Method and apparatus for detecting a state of wear in a cardiac assist system and for operating the same, and cardiac assist system - Patents.com

Abstract

The present invention relates to a method for detecting a state of wear in a cardiac assist system, the method comprising a reading step and a determining step. During the reading step, a sensor signal (315) representative of an operating state of the cardiac assist system is read. During the determining step, a wear signal (325) is determined using the sensor signal (315) and a comparison rule (320). The wear signal (325) is representative of the state of wear. [Selected figure] Figure 3

Description

[Technical field]

[0001] The present invention relates to an apparatus or a method of the type described in the independent patent claims. [Background technology]

[0002] No. 5,904,708 describes a system having an implanted air pressure sensor, an external air pressure sensor, and an implanted processing unit that receives and processes the external pressure to detect blood pressure changes, allowing data from the implanted pressure sensor and the external pressure sensor to be used to set or control functions of an implantable medical device.

[0003] On this basis, the objective underlying the present invention is to further improve methods and devices known in the state of the art for operating, and in particular for monitoring, not only the state of the cardiac assist system but also the cardiac assist system itself, and to ensure high functional reliability and ideally avoid serious system failures.

[0004] With this in mind, the approach presented herein introduces a method for detecting a state of wear in a cardiac assist system, a method for operating a cardiac assist system as well as an apparatus for using and / or controlling said method and cardiac assist system in accordance with the main claims. Advantageous further developments and improvements of the apparatus specified in the independent patent claims are possible using the measures specified in the dependent claims.

[0005] Using the approach presented herein, a sensor signal representative of an operating condition of the cardiac assist system can be read and processed. The operating condition can be, for example, a physical condition of the cardiac assist system or a condition of the environment in which the cardiac assist system is operating. Using the sensor signal and the processing specifications, a wear signal representative of a state of wear of the cardiac assist system can be determined, for example, by comparing the sensor signal with a particular operating condition of the cardiac assist system. This advantageously allows for a continuous monitoring of the state of the cardiac assist system, for example, to detect damage or aging of the cardiac assist system or a wearing process of the cardiac assist system. This is useful for enabling to avoid failure of the cardiac assist system or to enable rapid action to be taken in case of such a wearing condition. By monitoring the condition and detecting a wearing condition, the safety and reliability of the cardiac assist system can be advantageously improved. Summary of the Invention

[0006] The present invention provides a method for detecting a state of wear of a cardiac assist system, the method comprising a reading step and a determining step, in which a sensor signal representative of an operating state of the cardiac assist system is read, and in which a wear signal is determined using the sensor signal and a comparison rule, the wear signal being representative of the state of wear.

[0007] The state of wear can be understood to be a current state of the cardiac assist system or of a component of the cardiac assist system (such as a rotor, a plain bearing, an impeller, or a cable) that may affect the functioning of the cardiac assist system. In the case of an impeller, for example, this may be an imbalance of said impeller. The state of wear can also be understood to be a characteristic, such as, for example, the position or location of the cardiac assist system or a component of the cardiac assist system (such as a pump inlet), for example, it can be detected whether the pump inlet is aspirating itself against a blood vessel. The cardiac assist system can be, for example, a right ventricular assist system or a left ventricular assist system, which can be designed as an apical cardiac assist system or as a cardiac assist system for an aortic valve position. The sensor signal can be an electrical or wireless signal, which can be provided, for example, by a sensor device of the cardiac assist system. The sensor device can comprise, for example, a temperature sensor, a pressure sensor, or a voltage sensor, and the sensor signal can represent, accordingly, a temperature, a pressure or a pressure change, or a voltage as an operating state. It is also possible that the sensor signal includes, for example, data from multiple sensors. In the determining step, for example, the sensor signal can be used to extract a sensor parameter set. To evaluate the sensor parameter set, the sensor parameter set can be used to determine a wear signal, which can be an electrical signal comprising as a state of wear, for example, a deviation of a state of wear from a predefined initial state of the cardiac assist system, stored in the form of a processing specification.

[0008] According to one embodiment, at least one wear parameter can be determined in the determining step. The wear signal can include the wear parameter. The wear parameter can include technical data regarding the component of the cardiac assist system, from which, for example, a condition of the component can be deduced. The operating state reflected by the sensor signal can, for example, be evaluated in terms of a time progression. The wear parameter can advantageously be used to analyze the state of wear, for example to predict a time of failure for the cardiac assist system or a component of the cardiac assist system, which increases safety. It is also possible to ascertain the state of wear of a particular component, for example to be able to replace the relevant component instead of replacing the entire cardiac assist system, which advantageously results in resource and cost savings.

