Studying the establishment of rat model of asphyxial cardiac arrest and the efficacy of CPR / 中华急诊医学杂志

ABSTRACT

Objective To study the establishment of rat model of asphyxia-cardiac arrest and efficacy of CPR in order to find the length of optimum time of asphyxia to cause injury.Methods One hundred and twenty-six male Sprague-Dawley rats were randomly (random number) divided into sham operation group and experimental groups.Cardiac arrest was induced by asphyxiation after intravenous injection of vecuronium bromide.The experimental groups were assigned into AP4 (four-minute asphyxia period),AP6 and AP8 subgroups in accordance with different lengths of time of asphyxia subjected to.In these groups,CPR,including pre-cordial compression and synchronized mechanical ventilation,was initiated 4,6 and 8 min after asphyxia-induced cardiac arrest,respectively.The successful ratio of resuscitation and hemodynamic variables were recorded.Brain water content,neural deficit scores (NDS),imaging changes on MR,pathological changes of brain tissue and neuronal apoptosis were evaluated at 1 d,3 d and 7 days after ROSC.All the data were analyzed by single-factor analysis of variance or Chi-square test.P ＜ 0.05 was considered statistically significant.Result The lowest NDS occurred at 1 d after ROSC,brain water content and imaging changes on MR were most obvious at 3 d after ROSC,while pathological changes of brain tissue and neuronal apoptosis increased and reached the peak at 7d after ROSC.The survival rates after 24 hours of AP4,AP6 and AP8 groups were 85％,75％ and 45％,respectively.The rate of ROSC and survival rate of AP8 group were significantly lower than those of other groups (P ＜0.01).The longer time of asphyxia the severer pathological changes of brain tissue,brain edema,neural deficit,and magnetic resonance imaging changes in all experimental groups.As compared to other groups,the brain damage index of AP8 group was most serious,while that of AP6 group was moderate.Conclusions The rat model following asphyxia-induced cardiac arrest and cardiopulmonary resuscitation was established successfully.From the evidence of survival rate and damage grade of brain tissue,asphyxia for 6 min may be the rational length of ischemic time in this model.