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Abstract

Abbreviations: CPR, cardiopulmonary resuscitation; ROSC, resumption of spontenaeous circulation; VF, ventricular fibrillation IntroductionCardiac arrest is an important public health issue in humans in industrialized countries with, e.g., 35,000 to 40,000 new cases each year in France.1,2 Despite increasing implementation of cardiopulmonary resuscitation (CPR) in the field, resumption of spontaneous circulation (ROSC) is typically obtained in less than 35% of these patients. Resuscitated victims often present a post cardiac arrest syndrome with a complex physiopathology combining hemodynamic failure, neurological dysfunction and multi-visceral injury, leading to an additional worsening of the prognosis. Ultimately, less than 8% of the patients survive with favorable neurological function at hospital discharge. [3][4][5] In this context, experimental research is crucial to provide new therapeutic approaches increasing CPR efficiency and initial resuscitation, as well as long term prognosis and neurological recovery. For such investigations, the use of animal models seems unavoidable as cardiac arrest provokes multiple visceral consequences as well as inflammatory response and coagulopathy. These models allow not only a better understanding of the pathophysiology but also the investigation of new treatment strategies to improve CPR efficiency or prevent multi-organ failure. This field of research can also address fundamental questions for veterinary research, beyond the relevance for human medicine. Impact of species-differencesIn general, animal models of cardiac arrest are using rodents, rabbits, pigs or dogs. All these species present anatomical or physiological specificities that should been considered in the design of the study, depending upon the specific goals and corresponding end-points. Cardiac arrest in rodentsAs usual in biomedical research, rodents are widely used in resuscitation sciences due to their relative ease of manipulation, low cost and extensive possibilities of mechanistic investigations with genetically modified animals. Obviously, this use is associated with several limitations related to their cardiovascular anatomy and physiology. On the one hand, rodents present two different cranial venae cavae (right and left) with a coronary sinus formed by the proximal part of the left cranial vena cava.6 This directly modifies the coronary perfusion during cardiac massage through different venous return as compared to large animals.7 In addition, due to their very low body mass, cardiac massage could make blood circulating through direct heart compression, while it is mostly acting through thoracic pumping in large animals. On the other hand, spontaneous heart rate is much higher in rodents than in large animals and humans as usual values average 260-450 or 500-600 beats per minute in awake rats and mice, respectively. 7,8 This directly impacts the required chest compression rate in those species as mice should undergo ≈400 compressions per min to be resuscitated. [9][10][11][12][13][14] Magnetic ...