Helicopter evacuations in the Nepalese Himalayas (2016–2017)

According to data from the Government of Nepal, there were 753 002 and 940 218 visitors entering Nepal in 2016 and 2017, respectively. Of these visitors 8.83% in 2016 and 8% in 2017 had come for trekking or mountaineering.1,2 Helicopter evacuations are the best way for rapidly getting patients from remote locations to definitive healthcare,3 and form an important part of search and rescue missions in remote locations all over the world.4,5 Helicopter evacuations in some form have been ongoing in Nepal for more than 35 years. The number of helicopter evacuations is thought to have increased in the recent past. Our study aimed to outline the salient features in trekkers and mountaineers who had to be evacuated by a helicopter and who were seen at the CIWEC hospital and travel medicine centre in Kathmandu, Nepal. The study was a retrospective review of hospital records of all cases of helicopter evacuations brought to the CIWEC hospital between January 2016 and December 2017. Information like age, sex, region of evacuation, altitude of evacuation, patient disposition as well as final diagnosis was retrieved from the hospital records. Data collected were compiled in Microsoft Excel and analysed with R (version 3.6.1) as well as Microsoft Excel. The study received ethical approval from the Nepal Health Research Council (NHRC reference number 443/2018). In the 2 years considered (2016–17), CIWEC hospital received 1354 helicopter evacuations (average 677 cases/year). This accounted for 6.81% of total patients seen at the hospital in the same 2 years. The total number of cases considered amounts to 79.96 evacuations per 100 000 tourists entering Nepal and 905.62 evacuations per 100 000 trekkers/mountaineers (actual rates could be higher as this data was from a single hospital). Most evacuations were conducted in the Everest region (n = 1088, 78.7%) followed by the Annapurna region (7.8%). There were more male (59%) than female (41%) tourists who were evacuated. The mean age of those evacuated was 41.9 years. The average altitude of evacuation was 4391 m (range 380–6600 m), with more than two-thirds (79.54%) of rescues falling in the very high altitude (3500–5800 m) category (Table 1). The largest number of evacuations took place in the fall (October–November; 41.84%) followed by spring (April–May; 34.68%) corresponding to the busiest trekking and climbing seasons in Nepal. About 65% patients had a single final diagnosis whilst the rest had multiple diagnoses. High altitude illnesses were the most common diagnoses amongst the helicopter evacuation cases (56.67%). Of the high altitude illnesses, 31.67% were acute mountain sickness (AMS), 17.04% high altitude pulmonary edema (HAPE) and 16.85% high altitude cerebral edema. Excluding conditions related to high altitude, respiratory problems were the most common (12.10%) followed by gastrointestinal (9.86%), trauma (9.27%) and environmental problems (3.30%, predominantly frostbite). Characteristics of study population and other findings aSoft tissue injuries included strains, sprains, contusions, abrasions and lacerations. Characteristics of study population and other findings aSoft tissue injuries included strains, sprains, contusions, abrasions and lacerations. Amongst respiratory conditions, upper respiratory tract infections (URTI) included 13 cases of influenza. Pneumonia was the final diagnosis for 3.46% of the cases. Some of these patients were initially evacuated for potential HAPE, which were later diagnosed to be pneumonia. There were four cases of acute pulmonary embolism, a life-threatening medical emergency considered one of the differential diagnosis of HAPE with symptoms mimicking HAPE or pneumonia. Amongst the gastro-intestinal conditions encountered, the majority (82.16%) were acute diarrhoea with dehydration. There were also a small number of cases with peptic ulcer disease, some with complications. There were two cases of perforated gastric ulcers, one with peritonitis as well as one case of splenic infarction presenting as severe abdominal pain. There were four cases of myocardial infarction, six cases of arrythmias including atrial fibrillation, four cases of pulmonary embolism, eight cases of deep vein thrombosis, eight cases of acute kidney injury, three cases of seizures, single cases each of septic shock (resulting in mortality), sepsis (non-fatal), vertebral artery dissection, splenic infarct, ischemic stroke, transient ischemic attack as well as diabetic ketonuria; all of them considered medical emergencies regardless of altitude or location. Most cases of trauma were due to falls and involved the extremities. The ankle was involved in most of the cases of fractures with some cases requiring surgery. Other