WO2009110652A1

WO2009110652A1 - A pulsatile cardiopulmonary auxiliary device

Info

Publication number: WO2009110652A1
Application number: PCT/KR2008/001820
Authority: WO
Inventors: Gi Beum Kim; Hyung Sub Kang; Chul Un Hong; Min Ho Kim; Sung Jong Kim; Jin Shang Kim; Mun Yong Lee; Seol Hee Jeon; Sung Zoo Kim
Original assignee: Industrial Cooperation Foundation Chonbuk National University
Priority date: 2008-03-07
Filing date: 2008-04-01
Publication date: 2009-09-11
Also published as: KR20090095975A; KR100985985B1

Abstract

A pulsatile cardiopulmonary auxiliary device is provided. The pulsatile cardiopulmonary auxiliary device externally circulates blood from a human heart, and supplies oxygen to the circulating blood, and includes an oxygenator unit to not only circulate the blood, but also oxygenate the blood, in which the oxygenator unit includes a main body, a plurality of hollow fibers arranged inside the main body, and an expansion member to periodically contract/expand the main body, thereby pumping the blood from the human heart to circulate. If the blood is introduced into the main body, the blood is in contact with an external surface of the hollow fibers and supplied with the oxygen passing through an interior of the hollow fibers.

Description

Description A PULSATILE CARDIOPULMONARY AUXILIARY DEVICE

Technical Field

[1] The present invention relates to a pulsatile cardiopulmonary auxiliary device, and more particularly, to a pulsatile cardiopulmonary auxiliary device having an artificial heart function unit to externally circulate patient's blood flow, and an artificial lung function unit to oxygenate the circulated blood flow. Background Art

[2] Generally, a cardiopulmonary auxiliary device is a mechanical pump which maintains circulation of a patient's blood flow during cardiac surgery. The cardiopulmonary auxiliary device externally bypasses the blood flow from the heart, and circulates the oxygenated blood back to the patient's body. The cardiopulmonary auxiliary device essentially consists of an artificial lung unit (oxygenator) and an artificial heart unit (pump). Since 1868, that is, for almost one century, the scientists strived to develop a machine to oxygenate the blood which is deprived of oxygen while moving through the tissue, and to remove excessive carbon dioxide which is accumulated during delivery. Many researchers also tried to develop a pump to temporarily replace the heart.

[3] Referring to FIG. 1, a conventional cardiopulmonary auxliary device basically includes a pump 1, a membrane oxygenator 2, a heat exchanger 3, and an oxygen storage 4.

[4] By the roller-type pump 1 of the cardiopulmonary auxiliary device, the blood is drawn outside the patient's body. The blood is charged with the oxygen of the oxygen storage 4 while passing through the membrane oxygenator 2. The oxygenated blood is circulated back to the heart via the heat exchanger 3, and this is how the cardiopulmonary auxiliary device operates.

[5] As explained above, the pump 1 of a conventional cardiopulmonary auxiliary device is a roller type, in which the blood is circulated by the force exerted from back to front as a roller Ia presses a flexible tube 6 containing the blood. However, it is possible that the tube 6 is damaged while the roller Ia presses the tube 6 from back to front, and if the tube 6 is folded, the blood in the tube 6 cannot move further, and thus the blood circulation is obstructed.

[6] The abovementioned roller type pump has additional shortcoming. That is, since the roller Ia presses the tube 6 from back to front, the blood within the tube 6 can be damaged.

[7] Furthermore, since the pump to circulate the blood and the oxygenator 2 to oxygenate the blood are provided separately from each other, these units can be in a disorderly condition while the surgery is conducted. Disclosure of Invention

Technical Problem

[8] The present invention has been made to overcome the abovementioned problems occurring in the prior art, and accordingly, it is an object of the present invention to provide a pulsatile cardiopulmonary auxiliary device to circulate the blood smoothly.

