Mountaineers measure lowest human blood oxygen levels on record

January 7, 2009

The lowest ever levels of oxygen in humans have been reported in climbers on an expedition led by UCL (University College London) doctors. The world-first measurements of blood oxygen levels in climbers near the top of Mount Everest, published in this week's New England Journal of Medicine (NEJM), could eventually help critical care doctors to re-evaluate treatment strategies in some long-term patients with similarly low levels of blood oxygen.

The Caudwell Xtreme Everest team of climbing doctors made the measurements by taking blood from leg arteries close to the summit of Mount Everest at 8,400 metres above sea-level. The team climbed with oxygen tanks, then removed their masks 20 minutes prior to testing to equilibrate their lungs with the low-oxygen atmosphere. The team were unable to make the measurement on the summit of Everest as conditions were too severe, with temperatures at minus 25 degrees centrigrade and winds above 20 knots. Having descended a short distance from the summit, the doctors removed their gloves, unzipped their down suits and drew blood from the femoral artery in the groin. Blood collected from four team members was then carried back down the mountain to be analysed within two hours at a science laboratory set up at the team's camp at 6,400 metres on Everest.

The purpose of the study was to establish what has long been suspected - that high-altitude climbers have incredibly low levels of oxygen in their blood, which at sea-level would only be seen in patients close to death. The expedition found the average arterial oxygen level to be 3.28 kilopascals or kPa (with the lowest value being 2.55 kPa); the normal value in humans is 12-14 kPa and patients with a level below 8 kPa are considered critically ill. Based on calculations of the expected level of oxygen in the blood, the authors also speculate that accumulation of fluid in the lungs as a result of the high altitude might have contributed to the low oxygen levels.

Caudwell Xtreme Everest expedition leader Dr Mike Grocott, a UCL Senior Lecturer in Critical Care Medicine, said: "By observing healthy individuals at high altitude where oxygen is scarce, we can learn about physiological changes that can improve critical care at the hospital bedside, because low oxygen levels are an almost universal problem in critical care. These extraordinary low levels of oxygen found in high-altitude climbers may cause doctors looking after critically ill patients to revaluate treatment goals in some patients who have been ill for some time and might have adapted to low levels of oxygen in the blood. However, our findings will need further careful evaluation before they can be translated into clinical practice. We hope that ongoing research will eventually lead to better treatments for patients with acute respiratory distress syndrome (ARDS), cystic fibrosis, emphysema, septic shock, 'blue baby' syndrome and other critical illnesses."

Source: University College London

Explore further: Automated measure of nighttime oxygen levels could speed diagnosis of sleep apnea

Related Stories

Automated measure of nighttime oxygen levels could speed diagnosis of sleep apnea

August 7, 2017
Computer analysis of oxygen levels in the blood during sleep could—by itself—provide an easy, relatively inexpensive and sufficiently reliable way to determine which children who snore habitually could benefit from a ...

Researchers discover connection between low oxygen levels and a human gene

September 7, 2017
University of Texas at Arlington researchers have established a link between hypoxia, a condition that reduces the flow of oxygen to tissues, and HOTAIR, a noncoding RNA or molecule that has been implicated in several types ...

ICU patients who survive ARDS may suffer from prolonged post-intensive care syndrome

August 24, 2017
Patients who survive acute respiratory distress syndrome (ARDS) often leave a hospital intensive care unit with debilitating mental, physical, or cognitive problems that may limit their quality of life.

Scientists find new evidence about how to prevent worsening pneumonia

September 5, 2017
Sodium channels in the cells that line the tiny capillaries in our lungs play an important role in keeping those capillaries from leaking and potentially worsening conditions like pneumonia, scientists report.

How a baby's brain prepares for the outside world

September 12, 2017
The developing brain is not merely a downsized version of that of an adult, but is uniquely designed to prepare itself for the external world. It has structures and functions whose sole role is to set up the basic circuits ...

Toward a better definition for acute kidney injury in newborns

August 10, 2017
Each year, thousands of infants in the United States end up in neonatal intensive care units (NICUs) with acute kidney injury (AKI), a condition in which the kidneys falter in performing the critical role of filtering waste ...

Recommended for you

Study shows stress could be just as unhealthy as junk food

October 16, 2017
We all know that a poor diet is unhealthy, but a new BYU study finds that stress may just as harmful to our bodies as a really bad diet.

Childhood poverty, poor support may drive up pregnant woman's biological age

October 16, 2017
Pregnant women who had low socioeconomic status during childhood and who have poor family social support appear to prematurely age on a cellular level, potentially raising the risk for complications, a new study has found.

Blood vessel 'master gene' discovery could lead to treatments for liver disease

October 16, 2017
Scientists have identified a key gene in blood vessels which could provide a new way to assess and potentially treat liver disease.

Chronic inflammation plays critical role in sustained delivery of new muscular dystrophy therapy

October 16, 2017
Macrophages, a type of white blood cell involved in inflammation, readily take up a newly approved medication for Duchenne muscular dystrophy (DMD) and promote its sustained delivery to regenerating muscle fibers long after ...

New study demonstrates importance of studying sleep and eating in tandem

October 13, 2017
A new study from scientists on the Florida campus of The Scripps Research Institute (TSRI) offers important insights into possible links between sleep and hunger—and the benefits of studying the two in tandem. A related ...

'Ridiculously healthy' elderly have the same gut microbiome as healthy 30 year-olds

October 11, 2017
In one of the largest microbiota studies conducted in humans, researchers at Western University, Lawson Health Research Institute and Tianyi Health Science Institute in Zhenjiang, Jiangsu, China have shown a potential link ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.