Catheter pump

Abstract

To secure stable operation with a small liquid loss in a catheter pump.SOLUTION: A catheter pump includes a hollow catheter and a blood pump provided at a distal end of the hollow catheter. The hollow catheter has a feeder for feeding a conduit (8) extending between the distal end and a proximal end of the hollow catheter with liquid. The feeder has diaphragm pumps (10, 19), a magnetic device (10a), and a controller (11). The magnetic device (10a) operates the diaphragm pumps (10, 19) by a magnetic force. The controller (11) drives the magnetic device (10a) by generated pulse, adjusts flow rate and / or pressure generated by the diaphragm pumps (10, 19) by pulse frequency and stroke. The hollow catheter includes a shaft (2) arranged in the conduit (8). The liquid is used for flash the shaft (2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention belongs to the fields of electrical engineering and mechanics and can be used with particular advantage in the field of medical engineering.

[0002] In particular, the present invention relates to the supply of a liquid to a conduit. For example, filling a conduit with a liquid may be necessary to cool the walls of the conduit, or to cool or lubricate moving parts arranged in the conduit and / or to keep these parts gas-free. For this purpose, it is known in principle to supply such conduits, for example cannulas, with a cooling and / or lubricating liquid. The liquid may in principle be moved into or through the conduit by a pump. [Background technology]

[0003] Here, particularly for medical applications, it is often important that, on the one hand, there are no wear parts manufactured into the conduit and carried by the liquid within the conduit, and, on the other hand, the speed at which the liquid is moved within the conduit is as slow as possible but precisely controlled. In addition to this, it may be desirable to minimize the loss of liquid from the conduit.

[0004] For example, prior art such as U.S. Patent No. 5,949,663 discloses a heat exchange system having a pump for transporting heat exchange fluid to and from a catheter. A flow detector in the form of an impeller wheel is described, the rotational speed of which corresponds to the flow rate as it is moved by the heat exchange fluid. The speed of the impeller wheel is measured externally by a light barrier, which is interrupted each time an individual blade of the impeller wheel passes through said barrier.

[0005] A medical membrane pump is known from US Pat. No. 5,629,999, which is used to deliver insulin in small amounts, and which also describes a pulsatile delivery mode.

[0006] US Patent No. 5,649,999 discloses a method for flushing a catheter with a return conduit to the outside, thereby minimizing deposits inside the catheter as much as possible. Among other things, it describes a pulsed flush, which can be controlled by a solenoid valve. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Utility Model No. 20 2005 021 999 U1 [Patent Document 2] Former East German Patent No. 202 805 A1 [Patent Document 3] German patent no. 694 09 587 T2 Summary of the Invention [Problem to be solved by the invention]

[0008] Against the background of the prior art, the object of the present invention is therefore to devise a supply device for supplying liquid to a conduit and a method of operating such a supply device, where a solution of simple design is required that allows the flow of liquid to be controlled in a controlled manner at low flow rates. [Means for solving the problem]

[0009] This object is achieved according to the invention by a feeding device and a method according to the independent claims. Specific embodiments are set forth in the dependent claims.

[0010] The invention therefore relates to a method for operating a supply device for supplying a liquid to a conduit and comprising a membrane pump, characterized in that the membrane pump is controlled in terms of the pressure generated and / or the delivery rate.

[0011] According to the invention, there is also proposed a supply device for supplying a liquid to a conduit, the device comprising at least one membrane pump, the device comprising a control device for controlling the pump in terms of the generated pressure (which in some embodiments may comprise a negative pressure or vacuum) and / or the delivery rate.

[0012] The invention further relates to hollow catheters and / or catheter pumps, both of which have a delivery device according to the invention for flushing the conduits of the hollow catheter or catheter pump in the manner according to the invention.

[0013] One embodiment relates to the fact that a correspondingly equipped hollow catheter has a rotatable shaft within the hollow catheter (preferably within the conduit).