[9] It is another object of the present invention to provide a pulsatile cardiopulmonary auxiliary device having less damages in the tube where the blood flows and so the tube has a longer lifespan. Technical Solution

[10] In order to accomplish these and other objects of the present invention, there is provided a pulsatile cardiopulmonary auxiliary device for externally circulating a blood from a human heart, and supplying an oxygen to the circulating blood, the pulsatile cardiopulmonary auxiliary device including an oxygenator unit to not only circulate the blood, but also oxygenate the blood. The oxygenator unit may include a main body, a plurality of hollow fibers arranged inside the main body, and an expansion member to periodically contract/expand the main body, thereby pumping the blood from the human heart to circulate. If the blood is introduced into the main body, the blood is in contact with an external surface of the hollow fibers and supplied with the oxygen passing through an interior of the hollow fibers.

[11] Preferably, the pulsatile cardiopulmonary auxiliary device may further include an oxygen storage in fluid communication with the hollow fibers to supply the oxygen to the blood, and a pneumatic pump to inject the air to the expansion member periodically.

[12] The main body may include a cylindrical inner housing made from a flexible urethane, and an outer housing arranged a predetermined distance away from the inner housing, and having the expansion member arranged therein, the outer housing supporting the expansion member to contract/expand the inner housing periodically according to inflation and deflation of the expansion member.

[13] A flexible inflow pipe may be formed on a lower outer circumference of the inner housing to receive a flow delivered from the human heart, and a flexible discharge pipe may be formed on an upper circumference of the inner housing to discharge the received blood, wherein the inflow pipe and the discharge pipe are formed on the inner housing in a tangential direction.

[14] The inflow pipe and the discharge pipe may be provided with a check valve to control a blood flow, and the check valve may include a first check valve formed on the inflow pipe to permit the blood flow only in a direction in which the blood is introduced into the inner housing, and a second check valve formed on the discharge pipe to permit the blood flow only in a direction in which the blood is discharged out of the inner housing.

Advantageous Effects

[15] Compared to a conventional cardiopulmonary auxiliary device which employs a roller type pump, the present invention according to an embodiment of the present invention employs an expansion member which causes the inner housing to contract and expand periodically, to provide blood pumping operation, and thus is capable of providing smooth blood circulation.

[16] Additionally, since pumping is carried out without a contact with the blood tubes, the blood tubes are not damaged and thus can have a longer lifespan.

[17] [Brief explanation of the drawings]

[18] FIG. 1 is a view illustrating a conventional cardiopulmonary auxiliary device;

[19] FIG. 2 is a view illustrating an oxygenator unit in which an expansion member is not in an expanded state;

[20] FIG. 3 is a view illustrating an oxygenator unit in which an expansion member is in an expanded state; and

[21] FIG. 4 is a schematic block diagram of a pulsatile cardiopulmonary auxiliary device according to an exemplary embodiment of the present invention. Best Mode for Carrying out the Invention

[22] A pulsatile cardiopulmonary auxiliary device according to an exemplary embodiment of the present invention will be explained below with respect to the accompanying drawings.

[23] Referring to FIGS. 2 to 4, the pulsatile cardiopulmonary auxiliary device 10 according to an exemplary embodiment of the present invention operates to oxygenate the blood which is externally drawn from a patient's body and to circulate the oxygenated blood back to the patient's body. The pulsatile cardiopulmonary auxiliary device 10 includes an oxygenator unit 100, a blood tube 200, a heat exchanger 300, and an oxygen storage 400. Herein, the oxygenator unit 100 having a pumping function is the main feature of the present invention, and the components such as the blood tube 200, the heat exchanger 300 and the oxygen storage 400 are the general conventional devices. Accordingly, a detailed explanation of the blood tube 200, the heat exchanger 300, and the oxygen storage 400 will be omitted wherever possible in the description below.

[24] The oxygenator unit 100 includes an integrated function unit having a pump unit to circulate the blood flow so that the blood is drawn out of the patient's heart and circulated back, and a unit to supply oxygent to the blood.

