13. What is the effect of hypothermic injury and ischaemia following cardiopulmonary bypass?
Correct answer: This may result in pancreatitis and contribute to the occurrence of peptic ulceration and mesenteric ischaemia.
12. What is the effect on the blood as it passes through the cardiopulmonary bypass circuit?
Correct answer: Passage through the bypass circuits activates the clotting cascade and consumes platelets, thus increasing the risk of haemorrhage.
11. What is the effect of haemorrhage following cardiopulmonary bypass?
Correct answer: Haemorrhage postoperatively may result in cardiac tamponade. Passage through the bypass circuit activates the clotting cascade and consumes platelets, thus increasing the risk of haemorrhage.
10. What is the effect of emboli following cardiopulmonary bypass?
Correct answer: Air entrapped during formation of the bypass circuit or entering during bypass, or thrombus forming in the bypass circuit, may embolize into the cerebral and peripheral circulation with catastrophic results.
9. What are the three main complications of cardiopulmonary bypass?
Correct answer: (1) Emboli. (2) Haemorrhage. (3) Hypothermic injury and ischaemia.
8. How does ‘cardioplegic’ solution work?
Correct answer: This cold solution is infused via the coronary arteries. It contains potassium so produces a rapid cardiac arrest in diastole.
7. What is ‘cardioplegic’ solution used for?
Correct answer: The heart may be stopped once on cardiopulmonary bypass and can be cooled by infusion via the coronary arteries of cold ‘cardioplegic’ solution containing potassium, to produce rapid cardiac arrest in diastole.
6. What is the technique of cardiopulmonary bypass? What is the role of ‘cardioplegic’ solution?
Correct answer: After full heparinization, cannulae are inserted into the venae cavae via the right atrium to siphon off the venous return from the systemic circulation. The blood is then pumped through an oxygenator and a heat exchanger before returning…
5. What has been possible with the development of cardiopulmonary bypass?
Correct answer: It is now possible to stop the heart for prolonged periods while a machine is used to take over the pumping and oxygenation of the blood. Generally, a combination of hypothermia and cardiopulmonary bypass is used.
