The Air Force has been struggling since 2008 to determine why its pilots have suffered relatively rare but repeated “physiological events” involving hypoxia-like symptoms while flying the F-22s — about two dozen of them out of thousands of training missions flown. Hypoxia occurs when the brain does not receive enough oxygen and can cause dizziness, confusion, poor judgment and inattentiveness, according to the National Institutes of Health. For debt consolidation go to www.consolidationdeal.com.au
Measuring specific, exercise-related responses can help physicians determine who may be more at risk for severe high altitude illness (SHAI), according to a study conducted by researchers in France. The researchers also found that taking acetazolamide (ACZ), a drug frequently prescribed to prevent altitude illness, can reduce some of the risk factors associated with SHAI.
The findings were published online ahead of the print edition of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.
The three exercise-related factors identified by the researchers include oxygen desaturation at exercise (Sae), hypoxic cardiac response at exercise (HCRe) and hypoxic ventilatory response at exercise (HVRe). Sae measures the amount of oxygen that is in the blood during exercise; HCRe measures the heart’s response to exercise in a hypoxic, or low oxygen, setting, and HVRe refers to respiratory changes (notably rapid breathing) that occur during exercise in a hypoxic setting.
The researchers measured these parameters in controlled, hypoxic conditions in a lab setting that mimicked high-altitude conditions.
“These results suggest that HCRe, HVRe and substantial decreases in Sae are independent risk factors of SHAI, and that decreases in Sae and HVRe can be used to accurately predict the risk of developing SHAI,” said Jean-Paul Richalet, MD, PhD, a professor of physiology at Université Paris 13.
“To date, this is the largest epidemiological study of subjects exposed to high altitude-related illness, who were previously evaluated for their responses to hypoxia,” he added.
The researchers collected data from 1,326 men and women who were seen prior to high-altitude excursions, which included at least 3 days above 4,000 meters with overnight sleeping above 3,500 meters. Study participants were asked to complete a questionnaire, providing information about their personal and family medical history, usual physical and mountaineering activity and other factors.
Next, study participants went through a routine hypoxic exercise test, which consisted of four, four-minute phases: rest at normal oxygen levels; rest at hypoxic levels; exercise in hypoxia; and exercise in normal levels of oxygen. During the exercise test, the researchers measured heart rate, breathing and blood oxygen levels.
Following their excursions, study participants were asked to complete a questionnaire to determine if they had experienced any symptoms of high altitude pulmonary edema (HAPE), or swelling of the lung tissue; high altitude cerebral edema (HACE), which refers to swelling of the brain tissue; or severe acute mountain sickness (AMS), which can include a variety of symptoms, including headache, nausea, fatigue and dizziness. Participants were also asked to indicate if they had used ACZ.
Among the 1,326 questionnaire respondents, 318 reported that they had experienced a severe altitude illness during their high-altitude excursion, including 105 who used ACZ and 213 who did not.
Using these results, the researchers were able to identify which factors, reported both before and during the excursions, were associated with SHAI. They were also able to determine the effect of ACZ on the development of SHAI.
“We found that among those who did not use ACZ, factors including young age, female gender, history of migraine, regular physical activity, previous history of severe altitude illness, rapid ascent, HCRe, substantial changes in Sae and HVRe were significantly associated with SHAI,” Dr. Richalet said. “Geographically, the area of Ladakh, India, was associated with a higher risk of SHAI among non-ACZ users.”
In those respondents who used ACZ preventively, young age, female gender, history of migraine, regular physical activity, HCRe, substantial changes in Sae and the Alps were no longer significantly associated with SHAI, Dr. Richalet noted, but Ladakh retained borderline significance. A history of SHAI, rapid ascent and HVRe were still associated with SHAI in those who used ACZ, but the associations were not as strong as those noted in non-ACZ users.
They also found that preventive use of ACZ resulted in a 44 percent reduction in the risk of developing SHAI.
“Although it was not double-blinded and placebo-controlled, this study confirms in a large number of subjects the efficacy of the preventive use of ACZ in high-altitude-related illness,” Dr. Richalet said. “These results indicate that preventive use of ACZ may reduce the risk of SHAI in susceptible subjects to the same level as that of non-susceptible subjects.”
The study also linked frequent physical activity to an increased risk of SHAI, a result which Dr. Richalet said supports the common belief among mountaineering experts that increasing the body’s ability to absorb oxygen during exercise is not a predictor of success in high-altitude expeditions.
