Responding to Hypothermia

Part 2 of a 2 part series. (Part one is here.)

In our last post we looked at some of the causes of hypothermia, both typical and atypical. Then we talked a bit about the recognition of the hypothermia progression and what patients might look, feel and act like as they progress through their hypothermic condition.

Now let’s look at some of the guidelines for treating our hypothermia victims.

On the surface, treating hypothermia might seem deceptively simple. The treatment of mild hypothermia often is simple. Bring them in, stop the cooling and rewarm them. But as we progress into moderate and severe hypothermia, things get more complicated. Here are 12 guidelines to consider when the patient is more than just a little chilled.

Stay warm.

As much as it pains me to make a statement this obvious, please forgive me. Hypothermia patients are often found in cold, wet environments. You need to be better prepared than they were to work in that environment or you may find yourself in a similar predicament.

Dress warm. Use layers and be prepared to work in the cold for alonger operational period than your best case scenario.

Remove the patient from the environment.

And stop the cooling process. In our rush to initiate more advanced warming techniques, we can sometimes forget about the basics. Remove wet clothing. Water conducts heat 25 times faster than air. That’s why water i so often associated with these events. If the patient is wet, from any source, to any degree, dry them.

If the patient is found in a cold environment, getting them out of the environment is a priority. Find a dry, warm place to initiate rewarming and treatment.

Don’t be fooled by your thermometer.

Most standard thermometers and some tympanic thermometers won’t read below 94 degrees fahrenheit. Do you know the lowest reading your thermometer is capable of producing? If not, you may vastly overestimate the patients temperature.

Assessments findings are a much more reliable indicator of hypothermia severity than an over-the-counter thermometer. Is the patient still shivering or have they stopped? How well is the patient mentating? Pay more attention to your patient than your thermometer.

Check the glucose.

Patients who shiver for long periods of time may be glucose depleted. To help them assist in their own rewarming process, a course of glucose may be indicated. Check the blood sugar and consult with your base doctor on the best course of glucose management.

Avoid rough handling.

Individuals in moderate to severe hypothermia stages become more susceptible to sudden ventricular fibrillation. Bouncing, jarring and rough handling may precipitate a deadly arrhythmia. Once the heart fibrillates, cardiac arrest is difficult to manage.

Also keep in mind that cold and frostbitten skin is very delicate. We should avoid rubbing or scraping the skin. Straps should be padded and hot packs and other active rewarming devices should never be laid directly against the skin.

Support the airway as gently as possible.

Moderate to severe hypothermic patients may breath slow and shallow. We are accustomed to managing the hypovetilating patient aggressively, but aggressive airway interventions may not be warranted due to the patients decreased oxygen demands. And interventions like nasopharangeal airways and nasal intubation may precipitate lethal arrhythmias. Use the least aggressive for of airway management appropriate for the patients condition and respiratory status.

If you don’t think they have a pulse, check again really, really hard.

The American Heart Association is currently recommending that a professional resuer feel for a pulse on a hypothermic patient for 45 seconds. Personally, I’d feel for it for even longer. then I’d auscultate for it and then I’d feel for it again.

Once the patients skin is cold and the peripheral vasculature is constricted it may be phenomenally hard to feel a pulse. If the patient’s heart is still beating there’s a great chance that it’s circulating enough blood to accommodate the patients decreased metabolic demands, and far more effectively than your chest compressions.

Once we begin compressions we can almost guarantee that the beating heart will transition into v-fib and the possibility of a successful resuscitation becomes highly unlikely. Some guidelines even recommend forgoing CPR if you are within 3 hours of definitive care. If you need to do compressions, do them. But make darn sure you need to do them first.

Only defibrilate once.

That goes for AED shocks as well. If the first shock doesn’t work, neither will the second or the seventh. Try defibrillation one time and then put it aside and continue CPR until the patient can be warmed.

Skip the cardiac meds if the temperature is below 86 degrees.

Medication administration through peripheral IV’s is ineffective in significant hypothermia. Worse yet, we stand the risk of loading the patients peripheral vasculature with unmetabolized meds that won’t become available until the patient is warmed enough to begin utilizing their peripheral circulation.

If those vasoconstricted veins are loaded with cardiac medications, we increase the risk of cardiac arrest during rewarming. Some systems my allow for one round of cardiac meds, others may say stick to the basics until adequate rewarming can be achieved.

Use warm IV fluids when possible.

Many newer rigs out there have IV warmers in them. If that includes you, great. Infuse the warm stuff. If your rig doesn’t have a warmer, you may be able to warm a couple of bags by throwing them on the dashboard and cranking up the heater/defroster. be careful. we want warm fluid, not hot fluid. and you may want to warm up a could extra bags to tuck under the blankets with the patient.

Recognize the potential for renal failure and other warming complications.

There are many complications associate with the rewarming of serious hypothermic patients. They are dependent on the degree of hypothermia and the length of time the body remained cold.

Metabolic acids can build up in limbs and cause a generalized metabolic acidosis during rewarming. Muscles may break down in a process called rhabdomyoloysis and the circulating cellular byproducts put the patient at risk for renal complications including kidney failure.

Nobody is authorized to be dead until they are warm and dead.

Patients who attempt to die while hypothermic need to be advised that, in EMS, nobody has permission to be dead until they are adequately warmed. If a stern warning is insufficient, initiate CPR. And don’t stop unless they are warm and still insist on being dead.

As we saw in the last article, a few folks have been resuscitated from remarkably cold temperatures and incredible exposures. The body’s neuroprotective responses to hypothermia allow the body to go for long periods with little oxygen and the signs of severe hypothermia mimic death.

We can’t be certain that resuscitation is impossible until we’ve warmed the patient and allowed them a chance for conversion at normal body temperatures. Bring lots of rescuers; it may be a long drive.

So hopefully this gives you a solid overview of the general principals of hypothermia response. Treatment of hypothermia patients is a rapidly evolving field. Know your protocols and regional preferences for addressing this type of emergency. For more information, you won’t find anything better than the work of research physician Gordon Giesbrecht at The University of Manitoba. (He also happens to be a really nice dude.)

Now it’s your turn: Do my guidelines jive with your regional protocols? What types of things are you doing in your system to treat hypothermia? Leave a message before you go. I’d love to hear from you.

Comments

  1. Hey Steve,

    Awesome post as always. In my system we don’t use thermometers. Would you say this is a detriment in anyway? Or better because then if forces us to focus on the person and not on the thermometer.

    Also, local protocol says we should passively rewarm a patient unless transport to the hospital is greater than 30 minutes. Any ideas on what we could do to best help them other than taking off wet clothing and covering them with a blanket?

  2. Steve, enjoying this series and how you are bringing so many resources together.

    I think a patient can be cold and dead. If there chest is frozen … frozen like a piece of frozen meat in the freezer they are dead. If they have ice in their upper airway they are dead.

    Jeremy the presence or absence of shivering and the patient’s level of consciousness are very useful for determining if the patient is in mild or severe hypothermia. Additionally an oral temp is going to be difficult to obtain in a uncontrollably shivering patient or a patient that is V P or U on the AVPU scale. With the exception of cardiac drug administration all of the treatments Steve has described are independent of knowing the patient’s temp.

  3. One of the best ways of passively rewarming a patient is to jack up the heat.

  4. Greg: if the patient is frozen why not leave them like that until medical technology that could repair frozen tissue can be deployed?

    Raising the temperature would only inflict more damage through re-initiating deleterious biochemical activity (acute ischemia / immune-inflammatory cascade leading to MODS etc) which would indeed be irreversible.

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