OB Approved Hypothermia: What is it, How to treat and prevent it.

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Rogue Beardsman

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Hypothermia



Today I would like to talk about Hypothermia. Hypothermia is the lowering of the body's core temperature to a level where normal brain and muscle functions are impaired. It typically happens when several things occur simultaneously: low temperatures (<40F/4.5C), wet conditions (damp clothes), lack of fuel and hydration (food and water), and physical fatigue. This cascade of problems causes our thermoregulatory system to fail. Below I am going to lay out the stages of hypothermia,type of hypothermia, as well as treatment and prevention. First I would like to share a true story from my past.



Years ago on a camping trip I was caught out in a thunder storm on a hike. I did not prepare for any rain and I ignored the likely possibility of rain during Arizona monsoon season. I failed to make and preparations for any possible emergencies. The hike took longer than I had thought it would and by the time I had reached camp I was soaked down to my skin. My change of clothes was in my truck. Unfortunately my friends had left camp in my truck to re supply our food, water tanks and beer. The sun was starting to set and the temperature was dropping for the mid 60's. Our fire ring was now a puddle of water and mud. I moved some rocks and gathered some firewood and broke it up. I had a fero rod and some dried long grass but everything was soaking wet. I tried and tried to get a fire going as the temperatures dropped with the sun. I had started to shiver so violently that I could hardly coordinate a spark and eventually I gave up all together and sat on a stump until everyone returned to camp. By the time my friends returned 2 hours had passed. As they unloaded the truck with the supplies and joked about how It was unlike me not to have a fire going my friend started to notice that something was off. After talking to me and my unusual responses his first assumption was that I had started the festivities without them and that I was already drunk. He quickly started putting the pieces together and noticed that there was something more serious going on. He saw my wet clothes and shivering and started handing out orders. Blankets over here, get a fire going and some hot water or coffee, get those wet clothes off of him, get him dry and wrap him up. It was a while before I snapped out of my drunk-like daze and didn't really understand what had happened. Hypothermia happened and it could have been completely avoided. Without my friends knowledge and quick actions that camping trip could have gotten much worse for me. That was the first moment that I realized that a outdoor lifestyle required my respect and attention. Months later I enrolled in a Wilderness First Responder course and a year after that I went through a Wilderness EMT course and many other courses and instruction related to hiking, and secluded travel and safety.


*Disclaimer*
Before we go any further please know that I have done my best to provide the most accurate information available. Though I am a Nationally Certified WEMT, it is a hobby of mine and not a working career. Please use this article for information and awareness and seek professional medical help and advice when needed.



Stages of Hypothermia

98.6F (37C)

Physiology:Walking and talking. All systems functioning

Cognition:Mentally sharp, paying attention to details, monitoring our environment, and responding appropriately.

Behavior: Physically coordinated,feeling strong and capable, making appropriate gear and clothing decisions, setting a pace appropriate for the conditions, eating and hydrating properly.



97F (36C)
Physiology:
Brain functions slow.

The thermoregulatory center in the brain, sensing heat loss, will initiate several defensive actions.
It will vasoconstrict and reduce blood flow to the skin, creating an additional thermal layer to prevent further heat loss.
Piloerection occurs. That is when our hairs stand up on end to attempt to create an insulating of dead air space.
The rate of metabolism will increase, burning more glucose to produce heat.

Cognition:
Judgment begins to fail.
We become more focused on the trail in front of us and less aware of the weather and our surroundings.
Enthusiasm wanes and apathy sets in.

Behavior: Protective instincts fade.
We don't make the best gear and clothing decisions. We don't make thee best food and hydration decisions. Our mood and reactions change and we become more withdrawn.



96F (35.5C)
Physiology:
All systems are on full alert, and the body is doing everything possible to rewarm itself from the inside.
Shivering begins as a constant, uncontrollable, fine motor tremor, and is caused by opposing muscle groups acting against each other. Shivering produces heat, but it is wasteful exercise that doesn't produce useful work and interferes with activities that require precision: Lighting a stove, pulling a zipper, swinging and ice axe.
Decreased fine motor skills. We begin to lose dexterity and our speech begins to slur.
Metabolism increases to meet the new fuel demands.

