JP2006346440A - Artificial pump driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain miniaturization of the entire device by simplifying the structure and control. <P>SOLUTION: An artificial pump driving device 1 operates a piston 112 back and forth by transmitting rotary driving force generated by a motor 12 through a reducer 14 and a non-circular gear mechanism 15 to the crank shaft 115 of an air cylinder mechanism 11. Thus, the air cylinder mechanism 11 repeats the discharge and suction of air, and by transmitting the discharge and suction of the air through an air hose 16 to an air chamber 23 on the primary side of a blood pump 2, the blood pump 2 is directly driven. A pressure pattern generated by the air cylinder 11 is imparted by the shape of the gear of the non-circular gear mechanism 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an artificial pump driving device for driving an artificial pump such as a blood pump used for an artificial heart or the like, or a balloon pump for assisting a heart function.

  Conventionally, an auxiliary artificial heart has been used for patients with advanced heart failure. This auxiliary artificial heart is disclosed in, for example, Patent Document 1 and the like, and includes a blood pump 2 and an artificial pump driving device 5 for driving the blood pump 2 as shown in FIG. The artificial pump driving device 5 includes a hydraulic pump 52 for driving the blood pump 2, and transmits the driving force by the hydraulic pump 52 to the blood pump 2 via the isolator 51. The internal space of the isolator 51 is defined into a primary side chamber 512 and a secondary side chamber 513 by a diaphragm 511 made of flexible fluoro rubber or the like. The primary side chamber 512 of the isolator 51 is sealed with a liquid medium such as silicon oil having a low viscosity and little influence on the living body, and the secondary side chamber 513 of the isolator 51 is sealed with air.

  The hydraulic pump 52 sends the liquid medium from the second port 521b to the reserve pump 54 via the pipe 62 by rotating the impeller 520 alternately in the direction indicated by A and the direction indicated by B in the figure by the motor 523. The suction period and the pumping period during which the liquid medium is sent from the first port 521a to the primary chamber 512 of the isolator 51 through the pipe 51 are repeated. During the suction period, the volume of the primary side chamber 512 of the isolator 51 is reduced, and the volume of the secondary side chamber 513 is expanded. Although the secondary side chamber 513 is depressurized as its volume is expanded, this pressure decrease is transmitted to the fluid chamber 23 of the blood pump 2 via the pipe 63, and the fluid chamber 23 is depressurized to reduce the volume. Blood is fed into the chamber 24. On the other hand, in the ejection period, the volume of the primary side chamber 512 of the isolator 51 is expanded, and the volume of the secondary side chamber 513 is reduced. As the volume of the secondary side chamber 513 increases, the pressure increases, but this increase in pressure is transmitted to the fluid chamber 23 of the blood pump 2 via the pipe 63, and the fluid chamber 23 increases the pressure to expand the volume. Blood is pumped out of the chamber 24.

A primary side pressure sensor 64 is attached to the primary side chamber 512 of the isolator 51, and a secondary side pressure sensor 65 is attached to the secondary side chamber 513. The pressure in the primary chamber measured by the primary pressure sensor 64 and the pressure in the secondary chamber measured by the secondary pressure sensor 65 are transmitted to the control circuit 53. Based on the pressure detected by the sensors 64 and 65, the control circuit 53 determines the rotational direction of the motor 523 of the hydraulic pump 52 and the secondary pressure of the isolator 51 so as to draw a special pressure curve required for the blood pump. The rotational speed is controlled and the intake / exhaust open / close valve 66 is controlled to open / close. In the case of a blood pump, the pressure curve is a curve in which the positive pressure period is shorter than the negative pressure period and the peak value of the positive pressure period is larger than the peak value of the negative pressure period.
JP 2003-70906 A (paragraphs 0016 to 0024, FIGS. 1 and 17)

  In the case of the artificial pump driving device as described above, it is desirable that the artificial pump driving device is as small as possible in consideration of portability. However, in the above-described conventional artificial pump drive device, in order to adjust to a special pressure curve, the hydraulic pump is rotated forward and backward to reciprocate the liquid medium between the isolator and the reserve pump. The configuration of the hydraulic pump is complicated, and the control of the hydraulic pump by the control circuit is also complicated. For this reason, there exists a problem that size reduction of the whole apparatus cannot be achieved.

