System for driving a pulsating fluid pump - Patents.com

Abstract

A pulsating fluid pump system for driving a fluid pump assembly includes a reciprocating linear motor having a magnet and a coil, the magnet moving relative to the coil, the coil having an electrical input. The pulsating fluid pump system further includes a controller system having an electrical output coupled to the electrical input of the coil, the controller system configured to execute a waveform program that defines an electrical waveform at the electrical output. The waveform program is configured to control operation of the linear motor by modification of a characteristic selected from the group consisting of amplitude, frequency, shape, and combinations thereof, of the electrical waveform at the electrical output. The waveform program is further configured to accept a set of user-definable parameters that define the performance of the linear motor, and to modify the electrical waveform in response to such parameters.

Description

[Technical field]

[0001] (Related Applications) This application is one of four applications filed on the same day and having Attorney Docket Nos. 4747 / 1001, 4747 / 1002, 4747 / 1003, and 4747 / 1004, each of which is incorporated herein by reference in its entirety.

[0002] (Technical field) The present invention relates to a pulsating fluid pump, and more particularly to a pulsating fluid pump suitable for pumping blood. [Background technology]

[0003] A pulsatile fluid pump is taught in U.S. Patent No. 7,850,593 ("our prior patent") to co-inventors Douglas Vincent and Matthew Murphy. Our prior patent discloses a pump actuated by a linear motor configured to induce reciprocating motion of a flexible membrane, which acts as the wall of a fluid housing, and is in turn coupled to a pair of spherical valves in a manner to implement a pulsatile fluid flow. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 7,850,593 Summary of the Invention [Means for solving the problem]

[0005] According to one embodiment of the present invention, a pulsating fluid pump system for driving a fluid pump assembly includes a reciprocating linear motor having a magnet and a coil, the magnet moving relative to the coil, the coil having an electrical input. The pulsating fluid pump system further includes a controller system having an electrical output coupled to the electrical input of the coil, the controller system configured to execute a waveform program that defines an electrical waveform at the electrical output. The waveform program is configured to control operation of the linear motor by modification of a characteristic selected from the group consisting of amplitude, frequency, shape, and combinations thereof, of the electrical waveform at the electrical output. The waveform program is further configured to accept a set of user-definable parameters that define the performance of the linear motor, and modify the electrical waveform in response to such parameters.

[0006] Alternatively or additionally, the pulsating fluid pump system further includes a graphic display coupled to the controller system, the controller system executing a graphic program configured to cause the graphic display to show a set of user-definable parameters that define the performance of the linear motor.

[0007] Alternatively or in addition, the pulsating fluid pump system further includes a flow sensor mechanically coupled to a fluid path including the integrated pump assembly, the flow sensor having an electrical output coupled to a controller system executing a graphics program configured to cause a graphical display to show a set of items including values ​​of a set of user-definable parameters defining performance of the linear motor and a set of values ​​of physical flow characteristics.

[0008] Alternatively or additionally, the set of items shown includes an instantaneous flow waveform in near real time.Alternatively or additionally, the set of items shown includes an instantaneous ejection volume waveform in near real time.

[0009] Alternatively or additionally, the waveform program is configured to generate an electrical waveform at the electrical output by repeatedly implementing a multi-piece polynomial spline algorithm in a manner responsive to a set of user-definable parameters that define the performance of the linear motor.

[0010] In a related embodiment, the controller system has a storage system in which a prototype electrical waveform is stored, and the waveform program reads the prototype electrical waveform from the storage system and modifies the prototype electrical waveform based on a set of user-definable parameters that define the performance of the linear motor to generate the electrical waveform at the electrical output.

[0011] Alternatively or additionally, the pulsating fluid pump system further includes a set of sensors electrically coupled to the controller system and configured to generate a set of sensor outputs corresponding to the pumping performance, and a waveform program configured to generate an electrical waveform at the electrical output in a manner responsive to the set of sensor outputs and the set of user-definable parameters.

