Hypothermia is not the sort of topic you would expect to come across in the temperate climate of Australia, but don’t be fooled. It can even occur in the tropics if the conditions are right (or wrong if you are the victim).
Hypothermia occurs when the body is unable to maintain its core body temperature of 37° Celsius in a cold environment. By definition, hypothermia is a core body temperature of less than 35°C.
While hypothermia can occur secondarily as a result of some medical problems, it is most commonly a primary condition due to exposure to a cold environment.
Although shivering can occur even when the core body temperature is normal, it is one of the body's main intrinsic mechanisms to raise the core body temperature in hypothermia. As the core body temperature slowly falls, the ability to shiver is lost and the body loses the ability to self re-warm.
When am I likely to come across it in the wild?
Hypothermia can occur in any part of Australia given the right circumstances. In the majority of cases it will be the result of a cold environment but there are often other contributing factors that play a significant role including:
Underlying medical conditions or medications that interfere with the ability of the body to regulate temperate: this is a major issue in the extremes of age where temperature self- regulatory mechanisms are limited;
Injury or trauma resulting in immobility: loss of muscle activity that generates warmth;
Ingestion of alcohol or illicit drugs resulting in reckless behaviour (running around naked in the cold) or in prolonged immobility (lying unconscious in the wet grass).
How should I treat these symptoms?
- Remove any wet clothes and replace them with dry ones;
- Seek shelter from the wind and rain and avoid further exposure to cold;
- Warm, sweet drinks: avoid alcohol or caffeinated drinks;
- Place in insulating blanket or pre-warmed sleeping bag with another person;
- If available, apply hot water bottles or commercial heat packs to neck, chest and armpits (be very careful with the groin are because of risks of a burn);
- Allow them to shiver – this is a very effective intrinsic rewarming mechanism;
- Once mildly hypothermic victims are well-hydrated, they can be walked out to safety;
- Moderate and severely hypothermic victims require urgent evacuation and hospital care;
- Severely hypothermic victims need to be kept in the horizontal position and handled gently;
- Only administer CPR if you have the appropriate training and there is no pulse after feeling the carotid artery for two minutes.
Words_Dr Sean Rothwell