外科学教学课件：Cardiopulmonary Bypass

1、Cardiopulmonary Bypass What is Cardiopulmonary Bypass(Extracorporeal Circulation)?To perform heart surgery, the cardiothoracic surgeon requires a bloodless, motionless field in which to work. To achieve this, the movement of the heart and lungs must be stopped. For this to occur, there needs to be a

2、 means for blood to circulate throughout the body, delivering the nutrients and oxygen necessary for life, while the heart and lungs are not functioning. This is made possible through a process known as cardiopulmonary bypass (CPB). In this way, cardiopulmonary bypass permits the patients blood to b

3、ypass the heart and lungs, achieving the desired bloodless, motionless operative field and still supplying all the other organs of the body with a constant supply of oxygen and nutrient-rich blood. Summary for CPB:1.purpose: A. to provide a bloodless, motionless operative field B. rest of body perfu

4、sed while heart arrest2.methods: A. draw out venous blood B. oxygenated by artificial lung C. oxygen-rich blood pumped back by artificial heart 3.Definition: CPB is a basic and necessary technique for intracardiac surgery.The heart-lung machine replaces the function of the heart and lungs to provide

5、 a bloodless, motionless surgical field for the surgeon. The oxygenator ventilates the patients blood to control the level of oxygen and carbon dioxide. The blood pump drives the patients blood back into the arterial system to provide nutrient blood flow to all the patients vital organs and tissues

6、during heart surgery.Basic equipment 1.artificial heart (blood pump)2.artificial lung (oxygenator)3.heat exchanger4.filter5.tubes and cannulae Artificial Heart- Blood pump (perfusion machine)Roller pump: pulsatile or nonpulsatileCentrifugal pump:Artificial Lung -Oxygenator (Bubble,Membrane)Heat exch

7、anger:Hypothermia (mild32-28,deep27-20 ,profound20-15) TubesCannulaeTypical cardiopulmonary bypass process for open heart surgery1) chest opened by sternotomy, heart and great vessels exposed;2) anticoagulation with heparin;3) aorta and SVC.IVC cannulations;4) connect patient to cardiopulmonary bypa

8、ss machinethe bypass system established;5 ) start the bypass machine and topical hypothermia( decrease blood temperature)6 ) aortic cross-clamp placed,cardioplegia injected,the heart arrested7 ) open heart surgery.8 ) re-warming,deair, release aortic clamp,heart resuscitation9 ) gradually wean off b

9、ypass(off pump)10) administration of protamineagainst heparin:-restore cloting functionOpen heart surgery under CPB is going Median sternotomyIncision of sternal periosteum Sternum divided by sawPericardium openedheart and great vessels exposedaorta and SVC.IVC cannulation CPB under goingClinical ap

10、plication:Heart surgery (Congenital heart diseases ,Cardiac valve diseases ,Coronary artery diseases ,Great vessel diseases,etc.)ECMO(extracorporeal membrane oxygenation,life support technique)Pathophysiological changes after CPB1,metabolic changes: metabolic acidosis, respiratory alkalosis2,electrolytes turbulence: hypokalemia3,blood damage: blood cell damages, cloting facto