Variations in vascular access flows in haemodialysis can depend on needle orientation

Introduction: While using the Transonic Qc[TM] machine to assess access flow in arteriovenous fistulae (AVF), we observed that when compared to antegrade arterial needle insertion, retrograde arterial needle insertion could regularly produce lower access flow measurements. This study sought to explore this phenomenon. Method: 23 patients entered and 20 finished the study. Patient selection criteria included: functioning AVF and an adequate AVF length for either retrograde or antegrade arterial needle insertion. After ensuring stable and similar blood pressures, 3 flow measurements were taken during the first 2 hours on the same dialysis day of 3 consecutive weeks using antegrade needle insertion then were repeated on 3 further consecutive weeks using retrograde insertion. Results: Overall, access flows measured with retrograde insertion were significantly lower by a mean difference of 107.15 ml/min (57-484 ml/min) than the flows measured with antegrade needle placement. In 5/20, 3 recorded minimal difference and 2 had a higher access flows during retrograde insertion. No recirculation was observed during either antegrade or retrograde needle insertion. The paired t-test showed that there was significant difference between the antegrade versus retrograde mean measurements (p = 0.005). Conclusion: Although the sample size is small and the number of measurements limited, we conclude that access flows may be greater with an antegrade arterial orientation compared to flows recorded with a retrograde orientation. The phenomenon behind this conclusion is yet to be investigated. We suggest that when using the Transonic Qc[TM] access measurement device the arterial needle should always be in the same direction for each measurement for each individual patient.<br /

Huge Seebeck coefficients in non-aqueous electrolytes

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

Fluid Convection, Generation and Reinfusion in Haemodiafiltration

Despite widespread use in clinical practice for over 30 years, many questions remain unanswered regarding fluid convection and reinfusion strategies in haemodiafiltration (HDF). Randomised controlled trials have failed to consistently demonstrate improved survival with convective therapies, but a dose-dependent improvement in outcome has been suggested. The ‘minimum’ and ‘ideal’ volumes of convection are undefined. Online generation of ultrapure dialysis fluid has allowed unprecedented convection volumes; however, delivery of fluid directly into the blood circuit requires strict monitoring. The replacement fluid may be reinfused at multiple points in the circuit. Post-dilution HDF is highly efficient in terms of solute clearance but is limited by haemoconcentration. Pre-dilution HDF prolongs filter life but requires significant convection volumes to achieve adequate solute clearance. Mid-dilution HDF utilises a specific dialyser, which is associated with additional cost and escalating transmembrane pressure. Mixed-dilution HDF appears to offer an attractive balance between solute clearance efficiency and haemoconcentration, however these findings need to be confirmed in large studies. The majority of trials comparing fluid reinfusion strategies have enrolled small numbers of patients over brief study periods. It is unclear whether high-quality evidence examining fluid convection and reinfusion will become available and practice may need to rely on observational data

Submerged in the mainstream? A case study of an immigrant learner in a New Zealand primary classroom

Immigrant children from diverse language backgrounds face not only linguistic challenges when enrolled in mainstream English-medium classrooms, but also difficulties adjusting to an unfamiliar learning community. The culture of primary school classrooms in New Zealand typically reflects conventions across three dimensions: interactional, instructional task performance and cognitive-academic development. All three dimensions are underpinned by the culturally specific discourse conventions involved in language socialisation. New learners may be helped by classmates or their teacher to understand and successfully use these conventions, but left on their own they may sink rather than swim. This is a case study of one Taiwanese 11-year old boy, 'John', who entered a New Zealand primary classroom midway through the school year. John's basic conversational ability was sound, but he did not possess the interactive classroom skills needed to operate in the new culture of learning. Selected from a wider study of the classroom, transcript data from audio-recorded excerpts of John's interactions over several months with his teacher and classmates are interpreted from perspectives derived from sociocultural and language socialisation theories. The article concludes with a brief consideration of the extent to which John constructed, or was constrained from constructing meaningful learning experiences, and suggestions for further research and reflection

Between overt and covert research: concealment and disclosure in an ethnographic study of commercial hospitality

This article examines the ways in which problems of concealment emerged in an ethnographic study of a suburban bar and considers how disclosure of the research aims, the recruitment of informants, and elicitation of information was negotiated throughout the fieldwork. The case study demonstrates how the social context and the relationships with specific informants determined overtness or covertness in the research. It is argued that the existing literature on covert research and covert methods provides an inappropriate frame of reference with which to understand concealment in fieldwork. The article illustrates why concealment is sometimes necessary, and often unavoidable, and concludes that the criticisms leveled against covert methods should not stop the fieldworker from engaging in research that involves covertness

Health-related quality of life in patients with inoperable malignant bowel obstruction: secondary outcome from a double-blind, parallel, placebo-controlled randomised trial of octreotide.