  The present invention has been made in view of these points, and an object of the present invention is to provide an artificial pump drive device that is simple in structure and control and can be downsized as a whole.

  The artificial pump driving device according to the present invention is connected to the primary side of the artificial pump so that the pressure on the primary side of the artificial pump has a predetermined pressure pattern in which a positive pressure process and a negative pressure process are alternately repeated. In an artificial pump driving device that drives the artificial pump by repeating discharge and suction of fluid, a motor that rotates a rotating shaft at a constant predetermined speed is connected to the rotating shaft of the motor directly or via a speed reducer. A non-circular gear mechanism, a crankshaft that is rotationally driven by the rotational driving force of the motor transmitted through the noncircular gear mechanism, a piston that is connected to the crankshaft and reciprocates, and an internal piston. And a driving fluid chamber in which one end of the cylinder is closed and the driving fluid is accommodated together with the cylinder and the piston. And a cylinder cover having an input / output port for the drive fluid and a drive fluid path connected to the input / output port of the drive fluid chamber to communicate the drive fluid chamber and the primary side of the artificial pump. And the non-circular gear mechanism provides the predetermined pressure pattern which is a peak value and a time ratio of the positive pressure process and the negative pressure process preset on the primary side of the artificial pump. As described above, the piston is configured by a plurality of non-circular gears configured to drive the piston.

  The predetermined pressure pattern is, for example, a pressure pattern in which the negative pressure process has a longer period than the positive pressure process and the peak value becomes smaller.

  In one embodiment of the present invention, a negative pressure control valve is provided that is connected to the driving fluid chamber and introduces the driving fluid into the driving fluid passage when the negative pressure in the driving fluid chamber exceeds a predetermined pressure. . In another embodiment of the present invention, there is provided a positive pressure control valve that is connected to the driving fluid chamber and discharges the driving fluid from the driving fluid passage when the positive pressure in the driving fluid chamber exceeds a predetermined pressure. I have.

  In addition, it is desirable to provide a check valve in series with each of the positive pressure control valve and the negative pressure control valve.

  In still another embodiment of the present invention, a pressure sensor for detecting the pressure on the primary side of the artificial pump, and a positive pressure and a negative pressure on the primary side of the artificial pump are previously determined from the pressure detected by the pressure sensor. The apparatus further includes determination means for determining whether the set value has been reached and whether or not the preset upper limit value and lower limit value have been exceeded, and display means for displaying the determination result of the determination means.

  According to the present invention, the rotational driving force of the motor is transmitted to the piston through the non-circular gear mechanism, and the fluid cylinder mechanism including the piston, the cylinder, and the cover repeatedly discharges and sucks the driving fluid. Direct drive. The pressure pattern at that time is given by the shape of the non-circular gear. Therefore, according to the present invention, as in the prior art, an isolator driven by a liquid medium is interposed between the hydraulic pump and the artificial pump, a reserve pump is provided, or the motor is driven back and forth according to a predetermined speed pattern. Therefore, a control mechanism is not required at all, and the apparatus can be greatly reduced in size.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration of an artificial pump driving device according to an embodiment of the present invention. 2A and 2B are diagrams showing the main part of the apparatus, wherein FIG. 2A is a cross-sectional view (partially a cross-sectional view taken along the line AA 'in FIG. It is sectional drawing.

  This artificial pump drive device 1 is connected to the primary side of a blood pump 2 which is an artificial pump, and directly drives the blood pump 2 with a predetermined pressure pattern. The artificial pump drive device 1 includes an air cylinder mechanism 11 and a motor 12 that is a drive source of the air cylinder mechanism 11.

  The air cylinder mechanism 11 is a cylindrical piston 111 in which a cylindrical piston 112 is coaxially disposed so as to reciprocate along the axis of the cylinder 111. A rectangular crankcase 113 is provided on the base end side of the cylinder 111, and a crankshaft 115 is rotatably supported by bearings 114 extending inward from both side surfaces of the crankcase 113. The crankshaft 115 has a crankpin 116 at an eccentric position, and the crankpin 116 and the piston 112 are connected via a connecting rod 117. A cylinder cover 119 is provided on the distal end side of the cylinder 111 so as to close the distal end of the cylinder 111 and form an air chamber 118 together with the cylinder 111 and the piston 112 and an air input / output port 119a.

