Publications by authors named "Christopher Imray"

Weight and skin-fold measurements were made at five-day intervals during a 47-day expedition by six men and three women from the edge of the sea ice to the South Pole. From these, together with detailed manual records of the nutrition for individual participants, the average daily energy expenditure was determined before and after a resupply at approximately mid-point of the expedition. For all participants body weight fell during the expedition with the overall loss being much smaller for the three female participants (-4.

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The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for the prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management.

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Background: Vascular disease is a common cause of death and disability in our growing elderly population and the demand for vascular procedures is increasing worldwide. Workforce planning is essential to meet future demand and provide safe vascular services. Our aim was to evaluate the current workforce in the United Kingdom and estimate future demand for vascular surgeons.

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Nonfreezing cold injury (NFCI) is caused by prolonged exposure to cold, usually wet conditions and represents a separate pathological entity from frostbite. The pathophysiology of NFCI is characterized by vasoconstriction and microcirculatory disturbance. Iloprost, a synthetic prostaglandin analogue with vasodilatory properties is a recognized adjuvant treatment in frostbite; however, its role in NFCI is unclear.

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Background: Patients with symptomatic internal carotid artery (ICA) stenosis are at high risk of recurrent ischemic stroke and require early interventional treatment and antiplatelet therapy. Increased bleeding rates might counterbalance the periprocedural efficacy of intensified platelet inhibition. We aim to investigate, whether Revacept, a competitive antagonist of glycoprotein VI, adjunct to standard antiplatelet therapy reduces the occurrence of ischemic lesions in patients with symptomatic ICA stenosis.

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Background: Occupational burnout is a growing concern in frontline roles such as vascular surgery, and is associated with medical errors and shortened careers. Our aim is to measure burnout, resilience, and associated risk factors among vascular surgeons (VS) in the United Kingdom (UK).

Methods: We carried out an electronic survey of active VS in the UK using validated self-report questionnaires, including the following: Copenhagen Burnout Inventory (CBI), Brief Resilience Scale (BRS), and information on job characteristics, health, and well-being.

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Background: HLA incompatible renal transplantation still remains one of best therapeutic options for a subgroup of patients who are highly sensitized and difficult to match but not much is known about its long-term graft and patient survival.

Methods: One hundred thirty-four HLA incompatible renal transplantation patients from 2003 to 2018 with a median follow of 6.93 y were analyzed retrospectively to estimate patient and graft survivals.

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There is limited evidence regarding the impact of allograft nephrectomy (AN) on the long-term outcome of subsequent kidney re-transplantation compared with no prior allograft nephrectomy. The aim of the present study was to conduct a systematic review and meta-analysis to estimate the accumulation of evidence over time. Primary outcomes were 5-year graft and patient survival.

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Anti-HLA-antibody characteristics aid to risk-stratify patients and improve long-term renal graft outcomes. Complement activation by donor-specific antibody (DSA) is an important characteristic that may determine renal allograft outcome. There is heterogeneity in graft outcomes within the moderate to high immunological risk cases (cross-match-positive).

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Introduction: Nonfreezing cold injury (NFCI) is a peripheral cold injury that occurs when the extremities are exposed to cold temperatures, at or near the freezing point, for sustained periods of time (48-96 h at temperatures of usually around 0 to 6°C with associated wind chill). Although NFCI often goes unreported and may be underdiagnosed, it is a cause of significant morbidity in those working in cold conditions, particularly those in the military. Thus, further research into the prevention, recognition, and treatment of NFCI is warranted.

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Objectives: The incidence of acute kidney injury (AKI) after open (OAR) or endovascular (EVAR) aortic repair is unknown. This research assessed the proportion of patients who develop AKI after aortic intervention using validated criteria, and explored AKI risk factors.

Methods: This was a multicentre national prospective cohort study.

