Bolus Doses And Continuous Infusion Of Epinephrine Effect On Hemodynamics And Cerebral Circulation Perfusion In Ventricular Fibrillation Rabbits

Objective:To study the effects of continuously administered epinephrine(Epi) with computer micro pump, compared to intermittent bolus doses, on hemodynamic and cerebral circulation perfusion in ventricular fibrillation rabbits during cardiopulmonary resuscitation (CPR) .Methods:Two of 22 rabbits were served as sham operated group ,which were not induced ventricular fibrillation and implemented of CPR .Other animals were randomized into two groups. A group was received an initial bolus of 20μg/kg epinephrine followed by an infusion of 10μg/kg/min epinephrine for 9 minutes. B group was received a bolus of 20μg/kg epinephrine every other 3 minutes, to amount to 4 times. Ventricular fibrillation was induced with epicardium electric current shock in 20 anaesthetised rabbits. aortic systolic pressure(ASP) ,aortic diastolic pressure (AOD),mean arterial pressure(MAP),central venous pressure(CVP),intracranial pressure(ICP) was measured. coronary perfusion pressure(CoPP), cerebral perfusion pressure(CePP),restoration of spontaneous circulation (ROSC) was calculated. The cerebral microcirculation perfusion was markded by injection of 0.3/kg 10% fluorescent isothiocyanate- albumin(FITC) after ROSC 30 minutes and the animals were decapitated 30 minutes later. At different levels three slices of the rabbit brain were observaed using 100 times fluorescence microscopy.Capillary filling with FITC areas were identified and calculated,quantified using image processing software IMAGEJ.Results:The data were analyzed with SPSS 11.5 statistical software, Group A was higher than Group B in ASP,AOD,MAP,CoPP,CePP (they had no difference between two groups before ventricular fibrillation). CoPP and CePP had difference (P<0.05) , a continuous epinephrine infusion compared with repeated bolus doses. 8 of 10 animals could survive to the end of the experimental in A group, while 6 of 10 animals could survive to the end of the experimental in B group. According to Fisher exact propability, rate of ROSC had no difference between two groups(p=0.628,p>0.05). the difference of the cerebral perfusion area (P<0.01)was also significant between A group(62.35±3.51%) and B group (31.92±3.86%).The two sham operated animals showed homogeneous cerebral microcirculation perfusion.Conclusions:Continuous infusion of epinephrine generated a better hemodynamics and cerebral circulation perfusion during CPR as compared to intermittent bolus doses. Thus, continuous infusion with computer micro pump was superior to intermittent bolus doses administering epinephrine during CPR.