  The motor 12 rotates at a constant speed at a speed set by the rotation speed setting unit 13. The motor 12 is connected to a speed reducer 14 that reduces the rotational speed. The rotational driving force output from the speed reducer 14 is transmitted to one end of the crankshaft 115 that protrudes outside through the side surface of the crankcase 113 via the non-circular gear mechanism 15. The non-circular gear mechanism 15 is a combination of two non-circular gears 151 and 152 at a predetermined relative angle, and is formed in a shape for driving the piston 112 so as to give a predetermined pressure pattern to the primary side of the blood pump 2. Has been.

  Between the air input / output port 119a of the cylinder cover 119 and the primary side of the blood pump 2, a flow path of air that is a driving fluid that communicates between the air chamber 118 of the air cylinder mechanism 11 and the primary side of the blood pump 2 is provided. The air hose 16 to be formed is connected. A branch hose 17 that branches from the air hose 16 is connected to the air hose 16, and a negative pressure control valve 18 and a positive pressure control valve 19 are connected to the tip of the branch hose 17. The negative pressure control valve 18 introduces air from the atmosphere into the air hose 16 when the air pressure in the air hose 16 falls below a predetermined pressure. The positive pressure control valve 19 releases air to the atmosphere when the air pressure in the air hose 16 exceeds a predetermined pressure.

  The blood pump 2 includes a housing 21 and a diaphragm 22 attached in the housing 21. A space in the housing 21 is divided into a primary air chamber 23 and a secondary blood chamber 24 by the diaphragm 22. The blood chamber 24 is provided with a suction port 25 and a discharge port 26 with a check valve connected to a human blood vessel.

  Next, the operation of the artificial pump driving apparatus according to this embodiment configured as described above will be described.

  When the target rotational speed is set by the rotational speed setting device 13, the motor 12 rotates the rotating shaft at a constant speed at the set rotational speed by the operation of an internal rotation control circuit (not shown). This rotation is transmitted to the crankshaft 115 via the speed reducer 14 and the non-circular gear mechanism 15. When the crankshaft 115 rotates, the piston 112 reciprocates within the cylinder 111. By the reciprocating motion of the piston 112, the air cylinder mechanism 11 repeatedly discharges and sucks air through the air input / output port 119a, and reciprocates the diaphragm 22 of the blood pump 2 in conjunction with this.

  FIG. 3 shows each part in a state where the piston 112 is at bottom dead center (a), the crankshaft 115 is rotated 90 degrees (b), the piston 112 is top dead center (c), and the crankshaft 115 is rotated 270 degrees (d). The positional relationship is shown. Until the piston 112 rises from the bottom dead center (a) to the top dead center (c), the non-circular gears 151 and 152 drive the piston 112 at a high gear ratio at a high gear ratio. Until the bottom dead center (a), the non-circular gears 151 and 152 drive the piston 112 at a low speed with a small gear ratio.

  Thereby, the pressure pattern of the air chamber 23 of the blood pump 2 becomes a pressure pattern as shown in FIG. In this pressure pattern, a positive pressure process in which the peak value is about 250 mmHg and a negative pressure process in which the peak value is about −50 mmHg are alternately repeated, and the positive pressure process has a shorter period than the negative pressure process. It is. For reference, a pressure pattern of a prior art device and a pressure pattern along a sine wave are shown.

  Since the piston 112 and the inner peripheral surface of the cylinder 111 slide during the operation of the air cylinder mechanism 11, the air in the air chamber 118 slightly leaks during this sliding. When the air leaks, the amount of air for driving the diaphragm 22 of the blood pump 2 decreases, so that it is difficult to link the reciprocating motion of the piston 112 and the reciprocating motion of the diaphragm 22 of the blood pump 2. Therefore, the negative pressure control valve 18 operates when the degree of vacuum becomes higher than a certain vacuum pressure and takes in the atmospheric pressure into the air hose 16 to prevent a decrease in the air amount. Thereby, the reciprocating motion of the piston 112 and the diaphragm 22 can be linked.

