Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance (30 page)

Suddenly my body weight doubled, pulling me down into the snow. I could still see the two climbers ahead, but not the rock on which they were standing. A flickering ring of lights obscured all but my central vision. I felt detached from the scene—as if I were no longer a part of it. My reasoning remained intact, though; I knew I was out of oxygen. A teammate came up behind me, unscrewed my regulator, and attached it to the second tank. My head cleared up instantly, my peripheral vision returned, and strength flowed back into my legs. Oxygen was a wonder drug.

I reached the top of the Triangular Face at the same time as everyone else—an hour after sunrise. The plan had been to arrive there just as the sun was coming up. We had lost an hour of daylight that we should have used climbing the treacherous southeast ridge that leads to the summit. And we had used too much oxygen to get this far. Tanks should have been changed on the ridge, not before. To conserve what we had left, we had to turn our flow rate down to 1.5 liters per minute. With less oxygen, our chemical reactions—needed for thinking, talking, judging—would become less efficient, our bodies would cool, we would move even more slowly. But there was no other choice. It would be far worse, and maybe fatal, to run completely out of oxygen at an even higher altitude.

Only the southeast ridge remained between us and the summit,
1,500 vertical feet higher. The ridge is a long, narrow, crooked seam of rock angling 30° upward and tilting 15° from left to right. After a few minutes’ rest for water and chocolate, we climbed onto the ridge. The world opened below me. Standing on an edge barely 8 feet in width, I looked down on ice-covered mountains. I could see the curvature of the earth. I had climbed into outer space.

Gazing up the ridge toward the summit, we saw more of the same deep snow we had been wading through all night. The ridge would be a lot trickier than the Triangular Face, and we would be doing it with less oxygen. The thought that we were not going to make it was in everyone’s mind, though no one said it. We stepped carefully along the ridge in single file, unroped, mindful that at a lower altitude one unroped climber on our expedition had already taken a fatal plunge. But the slope here was so sheer that a slip would turn into a free fall—impossible for another climber to arrest. A rope would just jerk a second climber off the edge when one would be more than enough.

The snow was knee high at the start of the ridge, but soon we were plowing through waist-high snow so dry and granular that it collapsed back around us as soon as we had passed through, forcing each climber to break his own trail. We were climbing a mountain of sugar. Unable to see my legs, much less my boots, I was walking a crooked line, never quite sure where my feet were. With each step, I tried to feel around with my crampon for firmly packed snow before putting my weight down. After several hours of tentative, measured steps, we had made very little progress. Even more discouraging, the angle of the ridge was increasing, the snow getting deeper. Still, the weather was holding. There was little wind, and except for occasional periods of “fog,” which at this altitude were actually clouds moving past us, visibility was good. I had to wait for the air to clear whenever a cloud came by; otherwise I couldn’t be sure if my next step would be on snow or into thin air.

We were at 28,100 feet—at the buttress of the South Summit, a prominence in the ridge after which the angle lessens. The summit was only 900 vertical feet higher. Under normal snow conditions we could be standing at the top in less than two hours. But we were in snow that now had become chest high. The climb had been grueling—depleting
both our oxygen reserves and our energy reserves. We knew how much oxygen we had left; we could only guess how much energy we had left. It was noon. We calculated that at our current rate of progress we would reach the summit in four or five hours. That would mean, though, that we would have to come down in the dark, most likely exhausted and certainly without oxygen. Decisions aren’t easily made by cold, thirsty, very tired climbers whose brains have been short on oxygen for hours. But a decision had to be made.

The last time we had all been at this altitude we had been thinking a lot more clearly. It was when our plane began its descent into the Kingdom of Nepal. Outside the windows, at eye level, was a massive pyramid of rock piercing a carpet of clouds, alone in a vast, empty space. How could a puny human think he might survive there? Then our plane passed below the clouds, dropping us back into civilization and the myriad mundane details of launching an expedition. We had come to measure Mount Everest for
National Geographic
and, as all climbers want to do, measure ourselves. One step at a time, literally and figuratively, we had worked our way back up to what we had seen from the plane, and now were poised on the precarious triangular edge of that foreboding pyramid. We knew we didn’t belong in this place; no one did. The view from the plane had told us that.