[0009] Additionally or alternatively, according to one embodiment, at least one functional parameter representative of the functionality of the cardiac assist system can be determined in the determining step. In this case, the wear signal may comprise the functional parameter. The functional parameter can indicate, for example, whether a further reliable operation of the cardiac assist system is possible or whether replacement or maintenance is necessary. The functionality of the cardiac assist system can therefore advantageously be particularly easily monitored. Thus, impairments of the functionality of the cardiac assist system or of the desired functionality of the cardiac assist system can be detected, for example in order to avoid maintenance of the implanted cardiac assist system or to be able to plan said maintenance in advance, which advantageously increases the safety and reliability of the cardiac assist system.

[0010] According to one embodiment, the method further comprises providing the sensor signal and additionally or alternatively the wear signal to an interface with an external processing device. The external processing device can be, for example, an external control device or a portable device such as a smartphone, or a server or warning device for a cardiac assistance system. The operating state and additionally or alternatively the wear state can therefore advantageously be stored externally, for example for further evaluation. For provision to an interface with a warning device or a smartphone, the wear signal can, for example, comprise functional parameters, and for provision to an interface with an external control device or a server, the wear signal can, for example, comprise wear parameters. The wear signal can also, for example, visually or audibly display the wear signal, additionally comprising functional parameters and wear parameters, for example for provision to an interface with a smartphone. Additionally or alternatively, the wear signal can be determined, for example for provision as a warning signal using predefined limit values ​​as processing specifications and as a function of the result of the comparison with said limit values.

[0011] According to one embodiment, the method may also include a sensing step, in which an operating state is sensed and a sensor signal representative of the operating state is provided. For this purpose, a particular component or a particular area of ​​the cardiac assist system may be sensed, for example by a defined sensor area, in order to ascertain the operating state. Hence, a sensor device for acquiring a sensor signal may advantageously be set, for example, for determining a state of wear of a component of the cardiac assist system, or for determining the state of wear particularly accurately.

[0012] According to an embodiment, the sensor signal can also be sensed using a sensor device. The sensor device can be configured to sense changes in electrical quantities, temperature, pressure, volumetric flow, movement, optical or acoustic signals, force, or position of the cardiac assist system. Voltage can be sensed, for example, as an electrical quantity. Pressure rise or pressure difference can be sensed, for example, as pressure. Vibrations of components of the cardiac assist system can be sensed, for example, as movement or abrupt movement in the form of a fall of the wearer of the implanted cardiac assist system or a physical impact on the wearer. Sensing pressure and volumetric flow is advantageous, for example, to check whether the pump inlet of the cardiac assist system is aspirating itself into the blood vessel. Displacements or malfunctions of the cardiac assist system, such as an imbalance of the impeller, can be identified with the aid of optical or acoustic signals, which can be acquired, for example, by a laser interferometer, a microphone or a structure-borne sound sensor. To sense the aforementioned quantities, the sensor device may comprise, for example, a voltage sensor, an electrical resistance sensor, a temperature sensor, a pressure sensor, an ultrasonic flow sensor, an optical reflection coefficient sensor, a movement sensor, an acceleration sensor, a magnetic sensor, a microphone, a force sensor, a distance sensor, or an inductive and / or capacitive rotor bearing sensor, or a combination of the aforementioned sensors. At least one of the aforementioned sensors may additionally be configured to be redundant, for example for self-diagnosis of the sensor. A sensor integrated into the cardiac assist system can advantageously be used to provide the sensor signal. This is cost-saving and allows for a compact design of the device for carrying out this embodiment of the method.

[0013] According to an embodiment, the sensor signal can also represent the operating state in the time domain and additionally or alternatively in the frequency domain. For this purpose, the sensor signal can represent the operating state within a certain period of time, for example to ascertain the mean value or standard deviation of the operating state. If the sensor signal represents the operating state in the frequency domain, for example, characteristic frequencies of the median frequency of the spectrum, integrated band energy in a defined frequency band, or absolute amplitudes at the location of known damage frequencies can also be determined. Hence, a further analysis of the sensor signal is advantageously possible, which is advantageous for an accurate determination of the state of wear.

[0014] Furthermore, according to one embodiment, a further sensor signal representative of a further operating condition of the cardiac assist system can be read in the reading step, and in the determining step the wear signal can be determined using the sensor signal, the further sensor signal and a comparison rule, which is advantageous in order to be able to determine the state of wear using multiple sensor signals.

[0015] In this case, according to an embodiment, the sensor signal and the further sensor signal can be used to extract in the step of determining a sensor parameter set. The wear signal can be determined using the sensor parameter set and a comparison rule. Determining the sensor parameter set is advantageous for transforming the sensor data in the time domain or the frequency domain.

