Induced Moderate Hypothermia After Cardiac Arrest - American ...

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hour. Warming must be done slowly to prevent
complications, such as rebound hyperthermia,
which increases cerebral edema. Other complications
that may occur during warming include
seizures, VF, and hypotension. Fever is common
in the first 48 hours after the completion
of hypothermia treatment. This may be neurologically
mediated, inflammation, or infection
related. The risk of poor neurological outcome
is increased for each degree over 37C reached
in the post–cardiac arrest patient. 5,6,13,20,22
Hyperoxia should be avoided in this patient
population. Research has shown ventilation
with 100% oxygen in the first hour after
experimental cardiac arrest resulted in worse
neurological outcomes. 20 Excessive oxygen
harms postischemic neurons by causing excessive
oxidative stress in the early stages of
reperfusion. 20 Monitor and titrate oxygen
levels by using arterial blood gases and by continuous
saturation monitoring. 20
Quality of care is directly related to outcomes
for this patient population. It is vital that
standard ICU care, such as frequent turning,
oral care, use of ventilator bundles, head of bed
at 30º, strict input and output, sterile technique
when manipulating catheters, glucose level control,
peptic ulcer, and deep vein thrombosis prophylaxis,
be provided for all ICU patients but
especially for this patient population. 6
Protocol Development
The development of a standardized protocol or
order set should be considered before using
induced mild hypothermia following cardiac
arrest. One study indicated that temperature
goals for induced hypothermia could be reliably
achieved when a standardized order set was
used. 23 A protocol should identify the patient
population that is appropriate to receive the
treatment and direct care and assessments. Recommendations
from the AHA and published
research can be utilized to facilitate development
of the protocol. Using examples of order
sets from other institutions may be helpful. If a
particular device is going to be used for cooling,
the company’s experts may also assist in the
development of the order set. The remainder of
this article discusses what should be considered
when developing a protocol for induced
hypothermia following cardiac arrest.
The induced therapeutic mild hypothermia
post–cardiac arrest order set from Baylor University
Medical Center (BUMC) in Dallas,
Texas, is used as an example during this discussion
(Figure 3). A standardized protocol for
inducing mild hypothermia following cardiac
arrest was initiated in 2005. As more research
became available and lessons were learned
during use of the protocol, revisions were
made to reflect the new AHA recommendations
and research. The protocol was also
revised to provide clarity to the health care
team in caring for these patients and answer
questions that were raised with the use of the
initial protocol.
Inclusion and exclusion criteria were developed
based on the 2 studies published by
Bernard 7 and the Hypothermia After Cardiac
Arrest Study Group, 8 the AHA recommendations,
1 ILCOR recommendations, 11 and lessons
learned during use of the initial protocol. The
inclusion and exclusion criteria are detailed in
the protocol to assist the health care team to
identify appropriate patients.
Identification of Appropriate
Patients for Induced Hypothermia
At BUMC, all unconscious, post–cardiac arrest
patients with ROSC whose arrest was believed
to be of cardiac origin are considered for
induced hypothermia. It is an AHA class IIa
recommendation that all unconscious patients
with ROSC after out-of-hospital VF cardiac
arrests receive induced hypothermia. 1 The
AHA also recommends that induced hypothermia
may be beneficial in non-VF arrests for
out-of-hospital or in-hospital arrests. 1 Bernard
et al 7 and the Hypothermia After Cardiac
Arrest Study Group 8 excluded patients who
experienced cardiac arrests of noncardiac etiology,
such as respiratory failure, from their clinical
trials. 7,8,11 Therefore, cardiac arrests of
noncardiac etiology are excluded at BUMC
until future studies are completed.
Following the Hypothermia After Cardiac
Arrest Study Group 8 study design, only those
patients with cardiac arrests that are witnessed
with less than 15 minutes to the first attempt
of resuscitation and ROSC in less than 60 minutes
are considered for this protocol. 8 Patients
who are unable to maintain a systolic blood
pressure of 90 mm Hg despite intravenous
fluids or vasopressors are also not considered
as candidates. 7,8
One of the inclusion criteria on the initial
protocol was coma without a definition. It was
found that the health care team had different
definitions of coma. For this protocol, coma was
defined as “coma suggested by the following:
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