We further lay down the foundations for the implementation of such a value assessment framework.     

三维动态仿真技术在DNA合成仪研制中的应用

目的:为了提高多通道高通量DNA合成仪的设计开发效率,将三维动态仿真技术引入到研制过程,分析其应用方法和应用价值。方法:以DNA合成仪的关键部件合成舱为例,分析了三维计算机辅助设计流程,在三维实体建模基础上研究了动态优化分析和动态装配仿真方法,探讨三维动态仿真技术在DNA合成仪中的应用方法,展望动态仿真技术的潜在应用价值。结果:实现了DNA合成仪合成舱的动态优化分析和动态装配仿真,完善了三维计算机辅助设计技术的设计流程,为DNA合成仪等仪器设备的动态仿真提供参考方法。结论:应用动态仿真技术可提高DNA合成仪的研制效率,对设计方案制定及装配优化、设计优化、制造优化、成本优化有重要意义。     

Floor/shoe slip resistance measurement.

A variety of slip measurement devices exist that provide estimates of both static and dynamic coefficient-of-friction (COF) values between one's shoes and the floor. Unfortunately, different shoe sole/heel materials, floor conditions, and contaminants will affect the tests in ways that result in widely varying COF estimates. This paper reviews the basic physics of such tests and describes a set of experiments to determine the static and dynamic COF values under operating conditions known to exist in different jobs. The results define a set of conditions wherein low (hazardous) COF values would exist (e.g., hard Neolite shoe material in contact with a wet, smooth walking surface). The results also question the use of light-load testing devices and static and slow speed reference COF values in the literature.     

Establishing health state valuations for disease specific states: an example from heart disease

This study considers the feasibility of defining a QALY from disease-specific data using the New York Heart Association (NYHA) classification of heart failure. The study derives health state values for the four different NYHA classifications of disease progression using the time trade-off (TTO) instrument associated with the five dimensional (EQ-5D) health state valuation method. Consistent mappings between the disease classification and the chosen QALY instrument are found. With this being the case, the assumption of constant proportionality, which is necessary to define the QALY as an acceptable measure of health related preferences, is considered. It is found that constant proportionality does not hold across the more severe health states, thus questioning the use of QALYs as representing cardinal preference structures.     

Value‐Based Differential Pricing: Efficient Prices for Drugs in a Global Context

This paper analyzes pharmaceutical pricing between and within countries to achieve second‐best static and dynamic efficiency. We distinguish countries with and without universal insurance, because insurance undermines patients' price sensitivity, potentially leading to prices above second‐best efficient levels. In countries with universal insurance, if each payer unilaterally sets an incremental cost‐effectiveness ratio (ICER) threshold based on its citizens' willingness‐to‐pay for health; manufacturers price to that ICER threshold; and payers limit reimbursement to patients for whom a drug is cost‐effective at that price and ICER, then the resulting price levels and use within each country and price differentials across countries are roughly consistent with second‐best static and dynamic efficiency. These value‐based prices are expected to differ cross‐nationally with per capita income and be broadly consistent with Ramsey optimal prices. Countries without comprehensive insurance avoid its distorting effects on prices but also lack financial protection and affordability for the poor. Improving pricing efficiency in these self‐pay countries includes improving regulation and consumer information about product quality and enabling firms to price discriminate within and between countries. © 2013 The Authors. Health Economics published by John Wiley & Sons Ltd.     

Dynamic versus static models in cost-effectiveness analyses of anti-viral drug therapy to mitigate an influenza pandemic

Conventional (static) models used in health economics implicitly assume that the probability of disease exposure is constant over time and unaffected by interventions. For transmissible infectious diseases this is not realistic and another class of models is required, so-called dynamic models. This study aims to examine the differences between one dynamic and one static model, estimating the effects of therapeutic treatment with antiviral (AV) drugs during an influenza pandemic in the Netherlands. Specifically, we focus on the sensitivity of the cost-effectiveness ratios to model choice, to the assumed drug coverage, and to the value of several epidemiological factors. Therapeutic use of AV-drugs is cost-effective compared with non-intervention, irrespective of which model approach is chosen. The findings further show that: (1) the cost-effectiveness ratio according to the static model is insensitive to the size of a pandemic, whereas the ratio according to the dynamic model increases with the size of a pandemic; (2) according to the dynamic model, the cost per infection and the life-years gained per treatment are not constant but depend on the proportion of cases that are treated; and (3) the age-specific clinical attack rates affect the sensitivity of cost-effectiveness ratio to model choice. Copyright © 2009 John Wiley & Sons, Ltd.     

