I would say “The biomedical engineer is the writer of the soul “.
Human heart is an astound organ that acts as a DUAL PUMP.
WORKING OF HEART DURING AN OPEN HEART SURGERY
STRUCTURE OF HUMAN HEART:
The human heart consists of 4 chambers that include the 2atrium (plural: atria) and 2 ventricles. The right atrium and left atrium or the upper chambers serve as inputs to the pump while both the ventricles or the lower chambers serve as output for the pump.
The vessels of the human heart include arteries and veins that carry blood away from and to the heart respectively.
The pulmonary artery is a special kind of artery that carries deoxygenated blood to the lungs from the heart whereas the Pulmonary vein is a special kind of vein that carries oxygenated blood from the lungs to the heart.
Blood from the head, arms, and upper portion of the body returns to the heart through the Superior Vena Cava in turn blood from the lower portion of the body returns to the heart through the Inferior Vena Cava.
WORKING OF HUMAN HEART AND LUNGS :
The deoxygenated blood from various parts of the body is carried by the superior and inferior vena cava to the right atrium. From the right atrium, it enters the right ventricle through Tricuspid Valve.
From the right ventricle, the blood(deoxygenated) reaches the lungs through the Pulmonary Artery where it gets oxidized. The oxidized blood is traversed back to the left atrium of the heart by the Pulmonary Vein from where it enters the left ventricle through the Mitral Valve.
Then the oxidized blood from the left ventricle reaches the Aorta from where it is transported to all the body parts and again the deoxygenated blood is collected and is brought back to the right atrium where the cycle is repeated again and again thus giving rise to the heartbeat “lub dub “.
This is during a normal condition. But can you think of how a heart works when there is open-heart surgery?
Keeping a heart beating condition and operating on it is a very challenging situation faced by the doctor. CARDIOPULMONARY BYPASS MACHINE (heart-lung machine) tackles this.
CARDIOPULMONARY BYPASS MACHINE:
A cardiopulmonary bypass machine is mainly used in open-heart surgery during which the blood has to be oxidized, filtered, and pumped by an extracorporeal(i.e., outside the body) pump called the heart-lung machine.
This heart-lung machine can take up the function of both the heart and lung as it pumps as well the oxidizes the blood and hence is the name.
Generally, inspiration and expiration are mainly due to the difference between intrapulmonary pressure(i.e., pressure within the lungs) and atmospheric pressure.
If there is a negative intrapulmonary pressure, inspiration takes place while on the other hand if there is a negative atmospheric pressure expiration takes place. But in the case of open-heart surgery, both pressures are equal due to which there will be no pressure gradient.
The mechanism of the heart-lung machine is that the deoxygenated blood that reaches the right atrium is then taken to a specialized reservoir called OXYGENATOR through a flexible tubing, where oxygen bubbles up and enters the blood changing its color from dark red (oxygen-poor) to bright red (oxygen-rich).
This oxidized blood is then allowed to pass through a nylon mesh filter that filters the oxygen bubbles if any is present in the blood. From this, the oxidized blood is taken back to the AORTA ( the largest artery attached to the left ventricle) through a specialized plastic tubing called CANNULA from where it is pumped throughout the body.
