# US 2019/0167188 A1 · Systems and Methods for Patient Fluid Management > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0167188 A1 - Document ID: US20190167188A1 - Status: Published application - Kind: A1 - Application number: 16/271,798 - Filed: 2019-02-09 - Published: 2019-06-06 - Earliest claimed: 2016-08-11 - Assignees: Foundry Innovation & Research 1, Ltd. - Applicants: Foundry Innovation & Research 1, Ltd. - Inventors: Hanson S. Gifford, III; Mark E. Deem; Conor M. Hanley; Fiachra M. Sweeney; Jeffry J. Grainger; John R. Britton; Annette Kent - Web page: https://patentgrep.com/patent/US20190167188A1 ## CPC - A61B 5/1076: {for measuring dimensions inside body cavities, e.g. using catheters (A61B3/1005 takes precedence)} - A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition - A61B 5/076: {Permanent implantation} - A61B 5/4836: {Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence)} - A61B 5/4839: {combined with drug delivery} - A61B 5/4875: {Hydration status, fluid retention of the body} - A61B 5/6876: {Blood vessel} - A61B 5/746: {Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms} - A61B 8/06: Measuring blood flow - A61B 8/0891: {for diagnosis of blood vessels} - A61B 8/12: in body cavities or body tracts, e.g. by using catheters - A61B 8/5223: {for extracting a diagnostic or physiological parameter from medical diagnostic data (for algorithms to analyse biomedical images G06T7/0012)} - A61B 8/5292: {using additional data, e.g. patient information, image labeling, acquisition parameters} - A61B 8/56: {Details of data transmission or power supply} - G16H 50/30: for calculating health indices; for individual health risk assessment - A61B 5/021: Measuring pressure in heart or blood vessels - A61B 5/0215: by means inserted into the body - A61B 5/024: Measuring pulse rate or heart rate - A61B 5/6882: {Anchoring means} - A61B 8/4472: {Wireless probes} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA ## Abstract Systems and methods are disclosed that provide for regular, periodic or continuous monitoring of fluid volume based on direct measurement of an inferior vena cava (IVC) physical dimension using a wireless measurement sensor implanted in the IVC. By basing diagnostic decisions and treatments on changes in an IVC physical dimension, information on patient fluid state is available across the entire euvolemic range of fluid states, thus providing earlier warning of hypervolemia or hypovolemia and enabling the modulation of patient treatments to permit more stable long-term fluid management. ## Claims ### Claim 1 A method of managing patient body fluid volume, comprising: directly measuring a physical dimension of the patient's IVC with a sensing device implanted within the IVC; wirelessly communicating with the implanted sensing device to monitor changes in the measured IVC dimension within an euvolemic region defined for said patient; and generating an alert signal when IVC metrics based at least in part on the measured IVC physical dimension indicate the patient's fluid volume state meets predetermined clinical limits for the defined euvolemic region. ### Claim 2 (depends on 1) The method of claim 1, wherein said physical dimension of the patient's IVC is at least one of IVC diameter or IVC area. ### Claim 3 (depends on 1) The method of claim 1, further comprising positioning and anchoring the sensing device within the patient's IVC, the sensing device configured to measure at least one of IVC diameter or IVC area. ### Claim 4 (depends on 1) The method of claim 1, further comprising receiving said alert signal at a patient therapy device and automatedly initiating a patient therapy via said therapy device in response to receiving said alert signal. ### Claim 5 (depends on 1) The method of claim 1, further comprising setting said predetermined clinical limits for the patient, wherein: said predetermined clinical limits comprise at least an indication of the patient fluid state trending towards hypovolemia, and an indication of the patient fluid state trending towards hypervolemia; and each of said predetermined limits falls within the euvolemic range defined for the patient. ### Claim 6 (depends on 5) The method of claim 5, wherein said setting said predetermined clinical limits comprises setting (1) a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent a hypovolemic region and (2) a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent a hypervolemic region, wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC physical dimension measurements for said patient. ### Claim 7 (depends on 6) The method of claim 6, wherein the euvolemic range corresponds to a range of measured IVC diameters between about 14 mm and about 21 mm. ### Claim 8 (depends on 6) The method of claim 6, wherein the alert signal is generated when said IVC metrics indicate the patient fluid state falls within either of the hypovolemic warning zone or the hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 9 (depends on 8) The method of claim 8, further comprising initiating fluid intervention to correct body fluid volume in response to said alert signal while patient fluid volume is within one of said hypovolemic warning zone of the