Acute Severe Hemorrhagic Shock Model Of Rats

Background:Acute severe hemorrhagic shock that was caused by artery rupture during in the process of operation,is a common expectations of the operating room,which was a serious threat to patient. The principle of treatment for the severe uncontrolled hemorrhagic shock are to stop bleeding as soon as possible, maintain airway, increase the arterial blood of critical organs flow,use of vasoactive drugs reasonablely, correct acidosis and prevent cardiopulmonary arrest.If hemostasis failed in short time, it is particularly important that fluid resuscitation and using of vasoactive drugs sensibly,which can maintain the critical organ and prevent cardiopulmonary arrest.Therefore, fluid resuscitation and vasoactive active drugs has been a heated research issue over the appropriate treatments for patients who suffer massive bleeding after severe injury in recent years. Clinical severe trauma resulting in artery rupture, blood loss fast, quickly enters the shock in the short term, and shock degree is very heavy, bleeding can’t be controlled within a certain time, liquid recovery unable to maintain blood pressure. The vasoactive active drugs can constricts blood vessels,increase cardiac output and maintain the coronary arterial blood flow. An updated European guideline pointed out that:in a positive capacity recovery situation, for the blood volume shock patient of persistent low blood pressure low, doctors can choose to use vascular active drug epinephrine (E).However, compared with norepinephrine,the same dose epinephrine maintain blood pressure effectivelier in the condition of serious uncontrolled hemorrhagic shock. In the traditional study of the uncontrolled hemorrhagic shock, more commonly used animal models include the following three types:fixed blood pressure uncontrolled hemorrhagic shock model, fixed blood loss model of uncontrolled hemorrhagic shock, non-control uncontrolled hemorrhagic shock model. Fixed bleeding is easy to control, but most do not tally with the clinical. The severe hemorrhagic shock model at present is unable to clear the timing of using large doses of epinephrine.Norepinephrine is used to treat refractory shock, but when shock degree is very heavy, norepinephrine could not make blood pressure to rise, according to this, this article try to find a bleed the finish.Methods:(1)Building the acute severe hemorrhagic shock model of rats: bleeding is made into two stages. In the first stage, the anesthetized rats was bleeded 50% of the whole blood within 20min. In the second stage, slow down to half the original speed and continue to bleed. The rats received A,B,C,D four different bolus dose infusion of norepinepHrine(A=10ug/kg, B=50ug/kg, C=100ug/kg,D=500ug/kg). When the rats injected A dose norepinepHrine and the blood pressure could not rise anymore,it received B dose infusion of norepinepHrine. When the rats injected D dose norepinepHrine and the blood pressure did not increase any longer when it was set as the end of bloodletting. Use MAP cardiac function monitor to continuously monitor the MAP. Collect and analyze the arterial blood before bleeding, the first stage and the second stage arterial blood with blood gas analyzer and record the final blood loss.(2) Evaluation methods of effectiveness:Prepare shock model according to the above method. Animals were randomly divided into four groups:0.9% normal saline group(NS group,n=10), high-dose dopamine group(DA group,n=10), high-dose norepinepHrine group(NE group,n=10), high-dose epinephrine group(E group,n=10). DA group,NE group and E group received injection(500μg/kg). Observe the changes in MAP 5 minute after injection of drugs and write down the values of MAP and HR of 0.5min, lmin,1.5min,2min, 2.5min,3min,3.5min,4min,4.5min and 5min.Results:1. A total of 40 model is established,which succeeded in 28 cases(Model group,n=28),12 cases failed(Failed group,n=12).When the blood loss was greater or equal to 25%,the difference between the two groups in arterial blood pressure and heart rate had significant statistically difference (P< 0.05).When the rats of failed group dead, the final blood loss was (7.01± 1.23) ml and the percentage of blood loss was (47.11±6.34)%.When the model was builded successfully, the final blood loss of rats was (10.90 ± 1.11) ml and the percentage of blood loss was (73.87 ± 7.22)%. The difference between the two groups had significant statistically difference (P <0.05).2.The standard of the acute severe hemorrhagic shock model of rats, ① The percentage of blood loss was (73.87±7.22)%,the MAP WAS (30.73± 3.41) mmHg and the heart rate was (179.3±13.45)/min.② Arterial blood gas analysis showed HCT<10%PCV, Hb<3g/dl. ③ PH was (7.17±0.25) and BE was-(14.67±2.50)3.In the condition of acute severe uncontrolled hemorrhagic shock,compared with dopamine group and norepinephrine group,mean ± sem arterial blood pressure and heart rate of epinephrine group was significantly (P <0.05) higher.Conclustions:1. We established a stable ASHS rat model which Similarity and repeatability.The model can be used to study the effectiveness of large dose of adrenaline.2.EpinepHrine, compared with nepinepHrine, maintain blood pressure effectively and win golden time for the further treatment in a rat model of uncontrolled hemorrhagic shock after main artery injury when surgical intervention and fluid replacement was delayed.