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Polymer bounded explosives (PBXs) consist of energetic crystals coated with a polymer binder. These materials exhibit a highly heterogeneous microstructure. The initiation of the detonation phenomenon in PBXs is believed to be generated at the microstructure scale through hotspots. Hence, many of the explosives properties (initiation, desensitization, etc.) are understood as a direct consequence of their microstructure. Mesoscale modeling directly addresses the physics of hotspot formation. Unfortunately, high computational cost prevents their use on laboratory-sized and large scale experiments. In practice, continuum-scale models remain mandatory. We describe a new reactive burn model, named WGT, aiming to represent, at the continuum scale, some of the complexity of the PBX's microstructure. The initiation regime is driven by the shock temperature and results from surrogate modeling of the kinetics of a heterogeneous nucleation and growth model. The other regimes follow the formulation of the WHS2D2 reactive burn model and are driven by the local temperature. This model was calibrated on experimental results for PBX 9502 available in the literature, such as detonation velocity–curvature laws, Pop-plot data, or embedded electromagnetic particle velocity gauges. The model was also tested against desensitization and propagation data. [ABSTRACT FROM AUTHOR]

We propose to assess the performance of density functional theory calculations to predict the properties of CO2, H2O, and N2 fluids under high pressure (up to 40?GPa), which are representatives of not only detonation products but also giant planet interiors. Twenty-two generalized-gradient approximation functionals, presently in the ABINIT code, have been compared to molecular data and experimental equations of state of supercritical fluids. We found that the Perdew, Burke, and Ernzerhof (PBE) functional with Grimme's dispersion correction (D3) gives the best results. The residual error of PBE-D3 on pressure is estimated around 15%. [ABSTRACT FROM AUTHOR]

The KLRR perturbation theory has been initially proposed by Kang et al. in order to compute the equation of state (EOS) of a fluid of soft spheres represented by an EXP-6 potential. Victorov and Gubin have recently improved this method and they showed that, compared to other theories (namely HMSA/C and MCRSR), this improved KLRR theory turns out to be more accurate. In the first part of this paper, the comparison is extended to a larger range of temperature and stiffness of potential. Then, in order to use such a perturbation theory in a thermochemical code, the treatment of mixtures has to be handled since the KLRR method is expressed for a pure fluid. Usually, the Van-der-Waals one fluid mixing rule (VdW-1f) is employed. It consists in averaging the mixture by an effective fluid. We also intend here to re-evaluate this well-known and largely used model.

We present the calibration of the CARTE thermochemical code that allows to compute the properties of a wide variety of CHON explosives. We have developed an optimization procedure to obtain an accurate multicomponents EOS (fluid phase and condensed phase of carbon). We show here that the results of CARTE code are in good agreement with the specific data of molecular systems and we extensively compare our calculations with measured detonation properties for several explosives.

We compute the elastic stiffness tensor of fcc argon at 60 K and 1 bar using molecular simulation tools. Three different methods are investigated: explicit deformations of the simulation box, strain fluctuations at constant pressure and stress fluctuations at constant volume. Statistical ensemble sampling is done using molecular dynamics and Monte Carlo simulations. We observe a good agreement between the different methods and sampling algorithms excepted with molecular dynamics simulations in the (NpT) ensemble. There, we notice a strong dependence of the computed elastic constants with the barostat parameter, whereas molecular dynamics simulations in the (NVT) ensemble are not affected by the thermostat parameter. [ABSTRACT FROM AUTHOR]

Using orbital-free molecular dynamics simulations we study the structure and dynamics of increasingly asymmetric mixtures such as hydrogen-carbon, hydrogen-aluminium, hydrogen-copper, and hydrogen-silver. We show that, whereas the heavy component structure is close to an effective one-component plasma ( OCP), the light component appears more structured than the corresponding OCP. This effect is related to the crossover towards a Lorentz-type diffusion triggered by strongly coupled, highly charged heavy ions, and witnessed by the change of temperature scaling laws of diffusion. This over-correlation translates into an enhancement of nuclear reaction rates much higher than its classical OCP counterpart. [ABSTRACT FROM AUTHOR]

