Location
Erebus Volcano is an extremely photogenic volcano with beautiful and often serene scenery, but it is also a very challenging environment for scientific research. While the weather conditions might come to mind first for those challenges, it is only second to its altitude which is of most concern.
Our working area is in the summit region of Erebus volcano, between Lower Erebus Hut (“LEH”; 3402 m/11,161 feet) and Erebus summit at 3,794 m (12,448 ft), well above the elevation above which high altitude sickness becomes an issue (2,400m/8000 ft). As mountain sickness is related to atmospheric pressures rather than the topographic altitude, it is important to know that atmospheric pressure in Antarctica is actually lower than in equatorial latitudes (at equivalent altitude) and hence, the barometric altitude at Mt Erebus is several 100 meters higher than its topographic altitude (it is 700m at South Pole). Rapid ascent to such high elevation usually leads to some form of altitude sickness.
So, what is high-altitude sickness? Overall, it stands for many symptoms and illnesses that can be mild or severe, and range from annoying (mild headache and nausea, dizziness, fatigue, dehydration, flatulence, inability to sleep at night) to debilitating (severe headache and bronchitis-like symptoms from fluid build-up (edema) in the brain and lungs, loss of coordination, sleep apnea). The latter symptoms require serious medical attention without which high altitude sickness can be fatal. You can find a lot of good information on High Altitude Sickness on Wikipedia and in particular on High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE ). And don’t forget to check out High Altitude Flatus Expulsion (HAFE) ,one of the more entertaining applications of Boyle’s (gas) law that you may use in your next physics essay.
Here is a quick thumbnail sketch of the major issues of Acute Mountain Sickness (AMS). As you reach higher altitude, your ears start popping due to the decreasing atmospheric pressure. This lower atmospheric pressures has three major effects on your lung-functions: (1) It is harder to push oxygen into the blood during inhalation, (2) water has an easier time to escape from your lungs, and (3) more CO2 is expelled from your blood into the air that you exhale. Lack of oxygen in your blood obviously will starve your brain and muscles of oxygen so it is much harder to think or do any exercise. Loss of water from your blood will dehydrate your body with consequences as simple as a little dehydration headache, to difficulties in your kidney to cleanse your blood. The decrease of CO2, in your blood will change its acidity (pH) to more basic values which may cause a series of problems that are not well understood but certainly interfere with kidney functions resulting in more urination than normal, further dehydrating your body. These three changes in blood chemistry trigger a series of responses in your body that cumulatively result in the symptoms of AMS, HAPE or HACE. When ascending rapidly to altitude, symptoms may appear within a few hours, and they can disappear almost immediately when descending to lower altitude, even though full-blown HAPE or HACE don’t go away quite as easily without medical treatment.
How to you remedy or treat AMS? Ascending slowly to altitude is probably the easiest means to avoid the symptoms of AMS in the first place. A slow pace gives the body a chance to slowly adjust to the changing pressures. Secondly, it is important to take it easy and get lots of rest when reaching higher altitude and to drink plenty of fluid so dehydration does not become an issue. Concentrate on breathing regularly and deeply. Some people suggest that pursing your lips during exhalation at altitude can slightly increase the pressure in your lungs which will reduce the effect of high altitude. Some suggest recycling your breath with a re-breather can increase the CO2 in the air you breathe into your lungs, even though that will also decrease the amount of oxygen available to your lungs. Putting patients on oxygen can reduce the symptoms of AMS. There are a number of drugs that help ease symptoms of AMS, In particular Diamox helps by re-acidifying your blood to compensate for the loss of CO2. This also helps regulate one’s breathing, in particular at night when AMS often causes the irregular breathing that is commonly known as sleep apnea or Cheyne Stokes Respiration. Another drug, commonly used is Dexamethasone (”Dex”). This effectively treats the fluid buildup in your lungs and brain. One of the ideas of taking these drugs is to give you a good nights’ rest so your body can better cope with AMS. However, if symptoms get worse and every one of the above cures fail, it is very important to go to lower altitude quickly. And this is not always easy in Antarctica. The weather can turn on you, and then a medical evacuation has to wait until aircraft can fly again (which may take up to a week!).
The USAP is very conservative in dealing with AMS. Everybody going to high altitude (South Pole or Erebus) has to take yet another training course on AMS to become aware of the problems, to recognize symptoms early and to take personal precautions, before it is too late. Everybody going to Erebus has to spend two nights at Fang Glacier (at 2800m elevation) before ascending to LEH which gives your body a chance to adjust at moderate elevations. All high altitude USAP locations are equipped with portable Hyperbaric Chambers (Gamow bag) or you bring your own to your particular location. Gamow bags are basically giant, air-tight duffle bags with a pump and a pressure relief valve. When you get sick from AMS, you get into the bag, zip it up and your buddies pump it up to a higher pressure which simulates a descent to lower altitude, and consequently a decrease in the symptoms of AMS. They keep on pumping until you are better or can be evacuated. Not a good scene, in particular when you are claustrophobic.
Romeo Alpha, Hotel Sierra, and Bravo Tango joined a group of six New Zealand scientists on Erebus, and all of us had some symptoms of AMS, one way or another. Key problems were poor night rest, often flue-like symptoms, shortness of breath. Many of us had headaches, at times debilitating. We regularly measured hemoglobin bound oxygen, pulse, and blood pressure: Oxygen was clearly low in the beginning but built up rather rapidly. Pulse and blood pressure tended to be high for most of the time, some days better some days worse. This all clearly affected our ability to do our work during the whole period of 12 days we were up there, but the work was all done in the end and we ended up bringing our Gamow bags back down unused. It was an effort, but everybody did well.
Greetings from Hubert Staudigel (Hotel Sierra) and the G-439 team.
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