[25] Referring to FIGS. 2 to 4, the oxygenator unit 100 includes a main body 110, an expansion member 120, a plurality of hollow fibers 130, and a check valve 150.

[26] The main body 100 includes an inner housing 111 and an outer housing 112.

[27] The inner housing 111 is a cylindrical body having a predetermined diameter. An inflow pipe 113 is formed tangentially along a lower outer circumference of the inner housing 100 so that the blood is introduced therethrough in a tangential direction, and an discharge pipe 114 is formed tangentially on an upper outer circumference so that the blood is discharged therethrough in a tangential direction. More specifically, two inflow pipes 113 may be formed on the lower outer circumference of the inner housing 111 at equal interval, and two discharge pipes 114 may be formed on the upper outer circumference of the inner housing 111 at equal interval. Meanwhile, the inner housing 111, the inflow pipe 113, and the discharge pipe 114 may be formed integrally with each other, and made from urethane which has a predetermined elasticity to enable expansion and contraction. The upper portion of the inner housing 111 is engaged with a first cover 116 having an oxygen inlet 116a so that the oxygen is introduced and discharged therethrough, and also engaged with a second cover 117 having a gas outlet 117a formed on a lower portion so that excessive gas is discharged therethrough after the blood is oxygenated. The outer housing 112 is at a predetermined distance apart from the outer circumference of the inner housing 111, and wraps around the expansion member 120. The outer housing 112 is made from a non-flexible plastic material.

[28] The expansion member 120 is a balloon which is inflated as the air is introduced thereinto, and provided between the outer and inner housings 112, 111. If the expansion member 120 is inflated with air, the expansion member 120 is supported on the outer housing 112 which is made from non-flexible plastic material, to press the inner housing 111 to a contracted state. As a result, blood within the inner housing 111 is discharged out through the discharge pipe 114.

[29] If the expansion member 120 is deflated, the inflow pipe 113 is returned to the original state due to elastic recovery force, and then the inner housing 111 is returned to the original state due to elastic recover force. Accordingly, a vacuum pressure is generated inside the inner housing 111, drawing the blood into the inner housing 111 through the inflow pipe 113. By the periodic contraction/relaxation (that is, pumping movement) of the inner housing 111 due to the expansion member 120, the blood is externally drawn out of the patient's heart and circulated.

[30] A plurality of hollow fibers 130 are densely formed along the lengthwise direction of the inner housing 111. Accordingly, oxygen is introduced into the inner housing 111 through the oxygen inlet 116a of the first cover 116 engaged with the upper portion of the inner housing 111, passed through the hollow fibers 130, and discharged out through the gas outlet 117a of the second cover 117.

[31] A pneumatic pump 140 is provided to enable the expansion member 120 to expand.

Meanwhile, the expansion member 120 may be applied as a fluidic pump which is capable of expanding. Although not mentioned in the following description, a valve may be provided to control an air flow moving from the pneumatic pump 140 to the expansion member 120.

[32] The check valve 150 is a valve that permits flow in one direction only, and applied in the embodiment of the present invention to control a blood flow moving through the inflow pipe 113 and the discharge pipe 114. The check valve 150 includes a first check valve 151 and a second check valve 153. More specifically, the first check valve 151 may be formed on a pair of inflow pipes 113 respectively, and the second check valve 153 may be formed on a pair of discharge pipes 114 respectively. The first check valves 151 may permit the blood flow in a direction in which the blood is introduced into the inner housing 111 through the inflow pipe 113, while the second check valves 153 may permit the blood flow in a direction in which the blood is discharged out of the inner housing 111 through the discharge pipe 114.

