As the weather warms up in the UK, we’re all looking forward to more daylight and a gradual increase in temperature. So hypothermia is a distant winter worry… isn’t it?
But what exactly is hypothermia and why is it a concern? Surely we all get a bit shivery and chilly from time to time if we’re out in the elements.
A normal human core temperature is around 37 degrees centigrade. But if it drops below 35 degrees, it becomes a medical emergency.
There are many causes of hypothermia and the list below covers the main ones:
- Unsuitable clothing for cold conditions
- Staying out in the cold for too long
- Immersion/submersion into water
- Wearing wet clothes then becoming cold
- Living in a cold environment and not moving much
- Hypoglycaemia (low blood sugar)
- Trauma and blood loss
Some medical and mental health conditions, or using drugs and alcohol can increase the risk of developing hypothermia, often by impairing judgment. It’s also worth noting that hypothermia isn’t just limited to cold days and conditions because it’s still a risk on a hot day if water is involved. It can also affect the elderly and babies who are immoible in an inadequately heated room for a long period of time.
When our bodies are exposed to cold, up to 90% of the heat lost is through the skin and the rest is through exhalation from our lungs. If the cold exposure is due to being immersed in cold water, we can lose heat up to 25 times faster than being exposed to the same air temperature.
So… are you ready for the science bit?
Our temperature control centre is situated in the hypothalamus in the brain. It maintains body temperature by triggering processes to heat and cool the body.
If we get too cold, we start to shiver as a protective response to generate heat through muscle activity. Our blood vessels also vasoconstrict, or narrow, temporarily to preserve heat.
Normally the heart and liver produce most of your body heat. But if your core body temperature reduces, these organs produce less heat, effectively shutting down to protect brain function.
A low body temperature can slow brain activity, breathing and heart rates, and that’s really important because it means that confusion and fatigue can set in. This adversely affects your ability to process information, understand what’s happening and make intelligent choices to help get to safety.
Recognising the point at which someone being a bit chilly turns into a medical emergency can be tricky, especially if they reach the point of confusion and insist they are fine when they’re really not.
Hypothermia symptoms for adults include:
- A temperature under 35 degrees centigrade.
- Shivering - a good sign that the body is recognising heat loss and reacting. But be wary if they seem to stop shivering as at that point the body is shutting down.
- Slow, shallow breathing
- Slow, weak pulse
- Pale, cold and dry skin - skin and lips may appear blue
- Confusion and memory loss, poor decision making
- Behavioural changes
- Drowsiness or exhaustion
- Slurred speech
- Loss of co-ordination
- Unconscious, possibly without discernible respiratory effort or a pulse.
For infants, you should watch out for:
- Bright red skin that’s cold to touch
- Unusually low energy
Hypothermia is split into mild, moderate and severe categories, measured by temperature ranges. But in our world, even mild hypothermia (under 35 degrees) is a concern as it’s only going to get worse without intervention, even if that’s as simple as putting an extra layer on. Hypothermia can lead to heart arrythmias, cardiac arrest and ultimately death.
There are some simple Do’s and Don’t’s to help treat someone who is hypothermic:
If your hypothermic casualty is unconscious, or has no pulse or sign of breathing, you should start CPR and call for help immediately. It’s worth remembering that you might need to feel for a pulse for up to a minute before starting CPR as the heart rate could be very slow and weak, but still present.
If your casualty requires treatment in hospital to raise their core temperature, this can include warmed IV fluid, controlled heating with warm air blankets, heated and humidified oxygen, peritoneal lavage (internal ‘washing’) of the abdominal cavity.
So, our advice is to look out for each other. If you’re working in a cold environment, or there’s an incident involving immersion or submersion in water (regardless of the air temperature), then hypothermia is a risk.
Carry out regular verbal checks and if you’re concerned, use a tympanic (ear) thermometer to establish the temperature. Always have a plan in place, follow your vessel procedures, and if you’d like to plan and practise some drills, the Red Square Medical team can help.