  In particular, in the case of a blood pump for an artificial heart, when the suction pressure becomes negative from −50 mmHg, a sticking phenomenon occurs in which the heart wall sticks to the cannula. For this reason, it is necessary to control the negative pressure with the negative pressure control valve 18 so that the blood pump 2 does not become a high vacuum.

  Moreover, since the chamber effect is acquired when the air hose 16 is lengthened, for example to 360 cm or more, the peak vacuum pressure rise can also be suppressed by this.

  The negative pressure control valve 18 also has a function of preventing high vacuum when the air hose 16 is accidentally crushed.

  On the other hand, if the air hose 16 connecting the air cylinder mechanism 11 and the blood pump 2 is accidentally disconnected, the positive pressure in the air hose 16 becomes abnormal after the air hose 16 is connected again. The positive pressure control valve 19 operates in such a case to prevent the air chamber 23 from exceeding a predetermined pressure, although it is expected to become higher. Thereby, even when the air hose 16 is disconnected, the reciprocating motion of the piston 112 and the reciprocating motion of the diaphragm 22 are immediately linked by simply reconnecting the air hose 16 without turning off the power of the motor 12. It becomes like this.

  In the case of a blood pump for an artificial heart, it is necessary to set the blood discharge pressure to around 250 mmHg. Therefore, the positive pressure control valve 19 is set to have such a pressure.

  Also in this case, the positive pressure control valve 19 also has a function of preventing high pressure when the air hose 16 is accidentally crushed.

  FIG. 5 is a diagram showing another embodiment of the present invention.

  In this embodiment, check valves 31 and 32 are connected in series to the negative pressure control valve 18 and the positive pressure control valve 19, respectively.

  According to this embodiment, it is possible to prevent a problem that air is released to the atmosphere via the negative pressure control valve 18 or air is introduced into the air hose 16 via the positive pressure control valve 19.

  FIG. 6 is a diagram showing still another embodiment of the present invention.

  In this embodiment, the negative pressure and the positive pressure on the primary side of the blood pump 2 reach the negative pressure set value NS and the positive pressure set value PS, respectively, and exceed the lower limit positive pressure NM and the upper limit positive pressure PM, respectively. This is different from the previous embodiment in that a controller 4 for detecting whether or not there is a controller is provided.

  The controller 4 includes a pressure sensor 41 and a pressure sensor 42 that respectively detect a positive pressure and a negative pressure on the primary side of the blood pump 2 via a branch hose 17 a further branched from the branch hose 17, and a pressure detected by the pressure sensor 41. A comparator 43 that compares the positive pressure set value PS and the upper limit positive pressure value PM, and a comparator 44 that compares the pressure detected by the pressure sensor 42 with the negative pressure set value NS and the lower limit negative pressure value NM, A display 45 for displaying the primary pressure state of the blood pump 2 based on the comparison results of the comparators 43 and 44 is provided. The negative pressure control valve 18 and the positive pressure control valve 19 are provided with pressure adjusting knobs 18a and 19a, respectively. The negative pressure set value NS and the positive pressure set value PS given to the controller 4 may be inputted in conjunction with the set values by the knobs 18a and 19a, respectively, or may be inputted separately.

  According to the artificial pump driving device configured in this way, as shown in FIG. 7, the positive pressure on the primary side of the blood pump 2 has reached the positive pressure set value PS, and has exceeded the upper limit positive pressure value PM. The controller 4 detects that the negative pressure on the primary side of the blood pump 2 has reached the negative pressure set value NS and does not exceed the lower limit negative pressure value NM, and displays on the display 45. can do. Therefore, by adjusting the knobs 18a and 19a of the negative pressure control valve 18 and the positive pressure control valve 19 while confirming the display on the display 45 of the controller 4, the pressure setting and adjustment on the primary side of the blood related pump 2 are performed. And it is possible to easily confirm that the blood pump 2 is always driven at an optimum pressure.

