Page 697 - ACCCN's Critical Care Nursing

Research vignette, Continued
Critique Performance Category (CPC). This scale rates patients from 1
The use of therapeutic hypothermia as a modality to improve (normal) through to 5 (certified brain-dead) and has been used as
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mortality and morbidity in out of hospital cardiac arrest has been a comparable outcome measure in similar recent studies. This
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well recognised in the literature since 2002. The International study noted that 31 percent of participants had a CPC score of 1
Liaison Committee on Resuscitation (ILCOR) published an advisory or 2. While the Australian experience has not been discussed,
statement in 2003 recommending the implementation of thera- generalisation to the Australian context should be made with
peutic hypothermia. The American Heart Association (AHA) and caution.
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the European Resuscitation Council (ERC) also published thera- Whilst the researchers claim that their modality of therapeutic
peutic hypothermia guidelines following the ILCOR 2005 con- hypothermia is rapid, safe and low cost, they highlight that the
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sensus on science and treatment recommendations, and these major barrier inhibiting the uptake of this treatment is technical
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were updated and republished in 2010. However, as pointed difficulties. The researchers attribute these difficulties to the cost
out in this paper, the uptake of therapeutic hypothermia across of commercial equipment required to rapidly and effectively
the world has been slow and reasons for this have included the implement therapeutic hypothermia. This cost is underexplored in
cost of equipment used for cooling. 151-156 When referring to these this study; it is eluded that all devices are expensive and therefore
statements of utilisation, the reader should be aware that the unattainable by many hospitals. The researchers then state that
Australian experience has not been discussed and therefore gen- their method is labour -intensive, however the cost comparison of
eralisation of the Australian context cannot be made. Further, the labour as opposed to use of the various devices is not explored.
as the authors note, the use of a single study site limits the The insertion and confirmation of nasograstric tube (NGT) occurred
generalisability of the findings.
by auscultation and aspiration of gastric fluid. Evidence cautions
The ILCOR statement on therapeutic hypothermia states that intra- against the use of litmus paper, auscultation and bubbling to
venous ice cold fluids (30 mL/kg) can safely initiate therapeutic confirm NGT placement, with pH testing and X-ray confirmation
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hypothermia and the use of ice packs and/or cooling blankets and preferred. Thus, the reader should be aware that the use of ice-
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pads can maintain temperature control. In this study, therapeutic water gastric lavage is not supported by ILCOR and that there are
hypothermia was initiated at 40 mL/kg; the authors do not state inherent risks of NGT misplacement. Replication of the study
why they used a higher fluid volume than recommended by ILCOR. without the ice-water gastric lavage cooling technique will likely
Similarly, the use of ice-water gastric lavage in the study has not be beneficial.
been recommended by ILCOR. Other reported methods of non- The benefits of initiating mild therapeutic hypothermia following
invasive cooling not recommended by ILCOR, but evident in the an OHCA or IHCA are well documented in the literature. The
literature, includes the trans-nasal insertion of an evaporative authors rightly note that transferring this evidence into practice
coolant into the nasopharynx. 157-159
has not been seen and cite the ease of cooling processes as
Various methods have been documented for recording and moni- its potential barrier. In the study, the researchers report a redu-
toring the core temperature, including involving the bladder, ction in the ROSC to initiation of hypothermia time (257 to 132
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rectum, pulmonary artery and oesophagus. While pulmonary minutes) with targeted education, raising clinical awareness
artery catheters are considered to be ‘gold standard’, the use of through lectures and wide distribution of cooling protocols.
minimally-invasive monitoring such as oesophageal temperature Other studies have also found an increase in the therapeutic
monitoring is considered to be optimal. Temperature monitor- hypothermia following the implementation of a standardised
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ing using the bladder and the rectum should be interim measures protocol. 162,163
only as there is typically is a ‘temperature lag time’ behind the core
temperature. In addition, variability of measurements occurs with The mix of patients in this study also needs consideration. Defini-
the flow of urine presence and faeces around the catheter. Con- tive data on benefit has been primarily based on out-of-hospital
sistent with ILCOR recommendations, re-warming commenced cardiac arrest (OHCA) with ILCOR only highlighting two studies
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after 24 hours, however the authors state that the recommended that included both OHCA and in-hospital cardiac arrests (IHCA).
rate is no more than 0.5 °C/h. ILCOR makes no mention of the rate The researchers in this study had predominately IHCA patients
of rewarming and the researchers reference this rate to Scandina- (n = 40) whereas OHCA patients were of lower numbers (n =
vian Clinical Practice. The researchers in the study achieved a 25). This study is important as it adds weight to the supportive
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re-warming rate of 0.18 °C/h. evidence for therapeutic hypothermia for all patients suffering
cardiac arrest who remain comatose post return of spontaneous
Cognitive preservation was measured as an outcome measure circulation. Interestingly the IHCA group had better neurological
in the current study using the Glasgow-Pittsburg Cerebral outcomes overall when compared with the OHCA group.

Learning activities

All learning activities relate to the case study. 4. Discuss the pathophysiology of PEA in relation to the case
1. Discuss the management of this patient in relation to the ALS study.
flowchart. 5. Outline the role of therapeutic hypothermia in post arrest care.
2. Discuss the ethical issues of consent and limitations of treat- 6. Outline the postresuscitation management that is related to
ment as related to the case study. this case study.
3. Identify potential causes of PEA.