# US 10,478,081 B2 · Systems and method for identifying the need for measurement of cardiac output > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,478,081 B2 - Document ID: US10478081B2 - Status: Granted - Kind: B2 - Application number: 15/541,795 - Filed: 2016-01-08 - Published: 2018-01-04 - Granted: 2019-11-19 - Earliest claimed: 2015-01-09 - Assignees: Mermaid Care A/S - Applicants: Mermaid Care A/S - Inventors: Stephen Edward Rees; Dan Stieper Karbing - Web page: https://patentgrep.com/patent/US10478081B2 ## CPC - A61B 5/029: Measuring blood output from the heart, e.g. minute volume - A61B 5/0833: {Measuring rate of oxygen consumption} - A61B 5/14542: {for measuring blood gases (A61B5/14551 takes precedence)} - A61B 5/14551: {for measuring blood gases} - A61B 5/7246: {using correlation, e.g. template matching or determination of similarity} - A61B 5/7278: {Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals} - G16H 50/30: for calculating health indices; for individual health risk assessment - G16H 50/50: for simulation or modelling of medical disorders - A61B 5/6852: {Catheters} - A61B 2505/03: Intensive care - G16H 40/63: for local operation - G16H 50/20: for computer-aided diagnosis, e.g. based on medical expert systems - 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 The present invention relates to a decision support system (DSS), a medical monitoring system (100), and a corresponding method for identifying the need for measurement of cardiac output (CO) based on one or more comparisons (COMP1, COMP2) in a physiological model. More specifically, for identifying when an approximated value of CO cannot be correct due to circulatory compromise and as such that another estimated or measured value of CO is required. ## Claims ### Claim 1 A decision support system (DSS) for providing medical decision support for cardiac output (CO) measurements in connection with an associated patient (P) using one or more physiological models (MOD1) implemented on a computer system, the computer system being configured for: receiving first data (D1) indicative of an arterial oxygenation (SaO2, SpO2) in the blood of the patient; receiving second data (D2) indicative of a haemoglobin concentration (Hb) in the blood of the patient; the decision support system being configured for: applying the physiological model(s) (MOD1) of the patient using said first data (D1) and said second data (D2) for modelling a tissue metabolism in the patient; A) i. outputting from said physiological model(s) (MOD1), using a preliminary value for a cardiac output (CO_PREL), an estimated measure indicative of haemoglobin oxygen saturation in mixed venous blood of the patient (SvO2_EST); and ii. performing a first comparison (COMP1) of said estimated measure indicative of the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_EST) with a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF); and/or B) iii. outputting from said physiological model(s) (MOD1), using a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF), an estimated value indicative of the cardiac output (CO_EST) in the patient; and iv. performing a second comparison (COMP2) of said estimated value indicative for the cardiac output (CO_EST) with a reference value for the cardiac output (CO_REF) in patient; and based on said first comparison (COMP1, step ii of A) and/or said second comparison (COMP2, step iv of B) generating a measure (NM_CO) indicative of a need for an improved measurement and/or estimation of the cardiac output (CO). ### Claim 2 (depends on 1) The decision support system (DSS) according to claim 1, the computer system being further configured for receiving third data (D3) indicative of an oxygen partial pressure in the arterial blood (PaO2) of the patient. ### Claim 3 (depends on 1) The decision support system (DSS) according to claim 1, the computer system being further ranged configured for receiving fourth data (D4) indicative of a rate of oxygen consumption ({dot over (V)}O_2) of the patient. ### Claim 4 (depends on 3) The decision support system (DSS) according to claim 3, further configured for applying the physiological model(s) (MOD1) of the patient using said third data (D3) and/or said fourth data (D4) for modelling the tissue metabolism in the patient. ### Claim 5 (depends on 1) The decision support system (DSS) according to claim 1, wherein said preliminary value for the cardiac output (CO_PREL) is a value representative for a specific patient (P1), dependent on age, gender, weight, and/or one, or more, clinical conditions having an impact on the cardiac output (CO). ### Claim 6 (depends on 1) The decision support system (DSS) according to claim 1, wherein said first comparison (COMP1) comprises an evaluation of whether or not the said estimated measure indicative of the haemoglobin oxygen saturation in the mixed venous blood of the specific patient (SvO2_EST) is physiologically possible. ### Claim 7 (depends on 1) The decision support system (DSS) according to claim 1, wherein the said reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF, iii) is a minimum value, of 40% or 60%, or of 50%. ### Claim 8 (depends on 1) The decision support system (DSS) according to claim 1, wherein the said reference value for the haemoglobin oxygen saturation in the mixed venous blood of the specific patient (SvO2_REF, iii) is a value dependent on age, gender, weight, and/or one, or more, clinical conditions having an impact on the cardiac output (CO), and/or on the received fourth data (D4, {dot over (V)}O_2). ### Claim 9 (depends on 8) The decision support system (DSS) according to claim 8, wherein said second comparison (COMP2) comprises an evaluation of whether or not said estimated value indicative for the cardiac output (CO_EST) of the specific patient is physiologically possible. ### Claim 10 (depends on 1) The decision support system (DSS) according to claim 1, wherein said measure (NM_CO) indicative of the need for an improved measurement and/or estimation of the cardiac output (CO) is a quantitative measure, the quantitative measure being a number indicating the need for an improved measurement and/or estimation