Establishment Of A Model Of Exsanguination Cardiac Arrest In Rabbit And Its Application

Background and objective In order to simulate the pathophysiological process and its treatment of exsanguination cardiac arrest,and the application of the CPR and fluid resuscitation in this model.Our group establish a model of severe bleeding which can cause cardiac arrest so as to provide basis for basic study of multiple trauma.Methods(1)Twenty-seven New Zealand rabbits were equally and randomly divided into three groups,ie,sham group(Group A,with no bloodletting or resuscitation),uncontrolled group(Group B,with bloodletting alone),controlled groups(Groups C with bloodletting and resuscitation).Group A connect the PcLab and then without any process.An estimated 50%of total blood was withdrawn from the right jugular vein and the ri-ght femoral artery in bloodletting groups.When reach the state of cardiac arrest,Maintain it for 15 minutes.Resuscitation using lactated Ringer’S solution(LR)and autotransfusion were performed for Groups C.Arterial blood sample Was taken at each time point for blood gas analysis and coagulation test,fluid requirements.blood loss and rabbits’ survival rate at 6h were recorded.After 6h,rabbit were killed and the myocardial and kidney tissue acquired to pathological section.(2)Twelve New Zealand rabbits were equally and randomly divided into two groups,Group A(with fluid resuscitation alone),Group B,(with fluid resuscitation+CPR),after the success of the model,to resuscitate by their way.Arterial blood sample Was taken at each time point for blood gas analysis and coagulation test,fluid requirements.blood loss and rabbits’ survival rate at 6h were recorded.After 6h,rabbit were killed and the myocardial and kidney tissue were acquired to pathological section.Results(1)After the model constructing successfully,the MAP decreased to(14.5±5.3)mmHg.ln the 30min resuscitation.rabbits had reached the return of spontaneous circulation,the MAP increased to(69.75± 14.37)mmHg,HR was(185.25± 12.89)times per min;ln the blood gas analysis,the pH value、PaCO2、Hct、Na+、Cl-、Hb、actual bicarbonate、standard bicarbonate、actual base excess、standard base excess were significantly decrease and the K+、lactic acid were elevated significantly in the 5 min of resuscitation(Compared with Omin:P<0.01);The actual bicarbonate、standard bicarbonate、actual base excess、standard base excess were significantly different and only the K+ restored to the 0 min.The myocardial H.E staining show:cellular edema and necrosis is lighter,intercellular space widened slightly,the intercellular space is unclear and irregular arrangement in group C and it is not serious as group B.The changes of necrosishyaline and inflammatory cellular infiltration were all existed in the renal tubular epithelial cells,the group C is more obvious than group B in vacuolated degeneration.(2)the recovery in 5 minutes、10 minutes、15minutes and 30minutes were significantly different(P<0.01);the recovery in 60 minutes,the MAP in group A was(84.6±4.34)mmHg while group B was(87.8±5.26)mmHg(P>0.05).In the blood gas analysis,the PaCO2 in group A was(41.76±1.28)and group B was(50.72±6.03)at the moment of recovery in 5 minutes(P<0.01),while other index had no statistical difference(P>0.05).Both two groups have a rabbit failure,the successful rescue rate is 83.7%;Both two groups had two rabbit didn’t survive to 6 hours,The final survival is 60%.Conclusions(1)Through exsanguination from the right jugular vein and the right femoral artery,the exsanguination cardiac arrest model of rabbit was established to mimick the clinic situation and lay a foundation for further study of exsanguination cardiac arrest(2)There is no difference in the rescue success rate and survival rate in the observation 6 hours between the CPR+ fluid resuscitation and fluid resuscitation alone.Accroding to the reserch,the only dvantage of combining CPR is more faster to achieve the ROSC.