الفهرس 
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Abstract
Cardiopulmonary cardiopulmonary bypass (CPB) is a technique allows blood to bypass the heart and lungs, and takes over the function of the heart and lungs temporarily during surgery, to maintain the circulation of blood and the oxygen content of the body.
The typical cardiopulmonary bypass circuit includes many disposable components oxygenator, blood collection reservoir, heat exchanger, tubing, arterial filter and bubble trap, and various suction systems.
Blood is drained passively from the venous side, collected in the oxygenator where oxygen is added and carbon dioxide is removed. Oxygenated blood is then pumped to the arterial side using pumps that control rate of flow. Heat exchangers enables body cooling and rewarming in case of hypothermia is needed. Variable monitoring and safety devices can be added to the bypass machine.
Cardiopulmonary Bypass (CPB) associated pulmonary dysfunction is a common postoperative problem, it is believed to be multifactorial; due to inflammatory reactions, lung ischemia-reperfusion, microembolic and hemolytic.
CPB as a foreign body initiates whole bode inflammatory response that can have prominent effect on lungs. Neutrophils play major role in disturbing alveolar capillary membrane. Complement activation with release of oxygen free radicals acts augments the inflammatory response. Blood contact with CPB tubes although primed with anticoagulants still activates coagulation process to somehow, forming micro emboli that is scattered in the lungs. Previous mechanisms act in a synergestic way.
Pulmonary dysfunction presents clinically either in the form of a mild oxygenation defect or Acute lung injury, or even full blown respiratory distress syndrome. Lung morbidity due to CPB is not uncommon and can result in a significant mortality.
To alleviate this lung injury a number of possible interventions exist. Pump material modification may reduce the degree of systemic inflammation. The use of leukocyte filtration can attenuate the acute inflammatory response with encouraging though variable results. Aprotinin, Pentoxyfilline, Ulinastatin, Prostacyclin and other agents have shown benefits in lung function after cardiopulmonary bypass induced lung injury other factors preoperative and postoperative should be managed.
Lung ventilation and/or perfusion with different modes have shown better postoperative results in many cases. The degree of hypothermia applied during CPB can also provide better lung functions after cardiac surgery.