Contemporary animal models of cardiac arrest: A systematic review

Aim of the study Animal models are widely used in cardiac arrest research. This systematic review aimed to provide an overview of contemporary animal models of cardiac arrest. Methods Using a comprehensive research strategy, we searched PubMed and EMBASE from March 8, 2011 to March 8, 2016 for cardiac arrest animal models. Two investigators reviewed titles and abstracts for full text inclusion from which data were extracted according to pre-defined definitions. Results Search criteria yielded 1741 unique titles and abstracts of which 490 full articles were included. The most common animals used were pigs (52%) followed by rats (35%) and mice (6%). Studies favored males (52%) over females (16%); 17% of studies included both sexes, while 14% omitted to report on sex. The most common methods for induction of cardiac arrest were either electrically-induced ventricular fibrillation (54%), asphyxia (25%), or potassium (8%). The median no-flow time was 8 min (quartiles: 5, 8, range: 0–37 min). The majority of studies used adrenaline during resuscitation (64%), while bicarbonate (17%), vasopressin (8%) and other drugs were used less prevalently. In 53% of the studies, the post-cardiac arrest observation time was ≥24 h. Neurological function was an outcome in 48% of studies while 43% included assessment of a cardiac outcome. Conclusions Multiple animal models of cardiac arrest exist. The great heterogeneity of these models along with great variability in definitions and reporting make comparisons between studies difficult. There is a need for standardization of animal cardiac arrest research and reporting.