BACKGROUND:This analysis aims to evaluate health-related quality of life (HrQoL) (primary outcome for this analysis), nausea and vomiting, and pain in patients with inoperable malignant bowel obstruction (IMBO) due to cancer or its treatments randomised to standardised therapies plus octreotide or placebo over a maximum of 72 h in a double-blind clinical trial. METHODS:Adults with IMBO and vomiting recruited through 12 services spanning inpatient, consultative and community settings in Australia were randomised to subcutaneous octreotide infusion or saline. HrQoL was measured at baseline and treatment cessation (EORTC QLQ-C15-PAL). Mean within-group paired differences between baseline and post-treatment scores were analysed using Wilcoxon Signed Rank test and between group differences estimated using linear mixed models, adjusted for baseline score, sex, age, time, and study arm. RESULTS:One hundred six of the 112 randomised participants were included in the analysis (n = 52 octreotide, n = 54 placebo); 6 participants were excluded due to major protocol violations. Mean baseline HrQoL scores were low (octreotide 22.1, 95% CI 14.3, 29.9; placebo 31.5, 95% CI 22.3, 40.7). There was no statistically significant within-group improvement in the mean HrQoL scores in the octreotide (p = 0.21) or placebo groups (p = 0.78), although both groups reported reductions in mean nausea and vomiting (octreotide p < 0.01; placebo p = 0.02) and pain scores (octreotide p < 0.01; placebo p = 0.03). Although no statistically significant difference in changes in HrQoL scores between octreotide and placebo were seen, an adequately powered study is required to fully assess any differences in HrQoL scores. CONCLUSION:The HrQoL of patients with IMBO and vomiting is poor. Further research to formally evaluate the effects of standard therapies for IMBO is therefore warranted. TRIAL REGISTRATION:Australian New Zealand Clinical Trials Registry ACTRN12608000211369 (date registered 18/04/2008)

Variable geometries of connection: Urban digital divides and the uses of Information Technology

This paper proposes a new way of conceptualising urban ‘digital divides’. It focuses on the ways in which Information and Communication Technologies (ICTs) unevenly affect the pace of life within the urban environment. Based on a detailed case study of how ICT s are being used in an affluent and a marginalised neighbourhood in Newcastle-upon-Tyne, the paper suggests that urban digital divides need to be understood as more than uneven patterns of access. They emerge in this work as more than the presence or absence of specific technological artefacts. Rather, it is argued that different styles and speeds of technologically mediated life now work to define urban socio-spatial inequalities. The paper distinguishes between two such key styles and speeds. First, the paper argues that affluent and professional groups now use new media technologies pervasively and continuously as the ‘background’ infrastructure to sustain privileged and intensely distanciated, but time-stressed, lifestyles. Second, more marginalised neighbourhoods tend to be characterised by instrumental and episodic ICT usage patterns which are often collectively organised through strong neighbourhood ties. For the former, mediated networks help orchestrate neighbourhood ties; for the latter it is those neighbourhood ties that enable online access

Developing a Set of Core Outcomes for Trials in Haemodialysis: An International Delphi Survey

AIM: To generate a consensus-based, prioritized list of core outcomes for trials in haemodialysis. BACKGROUND: Survival and quality of life for patients on haemodialysis remain poor despite substantial research efforts. Existing trials often report surrogate outcomes that may not be relevant to patients and clinicians. A core outcome set that reflects stakeholder priorities would improve the relevance, efficiency, and comparability of haemodialysis trials. METHODS: In an online Delphi survey, participants rated the importance of outcomes using a 9-point Likert scale. In Round 2 and 3, participants reviewed the scores and comments of other respondents and re-rated the outcomes. For each outcome, we calculated the median, mean, and proportion rating 7-9 (“critically important”). RESULTS: 1,181 participants (202 [17%] patients/caregivers, 979 health professionals) from 73 countries completed Round 1 and 838 (150 [18%] patients/caregivers) completed Round 3 (71% response rate). Outcomes achieving consensus as high priorities across both groups were: vascular access complications, cardiovascular disease, mortality, dialysis adequacy and fatigue. Patients/caregivers rated four outcomes higher than health professionals: ability to travel (mean difference 0.9), dialysis-free time (0.5), dialysis adequacy (0.3), and washed out after dialysis (0.2). Health professionals rated 11 outcomes higher: mortality (1.0), hospitalization (1.0), drop in blood pressure (1.0), vascular access complications (0.9), depression (0.9), cardiovascular disease (0.8), target weight (0.7), infection (0.4), potassium (0.4), ability to work (0.3), and pain (0.3). CONCLUSIONS: The top stakeholder prioritized outcomes were vascular access problems, cardiovascular disease, mortality, dialysis adequacy and fatigue. Patients/caregivers gave higher priority to lifestyle-related outcomes than health professionals. This prioritized set of outcomes can inform the establishment of a core outcome set, to improve the value of trial evidence to support decision-making for people on haemodialysis