[0016] According to one embodiment, the method may include a step of defining a comparison rule using the sensor signal. For example, a sensor parameter set may be used to do this. The sensor signal may be used, for example, to create a profile of the operating state or to generate a so-called fingerprint of the system. This embodiment advantageously allows to define the comparison rule using already read sensor signals, for example to set the comparison rule for a specific operating state (for example for the implanted state of the cardiac assist system).

[0017] This approach further introduces a method for operating a cardiac assist system. The method includes the steps of one embodiment of the aforementioned method for detecting a state of wear of the cardiac assist system and the step of providing a control signal for controlling a component of the cardiac assist system. The control signal is output using a sensor signal or a wear signal. Therefore, to detect and optionally evaluate wear of the cardiac assist system, sensor signals already required for normal operation of the cardiac assist system can also be used, i.e. sensor signals required to perform the cardiac assist function of the cardiac assist system. According to this design example, the sensor signals and additionally or alternatively the wear signal can be used to advantageously adapt the components and, as a result, the function of the cardiac assist system, for example, depending on the operating state or the state of wear, in order to reduce or prevent damage to mechanical elements of the cardiac assist system. In case of a detected impact, such as a fall, detected for example by an acceleration sensor or a movement sensor, the sensor signal can be used to slow down the pump of the cardiac assist system, for example, in order to prevent damage.

[0018] The approach presented herein further produces an apparatus configured to execute, control or perform the steps of the method variants for detecting a state of wear of a cardiac assist system presented herein or for operating a cardiac assist system in a corresponding device. This design variant of the invention in the form of an apparatus also makes it possible to quickly and efficiently achieve the underlying objectives of the invention.

[0019] For this purpose, the device may comprise at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or actuator for inputting a sensor signal from a sensor or outputting a data or control signal to an actuator, and / or at least one communication interface for inputting or outputting data embedded in a communication protocol. The computing unit may be, for example, a signal processor, a microcontroller or the like, while the memory unit may be a flash memory, an EEPROM or a magnetic memory unit. The communication interface may be configured to input or output data in a wireless and / or wired manner, whereby a communication interface capable of inputting or outputting wired data may, for example, output said data electrically or optically from a corresponding data transmission line to an input or data transmission line.

[0020] In the present case, the device can be understood as an electrical device that processes a sensor signal and outputs a control signal and / or a data signal as a function of said sensor signal. The device can be equipped with an interface that can be hardware-based and / or software-based. In the case of a hardware-based configuration, the interface can be, for example, part of a so-called system ASIC that contains the various functions of the device. However, it is also possible for the interface to consist of a separate integrated circuit or at least partly of discrete components. In the case of a software-based configuration, the interface can be, for example, a software module provided together with other software modules on a microcontroller.

[0021] Such a device can advantageously be part of or integrated into a cardiac assist system, for example, an embodiment of the device can be integrated into an already functioning cardiac assist system to enable monitoring of the wear state of the cardiac assist system using sensor signals that would be acquired anyway during operation of the cardiac assist system.

[0022] Design examples of the approach presented herein are shown diagrammatically in the drawings and explained in more detail in the following description. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of a cardiac assist system in the aortic valve position according to one design example. [Diagram 2] FIG. 2 is a schematic diagram of an apical cardiac assist system according to one design example. [Diagram 3] FIG. 3 is a schematic diagram of an apparatus for detecting a wear condition of a cardiac assist system according to one design example. [Figure 4] FIG. 4 is a schematic diagram of an apparatus for operating a cardiac assist system according to one design example. [Diagram 5] FIG. 5 is a schematic diagram of a sensor arrangement in a cardiac assist system having an apparatus for detecting a wear condition of the cardiac assist system according to one design example. [Figure 6] FIG. 6 is a flowchart of a method for detecting a wear condition of a cardiac assist system and a method for operating the cardiac assist system according to one design. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In the following description of preferred design examples of the present invention, the same or similar reference numbers are used for elements shown in the various figures, which have similar effect, whereby repeated descriptions of these elements are omitted.

[0025] FIG. 1 shows a schematic diagram of a cardiac assist system 100 in an aortic valve position according to one design. The figure shows a simplified diagram of the cardiac assist system 100 in an implanted state in a heart 105. In the aortic valve position of the cardiac assist system 100 shown herein, a section of the cardiac assist system 100 having an inlet cannula 110 is placed in the left ventricle 115 of the heart 105, and another section of the cardiac assist system 100 is placed in the aorta 120 in the region of the aortic valve 125. A pump volume flow 130 is received at the tip of the inlet cannula 110 in the ventricle 115 and is discharged in the region of the aorta 120. One design of the cardiac assist system 100 shown herein includes a device for detecting a state of wear or for operating the cardiac assist system 100, as shown with reference to FIGS. 3 and 4 described below.

