Highlights from ‘To the ends of the earth‘; a day conference on wilderness & expedition medicine. Rural Clinical School, Bunbury, WA, 2nd October, 2010.
You’ve bought the book, but didn’t make it to the conference and now you’re planning your next expedition. Here are the highlights of WA’s first conference on the subject.
Cold injury at high altitude and high latitude. C Curry, UWA.
When Shackleton advertise for expeditioners, he noted that safe return was unlikely. Temperatures in Antarctica drop to -86’C Winds get up to 200 kph. Most deaths on epic journeys in this terrain have been due to exposure. The mamalian dive reflex doesn’t work well in adults. Plunge into water at the North Pole and the following happens: vagus bradycardia, aspiration & drowning; gasp, aspiration and drowning; involuntary hyperventilation, aspiration & drowning; muscle failure & drowning. The record for survival when trapped under the ice is 66 minutes in a 2 year old. It is possible to survive 20 minutes immersion. The chances are improved if you adopt a foetal position and don’t flail your arms. The emphasis has to be on prevention.
At altitude, up mountains, hypoxia is added to cold injury. Hats, gloves, windproof garments of breathable, modern artificial materials & good footwear are essential. High up, bulky, air filled clothing that avoids conduction of body heat. Sherpa porters have better tolerance than westerners. Frequent fatalities on Everest. Camp on spurs to avoid avalanches, but high level crevasses are a further hazard. Cold injury most likely at very high altitude. PaO2 = 28mmHg at summit; barely enough for basal metabolism. There is vasoconstriction, extreme hyperviscosity, and dehydration from hyperventilation. Wind at 20kph can freeze exposed flesh.
- Frostbite is closer to a burn than to diabetic gangrene.
- Climbs in Alaska are tougher than in Ecuador.
Trauma in remote places. I Rogers, UWA.
The standard approach to the emegency management of severe trauma assumes the presence of other staff, equipment and support in an optimal hospital environment. The immediate management of trauma in wilderness settings requires improvisation and lateral thinking.
Special environments result in additional challenges: hot & dry v hot & humid, cold & wet v cold & dry; hyperbaric or high & cold.
Injury rates are lower than expected for expeditions e.g. around 1 in 1000 participant days for major trauma, traumatic deaths being rare.
Wilderness Medical Society defines WM as medicine in a remote geographic environment more than 1hr from definitive meeical care. It is limited by medical gear that can be carried, therefore technology limited or ‘medicine stripped bare’. Examples include disaster relief, Qantas flight over Antarctica, road trauma in rural WA.
- A: airway. endotracheal intubation = gold standard for a definitive airway but requires direc vision & optimal access during procedure. Sunlight & limited access make endotrahceal intubation difficult. laryngoscopes can fail, may be poorly tolerated. Laryngeal mask can be used in some remote settings as substitute. No direct vision needed, better tolerated but does not provide definitive airway. A safety pin has been used to anchor the tongue in order to protect airway.
- B: breathing. self-inflating bag, but bulky and not always available. pocket mask = useful standby. Plastic cannula for conversion of tension pneumothorax to simple pneumothorax.
- C: circulation. iv fluids = best practice, used aggressively. emphasis shifting to permissive hypotension in some settings. fluids essential in battlefield management of blood loss
- D: disability. best practice = cervical immobilisaion with collar & spinal board. down side = difficult intubation risk of aspiration, breathing impairment, pressure sores & discomfort. In remote locations can’t walk & evacuation may be delayed. debate over best rules to apply for clearing C-spine. May be necessary to improvise spinal immobilisation with available materials.
- E: exposure. no imaging available for assessment of injuries. small ultrasound scanners available. may be suited to wilderness settings for FAST scan.
- Others: ketamine used in remote locations, though risk of dissociation; acute management of tension pneumothorax can be life saving, thoug occurrence not common; shoulder dislocation = limiting injury on expedition – practical ways of reduction for remote locations.
Medicine in sacred places; the Kokoda Trail, R Murray, PathWest, UWA.
126 km covered in 10 days at an average temperature of 32’C and 90% humidity. 70% drop in trekkers during 2010 due to plane crash in 2009. Flight in is riskiest part due to flying without instruments.
