Indeed, the differences wouldn’t generally be clinically significant (e.g. classifying “severe” hypothermia at 82 vs. 80°F — either way, your patient is still probably comatose or just about, and you still have to gentle). I’m not sure that “stupor” is the word you mean for the beginning of “moderate,” and “inability to move voluntarily” didn’t quite convey “appears dead” to me (as one of my instructors put it) or “coma” (as the AAFP labeled that temperature range) for severe. Also, a mention of bradycardia (and/or initial/unpredictable tachy) might be helpful? But probably most readers have already been taught that. But anyway, the specific breakdown to temperatures and the 1-2 degree comment led me to start looking for sources and otherwise splitting hairs. And perhaps the most incredible thing about having found another two “coldest” resusses is that apparently at least a few people have been revived from “about 60.”

I might still argue that it’s useful to recognize that the hands of you-the-caregiver are possibly >10 degrees cooler than core temp, but could vary wildly, and thus may not be particularly reliable indicators. Anyone colder than my hands (which ordinarily are sufficient to *induce* hypothermia) is in deep trouble. But if I find a (hypothetical) patient who is warmer than my hands, (s)he could still be hypothermic (but will probably be warm enough to mumble to you, unless there was another reason for diminished consciousness). Or if for some reason a patient is trapped and unconscious somewhere and it’s only possible to access the arm, which comes in at, say, 85 or lower, the patient may still be not bad core-temp-wise. Common sense will probably still prevail to tell you that someone found under various conditions may need warming up or at least a few blankets, anyway, even if the patient is not shivering but warmer than the hand (which most people should still recognize as much colder than normal).

Ouch, I hadn’t heard about the connection to the Nazi experiments. That would make sense.

And thanks for including source links on Part 2 (as you often have in the past, but I appreciate it in particular this time ).

Yes, we can estimate core temp with assessment findings. At Wilderness Medical Associates (I am a lead instructor) we teach students that the key assessment findings in determining hypothermia severity are 1) presence or absence of shivering and 2) mental status changes for an awake patient or level of consciousness for a patient that is not awake. With those two assessments you can determine mild or severe.

Dr. Gordon Giesbrecht aka Dr. Ice Cube has done extensive hypothermia research including human subject cooling in controlled laboratory conditions. http://www.umanitoba.ca/faculties/kinrec/about/giesbrecht_faqs.html

Finally, the hand to the abdomen assessment assumes that you, the rescuer, are normothermic and have not been exposed to the same relative cold environment as the patient. Stepping out of the ambulance and touching the patient’s belly is much different than riding a rescue snowmobile for 45 minutes to reach an injured patient in the back country.

The key here was recognizing that the temperature of the caregivers hand should be colder than the core of the patient and if the patients core feels cold to the touch, they are most likely significantly hypothermic.

Regarding the AAFP article, I don’t see anything that contradicts the information provided by the text I cited. Your article lumps symptoms into a more broad range of temperatures. But I don’t see any symptoms on my list that fall into different temperature ranges in your article. In fact. I’m surprised at how well the two pieces match up.

What symptoms do you feel aren’t “matching-up?”

Also keep in mind that moderate and severe hypothermia research is limited because you can’t really freeze people and record their symptoms. So we’re all going off of very little real research. The most comprehensive research numbers come from the Nazi experiments on prisoners pre-Nuremberg and there’s some debate over whether those figures should be used at all because the research itself was unspeakably cruel. Differences from one source to another may be explained by whether or not the chose to include WWII era research. Some do, some don’t.

The figures for lowest successful resuscitation come from a power point that was about six years old. I think your numbers are better and I’ll change the article to reflect that data.

Thanks again for your contribution.

I don’t know that I agree with your introductory characterization of hypothermia as something that happens “secondary to exposure to cold.” I mean, of course for a patient to become cold, their environment has to be colder than normal body temperature, but as you later indicate, anything that causes someone to have diminished heat-generation capacity can cause it. Patients can become hypothermic laying directly on the ground (conductive) when it’s eighty degrees out.

Julio.

Also, I’m not sure what you meant that limbs tend to be 1-2 degrees cooler than core — did you mean blood temperature deep in the thigh, or did you mean somewhere more peripheral? This totally unrelated study ( http://www.springerlink.com/content/bh54458q70244616/ ) mentioned average hand temperature being about 87°F. This other article ( http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1752199/ ) lists differences between core and peripheral more conservatively at 3-8°F in “moderate” environments.

I’m seeing the coldest resuscitations-to-survival as 57.6°F (rectal) for a toddler and 56.7°F for an adult, according to sources cited by the AAFP article above.