The bell rang frantically – signal of a clinical emergency. I emerged from the sleeping bag, feeling the crisp air in subzero temperature. It was 6am, soon the sun would rise above Ama Dablam (“Mother’s Necklace”, a stunning 6821m peak) and warm up the land. The horse owner had rung the bell for help, devastated. A yak had attacked his horse during the night. My colleagues and I (two emergency doctors, one generalist, a physician assistant) rushed to the scene – a grass field at the edge of the village. The yak had rammed into the horse with its horns, eviscerating it. It was clear that the horse would not survive, but it was laying on the ground in agony. The gut spilling out of its abdominal wound would attract wild dogs. Time for equine palliative medicine 101. Prince, our Nepali generalist, called his veterinarian friend, who instructed us to give intramuscular morphine at its neck as pain relief. With the help of a few villagers, we wrapped the exposed gut and dressed the wound. We left the horse, covered with a blanket, and his owner to spend its last moments together.
This happened on one of the mornings during my two months as volunteer physician for Himalayan Rescue Association Nepal from September to December 2025, at its aid post in Pheriche village. It is a remote high altitude mountain medicine clinic located at 4,300m altitude, along the Everest Base Camp trek. The aid post provides 24/7 care to both locals and trekkers with the goal of reducing morbidity and mortality in the high altitude region of the Nepali Himalayas. Having served the region seasonally for the past 52 years, the clinic has witnessed the evolution of the local habitat and trekking culture of the region, and has been a significant site for research in high altitude and austere medicine.[1]
Reaching Pheriche from Kathmandu requires a trek of about 12 days or a flight to the airport at Lukla, followed by a five-day hike on foot, or a 10-minute helicopter ride. At 2,840m altitude, Lukla town serves primarily as the starting point for treks in the Everest Region. Although the distance from Lukla to Pheriche is only 40 km, the recommended route takes five days for proper acclimatization. The village is not accessible by motorised vehicles.
Practising equine veterinary medicine might be a bit of an atypical morning for the team. Most of our patients attended for acute altitude illnesses, ie. high altitude cerebral oedema (HACE), high altitude pulmonary oedema (HAPE), acute mountain sickness (AMS), or high altitude headache (HAH). Roughly two-thirds of our patients were Nepali. Among our Nepali patients with acute altitude illnesses, more than half of them were porters.
A common misconception is that local porters and guides are adapted high altitude and are less susceptible to acute altitude illnesses. Indeed, the Sherpa people, an ethnicity which has lived and reproduced at the Nepali highlands for hundreds of generations, had developed genetic adaptation towards hypobaric hypoxia at altitude.[2] For generations, the Sherpa people have been the backbone of climbing expeditions in the Nepali Himalayas, demonstrating their extraordinary resilience at altitude as climbers, climbing guides, and assuming other supporting roles in expeditions. However, most porters nowadays are in fact lowlanders, with no genetic advantage at altitude. With inadequate regulations to protect porters’ wellbeing, they often over-exert themselves carrying heavy loads (some of our patients carried 80kg of supplies for a climbing expedition), ascend too rapidly due to financial pressure (leaving no time for acclimatisation), and do not own proper gear for the journey, putting them at risk of acute altitude illnesses.
A normal peripheral oxygen saturation at 4,300m altitude would be around 80-88%.[3] It would not be uncommon for patients with HAPE to come to us, alert and conscious, albeit breathless, with a pulse oximetry reading of around 60%. Patients with HACE might present to us with signs as subtle as failing tandem gait, or as severe as being unconscious. While we can buy time for the patients with supplementary oxygen and medications (acetazolamide and dexamethasone for HACE; nifedipine SR for HAPE), the definitive treatment is descent at least 1,000m or until symptoms resolve.[4]
The ideal way of descent for emergencies is by helicopter to Lukla or Kathmandu – a life-saving journey but a luxury only for trekkers who can afford the commercial service or are covered by insurance. We often have to negotiate with the helicopter pilot at the helipad outside the village, to evacuate critically ill porters out of goodwill. Otherwise, most of them would have to descend by walking or on the horseback and occasionally on the back of a yak. During blizzards or at night, patients would have to stay hospitalised in our clinic.
Our biggest challenges working in this remote clinic were due to environmental factors. The electrical supply of the clinic was heavily weather-dependent, as it relied on solar power. Consequently, power outages frequently occurred in the mornings after overnight use of oxygen concentrators for patients with HAPE and HACE. There was persistent uncertainty as to whether there would be sufficient power to last through the night. The lack of heating or insulation under freezing temperatures throughout the season compromised patient comfort and led to equipment failure at times.
Working as a high altitude physician for Himalayan Rescue Association Nepal has been a decade-old dream come true for me, an avid mountain lover fascinated by high altitude physiology. My heartfelt wish is for health inequities faced by porters in the region to resolve, and that my journey in mountain medicine will go on.
Dr Joanne Lai
MBBS, FHKCEM, DiMM (Diploma in Mountain Medicine)
References
1. Himalayan Rescue Association Nepal. Accessed April 25, 2026. https://www.himalayanrescue.org/
2. Gilbert-Kawai ET, Milledge JS, Grocott MP, Martin DS. King of the mountains: Tibetan and Sherpa physiological adaptations for life at high altitude. Physiology. 2014 Nov;29(6):388-402.
3. Lorente-Aznar T, Perez-Aguilar G, García-Espot A, Benabarre-Ciria S, Mendia-Gorostidi JL, Dols-Alonso D, Blasco-Romero J. Estimation of arterial oxygen saturation in relation to altitude. Medicina Clínica (English Edition). 2016 Nov 18;147(10):435-40.
4. Luks AM, Beidleman BA, Freer L, Grissom CK, Keyes LE, McIntosh SE, Rodway GW, Schoene RB, Zafren K, Hackett PH. Wilderness medical society clinical practice guidelines for the prevention, diagnosis, and treatment of acute altitude illness: 2024 update. Wilderness & Environmental Medicine. 2024 Mar;35(1_suppl):2S-19S.
