451,180 research outputs found
Mental Strategies of Elite High Altitude Climbers: Overcoming Adversity on Mount Everest
No full textThe purpose of this study was to explore the mental strategies used by elite Mount Everest climbers to overcome obstacles while ascending and descending the mountain. Individual interviews were carried out with 10 climbers who have successfully reached the summit of Mount Everest. Common strategies of success were identified, as well as factors that created difficulty on the mountain. The themes of focus, mental toughness, short-term goals, drawing on past experience, connecting to one\u27s body, feeling support from other climbers, and belief in personal capacities were seen to have importance in overcoming adversity on the mountain. These results support mental training as an effective tool for overcoming obstacles in the high stress environment of high altitude climbing
eversion versus conventional carotid endarterectomy:Late results of a prospective multicenter randomized trial
No full textA post trek exploratory study on the physical and psychological ill health effects of trekking to Everest base camp following observations by the author
No full textThe purpose of this retrospective study was to understand and test the theory that multiple physical and psychological ill health effects occur when trekking at high altitude to Everest Base Camp (EBC), Nepal. The tour operator, The Adventure Company, agreed to send out 100 questionnaires to clients who had undertaken either the 11 day trek via Tengboche or the 16 day via Goyko Lakes, to EBC. The questionnaires also considered: age, gender, general levels of fitness and previous experience of trekking at altitude. The respondents (n=49) were 53% male (n = 26) and 45% female (n=22) and one unknown. Of the 49 participants, 36 lost weight (p < 0.001) sd ± 2.95 of which 17 were males (p < 0.001) sd ± 2.6 and 19 were females (p <0.001) sd ± 3.3. Altitude sickness was experienced by 38 trekkers or 78% (p < 0.001) using the Lake Louise Score for Acute Mountain Sickness (AMS); 35% (n=17) had mild AMS, 43% (n=21) had severe AMS. The incidence of other conditions was: bacterial infections = (n= 31) or 57% (p < 0.001); general heart rate (n=26) or 55% (p<0.0001); and 71% (n=35) heart rate at night (p <0.0001); low mood = (n=16) or 33% (p< 0.001). The incidence of AMS was higher on reaching 4000m and was consistent with the literature. Other factors identified and consistent with the literature included: significant weight loss; bacterial infections; increase in heart rate in general and at night. Low mood was present during the trek and for some people continued on returning home and has not been well documented in other studies reviewed. Further research on the multiple ill health effects of trekking and how they may be prevented or better managed is needed to reduce risk and aid overall enjoyment
Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia : an ultrasound and MRI study
No full textTranscranial Doppler is a widely used noninvasive technique for assessing cerebral artery blood flow. All previous high altitude studies assessing cerebral blood flow (CBF) in the field that have used Doppler to measure arterial blood velocity have assumed vessel diameter to not alter. Here, we report two studies that demonstrate this is not the case. First, we report the highest recorded study of CBF (7,950 m on Everest) and demonstrate that above 5,300 m, middle cerebral artery (MCA) diameter increases (n=24 at 5,300 m, 14 at 6,400 m, and 5 at 7,950 m). Mean MCA diameter at sea level was 5.30 mm, at 5,300 m was 5.23 mm, at 6,400 m was 6.66 mm, and at 7,950 m was 9.34 mm (P<0.001 for change between 5,300 and 7,950 m). The dilatation at 7,950 m reversed with oxygen. Second, we confirm this dilatation by demonstrating the same effect (and correlating it with ultrasound) during hypoxia (FiO2=12% for 3 hours) in a 3-T magnetic resonance imaging study at sea level (n=7). From these results, we conclude that it cannot be assumed that cerebral artery diameter is constant, especially during alterations of inspired oxygen partial pressure, and that transcranial 2D ultrasound is a technique that can be used at the bedside or in the remote setting to assess MCA caliber
The effect of high-altitude on human skeletal muscle energetics: P-MRS results from the Caudwell Xtreme Everest expedition
No full textMany disease states are associated with regional or systemic hypoxia. The study of healthy individuals exposed to high-altitude hypoxia offers a way to explore hypoxic adaptation without the confounding effects of disease and therapeutic interventions. Using (31)P magnetic resonance spectroscopy and imaging, we investigated skeletal muscle energetics and morphology after exposure to hypobaric hypoxia in seven altitude-naive subjects (trekkers) and seven experienced climbers. The trekkers ascended to 5300 m while the climbers ascended above 7950 m. Before the study, climbers had better mitochondrial function (evidenced by shorter phosphocreatine recovery halftime) than trekkers: 16+/-1 vs. 22+/-2 s (mean +/- SE, p<0.01). Climbers had higher resting [Pi] than trekkers before the expedition and resting [Pi] was raised across both groups on their return (PRE: 2.6+/-0.2 vs. POST: 3.0+/-0.2 mM, p<0.05). There was significant muscle atrophy post-CXE (PRE: 4.7+/-0.2 vs. POST: 4.5+/-0.2 cm(2), p<0.05), yet exercising metabolites were unchanged. These results suggest that, in response to high altitude hypoxia, skeletal muscle function is maintained in humans, despite significant atroph