euvolemic region or said hypervolemic warning zone of the euvolemic region. ### Claim 10 (depends on 9) The method of claim 9, wherein said alert signal comprises a hypovolemia alert generated in response to the IVC metrics indicating the patient fluid state falls within the hypovolemic warning zone and, in response to said hypovolemia alert, said intervention comprises at least one of administration of fluids or vasoconstricting drugs. ### Claim 11 (depends on 9) The method of claim 9, wherein said alert signal comprises a hypervolemia alert generated in response to the IVC metrics indicating the patient fluid state falls within the hypervolemic warning zone and, in response to said hypervolemia alert, said intervention comprises at least one of dialysis or administration of diuretics or vasodilating drugs. ### Claim 12 (depends on 1) The method of claim 1, wherein said steps of measuring and wirelessly communicating with the sensor implant are performed with the patient located outside of a healthcare facility. ### Claim 13 (depends on 1) The method of claim 1, wherein said IVC metrics are determine based on a combination of measured and calculated data including at least a measured IVC physical dimension and calculated collapsibility index. ### Claim 14 (depends on 13) The method of claim 13, further comprising: determining patient fluid volume state based on said combination of measured and calculated data; and said generating an alert signal comprises generating a patient level alert when patient fluid volume status is determined to fall within a first range, and generating a clinical level alert when patient fluid volume status is determined to fall within a second range. ### Claim 15 (depends on 14) The method of claim 14, wherein: said patient level alert is transmitted to a patient device and prompts the patient to begin a self-directed treatment; and said clinical level alert is transmitted to a healthcare provider device and prompts a healthcare provider to review patient fluid volume state information transmitted to the healthcare provider device. ### Claim 16 (depends on 1) The method of claim 1, wherein said communicating and generating are controlled by a processor executing instructions stored in a memory, and further comprising executing instructions stored in memory comprising instructions for: defining euvolemic, hypovolemic and hypervolemic regions for said patient wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC diameter or volume measurements for the patient; identifying a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent the hypovolemic region; identifying a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent the hypervolemic region; and generating said alert signal when measured IVC diameter or volume falls within either of the hypovolemic warning zone or hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 17 A method of managing patient body fluid volume, comprising: wirelessly receiving, from a sensor implanted in the patient's IVC, signals representing changes in a physical dimension of the patient's IVC; processing the received signals to provide IVC metrics representative of patient fluid volume state throughout an euvolemic region defined for the patient, said IVC metrics including at least one of IVC collapsibility index (CI), IVC diameter, IVC area, and a magnitude of IVC collapse over a selected period; comparing said IVC metrics to predetermined values associated with a plurality of patient fluid volume states to determine a current patient fluid state; and generating an alert signal when the determined patient fluid state meets predetermined clinical limits for the patient. ### Claim 18 (depends on 17) The method of claim 17, further comprising setting said determined clinical limits for the patient, wherein: said predetermined clinical limits comprise at least an indication of the patient fluid state trending towards hypovolemia, and an indication of the patient fluid state trending towards hypervolemia; and each of said predetermined limits falls within a euvolemic range defined for the patient. ### Claim 19 (depends on 18) The method of claim 18, wherein said setting said predetermined clinical limits comprises setting (1) a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent a hypovolemic region and (2) a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent a hypervolemic region, wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC physical dimension measurements for said patient. ### Claim 20 (depends on 19) The method of claim 19, further comprising generating a prompt to initiate a fluid intervention to correct body fluid volume in response to said alert signal while patient fluid volume falls within one of said hypovolemic warning zone of the euvolemic region or said hypervolemic warning zone of the euvolemic region. ### Claim 21 (depends on 17) The method of claim 17, wherein said receiving, processing, comparing and generating are controlled by a processor executing instructions stored in a memory, and further comprising executing instructions stored in memory comprising instructions for: defining euvolemic, hypovolemic and hypervolemic regions for said patient wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC diameter or volume measurements for the patient; determining said clinical limits by identifying a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent the hypovolemic region, and identifying a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent the hypervolemic region; and generating said alert signal when measured IVC diameter or volume falls within either of the hypovolemic warning zone or hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 22 A diagnostic method for monitoring patient body fluid volume, comprising: positioning a sensing device within the patient's IVC, the sensing device configured to measure at least one physical dimension of the IVC; wirelessly monitoring changes in measured IVC physical dimension over time within an euvolemic region defined for said patient; identifying (1) a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent a hypovolemic region and (2) a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent a hypervolemic region, wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC physical dimension measurements for said patient; and signaling a warning state when measured IVC physical dimension falls within either of the hypovolemic warning zone or hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 23 A system for managing patient body fluid volume, comprising: a wireless sensing device implantable within the patient's IVC for directly measuring a physical dimension of the patient's IVC; and a control system configured to wirelessly receive a measurement signal from the sensing device indicative of the measured physical dimension and derive data from the measurement signal indicative of a fluid volume state of the patient, the control system being further configured to generate an alert signal when IVC metrics based at least in part on the measured IVC physical dimension indicate the patient's fluid volume state meets predetermined clinical limits for a euvolemic region defined for said patient. ### Claim 24 (depends on 23) The system of claim 23, wherein the control system comprises: a sensing device control module configured to wirelessly communicate with said wireless sensing device when implanted in the IVC to at least receive said measurement signal; and a patient management system comprising a processor and memory, the patient management system configured to receive or generate measurement data representative of said measured IVC physical dimension based on said measurement signal, to receive patient specific information, and to execute instructions contained in the memory responsive to received patient specific information and said measurement data, said instructions comprising instructions to— prompt for initiation of a measurement of the IVC physical dimension; determine IVC metrics based at least in part on data representative of said measured IVC physical dimension; and generate an alert signal when the IVC metrics meet predetermined clinical limits for the patient. ### Claim 25 (depends on 24) The system of claim 24, wherein said physical dimension of the patient's IVC is at least one of IVC diameter or IVC area. ### Claim 26 (depends on 24) The system of claim 24, wherein said instructions further comprise instructions to wirelessly communicate with the implanted sensing device to monitor changes in the measured IVC dimension throughout an euvolemic region defined for said patient. ### Claim 27 (depends on 24) The system of claim 24, wherein said instructions for generating an alert signal include instructions to generate the alert signal while the patient fluid state is within a euvolemic region defined for the patient if the IVC metrics meet said predetermined clinical limits. ### Claim 28 (depends on 24) The system of claim 24, further comprising a user interface configured for user input of patient specific information and a communication link with diagnostic devices monitoring patient condition. ### Claim 29 (depends on 28) The system of claim 28, wherein said user input patient specific information comprises information including at least one of patient age, sex, height, weight, activity level, or health history indicators. ### Claim 30 (depends on 28) The system of claim 28, further comprising at least one of a heart rate monitor, blood pressure monitor or central venous pressure (CVP) monitor, configured to communicate with the patient management system through said communication link to provide patient specific information including at least one of heart rate, blood pressure or CVP. ### Claim 31 (depends on 24) The system of claim 24, wherein: said predetermined clinical limits comprise an indication of the patient fluid state trending towards hypovolemia, and an indication of the patient fluid state trending towards hypervolemia; and each of said predetermined limits falls within the euvolemic range defined for the patient. ### Claim 32 (depends on 24) The system of claim 24, wherein said instructions comprise instructions to set said predetermined clinical limits for the patient based at least in part on input patient specific information. ### Claim 33 (depends on 32) The system of claim 32, wherein said instructions