Pressure sensor arrangement and method

Abstract

The invention relates to a pressure sensor (100) comprising a biocompatible housing (110), a biocompatible flexible membrane (120) covering an open portion in the housing (110), a pressure transmitting medium, an attachment portion (130), an electrical connection (140) and a pressure sensitive sensor (150).

Description

Technical Field

[0001] In general, the present invention relates to a pressure sensor arrangement suitable for use in cardiac prostheses (total artificial hearts), heart assist pumps (ventricular assist devices: VAD, LVAD, etc.) or as an implant for measuring venous and arterial pressure in the pulmonary or systemic circulation. Background Art

[0002] The same applicant discloses a blood pumping device or an artificial heart in, for example, WO 2016 / 020219 or WO 2017 / 137486.

[0003] Other blood pumps are known, for example, from US 2003045772 and US 20190351118.

[0004] Despite steady progress in developing permanent artificial hearts for long-term implantation in patients to replace failing natural hearts, several challenges remain. These include control strategies for responding to varying physiological demands and mechanisms for regulating flow imbalances between the pulmonary and systemic circulations in untethered artificial heart systems.

[0005] Differences in left-right cardiac output are well documented. Physiologically, the left side of the heart pumps a higher volume of blood than the right side. This difference is primarily due to a circulatory pathway known as bronchial shunt. This flow originates in the left arterial system, passes through the bronchial tissue, and then returns directly to the left atrium. This difference, with left-side flow always greater than right-side flow, typically manifests as up to approximately ten percent of cardiac output. Artificial heart systems must account for this inherent physiological circulatory imbalance. Furthermore, sources of flow imbalance can be engineered. For example, flow imbalance can be introduced by differential regurgitation through prosthetic valves placed on the left and right sides. Artificial heart systems must also account for these types of circulatory imbalances. Summary of the Invention

[0006] A pressure sensor is needed that allows pressure, in particular blood pressure, to be measured on or in communication with a cardiac prosthesis, a total artificial heart (TAH), a cardiac assist pump (e.g., a ventricular assist device (VAD), a LVAD, etc.), or as an implant for measuring venous and arterial pressure in the pulmonary and systemic circulations. The invention also relates to a controller that can automatically control parameters, such as the stroke rate and stroke volume of a blood pump, based on the pressure values ​​obtained from the pressure sensor.

[0007] For these reasons, a pressure sensor is provided, comprising a biocompatible shell, a biocompatible flexible membrane covering an opening in the shell, a pressure transmitting medium, an attachment portion, an electrical connection, and a pressure sensitive sensor. The sensor housing can be made of hard polyurethane, hard organosilicon, biocompatible metal (such as titanium or stainless steel) or any other biocompatible rigid material. The attachment portion can be made of biocompatible materials, such as Dacron, expanded polytetrafluoroethylene (ePTFE), polyester or other materials that can heal together with natural tissue. The pressure sensitive sensor can include a small microelectromechanical system (MEMS) sensor or a nanoelectromechanical system (NEMS). The flexible membrane can be made of polyurethane, titanium, organosilicon or any other blood compatible material. The pressure transmitting medium in the shell can be made of biocompatible, implantable oil (such as medical grade organosilicon oil). The sensor is intended for use on, or in communication with, one or more of a cardiac prosthesis, a total artificial heart, a heart assist pump, as an implant for measuring venous and arterial pressure in the pulmonary and systemic circulations, for thoracic pressure measurement, and for renal, bladder, or intra-abdominal pressure measurement.

[0008] The present invention also relates to a controller unit for controlling a cardiac prosthesis, the prosthesis comprising: at least one pump section; an inlet connected to the at least one pump section; an outlet connected to the at least one pump section; a pressure sensor configured to measure the pressure of a fluid flowing from the inlet to the outlet; a pump actuator configured to induce the flow of the fluid, wherein the controller unit further comprises a memory and a processing unit. The controller unit is configured to: obtain a pressure value from the pressure sensor, obtain a desired value for the pressure of the fluid flowing into the pump, calculate an error signal equal to the difference between the desired pressure value and the measured pressure, and control the output of the pump by controlling the pump stroke rate and / or pump stroke volume so that the measured pressure approaches or equals the desired pressure.

[0009] The present invention also relates to a cardiac prosthesis comprising the pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Referring to the drawings, elements having the same reference numbers may represent similar elements throughout.