“Of course, that does not mean that those who visit high altitudes should stop training before an expedition, but they should realize that intense aerobic training is not a protective factor against altitude-related disorders,” he said.
The study is the first to suggest an independent association between the geographical location of ascent and SHAI.
“When adjusted for all other risk factors, especially rate of ascent, one location – Ladakh – remained associated with a higher risk of SHAI in both ACZ and non-ACZ users,” Dr. Richalet said. “No clear explanation, linked to the climate or the difficulty of the terrain, is available, although many informal reports mention the higher risk of this location.”
Dr. Richalet said that although previous episodes of SHAI are still the best predictor of new episodes, results of the study support the use of hypoxic exercise testing, especially in individuals who are planning their first high-altitude excursions.
“Ideally, testing should be aimed both at subjects with no previous experience of high altitude, who therefore lack information about potential risk factors, and those who have experienced severe symptoms in the past, in order to determine if those episodes of SHAI were due to physiological characteristics,” he said. “And of course, during a visit to high altitude regions, it must be emphasized that the best way to avoid severe symptoms is to ascend slowly – less than 400m of altitude difference between two consecutive nights above 3000 meters during the acclimatization period.”
JOINT BASE ELMENDORF-RICHARDSON, Alaska — The nation’s F-22 fighter jets went back into service Wednesday, four months after they were grounded over pilot complaints about a lack of oxygen.
Air Force instructor pilots began flying the stealth jet fighters at six bases across the U.S. This followed a stand-down order, issued in May, and imposed over hypoxia issues reported by at least 12 pilots in the past three years. Hypoxia is when the body does not receive enough oxygen.
“It’s Day One on a road to get our F-22s back in the air and back to their full operational capability,” said Lt. Col. Derek France, 3rd Operational Group commander at Alaska’s Joint Base Elmendorf-Richardson. Forty of the 170 F-22 Raptors are stationed at the Anchorage base.
In the past four months and even before, the aircraft’s oxygen related systems have been the focus of an ongoing safety investigation, France said.
“While they never pinpointed, or have yet to pinpoint, an exact cause of these incidents, they got to a point where they felt that we could, based on risk mitigation, training of air crews and inspection of the aircraft itself, get to a point where we can safely fly again,” he said. “And so that’s the decision, we passed a safety line where senior Air Force officials said that we can go ahead and train again.”
He couldn’t provide additional information about what led to the decision.
“I can’t go into the real details,” France said after the first four Raptors raced down the runway and took off on a training run over Alaska.
“They did a thorough investigation of some of the life support systems in there and some minor modifications within the cockpit to ensure the safety of the pilot,” he said.
Air Force Chief of Staff Gen. Norton Schwartz announced the end of the stand-down order in a statement issued earlier this week.
“We now have enough insight from recent studies and investigations that a return to flight is prudent and appropriate. We’re managing the risks with our aircrews, and we’re continuing to study the F-22′s oxygen systems and collect data to improve its performance,” he said in the statement.
Each $143 million plane was thoroughly inspected before being allowed to fly and will be subject to daily inspections. Pilots will also undergo physiological testing.
The first pilots to fly are instructors, who will then train other pilots once they shake off four months of inactivity.
France said no pilots have expressed concern to him about flying the F-22s, since the investigation has yet to determine the cause for the hypoxia-like symptoms.
“I think they are all fired up and ready to fly,” he said.
France expects it to take a few months before crews are back to pre-stand-down functionality.
The F-22 Raptor was introduced in 2005, and the Air Force said it has flown more than 300 homeland security missions but none in combat.
The fleet is stationed at five other bases besides Alaska: Joint Base Pearl Harbor-Hickam, Hawaii; Joint Base Langley-Eustis, Va.; Nellis Air Force Base, Nev.; Holloman Air Force Base, N.M.; and Tyndall Air Force Base, Fla.
AB Managing Editor: By Michael Popke —
A second man has died following an underwater training accident at a public pool on Staten Island. The New York Daily News reports that 21-year-old off-duty lifeguard Jonathan Proce died Sunday at New York Presbyterian Hospital following an exercise at Lyons Pool last Wednesday in which he and his friend, Bohdan Vitenko, also 21, were practicing underwater breath-holding.
The two were found unconscious and in cardiac arrest in three feet of water at the bottom of the pool; Vitenko died later that day. Two lifeguards have been pulled from their duties after failing to notice Proce and Vitenko, according to The New York Post. Approximately 20 other swimmers were in the pool at the at the time, the paper reports.
