Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance (31 page)

The kidneys have another critical role to play. They (as well as other organs, especially the lungs) release a hormone, erythropoietin,
which travels to the bone marrow, the spongy tissue within the long bones of the arms and legs. Marrow is the factory for red blood cells, the oxygen carriers; erythropoietin stimulates their production. More red cells in the blood means more oxygen transport, but reaching full capacity takes weeks. It would be useful to have a “quick injection system.” For some animals, that system is provided by the spleen, the body’s reservoir of red cells. The spleens of deep-diving sea mammals can be contracted, releasing a reserve supply of red cells into the blood but, as with South Sea pearl divers who were once thought to have the same ability, no evidence currently exists that the phenomenon occurs in mountaineers.

Transporting more oxygen through the blood won’t help if it can’t reach the tissues. Red cells carry oxygen by binding it to an iron-bearing protein pigment called hemoglobin—it’s this iron that makes the blood red. The attachment is made in the lungs when oxygen, under pressure, diffuses across the alveolus and is picked up by the passing red cell. Pressure is also needed to detach the oxygen at its destination so that it can diffuse out of the capillary and into the tissues. The transfer slows as the atmospheric pressure drops, but in response the body begins to manufacture more of an enzyme called 2,3, diphosphoglycerate (2,3,DPG), which weakens the oxygen-hemoglobin link and allows the oxygen to come off with less pressure. The higher the altitude, the more 2,3,DPG is produced, keeping pace with the decreasing pressure and preventing the whole oxygen transfer process from stalling. The tissues themselves do their part to help out: they grow more capillaries, making each cell closer to its oxygen source; they increase the size of their mitochondria, the tiny power plants within each cell in which the oxygen is actually burned; and they modify the enzymes controlling that burning—all to make the most efficient use possible of their decreased allotment of oxygen.

The body uses yet another trick to acclimatize itself, one it learned from the diving mammals. Muscles use a great deal of oxygen, and in emergencies they need a readily available supply. Muscles contain a protein called myoglobin, which is similar to hemoglobin but binds oxygen more loosely. Myoglobin provides an on-site oxygen supply, easily accessible for muscles that require extra energy in a hurry. Human
muscles generally contain only small amounts of myoglobin; diving mammals stock it in large quantities and draw on the oxygen it contains while they are underwater. The storage of myoglobin in human muscle increases dramatically at high altitudes, providing some additional measure of protection against the tenuous air supply.

While our bodies were busy making all these adjustments to life at 17,500 feet, some of which take months or even years to complete, we were busy setting up base camp. Each of us had his or her own tent—on a long, stressful team expedition, a place for solitude becomes essential. There was a cook tent in which the Sherpas prepared our meals and a mess tent in which we ate them. No one could take a meal in his or her tent; we all had to come out and eat together—developing a feeling of camaraderie was as essential as the solitude.

As expedition doctor, my responsibility was to turn an empty tent into a medical facility and be prepared for every contingency. The tent was a domed structure, large enough to stand up in at the center or for two or three people to lie side by side along the diameter. Foam mats on the floor provided insulation from the ice below for patients. To make shelves I stacked empty wooden oxygen crates along the walls. I hung carabiners from the roof support rods to serve as hooks to which I could attach IV bags. My four yakloads of supplies had been off-loaded and unceremoniously dumped on the tent floor.

I had given an enormous amount of thought to these supplies before leaving New York. Whatever I didn’t bring I wouldn’t have and would have no chance of getting. I had to be completely self-contained. Yet weight and bulk were limited; four yaks worth was about the most I could ask for. I had made a list of every injury and disease I might be called upon to treat, from head to toe, from fractured skull to athlete’s foot, then written down every piece of equipment, supply, and medication I would need to treat it—pulse oximeter to stethoscope, fiberglass cast to Band-Aid, cardiac stimulant to hemorrhoid pad. For all the medications, as well as for some of the instruments, I had to consider the effect of nightly freezing and daily thawing. It would be impossible to keep everything warm. Pills seemed safer than liquids and were lighter and less bulky. Each item had to be worth its weight. I brought surgical instruments but not a
cardiac defibrillator. They are heavy and bulky, and any climber needing one was probably going to die anyway.