[0014] According to another embodiment, a rotatable shaft also passes through the catheter pump, which preferably includes a hollow catheter according to the present invention. Here, it is advantageous if this controllable shaft is flexible. Regarding the example of a left ventricular assist system inserted into the ventricle via the femoral artery and advanced until it reaches the left ventricle, this means that such a pump includes a rotatable shaft, which is driven outside the body to drive a rotor within the heart; this shaft must be flexible enough to follow the curvature of, for example, the aortic arch, yet still be able to rotate at high speeds. The rotatable shaft within the lumen / conduit to be flushed should be able to operate at high rotational speeds, for example, greater than 10,000 revolutions per minute.

[0015] The supply device according to the invention now makes it possible to reliably supply liquid via the supply device according to the invention, for example to ensure that no air is present in the hollow catheter or catheter pump, as well as to lubricate the flexible shaft.

[0016] The invention also relates to a method for operating a supply device for supplying a liquid to a conduit and having two pumps arranged at mutually distant points in the conduit, wherein the parameter values ​​of at least one operating parameter of both pumps are controlled in a mutually coordinated manner.

[0017] In principle, it is known and possible to move liquids through conduits by means of syringe pumps, but the features of the present invention, in particular the use of multiple pumps, allow the operating parameters of the pumps to be adjusted to one another, so that an appropriate pressure difference can be maintained between the intake and exhaust regions of the conduits, for example, while setting a common pressure level.

[0018] By means of two regulated pumps, it is possible, on the one hand, to set a specific flow rate through the conduit, and, on the other hand, to control the flow rate in such a way that the loss rate in the inlet and outlet areas or in case of leaks / openings in the conduit can be set and in particular limited to specific values.

[0019] In order to make it possible to adjust and therefore control the operation of the delivery device particularly well, membrane pumps are particularly suitable for producing delivery devices, which can be controlled particularly precisely and reproducibly in terms of flow, i.e., flow rate.

[0020] A particularly efficient control of the supply device is possible if the liquid pressure is advantageously detected at two points in the conduit that are spaced apart from one another. In particular, the points at which the liquid pressure is detected can each be assigned to one of the pumps, and the pressure detection allows the ratio of suction pressure to overpressure to be optimized in the control of the pumps. Such control is particularly important when the conduit is not closed in a ring shape and has a suction area where liquid is fed into the conduit from an external liquid reservoir and / or a discharge conduit where liquid is removed from the conduit to a collection reservoir.

[0021] The corresponding pressure sensors can be mounted separately in the conduits, but one may also be incorporated into each of the pumps.

[0022] In the case of the method according to the invention, it has proven to be particularly advantageous if the adjusted parameter values ​​of the two pumps are variable over time in a regular manner, and in particular periodically for a period after the start-up period. For example, the capacity of at least one of the pumps can be slowly increased during the start-up period. However, the capacity peak (performance peak) may also be determined initially when the liquid flows through the conduit at a high flow rate, which then decreases again after the start-up period.

[0023] Regardless of the configuration of the start-up period, the pressure of at least one of the pumps can be controlled to periodically increase and decrease, or the flow rate can be set to increase and decrease accordingly. This is particularly advantageous when moving parts are installed in the conduit, such as a driveable shaft in a cannula that can itself release small particles due to friction. These particles should generally not be moved further along the conduit, but liquid should be transported regardless. By varying the operating parameters of the pump, the conduit can be efficiently flushed with liquid, so that all parts of the conduit are reached by the fluid flow. Periods of slower liquid flow rate allow particles to reach stagnant parts of the flow, thereby minimizing particle transport along the conduit.

[0024] The change in the pump parameters can be a change in the capacity (performance) of each individual pump, as well as a change in the capacity (performance) difference or the pressure difference generated by the pumps, which ensures the acceleration of the liquid and therefore causes a periodic fluctuation in the pressure difference and a corresponding periodic fluctuation in the liquid transport.

[0025] Liquid is hereinafter understood to mean the liquid used to flush the shaft. In some exemplary embodiments, this is not the liquid to be pumped, although a small amount or traces of the liquid to be pumped may be in the conduit. In other exemplary embodiments, the liquid delivered by the pump may be the liquid used for flushing.

[0026] According to another advantageous embodiment of the invention, the adjusted parameter values ​​of the two pumps are in a ratio to each other that depends in a predetermined way on the detected value of the liquid pressure in the conduit, in this way the liquid pressure or pressure difference in the conduit can be periodically controlled.

