BC ECPR Trial for Out-of-Hospital Cardiac Arrest

The addition of an Extracorporeal-Cardiopulmonary Resuscitation (ECPR) service to a region may improve the survival of young patients with sudden unexpected cardiac arrest.The primary aim of this study is to determine the benefit of the systematic integration of ECPR services into the out-of-hospital cardiac arrest management algorithm. The investigators will compare the outcomes of ECPR-eligible patients in the intervention region, in comparison to patients meeting the same criteria in a comparable setting.

British Columbia is a province which contains four metropolitan areas, each of which contains at least one tertiary care centre that provides Extracorporeal Membrane Oxygenation (ECMO) and cardiovascular surgery services, in addition to critical cardiology services and a coronary catheterization laboratory. Pre-hospital medical care in all areas is provided by British Columbia Emergency Health Services (BCEHS), which uses a tiered system of basic life support and advanced life support (ALS) paramedics (90% of cases have ALS involvement) in coordination with fire department first responders. Medical providers in the study footprint have extensive experience with interventional trials enrolling patients with out-of-hospital cardiac arrest, through participation in the Resuscitation Outcomes Consortium.

Through collaboration of clinicians from all areas and with BCEHS, this study will examine the benefit of a regional ECPR protocol established in one of the metropolitan areas (the "ECPR Protocol Region"), in comparison to the other areas (the "Usual Care Region"). The primary aim is to determine the benefit of incorporating ECPR services into a regional medical system of care for out-of-hospital cardiac arrest. All patients with out-of-hospital cardiac arrest treated by emergency medical services (EMS) in both regions will be prospectively evaluated for study eligibility.

Secondary aims include:

1. To evaluate the effectiveness of ECPR therapy for those with refractory cardiac arrest after 45 minutes of attempted resuscitation.
2. To evaluate the effectiveness of a regional ECPR protocol, in comparison to historical controls.
3. To evaluate the long-term (5-year) outcomes of patients treated with ECPR.
4. To evaluate the quantity of successful organ procurement from those treated with ECPR.
5. To evaluate the cost-effectiveness of a regional ECPR protocol.

This study is a parallel group design with group allocation based on region of treatment. The investigators will compare the outcomes of ECPR-eligible patients in the intervention region, in comparison to patients meeting the same criteria in a comparable setting (the control regions group). Medical care in the control regions will be unaltered by this study.

Group outcomes will be compared. The association of treatment group and outcomes will also be assessed using a logistic regression analysis, while adjusting for other important prognosticators in out-of-hospital cardiac arrest (including initial cardiac rhythm, time to emergency medical services \[EMS\] arrival, bystander cardiopulmonary resuscitation \[CPR\], EMS-witnessed arrest, and age).

Eligibility Criteria:
The study evaluates the outcomes of those treated with an ECPR protocol, in comparison to patients in the control region meeting the same criteria. The following is the regional ECPR eligibility criteria:

Inclusion Criteria:

1. Intra-arrest treatment by an ALS paramedic
2. Age ≥ 18 and ≤ 65 years
3. Witnessed arrest
4. Bystander CPR required if initial rhythm is pulseless electrical activity (added to the protocol June, 2018 and applied retrospectively)
5. Cause of the arrest is presumed to be one of the following:

   * No obvious non-cardiac cause is identified
   * Known overdose of one of the following drugs: beta-blocker, calcium channel blocker, tricyclic antidepressants or other psychiatric medications, or digoxin
   * Hypothermia (with T \< 32°C)

(5) The patient remains pulseless after a minimum of 3 cycles of CPR (by any professional provider).

Exclusion Criteria:

1. An alternate cause of the arrest is most likely
2. Do Not Resuscitate status
3. Co-morbidities including congestive heart failure, chronic obstructive pulmonary disease or other significant lung disease, dialysis, liver failure (if co-morbidities are unknown to paramedics they will be assumed not present)
4. Active malignancy
5. Pre-existing major neurological deficit
6. Asystole (added to the protocol June, 2018 and applied retrospectively)