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PubMed1988

Decision analysis: a tool for infection control.

The medical world would seem to be one of increasing technology and shrinking financial resources. New tests and therapies constantly appear on the market. Most have been examined for efficacy and side effects. The real question is: where does the new test or therapy fit in with all previous products? Decision analysis is a mathematical tool adapted to assess the relative cost-effectiveness of complex diagnostic and therapeutic strategies.

Bayes Theorem↗
PubMed1996

Hinge Distortion in Platinum(II) Dimers with a Pt(2)S(2) Ring. An ab Initio Molecular Orbital Study.

Ab initio calculations have been carried out for Pt(II) dimers with S(2)(-) and/or RS(-) bridging ligands in order to elucidate the factors governing the structural preference, planar or hinged, of these complexes. Calculations have been performed for systems which model all structurally characterized Pt(II) binuclear complexes. All possible determinants of the hinge angle have been taken into account in the ab initio calculations. These show that electronic rather than steric effects govern the geometry of the central Pt(2)S(2) ring. Only one minimum of energy has been found for each complex, but the energetic cost of the hinge motion is low. Complexes with two S(2)(-), or with one S(2)(-) and one RS(-), bridging ligands are hinged; the decrease of the through-ring antibonding interaction between the in-plane sulfur p orbitals with folding appears to be the determinant for hinging. Complexes with two RS(-) bridging ligands can be planar or hinged depending on the relative orientation, syn or anti, of the R groups, on the nature, L(4) or L(2)L(2)', of the terminal ligands, and in the latter case on their disposition, cis or trans. However, the aromatic or aliphatic nature of bridging thiolates does not influence the geometry of the Pt(2)S(2) ring significantly. Conclusions drawn from platinum dimers can be extended to the palladium analogs.

Journal Article↗
PubMed2002

First-order system least squares for elastohydrodynamics with application to flow in compliant blood vessels.

Mathematical modeling of compliant blood vessels generally involves the Navier-Stokes equations on the evolving fluid domain and constitutive structural equations on the tissue domain. Coupling these systems while accounting for the changing shape of the fluid domain is a major challenge in numerical simulation. Many techniques have been developed to model compliant vessels, but all suffer from disproportionate increase in computational cost as problem complexity increases (i.e., larger domains, more dimensions, and more variables.). Even the best standard methods result in computational cost that typically grows quadratically with the degrees of freedom. Using a least-squares formulation of the problem, elliptic grid generation for the changing fluid domain, and an algebraic multigrid solver for the linear system can overcome many shortcomings of standard techniques. Most notably, the computational cost of solving the problem increases linearly with the degrees of freedom and the associated functional provides an a posteriori error measurement. Least squares represents a systematic approach for formulating the original problem so that the numerical process becomes straightforward and optimal, and it avoids restrictions that often limit other methods. Results are presented for a two-dimensional test problem consisting of a Newtonian fluid with properties of blood in a linear-elastic vessel with properties of smooth muscle.

Computer Simulation↗
PubMed2003

Patient simulation for training basic and advanced clinical skills.

INTRODUCTION: Patient simulators are increasingly used in the education and training of healthcare professionals. This paper describes the history of human patient simulator development, the features of contemporary simulators, the acquisition of basic and advanced clinical skills using patient simulators, and the benefits, cost, limitations and effectiveness of this innovative learning modality. SIMULATOR DEVELOPMENT: The development of human patient simulators began in the late 1960s, and accelerated in the late 1980s and early 1990s. Several simulator systems are now professionally manufactured, commercially available, and used at hundreds of medical centres, universities and colleges in the USA and throughout the world. Contemporary patient simulators have many clinical features, and look and respond to interventions with ever-increasing degrees of realism because sophisticated physiological and pharmacological models automatically control many features. SIMULATOR USE IN MEDICAL EDUCATION: Simulators are used to teach basic skills, such as respiratory physiology and cardiovascular haemodynamics, and advanced clinical skills, e.g. management of difficult airways, tension pneumothorax, pulmonary embolism and shock. BENEFITS, COSTS AND LIMITATIONS: The simulation laboratory offers distinct educational advantages, especially for learning how to recognise and to treat rare, complex, clinical problems. Costs of simulator-based educational programmes include facility, equipment and personnel. Current limitations include clinical realism of the patient manikin and faculty development.