Green logistics: assessing the economical feasibility of sustainable logistic system in Everest Pharmaceuticals Ltd
No full textThe increased awareness of the detrimental impacts of global climate change has contributed to developing stringent protocols to ensure environmental sustainability across many industries. Adoption of green logistics into core business operations has become mandatory in many parts of the world. Through strategic integration of such practice, industries are able to reduce carbon emissions, enhance resource efficiency, minimize waste production and environmental pollution. This thesis explores the economic feasibility of implementing green logistics practices within the context of Everest Pharmaceuticals Ltd. located in Bangladesh.
Everest Pharmaceuticals Ltd. is a leading pharmaceutical company located in Bangladesh. This company will serve as the case company of this study as it provides a suitable background for this research. To achieve the research aim, three separate research objectives are selected - the identification of current logistic practices of the case company, the development of a framework for establishing green logistics, and the identification of the associated economic benefits and challenges. This qualitative study will interview associated stakeholders, company executives, and environmental experts to formulate the framework in question and assess the economic feasibility. Inductive approach was chosen as this thesis formulated the research outcomes based on the collected data. Semi-structured, open-ended questionnaires will provide the framework for data collection. Purposive sampling will be chosen considering the time and budget allocation.
The findings of this study are expected to provide crucial insights for the commissioner company to develop and implement green logistics into its core business operation. This thesis will also provide theoretical information about the economic feasibility, associated challenges and benefits so that the management of the company can make an informed decision. All of these are expected to help the case company to overcome relevant challenges by fostering Sustainability practices of the company
Caudwell Xtreme Everest expedition
No full textThe Caudwell Xtreme Everest (CXE) expedition involved the detailed study of 222 subjects ascending to 5300 m or higher during the first half of 2007. Following baseline measurements at sea level, 198 trekker-subjects trekked to Everest Base Camp (EBC) following an identical ascent profile. An additional group of 24 investigator-subjects followed a similar ascent to EBC and remained there for the duration of the expedition, with a subgroup of 14 collecting data higher on Everest. This article focuses on published data obtained by the investigator-subjects at extreme altitude (>5500 m). Unique measurements of peak oxygen consumption, middle cerebral artery diameter and blood velocity, and microcirculatory blood flow were made on the South Col (7950 m). Unique arterial blood gas values were obtained from 4 subjects at 8400 m during descent from the summit of Everest. Arterial blood gas and microcirculatory blood flow data are discussed in detail
A randomized study on eversion versus standard carotid endarterectomy: Study design and preliminary results: The Everest Trial
No full textAbstractPurpose: The EVEREST Trial was designed to determine whether the surgical technique influences the durability and complications of carotid endarterectomy (CEA). The current report focuses on the study design and preliminary results. Methods: EVEREST is a randomized multicenter trial. A total of 1353 patients with carotid stenosis requiring surgical treatment were randomly assigned to received standard (n = 675) or eversion (n = 678) CEA. Primary end points included carotid occlusion, major stroke, death, and restenosis rate. Results: The rate of perioperative major stroke and death (1.3 for each study group) and the incidence of early carotid occlusion (0.6% for eversion vs 0.4% for standard) were similar. No significant differences were found between eversion and standard CEA with respect to incidence of perioperative transient ischemic accident, minor stroke, cranial nerve injuries, neck hematoma, myocardial infarction, or surgical defects as detected with intraoperative quality controls. Clamping time was significantly shorter for eversion CEA compared with patch standard procedures (31.7 ± 15.9 vs 34.5 ± 14.4 minutes, p = 0.02). A shunt was inserted in 11% of patients undergoing eversion CEAs and in 16% of patients undergoing standard procedures. Overall 30-day events occurred in 13.3% of the eversion group and in 11.4% of the standard group (p = 0.3). At a mean follow-up of 14.9 months (range, 1 to 38 months), 16 (2.4%) restenoses occurred in the eversion group and 28 (4.1%) occurred in the standard group (odds ratio, 0.56; 95% confidence interval, 0.3 to 1.1; p = 0.08). Conclusion: The preliminary results of the EVEREST Trial suggest that eversion CEA is a safe and rapid procedure with low major complication rates. No significant differences in restenosis rates were observed between eversion and standard CEA at the available follow-up. Longer-term results are necessary to assess whether the eversion technique influences the durability of CEA. (J Vasc Surg 1998;27:595-605.