to set the predetermined clinical limits comprise instructions to define (1) a hypovolemic warning zone for said patient encompassing a portion of a defined euvolemic region at the lower end of a euvolemic region adjacent a hypovolemic region and (2) a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent a hypervolemic region, wherein said euvolemic range, hypovolemic range and hypervolemic range are correlated to IVC physical dimension measurements for said patient. ### Claim 34 (depends on 33) The system of claim 33, wherein said instructions to generate the alert signal comprise instructions to generate the alert signal when said IVC metrics indicate the patient fluid state falls within either of the hypovolemic warning zone or the hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 35 (depends on 34) The system of claim 34, further comprising at least one treatment device configured to communicate with the patient management system, wherein said instructions further comprise instructions to initiate a treatment through said at least one treatment device to correct body fluid volume in response to said alert signal while patient fluid volume falls within one of said hypovolemic warning zone of the euvolemic region or said hypervolemic warning zone of the euvolemic region. ### Claim 36 (depends on 35) The system of claim 35, wherein: said instructions to generate an alert signal comprise instructions to generate a hypovolemia alert in response to the IVC metrics indicating a patient fluid state falling within the hypovolemic warning zone; and said instructions to initiate a treatment comprise instructions to initiate at least one of administration of fluids or vasoconstricting drugs in response to said hypovolemia alert. ### Claim 37 (depends on 35) The system of claim 35, wherein: said instructions to generate an alert signal comprise instructions to generate a hypervolemia alert in response to the IVC metrics indicating a patient fluid state falling within the hypervolemic warning zone; and said instructions to initiate a treatment comprise instructions to initiate at least one of dialysis or administration of diuretics or vasodilating drugs in response to said hypervolemia alert. ### Claim 38 (depends on 24) The system of claim 24, wherein said sensing device control module is configured as a function of the patient management system. ### Claim 39 (depends on 23) The system of claim 23, wherein said wireless sensing device comprises an ultrasound transducer and anchor element configured to anchor said ultrasound transducer in the IVC in a fixed position relative to the IVC wall. ### Claim 40 (depends on 23) The system of claim 23, wherein: said wireless sensing device comprises a resilient coil forming a resonant circuit, said resilient coil configured to engage the wall of the IVC and deform therewith to provide a variable characteristic frequency correlated to an IVC physical dimension in response to activation of the resonant circuit; and said system further comprises an antenna configured to activate the resonant circuit and receive the signal representative of the measured IVC physical dimension in response to said activation. ### Claim 41 A system for managing patient body fluid volume, comprising: a wireless sensing device configured to be positioned within the patient IVC to measure at least one of IVC diameter or volume and generate a measurement signal representative of the sensed measurement; a sensing device control module configured to wirelessly receive said measurement signal and output measurement data based on said measurement signal; a processor and memory, the processor configured to receive said measurement data and execute instructions contained in the memory responsive said measurement data and to receive patient specific information, said instructions comprising defining a euvolemic range and at least one of a hypovolemic region and a hypervolemic region for said patient wherein said euvolemic range, hypovolemic region and hypervolemic region are correlated to IVC diameter or volume measurements for the patient, identifying at least one of (i) a hypovolemic warning zone for said patient encompassing a portion of the defined euvolemic region at a lower end of the euvolemic region adjacent the hypovolemic region, and (ii) a hypervolemic warning zone for said patient encompassing a portion of the defined euvolemic region at an upper end of the euvolemic region adjacent the hypervolemic region, and generating an alert signal when measured IVC diameter or volume indicates a patient fluid state falling within either of the hypovolemic warning zone or hypervolemic warning zone of the defined euvolemic region before the patient fluid state reaches one of the hypovolemic region or hypervolemic region, respectively. ### Claim 42 (depends on 41) The system of claim 41, further comprising an interventional device configured to execute a predefined treatment algorithm for delivering a patient fluid therapy automatically in response to said alert signal. ### Claim 43 (depends on 41) The system of claim 41, wherein said alert signal includes a prompt to initiate a patient self-directed treatment or treatment change.