Clinical Competence↗
PubMed1996

[Economic aspects of sleep medicine].

According to its rules it is the task of the German Sleep Research Society (DGSM) to promote scientific research in the area of Sleep Medicine in Germany and to transform scientific results into clinical practice for the benefit of patient care. The international classification of sleep disorders (ICSD) distinguishes more than 80 different disorders which can be treated due to scientific progress which has been made over the last 50 years. The conversion of established scientific knowledge in the field of sleep medicine into an improved clinical management of patients should not be prevented by the lack of sufficiently equipped sleep units. The federal government has stated that, due to financial constraints, it would not consent to any measures which might lead to a budget increase, such as case oriented special payments for certain diseases. Thus, an adequate number of sleep units can only be provided by integrating these units into the budget of the respective hospitals and departments, paid by the local insurance companies, thus providing the necessary financial resources to the sleep units. Many services in the area of sleep medicine can be covered by the existing reimbursement system. In some cases, however, a definite diagnosis can only be made by the use of complete polysomnography (PSG). For a complete PSG the additional costs have been calculated by the DGSM to be 1195,-DM per 24 h. Sleep units dealing with both diagnostically and therapeutically complex cases such as patients requiring complex forms of nasal ventilation, depend on an increase in the reimbursement by the insurance companies to cover the expenses involved. For each sleep unit, a "case-mix" can be calculated which will include both complex and less complex cases. The costs using this case mix will be considerably lower than the cost for a complete PSG. Sleep units provide the basis for education and quality assessment which are necessary for competent patient management in the future. Adequate diagnostic and therapeutic facilities in sleep medicine provide the basis for patient care, contribute to improved health standards and, thus, reduce social costs of these frequent diseases.

Budgets↗
PubMed2006

Cost-effectiveness analysis for computer-aided surgical simulation in complex cranio-maxillofacial surgery.

PURPOSE: The purpose of this study is to assess the costs and benefits of computer-aided surgical simulation (CASS) and to compare it with the current surgical planning methods for complex cranio-maxillofacial (CMF) surgery. MATERIALS AND METHODS: The comparison of methods applies to all CMF surgeries where the patient's condition is severe enough to undergo a computed tomography scan and a stereolithographic model is necessary for the surgical planning process. The costs for each method can be divided into time and other costs. The time was estimated based on the authors' experience as well as on a survey of a small group of 6 experienced CMF surgeons in the United States. The other costs were estimated based on the authors' experience. RESULTS: CASS has lower costs in terms of surgeon time, patient time, and material costs. Specifically, total surgeon hours spent in planning are 5.25 hours compared with 9.75 for current standard methods. Material and scanning costs are Dollars 1,900 for CASS compared with about Dollars 3,510 for standard methods. Patient time for planning is reduced from 4.75 hours to 2.25 hours with CASS. The reduction in both time and other costs remains when the fixed fee costs of CASS are added to the variable costs. Amortized across the 600 patients per year (1,800 for the assumed 3-year life of the training and software), this adds only a few dollars and a fraction of an hour per surgery. Even in the case of a small clinic when the cost is amortized for 6 patients per year (18 patients for the assumed 3-year life of the training and software), the per surgery costs (9.65 hours and Dollars 2,456) will still favor CASS. CONCLUSION: Any great new design should consist of at least 2 of the 3 following features: faster, cheaper, and better outcome. This analysis demonstrates that CASS is faster and less costly than the current standard planning methods for complex CMF surgery. Previous studies have also shown that CASS results in better surgical outcomes. Thus, in all regards, CASS appears to be at least as good as the current methods of surgical planning.

Computer Simulation↗
PubMed2005

Innovation versus complexity: what is too much of a good thing?

