# US 11,027,080 B2 · System and method for determining ventilator leakage during stable periods within a breath > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,027,080 B2 - Document ID: US11027080B2 - Status: Granted - Kind: B2 - Application number: 16/243,245 - Filed: 2019-01-09 - Published: 2019-05-16 - Granted: 2021-06-08 - Earliest claimed: 2008-03-31 - Assignees: Covidien LP - Applicants: Covidien LP - Inventors: Mehdi M. Jafari; Rhomere S. Jimenez; Jeffrey K. Aviano; Gail F. Upham - Web page: https://patentgrep.com/patent/US11027080B2 ## CPC - A61M 16/024: {including calculation means, e.g. using a processor} - A61M 16/0063: {Compressors} - A61M 2016/0021: {with a proportional output signal, e.g. from a thermistor} - A61M 2016/0027: {pressure meter} - A61M 2016/0033: {electrical} - A61M 2205/15: Detection of leaks - A61M 2205/50: with microprocessors or computers - A61M 2205/505: Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches - A61M 2230/46: Resistance or compliance of the lungs - 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 This disclosure describes systems and methods for compensating for leaks in a ventilation system based on data obtained during periods within a breath in which the patient is neither inhaling nor exhaling. The methods and systems described herein more accurately and quickly identify changes in leakage. This information is then to estimate leakage later in the same breath or in subsequent breaths to calculate a more accurate estimate of instantaneous leakage based on current conditions. The estimated leakage is then used to compensate for the leak flow rates, reduce the patient's work of breathing and increase the patient's comfort (patient-ventilator breath phase transition synchrony). ## Claims ### Claim 1 A method for determining leakage in a respiratory gas supply system, the respiratory gas supply system having a controller adapted for delivering a flow of respiratory gases to a breathing patient, the method comprising: monitoring data indicative of at least one of pressure or flow in the respiratory gas supply system; determining, by the controller, that the data indicative of at least one of pressure or flow has been stable for a period of time within a breath of a patient; calculating leakage information based at least in part on the data determined to be stable during the period of time within the breath; determining, by the controller, a leakage rate after the period of time based at least in part on the leakage information; and adjusting at least one of a pressure and a flow delivered to the patient based on the determined leakage rate. ### Claim 2 (depends on 1) The method of claim 1, wherein determining that the data indicative of at least one of pressure or flow has been stable for a period of time is based on a comparison to at least one stability criterion. ### Claim 3 (depends on 1) The method of claim 1, further comprising: displaying the leakage rate to a user on a display. ### Claim 4 (depends on 1) The method of claim 1 wherein determining the leakage rate further comprises: determining an instantaneous leakage rate after the period of time using at least the leakage information and a pressure measurement taken after the period of time. ### Claim 5 (depends on 1) The method of claim 1, wherein determining the leakage rate further comprises: determining an instantaneous leakage rate after the period of time using the leakage information and at least one current pressure measurement. ### Claim 6 (depends on 1) The method of claim 1, further comprising: monitoring data indicative of pressure at two different locations in a patient circuit of the respiratory gas supply system. ### Claim 7 (depends on 1) The method of claim 1, further comprising: monitoring data indicative of flow at two different locations in a patient circuit of the respiratory gas supply system. ### Claim 8 (depends on 1) The method of claim 1, further comprising: monitoring data indicative of at least one of pressure and flow at different locations in a patient circuit of the respiratory gas supply system. ### Claim 9 (depends on 1) The method of claim 1, wherein determining that the data indicative of pressure has been stable for a period of time within a breath of a patient comprises: calculating a first value indicative of a rate of change of pressure during at least a portion of the period of time; comparing the first value to a first stability criterion; and when the first value meets the first stability criterion, classifying the period of time as stable. ### Claim 10 (depends on 1) The method of claim 1, wherein determining that the data indicative of flow has been stable for a period of time within a breath of a patient comprises: calculating a second value indicative of a rate of change of flow during at least a portion of the period of time; comparing the second value to a second stability criterion; and when the second value meets the second stability criterion, classifying the period of time as stable. ### Claim 11 (depends on 1) The method of claim 1, wherein calculating the leakage information comprises: calculating at least one constant based on data taken during the period of time, wherein the constant relates pressure to leakage rate in the respiratory gas supply system. ### Claim 12 (depends on 1) The method of claim 1, wherein calculating the leakage information comprises: calculating a first orifice constant representing the relationship between leakage flow through a hypothetical orifice and pressure in the respiratory gas supply system based on data taken during the period of time. ### Claim 13 (depends on 1) The method of claim 1, wherein determining that the data indicative of at least one of pressure or flow has been stable for a period of time further comprises: periodically analyzing, while providing therapy to the breathing patient, a window of the data, wherein the window comprises recently monitored data, and wherein the periodic analyzing is performed to determine whether the window of the data meets at least one stability criterion. ### Claim 14 A respiratory gas supply system comprising: a pressure generating system configured to control flow of breathing gases through a patient circuit and a patient interface to a patient; and a computer controller communicatively coupled to the pressure generating system for adjusting the flow of breathing gases delivered to the patient, the computer controller configured to: identify a stable period within at least one of an inhalation phase and an exhalation phase of a breath; calculate leakage information using data obtained during the stable period; calculate, during at least one unstable period within the breath or a later breath, an instantaneous leakage rate based on the leakage information; and adjust at least one of a pressure and a flow delivered to the patient based on the instantaneous leakage rate. ### Claim 15 (depends on 14) The respiratory gas supply system of claim 14, wherein identifying the stable period comprises comparing a window of recent pressure or flow data to one or more stability criteria during an inhalation phase. ### Claim 16 (depends on 15) The respiratory gas supply system of claim 15, wherein the one or more stability criteria include at least one of: a first criterion identifying a minimum pressure, a second criterion identifying a maximum pressure variation within the window, a third criterion identifying a maximum flow variation within the window, or a fourth criterion based on a patient circuit type. ### Claim 17 (depends on 14) The respiratory gas supply system of claim 14, wherein identifying the stable period comprises comparing a window of recent pressure or flow data to one or more stability criteria during an exhalation phase. ### Claim 18 (depends on 17) The respiratory gas supply system of claim 17, wherein the one or more stability criteria include at least one of: a fifth criterion identifying a pressure threshold, a sixth criterion identifying a minimum time since the patient began to exhale, a seventh criterion identifying a minimum flow, an eighth criterion identifying a maximum pressure variation within the window, or a ninth criterion identifying a maximum flow variation within the window. ### Claim 19 A method for determining leakage from a respiratory gas supply system, the respiratory gas supply system having a controller adapted for providing respiratory gases to a breathing patient, comprising: identifying, by the controller, at least one stable period within a breath of a patient; calculating leakage information from data indicative of one of pressure or flow obtained during the at least one stable period; subsequent to the at least one stable period, estimating, by the controller, leakage from the respiratory gas supply system based on the leakage information and current data indicative of one of pressure or flow; and adjusting at least one of a pressure or a flow delivered to the patient based on the estimated leakage. ### Claim 20 (depends on 19) The method of claim 19, wherein calculating the leakage information further comprises: calculating a net leakage from the respiratory gas supply system during the at least one stable period based on measurements of flow to the patient and flow exiting the respiratory gas supply system.