We present a parametrization of the pair correlation function and the static structure factor of the Coulomb one component plasma (OCP) from the weakly coupled regime to the strongly coupled regime. Recent experiments strongly suggest that the OCP model can play the role of a reference system for warm dense matter. It can provide the ionic static structure factor that is necessary to interpret the x-ray Thomson scattering measurements, for instance. We illustrate this with the interpretation of an x-ray diffraction spectrum recently measured, using a Bayesian method that requires many evaluations of the static structure factor to automatically calibrate the parameters. For strongly coupled dusty plasmas, the proposed parametrization of the Coulomb OCP pair correlation function can be related to the Yukawa one, including screening. Further prospects to parametrize the static structure of Yukawa systems are also discussed. [ABSTRACT FROM AUTHOR]

Background: Patient age may influence decisions to withhold life-sustaining treatments, independent of patients' preferences for or ability to benefit from such treatments. Controversy exists about the appropriateness of using age as a criterion for making treatment decisions.Objective: To determine the effect of age on decisions to withhold life-sustaining therapies.Design: Prospective cohort study.Setting: Five medical centers participating in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT).Patients: 9105 hospitalized adults who had one of nine illnesses associated with an average 6-month mortality rate of 50%.Measurements: Outcomes were the presence and timing of decisions to withhold ventilator support, surgery, and dialysis. Adjustment was made for sociodemographic characteristics, prognoses, baseline function, patients' preferences for life-extending care, and physicians' understanding of patients' preferences for life-extending care.Results: The median patient age was 63 years; 44% of patients were women, and 53% survived to 180 days. In adjusted analyses, older age was associated with higher rates of withholding each of the three life-sustaining treatments studied. For ventilator support, the rate of decisions to withhold therapy increased 15% with each decade of age (hazard ratio, 1.15 [95% CI, 1.12 to 1.19]); for surgery, the increase per decade was 19% (hazard ratio, 1.19 [CI, 1.12 to 1.27]); and for dialysis, the increase per decade was 12% (hazard ratio, 1.12 [CI, 1.06 to 1.19]). Physicians underestimated older patients' preferences for life-extending care; adjustment for this underestimation resulted in an attenuation of the association between age and decisions to withhold treatments.Conclusion: Even after adjustment for differences in patients' prognoses and preferences, older age was associated with higher rates of decisions to withhold ventilator support, surgery, and dialysis. [ABSTRACT FROM AUTHOR]

Objective: To examine the impact of illness on the families of seriously ill adults and to determine the correlates of adverse economic impact.Design: Data were collected during the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatment (SUPPORT), a prospective cohort study of outcomes, preferences, and decision making in seriously ill hospitalized adults and their families.Setting: Five tertiary care hospitals in the United States.Participants: The 2661 seriously ill patients in nine diagnostic categories who survived their index hospitalization and were discharged home were eligible for this analysis. Surrogate and/or patient interviews about the impact of illness on the family were obtained for 2129 (80%) of these patients (mean age, 62 years; 43% women; 6-month survival, 75%).Outcome Measures: Surrogates and patients were surveyed to determine the frequency of adverse caregiving and economic burdens. Multivariable analyses were performed to determine correlates of loss of family savings.Results: One third (34%) of patients required considerable caregiving assistance from a family member. In 20% of cases, a family member had to quit work or make another major life change to provide care for the patient. Loss of most or all of the family savings was reported by 31% of families, whereas 29% reported loss of the major source of income. Patient factors independently associated with loss of the family's savings on multivariable analysis included poor functional status (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.10 to 1.78 for patients needing assistance with three or more activities of daily living), lower family income (OR, 1.74; 95% CI, 1.37 to 2.21 for those with annual incomes below $25,000), and young age (OR, 2.85; 95% CI, 2.13 to 3.82 for those younger than 45 years compared with those 65 years or older).Conclusions: Many families of seriously ill patients experience severe caregiving and financial burdens. Families of younger, poorer, and more functionally dependent patients are most likely to report loss of most or all of the family's savings. [ABSTRACT FROM AUTHOR]