Everest is a giant among the innumerable jagged-edged mountains that intrude into the sky in this part of the world. The Himalayas are young and still growing. The process by which they formed began some 80 million years ago when pieces of the earth’s single gigantic landmass began breaking up and floating out across the ocean. The massive piece, or continental plate, we now call India drifted north and, 30 million years later, collided with the even more massive Asian plate. The leading edge of India was driven under the southern edge of Asia, which began to rise and form “wrinkles.” These wrinkles are now the Himalayan mountain range, stretching for 1,500 miles, 500 miles in width, and containing all the highest mountains in the world. India is still sliding under Asia, so the Himalayas are still rising, at the incredibly rapid rate (for geologists) of about one-half centimeter a
year. We were here to measure this rate, and the dynamics that create it, as precisely as we could, as well as to map Everest and determine its exact height.

It takes tons of equipment to measure centimeters
on
Everest. Our expedition had added laser telescopes, global positioning satellite beacons, and computers to the usual mix of ropes, tents, and climbing gear. Twenty porters were hired and forty yaks were rented to carry our equipment—I needed four yaks for my medical supplies alone. We started at an altitude of 9,000 feet, on the landing strip in the foothills where our supply plane had deposited us, then proceeded on foot through some of the most remote, desolate, and spectacularly beautiful terrain in the world. Narrow, precipitous trails led between ice-covered mountains that would blend into the clouds and then suddenly reappear above them against the brilliant blue sky. Because the land has been steadily uplifting for 50 million years, glacial runoff has carved out deep sheer gorges. These are spanned at dizzying heights by rickety wood-and-rope suspension bridges that sway in the wind as you cross them. The rotted-out floorboards and frayed ropes provide up-close evidence of the power of this hostile environment—and of the absence of any recent maintenance inspection.

We made our way up one side of a mountain, then down the other, and then up the next, gradually making net gains in altitude. Too rapid an advance up the mountain would bring on acute mountain sickness, the most common high-altitude problem encountered by lowlanders. The symptoms—a throbbing headache and nausea—are very similar to a hangover, and the cause is probably the same too: dilation of blood vessels and a shift of fluid into the brain that increases pressure within the skull. In a bar, vessels dilate in response to too much alcohol; on a mountain, it’s in response to too little oxygen. Strong coffee helps the hangover because caffeine stretches blood vessels. For acute mountain sickness, the treatment is to go back down a way, or at least stop going up, until the vessels reequilibrate, which usually takes a day or two. It can be prevented altogether by simply going up slowly, a lesson that skiers learn the hard way when they fly from sea level to a mountain resort and expect to ski the next morning. Some never learn it at all and are left with the mistaken impression
that they can’t tolerate altitude, when in fact all they have to do is go slower.

Our expedition stopped early each afternoon, and wherever we were, crowds of Sherpas formed outside my tent, some coming from more than a day’s walk away to take advantage of the opportunity to see a Western doctor. Though none suffered from acute mountain sickness, there were plenty of other illnesses. The most common complaints were stomach pains, largely due to bad diet, and coughing. Sherpas don’t have chimneys in their huts, so smoke accumulates inside, leading to chronic lung conditions such as emphysema. Women brought their entire families, not wanting to lose the chance to have each of their children examined. I diagnosed one child with pneumonia. Lacking pediatric medications, I crushed antibiotic tablets with a stone, then divided the powder into pediatric doses individually wrapped in toilet paper. There were also a lot of dental problems. One woman had a rotten tooth, which I prepared to extract by giving her a lidocaine injection. Once the tooth was numb, however, the pain went away and the woman believed she was cured. No amount of talking could convince her otherwise; she refused to let me pull the tooth.

I did what I could for everyone I saw and, in the last village we passed through, the people showed their gratitude by placing my stethoscope on a stone altar where it was blessed by the local lama.

We continued to march upward, beyond the villages and trails and onto the Khumbu Glacier, following it to its source—the slope of Mount Everest—where we set up base camp. At 17,500 feet, we were already higher than any point in the contiguous United States yet only at the foot of Everest, with still over 11,000 feet to go. We had done the easy part, climbing 9,000 feet in ten days, a fairly slow rate of ascent. Coming up any faster, however, would have killed us. Though we were all short of breath, tired, and cold, we could now survive at this altitude almost indefinitely. Had we been dropped off here by helicopter, we would all have been dead within a few hours. The ten days had given our bodies the time to acclimatize—to make internal adjustments that compensate for the lack of oxygen.