[0026] FIG. 2 shows a schematic diagram of an apical cardiac assist system 100 according to one design example. The figure shows a simplified diagram of the cardiac assist system 100 in an implanted state. The apical cardiac assist system 100 comprises an inlet for introducing blood flow, which pumps blood flow from the left ventricle 115 of the heart to the aorta 120 via a drain cannula 205 that is led along the outside of the heart 105. For this purpose, a pump volumetric flow 130 is delivered to the drain cannula 205 by a pump of the cardiac assist system 100, for example a rotary pump. The drain cannula 205 delivers the pump volumetric flow 130 to the aorta 120. One design example of the apical cardiac assist system 100 shown herein also includes a device for detecting a state of wear or for operating the cardiac assist system 100, as shown with reference to FIGS. 3 and 4 described below.

[0027] 3 shows a schematic diagram of an apparatus 300 for detecting a state of wear of a cardiac assist system according to one design example. The apparatus 300 includes a reading device 305 and a determining device 310. The reading device 305 is configured to read a sensor signal 315 representative of an operating state of the cardiac assist system. The determining device 310 is configured to determine a wear signal 325 using the sensor signal 315 and a comparison rule 320. The wear signal 325 represents a state of wear.

[0028] The device 300 illustrated herein may be used in conjunction with a cardiac assist system, such as one of the two cardiac assist systems illustrated as examples in FIGS. 1 and 2 above.

[0029] According to one design example, the determining device 310 is configured to determine at least one wear parameter and provide a wear signal 325 including the wear parameter. Additionally or alternatively, the determining device 310 is configured to determine at least one functional parameter indicative of functionality of the cardiac assist system and provide a wear signal 325 including the functional parameter.

[0030] According to the design example presented herein, the determining device 310 is also configured to provide a wear signal 325 to an interface with an external processing device 335. The sensor signal 315 is also optionally provided to an interface with the external processing device 335. The interface can be wireless or wired.

[0031] According to the design example shown herein, the reading device 305 is also configured to read at least one further sensor signal 330, which represents a further operating condition of the cardiac assist system. The determining device 310 is configured to determine the wear signal 325 using the sensor signal 315, the at least one further sensor signal 330, and the comparison rule 320. The determining device 310 is also optionally configured to extract a sensor parameter set using the sensor signal 315 and the at least one further sensor signal 330, and to determine the wear signal 325 using the sensor parameter set and the comparison rule 320. According to the design example shown herein, the comparison rule is pre-stored in the determining device. The comparison rule 320 is optionally defined using the sensor signal 315.

[0032] According to the design example presented herein, the sensor signal 315 and the further sensor signal 330 are provided by a sensor device 340. The sensor device 340 is optionally configured to sense an operating condition and provide a sensor signal 315 representative of the operating condition. According to one design example, the sensor device 340 is also configured to sense a change in an electrical quantity, a temperature, a pressure, a volumetric flow rate, a movement, an optical or acoustic signal, a force, or a position of the cardiac assist system to provide the sensor signal 315. According to one design example, the sensor signal 315 is configured to represent an operating condition in the time domain and additionally or alternatively in the frequency domain.

[0033] In combination with a cardiac assist system, the device 300 shown herein can be used to monitor at least one functional group of the cardiac assist system so that a maintenance intervention can be performed before the occurrence of a first symptom or a serious emergency. The sensor device 340 can be, for example, a sensor device integrated into the cardiac assist system and can be configured to determine operating parameters such as current, voltage, temperature, vibration, pressure and pressure changes, sound, optical reflection coefficient, force, and position changes. According to one design example, the sensor parameters are extracted from the sensor data using the determination device 310, for example in the time domain and additionally or alternatively in the frequency domain.

[0034] A fingerprint of the system may be generated, so to speak, from the determined sensor parameter set, or the sensor parameter set may itself be a fingerprint. Using the decision device 310, the fingerprint may be continuously compared with a definition of a healthy fingerprint in the form of a comparison rule 320. Deviations of the fingerprint from the healthy fingerprint of the comparison rule 320 are indicative of an ongoing aging or damage process of the cardiac assist system. The temporal progression of the sensor parameter set is optionally employed using the decision device 310 to evaluate the wear process of the cardiac assist system and possibly predict the time to failure. According to the design example shown herein, the decision device 310 is configured to provide a wear signal 325 to an interface with an external processing device 335, and informs, for example, a wearer, a patient, or a physician of the implanted cardiac assist system having the device 300, via the wear signal 325 representing a state of wear, in case of deviations from the normal fingerprint identified by the wear signal 325, for example in the form of a wear signal 325 including wear parameters.

