Hypothermia in Trauma Patients

Trauma Patients who Bleed Become Hypovolemic

Hypothermia in Trauma Patients

Always Better. | July 30th 2021

We previously discussed tourniquets and bleeding control but today I wanted to discuss a related topic. One of the first things I noticed when assessing the contents of the MTKN and TKN-MEDIUM trauma kits when I arrived at BFG was that there was no accommodation to address hypothermia.

Most people associate hypothermia (“hypo” = LOW and “thermia” = TEMPERATURE) injuries with environmental exposure such as being out in the cold without proper warm clothing. While correct, this isn’t the type of hypothermia injury we are worried about with trauma patients.

Trauma patients who bleed become hypovolemic (there is “hypo” again – “hypo” = LOW and “volemic” = VOLUME), in other words, they get low blood pressure because well… they are losing blood. The loss of blood, and we will be discussing blood loss in a later post, causes all sorts of physiological issues that can lead to death. For now, let’s keep it simple in accepting that BLEEDING IS BAD. We want to stop it as quickly as possible and then we want to treat the patient for the after effects.

While it is possible to replace VOLUME from blood loss by starting an IV, most lay providers are not trained or equipped for this technique. Furthermore, simply replacing blood with IV fluids doesn’t replicate the oxygen carrying benefits of red blood cells. It simply increases the volume and blood pressure of the patient. TCCC (you remember what that stands for, right?) based studies have determined that only replacing volume can be HARMFUL for the trauma patient because increased pressure can cause the bleeding you just got under control to start again. So we can’t just slap on a tourniquet, pump the patient full of IV fluids and send them back out to play.

A trauma exposure patient from a mountain rescue with blanket in the cold

A trauma / exposure patient from a mountain rescue

HEY! What does all this have to do with blankets and getting cold? Well, let’s see.

A military study in Iraq determined that greater than 50% of trauma patients brought into the hospital were hypothermic. “But it’s hot as hell in the desert. How did that happen?”

Following blood loss, a number of things happen to the body (I already said that above) and one of those is that our body’s temperature regulation system can stop functioning. Then physical factors come into play, things like us cutting their clothes away to treat their wounds AKA “exposing the patient”, the patient laying on the cool or wet ground, the patient becoming wet with blood or water, the wet and exposed patient being placed in an air conditioned ambulance or flying around in a cool breezy helicopter and any number of other factors.

So they are chilly, so what? Well the really scary stuff is the other half of that military study. The study found that patients who were SLIGHTLY hypothermic, classified as less than 96.8* degrees, had a 25% chance of death versus 2% for patients with normal temperatures. The chances of survival continue to fall as patient temperature drops until the surprising statistic that 100% of patients with a core temperature below 90* died. That is what is known as 100% mortality and that’s not good.

As if this wasn’t bad enough, it was also discovered that hypothermia is part of something called the “LETHAL TRIAD”. It’s not a Japanese gang and with a name like that I probably don’t need to tell you that it isn’t something you want to be part of. The Lethal Triad is a condition that comes from trauma and goes like this. You lose blood, you become cold, your blood becomes acidotic (acid buildup in the blood) and this leads to coagulopathy (fancy doctor word for your blood stops clotting). This is usually followed by a visit from the man in black and we aren’t talking Johnny Cash here.

Earlier we accepted that “Bleeding is Bad” and now we know that bleeding leads to cold which leads to more bleeding. So it is key to keep the patient warm and to cut off the Lethal Triad before it gets rolling. This is where the blankets come in.

We now include mylar blankets with our BFG medical kits. These are often called “space blankets” and the name comes from the fact that mylar (a heat reflective plastic material) was developed by NASA in 1964 to insulate space capsules. It was soon determined that a mylar blanket can reflect up to 97% of heat and the idea to use it as a blanket was born. Mylar blankets are relatively inexpensive, lightweight, low bulk and useful for keeping patients warm.

An important point to remember – Don’t just throw the blanket over the patient! You need to insulate them from the ground or any other cold/wet surface under them. I like to tell my students to “burrito” the patient by rolling them up on one side (a great time to double check for any injuries to their back side) and then place the blanket under them before rolling them back onto it. Then you wrap the sides up around the patient and gather it at their front. This also allows you to open only a section of the blanket to double check your tourniquet placement or other wound care measures without fully exposing the patient again.

Let’s sum all this information up into a simple Action Plan:

  1. Recognize and stop all bleeding.
  2. Immediately assume the patient is cold. Even when they tell you they aren’t.
  3. Using a mylar blanket (or any other available insulating material) wrap the patient to maintain heat. Being sure to get the material UNDER and around the patient.

About the Author

John “Brad” Gilpin

John “Brad” Gilpin is a prior law enforcement professional who served at the state and federal levels. He was a founding member of the USBP BORSTAR unit serving as Assistant Team Leader / Team Medic and has been involved in advocating tactical medicine skills for LEO’s since long before it was cool to do so.

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