1,013 research outputs found

    Huge Seebeck coefficients in non-aqueous electrolytes

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    The Seeebeck coefficients of the non-aqueous electrolytes tetrabutylammonium nitrate, tetraoctylphosphonium bromide and tetradodecylammonium nitrate in 1-octanol, 1-dodecanol and ethylene-glycol are measured in a temperature range from T=30 to T=45 C. The Seebeck coefficient is generally of the order of a few hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here we report huge values of 7 mV/K at 0.1M concentration for tetrabutylammonium nitrate in 1-dodecanol. These striking results open the question of unexpectedly large kosmotrope or "structure making" effects of tetraalkylammonium ions on the structure of alcohols.Comment: Submitted to J. Chem. Phy

    Better informing decision making with multiple outcomes cost-effectiveness analysis under uncertainty in ost-disutility space

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    © 2015 McCaffrey et al. Introduction: Comparing multiple, diverse outcomes with cost-effectiveness analysis (CEA) is important, yet challenging in areas like palliative care where domains are unamenable to integration with survival. Generic multi-attribute utility values exclude important domains and nonhealth outcomes, while partial analyses - where outcomes are considered separately, with their joint relationship under uncertainty ignored - lead to incorrect inference regarding preferred strategies. Objective: The objective of this paper is to consider whether such decision making can be better informed with alternative presentation and summary measures, extending methods previously shown to have advantages in multiple strategy comparison. Methods: Multiple outcomes CEA of a home-based palliative care model (PEACH) relative to usual care is undertaken in cost disutility (CDU) space and compared with analysis on the cost-effectiveness plane. Summary measures developed for comparing strategies across potential threshold values for multiple outcomes include: expected net loss (ENL) planes quantifying differences in expected net benefit; the ENL contour identifying preferred strategies minimising ENL and their expected value of perfect information; and cost-effectiveness acceptability planes showing probability of strategies minimising ENL.Results: Conventional analysis suggests PEACH is cost-effective when the threshold value per additional day at home ( K1) exceeds 1,068 or dominated by usual care when only the proportion of home deaths is considered. In contrast, neither alternative dominate in CDU space where cost and outcomes are jointly considered, with the optimal strategy depending on threshold values. For example, PEACH minimises ENL when K1=2,000 and K2=2,000 (threshold value for dying at home), with a 51.6% chance of PEACH being cost-effective. Conclusion: Comparison in CDU space and associated summary measures have distinct advantages to multiple domain comparisons, aiding transparent and robust joint comparison of costs and multiple effects under uncertainty across potential threshold values for effect, better informing net benefit assessment and related reimbursement and research decisions

    Informed consent in palliative care clinical trials: challenging but possible

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    Obtaining informed consent is a key protection that should be afforded universally to people using health services and the basis around which any participation in clinical trials is built. Randomized controlled effectiveness studies are necessary to answer key questions in hospice and palliative care, in order to help systematically improve the quality of care. In order to be properly generalizable, such trials need to have broad inclusion criteria to reflect the population most likely to be affected by the condition. The inclusion of patients who are seriously ill, and therefore potentially vulnerable, requires careful exploration of ethical and legal principles that underpin informed consent. Specific challenges in obtaining informed consent for randomised clinical trials (RCTs) in clinically unstable populations such as hospice and palliative care include higher rates of people with impaired cognitive capacity as well as interventional studies in clinical situations which may present as a sudden change in condition. None of these challenges is unique to hospice and palliative care research, but the combination and frequency with which they are encountered require systematic and considered solutions. This article outlines five different ethically valid consent approaches and discusses their applicability to hospice and palliative care research trials. These include: consent by the patient (at the time of enrolment, in advance of the study, or delayed until after the study has commenced); a proxy (or legally authorised representative); or a consent waiver. Increased use of the less traditional modes of informed consent may lead to greater participation rates in hospice and palliative care trials, thereby improving the evidence base more rapidly in part by better reflecting the population served and hence improving generalizability

    Clinician-reported changes in octreotide prescribing for malignant bowel obstruction as a result of an adequately powered phase III study: A transnational, online survey