[0012] Alternatively or additionally, a user of the pulsating fluid pump system may select from a set of waveform programs.Alternatively or additionally, the graphic display is touch sensitive. The present invention provides, for example, the following: (Item 1) 1. A pulsating fluid pump system for driving a fluid pump assembly, the pulsating fluid pump system comprising: a reciprocating linear motor having a magnet and a coil, the magnet moving relative to the coil, the coil having an electrical input; a controller system having an electrical output coupled to the electrical input of the coil; Equipped with the controller system is configured to execute a waveform program that defines an electrical waveform at the electrical output; 1. A pulsating fluid pump system, comprising: a first stage for rotating a linear motor in a direction parallel to the first axis of the linear motor; a second stage for rotating a linear motor in a direction parallel to the first axis of the linear motor; a third stage for rotating a linear motor in a direction parallel to the first axis of the linear motor; (Item 2) 2. The pulsating fluid pump system of claim 1, further comprising a graphic display coupled to the controller system, the controller system executing a graphic program configured to cause the graphic display to show a set of user-definable parameters defining a performance of the linear motor. (Item 3) 3. The pulsating fluid pump system of claim 2, further comprising a flow sensor mechanically coupled to a fluid path including the integrated pump assembly, the flow sensor having an electrical output coupled to the controller system, the controller system executing a graphics program configured to cause the graphical display to show a set of items including a set of values ​​of user-definable parameters defining performance of the linear motor and a set of values ​​of physical flow characteristics. (Item 4) 4. The pulsating fluid pump system of item 3, wherein the set of displayed items includes an instantaneous flow waveform in near real time. (Item 5) 4. The pulsatile fluid pump system of item 3, wherein the set of items shown includes an instantaneous ejection volume waveform in near real time. (Item 6) 2. The pulsating fluid pump system of claim 1, wherein the waveform program is configured to generate the electrical waveform at the electrical output by repeatedly implementing a multi-piecewise polynomial spline algorithm in a manner responsive to a set of user-definable parameters that define performance of the linear motor. (Item 7) 2. The pulsating fluid pump system of claim 1, wherein the controller system includes a storage system having a prototype electrical waveform stored therein, and the waveform program reads the prototype electrical waveform from the storage system, modifies the prototype electrical waveform based on a set of user-definable parameters defining performance of the linear motor, and generates the electrical waveform at the electrical output. (Item 8) 2. The pulsating fluid pump system of claim 1, further comprising a set of sensors electrically coupled to the controller system, the set of sensors configured to generate a set of sensor outputs corresponding to pumping performance, and the waveform program configured to generate the electrical waveform at the electrical output in a manner responsive to the set of sensor outputs and a set of user-definable parameters. (Item 9) 2. The pulsating fluid pump system of claim 1, wherein a user of the pulsating fluid pump system can select from a set of waveform programs. (Item 10) 3. The pulsating fluid pump system of claim 2, wherein the graphic display is touch sensitive. [Brief description of the drawings]

[0013] The foregoing features of the embodiments will be more readily understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0014] [Figure 1] FIG. 1 is a vertical cross-section of a pulsating fluid pump system 301 showing a controller system 311, a power amplifier 321, a linear motor 330 (coil 332, cooling fins 334, and magnet 339), a push rod assembly 341, a flexible seal 351, a control housing 361, and an integrated pump assembly 200.

[0015] [Diagram 2] FIG. 2 is an example of a user interface for a touch-sensitive graphic display 400 showing user-definable motor parameters 401 , flow characteristics 411 , and user-definable input parameters 421 .

[0016] [Diagram 3] FIG. 3 is a vertical cross section of push rod assembly 341.

[0017] [Figure 4] FIG. 4 is a vertical cross section of linear motor 330.

[0018] [Diagram 5] FIG. 5 is a block diagram illustrating the waveform program.

[0019] [Figure 6] FIG. 6 is a block diagram illustrating a first embodiment 511 a of the waveform program 511 .

[0020] [Figure 7] FIG. 7 is a block diagram illustrating a second embodiment 511b of the waveform program 511. As shown in FIG.

[0021] [Figure 8] FIG. 8 is a block diagram illustrating the graphics program 611. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Definitions. As used within this description and the accompanying claims, the following terms shall have the meanings indicated, unless the context otherwise requires. A "set" includes at least one member. An "electrical waveform" is a waveform selected from the group consisting of a current waveform, a voltage waveform, and combinations thereof. The term "user-definable input parameters" includes user-definable attributes associated with alert settings or calculations for the user interface, such as lower flow limit 421a, upper flow limit 421b, and body surface area 421c (BSA), and any combination of the aforementioned attributes. The term "user-definable parameters defining the performance of the linear motor" during pumping includes motor performance attributes such as pumping strength 401a, pulsatility rate 401b, flow rate, average flow rate, pumped volume, flow index, pulse pressure, output pressure, magnet displacement, and any combination of the aforementioned attributes. The term "physical flow characteristic" includes measured attributes such as pump strength, pulsatility rate, flow rate, mean flow rate 411a, pump volume 411b, flow index 411c, pulse pressure, flow waveform 412, pump volume waveform 413, the duration the pump is on (e.g., as measured by timer 414), and any combination of the aforementioned attributes. If an attribute is user-defined in a given embodiment of the invention, then the measurement of that attribute is of secondary importance since its value is defined. Similarly, if an attribute being measured is of primary importance in a given embodiment of the invention, then the parameter would not be user-defined.

