# US 2014/0194711 A1 · Patient monitor for determining microcirculation state > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194711 A1 - Document ID: US20140194711A1 - Status: Published application - Kind: A1 - Application number: 14/160,316 - Filed: 2014-01-21 - Published: 2014-07-10 - Earliest claimed: 2010-05-06 - Assignees: Masimo Corporation - Applicants: Masimo Corporation - Inventors: Ammar Al-Ali - Web page: https://patentgrep.com/patent/US20140194711A1 ## CPC - A61B 5/0261: {using optical means, e.g. infrared light} - A61B 5/02007: {Evaluating blood vessel condition, e.g. elasticity, compliance} - A61B 5/02427: {Details of sensor} - A61B 5/14551: {for measuring blood gases} - A61B 5/14552: {Details of sensors specially adapted therefor} - A61B 5/6801: {specially adapted to be attached to or worn on the body surface} - A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor} - A61B 5/7282: {Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818)} - A61B 5/746: {Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract As placement of a physiological monitoring sensor is typically at a sensor site located at an extremity of the body, the state of microcirculation, such as whether vessels are blocked or open, can have a significant effect on the readings at the sensor site. It is therefore desirable to provide a patient monitor and/or physiological monitoring sensor capable of distinguishing the microcirculation state of blood vessels. In some embodiments, the patient monitor and/or sensor provide a warning and/or compensates a measurement based on the microcirculation state. In some embodiments, a microcirculation determination process implementable by the patient monitor and/or sensor is used to determine the state of microcirculation of the patient. ## Claims ### Claim 1 (canceled) ### Claim 2 A patient monitor configured to determine a microcirculation state, the patient monitor comprising: a sensor interface configured to receive a signal from a physiological sensor, the signal indicative of first and second measurement values corresponding to respective first and second physiological parameters, the physiological sensor configured to transmit light of at least one wavelength into tissue of a patient and to detect the light after it has been attenuated by the tissue; and one or more processors configured to: determine a relationship between the first and second physiological parameters; and compare the determined relationship with stored lookup data indicative of a microcirculation state of blood vessels to determine if a blocked or partially blocked microcirculation state exists in at least a portion of blood vessels in the tissue. ### Claim 3 (depends on 2) The patient monitor of claim 2, wherein the first physiological parameter comprises oxygen saturation. ### Claim 4 (depends on 3) The patient monitor of claim 3, wherein the second physiological parameter comprises perfusion index. ### Claim 5 (depends on 4) The patient monitor of claim 4, wherein the physiological sensor comprises a pulse oximeter sensor. ### Claim 6 (depends on 2) The patient monitor of claim 2 further comprising an alarm configured to activate when a blocked or partially blocked microcirculation state is determined to exist. ### Claim 7 (depends on 6) The patient monitor of claim 6, wherein the alarm is configured to activate when the blocked or partially blocked microcirculation state is indicative of cyanosis. ### Claim 8 (depends on 6) The patient monitor of claim 6, wherein the alarm is configured to activate when the blocked or partially blocked microcirculation state is indicative of sepsis. ### Claim 9 (depends on 2) The patient monitor of claim 2, wherein one or more processors are further configured to generate a signal to configure the physiological sensor to measure a light absorption characteristic of the tissue at a different wavelength in response to the determination of the microcirculation state. ### Claim 10 A method of non-invasively determining a microcirculation state, the method comprising: obtaining, at a tissue site by a non-invasive physiological sensor, first and second measurement values corresponding to respective first and second physiological parameters; determining a relationship between the first and second physiological parameters; and comparing the determined relationship with stored lookup data indicative of a microcirculation state of blood vessels to determine if a blocked or partially blocked microcirculation state exists in at least a portion of blood vessels at the tissue site. ### Claim 11 (depends on 10) The method of claim 10, wherein the first physiological parameter comprises oxygen saturation. ### Claim 12 (depends on 11) The method of claim 11, wherein the second physiological parameter comprises perfusion index. ### Claim 13 (depends on 12) The method of claim 12, wherein the non-invasive physiological sensor comprises a pulse oximeter sensor. ### Claim 14 (depends on 10) The method of claim 10, wherein determining a relationship between the first and second physiological parameters comprises generating a ratio of the first measurement value to the second measurement value. ### Claim 15 (depends on 10) The method of claim 10, wherein determining a relationship between the first and second physiological parameters corresponds to generating a trend line based on the stored data points of the first and second physiological parameters. ### Claim 16 (depends on 10) The method of claim 10, wherein the stored lookup data comprises at least one lookup curve. ### Claim 17 (depends on 10) The method of claim 10 further comprising generating an alarm signal when a blocked or partially blocked microcirculation state is determined. ### Claim 18 (depends on 10) The method of claim 10 further comprising applying an offset to at least one of the first physiological parameter or the second physiological parameter to compensate for a blocked or partially blocked microcirculation state. ### Claim 19 A patient monitor configured to determine a microcirculation state, the patient monitor comprising: a sensor interface configured to receive a signal from a physiological sensor, the physiological sensor configured to transmit light of at least one wavelength into living tissue of a patient and to detect the light after it has been attenuated by the tissue; and one or more processors configured to determine a microcirculation state of the tissue based on an analysis of detected attenuated light and at least an oxygen saturation measurement. ### Claim 20 (depends on 19) The patient monitor of claim 19, wherein the microcirculation state comprises one of an unblocked, a blocked, or a partially blocked state. ### Claim 21 (depends on 20) The patient monitor of claim 20 further comprising an alarm configured to activate when a blocked or partially blocked microcirculation state is detected. ### Claim 22 (depends on 19) The patient monitor of claim 19, wherein one or more processors are further configured to generate a signal to configure the physiological sensor to measure the light absorption characteristic of the tissue monitoring site at a different wavelength in response to the determination of the microcirculation state. ### Claim 23 (depends on 19) The patient monitor of claim 19, wherein the physiological sensor comprises a pulse oximeter sensor. ### Claim 24 (depends on 19) The patient monitor of claim 19 further comprising an alarm configured to activate when cyanosis is detected based at least partly on the microcirculation state of the tissue. ### Claim 25 (depends on 19) The patient monitor of claim 19 further comprising an alarm configured to activate when sepsis is detected based at least partly on the microcirculation state of the tissue.