Force approach for the pseudopotential lattice Boltzmann method.

One attractive feature of the original pseudopotential method consists on its simplicity of adding a force dependent on a nearest-neighbor potential function. In order to improve the method, regarding thermodynamic consistency and control of surface tension, different approaches were developed in the literature, such as multirange interactions potential and modified forcing schemes. In this work, a strategy to combine these enhancements with an appropriate interaction force field using only nearest-neighbor interactions is devised, starting from the desired pressure tensor. The final step of our procedure is implementing this external force by using the classical Guo forcing scheme. Numerical tests regarding static and dynamic flow conditions were performed. Static tests showed that current procedure is suitable to control the surface tension and phase densities. Based on thermodynamic principles, it is devised a solution for phase densities in a droplet, which states explicitly dependence on the surface tension and interface curvature. A comparison with numerical results suggest a physical inconsistency in the pseudopotential method. This fact is not commonly discussed in the literature, since most of studies are limited to the Maxwell equal area rule. However, this inconsistency is shown to be dependent on the equation of state (EOS), and its effects can be mitigated by an appropriate choice of Carnahan-Starling EOS parameters. Also, a droplet oscillation test was performed, and the most divergent solution under certain flow conditions deviated 7.5% from the expected analytical result. At the end, a droplet impact test against a solid wall was performed to verify the method stability, and it was possible to reach stable simulation results with density ratio of almost 2400 and Reynolds number of Re=373. The observed results corroborate that the proposed method is able to replicate the desired macroscopic multiphase behavior.

[Home care for patients with ictus cerebri. An observational study in the metropolitan area of Milano]. / L'assistenza domiciliare ai pazienti colpiti da ictus cerebrale. Studio osservazionale nell'ambito della città di Milano.

Health care assessment is a very relevant process in health services organization. Despite home care appears to be a very important tool in health care delivery system, its impact has been only rarely evaluated in this country. The observational study we performed in the ASL Città di Milano on patients affected by ictus cerebri was aimed at addressing some questions in order to assess whether services can be delivered more cost effectively. We chose to look mainly at the effectiveness and cost of services for the people in need and their caregivers selected in two years time. The results are showed according to different patients' profiles and precocity of recruitment. Their analysis shows that further improvements can still be made in order to achieve a better tailored profile of delivery. Moreover it can be seen how the burden of costs still falls largely on families and caregivers. The study can be seen as premises for further analyses as well as a follow up intervention.

Cost-effectiveness analysis of invasive and noninvasive tests in high risk patients treated with amiodarone after acute myocardial infarction.

OBJECTIVES: We sought to evaluate 1) the cost-effectiveness of amiodarone therapy in postinfarction patients; and 2) the influence of alternative diagnostic strategies (noninvasive only vs. noninvasive and electrophysiologic testing) on survival benefit and cost-effectiveness ratio of amiodarone therapy. BACKGROUND: The cost-effectiveness of amiodarone therapy in postinfarction patients is still unknown, and no study has determined which diagnostic strategy should be used to maximize amiodarone survival benefit while improving its cost-effectiveness ratio. METHODS: We designed a postinfarction scenario wherein heart rate variability analysis on 24-h Holter monitoring was used as a screening test for 2-year amiodarone therapy in a cohort of survivors (mean age 57 years) of a recent myocardial infarction. Three different therapeutic strategies were compared: 1) no amiodarone; 2) amiodarone in patients with depressed heart rate variability; 3) amiodarone in patients with depressed heart rate variability and a positive programmed ventricular stimulation. Total variable costs and quality-adjusted life expectancy during a 20-year period were predicted with use of a Markov simulation model. Costs and charges were calculated with reference to an Italian and American hospital. RESULTS: Amiodarone therapy in patients with depressed heart rate variability and a positive programmed ventricular stimulation was dominated by a blend of the two alternatives. Compared with the no-treatment strategy, the incremental cost-effectiveness ratio of amiodarone therapy in patients with depressed heart rate variability was $10,633 and $39,422 per gained quality-adjusted life-year using Italian costs and American charges, respectively. CONCLUSIONS: Compared with a noninterventional option, amiodarone prescription in all patients with depressed heart rate variability seems to be a more appropriate approach than the alternative based on the combined use of heart rate variability and electrophysiologic study.

