Development of a wheelchair stability assessment system: design tools and approaches

This chapter describes how design has been applied to the development of a system for supporting the prescription of wheelchairs. With an ageing population there is likely to be a continued rise in wheelchair usage, as well as wheelchair modifications for specific needs such as specialist seating and the addition of assistive devices. Ensuring the ease of use, stability, safety and performance of wheelchairs both occupied by, and attended to by older adults is an important consideration. This chapter describes the design methods employed in the development of WheelSense®, a system for use by wheelchair prescribers to support the assessment, adaptation and tuning of wheelchairs to meet individual needs. The system development has required a multidisciplinary approach bringing together designers, engineers, human factors specialists, clinical specialists alongside end-users and stakeholders. The resulting WheelSense® system combines electronics and a weighing system in a folding platform. It is supported by a handheld device and graphic user interface (GUI) for guiding the prescription process, enabling data entry and to support education of the wheelchair user chair

Hyponatremia at autopsy: An analysis of etiologic mechanisms and their possible significance

© 2008 Springer. Part of Springer Science+Business MediaWhile electrolyte measurements after death may be confounded by a number of variables, vitreous humor sodium tends to remain stable for some time, enabling correlation between ante- and postmortem levels. Review of natural and unnatural causes of reduced vitreous humor sodium levels at autopsy was undertaken to demonstrate the range of diseases that may result in this finding. Natural diseases affecting the vasopressin–renin–angiotensin axis may cause reduction in sodium levels with associated hypovolemia, euvolemia, and hypervolemia. Low sodium measurements may also occur with redistribution of water, and artefactually when there are underlying lipid and protein disorders. Unnatural causes of hyponatremia at autopsy include water intoxication from psychogenic polydipsia, environmental polydipsia, ingestion of dilute infant formulas, beer potomania, endurance exercise, fresh water immersion (including water births) and iatrogenic causes including drug and parenteral fluid administration, and surgical irrigation. A knowledge of the range of conditions that may result in lowered postmortem sodium levels will help to exclude or confirm certain diseases at autopsy. In addition, significant vitreous hyponatremia may be a useful finding to help clarify mechanisms of unnatural deaths.Angela Byramji, Glenda Cains, John D. Gilbert and Roger W. Byar

General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial

BACKGROUND: The effect of carotid endarterectomy in lowering the risk of stroke ipsilateral to severe atherosclerotic carotid-artery stenosis is offset by complications during or soon after surgery. We compared surgery under general anaesthesia with that under local anaesthesia because prediction and avoidance of perioperative strokes might be easier under local anaesthesia than under general anaesthesia. METHODS: We undertook a parallel group, multicentre, randomised controlled trial of 3526 patients with symptomatic or asymptomatic carotid stenosis from 95 centres in 24 countries. Participants were randomly assigned to surgery under general (n=1753) or local (n=1773) anaesthesia between June, 1999 and October, 2007. The primary outcome was the proportion of patients with stroke (including retinal infarction), myocardial infarction, or death between randomisation and 30 days after surgery. Analysis was by intention to treat. The trial is registered with Current Control Trials number ISRCTN00525237. FINDINGS: A primary outcome occurred in 84 (4.8%) patients assigned to surgery under general anaesthesia and 80 (4.5%) of those assigned to surgery under local anaesthesia; three events per 1000 treated were prevented with local anaesthesia (95% CI -11 to 17; risk ratio [RR] 0.94 [95% CI 0.70 to 1.27]). The two groups did not significantly differ for quality of life, length of hospital stay, or the primary outcome in the prespecified subgroups of age, contralateral carotid occlusion, and baseline surgical risk. INTERPRETATION: We have not shown a definite difference in outcomes between general and local anaesthesia for carotid surgery. The anaesthetist and surgeon, in consultation with the patient, should decide which anaesthetic technique to use on an individual basis. FUNDING: The Health Foundation (UK) and European Society of Vascular Surgery