Cognition: Mental abilities are falling rapidly. Decision-making, judgment, and “common sense” begin to fail. Self Preservation instinct are replaced with a “summit or bust” mentality.

Behavior: In the face of changing weather (e.g, Drop in temperature, Increase in wind). We may not take any construction action (.e.g putting on another layer). We may leave clothing or equipment behind.



94F (24.5C)
Physiology:
Shivering is at its maximum, but other systems are slowing.
Metabolism is peaking, but fuel is being burned at such a furious rate(up to five times) that the stores will not last long(4-5 hours, rather than the typical 24) When the stores are used up the shivering will slow and eventually cease.

Cognition: We are not aware of being cold. We believe that we are thinking clearly, but we're not. Simple problem solving is impossible( we can't do basic addition/subtraction). When confronted with obvious problems, we may agree, but don't really care.

Behavior: Coordination fails, tripping and falling begins. We have trouble staying on the trail and easily become lost.
We don't take care of ourselves( if we lose a crampon or a mitten or get snow down our back , we don't do anything about it)
Still, we remain goal- oriented-onward to the top/end

92F (33.3C)
Physiology:
Shivering become intense.

Cognition: Mentally, we are beginning to shut down. We enter a dream-like state where nothing seems real

Behavior: We're unable to walk though we may still be crawling toward the goal. Speech becomes very difficult.

90F (32.3C)
Physiology:
Shivering becomes convulsive and begins to fail. Shivering is violent for a minute, then absent for a minuet. We are running out of fuel and energy and shivering will soon cease.

Cognition: We can still be aroused, and will try to answer questions, but our speech will be slurred, perhaps beyond recognition.

Behavior: Curling and mumbling. We adopt the fetal position( the body's last ditch effort to protect the core and minimize heat loss. As things deteriorate, we become less and less arousable, and as the final glucose stores are burned, our shivering mechanism begins to fail.


86F (30C)
Physiology:
We become unconscious, ashen, and gray.
We enter a “Metabolic Icebox” (essentially suspended animation). All systems have slowed to minimize the consumption of oxygen and sugar.
The blood is 190% thicker than normal, Preventing a palpable pulse.
Heart sounds will be absent.
Respirations will slow to 3-6 per minute and so slow and shallow they may be impossible to detect.
We may appear dead: pulse less and breathless with cold, stiff skin and fixed pupils.
There is an expression for this situation.” a person is not dead until they are warm and dead”

Cognition: We are comatose and unresponsive to verbal or painful stimuli.

Behavior: We initiate no action.
 

Rogue Beardsman

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Types of Hypothermia

Subacute/Mountain/Accidental Hypothermia
This is the most common type of hypothermia, and the condition typically develops over just a few hours.
It is often the result of a mishap (e.g., getting benighted on a winter hike), accident (e.g., broken ankle while ice climbing), or any series of poor decisions that leave a person cold, tired, dehydrated, and hungry.
It follows the classic downward spiral described above.

Chronic Hypothermia
Comes slowly over days or weeks.
It is brought on by the combinations of a old environment and poor nutrition and occurs primarily in the geriatric population.
Older, sedentary people need a much warmer environment ( the thermostat should be close to their age). To save fuel, elderly people turn the thermostat down way too low.
As the elderly cool, their metabolism will not increase enough to meet the demand. As we age, our appetites change and we may not be consuming enough calories to keep warm.
They may not shiver in response to the cold.
Mentally, they may exhibit symptoms similar to dementia.
Once rewarmed, they will return to a normal physical and mental state.

Acute or “Shell” Hypothermia
This is caused by a sudden plunge into cold water(think ice fisherman on thin ice)
The “shell” cools suddenly, impairing muscle function and coordination.
The core temperature remains normal.
Death can occur after an hour or so, not because of deep hypothermia, but rather because the rapid cooling of the muscles prevents the victim from the kind of purposeful movement that allows them to stay afloat – death occurs from drowning.

