Winter is coming...

We have recently seen a dip in temperatures across parts of the UK with the Met Office recording a temperature of -3.6 in Katesbridge (County Down) in September.  This is a good time, therefore, for Dr O’Neil to remind us about being adequately prepared when setting off on our outdoor adventures. 

Basic tips to stay warm outdoors include:

Planing your activity well and planning for the unexpected by, for example, bringing extra layers in case the weather changes. Dress for the weather conditions by wearing appropriate cold weather gear!  Make sure you change out of wet or sweaty clothes as soon as possible, have non-alcoholic warm drinks. Lastly, make sure you’re able to contact help if needed.

Of course prevention is better than cure but would you know how to spot signs of hypothermia and what to do to prevent things getting worse?

The body’s core temperature is tightly regulated in the “thermoneutral zone” between 36.5°C and 37.5°C but by definition hypothermia occurs when core body temperature is less than 35°C.

It can be subdivided into mild (32-35°C), moderate (28-32°C) or severe (< 28°C). The sooner the intervention is made the better and spotting early signs can be key to preventing worsening hypothermia.

The initial signs are unsurprising, between 34°C and 35°C, most people shiver vigorously, usually in all extremities.  As the body temperature drops below 34°C, people may develop altered judgment, amnesia, and difficulty speaking. There may be mood change, especially irritability (which you might expect when out in cold weather) but ask yourself is this a sign of worsening hypothermia! You may notice they are breathing faster than usual. At approximately 33°C, apathy may be seen and an increasing unsteadiness and loss of balance.

It is clearly important to know what to look for in others as the affected individual themselves lose the ability to make clear decisions and judgements. One extreme example of this is “paradoxical undressing”. This is when a severely hypothermic person removes clothing in response to prolonged cold stress!

As the core reaches temperatures of 31°C or below, the body loses its ability to generate heat by shivering and so this protective mechanism may stop. Beware the cold person who is not able to shiver. As the core temperature drops further towards 28 degrees there is an increased risk of collapse and even cardiac arrest.

So what should you do?

If you were in a situation where you found someone who was unresponsive and not breathing, CPR can be lifesaving but you need to get help! Continue CPR until professional help arrives in the form of the ambulance service or a medical team. Much more commonly you will be dealing with mild to moderate hypothermia with the signs and symptoms previously mentioned. Remember this is likely to start with shivering and intervention needs to start then.

Follow these steps:

  1. Create an environment most favourable to reducing further heat loss. This most commonly involves removing wet clothing and getting somewhere warmer! That may mean finding shelter out of cold wind and rain preferably somewhere indoors. If the person can’t be moved indoors, find something for them to rest on to protect them from the cold ground, like a towel or a blanket.
  2. Replace wet gear with dry clothing and add layers such as blankets/aluminium foil sheet or sleeping bags.
  3. Give them a warm non-alcoholic drink and energy food that contains sugar, such as a chocolate bar but only if they can swallow normally.
  4. Initiate active external rewarming with heat packs (eg, hot water bottles, chemical packs) placed under the arms, on the groin, and on the abdomen. Be aware of the risk of causing body surface burns from exuberant active external rewarming. If nothing else is available rescuers may provide skin-to-skin contact to aid rewarming.

Key point: for colder, non-shivering patients, the addition of active warming is indicated as a non-shivering person will not rewarm spontaneously.

Preparation is key to avoiding accidental hypothermia. Appropriate cold weather clothing and survival bags with kit mentioned above are a necessity if walking or climbing in the great (but possibly cold) outdoors.

Written by Dr Ollie O'Neill,

Paediatrican in Sheffield

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