The air in our atmosphere consists of 21 percent oxygen, whether
at the earth’s surface or at the fringes of outer space. Because air has weight, it presses down on the air below it, creating pressure. The higher up the air is in the atmosphere, the less air there is above it, so the less air pressure. Air at 17,500 feet (base camp on Mount Everest) is under only half the pressure as air at sea level. At 29,000 feet (the summit of Mount Everest) the air pressure is only one-third that at sea level. Lungs depend on that pressure to force air inside. Muscles expand lung walls to create a vacuum that’s filled by air, which rushes in through the trachea and bronchial tubes to inflate the air sacs, or alveoli. When outside pressure drops too low, the air just meanders in and may not reach some of the alveoli at all.

Supplying oxygen to the body depends on getting it from the alveoli into the blood. A network of tiny blood vessels called capillaries surrounds each alveolus like a fine mesh. Both the capillary and the alveolus have very delicate membranes stuck to each other, forming a thin wall. Oxygen moves easily through this wall by a process known as diffusion. Diffusion occurs passively, its speed controlled solely by the difference in pressure between the two sides. Lower pressure in the lungs means a slower passage of oxygen into the blood. Arterial blood—fresh blood leaving the lungs—is normally almost fully saturated with oxygen. Two large arteries in the neck, known as the carotids, bring some of that blood directly to the brain, a voracious consumer of oxygen. Within those arteries are nerve sensors called carotid bodies, which monitor the oxygen content of the blood flowing by. Should the carotid bodies detect any decrease, they send a signal to the ever-vigilant hypothalamus, which reacts by inciting responses to increase the oxygen supply. Lungs expand more widely to create a greater vacuum, thereby reestablishing a more effective differential between themselves and the diminished outside air pressure. The heart pumps faster to absorb and distribute the available oxygen more rapidly.

Deeper breathing and a faster pulse were exactly what I felt at the start of my summit attempt after I shut off my oxygen tank and stepped out of my tent into the air on the South Col. The oxygen saturation in my blood suddenly dropped, probably to around 80 percent. Later, when I ran out of oxygen on the Triangular Face, the air
pressure was lower still and the drop in my oxygen saturation even more precipitous. I was too weak to stand, lost my peripheral vision, and had the sensation of being detached from my body—the effects of oxygen loss on the muscles, eyes, and brain. My saturation then was probably around 70 percent. I was still capable of thinking, a function that cuts off at about 50 percent. Should saturation fall below 30 to 40 percent, unconsciousness and death ensue.

Other than by increasing breathing capacity and speeding up blood flow, the body has no immediate way to reverse an oxygen deficit and certainly no way that will enable it to survive if the drop is rapid or overwhelming, such as in an airplane that suddenly loses cabin pressure or after a helicopter ride from sea level to base camp. However, the body does have a highly effective long-term plan for dealing with gradually decreasing air pressure (up to a certain altitude limit), such as we experienced on our ten-day trek to Everest base camp (the base camp, coincidentally, lies at that limit). The components of the plan are what we call acclimatization.

The process begins a few hours after the hypothalamus realizes that the oxygen deficit is not being fully corrected by the heart and lungs and sends out signals for help to other organs. One of the first signals goes to, of all places, the kidneys. The kidneys act as the body’s sewer system, filtering blood and controlling the discharge of waste products. One waste product over which it does not have control is carbon dioxide, the by-product of respiration, which is eliminated through the lungs. Deeper breathing washes greater amounts of carbon dioxide out of the blood, leaving more room to take in additional oxygen. But carbon dioxide is an acid, and if too much is lost, the blood becomes alkaline, disrupting its chemical reactions. The kidneys can’t stop the release of carbon dioxide, but they can rebalance the blood chemistry by releasing more bicarbonate, an alkaline substance over which they have control. Urination increases until the necessary proportions are restored. The lungs can continue to work hard. Unfortunately, the additional water loss (not to mention the water vapor lost by the lungs) contributes to dehydration.