It is a myth that a person plunged into ice cold water will die within three minutes because of hypothermia- you may drown, but you will not die quickly from hypothermia.


Treatment
For mild to moderate hypothermia ( the patient is still conscious and responsive- their core temperature has not dropped below 92F (33.3C)

  1. Remove the patient fro immediate danger and further exposure.

  2. Create shelter: tent, bivouac, snow cave

  3. Get them dry and keep them dry

  4. Remove their wet clothing, dry them off, and re-insulate them with dry clothing.

  5. Place patient in a hypothermia wrap and protect them from the ground.

  6. If conscious and can safely swallow, feed the patient sickly sweet fluids, such as Jell-O in warm water or warm Gatorade. Have them sip constantly. You cannot give them too much water or sugar. Hypothermia victims cannot digest solids, if unconscious, do not try to feed them orally.

For Severe hypothermia(patient unconscious and likely in the fetal position) Do above, plus:

1.Avoid excessive movement or jarring
2.Give rescue breaths


Do Not Do CPR!

The mydocardium of the heart is very susceptible to fibrillation because of elevated potassium levels surrounding the cells. Bumping or jostling can cause the heart to go into ventricular fibrillation. It is almost impossible to defibrillate a hypothermia patient.


Prevention of Hypothermia

Be prepared for wet, wind, and cold

Wear fabrics that stay warm when wet. Do not wear cotton( cotton is rotten, cotton kills). Cotton loses almost all of its insulating ability when wet.

Get dry and stay dry. It can be difficult to re-warm a damp or wet person, and it can be extremely difficult to keep a damp person warm.

Stay well hydrated

Snack often on quick-burning carbohydrates.

Carry bivouac gear and know how to use it.

Be attentive to yourself, to your companions, and the environment. Pay particular attention to mental- status changes.

Turn around before you get in trouble. This is a difficult point to determine, but there are almost always warning signs.

Someone in the party is moving slowly or complaining of being cold and/or tired.

Weather/route conditions are not what you expected or are changing for the worse.

You fall behind the schedule of your plan for the day.

Someone(anyone) says something like”I don't feel good about this”

If I can get one of my friends to volunteer, I will take step by step pictures on building a Hypothermia Wrap.


Sources:
Wildcare. Franklin R, Hubbell, DO
Emergency Care (12th addition)
And My own personal EMT, WEMT, And WFR notes.
 

Kevigizmo

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Very good article
As a First Responder myself the details here are very clear and useful for those who may not have some medical knowledge, very easy to read and would hopefully assist anyone in recognising the early stages of what could potentially be a life threatening situation

It will vary slightly between countries but the general methods are fairly much the same :)
 

Rogue Beardsman

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Very good article
As a First Responder myself the details here are very clear and useful for those who may not have some medical knowledge, very easy to read and would hopefully assist anyone in recognising the early stages of what could potentially be a life threatening situation

It will vary slightly between countries but the general methods are fairly much the same :)
Thank you! I still use this information all the time when in the outdoors.
Even in Florida sometimes it's good to remember when I'm out fishing and get wet when the temperature is dropping.

https://www.instagram.com/roguebeardsman
 
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Cort

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Awesome write up! One piece of kit I keep in my truck and recommend is the North American Rescue Hypothermia Prevention kit. https://www.narescue.com/nar-hypothermia-prevention-and-management-kit-hpmk

This can be had on ebay and amazon for $25-35 frequently and contains a hooded reflective bag(durable space blanket kind of bag) and an oxygen activated heat blanket that outputs 106 degree heat for 7-10 hours.
 
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64Trvlr

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Excellent information, well presented, clearly written, well done!!
 

egilbe

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If you want a good read on the affects of hypothermia and the cascading effects of poor decision making, read "Where you will find me" by Ty Gagne. Its about what lead to the death of Kate Matrosova on Mt Jefferson in NH. Tragic story.