[0023] FIG. 1 is a vertical cross-section of pulsating fluid pump system 301 showing controller system 311 (with electrical output 311b); power amplifier 321 (with electrical input 321a and electrical output 321b); linear motor 330 (comprising stationary member 331 including coil 332 [with electrical input 332a], frame 333, and cooling fins 334, and moving member including spring 338, and magnet 339 of FIG. 4); position sensor 371; push rod assembly 341 (comprising push rod 342 and force sensor 372); flexible seal 351; control housing 361; and chassis 363. The integrated pump assembly 200 (consisting of the pump valving assembly 101 with chamber 102, the diaphragm assembly 201, and the peripheral flange 221a) is retained within the control housing 361 by the peripheral flange 221a and a compliant member (not shown) within a channel 362 (in these figures, like numbered items correspond to similar components across different figures).

[0024] FIG. 2 is an example of a user interface of a touch-sensitive graphic display 400 showing user-definable motor parameters 401. Appearing in this interface are parameters of stroke strength 401a and stroke rate 401b. These parameters are part of the user-definable parameters that define the performance of the linear motor. In addition, appearing in this interface are flow characteristics 411 (mean flow rate 411a, stroke volume 411b, flow index 411c), flow waveform 412, stroke volume waveform 413, and timer 414. These flow-based attributes are part of the physical flow characteristics. In addition, the user interface displays user-definable inputs 421 (lower flow limit 421a, upper flow limit 421b, and body surface area 421c).

[0025] FIG. 3 is a vertical cross-section of a push rod assembly 341 consisting of a push rod 342 and a force sensor 372 .

[0026] 4 is a vertical cross section of linear motor 330, showing coil 332 with electrical input 332a, frame 333, magnetic centering spring 338, and magnet 339. Other components and details of the motor are provided in FIG.

[0027] In Fig. 5, the waveform program 511 is a computer program executed by the microprocessor 311c of the controller system 311, which accepts inputs from a set of sensors 370 (including the position sensor 371 of Fig. 1, the force sensor 372 of Figs. 1 and 3, and the external flow sensor 373 of Fig. 8), a set of user-definable motor parameters 401 (pump strength 401a and pulsatility rate 401b) that define the performance of the linear motor 330 during the pumping process. In addition, Fig. 5 shows a set of user-definable input parameters 421 (lower flow limit 421a, upper flow limit 421b, and body surface area 421c). The waveform program 511 outputs an electrical waveform 512 (i.e., the result of the set of algorithms 513) at an electrical output 311b. The electrical output 311b is coupled to an electrical input 332a of the linear motor 330.

[0028] There is a growing consensus that the desirable properties of a pulsatile pump should include both sufficient hemodynamic energy and a human-like waveform architecture. To evaluate pulsatile flow, we choose the human heart as the best model, which delivers an appropriate stroke volume in natural rhythm with physiological rest at the end of each stroke and matches the patient's physiological demands by adjusting cardiac output as the product of stroke volume and pulsatility rate. Through the left ventricle, the human heart provides the hemodynamic energy, resulting in a pressure wave that propagates completely through the elastic arterial tree. Only a biomimetic stroke volume delivered in a biomimetic time frame (like the natural systolic contraction generated by the heart) is believed to allow the elastic arterial tree to relax properly during the diastolic phase. The use of continuous flow devices stretches the elastic arterial walls but never allows for proper relaxation, generating constant and abnormal stresses on the endothelium, interfering with the natural baroreceptor sympathetic and parasympathetic signaling, and thus disrupting the body's homeostatic control state.