[0011] Figure 1 is a schematic perspective view of a pressure sensor according to an exemplary embodiment.

[0012] Figure 2 yes Figure 1 Schematic cross-sectional view of a pressure sensor.

[0013] Figure 3 This is a first exemplary application embodiment of the pressure sensor according to the present invention.

[0014] Figure 4 This is a second exemplary application embodiment of the pressure sensor according to the present invention.

[0015] Figure 5 and Figure 6 A third exemplary application embodiment of the pressure sensor according to the present invention is shown.

[0016] Figure 7a and Figure 7b A fourth exemplary application embodiment of the pressure sensor according to the present invention is shown.

[0017] Figure 8 is a schematic diagram of a controller according to an aspect of the present invention.

[0018] Figure 9 is a schematic diagram of a control unit according to the present invention.

[0019] Figure 10 is a schematic diagram of a controller unit according to the present invention. DETAILED DESCRIPTION

[0020] The following detailed description refers to the accompanying drawings.

[0021] The term artificial heart as used herein may relate to a pumping device connectable to a subject.

[0022] Figure 1 A pressure sensor 100 according to an exemplary embodiment of the present invention is shown below. The pressure sensor comprises a substantially dome-shaped housing 110, a pressure-sensitive elastic membrane 120, an attachment ring 130 and electrical connections 140.

[0023] Pressure sensor 100 Figure 2 Detailed description is given in the cross-sectional view.

[0024] The pressure-sensitive sensor 150 is arranged on a circuit board 160 , which also carries electronic components 162 and connections to the electrical connections 140 .

[0025] The inner surface of the housing 110 includes a base 111, which includes screw holes for receiving screws 112. The circuit board is attached to the inner surface of the housing 110 by means of screws 112. Obviously, other connection methods, such as adhesives, can also be used to connect the circuit board to the housing.

[0026] The guide tube 163 may be disposed on one surface of the circuit board. The lumen of the guide tube communicates with the surface of the pressure sensitive sensor 150. However, in some exemplary embodiments, the guide tube may not be included.

[0027] The space 170 within the housing is completely filled with the pressure transmitting medium.

[0028] The sensor housing 110 may be made of rigid polyurethane, rigid silicone, a biocompatible metal (such as titanium or stainless steel), or any other biocompatible rigid material.

[0029] The attachment ring 130, which fully or partially surrounds the lower portion of the housing, may be made of Dacron, ePTFE, polyester, or other materials that will heal with natural tissue.

[0030] The pressure sensitive sensor 150 may include a miniature micro-electromechanical system (MEMS) sensor, a nano-electromechanical system (NEMS), or any other suitable pressure sensor architecture.

[0031] The flexible membrane 120 is sealed in a leak-proof manner, for example, using an adhesive or a sealing gasket, to the housing 110 and can be made of polyurethane, silicone, titanium or any other blood-compatible material. Thus, the sensor body is fully sealed.

[0032] The pressure transmitting medium or agent filled in the space 170 of the housing 110 may be composed of a biocompatible, implantable oil, such as medical-grade silicone oil, or any other biocompatible, medical-grade fluid.

[0033] During operation, when membrane 120 is subjected to pressure (e.g., blood pressure), the flexible membrane 120 bulges when the pressure on the membrane increases, or bends outward when the pressure decreases. As a result, the pressure-transmitting medium within the housing is compressed or expanded due to the pressure acting on the flexible membrane 120. The pressure is transmitted from the membrane to the surface of sensor 150 via the pressure-transmitting medium within guide tube 163 (if present). Thus, the sensitive surface of the MEMS sensor is affected by the pressure changes in the pressure-transmitting medium. The MEMS sensor converts the pressure into a digital value, generating an electrical signal representing the pressure that can be provided to a controller.

[0034] The pressure sensor described and illustrated is provided as an example. The housing and form of the sensor can be varied in various ways depending on the application. The sensor components, electronics, and connections can also vary depending on the application. Wireless transmission capabilities may also be included.

