Surgery – Cardiac augmentation
Reexamination Certificate
2001-12-07
2004-11-16
Manuel, George (Department: 3762)
Surgery
Cardiac augmentation
Reexamination Certificate
active
06817971
ABSTRACT:
CLAIMING FOREIGN PRIORITY
The applicant claims and requests a foreign priority, through the Paris Convention for the Protection of Industry Property, based on a utility model application filed in the Republic of Korea (South Korea) with the filing date of Sep. 25, 2001, with the utility model application number 10-2000-0032507, by the applicant. (See the attached declaration)
BACKGROUND OF THE INVENTION
The invention relates to an artificial heart for a patient requiring a cardiopulmonary life support in form of either artificial heart implantation or extracorporeal heart assistance. More specifically, the present invention relates to a cardiopulmonary life support system that substantially prevents blood clotting (thrombus) and dissolution or destruction of red blood cells (hemolysis) from occurring in blood vessels of a heart patient who receives its assistance.
FIG. 1
is a schematic view showing a heart
2
, lungs
4
and a blood circulation in a mammal or a human, wherein arrows indicate direction of the blood circulation. As shown therein, the heart
2
includes two atriums above and two ventricles below. A main vein
6
is connected to the right atrium and the right ventricle is linked to a pulmonary artery
8
. The lungs are connected to the left atrium and the left ventricle is linked to an aorta
10
. Regular pumping of the left ventricle pushes out blood therein into the aorta
10
to deliver nutrition and oxygen to each capillary vessel in the body. Meanwhile, the blood with less oxygen is in turn collected in the main vein that links to the right atrium to complete a blood circulation known as a systematic circulation. The oxygen-depleted blood collected in the right atrium is released down to the right ventricle and sent to each lung through the pulmonary artery for blood oxygenation. The blood oxygenated in the lungs is released through the left atrium down to the left ventricle. Through the blood circulation for blood oxygenation also known as a pulmonary circulation, the oxygen-depleted blood is converted to an oxygen-rich blood and collected back in the left ventricle. The oxygen-rich blood collected in the left ventricle repeats the systematic circulation in accordance with the regular pumping which generates rhythmic pulses. A valve in each atrium and ventricle serves to prevent a reverse stream.
Each rhythmic pulse in the atriums and ventricles differs depending on age, sex and physical condition. However, the heart pulse frequency for an individual is regular in a stabilized condition. A standard per-minute heart pulse frequency is known to range about 100 to 140 for infants, 80 to 90 for elementary school kids, 60 to 80 for young and middle aged adults, and 60 to 70 for senior people. Male tends to be less in pulse frequency than female. In general, the smaller the body, the more frequent becomes the heart pulsation for animals. If the body-surface area is larger than the body volume, heat emission becomes further invigorated and thus blood circulation should be faster to complement the loss resulting from the heat emission. For example, the per-minute pulse frequency ranges about 30 to 40 for elephants, 90 to 90 for dogs, 140 to 160 for rabbits, and 200 to 300 for rats. The pulse frequency in an artificial heart can be adjusted by controlling the rotation of a motor that drives the artificial heart.
The heart along with lungs is the most crucial organ that allows a living body to maintain its life. However, the heart should remain motionless and emptied in order to conduct a precise surgical heart operation. Therefore, considering the vitality of the heart without which the life does not last more than five minutes, an artificial heart or cardiopulmonary assistance device should be inevitably utilized in such life threatening urgent circumstances as a heart attack, a sepsis related shock, or a myocardium infraction.
Many studies on artificial hearts have been focused on blood pumping which most affects functioning of an artificial heart in a body. The leading conventional arts regarding artificial hearts will be now briefly described focusing each function of blood pumping.
FIG. 2
is a view showing a conventional cardiopulmonary device using a rotary pump. As shown therein the rotary pumping device includes a blood storage, a rotary type pump
12
, an oxygenator
13
, and a flexible tube
14
. The blood storage
11
stores therein a blood from a main vein of a patient. The rotary blood pump
12
serves to transfer the blood from the storage
11
to the oxygenator
13
. The flexible tube
14
links the blood storage
12
and the oxygenator
13
. The flexible blood tube
14
is arc-bent by 90 degrees around the rotary blood pump
12
. A rotation shaft
15
is radially formed from the arc-bent portion of the tube
14
through the center of the rotary pump
12
. A rotation arm
16
is engaged to the rotation shaft
15
and two rotary rollers
17
are rotatably provided to rotate in accordance with the rotation shaft
15
. The rotation of the shaft
15
allows the pump
12
to serve to make a sequential squeezing rotation along the arc-bent portion of the tube
14
. However, the squeezing rotation of the pump
12
fails to generate a stable, pulsatile blood pumping. Further, the excessive pressure for the squeezing rotation tends to easily lead to thrombosis and hemolysis in the oxygenator
13
. Also, the rotary pump
12
is only usable for about 6 to 8 hours which substantially limits its application to a time taking surgical heart operation.
FIG. 3
shows a schematic cross-sectional view of a conventional centrifugal blood pump
21
. The centrifugal blood pump
21
includes an input port (not shown) to receive blood from a flexible tube (not shown) connected to a right atrium, an output port
22
to release the blood from the blood pump
21
, and an impeller
23
having blades. The rotation speed of the impeller
23
can be adjusted depending on a patient. However, since the blood in the centrifugal blood pump
21
becomes in contact with either the inner surface of the blood bump
21
or mechanical surfaces of the impeller
23
, there may easily occur blood clotting or blood dissolution.
In particular, the damage incurrence on red blood cells or blood platelets due to the blood clotting and dissolution is determined by stress resulting from the blood flow in the pump
21
and by how long the blood has stayed in the pump
21
. Also, the stress due to the blood flow is determined by the rotation speed of the impeller
23
and by the asperity of the mechanical surfaces, thereby increasing possibility of blood damage. The time period in which the blood stays in the centrifugal blood pump
21
is a major factor to consider in the pump design. A shear stress sufficient to affect the blood staying in the pump may lead to thrombosis resulting from congelation, embolism or fibrin accumulation on the inner surface of the pump. There may also occur blood dissolution or red cell destruction due to a flow separation, a cavitation, or a solution swirl which may be caused by the rotation of the impeller
22
. Therefore, the centrifugal blood pump
21
can be utilized for a limited time period like the rotary blood pump.
FIG. 4
shows a conventional pulsatile blood pump
31
. As shown therein, the pulsatile pump
31
includes a bag tube
32
, a pressure plate
33
, a plate support
34
, a rotation body
35
, and a drive motor
36
. The bag tube
32
is provided with a valve (not shown) at each end thereof. The pressure plate
33
pressurizes the tube
32
for blood transfer. The plate support
34
supports and vertically shuttles the pressure plate
33
. The rotation body
35
is threaded to allow the plate support
34
to make a vertical reciprocal movement.
When the pressure plate
33
the plate support
34
are lowered according to the rotation body
35
driven by the motor
36
, the blood is discharged from the tube
32
, and when raised the blood is supplied into the tube
32
, thereby enabling the pulsatile blood pumping. However, the pulsatile blood pump
31
ma
Baek Kwang J.
Hwang Chang M.
Lee Hyuk S.
Lee Jung C.
Lee Whang J.
Manuel George
Newheartbio Co., LTD
Park John K.
Park & Sutton LLP
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