of the cardiac output (CO), or an qualitative measure. ### Claim 11 (depends on 1) The decision support system (DSS) according to claim 1, wherein the first data (D1) and/or the third data (D3) is based, wholly or partly, on a second physiological model (MOD2) of an acid-base system of the blood of the patient and/or of an interstitial fluid of the patient. ### Claim 12 (depends on 11) The decision support system (DSS) according to claim 11, wherein the second physiological model (MOD2) receives data from a third physiological model (MOD3) of a pulmonary gas exchange, the third physiological model (MOD3) receiving data from ventilation measurements of the patient (P). ### Claim 13 (depends on 1) The decision support system (DSS) according to claim 1, wherein the first data (D1), the second data (D2), the third data (D3) and/or the third data (D4) is additionally based, wholly or partly, on, one or more, physiological models representing respiratory drive of patient and/or lung mechanics of the patient. ### Claim 14 A medical monitoring system capable of providing medical decision support for cardiac output (CO) measurements in connection with an associated patient (P,1) using one or more physiological models (MOD1) implemented on a computer system, the computer system being configured for: providing first data (D1) indicative of an arterial oxygenation (SaO2, SpO2) in the blood of the patient, by corresponding first measurement means (M); providing second data (D2) indicative of a haemoglobin concentration (Hb) in the blood of the patient, by corresponding second measurement means (M2); the medical monitoring system being configured for: applying the physiological model(s) (MOD1) of the patient using said first data (D1) and said second data (D2) for modelling a tissue metabolism in the patient; A) i. outputting from said physiological model (MOD1), using a preliminary value for the cardiac output (CO_PREL), an estimated measure indicative of the haemoglobin oxygen saturation in mixed venous blood of the patient (SvO2_EST); and ii. performing a first comparison (COMP1) of said estimated measure indicative of the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_EST) with a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF); and/or B) iii. outputting from said physiological model (MOD1), using a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF), an estimated value indicative of the cardiac output (CO_EST) in the patient; and iv. performing a second comparison (COMP2) of said estimated value indicative for the cardiac output (CO_EST) with a reference value for the cardiac output (CO_REF) in patient; and based on said first comparison (COMP1, step ii of A) and/or said second comparison (COMP2, step iv of B) generating a measure (NM_CO) indicative of a need for an improved measurement and/or estimation of the cardiac output (CO). ### Claim 15 (depends on 14) The medical monitoring system according to claim 14, the computer system being further configured for providing third data (D3) indicative of an oxygen partial pressure in the arterial blood (PaO2) of the patient, by corresponding third measurement means (M3). ### Claim 16 (depends on 15) The medical monitoring system according to claim 15, the computer system being further configured for providing fourth data (D4) indicative of a rate of oxygen consumption (V O_2) of the patient, by corresponding fourth measurement means (M4). ### Claim 17 (depends on 16) The medical monitoring system according to claim 16, further configured for applying the physiological model(s) (MOD1) of the patient using said third data (D3) and/or said fourth data (D4) for modelling the tissue metabolism in the patient. ### Claim 18 A method for providing medical decision support for cardiac output (CO) measurements in connection with a patient (P,1) using one or more physiological models (MOD1) implemented on a computer system, the computer system being configured for: receiving first data (D1) indicative of an arterial oxygenation (SaO2, SpO2) in the blood of the patient; receiving second data indicative of a haemoglobin concentration (Hb) in the blood of the patient; the method comprising the steps of: applying the physiological model(s) (MOD1) of the patient using said first data (D1), said second data (D2) for modelling a tissue metabolism in the patient; A) i. outputting from said physiological model (MOD1), using a preliminary value for the cardiac output (CO_PREL), an estimated measure indicative of a haemoglobin oxygen saturation in mixed venous blood of the patient (SvO2_EST); and ii. performing a first comparison (COMP1) of said estimated measure indicative of the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_EST) with a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF); and/or B) iii. outputting from said physiological model (MOD1), using a reference value for the haemoglobin oxygen saturation in the mixed venous blood of the patient (SvO2_REF), an estimated value indicative of the cardiac output (CO_EST) in the patient; and iv. performing a second comparison (COMP2) of said estimated value indicative for the cardiac output (CO_EST) with a reference value for the cardiac output (CO_REF) in the patient; and generating a measure (NM_CO) indicative of a need for an improved measurement and/or estimation of the cardiac output (CO) based on said first comparison (COMP1, step ii of A) and/or said second comparison (COMP2, step iv of B). ### Claim 19 (depends on 18) The method according to claim 18, the computer system being further configured for receiving third data (D3) indicative of an oxygen partial pressure in the arterial blood (PaO2) of the patient. ### Claim 20 (depends on 19) The method according to claim 19, the computer system being further configured for receiving fourth data (D4) indicative of a rate of oxygen consumption ({dot over (V)}O_2) of the patient. ### Claim 21 (depends on 20) The method according to claim 20, further comprising the step of applying the physiological model(s) (MOD1) of the patient using said third data (D3) and/or said fourth data (D4) for modelling the tissue metabolism in the patient.