A contemporary subgroup analysis of cooling after non-shockable cardiac arrest: Insights from a large registry - PROJECT SUMMARY
Since 2005, therapeutic hypothermia/targeted temperature management (TH/TTM) has been recommended
for comatose patients recovering from out-of-hospital cardiac arrest (OHCA) due to a shockable first
documented rhythm in an attempt to attenuate reperfusion injury, preserve neurological function, and improve
long-term survival. After more than a decade of availability, the appropriate application of TH/TTM after non-
shockable OHCA, to maximize neurologically intact survival and avoid harm, has not yet been defined. Our
research is aimed at filling this knowledge gap. Our central hypothesis, based on our preliminary data, is that
TH/TTM outcomes, compared with normal treatment (NT), will vary by rhythm classification. The scientific
premise for performing this study is that, without any convincing evidence, TH/TTM has been extrapolated
beyond its proven indication to a group of patients in whom, for some, it may actually cause harm. From the
Cardiac Arrest Registry to Enhance Survival (CARES) dataset, we will compare neurological status at
hospital discharge between two treatment groups (TH/TTM and NT) to determine if the effect of TH/TTM is
modified by three presenting rhythm categories – initially shockable (IS), pulseless electrical activity (PEA),
and asystole. We will also compare neurological status at hospital discharge between two treatment groups
(TH/TTM and NT) to determine if the effect of TH/TTM in the group with first recorded rhythm of PEA or
asystole is modified by conversion to a shockable rhythm during attempted resuscitation (converted
shockable [CS] vs. never shockable [NS] rhythms). This research is significant because it will generate the
largest, most robust analysis of TH/TTM in non-shockable OHCA event survivors ever reported and
innovative in that we seek to alter current research and clinical practice paradigms by challenging the
conceptual framework that all non-shockable OHCA patients (PEA [CS and NS] and asystole [CS and NS])
should be grouped together when evaluating and applying TH/TTM as a neuroprotectant. The results
generated from this study are expected to more clearly define the appropriate use of TH/TTM in patients
recovering from OHCA due to an initially non-shockable rhythm, and thereby advance the NHLBI mission to
enhance the health of individuals so that they can live longer and more fulfilling lives.
