- Most important:
- Remove clothes
- Cover with dry warm blankets and bedsheets
- Bair hugger and/or Arctic sun (no real difference between the two. Bair hugger easier to initiate in ED. Cover up everything, including face too)
- Warm room / heat lamps
- Second most important:
- Warmed humidified O2
- Warmed IVF (but each 1L at 42 degrees will only raise body temp ~0.3 degrees C)
- Generally initiate these measures above for anyone less than 34 degrees (moderate hypothermia)
- Other considerations: NG lavage, bladder irrigation, thoracic lavage, peritoneal lavage are all invasive and time consuming with only at best being moderately effective. The easiest to perform - NG lavage and bladder irrigation are really minimally effective.
How do I get warmed IVF?
How do I get warmed humidified O2?
- Patient breathing on own?
- Ask for a "blender". RTs can get this from upstairs. You can attach it to a facemask and provide high flow O2. This is the same device that we use to initiate high flow NC for our peds patients.
- Many BiPAP machines have a warmer/humidifier attached in line. Check with your own department before to find out if this is the case.
- Patient intubated?
- Modern ventilators can provide warmed/humidified air. However, many EDs only have access to older ventilators so again, know what's in your own department.
Rewarming in critically ill/hemodynamically unstable/peri-code/code
- ECMO (best option when able, but not available most places)
- CVVH (way easier than dialysis to initiate. You need to be able to place a Meherker and a nephrology nurse able to bring and operate the machine. That's basically it.
- Hemodialysis (hard to initiate - unlikely to be a feasible option)
- Cardiac bypass (hard to intitiate - unlikely to be a feasible option)
- All these methods can raise body temp at least 2-4 degrees C per hour.
Patient is bradycardic? Should I pace them?
- In general, pacing is not indicated in the hypothermic patient. If they have a pulse, continue to rewarm and the bradycardia should resolve.
- Atrial fibrillation is the most common arythmia of hypothermia. Will convert to sinus with rewarming.
- Classic board exam question is bradycardia with osborn waves but only see this in ~30% if severe hypothermic patients.
- Somewhat controverial. Some say no CPR for PEA as you could induce a dysrhythmia. Some say shock only once and if it doesn't work, don't shock again until at least 2 degrees warmer.
- Most would say if there is no pulse, you should be doing CPR.
- Every 2 minutes, if there's a shockable rhythm... shock! If it's still a shockable rhythm 2 minutes later on rhythm check, shock again! It doesn't take that long to do. Just make sure you continue to re-warm them during the code.
- Be careful with meds. Consider only giving 1mg epi ONCE rather than repeat dosing over the course of the code. As they re-warm, they will vasodilate. If they have a bunch of epi from multiple rounds sitting in their vasoconstricted extremity, they could get a huge surge of epi all at once.
When should I call the code? When is the patient truly warm and dead?
- Most textbooks would say 32 degrees - if there is still no pulse, resuscitation efforts should be terminated.
- Alternatively K > 12 mmol/L warrants termination of resuscitation efforts.
What other interventions/testing should be done?
- Does the patient have frostbite?
- Patient needs aggressive rewarming of areas of frostbite. Consider NSAIDS, calcium channel blockers, and if there are signs of decreased perfusion in the hands or toes, they may be a candidate for tPA/heparin.
- Was there trauma?
- If patient was found down, consider imaging of head/c-spine if altered and obviously, perform a thourough physical exam.
- Was this an intentional self-harm attempt?
- Consider checking acetaminophen, salicylate, ethanol, EKG.
- Incidentally, ethanol causes vasodilation making hypothermia more severe and re-warming techniques potentially less effective.
- How long was the patient down?
- Consider checking a Creatine Kinase - typical symptoms of rhabdomyolysis can be clouded by hypothermia.
- Is this for sure accidental hypothermia? Could the patient have just incidentally been found outside for another reason? Maybe they were confused or just incidentally picked up outside.
- Differential for hypothermic patient:
- Accidental hypothermia (environmental exposure)
- Myxedema coma
- Adrenal insufficiency
- For these secondary causes, your goal is not active re-warming, but to treat the underlying cause. For example, treating myxedema coma primarily by active rewarming will result in vasodilation and secondary cardiovascular collapse. Focussed treatment would be removing cold clothes + warm blankets but not other active rewarming techniques + medical treatments (T3/T4, steroids, fluids, etc)