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    © The Author(s) 2018. Background: Translating research evidence into clinical practice often has a long lag time. Aim: To determine the impact of a phase III randomised controlled trial on palliative care clinicians’ self-reported practice change. Design: Online survey about use of octreotide in managing inoperable malignant bowel obstruction due to cancer or its treatments distributed in November 2016, 2 years after the first publication of the study in a peer-reviewed journal. Demographic, self-reported practice and the reasons underpinning this were collected. Responses were aggregated to ‘practice modified’ or ‘practice not modified’. A multinomial regression model explored predictors of practice change. Setting: Members of the Australian New Zealand Society of Palliative Medicine. Results: Response rate was 20.8% (106/509): 55.6% were aged >50 years, 56.5% were female and 77% had previously prescribed octreotide for this clinical indication. Out of 106 respondents, 52 (49.1%) indicated modified practice (60.9% of those who had previously prescribed octreotide in this setting). In those who reported practice change, most frequently octreotide was now used when other therapies failed; for not changing practice, ‘more confirmatory evidence was needed’ was most often cited. In the regression model, older age (clinician age = 50–59 years; relative risk = 0.147; 95% confidence interval = 0.024–0.918; p = 0.04) and having practices with lower proportions of people treated with octreotide (0%–20%; relative risk = 0.039; 95% confidence interval = 0.002–0.768; p = 0.033) predicted greater self-reported practice change. Conclusion: Clinician-reported change in practice in the survey is seen in the majority of respondents. This suggests that there is a cohort of ‘early adopters’ within palliative care practice as new evidence becomes available

    Elements of optimal paediatric palliative care for children and young people: An integrative review using a systematic approach

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    © 2014 Australian College of Nursing Ltd. Background: Models of palliative care need to address the unmet needs of children, young people and families. Objective: To undertake an integrative review to identify the key elements of optimal paediatric palliative care from the perspectives of children and young people with palliative care needs and their parents. Data sources: Electronic databases including CINAHL, Medline, PsycINFO and AMED searched using combined terms for palliative care, service models and children along with reference lists of included studies. Study selection: Peer reviewed empirical studies reporting on evaluation of paediatric palliative care by children and young people with palliative care needs (0-19 years), or their families, published in English, between 2000 and 2013. The views of health professionals and grey literature were excluded. Quality appraisal completed by two researchers, consensus reached following discussion. Data extraction and synthesis: Data extracted by two researchers, entered into an electronic proforma and synthesised using a narrative approach. Results: Seven studies were identified of which two were quantitative, one was qualitative and four were mixed methods. Synthesis highlighted the need for tailored support enabling flexibility in care, with specific reference to location of care and access to psychosocial support, 24. h specialist support, respite care and sibling support. Conclusions: Paediatric palliative care should be flexible, responsive and tailored to the needs of children and their families. Robust evaluation of models of care that incorporate these elements is required to inform optimal care

    “An ethnographic seduction”: how qualitative research and Agent-based models can benefit each other

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    We provide a general analytical framework for empirically informed agent-based simulations. This methodology provides present-day agent-based models with a sound and proper insight as to the behavior of social agents — an insight that statistical data often fall short of providing at least at a micro level and for hidden and sensitive populations. In the other direction, simulations can provide qualitative researchers in sociology, anthropology and other fields with valuable tools for: (a) testing the consistency and pushing the boundaries, of specific theoretical frameworks; (b) replicating and generalizing results; (c) providing a platform for cross-disciplinary validation of results

    Study protocol: A phase III randomised, double-blind, parallel arm, stratified, block randomised, placebo-controlled trial investigating the clinical effect and cost-effectiveness of sertraline for the palliative relief of breathlessness in people with chronic breathlessness

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    © Published by the BMJ Publishing Group Limited. Introduction: Breathlessness remains a highly prevalent and distressing symptom for many patients with progressive life-limiting illnesses. Evidence-based interventions for chronic breathlessness are limited, and there is an ongoing need for high-quality research into developing management strategies for optimal palliation of this complex symptom. Previous studies have suggested that selective serotonin reuptake inhibitors such as sertraline may have a role in reducing breathlessness. This paper presents the protocol for a large, adequately powered randomised study evaluating the use of sertraline for chronic breathlessness in people with progressive life-limiting illnesses. Methods and analysis: A total of 240 participants with modified Medical Research Council Dyspnoea Scale breathlessness of level 2 or higher will be randomised to receive either sertraline or placebo for 28 days in this multisite, double-blind study. The dose will be titrated up every 3 days to a maximum of 100 mg daily. The primary outcome will be to compare the efficacy of sertraline with placebo in relieving the intensity of worst breathlessness as assessed by a 0-100 mm Visual Analogue Scale. A number of other outcome measures and descriptors of breathlessness as well as caregiver assessments will also be recorded to ensure adequate analysis of participant breathlessness and to allow an economic analysis to be performed. Participants will also be given the option of continuing blinded treatment until either study data collection is complete or net benefit ceases. Appropriate statistical analysis of primary and secondary outcomes will be used to describe the wealth of data obtained. Ethics and dissemination: Ethics approval was obtained at all participating sites. Results of the study will be submitted for publication in peer-reviewed journals and the key findings presented at national and international conferences. Trial registration number ACTRN12610000464066