[33] Referring to FIG. 4, the blood tube 200 includes a vein tube 200a and an artery tube

200b. One end of the vein tube 200a is connected to the vein of the patient's heart, while the opposite end is divided into two branches which are connected to the two inflow pipes 113. One end of the artery tube 200b is divided into two branches which are connected to the two discharge pipes 114, and the opposite end is connected to the artery of the patient's heart. Once drawn out of the patient's heart, the blood has the decreasing temperature. Accordingly, the heat exchanger 300 is provided on the artery tube 200b to recover the temperauture of the blood before the blood is delivered to the artery of the heart.

[34] According to an aspect of the present invention, the oxygen storage 400 is connected to the oxygen inlet 116a of the first cover 116 to supply oxygen to the oxygenator unit 100. A general oxygen tank or oxygen generator may be applied as the oxygen storage 400.

[35] The operation of the pulsatile cardiopulmonary auxiliary device 10 according to the exemplary embodiments of the present invention will be explained below with reference to FIGS. 2 to 4. FIG. 2 illustrates the oxygenator unit 100 in which the expansion member 120 is in an initial state, that is, in a state in which the expansion member 120 is yet to be expanded, and FIG. 3 illustrates the oxygenator unit 100 in which the expansion member 120 is expanded.

[36] If a patient is in a critical condition and it is necessary to use a pulsatile cardiopulmonary auxiliary device 10 during a cardiac surgery, a vein of the patient's heart is connected to the vein tube 200a and the artery is connected to the artery tube 200b.

[37] As the pulsatile cardiopulmonary auxiliary device operates, the oxygen storage 400 discharges oxygen, so that the oxygen is discharged out through the oxygen inlet 116a, the hollow fibers 130, and the gas outlet 117a. Since the pulsatile cardiopulmonary auxiliary device 10 starts operation, the oxygen storage 400 continuously supplies the oxygenator unit 100 with the oxygen and stops the supply when the pulsatile cardiopulmonary auxiliary device 10 stops operation. The pneumatic pump 140 injects air into the expansion member 120 so that the expansion member 120 can expand and contract periodically. Accordingly, the inner housing 111 repeats expansion and contraction periodically. If the expansion member 120 expands, the inner housing 111 contracts, causing the blood therein to be discharged through the discharge pipe 114. If the expansion member 120 contracts, the inner housing 111 is returned to the original state due to elastic recovery force, causing the blood to be introduced into the inner housing 111 through the inflow pipe 113. As the blood is discharged and introduced repeatedly according to periodic contraction and expansion of the inner housing 111, pumping operation is carried out, and the blood is drown out of the patient's heart and circulated back.

[38] More specifically, if the expansion member 120 expands, the inner housing 111 contracts, causing the blood therein to be discharged through both the inflow pipe 113 and the discharge pipe 114. Herein, since the first check valve 151 does not permit the blood flow in a direction toward the inner housing 111, the inflow pipe 113 is blocked, and the blood is discharged only through the discharge pipe 114. After being discharged, the blood circulates via the artery tube 200b, the heat exchanger 300, and artery tube 200b, and thus flows back to the inside of the heart through the artery.

[39] If the expansion member 120 contracts, causing the inner housing 111 to return to the original state due to elastic recovery force thereof, a vacuum pressure is generated inside the inner housing 111, thereby drawing blood into the inner housing 111 through both the inflow pipe 113 and the discharge pipe 114. However, since the second check valve 153 does not permit the blood flow in a direction in which the blood is introduced into the inner housing 111, the discharge pipe 114 is blocked, and the blood is passed only through the inflow pipe 113 and introduced into the inner housing 111.

[40] As a result, blood circulates according to the periodic contraction and expansion of the inner housing 111.

