Device and method for determining cardiac function in a living organism

Abstract

To provide a system, a method, an algorithm, and an auxiliary part for determining a heart pump function.SOLUTION: A medical catheter, a sheath, and a shaft hold a device of an integral digital sensor system on-chip (SoC) in a part existing in the body. In the part of the device existing in the body, a complete chain of signal conversion, signal analog / digital conversion, and digital signal transmission are combined to cause single and a plurality of physical emitters in a single set-up to be acquired. A wireless data transmission functionality is assembled and, in a specific example, wireless environmental power generation for environmental power generation without a battery is assembled. An auxiliary monitor system suited to reception, processing and analysis of data acquired by a catheter / sheath / shaft for bringing robust evaluation of cardiac performance is evaluated. This relates to innovation that makes such a system applicable to a patient with / without the cardiac auxiliary device.SELECTED DRAWING: Figure 2

Description

[Background technology]

[0001] The pumping action of the heart is a fundamental vital function of the body, and its accurate determination is important in many medical conditions, sports, and other applications. Cardiac output, defined as the integrated forward flow of blood from the left ventricle over a time interval, correlates in a highly nonlinear manner with various measurable biological parameters. This correlation is further influenced by the presence and activity of artificial devices, e.g., cardiac assist pumps, at various locations in the circulatory system. Several clinical measurement techniques for cardiac pumping function exist, such as cardiac catheterization, thermodilution, and pulse waveform analysis; however, all methods have inherent limitations, such as inaccuracy, ineffectiveness, invasiveness, and practical difficulties in clinical application.

[0002] The need for new catheters Determination and monitoring of cardiac performance, particularly cardiac output, often relies on assessment of a single key physiological parameter that is taken as a surrogate for the (inaccessible) cardiac output parameter of interest.

[0003] Typically, measuring parameters for calculating cardiac output (CO) relies on invasive catheters. Such catheters often contain either fluid lines transmitting internal pressure to sensors outside the body, optical lines transmitting optical signals from internal measurement locations to external sensors, or electrical lines transmitting analog signals from within the body (e.g., from a thermistor) to external analog-to-digital converters. The transmission of physical or analog signals from within the body to external transducers is prone to mechanical or electrical noise, such catheters are often difficult and expensive to manufacture, their handling in clinical practice is laborious, and the multiple connections (analog wires, fluids) and external power and signal transport lines required for functionality complicate patient management.

[0004] Therefore, future systems for cardiac output determination should innovate catheter designs to overcome these limitations.

[0005] The use of a single parameter for determining cardiac output, as is typically done using thermodilution or pulse contour analysis, has several drawbacks: 1) The surrogate parameters may not accurately represent the necessary but inaccessible cardiac function parameters. 2) Alternative values ​​may be confounded by other physiological and technical parameters. 3) Relying on a single sensor makes this method sensitive to sensor errors such as noise, drift, sensor inaccuracy, and sensor displacement. 4) Cardiac assist systems, whether implanted, external, or percutaneous catheter-based, are typically a major confounder of currently used algorithms for calculating cardiac output (CO).

[0006] The need for multiple parameters and integrated analysis of these parameters In contrast, cardiac function determination methods based on the combination of multiple biological signals may overcome the aforementioned weaknesses to some extent by delivering a more robust primary signal and allowing for control of confounding factors. One important practical limitation of current clinical practice when monitoring multiple vital parameters is that this results in increased complexity in patient management, as each additional sensor typically carries its own cable for power and sensor signal output, thereby increasing complexity and cost.

[0007] Therefore, future systems for cardiac output determination should preferably have the ability to a) acquire multiple signal modalities in a synchronized manner with a minimal amount of equipment, b) combine and analyze multiple signal parameters, and c) be applicable and reliable to patients receiving mechanical circulatory support.

[0008] This suggests the need for innovation in cardiac monitoring devices and algorithms used with the catheters / sheaths / shafts of the present invention.

[0009] prior art Most currently state-of-the-art monitoring catheters are capable of probing a single physical modality within the body, which in a typical scenario is guided outside the body where an external transducer converts the physical signal into an analog signal which is then further converted into a digital signal, a typical example being current invasive pressure monitor catheters.

[0010] Additionally, there are medical pressure wires that can be placed inside the body to measure a single signal; these medical pressure wires convert pressure at the tip of the wire by converting it to an analog signal inside the body and then directing this analog signal to a catheter portion outside the body; this device must be connected to a second device (interface box) outside the body for analog-to-digital signal conversion and data transmission (Radi Patent, 1997, patents.justia.com / patents / 6112598), (Volcano Patent, 2002, http: / / patents.justia.com / patent / 6976965). There are medical Doppler wires that allow extraction of a single ultrasonic Doppler signal from the body by reading not only low-frequency pressure but also high-frequency pressure oscillations through a similar catheter; in this case, the analog signal is directed from the catheter tip to a location outside the body, where additional equipment is required for analog-to-digital conversion (Volcano Patent, 2002, http: / / patents.justia.com / patent / 6976965). In addition, there are a limited number of medical multi-mode sensing catheters, which typically have an analog sensing element and several channels of fiber guiding physical signals (pressure, light) from the body that are converted to electrical signals outside the body. One example is the CCOmbo / SvO2 pulmonary artery catheter from Edwards Life Science. The CCOmbo / SvO2 pulmonary artery catheter combines an analog temperature-sensing thermistor at the tip of the catheter inside the body, a fluid-filled lumen that allows pressure determination outside the body, an additional external pressure transducer, and an optical fiber that guides the optical spectrum outside the body, thereby translating the physical signals into a digital information stream, while the actual optical sensor is located outside the body.