Quality of Life and Asthma Symptom Control: Room for Improvement in Care and Measurement

BackgroundThe recent Global Initiative for Asthma management strategy recommends achieving symptom control and minimizing the future risk of poor outcomes as priorities for asthma management.ObjectiveThe objective was to quantify the association between symptom control and health-related quality of life in asthma.MethodsIn a prospectively recruited random sample of adults with asthma, we ascertained symptom control and measured health-related quality of life using a generic (EuroQol five-dimensional questionnaire [EQ-5D]) and a disease-specific (Asthma Quality of Life Questionnaire) instrument, to estimate EQ-5D and five-dimensional Asthma Quality of Life Questionnaire (AQL-5D) utilities, respectively. We measured the adjusted difference in utilities across symptom control levels and calculated the loss of predictive efficiency due to aggregating multiple symptoms into one symptom control variable.ResultsThe final sample included 958 observations from 494 individuals (mean age at baseline 52.2 ± 14.5 years; 67.0% women). Asthma was symptomatically controlled, partially controlled, and uncontrolled in 269 (28.1%), 367 (38.3%), and 322 (33.6%) observations, respectively. A person with symptomatically uncontrolled asthma would gain 0.0512 (95% CI 0.0339–0.0686) in EQ-5D or 0.0802 (95% CI 0.0693–0.0910) in AQL-5D utilities by achieving symptom control. The loss of predictive efficiency was 55.4% and 27.6% for EQ-5D and AQL-5D utilities, respectively.ConclusionsAsthma symptom control status corresponds well with both generic and disease-specific quality-of-life measures. The trade-off, however, between ease of use and predictive power should be reconsidered in developing simplified measures of control. Our results have direct relevance in informing decision-analytic models of asthma and deducing the effect of interventions on quality of life through their impact on asthma control.     

Technology assessment in the Framingham Heart Study

To assess the role of observational data bases in technology assessment, we examined 26 articles from the Framingham Heart Study that evaluated a technology, therapy, or predictive instrument. These assessments were grouped into four categories: (a) the study of a technology voluntarily in use by the cohort, (b) the application of an external technology to members of the cohort, (c) the use of the Framingham results to evaluate an unrelated assessment, and (d) the use of the results to validate predictive instruments from other studies. Factors that contribute to the ability of the study to assess voluntary and external technologies include long-term follow-up, a stable cohort, and storage of such nonnumeric data as cardiograms and blood samples. Framingham results have been used to determine outcome measures in later studies. Although the Framingham Study was not designed to assess a technology, we found that large-scale, observational data bases can and do contribute to technology assessment.     

Assessing the gain in diagnostic performance when combining two diagnostic tests

Combining dichotomous (or dichotomized) results of two diagnostic tests will result in a trade-off in sensitivity and specificity of the combined test relative to the component tests. Because of this inherent trade-off, likelihood ratios provide a clinically relevant means of comparing the combined test with one of its components. The likelihood ratios depend on both sensitivity and specificity and hence take into account the trade-off between them. A graphical approach is used to assess whether the combined test is superior to a component test, or vice versa. Asymptotic standard errors are derived for comparing likelihood ratios when a paired study design is used. The trade-off in the expected number of additional true positive and false positive results (or true negative and false negative results) is used as the basis for deciding whether to use tests in combination when neither the combined nor a component test shows superior test performance based on their likelihood ratios. These methods are illustrated with an example that considers the combined use of Pap and HPV testing.     

预防电对人体的损害——对人体阻抗的认识

随着医学现代化的发展，医用电子仪器不仅大量用于人体外部，而且已深入到人体内部。伴随而来的是由于人们使用不当，常发生电击危险。     

Variation in the apparent importance of health-related problems with the instrument used to measure patient welfare

Aims

This paper investigates the distributional implications for eight population groups of using six different instruments to measure wellbeing and to prioritise access to health services. Specifically, it examines the importance of different physical and psycho-social problems for the scores obtained using each instrument and whether scores differ because of differences in the concept measured by the instrument or because of the instrument’s construction.