[0035] Figure 3A first example of an application of the previously described pressure sensor is shown. In this case, a subject's heart 300 is configured with a left ventricular assist device (LVAD). The LVAD includes a pump 310 and connecting conduits 311 and 312. Pump 310 pumps blood to the body and is a battery-powered mechanical device that is surgically implanted in the subject's chest. The LVAD helps maintain the pumping ability of a heart that is too weak to work on its own. The device supports the main pumping chamber, the left ventricle, by transporting blood to the aorta and other parts of the body. The pump 310 is connected to the left ventricle by conduit 311 and to the aorta by conduit 312. The sensor 100 is arranged on conduits 311 and 312 at the inlet and outlet of the pump 310. The conduit includes a flexible membrane 120 ( Figure 2 ). The sensor's base is attached to the catheter and covers the window, exposing the flexible membrane to the blood pressure in the catheter. Pressure sensor 100 is connected to a controller unit 1000, either inside or outside the subject's body, via a connecting line 140.

[0036] Figure 4 A second example of the application of the previously described pressure sensor is shown. A subject's heart 300 is configured with a pressure sensor 100. In this example, the pressure sensor 100 is attached to (from the top of the figure) the aorta, pulmonary artery, right atrium, left atrium, right ventricle, and left ventricle. These locations are given as examples, and the pressure sensor can be placed at any location where a pressure value is required. The pressure sensor can be attached to the heart tissue myocardium through Dacron, ePTFE, polyester, or to the epicardium. The pressure sensor in this example can be connected to a cardiac prosthesis, such as a TAH or VAD system, to regulate the flow in the device according to the blood pressure value in one / more chambers of the heart 300.

[0037] Figure 5 and Figure 6 A third application is shown. Figure 5 A portion of the chest cavity 500 is shown. Figure 6 It is along Figure 5 Schematic diagram of a cross section of the tissue, taken along line AA.

[0038] Reference numeral 501 denotes ribs, 502 skin, 503 superficial fascia, 504 intercostal muscles, 505 parietal pleura, 506 pleural cavity, 507 visceral pleura, and 508 lungs.

[0039] In this application, the pressure sensor 100 is placed between the ribs 501 and in the intercostal muscles 504. Electrical connections are not shown, but may extend outward through the tissue. The pressure sensor may also be placed near the costal cartilage.

[0040] In TAH applications or heart assist pump applications, it may be important to measure the pressure in the thoracic cavity. During breathing, the pressure in the thoracic cavity changes continuously. Since the pressure in the thoracic cavity affects the pressure in the atria, it is best to also measure the pressure in the thoracic cavity (reference pressure). This makes it possible to compensate for changes in the pressure in the thoracic cavity. The pressure in the thoracic cavity can be measured in the following ways:

[0041] 1. Use a pressure sensor that is built into the pump but is designed to measure intrathoracic pressure,

[0042] 2. Use a separate pressure sensor placed in the chest cavity and connected to the pump by wires, or

[0043] 3. Place the pressure sensor outside the chest cavity but inside the chest wall, and just in contact with the parietal pleura layer 505 in the above example.

[0044] Thus, the pressure sensor 100 can be connected to the pleura (pleural membrane), which will act as a naturally flexible membrane between the chest cavity and the pressure sensor. It may be sufficient to use a single pressure sensor for both the right and left pumps to measure intrathoracic pressure, eliminating any effects of breathing and measuring externally to the heart itself. The control unit can receive input signals from the pressure sensor and output signals to the pump drive system. These signals can be received and provided directly via electrical wiring.

[0045] The pressure sensor of the present invention can be implanted in other body cavities or organs, such as the kidney, bladder, abdominal cavity, etc., where pressure readings are required, or be connected thereto.

[0046] Figure 7a and Figure 7b A fourth exemplary application of the aforementioned pressure sensor is shown. Figure 7a A perspective view of a pump 700, a pump section of a TAH, is shown. Figure 7b is a cross-sectional view of the pump 700 .

[0047] This embodiment includes a first blood receiving part 700 of the artificial heart and a drive / actuation system 750, which is used to drive / actuate the artificial heart to produce a pumping mechanism. The artificial heart mainly consists of two pumps 700, namely a left pump and a right pump (not shown). Each pump includes a blood receiving part and a drive / actuation system. The blood receiving part is simply assembled to the drive system by screws, glue or a combination thereof. The blood receiving part includes an artificial atrium 709 and an artificial ventricle 712. There is a connecting cylinder 720 between the artificial atrium 709 and the artificial ventricle 712, which is a valve corresponding to the mitral valve on the left side of the natural heart and the tricuspid valve on the right side of the natural heart. The connecting cylinder can be made of a flexible blood-compatible material, such as polyurethane, silicone or any other blood-compatible material.