[0035] Such monitoring of the cardiac assist system's status using variants of the device 300 shown herein advantageously allows for reduction or even prevention of serious system failures to be achieved. Early detection of system degradation provides a time advantage, so that, for example, surgical appointments for component replacement can be scheduled early. Predictive maintenance intervention improves the patient's quality of life by not exposing them to medical emergency scenarios. The device 300 shown herein can also be referred to as a condition monitoring system and provides additional protection measures, especially for subsystems that cannot be configured to be redundant, such as pump motors. Incorporating the device 300 as a condition monitoring system can increase the patient's confidence in their assist system, which provides peace of mind.

[0036] The wear signal 325 can be used to transmit the determined state of wear via an interface to an external processing device 335 in the form of a communication interface such as a wireless modem or a wired interface. If the external processing device 335 comprises a display device of a so-called "wearable" for example in the form of a screen of an external control device or portable device (such as a smartphone connected via Bluetooth Low Energy as the external processing device 335), the state of wear provided by the wear signal 325 can be displayed on the display device, for example in the form of a status scale of the state of wear.

[0037] By providing a wear signal 325 to an interface with an external processing device 335, the wear state and / or the underlying sensor values ​​or parameters can additionally or alternatively be stored in an external control device or a control device embedded with the cardiac assist system for later retrieval (via a cable, wireless or inductively coupled communication interface) and / or transmitted to a central server via a wide area network (e.g. WLAN, LTE or GPRS). The use of a central server has the advantage that the system fingerprint transmitted by the wear signal 325 and the progress of the trends of the wear state and the parameters of the sensor data can be compared with a large population of systems, so that robust statements can be made about the system state of the cardiac assist system.

[0038] Fig. 4 shows a schematic diagram of an apparatus 400 for operating a cardiac assist system according to one design example. The apparatus 400 shown herein is configured to operate and additionally or alternatively control a cardiac assist system, such as the cardiac assist system shown by way of example with reference to Fig. 1 or Fig. 2. To this end, the apparatus 400 comprises a reading device 305 and a determining device 310, which substantially correspond to the reading device and determining device shown in Fig. 3. The reading device 305 is correspondingly configured to read a sensor signal 315 provided by the sensor device 340, and the determining device 310 is configured to determine and provide a wear signal 325 using the sensor signal 315 and the comparison rule 320.

[0039] According to the design example presented herein, the device 400 also includes a controller 405. The controller 405 is configured to use the sensor signal 315 or the wear signal 325 to provide a control signal 410 for controlling a component 415 of the cardiac assist system.

[0040] The cardiac assist system components 415 are, for example, a control unit or structural elements such as a pump or impeller or driver as shown in Fig. 5 below. If the device 400 detects a patient fall or other physical impact by the sensor signal 315 and additionally or alternatively by determining the wear signal 325 using the determining device 310, the device 400 is configured to use the controller 405 to control one of the cardiac assist system components 415, such as the pump, by the control signal 410 to temporarily slow down or stop the pump to prevent or reduce damage to mechanical elements.

[0041] Fig. 5 shows a schematic diagram of the arrangement of sensors of the cardiac assist system 100 relative to an apparatus 300 for detecting a state of wear of the cardiac assist system 100 according to one design example. The sensor integration examples shown in this specification can also be implemented in conjunction with an apparatus 400 for operating the cardiac assist system 100. The cardiac assist system correspondingly comprises an apparatus 300; 400, which is similar or identical to the variants of the apparatus described with reference to Figs. 3 and 4 above, for example. By way of example, the cardiac assist system 100 shown in this specification is shown as a cardiac assist system for the aortic valve position, like the cardiac assist system described with reference to Fig. 1.

[0042] The cardiac assist system 100 comprises a tip 505, an inlet cage 510 for receiving a blood volume flow, an inlet cannula 515 for delivering the blood volume flow to the micro-axial pump, an impeller 520 of the micro-axial pump, a magnetically or mechanically coupled electric drive 525, a supply cable 530 and a control unit 535. The control unit 535 includes, for example, the devices 300; 400. By way of example, the cardiac assist system 100 comprises various sensors as a sensor device in an example of an installation position. According to the design example shown here, the cardiac assist system 100 comprises three temperature sensors 542, two of which are arranged in the area of ​​the electric drive 525 and one of which is arranged in the area of ​​the tip 505. By way of example, the cardiac assist system 100 also comprises three pressure sensors 544, one of which is arranged in the area of ​​the tip 505, one of which is arranged in the area of ​​the inlet cannula 515 and one of which is arranged in the area of ​​the electric drive 525. In the region between the tip 505 and the inlet cage 510, the cardiac assist system also comprises an ultrasonic flow sensor 546. At the end facing away from the tip 505, the inlet cannula 515 additionally comprises a force, bending or distance sensor 548 and an optical reflection coefficient sensor 550. Adjacent to the impeller 520, the electric drive 525 comprises an impeller position sensor 552 in the form of a magnetic or Hall sensor, an optical distance sensor such as a laser interferometer, or an inductive rotor sensor and additionally or alternatively a capacitive rotor position sensor. In the middle of the electric drive 525, the cardiac assist system 100 comprises a vibration sensor, a structure-borne sound sensor, a microphone and additionally or alternatively a microcontroller, for example in the form of a sensor hub, as a further impeller position sensor 554. In the region of the contact point of the control unit 535 with the supply cable 530, the cardiac assist system comprises a voltage sensor 556 in the form of a voltage, current, power, electrical resistance and / or back EMF sensor. The control unit 535 further comprises a control device sensor 558 in the form of a microphone, a pressure, acceleration and / or rotational speed sensor, or a temperature sensor.

