Monday, November 2, 2020

Monday Medical: Hypothermia

Never as funny IRL as this looks.

Hypothermia is technically anytime your body's core temperature is below 95° F.

Last week, Southern Califrutopia had its first "cool" day of the season. Cool is a relative term.
Hereabouts, it means shorts and a T-shirt aren't cutting it. We only visit snow in the mountains, we don't live in it, and our snow blower is called "the Sun". For some of you in other hardier places, our cool temp would be what you call "summer". YMMV. The greater lessons still apply.

Nonetheless, it wasn't that cold, even here. But my patient was over 60. Strike One. (Big risk factor. Older people, just like kids, don't cope well with thermoregulation, both having less muscle mass to generate heat, and a wonky temp control system. One because it's new, the other because it's worn out and old.)

And it was a perfect day for hypothermia. Low 50s. Overcast, hazy sunshine. Breezy, occasional drizzle. Strike Two.

Because on really cold-@$$ days, (and as I said, that is whatever it is to you, in your area) you bundle up. But 50s is just right for thinking, "Hey, it's just brisk, and I'll be working, not sitting, so I don't need to layer up."

My guy spent the day doing yard work. Six hours non-stop. In a sweatshirt.
Strike Three.

Kids, write this on your hand with a laundry pen: 
Cotton KILLS.

And I mean literally. It holds wet, and keeps it right next to the skin, on days when it's too cold to evaporate and dry off. Great in the desert in summer, but catastrophic for a wet day in fall or winter.
At 32° F., all that moisture next to your skin will freeze, wrapping you in a sheet of ice.

And. Then. You. Will. Die.
Deader-than-canned-tuna dead.
Frostbitten solid frozen toes and fingers and hands and feet and nose and ears dead. 

 Don't believe me. Wrap yourself in a bath sheet or beach towel, and soak it with cold water. Now go stand outside on a windy fall/winter day. 
(Please, come back in before you die, but after the point is driven well home.)
Silk, wool, and high-tech synthetics - like good old fleece - are all a hundred times better (or more) than a soaked cotton t-shirt and faux flannel shirt, plus soaking wet cotton jeans (that feel like frozen iron sheets), all made of 100% cotton.

No points for guessing of what 100% of my guy's sweatshirt was made.

Then, after he was worked out, sweaty, and already more chilled, he came in.
It felt hot inside (because he was part popsicled already). And because it was 20° warmer inside than out. But his internal thermostat was already out of whack. Strike Four.

So, in a genius move, he peeled off his sweatshirt (which had, indeed, become sweaty), and sat in front of a fan to cool off! Strike Five.

Which worked.

He rapidly cooled an already chilly body, after burning most of his calories, and was now sitting inside a cool room which took him to the near border of early hypothermia. Strike Six.

Oh, BTW, that 95° F. body core temp number?
Like scuba diving tables, that was determined by Uncle Sugar's best medical experts, based on the physiological responses of young, fit healthy studs in the Navy SEALs, Army Rangers, etc., with 5% body fat, and resting pulse rates in the 40s and 50s, not by testing the effects on out-of-shape 50+ sedentary adults. So for most people, you can throw that 95° number right out the window, unless you're in BUD/S now, waiting to start Hell Week.

This I where the family's common sense accidentally-on-purpose saved a life. Suddenly Paps was feeling weak, thinking fuzzy, not acting right, couldn't stand, and just didn't seem to be himself.

So they called 9-1-1. They knew something was wrong, just not what, exactly.

To arriving medics, given his age and chief complaints, he could have been a cardiac problem, like a heart attack, or a stroke. That's what they thought they had. Great guesses. But not really the problem.

When he got to me, he was shivering uncontrollably, on and off.
So badly that we couldn't get a temperature under the tongue.
Forehead and ear temps are really more like skin temps, not core temps, most of the time, and this was too big to risk on unreliable methods
Time for the tailpipe temperature: one red thermometer, inserted into the exit.
That's a core temp.

He had severe cardiac arrhythmia (really funky heartbeats), low blood pressure, lack of coordination, confusion, weakness, and moderate near-continuous shivering.

His magic number, on arrival at the E.D.: 96.5° F.

Technically, not the magic less-than-95°-F. number that equals hypothermia.
Reality: given his age, physical condition, and symptoms, he was already well into moderate hypothermia.

We put him in a Bair Hugger. It's like a giant hot blow dryer that attaches to a big air mattress quilt, on top of which you pile a layer or two of warm blankets. Think of it as human air fryer, and you're on the right track. After we peeled him out of everything wet , and left him with just a flimsy (but clean and dry) cotton hospital gown. Within two hours, we'd brought him up to more than 98° measured orally, because he was no longer shivering uncontrollably.

