# US 11,298,481 B2 · Non-gas analyzer monitor of inspired gas concentration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,481 B2 - Document ID: US11298481B2 - Status: Granted - Kind: B2 - Application number: 15/268,464 - Filed: 2016-09-16 - Published: 2017-03-16 - Granted: 2022-04-12 - Earliest claimed: 2015-09-16 - Assignees: 12th Man Technologies, Inc. - Applicants: 12th Man Technologies, Inc. - Inventors: Steve Han; Alex Stenzler; Martin Stegenga - Web page: https://patentgrep.com/patent/US11298481B2 ## CPC - A61M 16/0051: {with alarm devices} - A61M 16/0057: {Pumps therefor} - A61M 16/125: {Diluting primary gas with ambient air} - A61M 16/204: {used for inhalation control} - A62B 7/02: with compressed oxygen or air - G01N 11/04: through a restricted passage, e.g. tube, aperture - G01N 33/0022: {using a number of analysing channels} - G01N 33/0031: {comprising two or more sensors, e.g. a sensor array} - A61M 2016/0027: {pressure meter} - A61M 2016/0039: {in the inspiratory circuit} - A61M 2016/102: {Measuring a parameter of the content of the delivered gas} - A61M 2205/18: with alarm - A61M 2205/3334: Measuring or controlling the flow rate - A61M 2205/502: User interfaces, e.g. screens or keyboards - 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)} - A62B: DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING (valves specially adapted for medical use A61M39/00; life-saving devices, apparatus or methods specially adapted for use in water B63C9/00; divers' equipment B63C11/00; specially adopted for use with aircraft, e.g. parachutes, ejector seats, {B64D17/00, B64D25/10}; rescue devices peculiar to mining E21F11/00) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A system for monitoring inspirable gas for delivery to a patient includes a branched breathing circuit having a first branch conduit and a second branch conduit. The first branch conduit is fluidly connected to a first gas source and the second branch conduit is fluidly connected to a second gas source, and the first and second branch conduits merge into a patient delivery conduit. The system includes a first flow sensor in the first branch conduit, a second flow sensor in the second branch conduit, and a third flow sensor in the patient delivery conduit. A control unit is electrically coupled to the first, second and third flow sensors. The control unit is configured to determine a blend of gas in the patient delivery circuit based on a measured flow from the third flow sensor and a measured flow from at least one of the first and second flow sensors. ## Claims ### Claim 1 A system for monitoring an inspirable gas concentration for delivery to a patient, comprising: a pumpless branched breathing circuit comprising a first branch conduit and a second branch conduit, wherein the first branch conduit is fluidly connected to a first gas source having a first gas concentration and the second branch conduit is fluidly connected to a second gas source having a second gas concentration, wherein the first and second branch conduits merge directly into a patient delivery conduit without passing through a mixing chamber or a mixed gas control valve, wherein the patient delivery conduit downstream of the merge does not comprise a pressure sensor, and wherein the pumpless branched breathing circuit does not comprise an exhalation valve; a first flow sensor in the first branch conduit configured to generate a first flow measurement, a second flow sensor in the second branch conduit configured to generate a second flow measurement, and a third flow sensor in the patient delivery conduit configured to generate a third flow measurement; and a control unit electrically coupled to the first, second and third flow sensors; wherein the control unit is configured to: determine a blended gas concentration comprising the second gas in a blend of gas in the patient delivery circuit based on the third flow measurement and at least one of the first and second flow measurements, and monitor in parallel, first and second comparisons, triggering an alarm or a safety feature when the first or second comparisons fail, the first comparison based on comparing a sum of the first and second flow measurement to the third flow measurement, and the second comparison based on comparing the blended gas concentration in the patient delivery conduit to a preset target patient gas concentration. ### Claim 2 (depends on 1) The system of claim 1, wherein the second gas source is a pressurized container comprising the second gas. ### Claim 3 (depends on 1) The system of claim 1, wherein the first gas source is at least one of a ventilator, room air and ambient air. ### Claim 4 (depends on 1) The system of claim 1, wherein the first gas source is pressurized to a pressure differential of less than 3 psi. ### Claim 5 (depends on 1) The system of claim 1, wherein the first gas source is unpressurized air. ### Claim 6 (depends on 1) The system of claim 1 further comprising: a valve in the second branch conduit upstream of the second flow sensor; wherein the control unit is configured to adjust the valve based on the first, second and third flow measurements. ### Claim 7 (depends on 6) The system of claim 6, wherein the valve is a proportional flow control valve. ### Claim 8 (depends on 1) The system of claim 1, wherein the control unit is a microcontroller. ### Claim 9 (depends on 1) The system of claim 1, wherein the control unit is configured to generate a correction signal based on a flow measurement signal received from the second flow sensor. ### Claim 10 (depends on 9) The system of claim 9, wherein the control unit is configured to integrate one or more of the first, second and third flow measurements. ### Claim 11 (depends on 1) The system of claim 1, wherein the control unit is configured to accept a source gas concentration value and a target patient gas concentration value as input. ### Claim 12 (depends on 1) The system of claim 1, wherein the control unit is configured to calculate a concentration value of the second gas delivered through the patient delivery conduit in real time with each breath of a patient. ### Claim 13 (depends on 1) The system of claim 1, wherein the control unit is configured to trigger the alarm based on a calculation comparing two integrated flow values of the measured flow from at least one of the first and second flow sensors to a third integrated flow value of the measured flow from at least one of the first and second flow sensors. ### Claim 14 (depends on 1) The system of claim 1, wherein the control unit is configured to trigger the alarm based on a calculation comparing two instantaneous flow values to a third instantaneous flow value. ### Claim 15 (depends on 1) The system of claim 1 further comprising: an input device electrically coupled to the control unit, wherein the control unit is configured to receive input from the input device including both the target patient gas concentration and at least one of the first and second gas concentrations. ### Claim 16 (depends on 1) The system of claim 1 further comprising: a pressure monitoring element disposed on the second branch conduit and electrically coupled to the control unit. ### Claim 17 (depends on 16) The system of claim 16, wherein the pressure monitoring element is a pressure transducer. ### Claim 18 (depends on 16) The system of claim 16, wherein the first gas source is a unit dose container comprising the first gas, and wherein the control unit is configured to receive a pressure measurement signal from the pressure monitoring element and activate the safety feature corresponding to the received pressure measurement signal. ### Claim 19 (depends on 18) The system of claim 18, wherein the control unit is configured to activate the safety feature based on a value corresponding to a change in the received pressure measurement signal and an integral of a flow measurement signal received from at least one of the first, second and third flow sensors. ### Claim 20 (depends on 1) The system of claim 1, wherein the control unit is configured to activate the safety feature that automatically shuts off the flow of gas from at least one of the first or second gas source when a threshold integral measurement of measured flow from at least one of the first and second flow sensors is reached. ### Claim 21 A method for monitoring an inspired gas concentration in a branched breathing circuit, the method comprising: providing a pumpless branched breathing circuit comprising a controller, a first branch conduit and a second branch conduit, wherein the first branch conduit is fluidly connected to a first gas source having a first gas concentration and the second branch conduit is fluidly connected to a second gas source having a second gas concentration, wherein the first and second branch conduits merge directly into a patient delivery conduit without passing through a mixing chamber or a mixed gas control valve, wherein the patient delivery conduit downstream of the merge does not comprise a pressure sensor, and wherein the pumpless branched breathing circuit does not comprise an exhalation valve, the controller executing a method comprising the steps of; measuring a flow of gas in the first branch conduit; measuring a flow of gas in the second branch conduit; measuring a flow of gas in the patient delivery conduit; comparing the measured flow of gas in the patient delivery conduit to at least one of the measured flow of gas in the first and second branch conduits; determining a blended concentration comprising the second gas in a blend of gas in the patient delivery conduit; and monitoring in parallel, first and second comparisons, triggering a safety feature or an alarm if the first or second comparisons fail, the first comparison based on comparing a sum of the measured flow of gas in the first branch conduit first and the measured flow of gas in the second branch conduit to the measured flow of gas in the patient delivery conduit, and the second comparison based on comparing the blended concentration in the patient delivery conduit to a preset target concentration. ### Claim 22 (depends on 21) The method of claim 21, wherein comparing the measured flow of gas further comprises comparing the measured flow of gas in the first or second branch conduit to the measured flow of gas in the patient delivery conduit. ### Claim 23 (depends on 21) The method of claim 21, wherein comparing the measured flow of gas further comprises comparing the measured flow of gas in the first or second branch conduit to the measured flow of measured gas in both the first and second branch conduits. ### Claim 24 (depends on 21) The method of claim 21, further comprising the step of adjusting the flow of gas from at least one of the first and second gas sources based on the determined blend of gas in the patient delivery conduit. ### Claim 25 (depends on 21) The method of claim 21, further comprising the step of triggering the alarm based on the determined blend of gas in the patient delivery conduit. ### Claim 26 (depends on 21) The method of claim 21, further comprising the step of triggering the safety feature or the alarm based on a pressure measured from the second branch conduit. ### Claim 27 (depends on 21) The method of claim 21, further comprising the step of activating the safety feature based on both a change in a pressure measured from the second branch conduit and an integrated first flow measurement.