[0027] The delivery capacity of a pump can be determined based on different measured quantities. In some exemplary embodiments, the measured quantities or operating parameters that determine the delivery capacity are the membrane stroke period and / or the membrane stroke height and / or the membrane deflection. Here, one of the above measured quantities or a combination of at least two of the above measured quantities can be examined to determine the delivery capacity. Another thing that can determine the delivery capacity in some exemplary embodiments is the power consumption of the pump, especially taking into account the prevailing liquid pressure.

[0028] The adjusted operating parameters of both pumps may therefore be, for example, their respective delivery capacities, whereby, for example, a specific difference in delivery capacities may also be set between the two pumps, thereby generating, for example, a specific loss rate for the liquid transport over the entire path of the conduit.

[0029] According to another embodiment of the invention, the adjusted operating parameters of both pumps are the respective values ​​of the liquid pressures generated by the pumps. The liquid pressures can be particularly easily and accurately detected in the conduits, whereby, for example, a specific ratio of pressure values ​​or a specific difference in pressure values ​​can be set by the control of the pumps. The ratio and / or the difference can also be set to be periodically variable in order to avoid non-fluid flows with stagnation areas.

[0030] According to another advantageous embodiment of the invention, the adjusted operating parameter of both pumps is their respective power consumption, for which purpose each pump may be assigned an electrical sensor for detecting the power consumption, in particular the current consumption, of the pump.

[0031] Advantageously, the adjusted operating parameter of both pumps may additionally be the respective flow rates of the pumps, which may be detected separately, for example by flow meter sensors, or also by recording the operating parameters of the pumps, for example the power consumption and the prevailing liquid pressure.

[0032] In addition, a constant pressure difference and / or a constant flow rate difference may advantageously be set between the two pumps, where the difference in flow rate between both pumps may in particular be less than 100 milliliters per day, in particular less than 10 milliliters per day, or even less than 1 milliliter per day.

[0033] A corresponding loss rate is set at the opening of the conduit. For example, the conduit may have a transport conduit and a return conduit, the transport conduit terminating in a blood pump, for example located at the end of the cannula, and the return conduit starting at the same point. To compensate for the flow rate difference, part of the liquid may then flow, for example, through the blood pump to flush it, or, in the implanted state, be released into the patient's body. In the development of the present invention, a biocompatible, health-compatible liquid, for example physiological saline, has been selected as the liquid for such applications.

[0034] An advantageous mode of operation of this method may further include reversing the direction of fluid movement. Such reversal of fluid movement may be provided periodically or only in specific circumstances. When used to flush a pump catheter, the direction selected is typically to transport fluid from the proximal end of the catheter to the distal end of the catheter and back through the return conduit to a collection vessel.

[0035] The invention also relates to a method for operating a supply device and to the design of a supply device for supplying a liquid to a conduit, said supply device comprising at least two pumps, in particular membrane pumps, arranged at mutually distant points in the conduit, and also comprising a control device for controlling the pumps individually in terms of the pressure generated and / or the delivery rate.

[0036] The control device must be designed in such a way that it allows coordinated control of the individual pumps. It may be assigned to one of the pumps or formed as a separate central control unit. The control device may also be responsible for adjusting the operating parameters of the pumps and is then connected to sensors for detecting measured values.

[0037] For example, each pump may be assigned a liquid pressure sensor, and the controller may then set a specific pressure ratio between suction pressure and excess pressure, or a specific percentage of the pressures generated by the two pumps, or a specific pressure difference.

[0038] Since the measured quantity for determining the pump's delivery power may depend on the pressure, the pump may, for example, be operated as a pressure sensor if its power consumption is detected and supplied to the control device. However, the power consumption may also be an indicator of the flow rate achieved by the respective pump and may be detected as such. For this purpose, the prevailing liquid pressure is usually also taken into account, so that the simultaneous operation of a pressure measurement sensor is advantageous for this type of operation.

