Heart Lung Machine Block Diagram

The main components of a heart-lung machine and their functions are briefly described below.

1. Roller Pump:

The pump comfort frequently consists of numerous revolving motor pumps that peristaltically ‘massage’ tubing. Pumping action occurs because the rollers on the rotating arm comprises the tubings carrying the blood and forces the blood ahead of the compressed section. This action is called peristaltic action and this leads to a pulsatile flow of blood through the tubings. The heart-lung machine uses five pump heads normally.

In some cases we use centrifugal pumps for the safeguarding and control of blood flow during the surgical procedure. By changing the RPM of pump head, blood flow is maintained. This kind of pumping action is measured to be better to the action of roller pumps because it produces less damage to the blood.

2. Oxygenator: 

The oxygenator is planned to move oxygen to the infused blood and take away carbon dioxide from venous blood. So simply the oxygenator assembly allows to oxygenate the blood. Bubble oxygenators, membrane oxygenators and heparin coated blood oxygenators are the different types of oxygenators. Of them, heparin coated blood oxygenators are the commonly used one as they prevent blood coating.

3. Heat Exchanger:

Heat exchangers permit body and organ temperatures to be attuned. The uncomplicated heat exchange design is a container of water. As the blood transfers through the tubing positioned in the bath, the blood temperature will alter. A more complex system separated the blood and water interface with a metallic barrier. As the water temperature is changed, the blood temperature also changes, which in turn changes the tissue temperature. Once the tissue temperature reaches the desired level, the water temperature is maintained.

Heat exchangers can be of two types namely plate type and coil type. In plate type of heat exchangers, two sheets of metals are used and they are coated with a non – thrombogenic substance. This configuration offers good efficient transfer of heat. Coil configuration consists of a hollow coil through which water circulates. The disadvantage of this type is it is a non disposable unit and is very difficult to clean.

4. Temperature Controller:

During the time the patient uses a heart-lung machine, body temperature is to be maintained at a normal range. This unit allows the pump operator to keep the blood at a proper temperature.

5. Blood and Oxygen Dispersion Plates:

In a heart – lung machine, the gas bubbles are dispersed into the venous blood in the bubble column and acts as vehicles for both oxygen and carbon dioxide. Here oxygen diffuses from the bubble into the blood film surrounding the bubble. Various types of dispersion plates are used.

6. Reservoir:

A reservoir gather blood drained from the venous flow. Reservoir arranges include open or closed systems. The open system displays demarcations corresponding to blood volume in the container. The design is open to environment permitting blood to cross with environmental gases. The closed system contains a bag and it eliminates the air-blood interface. Volume is measured by weight or change in radius of the container.

7. Nylon Mesh Filters:

The nylon mesh filters used in heart-lung machines are attuned with a broad choice of solvents. They are particularly used for gathering of algae and cells, atom analysis, big particulate filtration, prefiltration of solvents and so on.

8. Cannulae: 

Numerous cannulae are sewn into the suffering patient’s body in a diversity of position depending on the kind of surgery. A venous cannula takes away the oxygen destitute blood from the patient’s body and an arterial cannula is sewn into the suffering patient’s body to impart oxygen rich blood. The cannula utilized to return oxygenated blood is frequently inserted in the rising aorta.

1 comment:

  1. I would love to use this for my research paper if possible.