Domande teoriche + Risposte, Biomacchine

Reason for Different Frequency Curves Trend in Aortic Valve and Mitral Valve Prosthesis

In the abacus related to the aortic valve prostheses, we can see that for increasing values of the frequency, the lines tend to go lower, while the opposite happens for mitral valve prostheses. This behavior can be explained by considering the aortic valve first.

During the systolic phase, if the frequency increases, the systolic time doesn't change, so the pressure gradient becomes smaller (as seen in the charts) and the stroke volume decreases. On the other hand, in the diastole phase, time decreases if the frequency increases, so the mitral valve has less time to pump the same amount of blood. This means that the pressure gradient becomes bigger.

Pros and Cons of Using a Centrifugal Blood Pump (or a Roller Pump) in an ECC Circuit and Weaning Procedures

During weaning, the pump and heart work in parallel. For roller pumps, we need to...

filling the blood with oxygen – filter to remove any debris or clots – arterial line to deliver the oxygenated blood to the patient. The sequence of the different components in an ECC circuit is designed to ensure the proper functioning of the cardiopulmonary bypass system. 1) Cannula: The cannula is the entry point for blood to be diverted from the patient's body into the ECC circuit. It is usually inserted into a major blood vessel, such as the aorta or the right atrium. 2) Reservoir: The reservoir is where the priming solution is stored. It is important to fill the pump with priming solution to prevent air bubbles from entering the patient's bloodstream. 3) Pump: The pump is responsible for circulating the blood through the ECC circuit and back to the patient. It is crucial to ensure that the pump is working properly, especially for centrifugal pumps, as any air inside the pump can cause it to malfunction. 4) Heat exchanger: The heat exchanger helps regulate the temperature of the blood as it flows through the ECC circuit. This is important to maintain the patient's body temperature during the procedure. 5) Oxygenator: The oxygenator is located downstream of the heat exchanger and is responsible for adding oxygen to the blood. It ensures that the blood is properly oxygenated before being delivered back to the patient. 6) Filter: The filter is used to remove any debris or clots from the blood before it is returned to the patient. This helps prevent any potential complications or blockages. 7) Arterial line: The arterial line is the final component in the ECC circuit and is used to deliver the oxygenated blood back to the patient's body. The sequence of these components is carefully planned to ensure the proper flow and oxygenation of the blood, as well as to minimize the risk of complications during the procedure.

problems of partial pressure – filter to give back clean blood - cannula

7) Discuss the differences of either placing the heat exchanger upstream or downstream the oxygenator in the ECC circuit and justify the choice to place it upstream.

Related to the partial pressure

8) Describe how to perform the in-vitro test for a heart valve prosthesis. What is the Standard to follow for these tests? Describe the set-up, the testing protocol and what you have to measure to calculate the Effect Orifice Area.

The Standards to follow in order to test a heart valve prosthesis are decided by ISO or FDA based on the Country and they usually give both the way of testing and the minimal requirements. There are many tests, for example a valve can be evaluated