Background: Renal failure requiring dialysis in the setting of hospitalization for serious illness is a poor prognostic sign, and dialysis and aggressive care are sometimes withheld.Objective: To evaluate the clinical outcomes and cost-effectiveness of initiating dialysis and continuing aggressive care for seriously ill hospitalized patients.Design: Prospective cohort study and cost-effectiveness analysis.Setting: Five geographically diverse teaching hospitals.Patients: 490 patients (median age, 61 years; 58% women) enrolled in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) in whom dialysis was initiated.Measurements: Survival, functional status, quality of life, and health care costs. Life expectancy was estimated by extrapolating survival data (up to 4.4 years of follow-up) using a declining exponential function. Utilities (quality-of-life weights) were estimated by using time-tradeoff questions. Costs were based on data from SUPPORT and published Medicare data.Results: Median duration of survival was 32 days, and only 27% of patients were alive after 5 months. Survivors reported a median of one dependency in activities of daily living, and 62% rated their quality of life as "good" or better. Overall, the estimated cost per quality-adjusted life-year saved by initiating dialysis and continuing aggressive care rather than withholding dialysis and allowing death to occur was $128,200. For the 103 patients in the worst prognostic category, the estimated cost per quality-adjusted life-year was $274,100; for the 94 patients in the best prognostic category, the cost per quality-adjusted life-year was $61,900.Conclusions: For the few patients who survived, clinical outcomes were fairly good. With the exception of patients with the best prognoses, however, the cost-effectiveness of initiating dialysis and continuing aggressive care far exceeded $50,000 per quality-adjusted life-year, a commonly cited threshold for cost-effective care. [ABSTRACT FROM AUTHOR]

Background: Physicians are frequently unaware of patient preferences for end-of-life care. Identifying and exploring barriers to patient-physician communication about end-of-life issues may help guide physicians and their patients toward more effective discussions.Objective: To examine correlates and associated outcomes of patient communication and patient preferences for communication with physicians about cardiopulmonary resuscitation and prolonged mechanical ventilation.Design: Prospective cohort study.Setting: Five tertiary care hospitals.Patients: 1832 (85%) of 2162 eligible patients completed interviews.Measurements: Surveys of patient characteristics and preferences for end-of-life care; perceptions of prognosis, decision making, and quality of life; and patient preferences for communication with physicians about end-of-life decisions.Results: Fewer than one fourth (23%) of seriously ill patients had discussed preferences for cardiopulmonary resuscitation with their physicians. Of patients who had not discussed their preferences for resuscitation, 58% were not interested in doing so. Of patients who had not discussed and did not want to discuss their preferences, 25% did not want resuscitation. In multivariable analyses, patient factors independently associated with not wanting to discuss preferences for cardiopulmonary resuscitation included being of an ethnicity other than black (adjusted odds ratio [OR], 1.48 [95% CI, 1.10 to 1.99), not having an advance directive (OR, 1.35 [CI, 1.04 to 1.76]), estimating an excellent prognosis (OR, 1.72 [CI, 1.32 to 2.59]), reporting fair to excellent quality of life (OR, 1.36 [CI, 1.05 to 1.76]), and not desiring active involvement in medical decisions (OR, 1.33 [CI, 1.07 to 1.65]). Factors independently associated with wanting to discuss preferences for resuscitation but not doing so included being black (OR, 1.53 [CI, 1.11 to 2.11]) and being younger (OR, 1.14 per 10-year interval younger [CI, 1.04 to 1.25]).Conclusions: Among seriously ill hospitalized adults, communication about preferences for cardiopulmonary resuscitation is uncommon. A majority of patients who have not discussed preferences for end-of-life care do not want to do so. For patients who do not want to discuss their preferences, as well as patients with an unmet need for such discussions, failure to discuss preferences for cardiopulmonary resuscitation and mechanical ventilation may result in unwanted interventions. [ABSTRACT FROM AUTHOR]

