A Comparative Study Between a Pre-hospital and an In-hospital Circulatory Support Strategy (ECMO) in Refractory Cardiac Arrest

1 STATUS OF THE QUESTION 2.1 Circumstances surrounding the problem: 2.1.1 The limits of conventional resuscitation in cardiac arrests. Sudden adult death, unexpected cardiac arrest (CA) most often related to cardiovascular causes, affects more than 40,000 people in France every year.

The prognosis of out-of-hospital sudden death is particularly sombre. Only 5 to 20% of the patients survive without neurological sequel. This prognosis can be partially improved by an efficient organization of management that implements the concept of the "survival chain". An early alert by witnesses of the CA, carrying out the first interventions, cardiopulmonary resuscitation (CPR), defibrillation by the public or persons qualified in first-aid, followed by specialized resuscitation by a medical team (such as the ambulance service) increase the amount of survivors. The reduction in the time that passes before the first interventions (called the no-flow period) and the duration of resuscitation before return of spontaneous circulation (ROSC) called low-flow, are considered to be the primary predictive factors of survival in CA.

Just recently, better knowledge of post-cardiac arrest syndrome also contributed to an improvement in the prognosis and the quality of survival. The introduction of early angioplasty and the generalisation of therapeutic hypothermia now complete management for which coding is steadily improving through international and national recommendations that are updated every 5 years. However, in order to show what it is capable of, this conventional management of CA requires spontaneous cardiac activity to be re-established as quickly as possible. Therefore, a return of spontaneous circulation (ROSC) must be obtained in the field in out-of-hospital sudden deaths.

Classically, in the absence of ROSC after 30 minutes of correctly administered resuscitation, the CA is considered to be refractory and the treatment options are limited. Just recently, it was shown that the chances of survival are non-existent after 16 minutes of resuscitation. In most cases, resuscitation is discontinued and the patient is declared dead on the spot. The regulatory inclusion of a physician on ambulance service teams relieves the difficulty of this decision. It is often simple to make and is medically indisputable when it is obvious that the prognostic factors are very unfavorable (notably, an extended no-flow period) and/or the conditions (advanced age, severe chronic disease, etc...) are not compatible with prolonged resuscitation. This decision is much more difficult when the prognostic factors are favorable and prolonged resuscitation efficiently provides spontaneous circulation (signs of the patient awaking during CPR). Under these circumstances, in France and several other European countries, the decision can be made to continue extracorporeal membrane oxygenation (ECMO) and transport the refractory CA victim. It was made possible by the development of mechanical external cardiac massage devices such as Autopulse ® and Lucas® which enable prolonged cardiac compression during transport by the emergency service. However, this continuation of resuscitation can only be considered if it enables another subsequent treatment for the patient. Two options are possible. The patient can be declared dead and become a potential organ donor in the framework of an organ harvesting procedure in a patient after "cardiac death". This harvesting, which is highly organized according to regulations, can only be done in certain hospitals authorized by the French Biomedicine Agency.

Or, resuscitation can be prolonged by the use of extracorporeal circulatory support.