Even harder than deciding what to bring was deciding how much, particularly for heavy but critical items such as bags of IV fluid. A single climber in shock could easily go through ten bags of the stuff. How many climbers should I be prepared to save? I had to resign myself to the idea that disasters might occur that I would not be equipped to handle.

Once I had compiled my final list (ten typewritten pages), I solicited drug companies and surgical supply houses for “free samples.” I was somewhat uncomfortable doing this since I generally try to ignore medical sales representatives. The conversations usually went something like this:

“I need a lot of pills.”

“How many? I’ve got ten or twenty in my case.”

“I need a thousand.”

When I explained that it was for an expedition to Mount Everest, that some would be used to treat local villagers en route and that the extra would be donated to a local clinic, the response was usually “Wait a minute, I’ll call my district manager.” And they always came through. Virtually all my medical supplies were donations. The entire collection was laid out in my office; my wife and children and I sat on the floor for days, repackaging and labeling each item.

Now I was sitting by myself on the floor of a tent, again taking inventory and checking each package for damage. I was especially anxious about our oxygen cylinders, which had been shipped directly from a factory in Russia; they are illegal in the United States because they are made of only a thin layer of titanium—lightweight but prone to leaking and exploding. Most of the cylinders were earmarked for use high up on the mountain, but I needed to keep some at base camp with my medical supplies. Oxygen would be my drug of choice to treat most of the life-threatening illnesses in this environment.

I had divided all my supplies for transport so that if one of my four yaks wandered away or slipped off a narrow trail, my ability to deliver treatment wouldn’t be severely compromised. Now I methodically regrouped everything according to category and set aside one
complete set of every item I would need to treat every critical condition I might face. This took days. I worked slowly because I was getting out of breath easily and my head wasn’t totally clear. Acclimatization was not yet complete. My body was becoming more efficient at using oxygen, but it would still be slowly deteriorating even when maximally acclimatized. That deterioration is the reason why nobody lives here.

Base camp is the physiological border for the human body. Going any higher now would be fatal. Once we were fully acclimatized, though, we would be able to make brief forays across the border to higher altitudes. Short exposures to even thinner air would serve as a stimulus to push each body defense to its maximum and, though further acclimatization would no longer be possible, they would increase the body’s ability to withstand the deadly environment a little longer. Hence the physiological basis for the climber’s intuitive tactic to “climb high, sleep low”—reach maximum altitude during the day and return to a safer altitude at night. But Everest is too big a mountain for a day trip from base camp. To reach the top we needed outposts along the way: four camps to which we could retreat as we pushed toward the summit. Establishing each camp required bringing supplies up a little at a time from base camp. The expedition’s need to make repeated trips to higher and higher altitudes in order to stock the camps coincides exactly with the body’s need for brief exposure to progressively less and less oxygen.

After four days the medical tent was ready to function—and so were our bodies. We began moving up supplies to build the lower camps, staying overnight, then returning to base. Teams that had been there longer had already progressed much higher. A four-man Indian expedition, which had left base camp several days earlier, was moving up from Camp III at 23,000 feet to Camp IV at 26,000 feet, the camp before the summit. The section of the route they were on crosses a sheer ice face spanned by horizontal ropes anchored in the ice, to which climbers hook their harnesses as they traverse the slope. The attachment prevents a 3,000-foot slide, but any climber who slips will be left dangling from the end of a rope, completely exposed to the ice, wind, and cold. Many teams use oxygen to make the traverse.
The Indians, however, had a very limited supply, which they had already stashed at Camp IV for use on their summit attempt. To further conserve oxygen, they started their traverse late in the morning so that they would spend less time at Camp IV, where they would need to be breathing oxygen all night. Though they had dressed as warmly as they could, their clothes were barely adequate, and they carried no radios. They would soon learn that they had cut their safety margin too thin.