Proce was bound for the U.S. Air Force, while Vitenko had dreams of becoming a Navy SEAL. They were regulars at the pool, reportedly participating in a grueling workout routine that included swimming and underwater sit-ups. It is not clear if the men were following an official training program or had developed their own workouts. Either way, the military advises against certain breath-holding exercises or swimming underwater at length to avoid “shallow water blackout,” which can lead to drowning.
According to ShallowWaterBlackoutPrevention.org — an awareness and education site — the condition occurs because of low carbon dioxide and low oxygen (which triggers unconsciousness). Hyperventilation done before breath-holding lowers carbon dioxide abnormally, allowing individuals to hold their breath longer. But the lower carbon dioxide levels rob the body of its built-in mechanism to tell the breath-holder to breathe before going unconscious and taking water into the lungs.
Additionally, “because of the hypoxia, one feels euphoric and empowered to continue breath-holding,” the site states. Unlike regular drowning, where six to eight minutes can elapse before brain damage and death, brain damage and death caused by shallow water blackout can occur within two and a half minutes. More information about shallow water blackout can be found on the Aquatic Safety Research Group’s website.
In 2008, the National Swimming Pool Foundation warned that “anyone who practices competitive, repetitive underwater breath-holding is at risk for shallow water blackout. Once submerged underwater, the swimmer may be hidden from the view of lifeguards by surface glare and ripples/waves on the surface. A series of events is then triggered, including the inhalation of water, possible convulsions and ultimately cardiac arrest and death.”
Dr. Gary Wadler, M.D., the chairman of WADA’s Prohibited List and Methods Subcommittee, says: “There’s tremendous individual variability that makes it hard to predict who will benefit,” .
“In a highly controlled, hospital-level environment, the equipment probably isn’t dangerous,” he says. More worrisome to Wadler are the muscle-heads who will try to cut costs by using homemade setups.
“But if you’re using inferior equipment, there’s a potential to get a severely low intake of oxygen that could result in irreparable damage to the brain.” The lesson here: use the right gear, or risk brain damage or even death.
Here’s a way to get an advantage over the other guys…legally.
Australia Men’s Health Magazine
Luks, Andrew M., Erik R. Swenson.
High Alt. Med. Biol. 12:109–119, 2011.
Pulse oximetry is a valuable, noninvasive, diagnostic tool for the evaluation of ill individuals at high altitude and is also being increasingly used to monitor the well-being of individuals traveling on high altitude expeditions. Although the devices are simple to use, data output may be inaccurate or hard to interpret in certain situations, which could lead to inappropriate clinical decisions. The purpose of this review is to consider such issues in greater detail. After examining the operating principles of pulse oximetry, we describe the available devices and the potential uses of oximetry at high altitude. We then consider the pitfalls of pulse oximetry in this environment and provide recommendations about how to deal with these issues. Device users should recognize that oxygen saturation changes rapidly in response to small changes in oxygen tensions at high altitude and that device accuracy declines with arterial oxygen saturations of less than 80%. The normal oxygen saturation at a given elevation may not be known with certainty and should be viewed as a range of values, rather than a specific number. For these reasons, clinical decisions should not be based on small differences in saturation over time or among individuals. Effort should also be made to minimize factors that cause measurement errors, including cold extremities, excess ambient light, and ill-fitting oximeter probes. Attention to these and other issues will help the users of these devices to apply them in appropriate situations and to minimize erroneous clinical decisions.
Acute Mountain sickness (AMS) is the term given to a number of symptoms that occur after rapid ascent to high altitude. Severe forms may be life threatening because of pulmonary or cerebral oedema. Mild forms of this illness can affect up to 50% of population traveling to altitudes above 12,000 – 14,000 ft.
Symptoms of headache, malaise, and decreased appetite are fairly common amongst individuals traveling to altitudes greater Than 8,000 ft, but these can occur event at lower altitudes.
The mild forms of mountain sickness can usually be treated with rest, hydration, analgesics (eg. ibuprofen), and alcohol avoidance. If you are already experiencing these symptoms do not go to higher altitudes.
Slow progressive step-acclimatisation can help minimising severity of AMS.
Individuals who have already experienced an episode of mountain sickness are at risk for future trips and should seek medical advice.
Severe forms are characterized by severe shortness of breath, cough, severe headache, confusion, or hallucinations. This may progress to coma and death. This is a medical emergency. Immediate descent to lower altitude, administration of oxygen, and medical attention are required.
