# US 12,178,554 B2 · Systems and methods for determining a viscosity of a fluid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,178,554 B2 - Document ID: US12178554B2 - Status: Granted - Kind: B2 - Application number: 15/734,519 - Filed: 2019-06-06 - Published: 2022-02-17 - Granted: 2024-12-31 - Earliest claimed: 2018-06-06 - Assignees: Kardion GmbH - Applicants: Kardion GmbH - Inventors: Ingo Stotz; Thomas Alexander Schlebusch - Web page: https://patentgrep.com/patent/US12178554B2 ## CPC - A61B 5/02035: {Determining blood viscosity} - A61B 5/0215: by means inserted into the body - A61B 5/7246: {using correlation, e.g. template matching or determination of similarity} - A61B 8/488: {involving Doppler signals} - A61M 60/178: drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices - A61M 60/216: including a rotating member acting on the blood, e.g. impeller - A61M 60/403: for non-positive displacement blood pumps - A61M 60/523: using blood flow data, e.g. from blood flow transducers - A61M 60/531: using blood pressure data, e.g. from blood pressure sensors - A61M 60/148: in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices - A61M 2205/3331: Pressure; Flow - A61M 2205/3334: Measuring or controlling the flow rate - A61M 2205/3344: Measuring or controlling pressure at the body treatment site - A61M 2205/3365: Rotational speed - A61M 2205/3375: Acoustical, e.g. ultrasonic, measuring means - A61M 2205/3379: Masses, volumes, levels of fluids in reservoirs, flow rates - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract The approach presented here relates to a determination appliance (100) for determining a viscosity of a fluid. The determination appliance (100) has at least one determination device (110) and a provisioning device (115). The determination device (110) is designed to determine the viscosity of the fluid and/or a rotational speed (ω) of a blade wheel (205) for conveying the fluid by using at least one detected volume flow of the fluid and a detected pressure difference of the fluid. The provisioning device (115) is designed to provide or send a viscosity signal (130) representing the viscosity determined by the determination device (110). ## Claims ### Claim 1 A ventricular assist system comprising: an impeller; a drive device coupled to the impeller, the drive device configured to drive the impeller at a rotational speed (ω); a pressure sensor device; and a determination device comprising: a cannula configured to be implanted in a body of a patient, wherein the cannula comprises: a lateral receiving interface distal to the impeller, configured to receive blood of the patient into an interior of the cannula; and an outlet interface, wherein the impeller is configured to convey the blood from the lateral receiving interface to the outlet interface; and a volumetric flow sensor positioned at a tip of the cannula distal to the impeller and configured to sense a volumetric flow (Q) of the blood of the patient through the cannula, the volumetric flow sensor comprising a Doppler ultrasonic sensor; wherein the pressure sensor device is configured to sense a pressure difference (Δp) of the blood in a region of the receiving interface and a region of the outlet interface, and wherein the determination device is configured to determine viscosity (η) of blood in the body of the patient based on at least the sensed volumetric flow (Q) of the blood, the sensed pressure difference (Δp) of the blood, and either the rotational speed (ω) of the impeller or an electric power input Pel of a drive device for the impeller. ### Claim 2 (depends on 1) The ventricular assist system of claim 1, wherein the determination device is configured to determine the viscosity (η) based on a functional relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η). ### Claim 3 (depends on 1) The ventricular assist system of claim 1, wherein the determination device is configured to determine the viscosity (η) using a lookup table. ### Claim 4 (depends on 3) The ventricular assist system of claim 3, wherein a relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η) is stored in the lookup table. ### Claim 5 (depends on 1) The ventricular assist system of claim 1, wherein the impeller is positioned in a region of the outlet interface. ### Claim 6 (depends on 1) The ventricular assist system of claim 1, wherein the pressure sensor device comprises at least one differential pressure sensor or two barometric pressure sensors, wherein the at least one differential pressure sensor or two barometric pressure sensors are configured to measure the pressure difference (Δp) between two sensor points. ### Claim 7 (depends on 1) The ventricular assist system of claim 1, wherein the pressure sensor device is configured to sense the pressure difference (Δp) between two sensor points. ### Claim 8 A method for determining a viscosity (η) of blood of a patient in a ventricular assist system, comprising: sensing a volumetric flow (Q) using a volumetric flow sensor of a determination device of the ventricular assist system, the volumetric flow sensor comprising a Doppler ultrasonic sensor arranged in a distal tip of a cannula of the determination device, the cannula, configured to be implanted in a body of the patient, wherein the ventricular assist system comprises: an impeller configured to convey blood from a lateral receiving interface of the cannula distal to the impeller to an outlet interface of the cannula; and a drive device coupled to the impeller, the drive device configured to drive the impeller at a rotational speed (ω); sensing a pressure difference (Δp) of blood in a region of the receiving interface and the outlet interface; and determining the viscosity (η) of the blood based on at least the sensed volumetric flow (Q) of the blood, the sensed pressure difference (Δp) of the blood, and either the rotational speed (ω) of the impeller or an electric power input Pel of a drive device for the impeller. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the viscosity (η) comprises determining the viscosity (η) based on a functional relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η). ### Claim 10 (depends on 8) The method of claim 8, wherein determining the viscosity (η) comprises using a lookup table. ### Claim 11 (depends on 10) The method of claim 10, wherein a relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η) is stored in the lookup table. ### Claim 12 (depends on 8) The method of claim 8, wherein the impeller is positioned in a region of the outlet interface. ### Claim 13 (depends on 8) The method of claim 8, wherein the pressure sensor device comprises at least one differential pressure sensor or two barometric pressure sensors. ### Claim 14 (depends on 8) The method of claim 8, wherein the pressure sensor device is configured to sense a pressure difference (Δp) between two sensor points. ### Claim 15 A non-transitory computer-readable storage medium comprising instructions that, when executed, direct a processor to perform a method comprising: sensing a volumetric flow (Q) using a volumetric flow sensor of a determination device of a ventricular assist system, the volumetric flow sensor comprising a Doppler ultrasonic sensor arranged in a distal tip of a cannula of the determination device, the cannula, configured to be implanted in a body of a patient, wherein the ventricular assist system comprises: an impeller configured to convey blood from a lateral receiving interface of the cannula that is distal to the impeller to an outlet interface of the cannula; and a drive device coupled to the impeller, the drive device configured to drive the impeller at a rotational speed (ω); sensing a pressure difference (Δp) of blood in a region of the receiving interface and the outlet interface; and determining a viscosity (η) of the blood based on at least the sensed volumetric flow (Q) of the blood, the sensed pressure difference (Δp) of the blood, and either the rotational speed (co) of the impeller or an electric power input Pel of a drive device for the impeller. ### Claim 16 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein determining the viscosity (η) comprises determining the viscosity (η) based on a functional relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η). ### Claim 17 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein determining the viscosity (η) comprises using a lookup table. ### Claim 18 (depends on 17) The non-transitory computer-readable storage medium of claim 17, wherein a relationship between the volumetric flow (Q), the pressure difference (Δp), and the viscosity (η) is stored in the lookup table.