[0039] However, flow rate sensors may also be installed, each assigned to one of the pumps, so that a specific ratio or predetermined difference in the flow rates in that region of the first and second pumps can be set by the control device, and such a difference in flow rate may also be controlled to be periodically variable, for example. [Brief explanation of the drawings]

[0040] [Figure 1] 1 shows a hollow catheter having a drivable shaft and a delivery device according to the present invention. [Figure 2] FIG. 1 is a longitudinal cross-sectional view of the end of a hollow catheter with a rotary pump fixed distally thereto for operation within a blood vessel. [Figure 3] FIG. 1 is a cross-sectional view of a hollow catheter. [Figure 4]FIG. 10 is a cross-sectional view of another hollow catheter. [Figure 5] 10A-10C show a method sequence of a method of operation of the feeding device. [Figure 6] This is a graph showing three variations of the flow velocity over time. [Figure 7] 1 is a graph showing the progression of liquid pressure over time. DETAILED DESCRIPTION OF THE INVENTION

[0041] The invention is illustrated in the drawings and explained below on the basis of an exemplary embodiment.

[0042] 1 shows a hollow catheter in longitudinal cross section, with the proximal end 1a in medical use shown in the lower portion and the distal end 1b in the upper portion. For example, an implantable blood pump may be installed at the distal end of hollow catheter 1 for operation, particularly within blood vessels and / or ventricles.

[0043] A rotatably drivable shaft 2 extends within the hollow catheter 1. It serves, for example, to drive a blood pump and is connected at its proximal end 2a to a drive motor 3. The shaft 2 can be introduced into a connection housing 5 in the region of a feedthrough 4, which is configured in such a way that a seal prevents the medium from penetrating along the shaft into the connection housing 5 or leaking out of the connection housing 5.

[0044] However, a solution is also conceivable in which the rotary drive movement is transmitted through the closed wall of the connecting housing 5 by magnetic coupling, whereby a first magnet element 6 is joined inside the connecting housing to a second magnet element 7 fixed on the end of a shaft connected to the motor 3 outside the connecting housing 5. The shaft 2 is then interrupted between the motor 3 and the part where it extends further into the connecting housing 5, and the corresponding wall of the connecting housing 5 is formed continuously and does not have any openings. In Figure 1, the magnet elements 6, 7 are shown as an alternative in dashed lines.

[0045] The drive shaft 2 is manufactured, for example from Litz wire, in particular in the form of stranded or twisted wires, or formed as a helical spring, or a combination of both by surrounding a core with a helical spring, so that on the one hand it can transmit high rotational speeds of the order of several thousand revolutions per minute, and on the other hand it is flexible during this process.

[0046] To cool such a shaft during operation and, on the other hand, to reduce friction by lubrication, a cooling and lubricating liquid is typically provided in a conduit 8 formed in the hollow catheter 1, which is advantageously biocompatible. The liquid is supplied to the connecting housing 5 through an inlet conduit 9 and transported along the conduit 8. For this purpose, the inlet conduit 9 is connected to a first pump, which in this exemplary embodiment is formed as a membrane pump 10. Membrane pumps in this context have the property of being very reliably and reproducibly controllable, allowing the generated pressure and flow rate to be precisely controlled. The use of a magnetically actuated membrane pump has proven particularly advantageous in this context. Thus, FIG. 1 shows a magnetic device 10a, which serves as a drive means for the membrane pump 10 and is actuated by an electrical control device 11.

[0047] The membrane pump 10 aspirates liquid from the inlet reservoir 12, as indicated by arrow 13, and delivers it at an adjustable flow rate and pressure through the inlet conduit 9 to the connecting housing 5. The liquid expands within the connecting housing 5 and moves, in particular in the direction of arrow 14, along the conduit 8 towards the distal end 1b of the hollow catheter. Movement along the conduit 8 can be assisted, for example, by rotation of the shaft 2, which has an at least partially helical outer shape and rotates in the appropriate rotational direction.

[0048] While the rotation of the shaft 2 may assist in the movement of liquid along the conduit 8, in some exemplary embodiments it is possible to determine the contribution of the shaft rotation to the delivery capacity and adjust the delivery capacity of the pump accordingly. In other words, the delivery capacity provided in consideration of the shaft rotation is compensated for by adjusting the delivery capacity of the pump. The determination of the delivery capacity based on the shaft rotation may then also be interpreted as a disturbance variable, which is compensated for by adjusting the delivery capacity of the pump to ensure that the delivery capacity throughout the conduit is as predetermined. The delivery capacity of the conduit 8 may depend, among other things, on the rotational speed of the shaft, possibly shaft wear, catheter deflection, or others. While these variables can be determined, it is often easier to compensate for the resulting shaft delivery capacity with the pump.

