# US 12,213,771 B2 · Thermistor imbedded therapeutic catheter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,213,771 B2 - Document ID: US12213771B2 - Status: Granted - Kind: B2 - Application number: 17/673,255 - Filed: 2022-02-16 - Published: 2022-09-01 - Granted: 2025-02-04 - Earliest claimed: 2017-03-21 - Assignees: ABIOMED, Inc.; Icahn School of Medicine at Mount Sinai - Applicants: ABIOMED, Inc.; Icahn School of Medicine at Mount Sinai - Inventors: Jerald Wayne Curran; Kiyotake Ishikawa; Roger J. Hajjar - Web page: https://patentgrep.com/patent/US12213771B2 ## CPC - A61B 5/029: Measuring blood output from the heart, e.g. minute volume - A61B 5/02028: {Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction} - A61B 5/02141: {Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits (A61B5/02233, A61B5/0235 take precedence)} - A61B 5/0215: by means inserted into the body - A61B 5/028: by thermo-dilution - A61B 5/6852: {Catheters} - A61M 60/13: by means of a catheter allowing explantation, e.g. catheter pumps temporarily introduced via the vascular system - A61M 60/135: inside a blood vessel, e.g. using grafting - A61M 60/148: in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices - A61M 60/205: Non-positive displacement blood pumps - A61M 60/216: including a rotating member acting on the blood, e.g. impeller - A61M 60/50: Details relating to control - A61M 60/515: Regulation using real-time patient data - A61M 60/531: using blood pressure data, e.g. from blood pressure sensors - A61M 60/538: Regulation using real-time blood pump operational parameter data, e.g. motor current - A61M 60/585: User interfaces - A61M 60/816: Sensors arranged on or in the housing, e.g. ultrasonic flow sensors - A61M 60/00: Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance (heart stimulation A61H31/00; heart stimulators for electrotherapy A61N1/362) - 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 A system and method for determining native cardiac output of a heart while maintaining operation of an intracardiac blood pump includes determining a current drawn by the pump motor, a blood pressure within the ascending aorta, and a change in the blood temperature based on a thermodilution technique. An intracardiac blood pump positioned in the aorta includes at least one sensor for determining a motor current and blood pressure and a thermistor for determining the change in blood temperature after a precise fluid bolus has been introduced into the vasculature. A processor receives current, pressure, and temperature measurements, and calculates a pump flow output and a total cardiac output from which the native cardiac output is calculated. The native cardiac output and other clinically relevant variables derived from the measurements inform decisions related to continued therapeutic care, including increasing or decreasing cardiac assistance provided by the intracardiac pump. ## Claims ### Claim 1 A system for measuring performance of a beating heart of a patient, comprising: an intracardiac blood pump having a cannula with proximal and distal openings, a surface disposed between the proximal and distal openings and being configured to be positioned in an aorta of a patient; an electrically driven motor and an electrical line configured to supply current to the motor to cause the intracardiac blood pump to pump blood through the cannula when the intracardiac blood pump is positioned in the aorta of the patient; a catheter having proximal and distal end regions, the distal end region being connected to the cannula; a thermistor that is configured to detect blood temperature of the blood flowing in the heart's ascending aorta when the intracardiac blood pump is positioned in the aorta of the patient; a first sensor configured to detect changes in the motor current during operation of the intracardiac blood pump; a second sensor configured to detect blood pressure within the ascending aorta when the intracardiac blood pump is positioned in the aorta of the patient; and a processor configured to: receive a first signal from the first sensor, the first signal being indicative of a change in the motor current, receive a second signal from the second sensor, the second signal being indicative of the blood pressure within the ascending aorta, and receive a third signal from the thermistor indicative of a temperature of blood flowing in the heart's ascending aorta, calculate a pump flow output based on the first signal and the second signal, wherein the pump flow output is indicative of a cardiac assistance provided by the intracardiac blood pump; calculate a total cardiac output based on the third signal, wherein the total cardiac output comprises (a) the cardiac assistance provided by the intracardiac blood pump and (b) a native cardiac output of the beating heart, and calculate the native cardiac output of the beating heart based on the pump flow output and the total