人工心肺機(jī)ppt課件-資料下載頁(yè)
2025-01-17 15:48本頁(yè)面
【正文】 chine takes over the functions of the heart and lungs. Also known as a cardiopulmonary bypass machine, it allows the heart to can be carefully stopped and drained of blood. Surgeons can then operate in a bloodfree, quiet surgical field. The heartlung machine allows surgeons to perform plicated surgeries without the interference of a beating heart. 127 About heartlung machines The heartlung machine basically consists of a pump (to replace the heart) and a bubble oxygenator (to replace the lungs). Acting as a mechanical heart and lungs, it keeps oxygenrich blood flowing throughout the body after the patient’s heart has been carefully stopped. 128 About heartlung machines In a process called perfusion, the machine receives the patient’s blood, removes the carbon dioxide and other waste products, adds oxygen, warms (or cools) the blood and pumps it back through the body. 129 About heartlung machines Cooling the blood lowers body temperature. This helps protect the body39。s ans while the heartlung machine is in use. After the surgery is pleted, the heart is restarted, the heartlung machine is stopped and the machine is disconnected from the patient. 130 About heartlung machines The heartlung machine can perform other tasks. For example, it can directly deliver medications into the recirculated blood. It can also minimize blood loss by vacuuming up and recirculating any blood that may get into the surgical field. 131 About heartlung machines The first step in using a heartlung machine during openheart surgery is to give the patient a drug called heparin, which is a powerful anticoagulant. Heparin reduces the blood’s ability to clot, reducing the risk of clots forming in the heartlung machine and within the tubes placed in the heart. 132 About heartlung machines Once the medication has taken effect, a tube (cannula) from the heartlung machine is placed in the upperright chamber of the heart (the right atrium), which receives oxygenpoor blood from the body. 133 About heartlung machines Another cannula is placed in the aorta, a large artery that carries oxygenrich blood from the heart to the rest of the body. By setting up the machine in this way, oxygenpoor blood drains into the machine, receives fresh oxygen and is returned to the aorta to be carried to the rest of the body. 134 About heartlung machines Once the machine is functioning, the surgeon can carefully stop the heart with medications in order to perform the necessary surgery. A patient may remain on the heartlung machine for several hours, though surgeons typically try to limit the amount of time (when) patients are on bypass. 135 About heartlung machines When the surgery is plete, the surgeon will restart the heart. Once the surgical team is satisfied that the heart is beating strongly again, the tubes are removed from the right atrium and the aorta. To reverse the effects of the heparin given at the beginning of the process, the patient will be administered another medication called protamine. 136 About heartlung machines Throughout this process, the heartlung machine is operated by a perfusionist, one of several medical specialists on hand in the operating room during openheart surgery. While the heart is stopped and the machine is working, the perfusionist continually monitors blood pressure , blood oxygen levels, carbon dioxide levels, blood temperature and breathing 137 07j7 THE END
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