Survival and neurological recovery after out-of-hospital cardiac arrest
Authors: Jarakovic M , Bjelica S , Kovacevic M , Petrovic M , Dimic S , Keca S , Dabovic D , Pantic T , Crnomarkovic B , Trajkovic M , Aleksic V 
Published: April 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Out-of-hospital cardiac arrest (OHCA) is a major public health challenge and although rate of intrahospital survival increased over the last 40 years, it still remains poor (from 8,6% in 1976-1999 to 9,9% in 2000-2019). Different studies report that introduction of mild therapeutic hypothermia (TTM) improves survival and neurological outcome in comatose patients after OHCA.

Purpose
The aim of this research was to evaluate influence of pre-hospital predictors related to cardiopulmonary resuscitation (CPR), neurological status and ECG changes at admission and early percutaneous coronary intervention (PCI) performed within 24h of admission on intrahospital survival and neurological outcome of OHCA patients.

Methods
The research was conducted as a retrospective cohort study of data taken from the hospital registry on OHCA from January 2007 until November 2019. The analyzed factors were: bystander CPR, duration of CPR until return of ROSC, initial rhythm, responsiveness upon admission defined as Glasgow Coma Score (GCS)&gt;8, presence of ST segment elevation (STEMI) on electrocardiography (ECG) and early PCI. The favorable neurological outcome was defined as a cerebral performance category scale (CPC)≤2.

Results
The research included 506 survivors of OHCA. Cardiac arrest was witnessed in 412 (81.4%), bystander CPR was performed in 197 (38.9%), CPR lasted ≤20min in 291 (57.5%), initial rhythm was shockable in 304 (60.1%) of patients. At admission 387 (76.5%) were comatose (GCS &lt; 8) and TTM was introduced in 177 (45.7%) of patients. ECG upon admission showed STEMI in 176 (34.8%) and early PCI was performed in 145 (28.6%) of patients. In-hospital mortality in our study group was 281 (55.5%) and 185 (36.6%) of patients had favorable neurological outcome. Multivariate regression analysis showed that initial shockable rhythm (OR 3.391 [2.310-4.977], p &lt; 0.0005), early PCI (OR 0.368 [0.226-0.599], p &lt; 0.0005), duration of CPR ≤20min (OR 4.249 [2.688-6.718], p &lt; 0.0005) and GCS &gt; 8 (OR 0.194 [0.110-0.343], p &lt; 0.0005) were independent predictors of in-hospital survival. Independent predictors of favorable neurological outcome were: initial shockable rhythm (OR 3.301 [2.002-5.441], p&lt; 0.0005), STEMI on ECG upon admission (OR 0.528 [0.326-0.853], p = 0.009), duration of CPR ≤20min (OR 5.144 [3.090-8.565], p&lt; 0.0005) and GCS &gt; 8 (OR 0.152 [0.088-0.260], p&lt; 0.0005). Introduction of TTM improved both intrahospital survival (54.1% vs. 24.4%; p &lt; 0.0005) and neurological outcome (33.5% vs. 11.6%; p &lt; 0.0005) in patients with initial shockable rhythm.

Conclusion
In our study group of OHCA patients of any origin, initial shockable rhythm, duration of CPR ≤20min and GCS &gt; 8 at admission influenced both intrahospital survival and favorable neurological outcome. Introduction of TTM significantly improved both survival and neurological outcome in comatose patients with initial shockable rhythm.