As the day wore on, the temperature fell. Freezing winds swept over the ice, carrying away the climbers’ body heat. At first they felt cold, then painfully cold as their bodies sent progressively more urgent signals to their conscious minds to do something. But midway across the smooth, almost featureless slope to which they were closely attached by a short rope, the climbers had no chance to find shelter quickly. Their body temperatures dropped and they started shivering—aimless muscular bursts that begin in the trunk and arms for the sole purpose of generating heat. The contractions spread to the jaw muscles, and their teeth started chattering. Shivering produces only about as much heat as walking. Vigorous motion of the large muscles of the arms and legs constitutes a far more effective way of combating the cold, especially if the power generated leads the person out of danger.

When heat production can no longer fend off the cold, the body conserves its warmth by constricting blood vessels in the areas that leak the most heat. Hands and feet, noses and ears become pale and cold. The head and neck is another highly exposed area, but the body plays favorites. Despite the heat loss, flow to the head remains high in order to assure an adequate supply of blood to the brain. Scientists have only recently discovered the prioritizing of body parts; mothers, who insist their children wear hats and scarves on the coldest days, have long known it.

With nothing more to put on and no way to block the wind, the four Indian climbers tried to traverse faster along the rope. They were generating heat and moving toward shelter but also burning large amounts of fuel reserves—a process the body can’t sustain for long. The only other protective response humans have against cold is goose bumps—which occur when the tiny muscles attached to hair follicles
contract to straighten our body hairs, creating loft to trap warm air against the skin. It works for the feathers of high-flying birds and the fur of arctic foxes. For humans, with their relative paucity of hair, the mechanism seems almost pathetic.

Our bodies were designed for the tropics and are woefully inadequate to defend against cold. We survive only because of clothing and shelter, making us dependent on brainpower and manual agility. For every 1°F drop in body temperature, cerebral metabolism decreases by 5 percent. Chemical reactions slow. Thinking becomes sluggish, and fine motor dexterity is lost, critically affecting our ability to get out of the very situation that is causing the problem. As we run out of energy to keep the internal fire burning, the cold takes over. Electrical transmission of nerve impulses is delayed, its amplitude reduced. Body parts become numb, limbs lose their coordination, the mind becomes apathetic.

Two of the Indian climbers stopped to rest on the ropes. The other two continued slowly upward. None of them thought to turn around. As their body temperatures dropped below 90°F, they lost even the energy to continue shivering. Once shivering stops, internal temperature drops precipitously and the body quickly spirals downward. Cold muscles lose their elasticity. Lungs can’t expand and limbs stiffen. Muscle activity is reduced, decreasing heat generation still further. Soon the climbers would not be able to move at all.

One of the two climbers resting on the rope had enough presence of mind and enough coordination to take his sleeping bag out of his pack and place it upside down over his head and chest. Because his harness was attached at his waist to the rope in the ice, he couldn’t get the sleeping bag any lower. The other climber just hung from the rope, exhausted. By about 3
A.M
. the climber with the sleeping bag over his head had regained some strength. He was unable to see his teammate in the total darkness but managed to descend to Camp III. There he found a radio and called down to base camp.

When we heard the news, we realized that some members of our team were also at Camp III, having spent the night there after dropping off supplies. We radioed up to Todd Burleson, our expedition leader. He made his way over to the Indian tent and found the exhausted,
hypothermic climber lying there. Todd brought him to our team’s tent, and while he was being warmed and fed, the climber told Todd that just before reaching Camp III he had looked back up the slope and, in the dawn light, saw his teammate dangling from the rope. “His arms were moving, not like from the wind.” He believed he might still be alive.

Before Todd and the other climbers at Camp III could mount a rescue attempt, however, we got information that made such an attempt unnecessary. One of the two Indian climbers who had continued upward descended back to camp this morning. He had reached Camp IV the previous evening. His partner had also reached Camp IV, staggering in some time later. His body temperature was probably above 85°F, for he was still conscious and able to move, but it was also clear that he had exceeded his physical limit. His body defenses had been overwhelmed; he couldn’t summon the energy to produce heat. Without some external heat source to rewarm him, death was inevitable. His temperature continued to drop. When it fell below 85°F he became unconscious, thereby losing any last chance to do something to save himself. His heart was still beating regularly, though only once or twice a minute. Below 80°F the feeble heartbeat became an irregular flutter, and at around 70°F it stopped altogether.