Hypothermia Prevention - Post Ice Water Fall

Hypothermia is likely the least of your problems after an involuntary dip into icy water. Drowning and cardiac arrest are the killers here.

Read these, and maybe watch the videos. It's all good stuff, and difficult to summarise.

http://beyondcoldwaterbootcamp.com/4-phases-of-cold-water-immersion

http://beyondcoldwaterbootcamp.com/en/rescue-a-treatment

Basically, adults need over 30 mins in icy water before you get even mildly hypothermic. From beyondcoldwaterbootcamp:

While it varies with water temperature and body mass, it can take 30 minutes or more for most adults to become even mildly hypothermic in ice water.

http://sportsscientists.com/2008/01/exercise-in-the-cold-part-ii/

Perhaps the first, and maybe the most surprising fact about cold water physiology, is that your body has too much heat to become hypothermic within about 30 minutes, no matter how cold the water is!

... and from @imsodin's link:

Even in ice water hypothermia does not set in until after 20 to 30 minutes, depending on the amount and type of clothing.

If you're out of the water and wet, you will lose heat by evaporation (as well conduction and convection), so dry clothing and dry body are important.

posted over 8 years ago

CC BY-SA 3.0

Roddy‭

126 reputation 1 38 13 0

I try to address the situation you are asking about, even though I think you already did a good job so this may not be overly helpful/new. Additionally in one of your referenced answers that is actually about rescuing someone out of the water, there is already a great answer by D.Lambert on what to do after rescuing, so my answer will overlap greatly (I still do not think the question is a duplicate, more like this answers belonged here). As you are asking for references, I take this information from my favorite outdoor medical guide by the Swiss association for mountain medicine and the Swiss Alpine Club. So the situation as I understand it is, that we have a wet patient which was immersed shortly in icy water. I assume we now are out of danger of falling into water again.

This person will most likely not yet suffering from hypothermia or if so from first stage hypothermia, meaning he will shiver and be apart from psychological shock be of clear consciousness.
If you are very exposed to wind/rain/snow and have the possibility of getting to a somewhat shelter spot in the immediate vicinity - get there immediately. Is such a place further away try to provide some protection by other people, backpacks, ... while stripping the patient and getting him into dry clothes. Ideally these are spare clothes (in cold weather you should have at least some anyway) and what other can spare.

No there are two scenarios: The patient might feel up to moving by himself. In this stage this is optimal, as a lot of heat can be produced by activity. Just start easy and immediately abort if the patient feels dizzy. Otherwise you try to isolate the patient as good as possible. If you have some kind of heating device (like those little chemical bags) put them onto the first layer on the torso, never directly onto the skin. If you have a sleeping bag, get the person in it, then use rescue blankets, bivy bags, etc. as an outer protection. Of course if two people fit into the sleeping bag, all the better, that's just another heating device inside. However as mentioned in the comments, this may be of limited help. It is likely the person can do more good on the outside (transport, shelter, fire, ...) than he helps inside the bag (thanks Roddy). Unless psychological issues are included, then the cuddling can be highly effective :)

A person in this stage should be given hot liquids to drink, preferably sugary, and motivated to move, even in the sleeping bag. After these initial steps you want to get to a sheltered area. Without such a place you need to improvise: Create some shelter against wind (e.g. snow cave, beside a rock, under tree using branches) and start a fire. This is a whole topic on its own. Thus further cooling should be preventable and if there are not further injuries the patient should recover and immediate evacuation to a hospital is not necessary.

However if you cannot accurately protect the patient it can get life threatening fast. Its out of scope, but just as a warning: When the patient consciousness gets clouded and/or stops shivering this may already be stage two hypothermia. You cannot do much more than prevent further heat loss, but now the patient should not be actively moved and not given anything to drink, unless he is on clear conscious (danger of aspiration). In this case organize evacuation asap and be on alert to perform CPR and remember: A patient with hypothermia is never dead unless he is warm and dead.

Addressing your specific questions:

• Useful gear:

Sleeping bag, bivy bag, chemical heating thingy, rescue blanket and thermos flask (with hot liquid) (I know, kinda obvious and not very light-weight).

• Correctness of stated example:

Well as far as it was described, sounds good to me.

• Most immediate/primary concern:

Prevent further heat loss (again, obvious) - the rest follows.

• Day hike with limited gear:

Improvise the heck out of the situation. In this situation the chance is big, that you cannot provide ample protection from the cold, but on a day hike external help should be fairly quickly available - do not lose time, organize help immediately if in doubt about whether you can handle it on your own.

Reference: A.G. Brunello, M. Walliser, U. Hefti, Gebirgs- und Outdoormedizin (SAC Verlag, Bern, 2011), p.232.

posted over 8 years ago

CC BY-SA 3.0

imsodin‭

41 reputation 26 171 6 0

My copy of Buck Tilton's Wilderness First Responder notes that for cold water immersion, aside from providing standard treatment for hypothermia, the patient should be "handled gently, lifted from the water, and kept in a horizontal position". Dry them off, and insulate them from further cold before you think about building a fire. (The reason behind keeping the patient flat is to avoid stressing their heart.)

If you fall in yourself, use the first minute to get control of your breathing, then assume you only have about 10 minutes of useful muscle activity. Use that time to pull yourself out or swim to safety.

In terms of re-warming, the vast majority of the work will be done by the patient's own body: your role is to support that by minimizing their external heat loss and topping up their fuel supply (calories) if they are conscious. Adding external heat sources may help a small amount.

Now, there is some contradiction between the need to get someone into dry clothes and the need to keep them insulated from the environment; obviously if they are in the open with howling winds and rain it's probably a bad idea to pull off their clothes. So, let's look at some other protocols that may be better suited for the solo traveler or those who were only briefly immersed (e.g. fell in and climbed straight out).

For this I'll reference a "re-warming drill", which you can read an example of at https://www.sitkagear.com/insight/a-navy-seal-rewarming-drill. This method relies on both body heat (as previously mentioned) and also proper gear selection: wicking fabrics and synthetic insulation. If you don't have the proper clothing, it's not likely to work very well. The type of clothing system mentioned in this article may be referred to by many different acronyms; searching for ECWCS or PCU should give good results.

In the first form of the drill, the troops pair off and immediately add synthetic insulation layers. One person sets up the tent, the other sets up a stove and gets snow melting or water heating. With that done, both burrow into their (synthetic) sleeping bags. As soon as they can, they then get some hot drinks and calories into them and lie back down.

The second form of the drill addresses the case of what to do without tent, sleeping bag, or stove. In that case, the troops simply put on their synthetic insulation layers and their packs, and then marched for a few hours at a slow, easy pace (enough to generate heat, but not to sweat).

Having described a pair of options, you can also look at the Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia section on field re-warming. It suggests that patients not be immediately allowed to stand or walk, and that delaying exercise for about 30 minutes will help reduce the risk of afterdrop.

On a personal note, I haven't yet decided to jump in an icy lake, but I can attest to the drying abilities of modern synthetics. This past summer, after getting my hiking pants largely soaked in a thunderstorm, I added GoreTex pants over them and after a moderate amount of walking had completely dried them out.

posted over 8 years ago

CC BY-SA 3.0

requiem‭

261 reputation 0 69 26 0