title: Extracorporeal resuscitation for refractory out-of-hospital cardiac arrest in adults: A systematic review of international practices and outcomes.
abstract: OBJECTIVE
  Extracorporeal resuscitation during cardiopulmonary resuscitation (ECPR) deploys rapid cardiopulmonary bypass to sustain oxygenated circulation until the return of spontaneous circulation (ROSC). The purpose of this systematic review is to address the defining elements and outcomes (quality survival and organ donation) of currently active protocols for ECPR in refractory out-of-hospital cardiac arrest (OHCA) of cardiac origin in adult patients. The results may inform policy and practices for ECPR and help clarify the corrresponding intersection with deceased organ donation.
  
  
  METHODS
  We searched Medline, Embase, Cochrane and seven other electronic databases from 2005 to 2015, with no language restrictions. Internal validity and the quality of the studies reporting outcomes and guidelines were assessed. The review was included in the international prospective register of systematic reviews (Prospero, CRD42014015259).
  
  
  RESULTS
  One guideline and 20 outcome studies were analyzed. Half of the studies were prospective observational studies assessed to be of fair to good methodological quality. The remainder were retrospective cohorts, case series, and case studies. Ages ranged from 16 to 75 years and initial shockable cardiac rhythms, witnessed events, and a reversible primary cause of cardiac arrest were considered favorable prognostic factors. CPR duration and time to hospital cannulation varied considerably. Coronary revascularization, hemodynamic interventions and targeted temperature management neuroprotection were variable. A total of 833 patients receiving this ECPR approach had an overall reported survival rate of 22%, including 13% with good neurological recovery. Additionally, 88 potential and 17 actual deceased organ donors were identified among the non-survivor population in 8 out of 20 included studies. Study heterogeneity precluded a meta-analysis preventing any meaningful comparison between protocols, interventions and outcomes.
  
  
  CONCLUSIONS
  ECPR is feasible for refractory OHCA of cardiac origin in adult patients. It may enable neurologically good survival in selected patients, who practically have no other alternative in order to save their lives with quality of life, and contribute to organ donation in those who die. Large, prospective studies are required to clarify patient selection, modifiable outcome variables, risk-benefit and cost-effectiveness.
authors.affiliation: Canadian National Transplant Research Program, Canada; Research Institute McGill University Health Centre, Montréal, Canada; Centre de Prélèvement d'Organes and Laboratoire de Simulation, Hôpital du Sacré-Cœur, Montréal, Canada; Faculty of Medicine and Health Sciences, Universidad de Alcalá de Henares, Madrid, Spain; Helicopter Emergency Medical Service (SUMMA 112), Madrid, Spain. Electronic address: iviortega@gmail.com.
authors.forename: Iván
authors.initials: I
authors.lastname: Ortega-Deballon
authors.affiliation: DePPaRT Study, Pediatric Critical Care, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada; Deceased Donation, Canadian Blood Services, Ottawa, Canada. Electronic address: lhornby@uottawa.ca.
authors.forename: Laura
authors.initials: L
authors.lastname: Hornby
authors.affiliation: Deceased Donation, Canadian Blood Services, Ottawa, Canada; Division of Critical Care, Montreal Children's Hospital, McGill University Health Centre, Montreal, Canada; McGill University, Montreal, Canada. Electronic address: sam.shemie@mcgill.ca.
authors.forename: Sam D
authors.initials: SD
authors.lastname: Shemie
authors.affiliation: Division of Critical Care, Montreal Children's Hospital, McGill University Health Centre, Montreal, Canada; McGill University, Montreal, Canada; Royal College of Physicians and Surgeons of Canada, Canada. Electronic address: farhan.bhanji@mcgill.ca.
authors.forename: Farhan
authors.initials: F
authors.lastname: Bhanji
authors.affiliation: Medical Library, McConnell Resource Centre, McGill University Health Centre, Montreal, Canada. Electronic address: elena.guadagno@muhc.mcgill.ca.
authors.forename: Elena
authors.initials: E
authors.lastname: Guadagno
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D017410:Practice Guidelines as Topic; D015996:Survival Rate; D009927:Tissue and Organ Procurement; D055815:Young Adult
keywords: Anoxic brain injury; Cardiopulmonary resuscitation; Deceased organ donation; Extracorporeal resuscitation; Out-of-hospital cardiac arrest; Refractory cardiac arrest