[0049] Typically, flow rates on the order of microliters or milliliters per hour can be set by operating the membrane pump 10 .

[0050] In order to be able to appropriately control or regulate the corresponding flow rate and / or pressure, at least one suitable sensor 15 is installed in the conduit 8 and connected to the control device 11 by a communication line 16. The sensor 15 may for example be formed as a pressure sensor, as a flow rate sensor or as a combined sensor for detecting pressure and flow rate.

[0051] In the illustrated exemplary embodiment, a sensor 15 is assigned to the first membrane pump 10 and detects the pressure and / or corresponding flow rate generated by this first pump.

[0052] 1, the conduit 8 is divided longitudinally into a first conduit region 8a through which the liquid flows in the direction of the arrow 14 from the connection housing 5 towards the distal end 1b of the hollow catheter 1, and a second conduit region 8b formed as a return conduit. The two conduit regions 8a, 8b are therefore connected in series and together form the conduit 8.

[0053] The return conduit 8b may be separated from the first conduit region 8a by a partition wall 17, for example as shown in Figure 3, or the second conduit region / return conduit 8b may be formed by a cannula 18 extending into the hollow catheter 1. A variant of this is shown in cross section in Figure 4.

[0054] 1, the return conduit 8b is configured in such a way that it allows a return flow of liquid into the connecting housing 5 and from there to the second membrane pump 19. The second membrane pump 19 may advantageously be configured as a magnetic membrane pump, which has a magnetic device 19a, which is activated by the control device 11 and forms the drive means of the membrane pump 19. The membrane pump 19 sucks the liquid from the return conduit 8b and guides it via the discharge conduit 20 to the discharge reservoir 21.

[0055] The control device 11 is additionally connected to a second sensor 22, which, like the first sensor 15, can be configured as a flow path sensor and / or a pressure sensor and is assigned to the return conduit 8b and thus to the second membrane pump 19. For example, the flow rate in the return conduit 8b or the suction pressure of the second membrane pump 19 can be detected by the second sensor 22. The parameters detected by the second sensor 22 are supplied to the control device 11 via a second communication line 23.

[0056] The controller 11 itself is connected to a power connector 11a, which supplies the controller with a low DC voltage. The controller 11 generates pulses that are supplied to the magnetic devices 10a, 19a to drive the first and second membrane pumps 10, 19. The flow rate and / or pressure generated by the first and second membrane pumps 10, 19 can be controlled by the frequency and stroke of the pulses generated by the controller 11.

[0057] 2 shows, as an example of the use of a hollow catheter with a drivable shaft, an implantable blood pump 24 formed as a rotary pump having a rotor 25 together with a pumping element. The rotor 25 is directly connected to the shaft 2, which is mounted in a rotary bearing 26 at the distal end of the rotor 25 within the blood pump housing 27. The blood pump 24 draws blood through an inlet 28 at its distal end in the direction of arrows 29, 30 and transports it through the hollow catheter 1 via an annular conduit 32 formed by an outflow tube 31 and into a blood vessel (not shown).

[0058] The shaft 2 is mounted at the end of the hollow catheter 1 in a bush bearing 33, which on the one hand allows high rotational speeds and, on the other hand, can be as tight as possible to prevent or limit fluid exchange along the shaft 2. In particular, blood is prevented from passing from the inside of the housing 27 of the blood pump 24 into the hollow catheter 1, i.e., into the conduit 8.

[0059] 2, partition wall 17 is shown in dashed lines to indicate the separation between first conduit region 8a and second conduit region / return conduit 8b of conduit 8. Thus, liquid inflow through first conduit region 8a towards the distal end of hollow catheter 1 in the direction of arrow 34 and return flow through second region 8b of conduit 8 in the direction of arrow 35 are possible. Rotary shaft 2 can thus be supplied with liquid along its entire length.