[0043] The redundant design of the sensors 542, 544, 546, 548, 550, 552, 554, 556, and 558 shown herein is advantageous for self-diagnosis of the sensors 542, 544, 546, 548, 550, 552, 554, 556, and 558 using deviations between the individual sensor values. The incorporation of all of the sensors 542, 544, 546, 548, 550, 552, 554, 556, and 558 shown herein may not make sense in all applications or may not be implementable in all applications for reasons of installation space or cost. The most relevant sensors may be selected in a targeted manner depending on the particular application, for example, based on a failure mode and effect analysis (FMEA analysis) or based on failures observed in long-term or stress tests.

[0044] The following is a list of examples of applications of the devices 300, 400 in conjunction with the cardiac assist system 100 and a sensor device, such as one or more of the sensors 542, 544, 546, 548, 550, 552, 554, 556 and 558 shown herein, for detecting a wear condition of the cardiac assist system 100 and / or for operating the cardiac assist system 100.

[0045] An impeller sensor 554 in the form of a microphone or structure-borne sound sensor, and additionally or alternatively a controller sensor 558 in the form of a microphone and / or acceleration sensor, enable analysis of bearing wear by determining the state of wear.

[0046] In the case of a magnetically coupled and magnetically mounted impeller 520, aging and deposits, as well as the onset of pump thrombosis, can result in imbalance of the impeller 520, which can be detected via the microphones, acceleration sensors, rotational speed sensors, and structure-borne sound sensors of the impeller sensor 554 and / or controller sensor 558.

[0047] For example, a change in friction of the plain bearings of cardiac assist system 100 as a result of wear or deposit build-up can be detected by a change in power consumption, which can be sensed by a voltage sensor 556 in the form of a current, voltage or power sensor in combination with an actual pressure rise or volumetric flow rate rise, which can be sensed by one of the pressure sensors 544 in the area of ​​inlet cannula 515 or electric drive 525 or by ultrasonic flow sensor 546. This error pattern also leads to characteristic vibrations, which can be detected by microphones, acceleration sensors, rotational speed sensors and structure-borne sound sensors of impeller sensor 554 and / or controller sensor 558.

[0048] Measurement of slip between the magnetically coupled drive 525 and impeller 520 provides information about the condition of the coupling and the plain bearing of the impeller 520. The slip can be sensed, for example, via an optical, magnetic, or capacitive impeller position sensor 552, or the phase relationship of the electric drive current and the back induced electric field energy (back EMF) at the currentless rotation of the polyphase electric motor 525 can be sensed, for example, by a voltage sensor 556 in the controller 535 or electric drive 525. For this purpose, the voltage sensor 556 can be placed in the area of ​​the electric drive 525 at the location shown herein or at the location of the temperature sensor 542 or pressure sensor 554 located therein.

[0049] The load on the bearings and the resulting pressure rise in the impeller 520 can also be sensed at the impeller bearings by force, strain, or distance sensors 548 .

[0050] The onset of deposits and pump thrombosis can be detected via a pressure drop in the inlet hose in the form of the inlet cannula 515, for example via a pressure gradient between the aorta and the inlet cannula 515 or the ventricle, but also via a comparison of the power consumption detectable by the voltage sensor 556 with the actual flow detectable by the ultrasonic flow sensor 546, and via a pressure rise in the pump detectable by the pressure sensor 544.

[0051] An indication of the ageing process of the stator of the electric drive 525 is provided, for example, by the winding temperature, which can be detected by a temperature sensor 542 positioned in the area of ​​the electric drive 525, or the winding impedance, which can be detected by a voltage sensor 556, but also by the optically, inductively or capacitively measured dimension of the motor air gap, measured by an impeller position sensor 552 at the location of the temperature sensor 542 or the pressure sensor 544, located in the area of ​​the electric drive 525.