[0048] Each atrium 709 is primarily composed of an atrial covering wall, which is primarily composed of two layers. The outer layer 7091 is rigid and made of hard polyurethane, hard silicone, a biocompatible metal such as titanium or stainless steel, or any other biocompatible hard material. Furthermore, there is an inner flexible blood-compatible membrane 7092 made of polyurethane, silicone, or any other blood-compatible material. The inner flexible membrane is an extension of the flexible atrial membrane, which is an extension of flexible membrane 7093. This flexible membrane 7093 lines the inner surface of the connecting atrioventricular cylinder (AV-cylinder) 720, which is an extension of the flexible ventricular membrane 7121. Furthermore, there is an atrial mounting ring 721, which is rigid and made of rigid polyurethane, rigid silicone, a biocompatible metal such as titanium or stainless steel, or any other biocompatible rigid material. The atrial mounting ring is assembled to the upper edge of the drive / actuation system using screws, glue, or a combination thereof. The atrium has an inlet opening 710 to allow blood to flow within the atrium. There is a pressure window 7641 having a diameter of, for example, at least 5-30 mm, which may be circular, oval, or any other shape. The pressure window wall consists solely of a flexible membrane, with no rigid wall layer. As previously mentioned, this pressure window is part of the structure of pressure sensor 100.

[0049] Each ventricle 712 is mainly composed of a ventricular covering wall, which is mainly composed of two layers, the outer layer is rigid and made of rigid polyurethane, rigid silicone, biocompatible metal such as titanium or stainless steel, or any other biocompatible rigid material. Further, there is an inner layer flexible blood compatible membrane 7121 made of polyurethane, silicone, or any other blood compatible material. The inner layer flexible membrane is an extension of the flexible ventricular membrane, which is an extension of the flexible membrane 7093, which lines the inner surface of the atrio-ventricular-cylinder 720. Further, there is a ventricular fitting ring 722, which is rigid and made of rigid polyurethane, rigid silicone, biocompatible metal such as titanium or stainless steel, or any other biocompatible rigid material. The ventricular fitting ring is fitted to the lower edge of the drive / actuation system by screws, glue, or a combination thereof.

[0050] The drive / actuation system 750 comprises a housing 762, a gear box 753, and a motor 751. The housing is made of hard plastic biocompatible material, such as polyether ether ketone (PEEK), and any other biocompatible plastic material or biocompatible metal. The housing encloses the gear box and the motor. The gear box is composed of a number of gears and metal shafts. The motor is of the brushless motor type or any other type of motor with or without an encoder. The pressure sensor will be described in detail later in this application. The motor 751 is arranged between the outlet 713 and the pump and inside the pump housing. A gasket 760 can be provided between the housing outlet 713 and the motor 751. The gasket 760 is made of a material with good heat conduction capacity so that when blood (or other liquid) flows through the outlet tube 700, heat from the drive mechanism is transferred through the gasket 760 and the wall of the outlet 713 into the blood, thereby transferring and reducing heat from the drive mechanism.

[0051] The center of the drive / actuation system has a cylindrical shape and encloses the atrio-ventricular-cylinder 720, which is made of rigid plastic biocompatible material, such as rigid polyurethane, rigid silicone, or biocompatible metal, such as titanium, stainless steel, or any other biocompatible rigid material. The atrio-ventricular-cylinder is lined by the flexible membrane 7093, which is an extension of the flexible atrial membrane 7092 and the flexible ventricular membrane 7121. The atrio-ventricular-cylinder encloses the valve 714. There are two racks, 725 and 726, one on each side of the atrio-ventricular-cylinder 720. Each rack is articulated with the gears of the gear box 753 so as to be actuated in the upward and downward directions.

[0052] There may be wires (not shown) connected to the drive / actuator system to provide power and control signals to the motor. In addition, there may be a cover film (not shown), which is a layer of biocompatible plastic material, such as polyurethane or silicone, surrounding the entire driver / actuator system, allowing the wires connected to the motor and the catheter for the pressure sensor to pass through the cover film.

[0053] The sensor 100 structure includes an opening 7641 in the wall of the chamber 709, through which the flexible membrane 120 is exposed to the pressure from the chamber 709. Thus, as previously described, the pressure sensor pressure receiving portion is arranged in the left (or right) atrium 709 and the right pump atrium (or the upper half of each pump). The flexible membrane 120 is arranged as part of the inner wall of the housing.

