ABSTRACT
Objective To investigate the effect of epinephrine combined with methoxamedrine on rate of successful cardiopulmonary resuscitation (CPR) in rabbit model of sudden cardiac arrest by the method of clamping the trachea to asphyxia.Methods Twenty-seven rabbits were randomly (random number)divided into methoxamedrine group,epinephrine group and epinephrine combined with methoxamedrine group.After the modeling,rabbits in the three groups were treated methoxamedrine,epinephrine,and epinephrine combined with methoxamedrine respectively by intravenous injection during CPR.The change of heart rate (HR),mean arterial pressure (MAP) and electrocardiogram (ECG),restoration of spontaneous circulation (ROSC) and mortality within 2 hours of each experimental group were recorded before suffocation and 15 min,30 min,60 min,120 min after the success of the resuscitation.The pathological changes of myocardium were observed under optical and electronic microscope.Results The number of ROSC rabbits in methoxamedrine group,epinephrine group and epinephrine combined with methoxamedrine group were 1,6,5 respectively.The heart rate and mean arterial pressure of the rabbits after ROSC were lowered compared with those before suffocation significantly (P ＜0.05).The levels of mean arterial pressure at 15 minutes and 30 minutes after ROSC in combined treatment group were higher than those of epinephrine group significantly (P ＜ 0.05).The myocardial structure of rabbits after ROSC observed by optical and electronic microscope showed an acute injury,however,the damage degree of myocardium in combined treatment group was slighter.Conclusions Epinephrine combined with methoxamedrine has no apparently additional effect on ROSC during CPR compare with epinephrine used alone,but this combination of two agents can be benefit for stabilizing hemodynamic at early post-ROSC stage,and methoxamedrine can reduce the damage of myocardium during CPR.