[0011] Prior art monitors for calculating cardiac output, the main method currently used, are the pulmonary artery catheter, the PiCCO system and the pulmonary form, which are the main bodies of prior art.

[0012] a) Pulmonary Artery Catheter Details: Pulmonary artery catheters have long been considered the mainstay of cardiac output monitoring in clinical practice, despite their notoriously inaccurate nature in various situations. The simplest pulmonary artery catheter measures the temperature curve in the pulmonary artery after injecting a cryogenic fluid into the right atrium. Pulmonary artery catheters are often difficult to place, pose a risk of infection and pulmonary artery injury, and have large measurement variability, especially when tricuspid valve insufficiency is present, as in the most critically ill patients. The alternative Fick method for cardiac output determination relies on the oxygen content of blood extracted from the pulmonary artery by the pulmonary artery catheter and in the arterial circulation. This method is unreliable because it relies on knowledge of systemic oxygen consumption (which typically varies in ill patients). Yet another method is continuous monitoring of central venous oxygen saturation with a fiberoptic catheter. Because this parameter depends on many confounding factors unrelated to cardiac output, it is not considered a good surrogate for cardiac output. All these mentioned pulmonary artery catheter-based methods are old and are covered by multiple expired patents.

[0013] b) PiCCO System Details: The PiCCO system relies on bolus thermodilution measurements in a central artery after injection of a cryogenic fluid bolus into a central vein, thus requiring a separate central vascular catheter. Technically, the PiCCO system consists of a thermistor on the tip of the catheter, an external signal digitizer, and data transmission in a separate external module. Additionally, PiCCO can use blood pressure profiles guided out of the central artery through a fluid-filled lumen, thereby monitoring using an external pressure transducer, followed by an external analog-to-digital converter and data transmission.

[0014] c) HighDim prior art (U.S. Patent Application No. 13 / 827,063) describes an apparatus and method for calculating cardiac output based on multi-parameter physiological data that is analyzed using multidimensional nonlinear optimization to calculate cardiac output. A limitation of this method is that it does not consider cases where a circulatory assist device, such as an implantable heart pump, contributes to an individual's cardiac output. In such cases, the true cardiac output is underestimated because the mechanical contribution is not taken into account. Furthermore, the implantable heart pump induces changes in the circulatory system that are not considered in the algorithm learning process described in (U.S. Patent Application No. 13 / 827,063).

[0015] Improvements in medical monitoring technology are desirable as innovations can lead to improved patient management.

[0016] Measuring multiple physical signals at locations within the body can yield information suitable as input to algorithms and systems that can exploit the complementary, redundant, and interdependent information content of the signals, as described below.

[0017] Definition of Terms The expression "inside the body" is intended to encompass any setting in which a medically invasive device is inserted into one of a blood vessel, a body cavity, and a bodily tissue, either entirely or exclusively within its body.

[0018] Catheter means a hollow tube less than 1 centimeter and more than 100 micrometers in diameter whose primary function is to connect a body compartment (typically an intravascular compartment) to the outside of the body for one of the following goals: infusion of therapeutic fluids through a water column guided outside the body, withdrawal of blood, and measurement of hydrostatic pressure.

[0019] Sheath means a hollow tube having a diameter of less than 1 centimeter and greater than 100 micrometers that serves to contain an inner elongated object within a main lumen of the hollow tube and guide the inner elongated object from outside the body into the body. In addition to the main lumen for carrying the object, such a sheath may contain zero or more additional hollow lumens for other purposes.

[0020] Shaft means an elongated object less than 1 centimeter and greater than 100 micrometers in diameter, the primary function of which is to carry several functional subsystems, including at least one of a pump and a sensor array, within the portion of the shaft that is within the body, where C / S / S stands for "catheter, sheath, shaft."

[0021] A miniaturized digital sensor system-on-chip (SoC) as described herein combines the circuitry necessary to provide digital encoding of a quantitative measurement of a physical modality, including at least signal-to-analog conversion, analog-to-digital conversion, and digital transmission, in an integrated package having a diameter measured orthogonal to the device axis no larger than the space available at the target location in the body (typically less than 5 square millimeters for catheters and shafts placed solely for diagnostic purposes, and typically less than 20 square millimeters for sheaths used with heart pumps). The use of such miniaturized digital sensors has the advantages of: a) eliminating noise- and bias-prone analog signal transmission; b) reducing the number of noise sources due to the integrated conversion and digitization sensor elements; c) allowing digital multiplexing of multiple sensor outputs to minimize the number of signal lines; d) simplifying the manufacture of catheters, sheaths, and shafts due to the fewer electrical connections required; and e) providing digital sensors with very low power requirements. The size limitations of these sensors are important because clinically acceptable vascular access sizes are limited, typically ranging from 0.5 to 3 mm in device diameter for purely diagnostic applications, up to 5 mm for the shafts of circulatory assist devices, and up to 8 mm for catheters used in extracorporeal circulation. The power requirements of the sensor are important for clinical applications and are preferably low to simplify the power supply and avoid clinically undesirable overheating of the sensor.

[0022] computer In the context of the present invention, the term "computer" can relate to any suitable computing system. In particular, the computer can be a desktop computer, a laptop computer, a tablet, a smartphone, or similar device, as well as an embedded computing system such as a microcontroller or any other single or multi-processor embedded system.

[0023] Energy Harvesting Energy harvesting is used to describe a process in which a device extracts electrical energy from a physical energy source in the device's surroundings without having a wired connection to the energy source. Energy harvesting techniques are well known to practitioners in the field. In the context of this patent, the term "coil" refers to an electrical coil.