A very effective method that helps minimising the severity of mountain sickness is pre-acclimation using
hypoxicators for simulated altitude training.
At 8.30am on 11 May 2011 I was privileged to be the first climber for the 2011 season to stand on top of the world. At the same time, I became the 68th Australian in history to summit Mt Everest.
by Paul Hameister
At 8.30am on 11 May I was privileged to be the first climber for the 2011 season to stand on top of the world. At the same time, I became the 68th Australian in history to summit Mt Everest.
However, the reality is that I stood on the shoulders of many others to whom I am sincerely grateful:
· My guide, well-known New Zealander Dean Staples, for whom this was his 7th summit of Everest;
· Our superhuman team of sherpas: Lhakpa (7th summit), Tendi (4th summit) and Gelu (2nd summit);
· The rest of the team at Adventure Consultants who provided infrastructure and support for the entire trip;
· The core Melbourne support group who cared for my wife and kids while I was away (you know who you are);
· My family – my mother (once a mum always a mum, even when your boy is 41) and father – and Dad, who is almost 70, walked heroically with me to Base Camp at the start of the journey; and
· Most importantly, my wife and kids, without whose strength, support and love, the achievement of this dream would not have been possible.
I will save the detailed stories for another time, suffice to say that aside from now being 10kg lighter, still coughing up blood and some frostbite on my face (kisses from Chomolungma herself), I am in relatively good shape.
There was only one other group on the mountain on the 11th – they summitted an hour after us and it included Apa Sherpa, the world record holder for number of summits (this was his 21st summit) – he (at 51 years of age) had the good sense to let us break trail for the night (we left from the South Col for the summit at 11pm).
The following day the weather turned for the worse, but encouraged by our early success a number of groups had a crack and none made the summit and sadly the veteran Japanese climber Takashi Ozaki lost his life from HAPE (he had climbed 6 of the 8000m peaks including Everest previously) on the 12th May on the same route as us.
It has been a very cold season and I have had reports of summit attempts in recent days resulting in bad frostbite injuries that will require amputations. Most groups are still on the mountain at Base Camp waiting for the weather to improve.
The summit itself is the most magical place I have ever been and I will never forget my first sight of those prayer flags fluttering in the wind.
For me though, the 45 days I spent on Everest (and the months of training) will forever be the high watermark of selfishness as a husband and a father in my life and I have an incredibly unique wife to have allowed me this self-indulgence. Now for some rest and some quality family time.
The night I left Melbourne for this journey, my 9-year old daughter Jade made me promise that I would come home safe. I am delighted to still be able to tell my kids that we don’t break promises in our family.
Thankyou to those who donated to Sunrise (refer below email for details if you still feel so inclined). Together we raised around $25,000 for the educational scholarship program for 70-80 at risk young kids in Nepal that will now run for 2011 and 2012 and make a real difference to their lives.
P.S. for those who supported me/Amelia Fuller’s Canteen fundraising efforts on my Denali climb last year (where I was turned back before the summit by bad weather on the same day that Amelia passed away), I did take a part of Amelia’s Canteen t-shirt to the summit of Everest and tied it to the prayer flags up there. I hope that in some way makes up for my non-summit last year.
High Altitude Living Reduces Risk of Dying from Heart Conditions: Low O2 Makes Genes Creating new Blood Vessels
ScienceDaily (Mar. 26, 2011) — Researchers at the University of Colorado School of Medicine in partnership with the Harvard School of Global Health have found that people living at higher altitudes have a lower chance of dying from ischemic heart disease and tend to live longer than others. One of the most comprehensive studies of its kind.
“Lower oxygen levels turn on certain genes and we think those genes may change the way heart muscles function. They may also produce new blood vessels that create new highways for blood flow into the heart.”
“If living in a lower oxygen environment such as in our Colorado mountains helps reduce the risk of dying from heart disease it could help us develop new clinical treatments for those conditions,” said Benjamin Honigman, MD, professor of Emergency Medicine at the CU School of Medicine and director of the Altitude Medicine Clinic.
Another explanation, he said, could be that increased solar radiation at altitude helps the body better synthesize vitamin D which has also been shown to have beneficial effects on the heart and some kinds of cancer.
At the same time, the research showed that altitudes above 4,900 feet were detrimental to those suffering from chronic obstructive pulmonary disease.