Background: Alleviating the problems faced by dying persons and their families has drawn substantial public attention, but little is known about the experience of dying.Objective: To characterize the experience of dying from the perspective of surrogate decision makers, usually close family members (89%).Design: Prospective cohort study.Setting: Five teaching hospitals.Patients: Persons who had one of nine serious medical conditions or were 80 years of age or older who died and for whom a surrogate decision maker completed an interview about the death.Measurements: Medical records were reviewed and surrogate decision makers were interviewed.Results: 4124 of 9105 seriously ill patients died (46%); 408 of 1176 elderly patients died (35%). The patients' family members were interviewed after 3357 persons (73%) had died. Of 1541 patients who survived the enrollment hospitalization, 46% died during a later hospitalization. In the last 3 days of life, 55% of patients were conscious. Among these patients, pain, dyspnea, and fatigue were prevalent. Four in 10 patients had severe pain most of the time. Severe fatigue affected almost 8 in 10 patients. More than 1 in 4 patients had moderate dysphoria. Sixty-three percent of patients had difficulty tolerating physical or emotional symptoms. Overall, 11% of patients had a final resuscitation attempt. A ventilator was used in one fourth of patients, and a feeding tube was used in four tenths of patients. Most patients (59%) were reported to prefer a treatment plan that focused on comfort, but care was reported to be contrary to the preferred approach in 10% of cases.Conclusions: Most elderly and seriously ill patients died in acute care hospitals. Pain and other symptoms were commonplace and troubling to patients. Family members believed that patients preferred comfort, but life-sustaining treatments were often used. These findings indicate important opportunities to improve the care of dying patients. [ABSTRACT FROM AUTHOR]

Objective: To develop a model estimating the probability of an adult patient having severe functional limitations 2 months after being hospitalized with one of nine serious illnesses.Design: Prospective cohort study.Setting: Five teaching hospitals in the United States.Participants: 1746 patients (model development) who survived 2 months and completed an interview, selected from 4301 patients in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT); independent validation sample of 2478 patients.Measurements and Main Outcomes: Patient function 2 months after admission categorized as absence or presence of severe functional limitations (defined as Sickness Impact Profile scores > or = 30 or as activities of daily living scores > or = 4 [levels that require near-constant personal assistance]). A logistic regression model was constructed to predict severe functional limitation.Results: One third (n = 590) of patients who were interviewed at 2 months had severe functional limitations. Changes in functional status were common: Of those with no baseline dependencies (not dependent on personal assistance), 21% were severely limited at 2 months; of those with 4 or more baseline limitations, 30% had improved. The patient's ability to do activities of daily living was the most important predictor of functional status. Physiologic abnormalities, diagnosis, days in hospital, age, quality of life, and previous exercise capacity also contributed substantially. Model performance, assessed using receiver-operating characteristic curves, was 0.79 for the development sample and 0.75 for the validation sample. The model was well calibrated for the entire risk range.Conclusions: Functional outcome varied substantially after hospitalization for a serious illness. A small amount of readily available clinical information can estimate the probability of severe functional limitations. [ABSTRACT FROM AUTHOR]

An extension of the model described in a previous work (see Maillet J. B. et al., EPL, 78 (2007) 68001) based on Dissipative Particle Dynamics is presented and applied to a liquid high explosive (HE), with thermodynamic properties mimicking those of liquid nitromethane. Large scale nonequilibrium simulations of reacting liquid HE with model kinetic under sustained shock conditions allow a better understanding of the shock-to-detonation transition in homogeneous explosives. Moreover, the propagation of the reactive wave appears discontinuous since ignition points in the shocked material can be activated by the compressive waves emitted from the onset of chemical reactions. [ABSTRACT FROM AUTHOR]

In the field of detonation science or shock physics, predicting the thermo- dynamic properties and chemical compositions of detonation products of CHON systems (outcome of the decomposition of explosives) over a wide range of temperature and pressure with a very small computational cost is of great importance. Thermochemical codes such as the CARTE code use several methods published in the literature to compute the properties of these CHON systems. In this work, we evaluate the accuracy of the recently improved KLRR perturbation method and we propose a new mixing rule to reduce the fluid mixture to an effective pure fluid. Then, the results obtained with these two contributions are presented. [ABSTRACT FROM AUTHOR]