[0029] The waveform program 511 causes the pulsatile fluid pump system 301 to replicate the ability of the left ventricle of the human heart to deliver physiological hemodynamic energy proportional to the user-defined stroke strength 401a by causing the delivery of a required percentage of the pump chamber 102's stroke volume in a physiological natural rhythm at a user-defined stroke rate 401b. It is the user (perfusionist) of the pulsatile fluid pump system 301 who adjusts the stroke strength 401a (an indirect definition of the stroke volume) and the stroke rate 401b to meet the patient's physiological needs. Furthermore, the waveform program 511 replicates the physiological rest at the end of each stroke, thereby allowing natural relaxation of the arterial tree.

[0030] The structure of the pulsatile pump according to various embodiments of the present invention can usefully reflect the attributes of the human heart. The human heart is preload sensitive, in that it cannot "pull" blood into the left ventricle, but can only allow available blood to flow naturally into the ventricle. The human heart is also afterload sensitive, in that it responds to compliance and resistance in the downstream vasculature and does not exert excessive forces on the blood that could damage the vasculature. Finally, the left ventricle cannot deliver blood that is not present in the ventricle when it contracts, so the bolus of blood it can deliver is limited.

[0031] The pulsating fluid pump system 301 has similar inherent safety attributes: it is preload and afterload sensitive, and the pulsating fluid pump system 301 is limited both in the volume of blood it can deliver and the force with which it can deliver a bolus of blood. When filling, the pulsating fluid pump system 301 allows for gravity filling from an intravenous reservoir, exerting minimal negative pressure. When being emptied, the linear motor 330 is inherently limited by its design in the force it can generate. Thus, it cannot exert undue pressure on the downstream tubing or vasculature; instead, it delivers less than the volume of blood in the pump chamber 102, thereby delivering only as much as the vasculature can receive.

[0032] The integrated pump assembly 200 resembles the left ventricle of the human heart, the inlet spherical check valve assembly used in various embodiments herein resembles the mitral valve, and the outlet spherical check valve assembly used in various embodiments herein resembles the aortic valve. Like the human heart, the inlet and outlet spherical check valve assemblies are passive and require a slight reversal of flow to close. This slight reversal of flow mimics the slight reversal that occurs when the aortic valve of the human heart closes.

[0033] 6, in one embodiment of the present invention, waveform program 511a is a computer program executed by microprocessor 311c of controller system 311, where waveform program 511a accepts inputs from set of sensors 370, set of user definable motor parameters 401, and set of user definable input parameters 421. Waveform program 511a is configured to simulate waveforms that have been experimentally determined to be suitable for an embodiment of pulsating fluid pump system 301 of the present invention. Waveform program 511a simulates the experimentally determined waveforms by repeatedly implementing a multi-piecewise polynomial spline algorithm 513a, and the resulting waveforms are used to drive linear motor 330. When a user changes one of the user-definable motor parameters 401, the waveform program 511a uses the set of user-definable motor parameters 401, zero or more flow characteristics 411, zero or more user-definable input parameters 421, and zero or more of the current and / or previous values ​​from the set of sensors 370 along with the current electrical waveform 512a to generate a new electrical waveform 512b. The waveform program 511a outputs a new electrical waveform 512b consisting of discrete output voltages at predefined durations at the electrical output 311b. The electrical output 311b is coupled to the electrical input 332a of the linear motor 330.

[0034] In another embodiment of the invention, shown in FIG. 7, the waveform program 511b is a computer program executed by the microprocessor 311c of the controller system 311, where the waveform program 511b accepts inputs from the set of sensors 370, the set of user-definable motor parameters 401, and the set of user-definable input parameters 421. The waveform program 511b reads the prototype electrical waveform 512c stored electronically within the controller system 311. The waveform program 511b then uses an algorithm 513b to adjust the prototype electrical waveform 512c. The algorithm 513b uses the set of user-definable motor parameters 401, zero or more flow characteristics 411, zero or more user-definable input parameters 421, and zero or more of the current and / or previous values ​​of the set of sensors 370 along with the current electrical waveform 512a to generate a new electrical waveform 512b from the prototype electrical waveform 512c. The waveform program 511b outputs a new electrical waveform 512b consisting of discrete output voltages of predefined durations at the electrical output 311b, which is coupled to the electrical input 332a of the linear motor 330.

[0035] 8, graphics program 611 is a computer program executed by controller system 311 that accepts user-definable motor parameters 401 and user-definable input parameters 421. Graphics program 611 causes the set of current values ​​of user-definable motor parameters 401, the set of flow characteristics 411, and the set of user-definable input parameters 421 to be shown on a graphics display 400.