What's the number of product or service offerings that would optimize both your revenues and your profits? For most firms, it's considerably lower than the number they offer today. The fact is, companies have strong incentives to be overly innovative in new product development. But continual launches of new products and line extensions add complexity throughout a company's operations, and as the costs of managing that complexity multiply, margins shrink. To maximize profit potential, a company needs to identify its innovation fulcrum, the point at which an additional offering destroys more value than it creates. The usual antidotes to complexity miss their mark because they treat the problem on the factory floor rather than at its source: in the product line. Mark Gottfredson and Keith Aspinall of Bain & Company present an approach that goes beyond the typical Six Sigma or lean-operations program to root out complexity hidden in the value chain. The first step is to ask, What would our company look like if it made and sold only a single product or service? In other words, you identify your company's equivalent of Henry Ford's one-size-fits-all Model T-for Starbucks, it might be a medium-size cup of coffee; for a bank, a simple checking account-and then determine the cost of producing that baseline offering. Next, you add variety back into the business system, product by product, and carefully forecast the resulting impact on sales as well as the cost implications across the value chain. When the analysis shows the costs beginning to overwhelm the added revenues, you've found your innovation fulcrum. By deconstructing their companies to a zero-complexity baseline, managers can break through organizational resistance and deeply entrenched ways of thinking to find the right balance between innovation and complexity.

Diffusion of Innovation↗
PubMed1993

[Is the Relative Complexity Index beta an accurate indicator of the cost of anesthesia?].

In order to assess the medical activity and the related costs, the French Ministry of Health has designed a relative value scale for medical procedures, the Relative Complexity Index (RCI). The RCI for anaesthesiology, called BETA, is the result of the combination of four subindexes: T for the type of anaesthesia, D for the duration, C for the related surgical procedure, and EG for the patient's status according to the ASA scale. The goal of this study has been to test whether the BETA index was actually an acceptable indicator of the direct cost of an anaesthetic. We have determined the cost of 248 procedures in a teaching hospital and achieved a statistical analysis of the relationship between costs, RCI and the various subindexes. The mean cost of an anaesthetic was 1,205 FF (SD = 1,325), 61.4% of which being for salaries. The cost of a general anaesthetic was 2.5 times higher than the cost of a local/regional anaesthesia procedure. Mean cost was around 700 FF for ENT, urology, gynaecology and obstetrics, 1,200 FF for orthopaedia and visceral surgery, and 5,130 FF for cardiac surgery (not including the equipment for extracorporeal circulation). A strong positive relation was found between the BETA and cost (r = 0.90, p < 10(-4)). The best predictive model of cost was log-linear, using only the duration, the type of anaesthetic and the related surgical procedure. The patient's status was not a significant factor, nevertheless in our sample, ASA 4 patients had a significantly higher cost than others (p = 0.0004, Mann & Whitney test).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Simulation of the evolution of genomic complexity.

A general evolutionary trend is the generation of organisms of increasing complexity, notwithstanding that reduction and simplification phenomena do occur in the evolutionary process. This paper proposes an evolutionary model incorporating the mechanisms of gene amplification and deletion. The evolutionary process leading to genomic complexity and the coexistence of simpler organisms with complicated ones were both simulated using the proposed model. The model was also used to investigate the influence of various factors on the evolution of complexity. The simulations indicated that the evolution of complexity is largely influenced by adaptation to complicated environments. Nevertheless, complex organisms require relatively more resources for survival and replication, which limits the on going tendency towards complexity. Moreover, the analysis showed that if the environment varies rapidly and the profit obtained from complexity is greater than the resources consumed, selection will tend to favor complexity. However, high living cost will tend to limit the trend of complexity and if the environment is relatively stable, reduction and simplification will become the dominant trends.

Animals↗
PubMed1996

The role of perspective in defining economic measures for the evaluation of medical technology.

Perspectives in an economic analysis of medical technology reflect who makes decisions about the use of or payment for medical resources. Commonly used perspectives include those of providers, insurers, the individual, and society. Perspective is a critical determinant of study design, affecting the time horizon, types of resources considered, and economic cost measures assigned to those resources. Individuals involved in technology assessment for either research or policy-making purposes should be aware of the complexities of defining costs from different perspectives.

Costs and Cost Analysis↗
PubMed2000

Mortality risks, costs, and decision making in transfusion medicine.