[0052] Deposits on the rotor, as well as imbalances, can also be determined through optical measurements of the reflectance coefficient using the reflectance coefficient sensor 550 .

[0053] The quality of the supply cable 530 can be monitored via electrical resistance measurements by voltage sensor 556. In addition to detecting cable cuts (series measurements), resistance measurements can also be performed as complex-valued impedance measurements between adjacent wire strands to assess the condition of the insulating jacket and / or dielectric.

[0054] Faults in the power and signal electronics of the controller 535 can be detected by measuring the temperature of the individual assemblies and monitoring selected voltage levels.

[0055] The suction of the pump inlet to the ventricular wall of the aorta in the cardiac assist system 100 at the aortic valve position, the so-called "suction", can also be detected by the devices 300, 400 shown here. If the cardiac assist system 100 is suctioning, an auxiliary blood volume flow is no longer possible and the cardiac assist system 100 should (automatically) reduce the pump power until it is released from the aortic wall. Suction can be detected via the pressure gradient of the pressure sensors in the area of ​​the tip 505 and the area of ​​the inlet cannula 515 and by the ultrasonic flow sensor 546. Partial closure of the inlet cage 510 also changes the flow conditions in the inlet cage 510, which can be detected via the Doppler spectrum of the ultrasonic flow sensor 546.

[0056] The sensor data processing by the decision device of the device 300, 400 is based on the analysis of the sensor signal in the time domain, for example, via relative or absolute thresholds, mean values, standard deviations, minimum and maximum values ​​during a time frame or the entire observation period. Additionally or alternatively, the sensor data processing by the decision device of the device 300, 400 is based on the analysis of the sensor signal in the frequency domain, for example, via the determination of a characteristic frequency, a median frequency of the spectrum, an integrated band energy in a defined frequency band, or an absolute amplitude at the location of a known damage frequency. The sensor parameters of the operating state mentioned above can be determined as condition parameters (i.e., as wear parameters, for example) based on predefined thresholds of a comparison rule. Alternatively, a fingerprint of a system parameter may be defined as a comparison rule, for example, a threshold can be defined in a mathematical distance measure on a fingerprint defined as healthy (for example, as a threshold hyperplane in a multidimensional parameter space).

[0057] Processing of the sensor values ​​can be accomplished in a pump integrated microcontroller or controller 535, such as a sensor hub. The sensor hub can also be used only to pre-process the sensor data and transfer the extracted sensor parameters, which reduces the communication bandwidth required along the supply cable 530.

[0058] FIG. 6 shows a flow diagram of a method 600 for detecting a wear condition in a cardiac assist system and a method 700 for operating the cardiac assist system according to one design example.

[0059] The method 600 includes a reading step 601 and a determining step 603. In the reading step 601, a sensor signal representative of an operating condition of the cardiac assist system is read. In the determining step 603, a wear signal is determined using the sensor signal and a comparison rule. The wear signal is representative of a state of wear.

[0060] According to one design example, at least one wear parameter is determined in determining step 603. In this case, the wear signal includes the at least one wear parameter. In determining step 603, at least one functional parameter representative of functionality of the cardiac assist system is optionally determined as well. The wear signal then includes the at least one functional parameter.

[0061] Method 600 also optionally includes providing 605 the sensor signal and / or the wear signal to an interface with an external processing device. Providing 605 optionally occurs after determining 603. If only a sensor signal is provided in providing 605, providing 605 can also occur after reading 601.

[0062] According to one design example, method 600 further includes a sensing step 607, in which an operating condition is sensed and a sensor signal representative of the operating condition is provided. The sensing step 607 optionally occurs before the reading step 601. The sensing step 607 may additionally or alternatively be performed before the providing step 605.

[0063] In the reading step 601, a further sensor signal representative of a further operating condition of the cardiac assist system is optionally read. In this case, a wear signal is determined in a determining step 603 using the sensor signal, the further sensor signal, and a comparison rule. A sensor parameter set is also optionally extracted in a determining step 603 using the sensor signal and the further sensor signal. Then, a wear signal is determined using the sensor parameter set and the comparison rule.

[0064] According to one design example, method 600 further includes defining 609 the comparison rule using the sensor signal. Defining 609 is optionally performed after reading 601 and before determining 603.

[0065] Method 700 for operating a cardiac assist system includes at least steps 601 and 603 of method 600, and optionally one or more of steps 605, 607, and 609, as described above. Method 700 further includes step 701 of providing a control signal for controlling a component of the cardiac assist system. The control signal is provided using a sensor signal or a wear signal.