[0024] Heart pump A cardiac pump is defined as a medical device that pumps blood from one compartment of the blood circulation to another compartment of the blood circulation. Typical pumps include a) extracorporeal pumps, which have mechanical pumping components outside the body, b) catheter-based pumps, which have mechanical pumping components inside the body and are attached to the end of a shaft that crosses the skin, and c) totally implantable pumps, which have mechanical pumping components inside the body and have no parts except for a power cable that crosses the skin.

[0025] Deep Neural Networks In the field of machine learning, a deep neural network (DNN) is an artificial neural network (ANN) that has multiple hidden layers of units between the input and output layers.

[0026] Deep Belief Network In the field of machine learning, deep believe networks are typical of deep neural networks, containing multiple layers of latent variables with connections between layers but no connections between units within each layer. Summary of the Invention

[0027] According to the present invention, the need for a more accurate measurement of signals that reflect the patient's cardiac performance and allow extraction of cardiac output parameters that are better representative of cardiac output is solved by a medical invasive device, the method and apparatus for calculating such cardiac output being defined by the features of the respective independent claims. Preferred embodiments are the subject of the dependent claims.

[0028] In particular, the present invention deals with an innovative setup for a medical invasive device where, for example, signal conversion, analog-to-digital signal conversion, and digital signal transmission are transferred into a portion of a catheter configured to be located inside a blood vessel lumen by using a miniaturized digital sensor SoC.

[0029] Thus, medical digital sensor SoC arrays are attached to catheters, sheaths, and shafts at locations within the body.

[0030] The benefits to be gained from such an innovative setup include 1) reducing or eliminating the need for extracorporeal signal transducer modules, thus simplifying industrial production, distribution, and clinical use, and 2) eliminating the need for electrical wires carrying sensitive analog signals and hydrostatic columns for pressure propagation of optical lines for signal transmission.The proposed setup consists of a device in the form of a catheter, sheath, or shaft with a miniaturized digital sensor at its tip, which performs the steps of physical signal sensing, signal transduction, analog / digital signal conversion, and digital signal transmission at a location placed inside the body.

[0031] Additionally, multiple sensors SoC measuring various auxiliary physical signals may be located within portions of medical catheters, sheaths, and shafts adapted for placement within the body according to the present invention.

[0032] The sensors used in connection with the present invention are described in more detail below. In line with the above innovative configuration, medical digital sensor SoC and SoC array devices are provided in which the sensors are attached to parts of a medical invasive device located inside the body, thus forming an integrated multi-mode sensor array for vital biosignal monitoring that can be integrated into one of the following: a) Shaft of the circulatory assist device b) Freestanding shaft c) Sheath across the blood vessel d) Intravascular catheter

[0033] Some useful sensor combinations are possible, including the following as non-limiting examples:

[0034] Integration has the advantage of reducing the number of patient access cables to one per sensor array, resulting in improved practicality in clinical scenarios.

[0035] Additionally, in the following, devices are described in the form of medical catheters, sheaths, and shafts that incorporate a digital interface in a portion configured to be located outside the body and a digital sensor SoC arrangement with digital transmission in a portion configured to be placed inside the body, thereby allowing connection of a connector cable for power supply and digital data transfer.

[0036] While the embodiments contemplated by the above aspects of the present invention already simplify and improve medical monitoring, it would still be desirable to forgo wired power and communication. For these reasons, further improvements are desirable.

[0037] According to another aspect of the present invention, a wireless transmitting catheter and / or sheath and / or shaft can be designed with integrated medical sensor SoCs and SoC arrays, such that the integrated multi-modal biomedical sensor array can be powered by an integrated battery and read out by wireless data transmission.

[0038] Thus, a further aspect of the present invention comprises a medical catheter, sheath, or shaft, in which, in a single embodiment, a miniaturized digital sensor SoC device in the portion configured to be located inside the body is combined with a wireless communication chip and a miniaturized battery in the portion configured to be located outside the body. This allows for the elimination of the need for cables for power and communication, greatly improving clinical practicality. It also improves electrical safety because no metallic connection to the patient is required.

[0039] According to further possible embodiments of the present invention, medical catheters, sheaths, and shafts can be designed with a connector combined with a miniaturized digital sensor device configured to be located inside the body and a pluggable module with a miniature battery and electronics for wireless signal transmission.

[0040] This has the advantage that the empty battery can be replaced by plugging in a charged replacement module.

[0041] From the large spectrum of potential sensor modalities that can be used as elements for a sensor array according to the present invention, the following are preferred: A miniaturized digital pressure sensor SoC is beneficial because it allows for the measurement of blood pressure (a key parameter of cardiac function) at a given location, but in contrast to conventional sensors, does not require a fluid-filled pressurized access channel or an extracorporeal transducer typically used in conventional pressure monitoring catheters, and does not rely on analog signal transmission along the device. A preferred example of a miniaturized digital temperature sensor is beneficial because it allows for the monitoring of body temperature and also makes it possible to measure temperature fluctuations that occur after injecting a bolus of cold fluid, the characteristics and timing of which are related to cardiac performance after such a thermal bolus injection. - Miniaturized digital light emitting elements and receivers for multiple wavelengths make it possible to determine the spectral content of blood and thus obtain blood oxygenation using standard methods, and it is well known that blood oxygenation and the time course of blood oxygenation contain relevant information about cardiopulmonary function. Miniaturized digital vibration sensors allow sensing of dynamic turbulent aspects of blood flow and thereby contribute information to cardiac function. - Ultrasound Doppler sensors allow blood flow velocity to be measured, thereby contributing information to cardiac function. - Direct ultrasonic flow sensors allow for the determination of wave velocity between multiple points, thereby directly measuring blood flow velocity and contributing information about cardiac function. Voltage sensors allow direct detection of the timing and frequency of electrical cardiac activity and allow measurement of local body impedance.

