X-Message-Number: 10902
Date: Thu, 10 Dec 1998 18:19:21 -0500
From: Jan Coetzee <>
Subject: hypothermia

Device speeds hypothermia recovery

NEW YORK, Dec 09 (Reuters Health) -- A new armcuff device speeds the
delivery of heat to
the heart and internal organs of patients who develop hypothermia -- a
sudden drop in core body
temperature -- during surgery.

``This gives us the equivalent of an open heat-pipe that leads directly
to the body's interior,''
explained device inventor Dr. Dennis Grahn, a biological researcher at
Stanford University in
Stanford, California. A study testing the efficacy of the apparatus,
called the ``Thermo-STAT,''
was published in a recent issue of the Journal of Applied Physiology.

When body temperature drops, one of the ways the body reacts is by
restricting blood flow to
surface areas especially prone to heat loss. However, this response can
also hinder the
conduction of externally applied heat (from blankets, for example) back
towards the body's
inner core.

Most patients undergoing surgery experience temporary procedure-related
declines in core body
temperature. And studies have linked even mild hypothermia to an
increased risk of infection
and heart problems in surgical patients.

But the Stanford team knew that declines in atmospheric pressure can
hypothermia-restricted blood vessels. Their Thermo-STAT armcuff creates
a tight seal around
the lower arm, while an external vacuum pump triggers a drop in air
pressure inside the cuff. At
the same time, warm water is pumped into the device to deliver heat to
the dilated blood vessels
of the arm. The re-warmed blood then returns to the heart and other

The investigators tested their device on 16 patients undergoing
surgeries, and found that ``the
combined application of heat and subatmospheric pressure to a single
forearm, hand and fingers
accelerated recovery from hypothermia.''

In fact, patients using the Thermo-STAT reached a stable core body
temperature 10 times faster
than patients warmed with traditional techniques. ``When we started
these tests, we expected to
get maybe double the rate of rewarming,'' said study co-author Dr.
Donald Watenpaugh of the
University of North Texas Health Science Center in Fort Worth. ``A
10-fold increase is really

The researchers believe the device could have numerous applications --
from routine use in
operating rooms to the treatment of victims of severe environmental
hypothermia. Since the
device weighs just 3 to 4 pounds, it might easily be carried by
search-and-rescue and paramedic
teams, they suggest.

Thermo-STAT has been patented by Stanford University, and is licensed
for manufacture by the
Aquarius Medical Corp., of Scottsdale, Arizona.

SOURCE: Journal of Applied Physiology 1998;85:1643-1648.

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