Extracorporeal cardiopulmonary resuscitation: a comparison of two experimental approaches and systematic review of experimental models

In patients requiring extracorporeal cardiopulmonary resuscitation (ECPR), there is a need for studies to assess the potential benefits of therapeutic interventions to improve survival and reduce hypoxic-ischemic brain injuries. However, conducting human studies may be challenging. This study aimed to describe two experimental models developed in our laboratory and to conduct a systematic review of existing animal models of ECPR reported in the literature. In our experiments, pigs were subjected to 12 min (model 1) or 5 min (model 2) of untreated ventricular fibrillation, followed by 18 min (model 1) or 25 min (model 2) of conventional cardiopulmonary resuscitation. Results showed severe distributive shock, decreased brain oxygen pressure and increased intracranial pressure, with model 1 displaying more pronounced brain perfusion impairment. A systematic review of 52 studies, mostly conducted on pigs, revealed heterogeneity in cardiac arrest induction methods, cardiopulmonary resuscitation strategies, and evaluated outcomes. This review emphasizes the significant impact of no-flow and low-flow durations on brain injury severity following ECPR. However, the diversity in experimental models hinders direct comparisons, urging the standardization of ECPR models to enhance consistency and comparability across studies.