[0042] While the above improvements over the prior art improve patient care, it would be even more desirable to eliminate the need for batteries as the above improvements would simplify manufacturing, improve shelf life, reduce cost, and potentially reduce the risk of battery leakage. Accordingly, further innovations are desirable.

[0043] In a further aspect of the present invention, a device in the form of a medical catheter, sheath, or shaft, comprising a digital sensor SoC arrangement in a portion configured to be located inside the body and wireless transmission electronics in one of the portion configured to be located outside the body and a pluggable module, is further equipped with an energy transfer and power generation mechanism that allows for the elimination of the need for a power source via a battery or cable. A battery-less energy-harvesting medical sensor array is described in combination with the catheter, sheath, and holding shaft. Battery independence can result in a more compact design and improved practicality, as battery drain is no longer an issue.

[0044] Recent advances in wireless technology have made it possible to produce wireless sensors that can be battery powered, thus reducing the need for cables.

[0045] Recent advances in energy harvesting have made it possible to capture energy from environmental sources such as electromagnetic fields, sunlight, vibrations, heat, etc.

[0046] The following energy harvesting mechanisms may be used: a) inductive energy transfer through electromagnetic fields, b) capacitive energy transfer, c) solar cell-based energy transfer, d) vibration energy harvesting, d) thermoelectric energy conversion. The preferred version is inductive energy transfer, as it is typically capable of transferring larger energies compared to other setups, but does not require high voltages on the energy transfer device side.

[0047] Furthermore, the present invention deals with an algorithm for combining vital signals with technical control signals and motor parameters, and discloses a novel combination in which multi-parameter vital signal monitoring as currently known is combined with technical control signals and performance signals coming from catheter-based or implanted circulatory pumps, thus going beyond the state of the art, which has the practical advantage of making vital signal analysis applicable to patients with catheter-based or implanted circulatory assist devices.

[0048] The present invention also features methods for use with multi-parameter signals that are suitable for patients with and without cardiac assist devices.

[0049] One method combines several physiological data sources and several parameters obtained from the cardiac assist device and constructs a nonlinear mathematical model that correlates these data to a target cardiac output value. The physiological data vector includes one or more measurable or obtainable parameters, such as systolic and diastolic pressure, pulse pressure, beat-to-beat interval, mean arterial pressure, maximum slope of pressure rise during systole, area under the systolic portion of the pulse pressure wave, gender (male or female), age, height, weight, and diagnostic class. The parameters obtained from the cardiac assist device include one or more of device blood flow, device type, device performance settings, motor current, rotational frequency, intra-device pressure, and inter-device pressure. Target cardiac output values ​​are obtained across individuals using a variety of methods.

[0050] Multidimensional nonlinear optimization is then used to find a mathematical model that transforms the source data into target CO data. The model is then applied to an individual by obtaining physiological data for the individual and applying the model to the collected data.

[0051] A step consists of adding cardiac assist device parameters in addition to physiological parameters to build a model. In contrast to what was done in the prior art, the present invention uses joint information of biology and assist device to achieve more robust results. While with the setup described in the prior art, the assist device acted as a confounding factor, in the present invention, machine parameters are now a useful source of information. In practice, this expands the patient spectrum to which such monitoring can be applied.

[0052] In another embodiment, measurements of the same biological parameter (preferably blood pressure and its time course) are performed at two different locations within the same circulatory compartment. The advantage of this approach is that pulse wave propagation, a highly nonlinear biological process, can enter the mathematical model as additional information, potentially making the mathematical model more robust. In contrast, ignoring pulse wave propagation, as is commonly done in clinical practice, makes pulse wave propagation a confounding factor for cardiac output analysis.

[0053] The present invention further discloses a monitor designed to enable the above-mentioned cardiac performance determination based on a combination of medical signals and motor control / performance signals, and - A system for monitoring vital signs based on a combination of catheters, sheaths, and shafts equipped with medical sensor SoCs, optional wireless data transmission, optional wireless energy harvesting, and a monitor suitable for multi-mode signals. - Use of systems that combine vital signs and motor parameters for patient monitoring - Use of wireless sensor array data transmission for patient monitoring - Use of energy-harvesting catheters, sheaths, and shafts for patient monitoring - Use of a system combining wireless medical sensor arrays for patient monitoring Also disclosed.

[0054] The medical invasive device according to the invention, used together with the method according to the invention for calculating the cardiac output of a living body, is described in more detail hereinafter by way of an exemplary embodiment and with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0055] [Figure 1] 1 is a cross-sectional view of one embodiment of a medical invasive device according to the present invention. [Figure 2] 1 is a side view of one embodiment of a medical invasive device according to the present invention. [Figure 3] 1A-1C depict an embodiment of a sheath with an integrated flexible electronics substrate and receiver coil circuit, and an embodiment of a shaft with an integrated emitter coil circuit in accordance with the present invention. [Figure 4] 1 is a diagram of one embodiment of a sheath (outer element) covering a segment of a coaxially oriented shaft (inner element) according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0056] Sensor Catheter: In one embodiment of a catheter, sheath, and shaft according to the present invention, a single monitoring catheter is constructed with a polymer molding with an inner lumen of 0.018" (intended for a guidewire) and an outer diameter of 2.8 mm, smaller than the sheaths of current pulmonary artery catheters. Housed in the polymer molding is a flexible electronics board made of polymer with a diameter of 2.4 mm and a length of 15 mm that connects the portion of the device inside the body with the portion outside the body. In the inside part, the flexible board holds two digital sensors in one miniaturized package: a digital pressure sensor and a digital temperature sensor, with integrated analog-to-digital conversion and digital signal transmission packed into a single plastic body measuring 2 x 2 x 0.76 mm (STMicroelectronics, part Nr. LPS22HB). In the outside part, the flexible electronics board holds a connector for wired readout.