Methods

Patients with seven chronic conditions and a sample of the ‘healthy’ public were administered six instruments: two utility instruments; two self-rating scales; a subjective wellbeing instrument and the ICECAP measure of capability. Scores were regressed upon the subscales of the SF-36 and the AQoL-8D. Each instrument’s ‘problem mix’ was measured by the numerical importance of the subscales for the instrument’s score and compared with the problem mix of patients constructed from all of the instruments.

Results

The apparent importance of different problems varied significantly with the instrument used to assess welfare but not with the chronic conditions. The correspondence between an instrument’s problem mix and the patients’ problem mix was highly variable.

Conclusion

Different instruments give prominence to different physical and psycho-social problems and consequently favour different groups of patients. Budgetary decisions which appear to be based on efficiency criteria such as the cost per quality-adjusted life year (QALY) conceal distributive effects attributable to the instrument used in the analysis. The effects are additional to the ethical questions considered in making an equity–efficiency trade-off as they arise from the measurement of efficiency.

     

Estimating a Preference-Based Index for an Eight-Dimensional Health State Classification System for Multiple Sclerosis

BackgroundCondition-specific measures are frequently used to assess the health-related quality of life of people with multiple sclerosis (MS). Such measures are unsuitable for use in economic evaluations that require estimates of cost per quality-adjusted life-year because they are not based on preferences.ObjectivesTo report the estimation of a preference-based single index for an eight-dimensional instrument for MS, the Multiple Sclerosis Impact Scale – Eight Dimensions (MSIS-8D), derived from an MS-specific measure of health-related quality of life, the 29-item Multiple Sclerosis Impact Scale (MSIS-29).MethodsWe elicited preferences for a sample of MSIS-8D states (n = 169) from a sample (n = 1702) of the UK general population. Preferences were elicited using the time trade-off technique via an Internet-based survey. We fitted regression models to these data to estimate values for all health states described by the MSIS-8D. Estimated values were assessed against MSIS-29 scores and values derived from generic preference-based measures in a large, representative sample of people with MS.ResultsParticipants reported that the time trade-off questions were easy to understand. Observed health state values ranged from 0.08 to 0.89. The best-performing model was a main effects, random effects model (mean absolute error = 0.04). Validation analyses support the performance of the MSIS-8D index: it correlated more strongly than did generic measures with MSIS-29 scores, and it discriminated effectively between subgroups of people with MS.ConclusionsThe MSIS-8D enables health state values to be estimated from the MSIS-29, adding to the methods available to assess health outcomes and to estimate quality-adjusted life-years for MS for use in health technology assessment and decision-making contexts.     

肥胖和性别对8~10岁儿童静动态平衡能力的影响

  目的  探讨不同性别肥胖儿童静动态平衡能力特点, 为肥胖儿童运动损伤的预防以及运动选材提供理论依据。  方法  通过单腿前跳法与年龄分层抽样法, 从合肥市经开区5所小学选取100名8~10岁肥胖儿童及100名正常体重儿童为研究对象, 每组儿童男、女比例均为1∶1。采用IIM-BAL-100型静态平衡测试仪分别测试闭眼双足和睁眼单足站立状态下受试者各平衡指标的值, 采用Balance-check动态平衡测试仪测试睁眼双足站立状态下的动态平衡能力。使用双因素方差分析检验肥胖和性别对静动态平衡能力的影响。  结果  在静态平衡能力方面, 当闭眼双足站立时, 所有静态平衡指标值在肥胖、性别以及两因素交互作用间的差异均无统计学意义(F值分别为2.33, 0.42, 0.76, P值均>0.05);当睁眼单足站立时, 各静态平衡指标值在是否肥胖和性别间的差异均有统计学意义(F值分别为2.72, 3.07, P值均＜0.05)。在动态平衡能力方面, 所有动态平衡指标值在是否肥胖间的差异有统计学意义(F=43.67, P＜0.01)。  结论  8~10岁肥胖儿童的单足静态平衡能力和动态平衡能力弱于正常体重儿童; 8~10岁男童的单足静态平衡能力弱于女童。