KATHMANDU: With increasing tourism into the thin air of the great mountain ranges of Nepal this Everest Season, the incidences of high altitude illnesses (HAI) are increasing day-by-day. The crux of HAI (in particular AMS, HAPO and HACO) is Hypoxia (lack of oxygen).
Scientific advancements have demonstrated that adverse effects of HAI are potentially preventable. It is imperative for all concerned to enforce and observe preventive measures while climbing in these areas.
The article aims to provide comprehensive instructions on the prevention of adverse effects of high altitude and cold among climbers and trekkers.
- Adverse effects of high altitude
- Medical problems
- Physical performance
- Lowland Vs highland origin climbers
- Climbers at higher risk
- Time of highest risk
- Recognise early symptoms
- Acclimatisation procedure
- Pre-induction medical examination
- First aid
- Other precautions
- Preventing cold’s adverse effects
Adverse effects of high altitude
High altitude is defined as altitude of 2,700 metres (9,000 feet) and more, above mean sea level. The adverse effects on human physiology below this altitude are uncommon, and even if present, are of mild nature. Beyond this altitude, the effects become prominent, causing serious diseases if not adequately tackled. The chances of adverse health effects and interference with physical performance increase with increase in altitude. The environmental conditions of high altitude that cause these adverse physiological processes are the lowered atmospheric pressure of air (commonly referred to as ‘thin air’) and consequent lowered partial pressure of oxygen in the air. This leads to reduction in availability of oxygen in blood, thereby triggering off physiological changes.
Lowered temperature and humidity, increased intensity of sunshine and isolation under monotonous mountain conditions, also contribute to the health hazards.
The health hazards encountered at high altitude are — Acute Mountain Sickness (AMS), High Altitude Pulmonary Oedema (HAPO) and High Altitude Cerebral Oedema (HACO), the latter two being quite serious, often
Even after complete acclimatisation to high altitude and proper training thereafter, the physical efficiency will never be as good as at sea level. The performance level will continue declining with increase in altitude. For every 1,000 metres increase in altitude, the exercise capacity decreases by 10 per cent, till an altitude of 6,300 metres. Thereafter, the decline in exercise capacity is even greater. So, climbers at all levels should make realistic estimates of the physical performance, while planning the climb/logistics.
Lowland Vs highland origin climbers
The physical performance of local native highlanders will be better than the lowlanders, even after full acclimatisation and stay at high altitude. The native highlanders who go down to stay at sea level are also susceptible to develop adverse effects of high altitude on re-entry.
Hence, they should also be properly acclimatised.
Climbers at higher risk
Climbers inducted from low altitude to high altitude areas by air are at higher risk of the adverse effects, vis-a-vis climbers inducted by road, since the body physiology does not get enough time to adapt.
While proper acclimatisation is to be ensured for all climbers, more concerted supervision and control should be exercised on acclimatisation by air-inducted climbers. Persons who have earlier suffered from any adverse effect of high altitude, or having predisposing illnesses are at higher risk and need extra supervision.
Time of highest risk
Most cases of adverse effects of high altitude tend to develop within the first week of induction into high altitude — within the first two to four days, or within a few days of movement ahead to the next higher stage of high altitude. Attention should be paid by climbers at all levels on acclimatisation, during the first week, and specifically during first two to four days, following entry into high altitude, for every stage of acclimatisation.
Recognise early symptoms
Medical personnel and all those concerned should recognise early symptoms of high altitude sicknesses so that it will help provide medical attention to affected person at the earliest.
The early symptoms due to hypoxia are headache, nausea, vomiting (often described as a bad hang-over), mental irritability, loss of appetite, lack of sleep, excessive thirst, palpitations, breathlessness, irritable cough and impaired judgment.
Individual tolerance to hypoxia varies and has no correlation with physical fitness in its ordinary sense. Acclimatisation is the most important preventive measure.
The scientific basis of acclimatisation to high altitude is to gradually allow the body to adapt to the changing oxygen environment, by giving complete rest followed by gradually increasing physical effort, following entry into high altitude. Acclimatisation will be carried out in three stages:
A. First Stage
This will be applicable to individuals who are above 2,700 metres and up to a height of 3,600 metres. The acclimatisation period will be for six days —
i. Day I and II: Rest except for short walk in the nearby area, not involving any climbs
ii. Day III and IV: Walk at slow pace for one-and-half to three kilometres. Avoid steep climbs
iii. Day V and VI: Walk up to five
kilometres (with a gradient not more than 300 metres in five kilometres), at a slow pace
B. Second Stage
(above 3,600 mteres and up to 4,500 metres — Khumjung- Dingboche)
This is carried out for four days —
i. Day I and II: Slow walk for a distance of one-and-a-half to three kilometres. Avoid steep climbs
ii. Day III: Slow walk without equipment up to three kilometres, with a gradient not more than 300 metres
iii. Day IV: Steeper climb of up to 300 metres, without equipment
C. Third Stage
(above 4,500 metres — Dughla- Lobuche- Gorak Shep and Everest Base Camp)
This lasts for four days and is on the same lines as second stage of acclimatisation.