[0060] To prevent blood from entering the conduit, an overpressure of the liquid inside the hollow catheter 1, i.e., in the conduit 8, can be established, which allows the liquid to flow at a very low flow rate from the conduit 8 to the housing of the blood pump 24, as indicated by arrows 36, 37. For example, an outflow rate of a few microliters or milliliters per day can be established here, which represents the difference between the supply rate of the first conduit region 8a and the return rate of the return conduit 8b. This difference can be established and measured as the difference in delivery rate between the first pump 10 and the second pump 19.

[0061] A flow diagram of the method of operation of the illustrated dispensing device is shown in Figure 5. In a first step 38, ventilation of the conduit 8 including the connecting housing 5 is performed and liquid is dispensed by the first pump 10. After ventilation of the conduit 8 and the pump, whose speed is adjustable, in a second step 39, the direction of movement (forward / reverse) in which the liquid is to be moved through the conduit 8 is determined. The membrane pumps 10, 19 and the reservoirs 12, 21 allow the liquid to be moved in both directions. The pressure generated by the membrane pumps 10, 19 is set depending on the direction of liquid movement.

[0062] In a third step 40, it is determined whether the pump performance should be manually set. If the pumps are to be manually set, the remainder of the process proceeds via path 40a, and the pressure and / or flow rate of the two pumps are set in step 46. This variant is typically selected when the flush rate, i.e., the flow rate through conduit 8, is small and constant.

[0063] If manual activation is not selected, the next step is taken via arrow 40b, which initiates automatic activation of the pump in a fourth step 41. For this purpose, in step 41 the pressure is first detected by the two pressure sensors 15, 22, from which a pressure difference is calculated in a fifth step 42, from which the activation of the pumps 10, 19 is calculated by corresponding pulses of the control device 11. Here, the determined pressure difference may also be variable over time, e.g., it varies periodically.

[0064] In a sixth step 43, the generated pressure difference is compared with a target pressure difference. If the actual pressure difference corresponds to the target pressure difference, then in a seventh step 44, for example, the pressure difference or flush rate calculated therefrom is displayed accordingly, and the method ends in an eighth step 45. End of the method means that the supply device is in a stable operating state and the pumps 10, 19 are operating and operating accordingly. If in the sixth step 43, it is determined that the actual pressure difference does not correspond to the target pressure difference, then the method returns via path 43a to the fourth step 41, where the pressure difference is measured and from this, an adjustment step is performed to determine a new operation of the pumps.

[0065] Instead of measuring the pressure and adjusting the corresponding pressure difference, the flow rate can also be measured and the corresponding flow rate difference can be set as the control variable.

[0066] Three exemplary variations of typical time courses of flow rate are shown in FIG. 6. Flow rate is plotted as volume per time on the graph's y-axis, with time plotted on the x-axis. A first curve 48 shows the flow rate, measured by, for example, sensor 15 or sensor 22, where the flow rate is constant for most of the time, but the flow rate changes occasionally, e.g., every 20 seconds or every few minutes, with transient increases in flow rate 49, 50. Therefore, no non-flowing flow is formed within conduit 8; such flow leaves certain areas of the conduit untouched, known as stagnation areas, where the liquid there no longer moves. The change in flow rate creates disturbances or flow conditions, which in turn determine stagnation areas and allow liquid to exchange there.

[0067] Another purpose of controlling the flow rate accordingly is to prevent, if possible, particles present in the liquid, for example created by friction of the rotating shaft 2, from moving further so that they are not expelled through the bearing 33 shown in Figure 2 in the area of ​​the blood pump and cannot enter the patient's body.

[0068] If the flow rates detected by the two sensors 15, 22 are plotted on the same graph, a high flow rate can be set so that the flow rate shows a particularly significant difference, for example, particularly in areas 49, 50, which indicates that in these areas 49, 50 some of the liquid is intermittently discharged in very small amounts from the conduit 8 and passes into the inside of the pump housing of the blood pump, thus flushing all of the blood that has accumulated there from the bearing 33.

[0069] In a second variation 51 of the change in flow rate, this varies periodically around a constant course 52, for example in the form of a sinusoid. A constantly varying flow is thus provided, with flow conditions that also constantly vary and ensure liquid exchange in all areas of the conduit 8.