cardiac output. ### Claim 2 (depends on 1) The system of claim 1, wherein the third signal indicates a change in temperature of blood flowing into the heart caused by a bolus of fluid introduced into vasculature of the patient at a location that is upstream from the intracardiac blood pump, wherein the introduced bolus of fluid is at an initial temperature that is different than a physiologic blood temperature. ### Claim 3 (depends on 1) The system of claim 1, wherein the third signal indicates a change in temperature of blood flowing near or through the proximal opening of the cannula. ### Claim 4 (depends on 1) The system of claim 1, wherein the processor is configured to determine the total cardiac output by detecting changes in the third signal as a function of time. ### Claim 5 (depends on 1) The system of claim 1, wherein the native cardiac output is calculated by subtracting the pump flow output from the total cardiac output. ### Claim 6 (depends on 1) The system of claim 1, wherein the thermistor is disposed on the distal end region of the catheter. ### Claim 7 (depends on 1) The system of claim 1, further comprising a second thermistor disposed on the intracardiac blood pump proximal of the proximal openings of the cannula, the second thermistor configured to detect blood temperature near the catheter. ### Claim 8 (depends on 1) The system of claim 1, wherein the processor is further configured to calculate from the first, second, and third signals at least one of a global end-diastolic volume, an intrathoracic blood volume, an intrathoracic thermal volume, a pulmonary thermal volume, a cardiac index, a stroke volume, an extravascular lung water, a cardiac power output, and a global ejection fraction. ### Claim 9 (depends on 1) The system of claim 1, wherein the processor is further configured to display the native cardiac output on a screen. ### Claim 10 (depends on 1) The system of claim 1, wherein the processor is further configured to record and store the native cardiac output and to display a history of the native cardiac output as a function of time. ### Claim 11 (depends on 10) The system of claim 10, wherein the processor is further configured to determine a native trend based on the history of the native cardiac output, wherein the native trend indicates whether the native cardiac output is improving with time. ### Claim 12 (depends on 11) The system of claim 11, wherein the processor is further configured to display the native trend on a display. ### Claim 13 (depends on 1) The system of claim 1, wherein the processor is configured to calculate the pump flow output by accessing a lookup table that provides a flow rate that is the pump flow output for a given motor current and detected pressure. ### Claim 14 (depends on 1) The system of claim 1, wherein the thermistor is positioned proximal to a proximal end of the intracardiac blood pump. ### Claim 15 (depends on 1) The system of claim 1, wherein the thermistor is imbedded in the catheter. ### Claim 16 (depends on 1) The system of claim 1, further comprising a sheath for delivering the intracardiac blood pump to the patient's heart. ### Claim 17 (depends on 16) The system of claim 16, wherein the thermistor is imbedded in the sheath. ### Claim 18 (depends on 16) The system of claim 16, wherein the sheath comprises a first lumen and a second lumen, the first lumen is sized for delivery of the intracardiac blood pump and the second lumen is sized for delivery of the thermistor. ### Claim 19 (depends on 1) The system of claim 1, further comprising a rotor disposed within the cannula. ### Claim 20 A method for measuring performance of a beating heart of a patient, the method comprising: positioning an intracardiac blood pump in the patient's aorta and driving the intracardiac blood pump with a motor current to cause a motor of the intracardiac blood pump to pump blood from the patient's left ventricle and into the patient's ascending aorta; detecting, by a thermistor, a change in temperature of blood being pumped from the left ventricle into the ascending aorta; detecting, by a first sensor, a change in motor current during operation of the intracardiac blood pump; detecting, by a second sensor, a pressure within the ascending aorta; calculating, by a processor, a total cardiac output based on the detected temperature change wherein the total cardiac output comprises (a) a cardiac assistance provided by the intracardiac blood pump and (b) a native cardiac output of the beating heart; calculating, by the processor, a pump flow output based on the detected change in motor current by the first sensor and the detected pressure by the second sensor, wherein the calculated pump flow output is indicative of the cardiac assistance provided by the intracardiac blood pump; and calculating, by the processor, the native cardiac output of the beating heart based on the pump flow output and the total cardiac output.