Physiological responses during ascent to high altitude and the incidence of acute mountain sickness.
No full textAcute mountain sickness (AMS) occurs when there is failure of acclimatisation to high altitude. The aim of this study was to describe the relationship between physiological variables and the incidence of AMS during ascent to 5300 m. A total of 332 lowland-dwelling volunteers followed an identical ascent profile on staggered treks. Self-reported symptoms of AMS were recorded daily using the Lake Louise score (mild 3-4; moderate-severe ≥5), alongside measurements of physiological variables (heart rate, respiratory rate (RR), peripheral oxygen saturation (SpO2 ) and blood pressure) before and after a standardised Xtreme Everest Step-Test (XEST). The overall occurrence of AMS among participants was 73.5% (23.2% mild, 50.3% moderate-severe). There was no difference in gender, age, previous AMS, weight or body mass index between participants who developed AMS and those who did not. Participants who had not previously ascended >5000 m were more likely to get moderate-to-severe AMS. Participants who suffered moderate-to-severe AMS had a lower resting SpO2 at 3500 m (88.5 vs. 89.6%, p = 0.02), while participants who suffered mild or moderate-to-severe AMS had a lower end-exercise SpO2 at 3500 m (82.2 vs. 83.8%, p = 0.027; 81.5 vs. 83.8%, p 5000 m (OR 2.740, p-value 0.003) predicted the development of moderate-to-severe AMS. The Xtreme Everest Step-Test offers a simple, reproducible field test to help predict AMS, albeit with relatively limited predictive precision
Design and conduct of 'Xtreme Alps' : a double-blind, randomised controlled study of the effects of dietary nitrate supplementation on acclimatisation to high altitude
No full textThe study of healthy human volunteers ascending to high altitude provides a robust model of the complex physiological interplay that emulates human adaptation to hypoxaemia in clinical conditions. Nitric oxide (NO) metabolism may play an important role in both adaptation to high altitude and response to hypoxaemia during critical illness at sea level. Circulating nitrate and nitrite concentrations can be augmented by dietary supplementation and this is associated with improved exercise performance and mitochondrial efficiency. We hypothesised that the administration of a dietary substance (beetroot juice) rich in nitrate would improve oxygen efficiency during exercise at high altitude by enhancing tissue microcirculatory blood flow and oxygenation. Furthermore, nitrate supplementation would lead to measurable increases in NO bioactivity throughout the body.
This methodological manuscript describes the design and conduct of the ‘Xtreme Alps’ expedition, a double-blind randomised controlled trial investigating the effects of dietary nitrate supplementation on acclimatisation to hypobaric hypoxia at high altitude in healthy human volunteers. The primary outcome measure was the change in oxygen efficiency during exercise at high altitude between participants allocated to receive nitrate supplementation and those receiving a placebo. A number of secondary measures were recorded, including exercise capacity, peripheral and microcirculatory blood flow and tissue oxygenation.
Results from this study will further elucidate the role of NO in adaption to hypoxaemia and guide clinical trials in critically ill patients. Improved understanding of hypoxaemia in critical illness may provide new therapeutic avenues for interventions that will improve survival in critically ill patients
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