Economic evaluation of diagnostic follow-up after primary treatment for breast cancer. Results of the Working Group on Economic-Organizational Aspects of Follow-up.

BACKGROUND: This study examined costs associated with different 5-year follow-up regimens (intensive vs. minimum) in patients after primary breast cancer treatment. METHODS: Since the results of two randomised controlled trials showed a similar 5-year survival for asymptomatic patients followed with frequent diagnostic tests and patients followed with only routine clinical controls, the economic savings resulting from the systematic adoption of a minimum surveillance regimen were estimated for Italy. RESULTS: When considering only direct health care costs (i.e., excluding time and travel costs) and adopting a minimalist policy, the average per patient savings (5% yearly compound rate) were calculated at 3.7 million Italian lire for paying patients, 2.5 million Italian lire for patient reimbursement from private voluntary/integrative health insurance funds, and to range from 1.2 to 2.1 million Italian lire for payment to the National Health Service (NHS). Total follow-up savings for the patient cohort which had breast surgery in the last 5 years were estimated to range from 29 to 51 billion Italian lire for the NHS, 92 billion Italian lire for paying patients and 62 billion Italian lire for the health insurance funds. CONCLUSIONS: Alternative use of these savings were discussed with reference to breast cancer screening programs.

Economic evaluation of lenograstim (glycosylated rHuG-CSF) in the treatment of inflammatory breast cancer for Germany and Italy.

Data from a French placebo-controlled double-blind trial in 120 female patients treated with high dose fluorouracil, epirubicin and cyclophosphamide (HD-FEC) chemotherapy for inflammatory breast cancer were used to assess the economic impact of adjunctive lenograstim therapy. The analysis compared direct costs of treatment, with or without lenograstim, with reference to the Social Security (Germany) or to the National Health Service (Italy). Resource utilisation differed between the 2 treatment groups. The lenograstim group reported 32% fewer antibiotic therapy days (9.8 days vs 14.6; p = 0.01) and 24% fewer inpatient days for any reason other than chemotherapy (7.4 'excess' days vs 9.8). By reducing infection-related morbidity associated with a high dose chemotherapy regimen, lenograstim decreased treatment costs by DM 1794 and ItL 1.2 million, excluding the cost of lenograstim itself. Since lenograstim patients reported fewer chemotherapy delays (16.4 vs 30.5%) and, hence, benefited from 1.2 (p = 0.04) more chemotherapy days, the related cost was DM 1519 and ItL 0.9 million higher than for the placebo group. This cost difference would be expected to be smaller if the placebo group patients had been followed until completion of their full chemotherapy regimen. Assuming that the costs of chemotherapy were the same for both groups, the direct cost saving for the lenograstim group would be 30% in Germany and 34% in Italy.

Health needs, demand for health services and expenditure across social groups in Italy: an empirical investigation.

The shortage of empirical studies on socio-economic factors influencing demand for health care and inequalities across social groups is dramatic in the case of Italy. The present study aims at discussing these issues, although its results are to be considered mainly methodological, given the small dimension of the sample (n = 807). A survey was carried out in a 'qualitative' sample of 9 Local Health Units of different Italian regions. Attention was paid to report every 'illness episode', considered as a cause of demand for health services, within the reference period (4 weeks) in order to properly link health needs with utilization of health services and relative expenditure. The assessment of health status across social groups, using 4 different indicators, shows the weakest social groups as the most vulnerable. The same groups report higher per capita health services uses and expenditures than their morbidity conditions would require. Assuming equity to be defined as 'equal use for equal need' a particular use-need ratio is developed (i.e. health services used per illness episode) able to capture the 'intensity' of health services use and expenditure per need. The 'over-equity' towards the less favoured groups is interpreted as a possible accomplishment of the N.H.S. fundative goals. A structural model of determinants of health services utilization, carried out through the LISREL technique (R2 = 0.36), confirms the irrelevance of the social variables with respect to need variables.