Monday, April 8, 2013

Frostbite and the Frozen Character

In honor of April blizzards, here's a bit about what would happen if your character got stranded and had to walk a distance through snow.
Mechanism of Frostbite

A normal body temperature is 98.6 F or 37 C. Frostbite occurs when body tissue is exposed to temperatures below the freezing point of water (32 F or 0 C).

The majority of cases of hypothermia occur due to exposure outdoors. Alcohol worsens the problem, as does malnutrition, dehydration, and physical exhaustion.

The areas farthest from the heart are most susceptible: fingers, toes, nose, ears, and the face in general.  

With cold exposure, blood vessels constrict in the extremities (arms and legs) to centralize blood flow to the vital organs and maintain core temperature. These remote areas get progressively colder. Brief dilatation of extremity vessels alternates with constriction. As the body temperature begins to drop, the vessels remain constricted. This is the point at which frostbite begins.

The damage from cold is of two types: ice crystals form between cells, leading to cellular dehydration, and blood vessel damage leading to lack of oxygen to cells.

Degrees of frostbite

First degree: Freezing of the top layer of the skin, but still gives to pressure. Numbness, itching, and some pain. No permanent damage.

Second degree: The skin hardens as it freezes. Blisters form. Usually heals, but may have some insensitivity to temperature long term.

Third degree: Freezing into the deeper layers—the skin, muscles, nerves and vessels are affected. Blisters form, which are blood-filled. Permanent damage leading to the need for amputation can occur. The situation is a complicated mix of clotting in small blood vessels, inflammation, and tissue damage.

Fourth degree: Irreversible cell death. The tissue is dead, and must be removed.

It’s common for the complete extent of the damage to take several months to become clear, and therefore the need for medical treatment extends beyond the initial care.


The first assessment involves evaluation for hypothermia—pulse, respiratory rate, and blood pressure. Level of consciousness is next, and then the initial evaluation of the frostbitten areas, based on the degree of frostbite.

Treatment of hypothermia always takes priority. Save the person first, the extremities next.

Next is rewarming of the frostbitten areas, which can be quite uncomfortable (read: painful!) and require pain meds. IV fluids are commonly given as part of this process. Several methods can be used:

Warm water bath—most suitable for first and second degree frostbite. Remove clear blisters. In third degree frostbite, blood blisters are left undisturbed. Pink skin, return of feeling and motion are good signs. Observe for evidence of infection. Some practitioners give a tetanus booster.

External warming with heated blankets—suitable for any degree of frostbite.
Internal warming with warm fluids infused into the abdominal cavity—may be utilized in cases where hypothermia complicates the situation.
In critical cases where hypothermia is life-threatening, the most aggressive rewarming is done with a heart-lung bypass machine.
As with most injuries of this type, prevention is key.
Questions? Comments?


Kelly has worked in the medical field for over twenty years, mainly at large medical centers. With experience in a variety of settings, chances are Kelly may have seen it.

Sometimes truth seems stranger than fiction in medicine, but accurate medicine in fiction is fabulous.
Find Kelly’s fiction at




  1. Wow, that's a lot of useful information.

    And Max says to tell you not to give me any ideas lol He hates being cold, and he's pretty sure he wouldn't care to be a frozen dainty lol

    1. Thanks, Julie.
      And to Max--stay warm, baby!
      Cheers, Kelly

  2. Excellent timing, Kelly. I'm working on a novel set during winter in Minnesota and at least two characters will be affected by frostbite. Thanks for the info.


    1. Here's a question: How about doing a companion post on hypothermia? Thanks if you can.

    2. Hello, Chris.
      I've started a piece on Hypothermia, to be posted later this week! Look for it by the weekend.
      Glad you find the information useful.
      Cheers, Kelly

  3. I had a character get frostbite when the heater in his moonsuit went out. His companion got him to an abandoned shelter and used warm blankets, there was no option for medical treatment. Must have been just first degree since he got better, although he did get put in the hospital when he finally got back to Moonbase.

    1. Hello, Jim.
      Field treatment of frostbite is difficult--most of the time you end up relying on reflected body heat until you can get to medical care--just as your characters did. No doubt the Moonbase had state-of-the-art facilities!
      Cheers, Kelly

  4. You are a walking, typing compendium of ways to die--in detail. :-) I always learn something from your posts. This one is a great one. The chances I get caught in a blizzard are better than someone wanting to murder me, at least I think so... MM

  5. Thanks for reading, MM.
    As we're in the middle of a blizzard here today, I'm staying inside, where it's safe.
    I don't think grammar has led to homicide, although I could be wrong...
    Cheers, Kelly

  6. Fascinating info, Kelly. Saving for sure.

    1. Glad you find it useful!
      Thanks for reading.
      Cheers, Kelly