notable cases that were evacuated included three cases of acute urinary retention, four cases of photokeratitis, single cases each of brachial and tibial artery occlusion (potentially limb threatening). Of the 598 (44.31%) evacuated patients who were treated as inpatients, 62.1% were discharged in a day, with an average hospital stay of 1.96 inpatient days (range 1–20 days). Most of the helicopter evacuations (i.e. 96.89%) took place at high altitude (>2500 m) areas of Nepal. This is unsurprising as these are areas that lack road infrastructure and medical facilities. The majority of evacuations (56.67%) were done for altitude illness, and since descent improves symptoms, patients who are brought back rapidly to low altitude areas such as Kathmandu and Pokhara by helicopter, often experience miraculous improvement. The findings in this study also agree with other studies, which point to a wide variety of medical illnesses which trekkers and climbers in Nepal suffer apart from altitude illnesses.6,7 In comparison to the studies of mountain rescues done in other parts of the world, the average age and average altitude of evacuations were both higher.4,5 Studies from the rest of the world point to trauma as the leading cause of helicopter rescue, but in Nepal altitude illnesses comprise a substantially higher proportion, with trauma contributing to 8.09% of cases.4,5 This might be explained by the fact that trekking routes in Nepal ascend to over 5000 m in several routes including the very popular and busy Everest base camp trek (maximum altitude attained 5340 m). Also, most other mountainous regions (except Nepal) offer skiing as a popular activity, which might account for more cases of trauma compared with trekking or hiking. Most regions and countries have a central dispatch system with helicopters integrated into emergency medical services. These involve trained rescuers (medical or non-medical) responding to calls for helicopter rescues, triaging and delivering the sick to appropriate medical facility.4,5 In Nepal, the helicopter rescues are carried out by privately owned helicopter companies usually with no rescuer on board. The call for a helicopter rescue is made by the injured trekkers or their guides usually via insurance companies. Hence, triage at site does not exist, and doctors assessing rescue cases have to rely on information provided by the patients themselves or their attendants regarding their condition. There was substantial increase in the rate of evacuations per 100 000 trekkers and mountaineers. Whilst our study puts the rate of evacuations at 905.62 per 100 000, studies from 1989 and 2008 put the same rate at 75/100 000 and 276/100 000, respectively.8,9 Considering that this study only includes cases received at one hospital in Kathmandu, the actual increase are likely to be higher. The high rate of evacuations can be attributed to increased availability of helicopters as well as evacuation insurance use by trekkers and mountaineers. Helicopter evacuation is the only mode of getting rapid access to definitive healthcare for trekkers and mountaineers in remote settings like the mountains of Nepal. In this study, helicopter evacuation done promptly has likely turned out to be lifesaving in many cases, allowing for patients with severe and acute health problems to be treated at a healthcare facility within hours of onset of illness. Many evacuations are still conducted for preventable or easily treatable problems like AMS, which are not immediately life threatening and have the potential to be managed on the trek or with descent on foot. More needs to be done in terms of raising awareness and educating trekkers, guides, porters and tour operators about the symptoms, prevention and treatment of these conditions. Focus should be on raising awareness about managing conditions like URTI, traveller’s diarrhoea and other minor ailments. Travel health practitioners need to emphasize that trekkers and mountaineers have travel insurance covering the type of activities planned and also covering helicopter evacuations. Improved access to medical care along trekking routes with trained doctors or paramedics, organized and dedicated mountain helicopter emergency response system with trained personnel might help to promote efficient use of the available resources. SD Concept, Data Collection, Analysis, Manuscript preparation; PP Concept, Manuscript preparation and review; RP Data Collection, Analysis, Manuscript review. The authors have declared no conflict of interests. This study did not receive any financial support of funding. Presented as oral presentation at the 12th Asia Pacific Travel Health Conference, 21–24 March 2018, Bangkok, Thailand and XIIth ISMM World Congress on Mountain Medicine, 21–24 November 2018, Kathmandu, Nepal