[0057] Wireless Sensor Catheter: In one embodiment of the catheter, sheath, and shaft according to the present invention, a single monitoring catheter is constructed with a polymer molding with an inner lumen of 0.018" (intended for a guidewire) and an outer diameter of 2.8 mm, smaller than the sheaths of current pulmonary artery catheters. Housed in the polymer molding is a flexible electronics board made of polymer with a diameter of 2.4 mm and a length of 15 mm, which connects the part of the device inside the body with the part outside the body. In the inside part, the flexible board holds two digital sensors in one miniaturized package: a digital pressure sensor and a digital temperature sensor, with integrated analog-to-digital conversion and digital signal transmission packed into a single plastic body of 2 x 2 x 0.76 mm (STMicroelectronics, part Nr. LPS22HB). In the outside part, the flexible electronics board holds a small chip with digital communication and wireless transmission (TI) and a small battery (type).

[0058] For energy harvesting to be successful, the energy harvested over time must be sufficient to power the sensors for the desired measurement interval (typically ranging between 10 ms and 4 hours) and to power the radio transmissions for the desired transmission interval (typically ranging between 100 ms and 4 hours).

[0059] For inductive wireless powering of devices, an external electromagnetic field needs to be created. Requirements for this electromagnetic field include safety, the ability for sufficient energy transfer, and compatibility with existing regulations. We have identified several design variants as follows:

[0060] 1) A custom-designed energy receiving coil on the catheter, sheath, or shaft and a matched emitter coil with a similar resonant frequency are constructed and optimized so that the received energy is sufficient to drive the electronics integrated into the catheter, sheath, or shaft. An example of such a setup is shown in the Examples. In a preferred setup, such a combination operates within the high-frequency band that legally permits medical use and operates at a distance from the energy emitter to the energy receiver (e.g., 30-50 cm from the catheter insertion site), facilitating bedside applications.

[0061] 2) An emission field is generated near the patient's bed by an emitter. Such energy transmission is well known in the art and is described in detail, for example, in ISO standard 15693, for energy and data transmission up to 1-1.5 meters. The advantage of this solution is that a clinically desirable distance from the patient is maintained, simplifying patient care; the disadvantage of this solution is that the transmitted energy is low, typically allowing only very limited functionality of the electronics on the receiving device.

[0062] 3) The emission field is generated by a transmitter placed close (up to 10 cm) to the device's intraskin exit site. Energy and data transmission is well known in the art and is described in detail in ISO regulation 14443. The advantage of a short distance is improved energy generation at the receiver, thereby allowing more functionality at the device side; the disadvantage is that an emitter coil this distance from the patient can interfere with patient care, and this setup requires that the emitter coil remain close enough over time.

[0063] 4) The emitting field is generated by a transmitter according to a wireless charging standard, e.g., the Qi standard. While the Qi standard was originally designed for high-current charging of devices such as mobile phones in close proximity (a few centimeters) to the emitting coil, we found that an improved setup can be used that allows for the transfer of smaller amounts of energy over larger distances (up to 1 m). Although the amount of energy transferred is much smaller (it decays approximately as the cube of the distance), this is still sufficient for the much lower power electronics used in our setup.

[0064] 5) The emission field is generated by a catheter across a sensor-equipped sheath. This scenario is preferred when using a sensor-equipped sheath to guide the shaft of a circulatory assist device into the body, thus ensuring proximity of the emission coil and the sensor-equipped device and optimizing energy transfer. An example of the operation of this setup is shown below.

[0065] Other standards coming up for wireless interaction regarding the transmission of energy and information, such as the EPC standard, differ in frequency bands, data transmission protocols, and other details, but can be used wherever specific requirements allow it.

[0066] All are optional, but typically higher frequencies ease the design of the emitter and receiver coils as the desired resonant frequency can be achieved with lower inductance coils and smaller capacitors.

[0067] Wireless Energy Transfer / Harvesting: In several experiments, energy harvesting was tested using coils integrated into our catheters, sheaths, and shafts. To this end, a copper wire receiver coil (200 micrometer copper wire, 25 turns, 4 mm coil diameter, 85 mm coil length, inductance of 0.384 microhenries evaluated by resonant tuning) was integrated into the sheath (a polydimethylsiloxane molding). A resonant circuit was created by connecting a 1 nanofarad capacitor in parallel with the receiver coil. Resonance in the receiver circuit was observed at a frequency of 8.12 MHz.

[0068] Additionally, the energy transmitter coil was constructed from 200-micrometer copper wire, 30 turns, a 2-mm coil diameter, and a 150-mm coil length, with a measured inductance of 0.377 microhenries. The transmitter coil was placed inside the shaft of a catheter-based cardiac assist device. A resonant circuit was created by connecting a 1-nanofarad capacitor in parallel with the emitter coil. Resonance of the emitter circuit was observed at the same resonant frequency (8.2 MHz) as the receiver circuit. The shaft was inserted into the sheath so that the emitter coil was coaxial with the receiver coil. The emitter circuit, connected in series with a 100-ohm current-limiting resistor, was driven by a sinusoidal signal at 8.12 MHz and 10 V amplitude generated by a waveform generator (Hewlett-Packard 33120A). The receiver circuit was connected in series with a TS4148 diode, which was used for rectification. The rectified signal was fed to a voltage regulator based on a Texas Instruments LM3671 step-down DC-DC converter.