Weakness: gone.
Shivering: gone.
Cardiac arrhythmia: gone.
Confusion: gone.
Blood pressure: normal.

Problem solved.

Wherever you live, environmental concerns are a problem, and unless you're Down Under in Oz now, it's approaching winter, so cold is the default environment.
Zero degrees with a -40 wind chill is bad, but you can get into trouble being just a little wet, a little old, a little out of shape, and a little under-protected.

{BTW, other risk factors are diabetes, thyroid problems, alcohol consumption, other substance/drug use, some Rx medications, and severe trauma. Strike 7, 8, 9, 10, 11,12, if you're keeping score at home.} 
Hypothermia creeps up on people, and they don't notice.
Shivering is an early sign.
Later, you stop shivering, because the internal thermostat in your head is fried, and you're freezing.
You're confused, sounding slurred (as if you were drunk), you're tired, drowsy, can't remember things, and uncoordinated.
You think you're warm or hot, so you start taking warm clothes off.
Your pulse slows, you may pass out, and you feel very cold.

Think Mumbling, Fumbling, Bumbling, Stumbling, and Tumbling.

And if someone doesn't intervene, you'll die, feeling warm and fuzzy on the inside, and being a frozen meat popsicle in reality. Like Jack, in that pic up top.

The treatment is simple: REWARM, rapidly. Get them out of the weather, out of wet clothes, and warm them, inside and out. Hot food, hot drinks, and anything else that you can use, will keep from turning a mild problem (frequently mistaken for other things) into a life-threatening one.

Cody Lundin (the hippy dippy barefoot dude co-starring in Dual Survival all these years, entitled his first survival book 98.6 Degrees - The Art Of Keeping Your @$$ Alive. He's a subject matter expert; it really is that simple. And that hard.

Layer clothes.
Dress warm enough to stay warm and feel warm, but not enough to sweat.

COTTON KILLS. Ditch it. Silk, wool or high-speed synthetics are the way to go.

Wear a hat! 90% of body heat is lost through the skin, and most of that right out your bare head.

Conduction sucks. If you sit on the ground put something between you and cold ground, rocks, snow, etc. (Duh.)

Stay well-hydrated. With WATER, not booze. Caffeine is a diuretic (makes you pee) too, and will dehydrate you. Go for hot, sugary drinks. Without caffeine.

EAT, bubbe. Food makes calories, which you need to generate body heat and muscle movement. Young  healthy military troops in cold weather burn twice the calories you do sitting in a cubicle, and even at 5000/day, they - and you - will still lose weight over time working hard in the cold.

Hot food, high in carbs, protein, and even fat, is healthy in cold weather. Fat has twice the calories of carbs or protein, and you need fat to stay alive at cold temps. Butter, mayo, guac, nuts, nut butter, etc., are all your cold-weather friends.

Like batteries, the heart gets wonky when you're cold. It's fragile, and prone to weird rhythms. Which can turn into cardiac arrest. Handle cold people gently. If the pulse stops, CPR starts.

Warm the core first, then the limbs.

I you see something, do something. The longer you wait, the worse it gets, and the harder it is to fix.

Anything from to bodies in a sleeping bag to building a bonfire, to dunking them in a tub of really warm water or a jacuzzi, can work. Use what you've got, and right away.

Stay frosty, but don't freeze your @$$ off.

That concludes your hypothermia briefing. In six months or so, we'll talk about heat emergencies.


RandyGC said...

Key things I learned as a scout in my youth (mostly from observation):

1. The best way to stay warm and dry is not to get cold and wet. (IOW, don't wait until you feel cold to put on a jacket, don't wait until the downpour hits to put on your rain gear)

2. Wet means Cold, Cold means Dead (reinforced by SERE instructors)

And be aware your personal limits can change. I grew up in Iowa. Was stationed in Hawaii and enjoyed the cool 60 degree mornings of the pre-dawn "winter" mornings in my short sleeved shirt while locals were literally donning parkas.

After 2 years there I attended a school in Alabama in January. Growing up dry 50 degrees was light jacket weather. After 2 years in HI it was down right cold to me and I had to layer up. Acclimation is a thing.

Oneissuevoter said...


T-Rav said...

Aesop, out of curiosity, is there anything to be said for rewarming the body slowly, as opposed to rapidly? Wouldn't doing it too fast run the risk of throwing you into shock?

Note, I say this having no background in medicine or first aid whatsoever.

vanderleun said...

And you were doing to well until

"Hypothermia creeps up on people, and they don't notice.
Shivering is an early sign.
Later, you stop shivering, because the internal thermostat in your head is fried, and you're freezing.
You're confused, sounding slurred (as if you were drunk), you're tired, drowsy, can't remember things, and uncoordinated.
You think you're warm or hot, so you start taking warm clothes off.
Your pulse slows, you may pass out, and you feel very cold."