Honigman, senior author of the study, along with researchers that included Robert Roach, PhD, director of the School of Medicine’s Altitude Research Center, Deborah Thomas, PhD, a geographer at the University of Colorado Denver and Majid Ezzati of the Harvard School of Global Health, spent four years analyzing death certificates from every county in the U.S. They examined cause-of-death, socio-economic factors and other issues in their research.
“Even modestly lower oxygen levels in people with already impaired breathing and gas exchange may exacerbate hypoxia and pulmonary hypertension [leading to death],” the study said.
Compared to those living near sea-level, the men lived 1.2 to 3.6 years longer and women 0.5 to 2.5 years more.
They found that of the top 20 counties with the highest life expectancy, eleven for men and five for women were located in Colorado and Utah. And each county was at a mean elevation of 5,967 feet above sea level. The men lived between 75.8 and 78.2 years, while women ranged from 80.5 to 82.5 years.
Despite these numbers, the study showed that when socio-economic factors, solar radiation, smoking and pulmonary disease were taken into account, the net effect of altitude on overall life expectancy was negligible.
Still, Honigman said, altitude seems to offer protection against heart disease deaths and may also play a role in cancer development.
“We want to now look at these diseases in a more focused way so we can see the mechanisms behind hypoxia and why they affect the body the way they do,” Honigman said. “This is a public health issue in Colorado and the mountain West. We have more than 700,000 people living at over 7,000 feet above sea level. Does living at altitude change the way a disease progresses? Does it have health effects that we should be investigating? Ultimately, we hope this research will help people lead healthier lives.”
Colorado, the highest state in the nation, is also the leanest state, the fittest state, has the fewest deaths from heart disease and a lower incidence of colon and lung cancer compared to others.
* Heart Disease
* Diseases and Conditions
* Chronic Illness * Coronary heart disease
* Gas exchange
* Oily fish
* Emphysema * Cholesterol
* Stroke Prevention
* Lung Disease
Hypoxia/Mountain Medicine Scientist/Clinician:
You have previously been to the International Hypoxia Symposia or one of our sister meetings regarding mountain medicine. As a fellow scientist/clinician interested in the effects of hypoxia, we want to inform you of the latest developments regarding the upcoming Hypoxia and Cancer 2011 meeting.
If you interest is in all aspects of Hypoxia, then we think you will find fascinating talks and posters throughout the meeting. If you interests are more in Mountain Medicine, then the Hot Topics in Mountain Medicine and Hot Topics in Hypoxia, plus the many posters on mountain medicine will be important for you.
If you have never been to Hypoxia, ask someone who has. Most will tell you that it is one of the best meetings in the world for making new collaborations, renewing old collaborations, and learning new, intriguing and stimulating ideas to push your research and clinical work ahead. The meeting will be held at the stunning Fairmont Chateau Lake Louise in Alberta, Canada.
Hypoxia 2011 presents you with a great opportunity to network with clinicians and basic scientists with a strong interest and decades of experience studying hypoxia. World experts in hypoxia research don’t miss the International Hypoxia Symposia.
Plenary sessions will include: Hypoxia And Its Role In Cancer Biology; Epigenetics And Cancer; The Impact Of Hypoxia In Cancer Biology And Treatment; Cerebrovascular Regulation In Hypoxia ; Causes, Consequences And Treatment Of Sleep-Induced Periodic Breathing; Hypoxia And The Adrenergic Nervous System; Oxygen And Evolution; Future Directions: Hypoxia.
Invited Speakers will include: Till Acker; Stephen Archer; Keith Burgess; Jerry Dempsey; Joachim Fandrey; Amato Giaccia; Grant Gordon; Alexander Gourine; Jeffrey Graham; Jon Harrison; Zdenko Herceg; Shahrokh Javaheri; Mike Milosevic; Tomasz Owerkowicz; Marc Poulin; Jacques Pouyssegur; Sudarshan Rajagopal; Jean Paul Richalet; Stefano Rimoldi; Mikael Sander; Claudio Sartori; Jay Storz; Erik Swenson; John West
Early registration and abstract submission are open for Hypoxia 2011 through this coming Friday, January 7th 2011.
Free communications will be selected by an international jury from submitted abstracts.
We are very excited to be offering a completely new program on Hypoxia and Cancer for the 2011 meeting. The theme of Hypoxia and Cancer will be presented with our signature approach to integrative and translational medicine and physiology. Many other additional topics will be covered throughout the 5 days in Lake Louise.
See the program highlights here (http://bit.ly/gLuBJP).