[0069] Successful energy transfer from the emitter circuit to the receiver circuit was recorded as follows: The voltage across a 1 kilohm resistive load connected to the output of the voltage regulator was 3 V, corresponding to a current of 3 mA and a power of 9 mW. According to the specifications of the pressure and temperature sensor LPS22HB and the Bluetooth Low Energy (LE) IC nrf52832 from Nordic Semiconductor, this power is sufficient for acquiring the pressure and temperature signals and transmitting the acquired data to a remote Bluetooth LE device.

[0070] These results demonstrated that sufficient energy could be transferred to the energy harvester (the catheter holding the sensor).

[0071] Wireless Energy Transfer / Harvesting In one embodiment of a catheter, sheath, or shaft according to the present invention, a copper wire receiver coil (200 micrometer copper wire, 20 turns, 5 mm coil diameter, 4 mm coil length, inductance evaluated by resonant tuning 1.57 microhenries) was incorporated into the sheath (a molding of polydimethylsiloxane). A resonant circuit was created by connecting a 100 picofarad capacitor in parallel with the receiver coil. Resonance in the receiver circuit was observed at a frequency of 12.76 MHz. The emitter coil was separated from the catheter and implemented with 200 micrometer copper wire, 2 turns, 88 mm coil diameter, and 4 mm coil length, and an inductance of 1.56 microhenries was measured. A resonant circuit was created by connecting a 100 picofarad capacitor in parallel with the emitter coil. Resonance in the emitter circuit was observed at 12.75 MHz. The emitter circuit, connected in series with a 1 kilohm current limiting resistor, was driven by a sinusoidal signal generated by a waveform generator (Hewlett-Packard 33120A) at a frequency of 12.76 MHz and an amplitude of 10 V. An SMD1206 red LED was connected in parallel to the receiver circuit. Successful energy transfer from the emitter circuit to the receiver circuit was recorded as follows: When the emitter coil was placed close to the receiver coil (at a distance of 1-3 mm), the LED began to glow, indicating a harvested power utilization of at least several hundred microwatts according to the LED specifications.

[0072] Wireless Energy Harvesting Sensor Catheter: In one embodiment of the catheter, sheath, and shaft according to the present invention, the access sheath for a catheter-based cardiac assist device is constructed from a polymer molding with an inner open lumen of 2.8 mm and an outer diameter of 4 mm, corresponding to the size requirements for the access sheath of the cardiac assist device. Housed within the polymer molding is a flexible polymer electronics board with a diameter of 3 mm and a length of 15 mm, connecting the internal and external portions of the device. In the internal portion, the flexible board holds two digital sensors—a digital pressure sensor and a digital temperature sensor—in a single miniaturized package, with integrated analog-to-digital conversion and digital signal transmission packed into a single plastic body measuring 2 x 2 x 0.76 mm (STMicroelectronics, part number LPS22HB). In the external portion, the flexible electronics board holds a miniaturized chip containing digital communication, wireless transmission, and energy harvesting (TI).

[0073] The present disclosure also includes the following further embodiments.

[0074] Embodiment 1 is an invasive medical device having a main body configured to be inserted into one of a blood vessel, a body cavity, and a body tissue, the invasive medical device being equipped with an electronic circuit and incorporating a sensor device and a digital data transmission device into the main body.

[0075] Embodiment 2 is the medical invasive device according to embodiment 1, which has an analog / digital conversion device in the main body.

[0076] Embodiment 3 is a medical invasive device according to embodiment 1 or embodiment 2, wherein the medical invasive device has an exterior portion configured to be placed outside the body.

[0077] Embodiment 4 is a medical invasive device described in any one of embodiments 1 to 3, wherein the electronic circuit comprises a sensor device having a temperature sensor, a pressure sensor, a vibration sensor, an ultrasonic sensor, an optical sensor, a voltage sensor, or any combination thereof.

[0078] Embodiment 5 is a medical invasive device according to any one of embodiments 1 to 4, wherein the sensor device comprises at least two sensors for measuring different physical signals.

[0079] Embodiment 6 is a medical invasive device according to any one of embodiments 1 to 5, wherein the sensor device comprises at least three sensors for measuring different physical signals.

[0080] Embodiment 7 is a medical invasive device described in any one of embodiments 1 to 6, wherein the medical invasive device has a shaft, which is an elongated object configured to hold the main body portion and traverse the skin level.

[0081] Embodiment 8 is a medical invasive device described in any one of embodiments 1 to 7, wherein the medical invasive device is a catheter, which is an elongated object configured to enter a body and have several fluid columns.

[0082] Embodiment 9 is a medical invasive device described in any one of embodiments 1 to 8, wherein the medical invasive device is a sheath, which is an elongated object configured to guide one of a catheter, a shaft of a treatment device, and a shaft of a heart pump.

[0083] Embodiment 10 is a medical invasive device according to any one of embodiments 1 to 9, wherein the body portion has a cross-sectional area of ​​less than 60 square millimeters.

[0084] Embodiment 11 is a medical invasive device described in any one of embodiments 1 to 10, wherein the main body portion has a cross-sectional area of ​​less than 20 square millimeters.

[0085] Embodiment 12 is a medical invasive device described in any one of embodiments 1 to 11, wherein the main body portion has a cross-sectional area of ​​less than 5 square millimeters.

[0086] Embodiment 13 is a medical invasive device described in any one of embodiments 1 to 12, wherein the electronic circuit comprises a wireless data transmission unit.

[0087] Embodiment 14 is a medical invasive device according to any one of embodiments 3 to 13, wherein the outer part comprises a wireless data transmission unit.

[0088] Embodiment 15 is a medical invasive device described in embodiment 14, wherein the wireless data transmission unit is detachable from the base of the outer portion.

[0089] Embodiment 16 is a medical invasive device according to any one of embodiments 1 to 15, powered by one of a battery and a capacitor.