And now you have to take a PA meeting .

I understand that you want to use a list some times so maybe you make use of the ordered list or the unordered list tags.

Maybe this works out to [if blogger comments takes these html tags]:

[but it doesn't. still the list tags ul li would do some good things]

And now I shall just become another sincere admirer of your skills, you knowledge, and your prose. For real.

vanderleun said...

PS you don't have to approve that commment or this one.

w walker said...

And as with heat become more pre-disposed to failure every time you play and don't pay attention to the signs & symptoms

John said...

Cotton kills. I repeated that mantra so often to the Youth Paramilitary Organization (The one with the bird award) that the boys got tired of it. The other mantra? In winter? Sweat kills.

Layers, layers, layers. And feeling a little cold is far better than feeling a little sweaty.

Mittens are better than gloves.

I love the cold.

TwoDogs said...

Excellent lecture. Thank you.

Jim Horn said...

Thank you! Learned the hard way as a kid. And frostbit toes two years ago. Won't let that happen again!

Howard Brewi said...

I remember a news paper story from when I was a kid about 60 years ago. This couple went sailing one afternoon in May. No secondary means pupulsion and no float plan. They got becalmed and very few people out in boats, cell phones were years away. A clam digger found the boat next morning with two dead bodies. It never got colder than the upper forties.

Jimbo said...

Thank you for this ! perfect timing for the impending New England winter.

Mark said...

Years ago I went to a model train show in the old station in Jersey City, NJ. Not only is it right on the Hudson River, since it doubled as a ferry terminal one side of it was completely OPEN to the river, a fact I didn't realize beforehand. It wasn't especially cold, but it was raining, and I got pretty wet from the parking lot to the show, and it was windy in the station. While walking around I felt like hammered dogshit, and while I hadn't gotten to the point of shivering I realized I was uncomfortably cold and wet, I went back to my car, set the heater on Sahara, and sat there a few minutes until I felt human again. Then drove home, and returned to the show the next day.

Considering I was probably in my 30s, in reasonably good health, I lacked the strikes you outline, but I also had enough sense to realize that things weren't going to improve unless I took some steps to improve them.

Remember everyone: Some of nature is actively TRYING to kill you, the rest just doesn't give a crap whether you live or die. If you want to live, it's on you.

Mark D

Aesop said...

Absolutely. When people get to profound hypothermia, i.e. a core temperature below 90° F. down to the 80s, you want to be very conservative. Rewarming all of them, rather than the core, risks dumping cold, acidotic blood back into core circulation, and sending the heart into fibrillation, and cardiac arrest.
Core first, then limbs.
But that gets into the skill set of hospitals more than individuals or even first responders.

But it's Catch-22, since when you start hitting the room-temperature lows, they're just about dead already.

The takeaway is recognize the problem and intervene long before you or they get that bad off, because the edge of the cliff is different for different people, and sometimes, the edge breaks off behind you before you know it's already too late.
It's easier to not walk through the mine field, than to learn how to do field amputations, right?

Paraphrasing what Randy said in comments, "Don't get into trouble, won't be no trouble".

The ER is where Miracle Max from The Princess Bride works: we can fix the mostly dead. Sometimes.
No one fixes the Completely Dead.
Everyone else needs to get busy with their patient(s) before only Miracle Max will do.
Or else, go through their pockets, and look for loose change.

Robin Datta said...

Some animals are tolerant to complete freezing and thawing which occurs as an adaptation to winter, since small body size, poikilothermy, limited migratory ability and absence of insulating fat, fur or feathers mandate such adaptation. They have proteins that prevent freezing water in their tissues from forming ice crystals that would puncture cell membranes.

Mike_C said...

"No one is dead until they are WARM and dead."

An oft-quoted remark that I picked up from Murray Hamlet, DVM, who spent his career in cold medicine/physiology in Natick, Massachusetts at the Army Research Institute of Environmental Medicine. In other words, weird stuff happens when a person is profoundly chilled. Some just die; others, if warmed carefully and properly, survive, and may even come out without lasting damage. (c.f. children who drown in cold water, but are resuscitated without brain damage even after many minutes of immersion.

One thing I remember from Murray's lectures is that the risk of going into dangerous cardiac arrhythmia (e.g VENTRICULAR fibrillation) goes WAY up when extremely hypothermic, to the point where being badly jostled during transport can do it. Here's a link to a brief article that gives the gist of Murray's talks, which he used to give to all sorts of groups and clubs in the Northeast.

Random amusing fact: at least one study has defined "profound hypothermia" based on some set threshold number, e.g. "XX" degrees. What that number? It turned out that the type of thermometer used in the study had XX as the lowest measureable number. You could have been XX or XX-10 and the instrument would not have known the difference.