Severe Accidental Hypothermia
It is winter and that means cardiac arrests coming in with extremely low body temperatures after environmental exposure. How do you treat these patients? How do you rewarm if you don't have bypass?
Predisposing factors
hypoglycemia, malnutrition, ETOH, Addison’s, infection, and Myxedema (especially if failure to rewarm)
In urban environments, in patients > 32° C, failure to passively rewarm at least 1 C per hour should make you suspect one of the above factors. (Acad Emerg Med 2006;13(9):913)
Do not need to worry much until temp hits ~32° C
Bradycardia (refractory to atropine), but should not be treated anyway as it is appropriate to body temperature as long as it is sinus brady; but if you needed to, you can pace hypothermia internally (Ann Emerg Med 2007;49(5):)
Labs
FS, CBC, Lytes, TFTs, Cortisol, and blood cultures if you can't figure out why a patient got hypothermic or is not warming appropriately
Get Temperature Probe in early for sick patients
Place rectal probe in 15 cm or much better IMNHO is an esophageal probe
See this post for how to place the esophageal temperature probe
Active Rewarming
Active rewarming if pt temp <32° C, CNS sx, or age extremes
Rewarming Methods
Shivering 1.5° C/hr
Warming Blanket 2° C/hr
Warm O2 1 C/hr with mask; 1.5° C/hr ET tube
IV Fluids do not add, but do not take away either
Peritoneal Lavage 3° C/hr
Thoracic Lavage with Chest Tubes 3-6° C/hr
Cardiac Bypass 9-18° C/hr
When to Stop Rewarming
If K>10, pt is not coming back, even if cold and dead
Must be greater than 30-32° C degrees to be considered dead
Rewarming with Chest Tubes
32-36 F Chest tubes one anterior and one posterior lateral
Use Level 1 Device or similar to pump warm fluids into the anterior chest tube
attach auto-transfuser or pleur-evac to posterior-lat chest tube to allow cont. emptying
Review article with two case reports (Resuscitation 2005;66:99-104)
Update:
Instead of salem-sump adaptors, use the luer to XMAS tree adapters made for this purpose. See the Blakemore Post for more on this item.
Extra-corporeal rewarming
Easiest method is to place an HD catheter and then get a dialysis machine to do CVVH or standard HD
CAVR Level I Rewarming
Here is an actual protocol from a Trauma Nursing Journal
J Trauma 1991;31:1151 and 1992;32:316 both by Gentilello
Bypass Rewarming
Crit Care Med 2011;39:1064
Update
Best Review Article (NEJM 2012 367(20):1930)
Give a bunch of fluids
Afterdrop is a myth
30-32 is cutoff
ICAR MEDCOM Guidelines (Scand J Trauma, Resus, & Emerg Med 2016;24:111)
Additional New Information
More on EMCrit
IBCC chapter & cast: Hypothermia(Opens in a new browser tab)
Bonus – Passing the Esophageal Temperature Probe(Opens in a new browser tab)
Additional Resources
Professor
Nassau University Medical Center
No conflicts of interest (coi).
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Scott, You advocate using iced saline IV to induce hypothermia. Why do you say warmed saline is ineffective to rewarm patients? Seems that if one is effective the other should be too. Having just attempted–ultimately unsuccessfully–to resuscitate a hypothermic immersion victim for nearly five hours, I appreciate you covering this topic, although I wish you had done it just a couple of weeks sooner. We used a poor man’s version of two chest tubes. I infused saline warmed in a microwave using a 60 cc syringe about 300 cc at a time through the anterior tube while the posterior tube… Read more »
Chris, All I can tell you is that iced saline has been proven to cool patients. I have seen no such data on warming accidental hypothermia with warmed fluids. In beagles, fluid heated to 140 F given centrally will rewarm dogs, but good luck on giving that temp fluid to humans without a study. I have seen little effect on my patients and even in lethal triad hypothermia, warmed fluids don’t seem to warm patients. I am sure some of the physics geeks who read the blog might give an explanation. Best way to fix the coagulopathy is to get… Read more »
Ok – here is a “geeky” explanation: – In order to understander why the rewarming effect of fluids are minimal it is helpful to review the concept of specific heat. Specific heat is defined as the number of kilocalories (kcal) required to warm 1 kg of a substance by 1°C. The specific heat of water is 1 kcal/kg/ °C, and thus 10 kcals are required to raise the temperature of 1 kg (1 L) of water by 10°C. The specific heat of the human body is 0.83 kcal/kg/°C. One can calculate the heat needed to raise the temperature of a… Read more »
ahhh, now that you say that it makes complete sense. When we are using iced saline, the patient is 36 C and the fluid is 4 C–big difference. When we want to use warmed fluids, the patient is 28 C and the fluid is 40 C–much smaller transfer of energy. Brilliant. That is why the rat studies with the fluids much hotter, given centrally work. Thanks, Soren.
What do you tell your prehospital providers to do (or not to do) with respect to rewarming the hypothermic patient?
Unless you are in the wilderness, I would not spend time on rewarming. Supportive care and get them to a hospital.