[0090] Embodiment 17 is a medical invasive device described in any one of embodiments 3 to 16, wherein the battery or capacitor is removable from the outer portion.

[0091] Embodiment 18 is a medical invasive device described in any one of embodiments 1 to 17, wherein the electronic circuit comprises a power generation unit configured to obtain energy from an energy source that is not connected to the medical invasive device by an electrical wire.

[0092] Embodiment 19 is a medical invasive device according to any one of embodiments 3 to 18, wherein the outer part holds a power generating unit.

[0093] Embodiment 20 is a medical invasive device according to embodiment 19, wherein the power generating unit comprises a coil for harvesting electromagnetic energy.

[0094] Embodiment 21 is a medical invasive device according to embodiment 19 or 20, wherein the power generating unit comprises a solar cell.

[0095] Embodiment 22 is a medical invasive device according to any one of embodiments 18 to 21, wherein the power generating unit comprises a vibration-based power generator.

[0096] Embodiment 23 is a medical invasive device according to any one of embodiments 18 to 22, wherein the power generating unit comprises a thermoelectric generator.

[0097] Embodiment 24 is a medical invasive device described in any one of embodiments 1 to 23, comprising a power generating unit having a receiving coil circuit that is tuned to a frequency such that an electromagnetic field generated in proximity typically induces energy transfer to the coil that is sufficient to drive the electronic circuitry in the main body and optionally any other electronic circuitry of the medical invasive device.

[0098] Embodiment 25 is a medical invasive device according to any one of embodiments 1 to 24, comprising a power generation unit having a receiving coil circuit configured to harvest energy from an electromagnetic field, the field being generated by several emitting coil circuits, the emitting coil circuits having a resonant frequency within 10% of the resonant frequency of the receiving coil circuit, preferably within 1% of the resonant frequency of the receiving coil circuit, particularly preferably within 0.1% of the resonant frequency of the receiving coil circuit.

[0099] Embodiment 26 is a medical invasive device described in any one of embodiments 1 to 25, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 5.725 to 5.875 GHz.

[0100] Embodiment 27 is a medical invasive device described in any one of embodiments 1 to 26, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 2.4 to 2.5 GHz.

[0101] Embodiment 28 is a medical invasive device described in any one of embodiments 1 to 27, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 902 to 928 MHz.

[0102] Embodiment 29 is a medical invasive device described in any one of embodiments 1 to 28, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 13.553 to 13.567 MHz.

[0103] Embodiment 30 is a medical invasive device described in any one of embodiments 1 to 29, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 6.765 to 6.795 MHz.

[0104] Embodiment 31 is a medical invasive device described in any one of embodiments 1 to 30, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 235 to 275 kHz (a band defined by the Power Matters Alliance (PMA)).

[0105] Embodiment 32 is a medical invasive device described in any one of embodiments 1 to 31, comprising several coil circuits configured to harvest energy from electromagnetic fields in a frequency band ranging from 110 to 205 kHz (a band defined by the Wireless Power Consortium (WPC)).

[0106] Embodiment 33 is a kit comprising an outer element which is a sheath described in any one of embodiments 9 to 32 and an inner element which is a shaft or catheter having a coil circuit, wherein the outer element covers at least one segment of the inner element.

[0107] Embodiment 34 is the kit of embodiment 33, wherein the inner element is configured to be coaxially oriented relative to the outer element.

[0108] Embodiment 35 is a kit described in embodiment 33 or 34, wherein the inner coil is configured to transmit energy to the outer element.

[0109] Embodiment 36 is a kit described in embodiment 35, wherein the inner coil is configured to receive data from the outer element by wireless transmission.

[0110] Embodiment 37 is a kit described in any one of embodiments 33 to 36, wherein the outer coil is configured to receive data from the inner element by wireless transmission.

[0111] Embodiment 38 is a kit according to any one of embodiments 33 to 37, wherein the inner element is the shaft of a percutaneous heart pump.

[0112] Embodiment 39 is a method for calculating cardiac output (CO) of a living organism, in which a mathematical model is constructed linking input data vectors and target CO values.

[0113] Embodiment 40 is the method of embodiment 39, wherein the mathematical model is nonlinear.

[0114] Embodiment 41 is a method described in embodiment 39 or 40, wherein the input data vector comprises at least one sensor measurement value acquired by a medical invasive device described in any one of embodiments 1 to 32.

[0115] Embodiment 42 is the method according to any one of embodiments 39 to 41, wherein the input data vector comprises physiological input source data from the living body.

[0116] Embodiment 43 is the method of any one of embodiments 39 to 42, wherein the input data vector comprises an area under the curve of repeated temperature measurements.

[0117] Embodiment 44 is a method according to any one of embodiments 39 to 43, wherein the input data vector comprises the area under the curve of repeated temperature measurements after a bolus of fluid is injected into the venous circulation, the injected bolus having a temperature different from the blood temperature.

[0118] Embodiment 45 is the method of any one of embodiments 39 to 44, wherein the input data vector comprises numerical values ​​obtained from an arterial pulse pressure analysis.

[0119] Embodiment 46 is a method described in any one of embodiments 39 to 45, wherein the input data vector includes numerical values ​​obtained from arterial pulse pressure analysis, the numerical values ​​being one of the following: heart beat interval, heart rate, systolic blood pressure, diastolic blood pressure, pulse pressure, peak systolic pressure difference per time difference, area under the pulse curve, and area under the systolic portion of the pulse pressure wave.

[0120] Embodiment 47 is a method described in any one of embodiments 39 to 46, wherein the input data vector includes at least one of the systolic pressure of the living body, the diastolic pressure of the living body, and the pulse pressure of the living body.

