Clinical paperFavourable survival of in-hospital compared to out-of-hospital refractory cardiac arrest patients treated with extracorporeal membrane oxygenation: An Italian tertiary care centre experience☆
Introduction
Despite major efforts to reduce the outcomes of sudden death, including worldwide publication of new cardiopulmonary resuscitation (CPR) guidelines every 5–8 years for the past 4 decades, average survival rate from cardiac arrest (CA) remains dismal and presents a large variation, with a spread between 2% and 49%.1, 2, 3 Indeed, both short-term survival and survival to hospital discharge decrease with the duration of CPR. The rate of survival to hospital discharge decreases when CPR duration exceeds 10–15 min,4, 5 whereas patients resuscitated for longer than 30 min usually die in the intensive care unit (ICU).6
Accordingly, ‘refractory’ CA is defined by the lack of return to spontaneous circulation (ROSC) within a period of 30 min of CPR.7, 8 Extracorporeal membrane oxygenation (ECMO) is an aggressive and invasive method for extracorporeal CPR that has been suggested for refractory CA, with the goal of supporting the body's circulation in the absence of an adequately functioning cardiac pump.9 ECMO has been used in CA since 1976,10 after the introduction of battery-powered portable cardiopulmonary bypass machines. However, the use of this technique remained restricted for many years to patients presenting CA following an open heart surgery11 and to those undergoing accidental hypothermia12 and massive drug overdose.13 Recent developments in cardiopulmonary by-pass technology, such as miniaturised extracorporeal devices, heparin coated circuits and percutaneous cannulation techniques,14, 15, 16 have permitted a wider use of this support in different clinical situations.17 Recent studies have also highlighted the capability on the early application of ECMO to improve the prognosis of prolonged CA occurring both in in-hospital (IHCA)18 and out-of-hospital (OHCA) settings.18, 19 The rationale for use of ECMO in these patients is to optimise perfusion of vital organs while treating the cause of CA and/or waiting for the recovery of the injured myocardium.
In the present study, we have retrospectively evaluated the experience of our tertiary care centre on the use of ECMO in adult patients with refractory IHCA and OHCA. We have further examined outcome differences between IHCA and OHCA and factors accounting for such differences.
Section snippets
Patients
We retrospectively analysed our ECMO data registry of 42 patients treated with ECMO for refractory CA, at San Gerardo Hospital, from January 2006 to February 2011. The study was approved by our Institutional Review Board.
Inclusion and exclusion criteria
The activation of the ECMO team was considered for refractory CA patients in whom ROSC could not be achieved by conventional CPR. More specifically, CA was considered ‘refractory’ by the anaesthesiologist in charge of the resuscitative manoeuvres based on the following
Results
Our population consisted of 42 patients, 24 presented IHCA and 18 OHCA. ECMO implantation was successful in 38 patients (90%), while in four cannulation failure occurred, two in IHCA patients and two in OHCA patients. Main characteristics of the patients are shown in Table 1. OHCA patients presented a significantly higher median age and a prevalence of males compared to IHCA patients. The most common cause of CA was an acute coronary syndrome in both groups, followed by complications arising
Discussion
The present retrospective analyses on 42 patients presenting refractory CA and subjected to ECMO treatment have demonstrated that this approach might be beneficial for a group of patients in which a mortality close to 100% would have been otherwise expected.23 Patients suffering from refractory IHCA were objectively different from OHCA patients. First, they were on average older and suffered complex diseases. Some were post-cardiac surgery patients in which the CA occurred in the early
Conclusions
Our case series support the use of ECMO for IHCA. To increase the survival in OHCA patients, the ideal target of ECMO is the capability to achieve a restricted, close to zero, no-flow time with CPR immediately initiated by bystanders or the emergency medical services (EMS) and a reduction in low-flow time with early activation of the ECMO team.
Nevertheless, adequate organ perfusion could be accomplished by ECMO eventually allowing organ donation in those patients who do not achieve weaning off
Conflict of interest statement
None declared.
Acknowledgements
We appreciate the efforts of the cardiac surgical intensive care unit, emergency room and catheter laboratory nursing staff at S. Gerardo Hospital, which made this study possible.
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2011.10.013.