[0054] During operation, when the membrane 120 of the atrial wall 760 is affected by the blood pressure within the atrium 709 of each pump, the flexible membrane 120 bulges toward the interior of the pressure sensor 100 when the pressure within the atrium increases, or bends toward the atrial cavity when the pressure decreases. Thus, the pressure-transmitting medium within the housing and the lumen of the tube 163 compresses or expands due to the pressure within the atrium 709. The pressure is transmitted from the membrane within the tube 163 to the surface of the sensor 734. Thus, the sensitive surface of the MEMS sensor 150 is affected by the pressure changes in the pressure-transmitting medium, and the MEMS sensor converts the pressure into a digital value, generating an electrical signal representing the pressure and providing it to the controller unit.

[0055] Many of the previously described embodiments involve pulsating or positive displacement pumps; however, the methods, sensors, and control units of the present invention are equally applicable to systems with different types of pumps, such as centrifugal pumps or other continuous flow pumps. Continuous flow pumps may include one or more of the following types: canister pumps, radial pumps, side channel pumps, regenerative turbine pumps, axial pumps, and diagonal pumps. Positive displacement pumps may include one or more of the following types: metering pumps, progressive cavity pumps, gear pumps, multi-screw pumps, piston diaphragm pumps, plunger and piston pumps, rotary lobe pumps, vacuum pumps, and hose pumps.

[0056] Thus, the term "stroke volume" as used herein relates to a specific amount of fluid displaced in a specific time interval, and the term "heart rate" as used herein relates to the rate at which a pump displaces a certain amount of fluid.

[0057] As used herein, the terms right atrium or left atrium refer to the compartment within the pump housing into which fluid is supplied and from which fluid is discharged.

[0058] Figure 8 FIG2 illustrates a schematic diagram and functional blocks of an exemplary control unit 800 for TAH applications. According to this embodiment, the control unit 800 may include functional blocks:

[0059] - right heart output control 801 for the right atrium,

[0060] - left heart output control 802 for the left atrium,

[0061] - flow control block 803, and

[0062] - processing block 804.

[0063] The main function of the control unit 800 is to set the heart rate and stroke volume of either half of the blood pump 700 (i.e. the left and right pumps) to values that are appropriate for the current physiological state of the subject.

[0064] The control problem can be solved by breaking it down into sub-problems, including:

[0065] - flow control: this determines the correct flow limit and the desired atrial pressure, which will be used as input to keep the cardiac output within the appropriate range. The desired atrial pressure can be overridden by allowing the operator of the prosthesis to manually set the desired atrial pressure.

[0066] - determining the cardiac output of either pump to control the atrial pressure: this is done separately, with no interdependence between the pumps.

[0067] - determining the heart rate: the heart rate and cardiac output of either pump (calculated in the previous step) will in turn provide the stroke volume of either pump.

[0068] The inputs to the functional blocks include:

[0069] - the right atrial pressure (RAP), measured by a pressure sensor 100 in the right atrium, to the (right) heart output control 801; and

[0070] - the left atrial pressure (LAP), measured by a pressure sensor 100 in the left atrium, to the (left) heart output control 802.

[0071] Determining the cardiac output of either pump can be done with only the atrial pressure as input.

[0072] As mentioned above, the stroke volume can be calculated as the stroke length multiplied by a constant, and therefore can not be in agreement with the actual pumped stroke volume. This means that the reported flow is also only an approximation.

[0073] The functional block flow control 803 determines the flow limit and the desired atrial pressure. The flow limit is the boundary for the cardiac output of the right pump.

[0074] The goal of flow control is to keep the flow of the right pump 802 low enough so that the left pump 803 never reaches its maximum flow. If this happens, i.e., maximum flow is reached, the left pump cannot keep the left atrial pressure (LAP) within boundaries, which will bring the risk of pulmonary edema. Limiting the capacity of the right pump may cause the right atrial pressure (RAP) to increase; however, this can be considered acceptable. A higher right atrial pressure (RAP) will also increase the central venous pressure (CVP), which will help to reduce venous return. The flow control block 803 receives the output from the left cardiac output control 802 and sets the limits for the desired right atrial pressure (Desired RAP), the desired left atrial pressure (Desired LAP), and the right cardiac output.

[0075] Even given the same heart rate and stroke length, the actual flow rate of either half of the pump 700 may depend on various factors, such as outflow pressure and inflow pressure. Therefore, the flow limit of the right pump (700) cannot be set to a constant, but must be changed dynamically.