[0121] Embodiment 48 is a method described in any one of embodiments 39 to 47, wherein the input data vector includes at least one of the age of the organism, the sex of the organism, the height of the organism, the weight of the organism, and the temperature of the organism.

[0122] Embodiment 49 is a method described in any one of embodiments 39 to 48, wherein the input data vector includes at least one of the type of heart pump, the performance setting of the heart pump, the size of the heart pump, the blood flow rate of the heart pump, the rotational speed of the heart pump, the power consumption of the heart pump, the current consumption of the heart pump, and the pressure sensor reading of the heart pump.

[0123] Embodiment 50 is the method of any one of embodiments 39 to 49, wherein the target CO value is determined by an algorithm comprising determining an area under a curve of repeated temperature measurements at multiple time points.

[0124] Embodiment 51 is the method of any one of embodiments 39 to 50, wherein the target CO value is determined by analysis of a physiological signal measured by a medical invasive device of any one of embodiments 1 to 32.

[0125] Embodiment 52 is the method of any one of embodiments 39 to 51, wherein generating the mathematical model comprises fitting the input data vector to the target CO value in a least-squares optimal manner.

[0126] Embodiment 53 is a method according to any one of embodiments 39 to 52, wherein the step of generating the mathematical model includes training an artificial neural network (ANN).

[0127] Embodiment 54 is a method described in any one of embodiments 39 to 53, wherein the step of generating the mathematical model includes unsupervised learning of a deep neural network (DNN).

[0128] Embodiment 55 is a method described in any one of embodiments 39 to 53, wherein the step of generating the mathematical model includes supervised learning of a deep neural network (DNN).

[0129] Embodiment 56 is a method according to any one of embodiments 39 to 55, wherein the step of generating the mathematical model includes training a deep believe network (DBN).

[0130] Embodiment 57 is a method according to any one of embodiments 39 to 56, comprising the steps of obtaining an input data vector, transforming the input data vector using at least the mathematical model, and expressing the result of the transformation as a CO value in physiological units.

[0131] Embodiment 58 is a method according to any one of embodiments 39 to 57, comprising the steps of obtaining a plurality of the target CO values, generating the mathematical model based at least in part on the target CO values, obtaining an input data vector, transforming the input data vector using at least the mathematical model, and expressing the results of the transformation as CO values ​​in physiological units.

[0132] Embodiment 59 is an apparatus comprising an apparatus for receiving data transmitted by a medical invasive device described in any one of embodiments 1 to 32.

[0133] Embodiment 60 is the apparatus described in embodiment 59, wherein data is transmitted wirelessly by the medical invasive device.

[0134] Embodiment 61 is the device described in embodiment 59 or 60, comprising an apparatus for receiving data transmitted from a second device and used to derive the input data vector.

[0135] Embodiment 62 is an apparatus described in embodiment 61, wherein the second apparatus is a medical monitor defined as a device configured to be placed in the same room as the patient and having a display configured to display the patient's vital signs.

[0136] Embodiment 63 is the device described in embodiment 61 or 62, wherein the second device is the control device of a heart pump.

[0137] Embodiment 64 is an apparatus described in any one of embodiments 61 to 63, comprising a device for receiving data wirelessly transmitted from the second device and used to derive the input data vector.

[0138] Embodiment 65 is an apparatus described in any one of embodiments 60 to 64, wherein the wireless data transmission complies with one of the WiFi standard, the Bluetooth standard, and the Ant standard.

[0139] Embodiment 66 is a computer program comprising a code structure configured to perform the method according to any one of embodiments 39 to 58 when executed on a computer.

[0140] Embodiment 67 is an apparatus described in any one of embodiments 59 to 65, comprising the computer program described in embodiment 66.

[0141] Embodiment 68 is a device described in any one of embodiments 59 to 65 and embodiment 67, comprising a display configured to display at least cardiac output (CO).

[0142] Embodiment 69 is a computer program according to embodiment 66, stored on a computer-readable medium.

[0143] Embodiment 70 is a computer program product stored on a machine-readable carrier comprising program code means for performing the method according to any one of embodiments 39 to 58 when the program is executed on a computer.

Claims

1. An apparatus comprising a medical invasive device and a control device for a cardiac pump, the apparatus comprising: an apparatus for receiving data transmitted by the medically invasive device, the medically invasive device having a body configured to be inserted into one of a blood vessel, a body cavity, and a body tissue, the apparatus being equipped with electronic circuitry and incorporating a sensor device and a digital data transmission device in the body; an apparatus for receiving data transmitted from a control device of the cardiac pump, wherein the data transmitted by the medical invasive device and the data transmitted from the control device of the cardiac pump are used to derive an input data vector for calculating cardiac output (CO) of the living body; Further equipped with the equipment.

2. The apparatus of claim 1 , wherein data is transmitted wirelessly by the medical invasive device.

3. 3. The apparatus of claim 1, wherein the control device of the heart pump is a medical monitor, defined as a device configured to be placed in the same room as a patient, and comprising a display configured to display the patient's vital signs.

4. 4. An apparatus according to claim 1, further comprising a device for receiving data transmitted wirelessly from a control device of the heart pump and used to derive the input data vector.

5. 5. The device according to claim 2 or 4, wherein the wireless data transmission complies with one of the following standards: the Wi-Fi standard, the Bluetooth standard of the IEEE 802.15.1 standard, and the Ant standard.

6. 6. The apparatus according to any one of claims 1 to 5, comprising a computer program with a code structure configured to perform, when executed on a computer, a method for calculating the cardiac output (CO) of an organism, wherein a mathematical model is constructed linking input data vectors and target CO values.

7. 6. The apparatus of claim 1, further comprising a display configured to display at least the cardiac output (CO) of the living body.

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