Hypothermia Demonstration
Background:
When working in cold conditions in Antarctica there is an increased risk of frostbite and hypothermia, especially if you are outside for a long time or aren’t wearing the right clothing.
Hypothermia occurs when the body experiences chilling that causes its internal (core) temperature to drop to 35°C or less. To measure someone’s core temperature, a rectal thermometer needs to be used. Hypothermia is usually caused either quickly by falling into water, or slowly from being outside for a long time in cold conditions. Someone suffering from hypothermia may show signs of the following:
- Fatigue
- Fits of shivering
- Fear
- Foggy speech
- Funny behaviour
- Falling
- Fainting
To treat hypothermia it is vital to get the body’s core temperature back to normal. To do this, it is important not to warm the person up too quickly from the outside. If you warm the skin quickly, the body automatically sends more blood to the warmed area in order to cool it down. This means blood is taken away from the core of the body and, although the person may be warm on the outside, the critical inside core temperature hasn’t changed. If possible, a person suffering from hypothermia should be warmed slowly using a ‘Bair Hugger’. This machine is like a big hair dryer that fills a plastic bag covering the patient’s body (minus head, arms and legs) with warm air. The Bair Hugger has different temperature settings so the person can be warmed slowly. At the same time, the patient should have a bag of warm (42°C) saline introduced to the body intravenously; this will warm them up from the inside too.
Activity:
To demonstrate why it is important not to heat up a person suffering from hypothermia too quickly from the outside, take some frozen sausages, fry one lot of sausages quickly over a high heat, whilst heating the rest slowly in a pan of water. Cut the sausages open to reveal the fried ones still frozen/cold in the middle and the boiled ones heated more evenly all the way through. Use a thermometer to show the difference in heat distribution throughout the sausages.
Acknowledgements:
ANARE First Aid Manual 6th Edition, Australian Antarctic Division (2002)
Dr Bryan Walpole, Aurora Australis, Voyage 1, Sept/Oct 2007
