Xtreme Everest and Siemens Healthineers — going to extremes to understand hypoxia

2017-08-11
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Climbing the world’s highest mountain specifically in order to reduce the oxygen level in one’s body to the lowest level possible — and then analyse what happens — may seem a very strange thing to do. But, it is just one example of the lengths Xtreme Everest project team members and volunteers have gone to, in the pursuit of scientific knowledge. This team of doctors and scientists from University College London and the University of Southampton, along with their associated hospitals and colleagues from Duke University in North Carolina and the UK’s Institute of Sport, Exercise and Health, is studying hypoxia, and 2017 marks the tenth anniversary of their first ascent of Mount Everest.


Hypoxia is, in simple terms, a lack of oxygen reaching tissues in the body. When the blood does not bring them sufficient oxygen, all major organs in the body will begin to malfunction and eventually fail. Hypoxia can occur in a wide range of medical situations; for example, severe infection, heart and lung disease, premature birth and respiratory problems can all induce hypoxia. However, it is perhaps most acute in critical care environments.


Hypoxia is common in intensive care units, and the key aim of Xtreme Everest is to understand more about the pathophysiology of hypoxia and to improve outcomes in those units. The team is doing this through study at both sea level and in natural low oxygen environments, including the summit of Mount Everest. With one in five people likely to spend time in an intensive care unit for some reason, at some point, and around 20 per cent of those people dying, this is work that can change many lives. What is particularly remarkable, however, is the fact that for the past ten years its team members, volunteers and associates have put themselves though some really tough challenges in the name of science. And as a sponsor of two of Xtreme Everest’s studies in Nepal, in 2007 and 2013, Siemens Healthineers (formerly known as Siemens Healthcare) has been right there with them.


Everest — a natural laboratory
High altitude locations are the ideal places to study hypoxia, since the air there has lower levels of oxygen than at sea level (so-called ‘altitude sickness’ is caused by breathing air with reduced levels of oxygen). Nowhere is this more so than the highest peak on Earth, Mount Everest. In fact, nobody climbed Everest without supplementary oxygen until 1978, and scientists believe that if Everest was just a few metres higher it would, indeed, be impossible to climb in this way. In other words, Everest is at the outer limits of human tolerance of low oxygen levels, making it an ideal natural laboratory, albeit a very extreme one.


When Xtreme Everest placed a research team on the summit of Mount Everest in May 2007, they made the first ever measurement of the level of oxygen in human blood at 8,400m, on the balcony of the mountain. The blood gas analysers used in this and subsequent treks were provided by Siemens Healthineers. As a result of their work in 2007, the team’s research revealed how capillaries running through tissue and organs are affected by hypoxia, and how they respond to it. Over 200 volunteers joined the team at base camp, providing crucial data on their adaptations and responses to the changes in oxygen levels. One of those volunteers, Dr Daniel Martin, was found to have the lowest blood oxygen level ever recorded in a human; at 2.55 kilopascals it was 80 per cent below the normal levels of between 12 and 14 kilopascals, but somehow, despite having severe hypoxia with half the threshold normally seen in urgent intensive care admissions, Dr Martin was able to walk and talk quite normally.


It is this type of largely unexplained discrepancy in responses between patients that helps to drive the Xtreme Everest team’s work. Observing somebody adapt to such extreme hypoxia prompted the question, can hospital patients adapt to such an extreme, too? And if so, can they be spared some of the interventions that intensive care unit staff use where hypoxia occurs, but which can be detrimental to some of their patients? Using the RAPIDLab® 348 EX system from Siemens Healthineers, the researchers noted how low oxygen levels affected nitric oxide metabolism, an example of how this portable blood gas analyser, suitable for point-of-care use even on Mount Everest, can facilitate cutting-edge research as well as clinical interventions. The 2007 trek generated much interesting data, including fascinating insights that may ultimately prove very helpful in the treatment of diabetes, with results suggesting possible interventions to limit the progression of insulin resistance to full-blown diabetes1.


Five years later, in 2013, Siemens Healthineers’ products were back in action, this time the RAPIDPoint® 500 blood gas analyser and RAPIDLab® 348EX, as the Xtreme Everest team returned to Nepal to further explore the effects of nitric oxide levels on micro-circulation. They also wanted to find out why Sherpas, native to the Everest region, were able to carry out hard labour despite the high altitude and discovered that this was due to a superior oxygen processing ability, a discovery that was reported even by mainstream news outlets around the world2. This has substantial implications for critical care patients, because the team believes their findings will help clinicians to determine which patients are most at risk from hypoxia in hospitals and ultimately to develop better treatments.


Ten years on …
This year marks the tenth anniversary of the Xtreme Everest’s first ascent of the mountain, and a number of events have been held and are planned to celebrate. The team has been back to Nepal to carry out more research and share its knowledge with the Sherpa community, and in May collaborated with the Royal Society of Medicine to hold a two-day event that explored the research, experiments and knowledge arising from the Xtreme Everest studies.


Looking ahead
The Xtreme Everest treks and studies have generated a wealth of insight that will doubtless lead to ground-breaking treatments and approaches. The team has published new research on hypoxia in connection with cognitive functioning3, skeletal muscle energetics4, oxidative stress1 and other aspects. Yet while the work of Xtreme Everest has been, and continues to be, ground-breaking, there is still much to explore and much to discover. Meanwhile many patients continue to be admitted to intensive care units daily, and to suffer hypoxia that is in some cases life changing, and in other cases fatal.


Hypoxia remains a major challenge in critical care medicine, but thanks to the willingness of Xtreme Everest volunteers to endure extremes of altitude, and the help of their supporters including Siemens Healthineers, the long trek to understanding has at least begun.
 

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