But remember at each stage acclimatisation should be completed.
Pre-induction medical examination
All climbers being inducted into high altitude should undergo a pre-induction medical examination. There should be the doctor’s clinical assessment. It will be the guide’s duty to ensure only medically examined and declared fit by the doctor, are allowed to board the vehicle/aircraft to Lukla.
The best form of management, once a person develops HAPO, is immediate evacuation of the patient to lower
altitude, treatment in the hospital with specific procedures and medications. Till evacuation is possible, the following first aid measures should be undertaken:
• Complete rest. Avoidance of any exertion
• Evacuate to lower altitude, avoiding any exertion
• Oxygen administration, at flow rates of eight litres per minute, using a face mask
• Place the patient in HAPO bag, if available, under doctor’s supervision
• Avoid going too high too fast
• Prompt treatment of respiratory infections is must
• Use of adequate protective clothing and goggles to prevent effects of cold and snow blindness
• Health education to climbers on the ill effects of high altitude
• Avoid excessive alcohol consumption and smoking
• Consume well-cooked, hot, and fresh meals and plenty of warm fluids
• Always maintain a happy and cheerful environment
Preventing cold’s adverse effects
Prevention of adverse effects of cold is far better than cure. All should observe following preventive measures:
Shelter: There should be adequate shelter to protect from cold and wind in living areas, latrines and bathing places. Camps should be sited on the valleys’ slopes, rather than in the trough. Tents should provide adequate protection from wind and snowdrifts. Tents Arctic should be used for accommodation, when available. Use mattress and sleeping bag to keep one warm. Use stoves heating with precaution to prevent fire hazard and carbon monoxide poisoning.
Protective clothing: Loose and warm clothing should be put on in many layers. Outer layer should be impervious to water and wind-proof and the inner layers should be of insulating material like wool. Damp and wet clothing should be changed. Special care should be taken to cover body parts more susceptible to cold’s adverse effects — fingers, hands, feet, toes, nose and ears. The head loses almost 25 to 30 per cent of the total heat from the body surface — so the head should be covered with cap or balaclava.
Gloves /mittens: Wherever authorised, these should be always used. Gloves should be tied at the wrist with a strap, to avoid ingress of snow and water. The sleeves of parka-coat should cover up the ends of the gloves, and strapped with a button/strap, so that snowflakes do not find their way into the gloves. Such strapping should not be too tight.
Boots and socks: Every individual should have at least three pairs of woollen socks so two pairs of socks are worn at a time and one pair is available for change. Socks should be kept in a proper state of repair. Boots should not be tight-fitting, kept soft and water proof, by application of special dubbin. When walking on snow and slush, putties should be used, if available, but they should not be applied too tightly. Avoid sleeping with boots, as it impedes circulation.
Personal hygiene: Feet, hands and face should be inspected each night for signs of cold injury and washed with warm water, dried and smeared with a little Vaseline before sleeping. Sprinkle foot powder before wearing socks to keep feet dry.
Nutrition: Fluid should be taken liberally and food should be nutritious, hot and appetising.
Alcohol and smoking: Alcohol should be avoided, particularly when the individual is likely to be exposed to cold. Moving out in the cold after consuming alcohol should be prohibited. Use of tobacco increases risk of frostbite due to severe narrowing of blood vessels. Smoking should be prohibited once cold injury occurs.
Exercise: Regular moderate exercise is advised to keep up the circulation and body warmth. During prolonged immobility, there should be frequent movement of limbs, fingers and toes.
Handling cold objects: Contact with cold objects, especially metals should be avoided.
Buddy system: Climbers should work in pairs and be taught to watch each other for early signs of any illness and the buddy should draw attention.
Previous history of cold injury. History of previous frostbite increases the risk of fresh injury on a subsequent occasion. Such persons should not be posted to high altitude/cold climate areas.
Climbers at high altitude can be kept in physically and psychologically fit state by proper acclimatisation, good management, leadership, provision of amenities and first aid treatment/quick evacuation. All team leaders have to ensure that the climbers under their command observe preventive measures.
I exhort each and every climber to strive for safety of your buddy and self this Everest season.
Source : thehimalayantimes.com