  In the above embodiment, the controller 4 uses the two pressure sensors 41 and 42 and the two comparators 43 and 44. However, the pressure sensor detected by the pressure sensor is integrated into one pressure sensor. The peak value of the positive pressure and the negative pressure may be detected from the maximum value and the minimum value, and compared with the pressure set value and the limit value inside the computer.

It is a figure which shows the structure of the artificial pump drive device which concerns on one Embodiment of this invention. It is a figure which shows the principal part of the apparatus, (a) is sectional drawing (a part is AA 'sectional drawing of (b)), (b) is BB' sectional drawing of (a). It is a figure for explaining operation of the device. It is a graph which shows the pressure waveform of the apparatus. It is a figure which shows the structure of the artificial pump drive device which concerns on other embodiment of this invention. It is a figure which shows the structure of the artificial pump drive device which concerns on other embodiment of this invention. It is a graph which shows the pressure waveform of the apparatus. It is a figure which shows the structure of the conventional artificial pump drive device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,5 ... Artificial pump drive device, 2 ... Blood pump, 4 ... Controller, 11 ... Air cylinder mechanism, 12 ... Motor, 13 ... Speed setting device, 14 ... Reduction gear, 15 ... Non-circular gear mechanism, 16 ... Air Hose, 17 ... branch hose, 18 ... negative pressure control valve, 19 ... positive pressure control valve, 41, 42 ... pressure sensor, 43, 44 ... comparator, 45 ... indicator, 111 ... cylinder, 112 ... piston, 113 ... Case, 115 ... crankshaft, 117 ... connecting rod.

Claims (7)

By repeating the discharge and suction of the driving fluid so that the pressure on the primary side of the artificial pump connected to the primary side of the artificial pump has a predetermined pressure pattern that alternately repeats the positive pressure process and the negative pressure process. In the artificial pump driving device for driving the artificial pump,
A motor that rotates the rotating shaft at a constant predetermined speed;
A non-circular gear mechanism connected to the rotating shaft of the motor directly or via a reduction gear;
A crankshaft that is rotationally driven by the rotational driving force of the motor transmitted through the non-circular gear mechanism;
A piston connected to the crankshaft and reciprocating;
A cylinder that accommodates the piston in a reciprocating manner;
A cylinder cover that closes one end of the cylinder to form a driving fluid chamber in which the driving fluid is accommodated together with the cylinder and the piston and includes an input / output port for the driving fluid;
A drive fluid hose connected to the input / output port of the drive fluid chamber to communicate the drive fluid chamber and the primary side of the artificial pump to form a drive fluid path;
The non-circular gear mechanism is configured to drive the piston so as to apply the predetermined pressure pattern that is a peak value and a time ratio of the positive pressure process and the negative pressure process set in advance on the primary side of the artificial pump. An artificial pump drive device comprising a plurality of non-circular gears.   2. The artificial pump driving device according to claim 1, wherein the predetermined pressure pattern is a pressure pattern in which the negative pressure process has a longer period than the positive pressure process and a peak value becomes smaller.   3. A negative pressure control valve that is connected to the driving fluid chamber and introduces the driving fluid into the driving fluid passage when the negative pressure of the driving fluid chamber exceeds a predetermined pressure. The artificial pump drive described.   4. A positive pressure control valve that is connected to the driving fluid chamber and discharges the driving fluid from the driving fluid passage when the positive pressure of the driving fluid chamber exceeds a predetermined pressure. The artificial pump drive device according to any one of the above.   4. The artificial pump drive device according to claim 3, further comprising a first check valve connected in series with the negative pressure control valve and allowing the drive fluid to flow only in a direction of introducing the drive fluid into the drive fluid chamber.   5. The artificial pump drive device according to claim 4, further comprising a second check valve connected in series with the positive pressure control valve and allowing the drive fluid to flow only in a direction of discharging from the drive fluid chamber. A pressure sensor for detecting the pressure on the primary side of the artificial pump;
It is determined from the pressure detected by this pressure sensor whether the positive pressure and negative pressure on the primary side of the artificial pump have reached preset values and whether preset upper and lower limits have been exceeded. A determination means;
The artificial pump drive device according to any one of claims 1 to 6, further comprising display means for displaying a determination result of the determination means.

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