A breathtaking medical science
The human heart is difficult to replace completely even with the most advanced device. Therefore, doctors try to save the patient this vital organ, placing only part of his functions on the implant. As a rule, we are talking about an artificial left ventricle.
Such an operation is performed when, for some reason, a donor heart transplant is not possible. “Cyborgization” can be either a temporary solution (for example, if the donor body is not yet available), and the only way to save the patient, to whom transplantation is not explicitly shown. So, after transplanting a living heart, suppression of the immune reaction is required, so that rejection does not arise. But with some diagnoses (in particular, oncological), immunity cannot be suppressed in any case. An artificial organ gives a person a few more years of life (sometimes more than ten).
“After such intervention, a person is restricted in movement, because the pump constantly requires recharging,” says the head of the Center for Aortic and Coronary Artery Surgery at the National Medical Research Center named after Academician E.Meshalkin, Doctor of Medical Sciences Alexander M. Chernyavsky. “For example, it will be difficult to fly away to America: modern batteries hold no more than 9 hours, and the flight lasts 12. But the train is easier: there are outlets. “
Usually, as a “mechanical heart” a vane pump is used. The wheel with blades rotates at a speed of seven to ten thousand revolutions per minute, pumping during this time to ten liters of blood.
The power comes from two batteries: each of them provides the pump for about four hours,” adds Chernyavsky, “when one is discharged, the patient puts it on a charge, and the heart at that time works from the other.” During sleep, patients connect to a normal electrical network through a special switch.Charging takes place through the cable coming out of the body: it needs to be taken care of, tied up, so that there are no infections.
In pumps of a different type, disks rotate, and not a wheel with blades. Specialists of the Meshalkin Clinic and the Institute of Theoretical and Applied Mechanics. SA Khristianovich of the Russian Academy of Sciences developed the first such domestic pump. The electric motor rotates a stack of disks separated by a gap of half a millimeter. Previously, such a system was used in space technology.
The new pump is quite small: it’s four centimeters in diameter and two centimeters high, so it’s easier and more convenient to implant it,” he notes. “At the same time, he is able to pump 7-8 liters of blood per minute. the risk of blood clots.Outside the disk wall is formed without an erythrocyte layer of plasma, therefore red blood cells do not contact the surface and due to this, damage to blood elements is prevented.
Now there is a development of an electric motor suitable for a new pump. Engineers have already managed to limit its power to a value of 5-6 watts, so that heating does not lead to blood clotting. Now you need to create a special bearing and a special coating to reduce friction.
Also, the authors are working on the technology of contactless charging of batteries using an alternating electromagnetic field. The point is that in the literal sense, the cable sticking out of the heart serves as a conductor of infections. Needless to say, how dangerous is this infection.
Researchers hope that in the next two years the stage of bench trials will successfully end, and the team will move to experiments on animals.
Recall that earlier “Vesti.Nauka” wrote about how scientists have turned the heart cells into “chameleons” and how to slow the aging of this organ.