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Biomedical subjects

John R Wilson

Publications and source records attributed to John R Wilson.

17 recordsLinked to original sources
PubMed2005

The nature of expertise: a review.

This paper reviews the complex topic of expertise. It begins with an explanation for the range of interest and viewpoints, and moves on to a discussion of the nature and study of expertise. The diversity in definitions, domains, disciplines, and the impact of these factors on approaches to investigation, are offered as possible explanations for some of the differences that appear to run through the literature. Specific attention is given to issues that may concern ergonomists interested in understanding expertise from the perspective of work in complex and dynamic settings. We suggest a move away from traditional novice-expert experimental designs to study of work in a naturalistic way, studying tasks and activities that are sufficiently challenging so that real expertise can be elicited.

Artificial Intelligence↗
PubMed2005

The Integrated Workload Scale (IWS): a new self-report tool to assess railway signaller workload.

Network Rail, who own the railway infrastructure in the UK, have been interested in the assessment of mental workload (MWL) of signallers and control staff for some years. A new model of MWL has been proposed within which to develop a suite of new MWL analytical and empirical assessment tools. One of these is the Integrated Workload Scale (IWS), developed and tested for signallers. This paper describes the development of the IWS and its subsequent testing within two full-scale simulator trials with an NX (entry/exit) panel and an Integrated Electrical Control Centre (IECC) system, and then in the field at signal boxes. The IWS has proven to be a valuable measure of individually experienced peaks and troughs in workload over a period of time or within a particular set of scenarios. It is acceptable to signallers and maps well onto assessments of expected workload on the basis of timeline analysis and subject matter expert commentaries.

Humans↗
PubMed2005

Rail human factors: Past, present and future.

Rail human factors research has grown rapidly in both quantity and quality of output over the past few years. There was an early base of work at a few institutions carried out over the 1960s and 1970s, followed by a lull in the 1980s and early 1990s. The continual influences of safety concerns, new technical system opportunities, reorganisation of the business, needs to increase effective, reliable and safe use of capacity, and increased society, media and government interest have now accelerated rail human factors research programmes in several countries. In this paper we review the literature on rail human factors research, covering driving, signalling and control, maintenance, reporting systems, passenger interests, planning and technical systems change. Current major rail human factors programmes are summarised and future research needs proposed. It is asserted that general human factors models and methods are being re-assessed, and new ones developed, to meet the requirements of the railways.

Adolescent↗
PubMed2005

Pre-transplant reversible pulmonary hypertension predicts higher risk for mortality after cardiac transplantation.

BACKGROUND: Pre-transplant fixed pulmonary hypertension is associated with higher post-transplant mortality. In this study, we assessed the significance of pre-transplant reversible pulmonary hypertension in patients undergoing cardiac transplantation. METHODS: Overall, we studied 182 patients with baseline normal pulmonary pressures or reversible pulmonary hypertension, defined as a decrease in pulmonary vascular resistance (PVR) to < or =2.5 Wood units (WU), who underwent cardiac transplantation. Multiple recipient and donor characteristics were assessed to identify independent predictors of mortality. RESULTS: The average duration of follow-up was 42 +/- 28 months. Forty patients (22%) died during the follow-up period. Baseline hemodynamics for alive vs dead patients were as follows: pulmonary artery systolic (PAS) 42 +/- 15 vs 52 +/- 15 mm Hg; PA diastolic 21 +/- 9 vs 25 +/- 9 mm Hg; PA mean 28 +/- 11 vs 35 +/- 10 mm Hg; transpulmonary gradient (TPG) 9 +/- 4 vs 11 +/- 7 mm Hg (all p < 0.05); total pulmonary resistance 7.7 +/- 4.8 vs 8.8 +/- 3.2 WU (p = 0.08); and PVR 2.3 +/- 1.5 vs 2.9 +/- 1.6 WU (p = 0.06). In an unadjusted analysis, patients with PAS >50 mm Hg had a higher risk of death (odds ratio [OR] 5.96, 95% confidence interval [CI] 1.46 to 19.84 as compared with PAS < or =30 mm Hg). There was no significant difference in survival among patients with baseline PVR <2.5, 2.5 to 4.0 or >4.0 WU, but patients with TPG > or =16 had a higher risk of mortality (OR 4.93, 95% CI 1.84 to 13.17). PAS pressure was an independent predictor of mortality (OR 1.04, 95% CI 1.02 to 1.06). Recipient body mass index, history of sternotomy; and donor ischemic time were the other independent predictors of mortality. CONCLUSION: Pre-transplant pulmonary hypertension, even when reversible to a PVR of < or =2.5 WU, is associated with a higher mortality post-transplant.

Adult↗
PubMed2005

Finding ergonomic solutions--participatory approaches.