We present the results of the optimization of a classical molecular force field used to calculate the properties of shocked nitromethane by Monte Carlo simulations. The optimization technique allows a good transferability of the potential parameters on a broad range of thermodynamic conditions (temperature and pressure) since a large variety of reference data can be used in the optimization procedure, including densities, vaporization enthalpies or pressures along the Hugoniot curve. Results of calculated properties of shocked nitromethane are in good agreement with experimental shock Hugoniot data, including temperature measurements of second shock Hugoniot. [ABSTRACT FROM AUTHOR]

Violent conduct by youths ranks among the types of inappropriate behavior generally originating in difficult family and social contexts. A proper understanding of the development of violent conduct must consider the situation taken as a whole. This article documents the results of a qualitative study which aimed to determine the psychosocial profiles and needs of youths with serious behavior problems and a family history of physical, psychological or sexual abuse. The results are based on the review of clinical files of 12 boys and 11 girls between the ages of 9 and 17, who were under child protection. The 23 files were analyzed to document the simultaneous evolution of behavior problems, abuse, family and school context, and the intervention of child protection services (reporting, evaluation, measures taken, foster care). The qualitative analysis followed the chronology and life history of each youth, resulting in the emergence of three generic profiles: the Undesirable, the Explosive, and the Delinquent. Each of the profiles is described and placed in perspective using the attachment, trauma and socialization theories respectively. The study concludes with proposals of distinct intervention models to be applied to these youths in the school environment. [ABSTRACT FROM AUTHOR]

The study evaluated the effect of a programme for elementary school students with behaviour problems integrated into the regular classroom. The programme combined in-class social skills training and specific educational activities with peers, namely cooperative learning and tutoring by a prosocial peer. The innovative aspect is that the social status and affiliations of children with behaviour problems are key components in the matching of children during peer support. The goal is to improve social behaviour and to change peer perception through interventional strategies, therefore improving social reputation. Pre-test/post-test control group design was used. Results from traditional analysis indicated no significant difference between treatment and control groups after the programme. A modest effect size showed a relative improvement for students with behavioural disorders who participated in social skills training. Results are discussed in terms of the role of friends in the intervention programme. [ABSTRACT FROM AUTHOR]

Background: Previous studies suggest that specialty care is more costly but may produce improved outcomes for patients with acute cardiac illnesses.Objective: To determine whether patients with congestive heart failure who are cared for by cardiologists experienced differences in costs, care patterns, and survival compared with patients of generalists.Design: Prospective cohort study.Setting: 5 U.S. teaching hospitals between 1989 and 1994.Patients: 1298 patients hospitalized with an exacerbation of congestive heart failure.Measurements: Hospital costs; average daily Therapeutic Intervention Scoring System (TISS) score; and survival censored at 30, 180, and 365 days and 31 December 1994.Results: Compared with patients of generalists, patients of cardiologists were younger (mean age, 63.3 and 71.4 years; P < 0.001) and had lower Acute Physiology Scores at the time of admission (35.1 and 36.7; P < 0.001) but were more likely to have a history of ventricular arrhythmias (21.0% and 10.2%; P < 0.001). At 6 months, 201 (27%) patients of cardiologists and 149 (27%) patients of generalists had died. After adjustment for sociodemographic characteristics and severity of illness, patients of cardiologists incurred costs that were 42.9% (95% CI, 27.8% to 59.8%) higher and average daily TISS scores that were 2.83 points (CI, 1.96 to 3.68 points) higher than those of patients of generalists. Patients of cardiologists were more likely to undergo right-heart catheterization (adjusted odds ratio, 2.9 [CI, 1.7 to 4.9]) or cardiac catheterization (adjusted odds ratio, 3.9 [CI, 2.4 to 6.2]) and had higher odds for transfer to an intensive care unit and electrocardiographic monitoring. Adjusted survival did not differ significantly between groups at 30 days; however, there was a trend toward improved survival among patients of cardiologists at 1 year (adjusted relative hazard, 0.82 [CI, 0.65 to 1.04]) and at maximum follow-up (adjusted relative hazard, 0.80 [CI, 0.66 to 0.96]).Conclusions: In this observational study of patients hospitalized with congestive heart failure, cardiologist care was associated with greater costs and resource use and no difference in survival at 30 days of follow-up. Whether the trend toward better survival at longer follow-up represents differences in care or unadjusted illness severity is uncertain. [ABSTRACT FROM AUTHOR]

