8 | New Scientist | 30 November 2019
AT LEAST one patient has been
treated using an experimental
technique called emergency
preservation and resuscitation
(EPR), which cools down the
body and gives doctors longer to
operate, New Scientist exclusively
revealed on 20 November. The
technique is being trialled for
people whose traumatic injuries
are so severe that they would
otherwise die.
It was “a little surreal” when
the technique was first used,
says Samuel Tisherman at the
University of Maryland School
of Medicine. He told New Scientist
that his team of medics had placed
at least one patient in suspended
animation so far, but wouldn’t
reveal how many people had
survived as a result.
EPR is being carried out
on people who arrive at the
University of Maryland Medical
Centre in Baltimore with an acute
trauma – such as a gunshot or stab
wound – and have had a cardiac
arrest. Their heart will have
stopped beating and they will
have lost more than half their
blood. In cases like these, there
are only minutes to operate, with a
less than 5 per cent chance that the
patient would normally survive.
EPR involves rapidly cooling
a person to around 10 to 15°C by
replacing all of their blood with
ice-cold saline. The patient’s brain
activity almost completely stops.
They are then disconnected from
the cooling system and their
body – which would otherwise be
classified as dead – is moved to the
operating theatre. A surgical team
then has 2 hours to fix the person’s
injuries before they are warmed
up and their heart restarted.
At normal body temperature,
about 37°C, our cells need a
constant supply of oxygen to
produce energy. When our heart
stops beating, blood no longercarries oxygen to cells. Without
oxygen, our brain can only survive
for about 5 minutes before
irreversible damage occurs.
However, lowering the
temperature of the body and brain
can slow or stop all the chemical
reactions in our cells, which need
less oxygen as a consequence.
Tisherman’s plan for the trial
was that 10 people who receiveEPR will be compared with
10 people who would have been
eligible for the treatment but
for the fact that the correct team
wasn’t in the hospital at the time
of admittance.
The trial was given the go-
ahead by the US Food and Drug
Administration. The FDA made
it exempt from needing patient
consent as the participants’
injuries are likely to be fatal and
there is no alternative treatment.
The team had discussions with the
local community and placed ads
in newspapers describing the trial,
pointing people to a website where
they can opt out.
Tisherman’s interest in trauma
research was ignited by an early
incident in his career in which a
young man was stabbed in the
heart after an altercation over
bowling shoes. “He was a healthy
young man just minutes before,
then suddenly he was dead. Wecould have saved him if we’d had
enough time,” he says. This led him
to start investigating ways in which
cooling might allow surgeons
more time to do their job.
Animal studies showed that
pigs with acute trauma could be
cooled for 3 hours, stitched up and
resuscitated. “We felt it was time
to take it to our patients,” says
Tisherman. “Now we are doing
it and we are learning a lot as
we move forward with the trial.
Once we can prove it works here,
we can expand the utility of this
technique to help patients survive
that otherwise would not.”
The experimental technique
is only intended for use in
emergency medicine. “I want to
make clear that we’re not trying
to send people off to Saturn,” saysSHAP
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ESNews Special report
Cooling the body to slow
metabolism could give
extra hours to operate10 people
will be put into suspended
animation as part of a trial10°C
The minimum temperature to
which their body will be lowered2 hours
The amount of time patients will
be cooled to slow their metabolismEmergency medicineSuspended animation
Humans have been put into suspended animation for the first time to
give doctors more time to treat severe injuries, reports Helen Thomson