Neurological outcomes and duration from cardiac arrest to the initiation of extracorporeal membrane oxygenation in patients with out-of-hospital cardiac arrest: a retrospective study

Abstract

BackgroundWe investigated the relationship between neurological outcomes and duration from cardiac arrest (CA) to the initiation of extracorporeal membrane oxygenation (ECMO) (CA-to-ECMO) in patients with out-of-hospital cardiac arrest (OHCA) treated with extracorporeal cardiopulmonary resuscitation (ECPR) and determined the ideal time at which ECPR should be performed.MethodsDuring the time period in which this study was conducted, 3451 patients experienced OHCA. This study finally included 79 patients aged 18 years or older whose OHCA had been witnessed and who underwent ECPR in the emergency room between January 2011 and December 2015. Our primary endpoint was survival to hospital discharge with good neurological outcomes (a cerebral performance category of 1 or 2).ResultsOf the 79 patients included, 11 had good neurological outcomes. The median duration from CA-to-ECMO was significantly shorter in the good neurological outcome group (33 min, interquartile range [IQR], 27–50 vs. 46 min, IQR, 42–56: p = 0.03). After controlling for potential confounders, we found that the adjusted odds ratio of CA-to-ECMO time for a good neurological outcome was 0.92 (95% confidence interval: 0.87–0.98, p = 0.007). The area under the receiver operating characteristic curve of CA-to-ECMO for predicting a good neurological outcome was 0.71, and the optimal CA-to-ECMO cutoff time was 40 min. The dynamic probability of survival with good neurological outcomes based on CA-to-ECMO time showed that the survival rate with good neurological outcome decreased abruptly from over 30% to approximately 15% when the CA-to-ECMO time exceeded 40 min.DiscussionIn this study, CA-to-ECMO time was significantly shorter among patients with good neurological outcomes, and significantly associated with good neurological outcomes at hospital discharge. In addition, the probability of survival with good neurological outcome decreased when the CA-to-ECMO time exceeded 40 minutes. The indication for ECPR for patients with OHCA should include several factors. However, the duration of CPR before the initiation of ECMO is a key factor and an independent factor for good neurological outcomes in patients with OHCA treated with ECPR. Therefore, the upper limit of CA-to-ECMO time should be inevitably included in the indication for ECPR for patients with OHCA. In the present study, there was a large difference in the rate of survival to hospital discharge with good neurological outcome between the patients with a CA-to-ECMO time within 40 minutes and those whose time was over 40 minutes. Based on the present study, the time limit of the duration of CPR before the initiation of ECMO might be around 40 minutes. We should consider ECPR in patients with OHCA if they are relatively young, have a witness and no terminal disease, and the initiation of ECMO is presumed to be within this time period.ConclusionsThe duration from CA-to-ECMO was significantly associated with good neurological outcomes. The indication for patients with OHCA should include a criterion for the ...

Prehospital extracorporeal cardiopulmonary resuscitation for out‐of‐hospital cardiac arrest: A retrospective eligibility study

“…Several studies have sought to determine the factors associated with positive outcomes from ECPR, with varying results. While there is considerable prognostic factor heterogeneity between studies, a short ‘low flow time’, and an initial shockable rhythm, were most consistently associated with improved outcomes . Prehospital ECPR initiation potentially minimises this circulatory low flow time and has also been associated with significantly increased rates of ROSC .…”

“…Group 3 also included those who presented in asystole who then developed a shockable rhythm at the next rhythm check. While there is a paucity of literature concerning ECPR in patients with a shockable second rhythm, two studies identified that any ROSC event, or transient ROSC, before ECPR, predicted favourable outcomes. This was reflected in the inclusion of non‐sustained ROSC as an alternative second rhythm in Group 3 inclusion criteria.…”

“…Group 2 included patients with an initial rhythm of PEA, as some studies have found this rhythm to be a prognostic indicator of survival, and SAMU de Paris have now included this rhythm in a prehospital ECPR protocol . Two studies found no association between bystander CPR and positive ECPR outcomes, and the effect of age and gender appears unclear, so on these criteria, our hypothetical ECPR criteria were relatively unrestrictive.…”

“…While non‐shockable rhythms have often been excluded from ECPR protocols, SAMU de Paris have now included PEA in a prehospital ECPR protocol, and some studies have found this initial rhythm to be a prognostic indicator of survival . Group 3 patients did not satisfy Group 1 or 2 inclusion criteria but had some characteristics that have been associated with positive outcomes after ECPR, such as initial shockable rhythm or transient ROSC . Patients were included in Group 3 if they had either an initial shockable rhythm where the rhythm became non‐shockable or non‐sustained ROSC before three shocks were delivered, or if they had an initial rhythm of asystole and the subsequent rhythm was shockable or non‐sustained ROSC.…”

“…Many factors could account for this outcome variation including heterogeneity of health systems, populations, interventions and follow up . While ECPR is promising, appropriate patient selection, optimal timing and cost‐effectiveness remain uncertain; although a shorter ‘low‐flow’ time, the CPR duration before ECPR initiation has been found to be associated with survival and positive neurological outcomes . While prehospital ECPR has been found to be feasible, safe and effective, it has yet to show a survival advantage over hospital initiated ECPR for OOHCA, despite being associated with significantly increased rates of return of spontaneous circulation (ROSC) and shorter periods of circulatory low‐flow …”