Scott, Excellent review as always! I recently reviewed our protocols for prehospital EMS/SAR treatment of accidental hypothermia and was surprised by the lack of data for anything we do with regard to hypothermia cardiac arrest management. The standard mantra of limiting ACLS drugs and shocks until target temp of 30C is achieved is based on almost nothing, but gets repeated in perpetuity. Similarly, there are significant changes in the 2010 AHA guidelines regarding the management of accidental hypothermia arrest – also based on very little data. AHA now suggests that standard ACLS drugs and electricity protocols may be followed, but… Read more »
Well it’s great to have someone share my frustration at the COMPLETE absence of evidence-backing for any of there recs.
For me, if I can’t feel a pulse, I’m doing compressions–not just for perfusion but b/c my rewarming depends on blood circulation.
I would modify your last paragraph to say, if patient hits 33 C and is not waking up enough to follow commands, then leave them there.
thanks for the comments, Scott
Just FYI…not to belabor the point…the latest version of UpToDate written by well-known expert on the topic Dr. Daniel Danzl (among others) agrees with your decision to start compressions if no pulse appreciated: “We believe that chest compressions should be performed in patients who manifest an organized rhythm on a cardiac monitor but have no pulses and no other signs of life. ” This is probably a best expert guess/consensus, as I have seen recommendations waiver over the years. Others have considered an organized rhythm to be a sign of life and recommended holding chest compressions in the presence of… Read more »
Scott, I didn’t hear you mention bladder or whole bowel irrigation as options. It is my understanding that bladder irrigation won’t get you rapid rewarming rates due to limited surface area, but it still seems to me to be a viable option in the non-crashing severe hypothermic since it is so easy to do. I imagine that electrolyte fluctuations make whole bowel irrigation less appealing and, perhaps, not worth the effort. My go-to for the peri-crash or the coding hypothermic has also been thoracic lavage but the literature describes relatively rapid rates of re-warming (2-4 degrees C/hr) with peritoneal lavage… Read more »
As you mention bladder doesn’t get you much, so not worth it to me. Whole bowel is fraught with all sorts of peril in the best of cases, I’d avoid it in my sick patients. All I care about is heating the heart enough to get a perfusing rhythm, so I go to the chest. Peritoneal is effective, but I don’t want to violate the belly. Way to easy to screw up. You are essentially doing 2 perc. dpls; when you look at the complication rate for that, it becomes not worth it for me. As I mentioned on the… Read more »
Can you find articles citing specific rates of rewarming for bladder irrigation?
Any thoughts to pulmonary edema?
can you be more specific, Sarah
I am a new EMT and just started listening to your pod casts. I have found them to be very informative. I have worked in the colder northern states, Alaska being one of them. I know pulmonary edema can be present when patients are in the colder climates for an extended amount of time. I know when you must take extreme measures to warm a patient your main concern is getting the patient warm and then getting their heart to start if it hasn’t already with the rewarming. So after rewarming, and restarting the heart, will pulmonary edema subside or… Read more »
Sarah, I am only familiar with cold-immersion pulmonary edema, not cold induced probably b/c I live in NYC and am not a wilderness guy. Can any of you other folks help Sarah out with an answer?
I think you are referring to what is know as subacute or chronic accidental hypothermia. The patient suffers prolonged, milder cold exposure and will correct the hyperthermia induced fluid losses by oral intake. Aggressive fluidresuscitation i these patients can precipitate pulmonary edema. Like everything else in the accidental hypothermia business – which is essentially non-evidence based – no specific guidelines exist (to my knowledge). I believe the treatment follows standard treatment for pulmonary edema. At least thats what I would do.
Does pH help to prognosticate (like hyperkalemia >10) and if so at what level.
I was at a talk where, a cardiac surgeon indicated that one should warm up a body titrating pH level. If the pH is low ( I cannot remember the level) one should cool them again. I believe the rationale is that the “frozen” metabolic waste is released upon warming and hence to warm slowly.
Any comments?
haven’t seen any lit on pH. The card surgeon’s approach seems unsupported and is predicated on the patient they would see…the patient already on bypass–good luck having precise control on the non-bypass patient.
Hey Scott Love the podcast as always. Accidental (or at least non-therapeutic) Hypothermia is a subject close to my heart (!), and our shop down in darkest Tasmania has a bit of experience with it. The pleural lavage via ICC’s has been successfully used here. Direct rapid warming of pericardium and subsequent early ROSC with simple equipment (despite lag of core temperature measurement) is the obvious advantage in theory and in practice! I have access to a couple of great images and bits of data from a case managed by a colleague which I will share with you if I… Read more »
would love that!!!
And for what it is worth, 45 litres of normal saline were microwaved to approximately 40 degrees celsius by a chain of orderlies and poured down the ICC’s into the left chest – low tech, but simpler than a level 1 warmer, plus faster!
simpler I’ll buy
faster? Level 1 does 1 liter a minute; can your pour-folks beat that?
