21 November, 2003
Living at High Altitude
Every day should start with a talk about Waste Management! In the most bizarre class we have had yet, I learned about McMurdo’s waste management system. I am actually rather impressed by this system. Considering that approximately 1,000 people pass through the tiny town of McMurdo in the summer months, there is a streamlined system of waste management here. It starts small in the kitchen with bright signs labeled “Food Waste Only” or “Burnables” (Figure 1). From there is branches out into garbage stations with bins for “Aluminum,” “Plastics,” “Glass,” “Computer Debris,” “Biohazard,” “Lab Waste,” “Mixed Paper,” etc.. Finally, outside the buildings are large dumpsters (Figure 2) ranging from “Food Waste” to “Old Clothing” to “Mixed Waste” (construction debris). 100% of the waste generated in Antarctica leaves Antarctica for processing. Large cargo bins (Figure 3) are used to transport waste by cargo ship to Washington state.
All waste generated in the field must be separated in the same manner. This made us thankful that while sorting food yesterday, we tried to minimize packaging materials by repacking items in ziplock bags. All waste that is generated in the field is carried back out – whether it be food, fuel, or human waste.
From “Waste Management School,” we moved onto “High Altitude School.” In this class we learned more about the challenges of working at altitude. Mt. Erebus is 12, 448 feet high (3794 meters), so it poses some unique challenges and risks. While the concentration of oxygen in the air remains the same (21%) at high elevations, the number of individual molecules available in each breath you take decreases (there is lower air pressure at elevation). Because you take in fewer oxygen molecules with each breath at elevation, the rate of diffusion (the transport of molecules across a cell membrane from areas of high concentration to low concentration) decreases between your lungs and red blood cells. This means that your blood is carrying less oxygen, a condition called hypoxia. Acute Mountain Sickness (AMS) is the most frequent illness encountered when working at high altitude. AMS is caused by hypoxia and is characterized by headache, fatigue, shortness of breath, nausea, dizziness, and loss of appetite. Extreme cases may even result in the loss of coordination and a decline in mental status (confusion, irrational behavior or loss of consciousness). The best way to prevent AMS is to rest, eat well, stay well hydrated, and take the time to acclimatize.
In order to better acclimatize, our team will be spending two nights in a camp on the Fang Glacier at approximately 9,000 feet before heading to the top of Erebus. Even with this mandatory stop, we have to take it easy on our way up Erebus. While Erebus is only about 12,000 feet high, the atmosphere at the poles is thinner than at the equator, so the physiological altitude (“feels like” altitude) is closer to 14,000 feet. This is considered Very High elevation (as opposed to Mt. Marcy in the Adirondacks, NY, which would be High Elevation or Mt. Everest which is considered Extreme Elevation).
More severe illness encountered at high elevations include High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE). Both of these conditions involve fluid leakage (in the brain and lungs respectively) and can be fatal if untreated. Severe headache, loss of coordination, vomiting, decreased mental status, shortness of breath at rest, cyanosis (blue tinged lips and nail beds), and a cough with frothy pink fluid are all signs that AMS has progressed to something more severe. The only real treatment for HACE, HAPE, and severe AMS is to descend in elevation. Oxygen and medications help to lessen the symptoms, but an individual in this condition needs medical treatment.
Several of us were left wondering at this point “What if the weather is bad and we can’t get a helicopter flight off of Erebus?” To our relief, we discovered that there is, in fact, a back-up plan in the event that a person suffering from HACE or HAPE is stuck on location and cannot descend. A Gamow Bag is a device that can be used to temporarily simulate lower altitude by increasing air pressure. I had the opportunity to experience this device first hand during our High Altitude Class.
The patient goes into the Gamow bag with a sleeping pad, sleeping bag, book, water bottle, etc. to keep him/her comfortable for the next hour or more (Figure 4). A one way, airtight zipper seals the person into the bag (Figure 5). Our instructor directed our attention to a sealed envelope that you must give to the person as they enter the bag. In the envelope is a razor blade. Once you enter the bag, the bag is pressurized and the zipper only opens from the outside. If two people are at elevation together and one has to go into the Gamow bag, he/she needs to be able to escape should their partner get hurt, pass out, etc. A consideration that few of us thought about before it was pointed out to us!
Before starting the Gamow bag demo, we synchronized two altimeter watches to read 310 m (1000 ft) above sea level for the classroom. Once I was comfortably in the bag, another student used a bellows foot pump to gradually increase air pressure. In no time, I needed to clear my ears and a glance at my altimeter told me that the pressure in the bag had increased as though I had descended 200 m in elevation (Figure 6). A few more minutes and I had “descended” to the equivalent of –165 m and was at a pressure of 0.5 psi (pounds per square inch). The bag was stretched tight (Figure 7) and the relief valves occasionally vented air as it is important to keep the air circulating to flush carbon dioxide out of the bag. For a HACE or HAPE victim, you would increase the pressure to 2 psi and could simulate a descent of 5,000-6,000 feet of elevation.
Once the class had seen how the bag worked, the pressure was slowly decreased and I was unzipped from the bag. While the Gamow bag is not a solution for HACE and HAPE, it can certainly be used in an emergency situation to stabilize a victim until they can be evacuated for medical attention. The demonstration also served as a good reminder to drink plenty of fluids, eat well, and rest the first few days at elevation to minimize the risk of Acute Mountain Sickness (AMS).
Altitude Class was a tough act to follow, but Skidoo Maintenance Class was interesting. We learned how to troubleshoot problems with the two snowmobiles we will be using – the Tundra and the Scandia. I now know how to remove and clean out the carburetor and check the spark plugs. Tomorrow we actually get to test drive the machines out on the sea ice. I can’t wait to head out “Into the Great White” tomorrow!
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