Objective: To examine the association between the use of right heart catheterization (RHC) during the first 24 hours of care in the intensive care unit (ICU) and subsequent survival, length of stay, intensity of care, and cost of care.Design: Prospective cohort study.Setting: Five US teaching hospitals between 1989 and 1994.Subjects: A total of 5735 critically ill adult patients receiving care in an ICU for 1 of 9 prespecified disease categories.Main Outcome Measures: Survival time, cost of care, intensity of care, and length of stay in the ICU and hospital, determined from the clinical record and from the National Death Index. A propensity score for RHC was constructed using multivariable logistic regression. Case-matching and multivariable regression modeling techniques were used to estimate the association of RHC with specific outcomes after adjusting for treatment selection using the propensity score. Sensitivity analysis was used to estimate the potential effect of an unidentified or missing covariate on the results.Results: By case-matching analysis, patients with RHC had an increased 30-day mortality (odds ratio, 1.24; 95% confidence interval, 1.03-1.49). The mean cost (25th, 50th, 75th percentiles) per hospital stay was $49 300 ($17 000, $30 500, $56 600) with RHC and $35 700 ($11 300, $20 600, $39 200) without RHC. Mean length of stay in the ICU was 14.8 (5, 9, 17) days with RHC and 13.0 (4, 7, 14) days without RHC. These findings were all confirmed by multivariable modeling techniques. Subgroup analysis did not reveal any patient group or site for which RHC was associated with improved outcomes. Patients with higher baseline probability of surviving 2 months had the highest relative risk of death following RHC. Sensitivity analysis suggested that a missing covariate would have to increase the risk of death 6-fold and the risk of RHC 6-fold for a true beneficial effect of RHC to be misrepresented as harmful.Conclusion: In this observational study of critically ill patients, after adjustment for treatment selection bias, RHC was associated with increased mortality and increased utilization of resources. The cause of this apparent lack of benefit is unclear. The results of this analysis should be confirmed in other observational studies. These findings justify reconsideration of a randomized controlled trial of RHC and may guide patient selection for such a study. [ABSTRACT FROM AUTHOR]

Objective: To develop and validate a prognostic model that estimates survival over a 180-day period for seriously ill hospitalized adults (phase I of SUPPORT [Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments]) and to compare this model's predictions with those of an existing prognostic system and with physicians' independent estimates (SUPPORT phase II).Design: Prospective cohort study.Setting: 5 tertiary care academic centers in the United States.Participants: 4301 hospitalized adults were selected for phase I according to diagnosis and severity of illness; 4028 patients were evaluated from phase II.Measurements: A survival model was developed using the following predictor variables: diagnosis, age, number of days in the hospital before study entry, presence of cancer, neurologic function, and 11 physiologic measures recorded on day 3 after study entry. Physicians were interviewed on day 3. Patients were followed for survival for 180 days after study entry.Results: The area under the receiver-operating characteristics (ROC) curve for prediction of surviving 180 days was 0.79 in phase I, 0.78 in the phase II independent validation, and 0.78 when the acute physiology score from the APACHE (Acute Physiology, Age, Chronic Health Evaluation) III prognostic scoring system was substituted for the SUPPORT physiology score. For phase II patients, the SUPPORT model had equal discrimination and slightly improved calibration compared with physician's estimates. Combining the SUPPORT model with physician's estimates improved both predictive accuracy (ROC curve area = 0.82) and the ability to identify patients with high probabilities of survival or death.Conclusions: A limited amount of readily available clinical information can provide a foundation for long-term survival estimates that are as accurate as physicians' estimates. The best survival estimates combine an objective prognosis with a physician's clinical estimate. [ABSTRACT FROM AUTHOR]

