As highlighted by Chou et al[1] it is becoming more evident that extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (CPR) is feasible and compares well against conventional CPR. As technologies such as ECMO[2] and echocardiography (Echo),[3] previously limited to intensive care units and cardiology suites, become increasingly available in the Emergency Department (ED), it is important that we fully utilize the information and support they can provide to carefully select cardiac arrest patients for advanced ED resuscitation.

The percentage of patients who leave hospital alive following CPR varies from 0% to 20% and has not significantly improved in the last 30 years.[4] The recently published CHEER trial (mechanical CPR, Hypothermia, ECMO and Early Reperfusion), a single center, prospective, observational study from Australia, assessed the CHEER protocol, developed for selected patients with refractory in-hospital and out-of-hospital cardiac arrest.[5] The protocol involved mechanical CPR, induction of intra-arrest therapeutic hypothermia, early commencement of veno-arterial ECMO, and early coronary angiography for patients with suspected coronary artery occlusion. ECMO was established in 24 (92%) of 26 eligible patients, with a median time from collapse until initiation of ECMO of 56 min. Return of spontaneous circulation was achieved in 25 (96%) patients. Survival to hospital discharge with full neurological recovery occurred in 14/26 (54%) patients. Another study from the United States recently reported similar survival rates; 13 of 24 (54%) patients survived to hospital discharge with an ECMO based CPR protocol. Seven of these patients were discharged without any neurological deficit.[6] While these early results show promise for this form of advanced ED resuscitation, caution is required before rolling out this technology for all cardiac arrest patients.

Can our health care systems afford the increased requirement of intensive care bed-hours that such a policy would lead to? Can we select which patients are most likely to benefit from ED-ECMO?

A meta-analysis of predictors of survival from out-of-hospital cardiac arrest in 2010 found that survival to hospital discharge was more likely among those witnessed by a bystander or emergency medical services (EMS), those who received bystander CPR, were found in a shockable rhythm (VF/VT), or achieved return of spontaneous circulation (ROSC).[4] A further meta-analysis in 2012 looked at the of detection of cardiac activity on echo to predict survival during cardiac arrest. Pooled data showed that as a predictor of ROSC during cardiac arrest, echo had a pooled sensitivity of 91.6%, and specificity was 80.0%;[7] promising, but not independently predictive of survival.

Protocols including ED-ECMO are feasible and may be associated with a relatively high survival rate. The introduction of such protocols to emergency medicine should be encouraged, but must involve careful patient selection, optimizing survival benefit. This may involve bedside echo in the ED, as well as other demographic and clinically derived predictors of survival.

Paul R Atkinson, Professor in Emergency Medicine

Dalhousie University, Saint John Regional Hospital

1. Chou T.-H. An observational study of extracorporeal CPR for in- hospital cardiac arrest secondary to myocardial infarction. Emerg Med J 2014;31: 441-7.

2. Shinar Z, Bellezzo J, Paradis N, et al. Emergency department initiation of cardiopulmonary bypass: a case report and review of the literature. J Emerg Med. 2012;43(1):83-6.

3. Hayhurst C, Lebus C, Atkinson PR, et al. An evaluation of echo in life support (ELS): is it feasible? What does it add? Emerg Med J. 2011 Feb;28(2):119-21.

4. Stub D, Bernard S, Pellegrino V, et al. Refractory cardiac arrest treated with mechanical CPR, hypothermia, ECMO and early reperfusion (the CHEER trial). Resuscitation 2014. DOI: http://dx.doi.org/10.1016/j.resuscitation.2014.09.010.

5. Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors of survival from out-of-hospital cardiac arrest: a systematic review and meta- analysis. ?Circ Cardiovasc Qual Outcomes 2010;3:63-81.

6. Peigh G, Pitcher H, Cavarocchi N, Hirose H. Saving Life And Brain With Extracorporeal Cardiopulmonary Resuscitation (E-Cpr) Chest. 2014;146(4_MeetingAbstracts):722A. doi:10.1378/chest.1990723.

7. Blyth L, Atkinson P, Gadd K, Lang E. Bedside Focused Echocardiography as Predictor of Survival in Cardiac Arrest Patients: A Systematic Review. Acad Emerg Med 2012;19: 1119-1126.

Conflict of Interest:

None declared