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Background: Cardiopulmonary exercise testing (CPET) provides an objective assessment of functional capacity and fitness. It can be used to guide decision making prior to major vascular surgery. The EVAR-2 trial suggested that endovascular aneurysm repair (EVAR) in patients unfit for open repair failed to provide a significant survival advantage over nonsurgical management.

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Objectives: In periods of cerebral ischaemia, adenosine triphosphate is metabolised, leading to accumulation of adenosine inosine and hypoxanthine. These can be measured in real time using peripheral blood samples intraoperatively. The primary aim of this study was to describe changes in purine concentrations in a cohort of patients undergoing carotid endarterectomy under general anaesthetic, and to evaluate correlation between changes in values with major perioperative steps.

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The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management.

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During periods of ischemia and hypoxia, intracellular adenosine triphosphate stores are rapidly depleted. Its metabolism results in release of purine nucleosides into the systemic circulation. While the potential of purine nucleosides as a biomarker of ischemia has long been recognized, this has been limited by their complex physiological role and inherent instability leading to problematic sampling and prolonged, complex analysis procedures.

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Background: Early neurological deterioration (END) is common after stroke. Prediction could identify patients requiring additional monitoring and intervention. Purines, breakdown products of adenosine triphosphate which accumulate during acute hypoxia, may reflect the subclinical presence of vulnerable tissue.

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Purpose: Our aim was to assess retinal venous diameter and segmented retinal layer thickness variation in acute systemic hypoxia with and without acetazolamide and to relate these changes to high altitude headache (HAH), as a proxy for intracerebral pathophysiology.

Methods: A total of 20 subjects participated in a 4-day ascent to the Margherita Hut (4,559 m) on Monte Rosa in the Italian Alps. Each participant was randomized to either oral acetazolamide 250 mg twice daily or placebo.

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Extremities are the area of the body most commonly affected by frostbite, which can also affect the face, ears, perineum, or genitals. Optimum management has moved away from early amputation and debridement toward maximizing tissue preservation and delaying surgical intervention. Increasing length of digit amputation increases morbidity, in terms of loss of hand function, experienced by patients.

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This paper reports the metabolic energy changes in six women who made the first unsupported traverse of Antarctica, covering a distance of 1,700 km in 61 days, hauling sledges weighing up to 80 kg. Pre- and postexpedition, measurements of energy expenditure and substrate utilization were made on all six members of the expedition over a 36-h period in a whole body calorimeter. During the study, subjects were fed an isocaloric diet: 50% carbohydrate, 35% fat, and 15% protein.

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Purpose: To explore the effects of the first all-female transantarctic expedition on hormonal axes pertinent to reproductive and metabolic function.

Methods: Six females (age, 28-36 yr; body mass index, 24.2 ± 0.

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Background: Cerebral microemboli may lead to ischaemic neurological complications after carotid endarterectomy (CEA). The association between classical cardiovascular risk factors and acute cerebral microemboli following carotid surgery has not been studied. The aim of this study was to explore whether an established cardiovascular risk score (Pocock score) predicts the presence of cerebral microemboli acutely after CEA.

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Frostbite and other cold-related injuries commonly develop during prolonged exposure to the low environmental temperatures of polar and mountainous regions. Hypoxia is a potent sympathetic stimulus that causes vasoconstriction of the peripheral blood vessels, which may further compound the risk of developing a cold-related injury during high-altitude exposure. To investigate this, we utilized portable infrared thermographic technology to quantitatively measure changes in the surface temperature of the hands during exposure to increasing levels of normobaric hypoxia in a temperature-controlled high-altitude simulation.

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Objective/background: Up to 25% of patients undergoing elective endovascular aneurysm repair (EVAR) develop acute kidney injury (AKI), which is associated with short and long-term morbidity and mortality. There is no high quality randomised evidence regarding prevention of EVAR related AKI.

Methods: A novel AKI prevention strategy for EVAR was devised, based on best evidence and an expert consensus group.

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