[0070] In a third variation shown in curve 53, besides the temporary periodic increase 54 in the flow rate, the flow direction is also reversed, as shown by way of example in the form of a decrease 55 in the flow rate. The flow reversal changes the direction of the liquid flow in conduit 8, thus also replacing stagnant liquid. Such flow reversals can occur, for example, at intervals of 5 to 10 minutes.

[0071] 7, the measured pressure values ​​are plotted against time t on the y-axis, with a first curve 56 showing the pressure in the region of sensor 15 and a second curve 57 showing the pressure in the region of sensor 22. In two regions 58, 59, the pressure is temporarily increased by first diaphragm pump 10, while the pressure in the return line detected by sensor 22 remains constant. This causes liquid to flow through bearing 33 into the pump housing in regions 58, 59 of increased pressure, thus relieving the pressure in conduit 8.

[0072] As a result of the above-described invention, a delivery device in the form of a flushing device for a hollow catheter for a blood pump is provided, which uses few wearing parts and therefore ensures stable operation with low fluid loss over long periods of time.

[0073] [1] A supply device for supplying a liquid to a conduit (8), comprising at least one membrane pump (10, 19) and a control device (11) for controlling the pump in terms of the pressure generated and / or the delivery rate. [2] 1. The supply device according to claim 1, comprising at least two pumps (10, 19), in particular membrane pumps, arranged at mutually distant points in the conduit (8), and a control device (11) for individually controlling the pumps in terms of the pressure generated and / or the delivery rate. [3] [1] or [2], A supply device characterized in that each pump is assigned a liquid pressure sensor (15, 22). [4] [1], [2] or [3], A supply device characterized in that each pump is assigned an electrical sensor which detects the power consumption, in particular the current consumption, of the pump. [5] [1] to [4], wherein the supply device is A supply device characterized in that each pump is assigned a flow rate sensor (15, 22). [6] 1. A method of operating a dispensing device for dispensing a liquid into a conduit and having a diaphragm-type pump, comprising: A method characterized in that the membrane pump is controlled in terms of the pressure generated and / or the delivery rate. [7] A method for operating a supply device for supplying a liquid to a conduit and having two pumps (10, 19) located at mutually spaced points in the conduit, comprising: Method, characterized in that the parameter values ​​of at least one operating parameter of both pumps (10, 19) are controlled in a mutually coordinated manner. [8] In the method according to [6] or [7], A method in which the liquid pressure is sensed at one point or at a number of different points spaced apart from one another within the conduit. [9] [7] In the method according to The method is characterized in that the adjusted parameter values ​​of the two pumps (10, 19) are variable over time according to a certain scheme, in particular periodically changing for a period after the start-up period.

[10] [7], [8] or [9], A method characterized in that the adjusted parameter values ​​of the two pumps (10, 19) are in a certain ratio to one another that depends in a predetermined way on the detected value of the liquid pressure in the conduit.

[11] [7] -

[10] , A method characterized in that the adjusted operating parameters of both pumps (10, 19) are their respective delivery capacities.

[12] [7] to

[11] , A method characterized in that the adjusted operating parameters of both pumps (10, 19) are the respective values ​​of the liquid pressures generated by the pumps.

[13] [7] -

[12] , A method characterized in that the adjusted operating parameters of both pumps (10, 19) are the respective delivery capacities of the pumps.

[14] [7] -

[13] , A method characterized in that the adjusted operating parameters of both pumps (10, 19) are the respective flow rates of the pumps.

[15] [7] -

[14] , A method characterized in that a constant pressure difference and / or a constant flow rate difference is set between the two pumps (10, 19).

[16]

[15] In the method according to A method characterized in that the difference in flow rate between both pumps (10, 19) is less than 100 milliliters per day, in particular less than 10 milliliters per day, in particular less than 1 milliliter per day.

[17] [6] to

[16] , 10. A method according to claim 1, wherein the pump (10, 19) is controlled so that the direction of movement of the liquid is reversed.

[18] A hollow catheter having a delivery device according to any one of [1] to [5].

