Comparison of Different Types of Blood Pumps

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Comparison of different types of blood pumps

Nowadays, there are two main types of blood pumps: kinetic pumps and positive displacement pumps. Kinetic pumps:
Centrifugal pump is one of the most familiar kinetic pumps. A centrifugal pump converts the input power to kinetic energy in the liquid by accelerating the liquid by a revolving device - an impeller. The most common type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radically outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump. The energy created by the pump is kinetic energy according the Bernoulli Equation. The energy transferred to the liquid corresponds to the velocity at the edge or vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is, the higher will the velocity of the liquid energy transferred to the liquid be. This is described by the Affinity Laws. Characteristics:

* Designed with impellers arranged with vanes or cones
* Centrifugal pumps are magnetically driven and produce a pressure differential as they rotate * It is the pressure differential between the inlet and outlet that causes blood to be propelled Advantages and disadvantages:

Advantages:
* Reduced hemolysis
* No cavitation
* No dangerous inflow/outflow pressures
* Air gets trapped in pump
* No need to calibrate
Disadvantages:
* Causes over-heating
* Over heating promotes clotting
* Difficult to de-air
* If power goes out, arterial line acts like a venous line

Positive displacement pumps:
Positive Displacement Pumps, unlike centrifugal pumps, will produce the same flow at a given speed (RPM) no matter the discharge pressure. This type of pump moves blood forward by displacing the liquid progressively, from the suction, to the discharge...
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