[41] Hereinbelow, a method of supplying oxygen to the blood inside the inner housing

111 will be explained. The blood is introduced into the inner housing 111 through the inflow pipe 113, and discharged through the discharge pipe 114. The blood contacts the hollow fibers 130 arranged in the inner housing 111, and the oxygen from the oxygen storage 400 is passed through the inner housing 111 through the interior of the hollow fibers 130. Since the oxygen flows inside the hollow fibers 130 and the blood is in contact with the exterior of the hollow fibers 130, the oxygen inside the hollow fibers 130 are absorbed into the blood on the exterior, due to a difference of oxygen concentration. As a result, the blood is supplied with the oxygen, and the carbon dioxide of the blood is discharged to the plurality of hollow fibers 130. After the blood is oxygenated in a manner described above, the temperature of the blood is increased to appropriate degrees at the heat exchanger 300, and the blood is introduced into the patient's heart via the artery tube 300b and the artery. Accordingly, the artificial lung function and blood circulation function are completed.

[42] As explained above, compared to a conventional cardiopulmonary auxiliary device which employs a roller type pump, the present invention employs an expansion member 120 which causes the inner housing 111 to contract and expand (that is, to pump) periodically, and thus provides smooth blood circulation. Additionally, since pumping is carried out without a contact with the blood tubes 200, the blood tubes 200 are not damaged and thus can have a longer lifespan.

[43] Compared to a conventional roller type pump which presses the tubes, the pumping according to an aspect of the present invention involves periodic contraction and expansion of the inner housing 111. Therefore, blood damage does not occur.

[44] Furthermore, since the pulsatile cardiopulmonary auxiliary device 10 according to an aspect of the present invention is provided with an integrated module which is the oxygenator unit 100 to perform blood pumping and oxygenating, the structure is simpler.

[45] Furthermore, since the inflow pipe 113 and the discharge pipe 114 of the oxygenator unit 100 are formed tangentially on the inner housing 111, blood flows smoothly as the blood is introduced or discharged. Industrial Applicability

[46] The present invention relates to a pulsatile cardiopulmonary auxiliary device, and more particularly, to a pulsatile cardiopulmonary auxiliary device having an artificial heart function unit to externally circulate patient's blood flow, and an artificial lung function unit to oxygenate the circulated blood flow.

Claims

[1] A pulsatile cardiopulmonary auxiliary device for externally circulating a blood from a human heart, and supplying an oxygen to the circulating blood, the pulsatile cardiopulmonary auxiliary device comprising: an oxygenator unit to not only circulate the blood, but also oxygenate the blood, the oxygenator unit comprising, a main body, a plurality of hollow fibers arranged inside the main body, and an expansion member to periodically contract/expand the main body, thereby pumping the blood from the human heart to circulate, wherein if the blood is introduced into the main body, the blood is in contact with an external surface of the hollow fibers and supplied with the oxygen passing through an interior of the hollow fibers.

[2] The pulsatile cardiopulmonary auxiliary device of claim 1, further comprising an oxygen storage in fluid communication with the hollow fibers to supply the oxygen to the blood, and a pneumatic pump to inject the air to the expansion member periodically.

[3] The pulsatile cardiopulmonary auxiliary device of claim 2, wherein the main body comprises a cylindrical inner housing made from a flexible urethane; and an outer housing arranged a predetermined distance away from the inner housing, and having the expansion member arranged therein, the outer housing supporting the expansion member to contract/expand the inner housing periodically according to inflation and deflation of the expansion member.

[4] The pulsatile cardiopulmonary auxiliary device of claim 3, wherein a flexible inflow pipe is formed on a lower outer circumference of the inner housing to receive a flow delivered from the human heart, and a flexible discharge pipe is formed on an upper circumference of the inner housing to discharge the received blood, wherein the inflow pipe and the discharge pipe are formed on the inner housing in a tangential direction.

[5] The pulsatile cardiopulmonary auxiliary device of claim 4, wherein the inflow pipe and the discharge pipe are provided with a check valve to control a blood flow, wherein the check valve comprises, a first check valve formed on the inflow pipe to permit the blood flow only in a direction in which the blood is introduced into the inner housing, and a second check valve formed on the discharge pipe to permit the blood flow only in a direction in which the blood is discharged out of the inner housing.