[19]

[18] The hollow catheter according to

[18] , comprising a shaft that is rotatable within the hollow catheter.

[20]

[18] or

[19] , wherein the hollow catheter A hollow catheter, characterized in that a flexible shaft is disposed within the hollow catheter. [twenty one] A catheter pump, particularly a catheter pump for intraventricular surgery, including a hollow catheter according to any one of

[18] to

[20] .

Claims

1. 1. A catheter pump comprising: A hollow catheter; a blood pump provided at the distal end of the hollow catheter; The hollow catheter has a supply device for supplying a liquid to a conduit (8) extending between the distal and proximal ends of the hollow catheter; The supply device comprises at least one membrane pump (10, 19), a magnetic device (10a), and a control device (11); The magnetic device (10a) operates the membrane pump (10, 19) by magnetic force; The control device (11) drives the magnetic device (10a) by the generated pulses, The control device (11) adjusts the flow rate and / or pressure generated by the membrane pump (10, 19) according to the frequency and stroke of the pulses; The hollow catheter includes a shaft (2) that is rotatable within the hollow catheter; The rotatable shaft (2) is disposed within the conduit (8), The liquid is used to flush the shaft (2). A catheter pump characterized by:

2. 1. A catheter pump comprising: A hollow catheter; a blood pump provided at the distal end of the hollow catheter; The hollow catheter has a supply device for supplying a liquid to a conduit (8) extending between the distal and proximal ends of the hollow catheter; The supply device comprises at least one membrane pump (10, 19), a connecting housing (5), and a control device (11); The connecting housing (5) is disposed between the conduit (8) and the membrane pump (10, 19) and has a diameter larger than that of the conduit (8); The control device (11) controls the membrane pump (10, 19) in terms of the pressure generated and / or the delivery rate; The hollow catheter includes a shaft (2) that is rotatable within the hollow catheter; The rotatable shaft (2) is disposed within the conduit (8), The liquid is transported into the connecting housing (5) by the membrane pump (10, 19), spreads in the connecting housing (5), travels along the conduit (8) and is used to flush the shaft (2). A catheter pump characterized by:

3. 3. The catheter pump according to claim 1 or 2, the rotatable shaft (2) is flexible; A catheter pump comprising:

4. 4. The catheter pump according to claim 1, the catheter pump is configured for intraventricular surgery; A catheter pump comprising:

5. 5. The catheter pump according to claim 1, the catheter pump is a rotary pump; A catheter pump comprising:

6. 3. The catheter pump of claim 2, the conduit (8) comprises a first conduit region (8a) through which the liquid flows towards the distal end and a second conduit region (8b) through which the liquid flows towards the proximal end; The supply device comprises: a first membrane pump (10) for supplying the liquid to the first conduit region (8a); a second membrane pump (19) for drawing the liquid from the second conduit region (8b); the first membrane pump (10) supplies the liquid to the first conduit region (8a) via the connecting housing (5); the control device (11) controls the first membrane pump (10) and the second membrane pump (19) individually in terms of the pressure generated and / or the pumping rate; A catheter pump characterized by:

7. 7. The catheter pump of claim 6, The direction of movement of the liquid is configured to transport the liquid from the proximal end of the hollow catheter through the first conduit region (8a) to the distal end of the hollow catheter and back to a collection container through the second conduit region (8b). A catheter pump characterized by:

8. 8. The catheter pump according to claim 6 or 7, The first membrane pump (10) and the second membrane pump (19) are controlled so that the direction of movement of the liquid is reversed. A catheter pump characterized by:

9. 9. The catheter pump of claim 8, The direction of movement of the liquid is periodically reversed. A catheter pump characterized by:

10. 9. The catheter pump according to claim 6, wherein: each pump is assigned a liquid pressure sensor (15, 22); A catheter pump comprising:

11. 9. The catheter pump according to claim 6, wherein: Each pump is assigned an electrical sensor that detects the power consumption of that pump, or each pump is assigned a flow rate sensor (15, 22); A catheter pump comprising:

12. 9. The catheter pump according to claim 6, wherein: Each pump is assigned an electrical sensor that detects the current consumption of that pump, or each pump is assigned a flow rate sensor (15, 22); A catheter pump comprising:

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