This paper gives an overview of the theory of participatory ergonomics interventions and summary examples from a range of industries, including health care, military, manufacturing, production and processing, services, construction and transport. The definition of participatory approaches includes interventions at macro (organizational, systems) levels as well as micro (individual), where workers are given the opportunity and power to use their knowledge to address ergonomic problems relating to their own working activities. Examples are given where a cost-effective benefit has been measured using musculoskeletal sickness absence and compensation costs. Other examples, using different outcome measures, also showed improvements, for example, an increase in productivity, improved communication between staff and management, reduction in risk factors, the development of new processes and new designs for work environments and activities. Three cases are described from Canada and Japan where the participatory project was led by occupational health teams, suggesting that occupational health practitioners can have an important role to play in participatory ergonomics projects.

Ergonomics↗
PubMed2004

Selection of patients for heart transplantation in the current era of heart failure therapy.

OBJECTIVES: We sought to assess the relationship between survival, peak exercise oxygen consumption (VO(2)), and heart failure survival score (HFSS) in the current era of heart failure (HF) therapy. BACKGROUND: Based on predicted survival, HF patients with peak VO(2) <14 ml/min/kg or medium- to high-risk HFSS are currently considered eligible for heart transplantation. However, these criteria were developed before the widespread use of beta-blockers, spironolactone, and defibrillators-interventions known to improve the survival of HF patients. METHODS: Peak VO(2) and HFSS were assessed in 320 patients followed from 1994 to 1997 (past era) and in 187 patients followed from 1999 to 2001 (current era). Outcomes were compared between these two groups of patients and those who underwent heart transplantation from 1993 to 2000. RESULTS: Survival in the past era was 78% at one year and 67% at two years, as compared with 88% and 79%, respectively, in the current era (both p < 0.01). One-year event-free survival (without urgent transplantation or left ventricular assist device) was improved in the current era, regardless of initial peak VO(2): 64% vs. 48% for peak VO(2) <10 ml/min/kg (p = 0.09), 81% vs. 70% for 10 to 14 ml/min/kg (p = 0.05), and 93% vs. 82% for >14 ml/min/kg (p = 0.04). Of the patients with peak VO(2) of 10 to 14 ml/min/kg, 55% had low-risk HFSS and exhibited 88% one-year event-free survival. One-year survival after transplantation was 88%, which is similar to the 85% rate reported by the United Network for Organ Sharing for 1999 to 2000. CONCLUSIONS: Survival for HF patients in the current era has improved significantly, necessitating re-evaluation of the listing criteria for heart transplantation.

Algorithms↗
PubMed2004

A new model of scheduling in manufacturing: tasks, roles, and monitoring.

For over 3 decades there was a belief that computer-based solutions would "solve" complex industrial scheduling problems, yet most manufacturing organizations still require human contributions for effective scheduling performance. We present a new model of scheduling for the development and implementation of effective scheduling systems within manufacturing companies. The model derives from investigating the work of 7 schedulers in 4 manufacturing environments using a qualitative field study approach, for which novel field-based data collection and analysis methods were developed. The results show that scheduling in practice comprises task, role, and monitoring activities and that the business environment influences a scheduler at work. A new definition of scheduling is presented that includes the significant facilitation and implementation aspects of human scheduling ignored by many computer-based scheduling approaches. The implications for this model extend across the domains of human factors and operations management, especially for the analysis and improvement of existing and new production planning and control processes and enterprise information systems. Actual or potential applications of this research include the analysis, design, and management of planning, scheduling, and control processes in industry; the selection, training, and support of production schedulers; and the allocation of tasks to humans and computer systems in industrial planning, scheduling, and control processes.

Female↗
PubMed2003

Modeling the effects of functional performance and post-transplant comorbidities on health-related quality of life after heart transplantation.

BACKGROUND: Health-related quality of life and functional performance are important outcome measures following heart transplantation. This study investigates the impact of pre-transplant functional performance and post-transplant rejection episodes, obesity and osteopenia on post-transplant health-related quality of life and functional performance. METHODS: Functional performance and health-related quality of life were measured in 70 adult heart transplant recipients. A composite health-related quality of life outcome measure was computed via principal component analysis. Iterative, multiple regression-based path analysis was used to develop an integrated model of variables that affect post-transplant functional performance and health-related quality of life. RESULTS: Functional performance, as measured by the Karnofsky scale, improved markedly during the first 6 months post-transplant and was then sustained for up to 3 years. Rejection Grade > or =2 was negatively associated with health-related quality of life, measured by Short Form-36 and reversed Psychosocial Adjustment to Illness Scale scores. Patients with osteopenia had lower Short Form-36 physical scores and obese patients had lower functional performance. Path analysis demonstrated a negative direct effect of obesity (beta = - 0.28, p < 0.05) on post-transplant functional performance. Post-transplant functional performance had a positive direct effect on the health-related quality of life composite score (beta = 0.48, p < 0.001), and prior rejection episodes grade > or =2 had a negative direct effect on this measure (beta = -0.29, p < 0.05). Either directly or through effects mediated by functional performance, moderate-to-severe rejection, obesity and osteopenia negatively impact health-related quality of life. These findings indicate that efforts should be made to devise immunosuppressive regimens that reduce the incidence of acute rejection, weight gain and osteopenia after heart transplantation.

