Acute Cardiac Failure in Rabbits PDF

Acute Cardiac Failure in Rabbits  Purpose and Principle Purpose: To learn the method of replication of experimental acute right heart failure and to understand the manifestations and mechanisms of cardiac failure. Acute heart failure characterized by the rapid onset an...

Acute Cardiac Failure in Rabbits  Purpose and Principle Purpose: To learn the method of replication of experimental acute right heart failure and to understand the manifestations and mechanisms of cardiac failure. Acute heart failure characterized by the rapid onset and sharp decrease of cardiac output in a short period of time.  Causes of cardiac insufficiency (I) Primary dysfunction of myocardial systole and diastole Myocarditis Myocardiopathy Myocardial destruction Myocardial necrosis, fibrosis Myocardial Myocardial ischemia from metabolism disorder Coronary artery disease Vitamin B1 deficiency  (II) Cardiac overload Mitral or aortic insufficiency volume Chronic anemia overload hyperthyroidism Pressure Systemic hypertension overload Pulmonary hypertension (III) Restricted cardiac filling  Cardiac Dysfunction Blood-supply in tissues and organs Cardiac extracardiac compensation compensation Blood-supply recover in tissues and organs I. Cardiac Compensation Increased heart rate Positive inotropic actions of catecholamine Cardiac ontogenic dilation Myocardial hypertrophy II. Extracardiac compensation increased blood volume redistributed blood flow erythrocytosis increased tissue capability to utilize oxygen  In this experiment, to make acute heart failure by increasing pressure overload and volume overload in right heart in a very short time. Inject liquid paraffin to pressure overload make thromboembolism Inject normal saline to heart from ductus venosus massively and rapidly volume overload  Methods and Procedures 1 Rabbit weight. 2 anesthesia： Inject 30% urethane from marginal ear vein slowly, 3.3ml/kg, then fix it on operating table. 3 Operation: Shear the fur on neck, cut a 5~7cm incision On the skin along the midline of cervical part. 4.Separate the left common carotid artery and insert a arterial cannula into it then connect the cannula to transducer ,in order to measure blood pressure. 5. Separate the right vena jugularis externa and insert a venosus cannula for 5~6cm to right atrium ,connect with the thansducer to measure CVP. 6.Inject heparin solution 2ml/kg into vein in the edge of an ear to prevent from cruor, then inject the solution full into the transducer that connects to a plastic artery cannula. 7. Open the computer , Observe blood pressure. 8. Inject liquid paraffin 0.5~1ml into vein in the edge of an ear to make thromboembolism , and observe the change of blood pressure. 9. Inject normal saline to heart massively and rapidly from ductus venosus,and observe the change of CVP. 10. After the death, Open the chest and abdominal cavity ,observe heart ,liver, ascites.  Result 1 Blood pressure 2 CVP 3 Heart 4 Liver 5 Ascites  Questions 1. How many kinds of compensations in this rabbit? Increased heart rate Positive inotropic actions of catecholamine Cardiac ontogenic dilation Myocardial hypertrophy 2.What is the cause of heart failure in this rabbit? pressure overload volume overload Discuss the mechanisms of cardiac failure in this experiment.