Infectious diseases background. PNG has a range of high prevalence infections including tuberculosis, HIV/AIDS, malaria, diarrhoeal disease, dengue, influenza and hepatitis A. There is a bit of cholera in Port Moresby. No health centres were in use on the trail route taken.
In 1942 Australian soldiers had to cope with battle injuries, wound infections, diarrhoea, foot problems, dengue, scrub typhus and malaria.
Prevention. In order to prevent infection long sleeves & hats were worn, insect repellent and mosquito nets were used. Antimalarial prophylaxis was taken, mainly doxycycline or atovaquone/proguanil. Dukoral and typhoid vaccines were recommended. Water was treated by several different methods: aquatabs, iodine, ceramic filters. Feet were kept clean and dry.
Treatment. Despite preventive measures there are still problems with tinea pedis and minor trauma e.g. blisters, subungual haematoma. Diarrhoea needs a treatment plan e.g. loperamide for mild diarrhoea; azithromycin for diarrhoea & fever, and azithromycin & metronidazole for diarrhoea and upper gastrointestinal symptoms.
Hyponatraemia. Noted in Kokoda trekkers to to overhydration by drikning too much water. Some believe sports drinks may contribute to this condition. Other views are that drinking to a rule may be cause.
Disaster medicine in remote places – the Maldives. A Robertson, HDWA.
The tsunami hit the Maldives between 9 and 9.30am on 26th December, 2004 killing 81 and leaving 26 missing. This Indian Ocean archipelago of 1200 islands has a population of around 350,000 people. The death toll would have been much higher if the fishing fleet had not been at sea and fewer people were able to swim.
This was the first time Australian civilian disaster reponse teams had been activated. By the time team C from WA arrived 3 days after the tsunami, the immediate trauma surgery had been done. The need was a combination of primary care, disease surveillance, public health assessment, humanitarian assistance (water, food, sanitation & waste disposal) and support to local health teams.
- Strengths: government health teams worked closely, were flexible & less political than ADF teams
- Weaknesses: limited health information impacted on planning, coordination & logistics
- Lessons: central governance needed with military or disaster response expertise; local requirements, transport at destination could be challenging; personnel administration, checklists, disaster response equipment caches; state-based Australian teams, liaison with ADF elements, restrictions on travel
Yogyakarta earthquake, 27th May, 2006. Different type of disaster response, affecting 11 districts and leaving 1.5 million homeless. local hospital increased to 400% occupancy. 12 person primary health care/public health team deployed. 1630 consultations & 730 vaccinations.
Medical challenges in Madagascar. M Reeves, Bunbury
- originally colonised from India and Indonesia, then by Arab traders and Europeans
- climate mainly tropical
- large number of unique plant & animal species; no large predators (cats or wild dogs)
- population = 18 million. In 2005, infant mortality = 76 deaths per 1000 live births. average life expectancy approx 60 years. 50% population aged < 16 yrs. staple diet = rice. Traditional burial practice = double burial.
- habitation overcrowded, traffic chaotic, significant pollution, rapid deforestation due to firewood, logging & cattle grazing. widespread malnutrition. leprosy present but few new cases now according to WHO. poor health infrasructure.
Antarctica – I Lishman, Rural Clinical School, Bunbury.
Medical support to the Australian Antarctic Survey. Under the Antarctic Treaty, Antarctica is a demilitarized zone. Australia is responsible for 40% and has 4 bases, the largest of which are continuously manned. medical support is a long way away, though air access can bring help much faster than when it used to depend on the arrival of shipping.
- abseiling & climbing skills required for getting out of crevasses
- handling dog teams, useful additional skill
- immunosuppression during long stays
- keeping up balanced diet & exercise programme both difficult
- trauma e.g. shoulder dislocation not allowed to stop victim until camp (shelter) set up
- risk of fire & carbon monoxide poisoning due to primus stoves & paraffin lamps
- frost bite – managed as burn, without need for amputation or sympathectomy
Bad Day at the Office; Expedition Stress. TJJ Inglis, PathWest laboratory Medicine WA.
Notes by MicroGnome, 2-OCT-10