In-hospital versus out-of-hospital cardiac arrest: Characteristics and outcomes in patients admitted to intensive care after return of spontaneous circulation

Introduction: Cardiac arrest is characterized depending on location as in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA). Strategies for Post Cardiac Arrest Care were developed based on evidence from OHCA. The aim of this study was to compare characteristics and outcomes in patients admitted to intensive care after IHCA and OHCA.

Methods: A retrospective multicenter observational study of adult survivors of cardiac arrest admitted to intensive care in southern Sweden between 2014-2018. Data was collected from registries and medical notes. The primary outcome was neurological outcome according to the Cerebral Performance Category (CPC) scale at 2-6 months.

Results: 799 patients were included, 245 IHCA and 554 OHCA. IHCA patients were older, less frequently male and less frequently without comorbidity. In IHCA the first recorded rhythm was more often non-shockable, all delay-times (ROSC, no-flow, low-flow, time to advanced life support) were shorter and a cardiac cause of the arrest was less common. Good long-term neurological outcome was more common after IHCA than OHCA. In multivariable analysis, witnessed arrest, age, shorter arrest duration (no-flow and low-flow times), low lactate, shockable rhythm, and a cardiac cause were all independent predictors of good long-term neurological outcome whereas location of arrest (IHCA vs OHCA) was not.

Conclusion: In patients admitted to intensive care after cardiac arrest, patients who suffered IHCA vs OHCA differed in demographics, co-morbidities, cardiac arrest characteristics and outcomes. In multivariable analyses, cardiac arrest characteristics were independent predictors of outcome, whereas location of arrest (IHCA vs OHCA) was not.