Establishment Of Closed And Minimum Priming Volume Rat Model Of Deep Hypothermic Circulatory Arrest And Moderate Hypothermic Circulatory Arrest

Aortic dissection and aneurysm vascular disease is a major cardiovascular diseases endangering people's health,especially when the lesion involving the aortic arch department,due to the surgery often need hypothermic and keep circulatory arrest,the operative mortality and postoperative complications of visceral injury incidence is high,especially the brain and spinal cord complications of nerve injury,cause of postoperative patients with disability,which seriously influence the curative effect of aortic surgery.Therefore,it is an urgent problem in the applied basic research field of aortic disease to establish a stable experimental model of hypothermia circulatory arrest,to study the effects of HCA on the metabolism of the body and the damage to the body tissues and organs,and to further study the mechanism of relevant pathological changes.Objective: This paper applied patent pipeline with independent intellectual property rights,established closed and minimum priming volume rat model of deep hypothermic circulatory arrest and moderate hypothermic circulatory arrest.Methods: A total of 20 SD rats weighing 380-450 g were randomly divided into 4 groups.Group A(n=5):CPB only;Group B(n=5): MHCA for 30 minutes after the temperature drops to 24?;Group C(n=5): DHCA at 18? for 30 minutes;Group D(n=5): DHCA at 18? for 60 minutes.After anesthesia,the left superficial femoral artery,caudal artery and right jugular vein were separated.After the puncture was completed,the rats were placed on the extracorporeal circulation table and the extracorporeal circulation was started.The extracorporeal circulation was performed using the patented pipeline with independent intellectual property rights.The body temperature of group A was rewarmed immediately after the body temperature dropped to 24?.The body temperature of group B will reach 24? and then arrest,and rewarm after 30 minutes.After the body temperature recovered and the vital signs were stabilized,the cannula was removed,and recover on the variable temperature blanket until anesthesia fail.After 24 hours,the activity status of the rats was observed,neurobehavioral score was obtained,the rats were sacrificed by excessive anesthesia,blood gas was extracted from the abdominal aorta and samples were collected,and follow-up pathological sections and molecular experiments were conducted on the heart,lung,kidney,brain,intestine and other important organs.And the experimental results were compared with the data of open conventional priming volume group rats published by our team.Results: 24 hours after surgery,1 rat died in group B,and all the other rats survived and could move freely.During the operation,the circulation of the rats in each group was stable,the average blood pressure was maintained above 60 mm Hg,the hematopoietic volume was about 30%,and the acid and base balance in the internal environment were maintained.The highest lactic acid during the period was 10.07±1.91mmol/L in group D,9.1±1.82mmol/L in group B,5.48±0.65mmol/L in group C,and 2.64±0.83mmol/L in group A.The highest levels of blood glucose were 23.93±1.89mmol/L in group D,20.76±1.68 mmol/L in group B,16.70±2.03 mmol/L in group C,and 13.06±2.40 mmol/L in group A.After the operation,the lactic acid and blood glucose in each group reached the basic value 24 hours after the operation,without the disturbance of acid-base balance,and the blood oxygen partial pressure and carbon dioxide partial pressure were at normal values.The neurobehavioral score of group A and group C was 0,and the Berderson score of group B was 0.25±0.5.Longa score of 1.2±2.17;Berderson score of group D was 0.8±1.30;Longa score 0.6±0.89.Conclusion: The self-developed closed minimum priming volume cardiopulmonary bypass system is easy to operate and manage,having high survival rate and good repeatability.The hematocrit of the rat can be maintained at about 30% during the operation,and it can withstand DHCA for 60 min and the MHCA for 30 min,which is a good experimental platform for the scientific research of extracorporeal circulation and hypothermic circulatory arrest.