CARDIOVASCULAR
Targeted temperature
management for cardiac arrest
This review aims to look at the theory behind targeted temperature
management and how it is applied clinically, with attention to new research
in this field and its impact on patient survival and neurological recovery
Ben Avery
MBBS BSc (Hons) MRCP
Specialist Registrar
Anaesthetics
Melinda Brazier
MBBS FRCA FFICM
Consultant Anaesthesia
and Critical Care
St Peter’s Hospitals
NHS Trust, UK
In England in 2013, there were 28,000 cases
where emergency medical services (EMS) were
called to attempt resuscitation for out of hospital
cardiac arrest (OHCA). 1 Other large studies give an
incidence of OHCA of approximately 80 per
100,000 patient years. 2 Worldwide, this figure is
significantly higher than in Asia but falls slightly
behind the USA and Australia. 2 These numbers
are only the amount of cases where EMS were
called to OHCA, not how many were treated,
or indeed how many had a cardiac cause, or
how many of those with cardiac cause were found
to be in ventricular fibrillation (VF). This is
important as there are positive survival rates
associated with VF cases of OHCA versus any
other. 3
Mild therapeutic hypothermia (MTH),
or targeted temperature management (TTM)
as it is now more commonly known, has been
established for the post-resuscitation care of
OHCA since two pivotal studies in 2002. 4,5 In the
UK, it is incorporated into Resuscitation Council
guidelines as the fourth link in the chain of
survival (post-resuscitation care; Figure 1). This
was supported by the International Liaison
Committee on Resuscitation (ILCOR) in 2015. 6
This review aims to look at the theory behind
TTM and how it is applied clinically, with
attention to new research in this field and
what impact TTM has on patient survival
and neurological recovery.
Previous work and history
Hippocrates and the Persian army had already
commented on the protective nature of cold for
centuries before Napoleon’s chief surgeon,
Dominique Jean Larrey, documented that injured
soldiers kept closer to the fire died more
frequently than those kept away. 7 Studies from
the middle of the 20th century looked into MTH
following both severe head injury and cardiac
arrest, 8,9 but the results were uncertain and not
incorporated into standard practice.
Pivotal case reports exist of survival from
acute hypothermia with intact neurology,
possibly none more dramatic than that of Anna
Bagenholm, trapped under the ice in Norway for
80 minutes after a skiing accident in 1999, and
surviving to this day to work as a doctor. Her core
temperature was recorded at 13.7°C on arrival
at hospital, and her heart started after slow
rewarming on cardiac bypass. It is only in the
last 15–20 years that studies have progressed
to looking not only at survival rates post-OHCA
but also what degree of neurological deficit exists
after TTM is instigated.
Mechanism of protection
Understanding that the damage to the brain
occurs after cardiac arrest from hypoxia is
paramount. There is no substitute for early
recognition, early CPR and early defibrillation as
laid out by the Resuscitation Council to reduce
FIGURE 1
Chain of survival – Resuscitation Council
Early recognition
and call for help
To prevent cardiac
arrest
Early CPR
To buy time
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HHE 2019 | hospitalhealthcare.com
Early defibrillation
To restart the heart
Post resuscitation
care
To restore quality
of life