They were pretty slick and they did get 45 litres down that tube fairly fast, but I concede probably not any faster than a Level 1! Jo Kippax has a great graph of core temp measured by urethral probe mapped against time and blood pressure with ECG and timing of clinical events superimposed, plus a great CXR and clinical plus logistical images. He will hopefully get in touch with you himself. Well worth a look!
Hi Scott,
We’ve found that the 8.5 F biliary drains we use as pigtail chest tubes have the standard IV connector already built in, which we can then use for warm fluids off the level 1 infuser.
Essentially the set up is one pigtail chest tube hooked to the level 1 and then one standard chest tube to suction per thoracic cavity.
that is a great suggestion!
Are you preferential to the esophageal temp detector for a particular reason, or would you be just as happy with a temp-sensing foley? Seems like that might kill two birds with one stone.
foley doesn’t track rapid temp changes
Scott, I did a pretty extensive search on what constitutes a temperature sufficient to terminate resuscitation efforts in the severely hypothermic patient. There is “insufficient evidence” to dictate what is “warm and dead.” I went back to the Bible of ACLS, the Textbook of ACLS, 2nd edition (when they published all of the science in the manual along with recs – what an intimidating textbook) and from that point forward, the recs have been “the clinical maxim that patients who appear dead after prolonged exposure to cold temperature should not be considered dead until they they have restored to near-normal… Read more »
thanks for trying buddy!
Are there any general guidelines in hospital for what is too cold to resuscitate?
I work prehospital in a very cold place, and we are allowed to terminate resuscitation if certain criteria are met, such as ice crystals in the airway, body too frozen for chest compressions or a rectal temp below 60 degrees F after 5 minutes of assessing the temp. Is that 60 degree number also accepted in hospitals or is a person that cold so rare there aren’t any specific guidelines?
yep, the latter. Most prehospital hypothermia termination protocols are predicated on a balance between chance of recovery vs. difficulty of transport. In NYC transport doesn’t present too much trouble, so they all come in and then we decide.
Might be rare, but the record-low (13.7 °C [56.7 °F]) fascinating case of Dr. Anna Bågenholm who not only survived but recovered sufficiently to finish medical training and return to skiing is a stark reminder that under the right conditions good outcomes are possible despite prolonged cardiac arrest at ridiculously low temperatures.
great addition. i will add that palpating a pulse can be very difficult in these folks. we use a femoral a-line to make the rosc determination.
hi
You seem to have ha a slip of the keyboard. Tha Annals paper is on external not internal pacing.
Thanks fir the good work
Alberto
Oops I forgot to ask:
When would you want to pace a bradycardia ? Presence of shock and less than what ? Rule of thumb ?
Thanks
Alberto
I think only in conduction abnormalities like heart block
Hello,
Drugs supposedly do not work en severe moderate hypothermia:
When you intubate uncouscious hypotherlic patients, do you use RSi drugs ?
I did not find this anywhere so aI suppose people don’t know.
What do you do ?
Thanks
drugs do work, they just take longer. I think you are fine giving sux
Thanks,
I suppose that this is what you do ?
yes, and sedatives if the patient is responsive to stimuli
Thanks for the great education.
One of our mountain rescue gurus used to recommend a K > 9mmol/L as an indication for stopping resuscitation. His thinking was that if the patient died then got cold the K would be high. If the patient was just hypothermic the K would be less than 9. Is there any truth to this?
I too came across this when researching the show. Not great evidence, but it sounds reasonable.
Hi Scott just catching up on my podcasts and heard this one the other day. I just wanted to add an emphasis and a reference. In this paper: Rewarming rates in urban patients with hypothermia: prediction of underlying infection Delaney, Kathleen A; Vassallo, Susi U; Larkin, Gregory L; Goldfrank, Lewis R 2006 Sep;13(9):913-921, Academic emergency medicine They found that the rate of rewarming (or the inability to rewarm) a patient with hypothermia was correlated with underlying infectious etiology of the hypothermia. Although it was not the emphasis of your talk, with milder degrees of hypothermia I would think the safer… Read more »
Two great additions, buddy
Hi Scott, Thanks for all your hard work, I love your podcasts! I am an EM pharmacist in Boston and we encountered this situation a few weeks ago, but actually were unable to rewarm our patient above 72F. Patient was found down outside, intubated, pulseless upon arrival and the entire time he was in our trauma bay (3.5 hours of CPR total). The patients temperature started in the low 60s, we did L sided thoracic lavage, warming blankets/lights, bladder irrigation, warm O2, gastric irrigation with warm fluids, rectal probe in place (changed twice and readjusted to make sure it was… Read more »
Usually means the patient is irrevocably dead. What was the initial potassium level?
Thats the conclusion we drew after 3.5 hours of CPR, but we had multiple discussions of when we should stop, we could really find a definitive conclusion or resource.
Their K was 4.2
Matt Hendrickson, staff physician at St Agnes (Fresno, CA) and California Med Ctr (Los Angeles). Huge fan of yours for many years!! The 2012 NEJM review article by Brown referenced by you and in the 2015 LLSA reading list recommends using thoracic lavage only for patients with no vital signs which conflicts with your recommendation for lavage on patients <32. What are your thoughts?