[0076] The controller unit 800 can be an implanted or integrated microcomputer or electronic chip. The microcomputer can provide control signals to the pump actuator to change its pumping activity. If for some reason the microcomputer does not receive any input information, the pump actuator can continue to maintain a constant activity level. Figure 9 FIG. 9 is a block diagram of another exemplary controller unit 900, for example, for cardiac assist pump (VAD, LVAD, etc.) applications. According to this embodiment, the controller unit 900 may include functional blocks:

[0077] - Cardiac output control 901, and

[0078] -Process block 904.

[0079] The main function of the control unit 900 may be to set the speed of the blood pump 310 to a value suitable for the current physiological state of the subject.

[0080] Although according to Figure 8 The controller unit 800 of the embodiment can be applied to a pulsating pump, but Figure 9 The controller unit 900 may be adapted for use with a continuous flow pump. However, the controller unit 800 may also be configured to set the pulsation speed and thereby the pump speed.

[0081] Figure 101 is a diagram of an exemplary controller unit 1000 in which the methods described herein may be performed. The controller unit 1000 may include a bus 1010, a processor 1020, a memory 1030, a read-only memory (ROM) 1040, a storage device 1050, an input device 1060, an output device 1070, and a communication interface 1080. The bus 1010 allows communication between the components of the controller unit 1000. The controller unit 1000 may also include one or more power supplies (not shown). Those skilled in the art will recognize that the controller unit 1000 may be configured in a variety of other ways and may include other or different elements.

[0082] Processor 1020 may include any type of processor or microprocessor that interprets and executes instructions. Processor 1020 may also include logic capable of decoding media files and generating output to, for example, speakers, a display, etc. Memory 1030 may include random access memory (RAM) or another dynamic storage device that stores information and instructions executed by processor 1020. Memory 1030 may also be used to store temporary variables or other intermediate information during the execution of instructions by processor 1020.

[0083] ROM 1040 may include a conventional ROM device and / or another static storage device that stores static information and instructions for processor 1020. Storage device 1050 may include a magnetic disk, a solid-state drive, or an optical disk and its corresponding drive and / or some other type of recording medium and its corresponding drive for storing information and instructions. Storage device 1050 may also include a flash memory (e.g., an electrically erasable programmable read-only memory (EEPROM)) device for storing information and instructions.

[0084] The input device 1060 may include one or more conventional mechanisms for allowing a user to input information to the controller unit 1000, such as a keyboard, a keypad, arrow keys, a mouse, a pen, voice recognition, a touch screen, and / or a biometric recognition mechanism. The output device 1070 may include one or more conventional mechanisms for outputting information to the user, including a display, a printer, one or more speakers, and the like. The communication interface 1080 may include any transceiver-like mechanism that enables the controller unit 1000 to communicate with other devices and / or systems. For example, the communication interface 1080 may include a modem or an Ethernet interface to a local area network (LAN). Alternatively or additionally, the communication interface 1080 may include other mechanisms for communicating via a network (e.g., a wireless network). For example, the communication interface may include a radio frequency (RF) transmitter and receiver and one or more antennas for transmitting and receiving radio frequency data.

[0085] Controller unit 1000, consistent with the present invention, as previously described, provides a platform. According to an exemplary embodiment, controller unit 1000 can perform various processes in response to processor 1020 executing a sequence of instructions contained in memory 1030. Such instructions can be read into memory 1030 from another computer-readable medium, such as storage device 1050, or from a separate device via communication interface 1080. It should be understood that a computer-readable medium may include one or more storage devices or carrier waves. Execution of the sequence of instructions contained in memory 1030 causes processor 1020 to perform the actions described above. In alternative embodiments, hard-wired circuitry can be used in place of or in combination with software instructions to implement aspects consistent with the present invention. Therefore, the present invention is not limited to any specific combination of hardware circuitry and software.

[0086] It should be noted that the word "comprising" does not exclude the presence of other elements or steps than those listed, and the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. It should be further noted that any figure signs do not limit the scope of the claims, the present invention may be implemented at least in part by hardware and software, and several "means", "units" or "devices" may be represented by the same hardware.

[0087] The embodiments mentioned and described above are given as examples only and should not be considered as limitations of the present invention. For those skilled in the art, other solutions, uses, purposes and functions within the scope of the present invention as claimed in the patent claims described below should be obvious.