Traditional quality-adjusted life year (QALY) cost analysis is complex and assigns arbitrary dollar values to catastrophic outcomes such as death. Analysis of transfusion medicine technologies by an alternative approach that focuses on costs to avoid fatal outcomes might be a useful adjunct to QALY analysis for allocating limited financial resources. We estimated the cost per death averted for the following interventions: apheresis platelets vs random platelets, solvent detergent-treated plasma vs untreated plasma, and leukocyte-reduced vs unmodified transfusions in cardiac surgery. As a control, similar data were calculated for current donor viral testing. The estimated incremental costs per death avoided were as follows: single-donor apheresis platelets, $15 million; solvent detergent plasma, $17 million; leukocyte-reduced transfusions in cardiac surgery, $11,000; HIV-1 antibody testing, $22,000; and HIV-1 antigen testing, $3.9 million. The estimated number of deaths averted per year in our hospital were as follows: apheresis platelets, 0.1; solvent detergent plasma, 0.044; leukocyte-reduced transfusions, 14; HIV-1 antibody testing, 6.0; and HIV-1 antigen testing, 0.033. HIV-1 antibody testing and leukocyte-reduced transfusions in cardiac surgery are comparably cost-efficient means of averting mortality in patients receiving transfusions. Solvent detergent plasma and apheresis platelets are comparatively expensive approaches to reducing mortality from transfusion complications.

Blood Transfusion↗
PubMed1990

Untangling management structures.

Hospital executives looking for ways to cut costs are finding that complex hospital management structures contribute to higher healthcare costs and cumbersome decisionmaking. Several hospitals are trying to undo the damage, while folks in Washington are doing their part to speed the slimming process.

Cost Control↗
PubMedDate not supplied

Glyburide compared to insulin for the treatment of gestational diabetes mellitus: a cost analysis.

OBJECTIVE: To compare the costs associated with glyburide compared to insulin for the treatment of gestational diabetes unresponsive to dietary therapy. STUDY DESIGN: A cost model was designed. The model excluded costs that were identical for both treatment arms, such as the cost of monitoring glucose control. Insulin treatment costs included average wholesale drug costs, wholesale delivery costs (syringes, alcohol pads), and costs of office staff educating patients. Glyburide costs were based on average wholesale drug costs. Downstream costs of potential inpatient evaluation for hypoglycemia were included in the model. RESULTS: In our baseline model, glyburide was significantly less costly than insulin for the treatment of gestational diabetes. The average cost saving per patient based on wholesale drug costs and hospital costs was US$165.84. Actual retail drug savings and hospital charge savings are potentially considerably greater. The strongest determinant of cost savings was medication cost. The model was less sensitive to the one-time costs of inpatient treatment and patient education. CONCLUSION: Glyburide is less costly than insulin for the treatment of gestational diabetes. Cost models can be useful to physicians deciding between two equally efficacious medications, allowing them to incorporate information about their individual practice styles with a complex balance of cost implications.

Costs and Cost Analysis↗
PubMed2004

Hybrid simulation of cellular behavior.

MOTIVATION: To be valuable to biological or biomedical research, in silico methods must be scaled to complex pathways and large numbers of interacting molecular species. The correct method for performing such simulations, discrete event simulation by Monte Carlo generation, is computationally costly for large complex systems. Approximation of molecular behavior by continuous models fails to capture stochastic behavior that is essential to many biological phenomena. RESULTS: We present a novel approach to building hybrid simulations in which some processes are simulated discretely, while other processes are handled in a continuous simulation by differential equations. This approach preserves the stochastic behavior of cellular pathways, yet enables scaling to large populations of molecules. We present an algorithm for synchronizing data in a hybrid simulation and discuss the trade-offs in such simulation. We have implemented the hybrid simulation algorithm and have validated it by simulating the statistical behavior of the well-known lambda phage switch. Hybrid simulation provides a new method for exploring the sources and nature of stochastic behavior in cells.

Algorithms↗
PubMed2004

Internal filtration-enhanced hemodialysis is a cost-effective treatment in view of solute removal.

By modifying dialyzer module design, internal filtration (IF) within a dialyzer is enhanced to increase convective solute transport. Thus, it can be an alternative to hemodiafiltration with no requirement of substitution fluid or additional complex machines. Cost-effective analysis was conducted in three modes of therapy: high-flux hemodialysis, on-line hemodiafiltration and IF-enhanced hemodialysis. In IF-enhanced hemodialysis, cost-effectiveness of small solute removal is comparable with high-flux hemodialysis and that of beta(2)-microglobulin removal is the best. It is concluded that IF-enhanced hemodialysis is the most cost-effective therapy mode in comprehensive overall solute removal.

Cost-Benefit Analysis↗
PubMed2003

Cost effectiveness of HMG-CoA reductase inhibitors in the management of coronary artery disease: the problem of under-treatment.