[0036] When the pumping intensity 401a value transitions from 0 to a positive value, the graphics program 611 sets the timer 414 to 0 and increments the timer 414 in real time, causing the updated value of the timer 414 to be shown on the graphics display 400 every second. When the pumping intensity 401a value transitions from a positive value to 0, the graphics program 611 stops incrementing the timer 414 and causes the latest value of the timer 414 to be shown on the graphics display 400.

[0037] The graphics program 611 accepts input from the flow sensor 373, calculates the average flow rate 411a, and causes the average flow rate 411a to be shown on the graphics display 400. The graphics program 611 also causes the instantaneous flow rate to be shown on the graphics display 400 as a flow waveform 412 in near real time.

[0038] The graphics program 611 uses data from the flow sensor 373 to calculate the average stroke volume 411b, which is then displayed on the graphics display 400. The graphics program 611 also causes, in near real time, the total volume of fluid currently being delivered for a given stroke to be displayed on the graphics display 400. The volume of fluid currently being delivered for a given stroke is the integral of the instantaneous flow as the stroke volume waveform 413, which is displayed as the shaded area under the flow waveform 412.

[0039] The graphics program 611 accepts input of the body surface area 421c and calculates the flow index 411c as the average flow rate 411a divided by the body surface area 421c. The graphics program 611 causes the body surface area 421c and the calculated flow index 411c to be further shown on the graphics display 400.

[0040] The graphics program 611 accepts input of the lower flow limit 421 a and the upper flow limit 421 b and causes the settings of the lower flow limit 421 a and the upper flow limit 421 b to be shown on the graphics display 400 .

[0041] The embodiments of the invention described above are intended to be merely exemplary, and numerous variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present invention, as defined in any appended claims.

Claims

1. 1. A pulsating fluid pump system for driving a fluid pump assembly, the pulsating fluid pump system comprising: a reciprocating linear motor having a magnet and a coil, the magnet moving relative to the coil, the coil having an electrical input; a controller system having an electrical output coupled to the electrical input of the coil and a memory system in which a prototype electrical waveform is stored; Equipped with the controller system is configured to execute a waveform program that defines an electrical waveform at the electrical output; 1. A pulsating fluid pump system comprising: a first stage for generating an electrical waveform at an electrical output, the first stage comprising: a first stage for generating an electrical waveform at an electrical output by reading a prototype electrical waveform from the storage system in response to the user-provided values ​​for such parameters; and a second stage for generating an electrical waveform at an electrical output by modifying the prototype electrical waveform with respect to characteristics selected from the group consisting of amplitude, frequency, shape, and combinations thereof.

2. The pulsating fluid pump system of claim 1, further comprising a graphic display coupled to the controller system, the controller system executing a graphic program configured to cause the graphic display to show a set of user-definable parameters defining performance of the linear motor.

3. The pulsating fluid pump system of claim 2, further comprising a flow sensor mechanically coupled to a fluid path including an integrated pump assembly, the flow sensor having an electrical output coupled to the controller system, the controller system executing a graphics program configured to cause the graphic display to show a set of items including a set of values ​​of user-definable parameters defining performance of the linear motor and a set of values ​​of physical flow characteristics.

4. The pulsating fluid pump system of claim 3 , wherein the set of represented items includes a near real-time instantaneous flow waveform.

5. The pulsatile fluid pump system of claim 3 , wherein the set of displayed items includes a near real-time instantaneous stroke volume waveform.

6. 2. The pulsating fluid pump system of claim 1, wherein the waveform program is configured to generate the electrical waveform at the electrical output by iteratively executing a multi-piecewise polynomial spline algorithm in a manner responsive to a set of user-definable parameters defining performance of the linear motor.

7. The pulsating fluid pump system of claim 1, further comprising a set of sensors electrically coupled to the controller system, the set of sensors configured to generate a set of sensor outputs corresponding to pumping performance, and the waveform program configured to generate the electrical waveform at the electrical output in a manner responsive to the set of sensor outputs and a set of user-definable parameters.

8. 10. The pulsating fluid pumping system of claim 1, wherein a user of the pulsating fluid pumping system can select from a set of waveform programs.

9. 3. The pulsating fluid pump system of claim 2, wherein said graphic display is touch sensitive.

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