In August of 2005, the eight members of the CASE Cho Oyu Caudwell Xtreme Expedition met in Kathmandu, Nepal intent on climbing Cho Oyu, the sixth highest mountain on earth (8201m). The team intended to pilot a number of experiments planned for the somewhat more ambitious Caudwell Xtreme expedition to Mt Everest in 2007. Despite its height, Cho Oyu is considered to be the most accessible and technically straightforward of the 8000m peaks, making it an ideal venue for field testing the latest scientific technology. Indeed, we wouldn?t be the first to venture onto the slopes of Cho Oyu for medical research. Dr. Griffith Pugh, the physiologist to the successful 1953 Mt Everest Expedition, set the standard during the British-New Zealand Cho Oyu Expedition of 1952.
After months of planning and hours of last-minute preparation, we gathered together in Nepal on August 27th. We needed three days in Kathmandu in order to perform baseline tests for our research project and negotiate the red tape that had steadily gathered around us. With visa officials and customs officers eventually satisfied, we could spend time getting to know the strong Sherpa team. It was clear from our early tests that the load-carrying wasn?t going to be easy ? someone would need to bear the battery-operated fridge and laptops, while another would need to struggle with a replica of the exercise bicycle used for the 1961 Silver Hut Expedition all the way to our Advanced Base Camp (ABC) at over 5700m. The Sherpas took this all in good humour, laughing loudly as they watched us struggle to VO2 max on the bicycle in the overwhelming humidity of a Kathmandu afternoon. Our route north traced a fitful course along the BudhKosi River, stopping a half dozen times at heavily fortified checkpoints bristling with soldiers armed with automatic weapons. Thankfully, on our return journey six weeks later much had changed, with many posts deserted thanks to a ceasefire agreed with the Maoists in our absence. All eight members of the expedition had interests in high altitude physiology, and despite a wide range of backgrounds that varied from primary care to anaesthesiology and laboratory research, we managed to find a common agenda. These projects were greeted with enormous enthusiasm by both Sherpas and expedition members alike, and allowed us to conduct tests around the clock! These included: a) cardiopulmonary exercise testing (CPX) up to 4900m including both VO2 max and anaerobic threshold testing (AT) in acclimatized participants; b) alveolar air analysis at altitudes up to 6300m, and d) studying the effect of supplemental oxygen on healthy participants during sleep, exercise, and hyperbaric chamber treatment up to 5700m.
Meanwhile, our studies concentrated on looking at the performance of a number of oxygen delivery devices that are seen with increasing frequency at altitude. Some commercial groups on Cho Oyu now provide supplemental oxygen to their clients from altitudes as low as 7100m. However, despite large sums of money being spent on oxygen systems for high altitude mountaineering little has been done to systematically evaluate the efficacy of various commercially available supplementary oxygen systems.
For more than three weeks, data collection occupied most of our waking hours, keeping the ?base camp lassitude? described in the famous ascent of Rum Doodle firmly at bay. Thankfully, our final tests at Advance Base Camp coincided with a sudden improvement in the weather. With cold, clear days appearing regularly, we were able to make sorties to Camp 1 and a little beyond. Freed from our research, the mountaineering came as a welcome relief, allowing us all to concentrate on the simple things like consuming an adequate amount of food and drink and putting one foot safely in front of the other on the hill. The acclimatisation period was soon over and within a week the Sherpas began to make hints about a possible summit attempt.
Without a single moment of time over 8000m between us, we all tried, with various degrees of success, to hide our anxieties. Without any experiments to distract us, time in ABC was beginning to drag. Our only options were to stay at ABC and become increasingly bored, or head up the mountain ? inevitably we chose the latter and fell in line behind our head climbing Sherpa, Nanmgyal. At just over 5 feet in height, Nanmgyal was tiny in comparison to his western charges, but what he lacked in height he made up for in stamina and speed. Surefooted and confident, we would follow him anywhere. Later, burdened with oxygen cylinders and science equipment, he would complete the journey from Camp 3 (7500m) to the summit twice in 24 hours and finish with a charge down to Camp 1 (6300m) with blood samples ready for processing. With help from Nanmgyal and his team of climbing Sherpas, six of us made it to the summit. However, there is someone else who should share a portion of the credit ? the aforementioned Dr. Pugh. His scientific conclusions from the 1952 Cho Oyu expedition have become cornerstones of high altitude mountaineering. Not only did Pugh recognize the importance of supplemental oxygen during sleep and exercise, but he also identified the contribution that proper nutrition and fluid intake make to safe climbing practices at such extremes. Without his advice, we would surely have suffered.
Our last week in the mountains soon became a colourful blur in the memory. Despite a carefully hatched plan to flee from Advanced Base Camp to Kathmandu in record time, we were thwarted by missed lifts and authorities who required extra time. Fortunately, thanks to the combination of exhaustion, hot showers, and an endless stream of food, our disappointment was swiftly overcome. The next day began slowly with the obligatory two-hour queue at the border. Once through customs and over the Friendship Bridge on the border of China and Nepal we were again up to speed, careering along the highway and passing through the rich, fertile valleys of Nepal before finally arriving in Kathmandu in time for an appointment at the Everest Steak House. With ?steak fever? much in evidence, vegetarian objections were swiftly overcome and the team quickly settled down to consuming its own body weight in imported Indian beef steak. Vijay, our medical student, emerged from the shadows to impressively consume the leftovers of four steaks and so ensure that plates were cleared and the expedition?s honour was kept intact.
In addition to a number of important fact-finding trips to the watering holes of Kathmandu, we were able to visit the home of our climbing leader, Nanmgyal Sherpa. Over lunch we reminisced about Cho Oyu with his friends and family and arranged a final reunion with our Sherpa team the following evening. What a night! Traveling from far and wide, the entire group was reunited for a final celebration. As we laughed and shared stories we learned more about our new friends and began to recognise the importance of the Himalayas in their lives.
Our climb of Cho Oyu gave us a wonderful mountaineering adventure and an excellent opportunity to perform our science projects. In addition, it also provided us with something important that is common with many journeys of this nature ? a touching experience that is impossible to fully elucidate but will, nonetheless, remain long-lived in our memories.
George Rodway is an Assistant Professor in University of Utah. He is a section editor of Wilderness and Environmental Medicine and Chair of the WMS Publications Committee.
Jeremy Windsor is an Anesthetist and Intensivist at University College London (UK) and member of Caudwell Xtreme Everest 2007.