Extracorporeal cardiopulmonary resuscitation for in- and out-of-hospital cardiac arrest: The race against time

Extracorporeal cardiopulmonary resuscitation (ECPR) is increasingly used due to its beneficial outcomes and results compared to conventional CPR. Cardiac arrests can be categorized depending on location: in-hospital cardiac arrest (IHCA) and out-of-hospital cardiac arrest (OHCA). Despite this distinction, studies comparing the two are scarce, especially in comparing outcomes after ECPR. This study compared patient characteristics, cardiac arrest characteristics, and outcomes. Between 2016 and 2022, patients who underwent ECPR for cardiac arrest at our institution were retrospectively analyzed, depending on the arrest location: IHCA and OHCA. We compared periprocedural characteristics and used multinomial regression analysis to indicate parameters contributing to a favorable outcome. A total of n = 157 patients (100%) were analyzed (OHCA = 91; IHCA = 66). Upon admission, OHCA patients were younger (53.2 ± 12.4 vs. 59.2 ± 12.6 years) and predominantly male (91.1% vs. 66.7%, p=<0.001). The low-flow time was significantly shorter in IHCA patients (41.1 ± 27.4 mins) compared to OHCA (63.6 ± 25.1 mins). Despite this significant difference, in-hospital mortality was not significantly different in both groups (IHCA = 72.7% vs. OHCA = 76.9%, p = 0.31). Both groups' survival-to-discharge factors were CPR duration, low flow time, and lactate values upon ECMO initiation. Survival-to-discharge for ECPR in IHCA and OHCA was around 25%, and there was no statistically significant difference between the two cohorts. Factors predicting survival were lower lactate levels before cannulation and lower low-flow time. As such, OHCA patients seem to tolerate longer low-flow times and thus metabolic impairments compared to IHCA patients and may be considered for ECMO cannulation on a broader time span than IHCA.