    Development of an invasively monitored porcine model of acetaminophen-induced acute liver failure

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    Background: The development of effective therapies for acute liver failure (ALF) is limited by our knowledge of the pathophysiology of this condition, and the lack of suitable large animal models of acetaminophen toxicity. Our aim was to develop a reproducible invasively-monitored porcine model of acetaminophen-induced ALF. Method: 35kg pigs were maintained under general anaesthesia and invasively monitored. Control pigs received a saline infusion, whereas ALF pigs received acetaminophen intravenously for 12 hours to maintain blood concentrations between 200-300 mg/l. Animals surviving 28 hours were euthanased. Results: Cytochrome p450 levels in phenobarbital pre-treated animals were significantly higher than non pre-treated animals (300 vs 100 pmol/mg protein). Control pigs (n=4) survived 28-hour anaesthesia without incident. Of nine pigs that received acetaminophen, four survived 20 hours and two survived 28 hours. Injured animals developed hypotension (mean arterial pressure; 40.8+/-5.9 vs 59+/-2.0 mmHg), increased cardiac output (7.26+/-1.86 vs 3.30+/-0.40 l/min) and decreased systemic vascular resistance (8.48+/-2.75 vs 16.2+/-1.76 mPa/s/m3). Dyspnoea developed as liver injury progressed and the increased pulmonary vascular resistance (636+/-95 vs 301+/-26.9 mPa/s/m3) observed may reflect the development of respiratory distress syndrome. Liver damage was confirmed by deterioration in pH (7.23+/-0.05 vs 7.45+/-0.02) and prothrombin time (36+/-2 vs 8.9+/-0.3 seconds) compared with controls. Factor V and VII levels were reduced to 9.3 and 15.5% of starting values in injured animals. A marked increase in serum AST (471.5+/-210 vs 42+/-8.14) coincided with a marked reduction in serum albumin (11.5+/-1.71 vs 25+/-1 g/dL) in injured animals. Animals displayed evidence of renal impairment; mean creatinine levels 280.2+/-36.5 vs 131.6+/-9.33 mumol/l. Liver histology revealed evidence of severe centrilobular necrosis with coagulative necrosis. Marked renal tubular necrosis was also seen. Methaemoglobin levels did not rise >5%. Intracranial hypertension was not seen (ICP monitoring), but there was biochemical evidence of encephalopathy by the reduction of Fischer's ratio from 5.6 +/- 1.1 to 0.45 +/- 0.06. Conclusion: We have developed a reproducible large animal model of acetaminophen-induced liver failure, which allows in-depth investigation of the pathophysiological basis of this condition. Furthermore, this represents an important large animal model for testing artificial liver support systems

    Off-label prescribing in palliative care – a cross-sectional national survey of Palliative Medicine doctors

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    Background: Regulatory bodies including the European Medicines Agency register medications (formulation, route of administration) for specific clinical indications. Once registered, prescription is at clinicians’ discretion. Off-label use is beyond the registered use. While off-label prescribing may, at times, be appropriate, efficacy and toxicity data are often lacking. Aim: The aim of this study was to document off-label use policies (including disclosure and consent) in Australian palliative care units and current practices by palliative care clinicians. Design: A national, cross-sectional survey was conducted online following an invitation letter. The survey asked clinicians their most frequent off-label medication/indication dyads and unit policies. Dyads were classified into unregistered, off-label and on-label, and for the latter, whether medications were nationally subsidised. Setting/participants: All Australian palliative medicine Fellows and advanced trainees. Results: Overall, 105 clinicians responded (53% response rate). The majority did not have policies on off-label medications, and documented consent rarely. In all, 236 medication/indication dyads for 36 medications were noted: 45 dyads (19%) were for two unregistered medications, 118 dyads (50%) were for 26 off-label medications and 73 dyads (31%) were for 12 on-label medications. Conclusions: Off-label prescribing with its clinical, legal and ethical implications is common yet poorly recognised by clinicians. A distinction needs to be made between where quality evidence exists but registration has not been updated by the pharmaceutical sponsor and the evidence has not been generated. Further research is required to quantify any iatrogenic harm from off-label prescribing in palliative care
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