[0088] The various embodiments of the present invention described herein are described in the general context of method steps or processes, which can be implemented in one embodiment by a computer program product embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by a computer in a network environment. Computer-readable media may include removable and non-removable storage devices, including but not limited to read-only memory (ROM), random access memory (RAM), compact discs (CDs), digital versatile discs (DVDs), solid-state drives, and the like. Generally, program modules may include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing the steps of the methods disclosed herein. A particular sequence of such executable instructions or associated data structures represents an example of corresponding actions for implementing the functions described in those steps or processes.

[0089] Software and web implementations of various embodiments of the present invention can be accomplished using standard programming techniques with rule-based logic and other logic to accomplish the various database search steps or processes, association steps or processes, comparison steps or processes, and decision steps or processes. It should be noted that the terms "component" and "module," if used herein and in the appended claims, are intended to encompass implementations using one or more lines of software code, and / or hardware implementations, and / or implementations of devices for receiving manual input.

[0090] The foregoing description of the embodiments of the present invention has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the embodiments of the invention to the precise form disclosed, and modifications and variations may be made in light of the foregoing teachings or may be derived from the practice of the various embodiments of the invention. The embodiments discussed herein have been selected and described in order to explain the principles and properties of the various embodiments of the invention and their practical application to enable those skilled in the art to utilize the invention in its various embodiments and with various modifications suitable for the particular use under consideration. The features of the embodiments described herein may be combined in all possible combinations in methods, apparatus, modules, systems, and computer program products.

Claims

1. A pressure sensor (100), comprising: - a housing (110) having an opening portion, - a flexible film (120) covering the opening portion of the housing (110), a space (170) formed by the housing and the flexible membrane, wherein the space is configured to be completely filled with a pressure-transmitting medium; It is characterized in that - the housing (110) further comprising an attachment ring (130) surrounding the opening portion of the housing and the flexible membrane and configured to attach the pressure sensor to a surface of an object, a pressure-sensitive sensor (150) attached to the inner surface of the housing via a circuit board (160) and having a surface for receiving pressure transmitted from the flexible membrane and the pressure transmission medium, - the housing and the attachment ring are made of a biocompatible material, and the flexible membrane is made of a biocompatible flexible material; and - an electrical connection line (140) configured to connect the pressure-sensitive sensor to the controller unit (1000).

2. The sensor according to claim 1, wherein The sensor housing (110) is made of one of hard polyurethane, hard silicone, biocompatible metal including titanium or stainless steel, or any other biocompatible rigid material.

3. The sensor according to claim 1, wherein The attachment ring (130) is made of a biocompatible material including Dacron, ePTFE, polyester or other materials that can heal with natural tissue.

4. The sensor according to claim 1, wherein The pressure sensitive sensor (150) comprises a small micro-electromechanical system (MEMS) sensor or a nano-electromechanical system (NEMS) sensor.

5. The sensor according to claim 1, wherein The flexible membrane (120) is made of polyurethane, silicone or any other blood-compatible material.

6. The sensor according to claim 1, wherein The pressure transmitting medium in the housing is composed of a biocompatible medical fluid, including a biocompatible, implantable oil, or a medical grade silicone oil.

7. The sensor according to claim 1 is used in one or more of a cardiac prosthesis, a total artificial heart, or a heart assist pump, or is connected thereto, as an implant for measuring venous pressure, atrial pressure, or arterial pressure in the pulmonary circulation and systemic circulation, chest pressure, or kidney, bladder, or intestinal pressure.

8. A controller unit (800, 900, 1000) for controlling a heart pump, the heart pump comprising: at least one pump section (700, 310), an inlet (710) connected to the at least one pump section, an outlet (713) connected to the at least one pump section, The pressure sensor (100) according to any one of claims 1 to 7, configured to measure the pressure of a fluid flowing from an inlet to an outlet, a pump actuator (750) configured to cause the flow of a fluid stream, and The controller unit further comprises a memory (1030) and a processing unit (1020), wherein the processing unit is configured to: - receiving a pressure value from said pressure sensor, - receiving a desired value for the pressure of the fluid flowing into said pump, - calculating an error signal, said error signal being equal to the difference between said expected value of said pressure and said measured pressure, and - controlling the output of the pump by controlling pump control parameters such that the measured pressure approaches or is equal to the desired pressure, the pump control parameters comprising one or more of pump stroke rate and / or pump stroke volume and / or pump speed.

9. A cardiac prosthesis comprising the pressure sensor according to any one of claims 1 to 7.

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