*** Hypothermia Inhaler Treatment ***

From: ftim@mail.voicenet.com
Newsgroups: misc.emerg-services
Subject: Re: treating hypothermia in the field
Date: Wed, 20 Dec 1995 14:27:40 GMT
Mike Doyle <mdoyle@SARBC.ORG wrote:

Western EMS units have had "back-packable" units to warm air for
hypothermia treatment for some time.  I believe it uses a chemical
reaction to generate the heat.

Tyler Groo writes:
I've never seen warm O2 in an ambulance (except in an isolette).

Anybody have thoughts about the ability of a humidifier to
significantly warm O2 during its short path through the water?
I know experimentally that it's practical to warm the water 10-20F
by wrapping the humidifier in chemical hot packs, but I can't
think of a simple way to evaluate changes in the gas temp.

Maybe some physics pro knows enough heat transfer mechanics to
state with confidence that the contact duration is way too short?
Or not?  If somebody has means that I don't to measure or calulate
this approach, let us all know what you find out...
--

Tyler Groo, EMT-B    |  Rager Emergency Services (RES)
"Don't blame them    |  171500 Beaver Creek Rd., Paulina, OR 97751
 for what I think."  |  (541) 477-3162/477-3713
BLS ambulance serving parts of Crook/Grant/Wheeler/Harney Counties


Oxygen doesn't have much mass. Mass is helpful to conduct heat. Perhaps you
could mix the O2 with the water, with the water providing the mass directly.

One way to do it is create water vapor (steam), perhaps by using some kind
of kettle, add ambient air to cool the steam down, add a water trap for the
condensate, and add O2. This could be delivered to a mask at approx 42-43
deg C (110 deg F). The saturated air provides the mass. Result: warm
humidified air (with O2) delivered to the patient by mask.

Benefits to the Patient:
Three things happen now: One, the 100% humidified air reduces or stops
dehydration. Two, heat is donated thru the lungs to the thoracic core,
thereby stopping further cooling of the core. A decision can be made to
rewarm or just stabilize. Three, respiratory heat loss is stopped - it is
usually the hardest one to deal with. (The patient would already have been
insulated maximally.)

All of this happens without introducing any external stimuli, which could
hamper the recovery of the patient.

There is little or no chance of premature vaso-dialation, muscle-pumping etc
BTW, a unit called RES-Q-AIR was invented for just this purpose.

Hope this helps.
Cheers,

Mike

Mike Doyle <mdoyle@sarbc.org
Search and Rescue

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