[0066] When a design example includes an "and / or" conjunction between a first feature and a second feature, this should be read to mean that, according to one embodiment, the design example includes both the first feature and the second feature, and according to another embodiment, the design example includes either only the first feature or only the second feature.

Claims

1. 1. A method for detecting a wear condition in a cardiac assist system, comprising: determining a first operating state of the cardiac assist system implanted in the heart; receiving a first sensor signal at a first time associated with the first operating state associated with an impeller of the cardiac assist system following implantation of the cardiac assist system in the heart; receiving a second sensor signal at a second time associated with a second operating state of a component of the cardiac assist system; determining a comparison rule associated with a second operating state based on the initial operating state; determining a wear signal associated with a wear status of the cardiac assist system based at least in part on the first sensor signal, the second sensor signal, and the comparison rule; and controlling the component of the cardiac assist system associated with the second sensor signal with a control signal based on the wear signal to control the speed of the impeller.

2. The method of claim 1 , wherein the first sensor signal is related to deposits on the impeller or an imbalance of the impeller.

3. The method of claim 1 , wherein the first sensor signal is related to at least one of a position, a vibration, an acceleration, a pressure, a rotational speed, a temperature, a voltage, a current, a power, an optical reflection, or an electrical resistance associated with the impeller.

4. The method of claim 1 , wherein the second sensor signal is associated with an inlet cannula of the cardiac assist system.

5. The method of claim 4 , wherein the second sensor signal is related to a change in flow or pressure in the inlet cannula.

6. The method of claim 1 , further comprising providing the first sensor signal or the wear signal to an external processing device.

7. The method of claim 1 , wherein the first sensor signal represents the operating condition of the cardiac assist system in a time domain or a frequency domain.

8. 2. The method of claim 1, further comprising determining a characteristic vibration in the change of the first operating state of the cardiac assist system, the characteristic vibration being associated with an error pattern in the first operating state.

9. The method of claim 1 , further comprising determining the comparison rule based at least in part on the first sensor signal.

10. generating a fingerprint based at least in part on the first sensor signal; comparing the fingerprint to a clean fingerprint based at least in part on the comparison rules; The method of claim 1 , further comprising determining the wear signal based at least in part on a comparison of the fingerprint to the healthy fingerprint.

11. generating a control signal based at least in part on the wear signal and configured to control a component of the cardiac assist system; The method of claim 1 , further comprising transmitting the control signal to control a component of the cardiac assist system.

12. 1. A system configured to determine a wear status of a cardiac assist system, comprising: a reader configured to receive, following implantation of the cardiac assist system in the heart, a first sensor signal at a first time associated with a first operating state of an impeller of the cardiac assist system and a second sensor signal at a second time associated with a second operating state of a component of the cardiac assist system; a determining device configured to determine a functional parameter indicative of further reliability of the cardiac assist system and to determine a wear signal indicative of a current wear of the cardiac assist system based at least in part on the first sensor signal, the second sensor signal and a comparison rule; a control device configured to generate and send to the cardiac assist system a control signal based on the wear signal and associated with the second sensor signal, the control signal being configured to control the component of the cardiac assist system to control a speed of the impeller.

13. The system of claim 12 , wherein the first sensor signal is associated with an impeller of the cardiac assist system.

14. The system of claim 12 , wherein the first sensor signal represents the operating condition of the cardiac assist system in a time domain or a frequency domain.

15. The system of claim 12 , wherein the second sensor signal is associated with an inlet cannula of the cardiac assist system.

16. 1. A cardiac assist system comprising: an inlet cannula for supplying a volumetric flow of blood to the flow pump; an impeller of the flow pump; 1. An apparatus configured to determine a wear status of a cardiac assist system, comprising: a reader configured to receive, following implantation of the cardiac assist system in the heart, a first sensor signal at a first time associated with a first operating state of the impeller of the cardiac assist system and a second sensor signal at a second time associated with a second operating state of a component of the cardiac assist system; a determining device configured to determine a functional parameter indicative of further reliability of the cardiac assist system and to determine a wear signal indicative of a current wear of the cardiac assist system based at least in part on the first sensor signal, the second sensor signal and a comparison rule; and a controller configured to generate and send a control signal to the cardiac assist system, the control signal being based on the wear signal and configured to control the component of the cardiac assist system associated with the second sensor signal to control a speed of the impeller.

17. 17. The system of claim 16, wherein the first sensor signal is related to an operating condition of the impeller of the cardiac assist system.

18. The system of claim 16 , wherein the first sensor signal represents the operating condition of the cardiac assist system in a time domain or a frequency domain.

19. 17. The system of claim 16, wherein the second sensor signal is related to an operational state of the inlet cannula of the cardiac assist system.

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