Bone Diseases, Metabolic↗
PubMed2003

Tolerability to beta-blocker therapy among heart failure patients in clinical practice.

BACKGROUND: Although beta-blockers were well-tolerated by heart failure (HF) patients in clinical trials, tolerability of these drugs in a general population of HF patients is not well-described. METHODS: We studied a total of 308 encounters with beta-blockers therapy in 268 ambulatory HF patients. Side effects and frequency and predictors of discontinuation of therapy were studied. Independent predictors of discontinuation were assessed. RESULTS: Weight gain (59%), fatigue (56%), dizziness (41%), and dyspnea (29%) were the most common side effects. Fifty-one patients (19%) were discontinued on therapy with any 1 particular beta-blocker. Fatigue (30%) and hypotension (28%) were the most common reasons for discontinuation. Forty (78%) of these were given a trial with a different beta-blocker. Of these, 22 (55%) attempts with a different beta-blocker were tolerated. Thus the overall absolute discontinuation rate was only 7% for patients who were given a trial with different beta-blockers or 11% for the entire study population. Independent predictors of discontinuation of therapy included advanced symptoms, nonischemic etiology, history of pulmonary disease, and higher diuretic doses. CONCLUSION: Side effects with beta-blockers in a general population of HF patients are common; however, with changes in medical management, most patients can tolerate them eventually. In case of intolerance to one kind, a trial with a different beta-blocker is indicated.

Adrenergic beta-Antagonists↗
PubMed2003

Preventing drowning through design--the contribution of human factors.

A number of routes can be followed towards the prevention of drowning, such as educating on water safety, installing barriers between non-intended users and water, mitigating the consequences of submersion incidents, and design. The human factor approach to safety is that design should always be the primary route. Human factors can be applied to the design of personal protective equipment such as buoyancy aids, barriers such as pool fencing, ancillary equipment such as swimming pool covers through to information and organisational factors such as safety signs and swimming campaigns. Design should consider all potential drowning scenarios and accommodate the characteristics of those at risk. A framework is presented with examples on how human factor principles can be applied to the design of potential drowning sites and products, with suggestions for methods and techniques that can be used in the key stages of predicting potential hazards and assessing risk.

Accident Prevention↗
PubMed2002

Left ventricular assist device implantation via left thoracotomy: alternative to repeat sternotomy.

Repeat sternotomy for left ventricular assist device insertion may result in injury to the right heart or patent coronary grafts, complicating intraoperative and postoperative management. In 4 critically ill patients, left thoracotomy was used as an alternative to repeat sternotomy. Anastomosis of the outflow conduit to the descending thoracic aorta provided satisfactory hemodynamic support.

Cardiac Surgical Procedures↗
PubMed2002

Characterizing neuropathies associated with monoclonal gammopathy of undetermined significance (MGUS): a framework consistent with classifying injuries according to fiber size.

Neuropathies associated with monoclonal gammopathy of undetermined significance (MGUS) occur frequently in the elderly. Data from 42 consecutive elderly patients with a MGUS-associated neuropathy - 12 patients with IgM MGUS, 25 patients with IgG MGUS, 5 patients with IgA MGUS - were evaluated prospectively using quantifiable clinical criteria and quantitative sensory testing. Results consistent with preferential injury to large fibers were found in patients with IgM isotypes (P <.005) but not in patients with IgG isotypes (P <.0005 to.0004). These findings support an immunologic origin for at least some MGUS-associated neuropathies and provide information important for the clinical evaluation of neuropathies in the elderly.

Aged↗
PubMedDate not supplied

A naturalistic study of railway controllers.

There is an increasing prevalence for work to be analysed through naturalistic study, especially using ethnographically derived methods of enquiry and qualitative field research. The relatively unexplored domain of railway control (in comparison to signalling) in the UK is described in terms of features derived from observations and semi-structured interviews. In addition, task diagrams (a technique taken from the Applied Cognitive Task Analysis toolkit) are used to represent controllers' core elements of work, i.e. to manage events or incidents, and to identify the challenging steps in the process. The work features identified, the task diagrams, and the steps identified as challenging form a basis from which future ergonomics studies on railway controllers in the UK will be carried out.

Cognition↗