HMG-CoA reductase inhibitors significantly reduce the risk of coronary artery disease (CAD) events and CAD-related mortality in patients with and without established CAD. Consequently, HMG-CoA reductase inhibitors have a central role within recommendations for lipid-modifying therapy. However, despite these guidelines, only one-third to one-half of eligible patients receive lipid-lowering therapy and as few as one-third of these patients achieve recommended target serum levels of low density lipoprotein-cholesterol. The underuse of HMG-CoA reductase inhibitors in eligible patients has important implications for mortality, morbidity and cost, given the enormous economic burden associated with CAD; direct healthcare costs, estimated at US $16-53 billion (2000 values) in the US and 1.6 billion pound (1996 values) in the UK alone, are largely driven by inpatient care. Hospitalization costs are reduced by treatment with HMG-CoA reductase inhibitors, particularly in high-risk groups such as patients with CAD and diabetes mellitus in whom net cost savings may be achieved. HMG-CoA reductase inhibitors are underused because of institutional factors and clinician and patient factors. Also, the vast number of patients eligible for treatment means that the use of HMG-CoA reductase inhibitors is undoubtedly limited by budgetary considerations. Secondary prevention in CAD using HMG-CoA reductase inhibitors is certainly cost effective. Primary prevention with HMG-CoA reductase inhibitors is also cost effective in many patients, depending upon CAD risk and drug dosage. As new, more powerful, HMG-CoA reductase inhibitors come to market, and the established HMG-CoA reductase inhibitors come off patent, the identification of the most cost-effective therapy becomes increasingly complex. Research in to the relative cost effectiveness of alternative HMG-CoA reductase inhibitors, taking full account of the institutional, clinician and patient barriers to uptake should be undertaken to identify the most appropriate role for the new therapies.

Coronary Artery Disease↗
PubMed1997

A pilot study of the cost of educating undergraduate medical students at Virginia Commonwealth University.

PURPOSE: To develop a model isolating the annual per-student cost of, and the fund sources for, educating undergraduate medical students at the Virginia Commonwealth University Medical College of Virginia School of Medicine. METHOD: For 1994-95, hours that faculty spent in direct scheduled contact with students and time that students spent in direct scheduled contact with faculty were inventoried. Student, faculty, and resident contact hours for clinical clerkships and electives were estimated. Faculty contact hours and average faculty workload profiles were used to compute the number of full-time-equivalent faculty positions required to deliver the undergraduate medical curriculum. Support staff and operating budget requirements were based on the number of required faculty, and actual salary averages were used to compute faculty and staff costs. Other institutional costs that indirectly support undergraduate medical education were estimated. Using faculty contact hours and actual cost data, fund sources that support undergraduate medical education were identified. RESULTS: Medical school faculty spent more than 89,000 scheduled hours teaching 674 undergraduate medical students. The faculty-student ratio was 1:3.35. Residents spent nearly 79,000 hours training undergraduate medical students. The total annual cost of undergraduate medical education was $69,992 per student. State funds contributed less than a third of the required financial resources; faculty clinical practice funds provided nearly half. CONCLUSION: Although there are inherent complexities, isolating the cost and fund sources of undergraduate medical education is an essential first step toward providing categorical funding. The model developed during the study provides a basis for assigning costs, allocating resources among instructional programs, and predicting incremental costs (or savings) and revenue requirements. The model may be of use to other medical schools contemplating new strategies for financing undergraduate medical education.

Costs and Cost Analysis↗
PubMed2005

Intellectual disability, challenging behaviour and cost in care accommodation: what are the links?

The paper examines the links between degree of intellectual disability, challenging behaviour, service utilisation and cost for a group of people with intellectual disabilities living in care accommodation in England. A cross-sectional survey was conducted of people with intellectual disabilities, identified via provider organisations, with supplementary collection of costs data. Multivariate analyses of cost variations were carried out for 930 adults with intellectual disabilities. There were strong, nonlinear, interdependent links between degree of intellectual disability, behaviour, service use and costs. Higher costs were associated with more severe intellectual disabilities and more challenging behaviour. Sector and scale of residence also influenced cost in quite complex ways. Access to and use of services by people with intellectual disabilities were not always appropriately linked to perceived or actual needs. Policy makers and local commissioning agencies need to explore the sources of cost variation between individuals, sectors and types of accommodation in order to achieve national policy objectives on quality, choice, independence and inclusion.

Adolescent↗