BACKGROUND: Serious illness often causes economic hardship for patients' families. However, it is not known whether this hardship is associated with a preference for the goal of care to focus on maximizing comfort instead of maximizing life expectancy or whether economic hardship might give rise to disagreement between patients and surrogates over the goal of care. METHODS: We performed a cross-sectional study of 3158 seriously ill patients (median age, 63 years; 44% women) at 5 tertiary medical centers with 1 of 9 diagnoses associated with a high risk of mortality. Two months after their index hospitalization, patients and surrogates were surveyed about patients' preferences for the primary goal of care: either care focused on extending life or care focused on maximizing comfort. Patients and surrogates were also surveyed about the financial impact of the illness on the patient's family. RESULTS: A report of economic hardship on the family as a result of the illness was associated with a preference for comfort care over life-extending care (odds ratio, 1.26; 95% confidence interval, 1.07-1.48) in an age-stratified bivariate analysis. Similarly, in a multivariable analysis controlling for patient demographics, illness severity, functional dependency, depression, anxiety, and pain, economic hardship on the family remained associated with a preference for comfort care over life-extending care (odds ratio, 1.31; 95% confidence interval, 1.10-1.57). Economic hardship on the family did not affect either the frequency or direction of patient-surrogate disagreements about the goal of care. CONCLUSIONS: In patients with serious illness, economic hardship on the family is associated with preferences for comfort care over life-extending care. However, economic hardship on the family does not appear to be a factor in patient-surrogate disagreements about the goal of care. [ABSTRACT FROM AUTHOR]

Objective: To investigate the appropriateness of hospitalization as the time to elicit patients' medical care preferences, the authors evaluated the capability of seriously ill patients to participate in decision making early in hospitalization and their decision making capacity two weeks before hospital entry.Design: Cross-sectional study with retrospective evaluation of preadmission decision making capacity.Setting: Five acute care teaching hospitals.Patients: Four thousand three hundred one acutely ill hospitalized adults meeting predetermined severity of illness criteria in nine specific disease categories.Measurements: Surrogate decision makers' estimates of the prior mental capacities of patients unable to be interviewed early in hospitalization about care preferences due to intubation, coma, or cognitive impairment. Comparison of the demographics, degrees of sickness at admission, and outcomes of interviewable vs noninterviewable patients.Main Results: Forty percent of the patients were not interviewable concerning preferences. Of these, 83% could have participated in treatment decisions two weeks prior to hospitalization. The patients who were not interviewable were more acutely ill, had less chronic disease, and were more likely to die during hospitalization than the interviewable patients.Conclusions: Many acutely ill patients likely to die in the hospital lost their ability to make medical care decisions around the time of hospital admission. Preferences for care and advance directives should be discussed in the outpatient setting or very early in hospital admission. [ABSTRACT FROM AUTHOR]

Objective: To address a patient care problem suggested by a quality assurance study: Should physicians of patients with atrial fibrillation who have not had echocardiography performed be encouraged to obtain echocardiograms in order to discover heretofore undetected mitral stenosis, which could be treated with anticoagulation, in order to avert strokes?Design: Decision analysis using a Markov-chain technique and quality-adjusted life expectancy.Setting: Outpatient clinics.Patients: Patients aged 40-80 years with chronic atrial fibrillation.Interventions: The following strategies were studied: 1) obtain echocardiograms for all patients and anticoagulate those with mitral stenosis; 2) anticoagulate patients with classic auscultatory sounds of mitral stenosis and obtain echocardiograms for patients with other murmurs; if an echocardiogram reveals mitral stenosis, anticoagulate; 3) anticoagulate all patients with murmurs; 4) anticoagulate all patients; 5) observe all patients (natural history).Main Results: The base analysis, using data available in the literature and on site, indicated that though performing echocardiography on all patients with atrial fibrillation gave the best quality-adjusted life expectancy, the differences among the five strategies studied were small. In addition, sensitivity analysis revealed that the decision was sensitive to many of the variables used in the analysis, especially the efficacy and the risks of anticoagulation.Conclusion: A recommendation that cardiac ultrasonography be done for all patients with atrial fibrillation in order to detect clinically unrecognized mitral stenosis cannot be made. [ABSTRACT FROM AUTHOR]