# US 9,956,363 B2 · Systems and methods for triggering and cycling a ventilator based on reconstructed patient effort signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,956,363 B2 - Document ID: US9956363B2 - Status: Granted - Kind: B2 - Application number: 14/797,681 - Filed: 2015-07-13 - Published: 2015-11-05 - Granted: 2018-05-01 - Earliest claimed: 2008-06-06 - Assignees: Covidien LP - Applicants: Covidien LP - Inventors: Milenko Masic - Web page: https://patentgrep.com/patent/US9956363B2 ## CPC - A61M 16/0003: {Accessories therefor, e.g. sensors, vibrators, negative pressure} - A61B 5/08: Measuring devices for evaluating the respiratory organs - A61M 16/0051: {with alarm devices} - A61M 16/0057: {Pumps therefor} - A61M 16/026: {specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis} - A61M 16/12: by mixing different gases - G01F 1/00: Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow (measuring a proportion of the volume flow G01F5/00) - G01F 1/34: by measuring pressure or differential pressure - A61M 2016/0015: {inhalation detectors} - A61M 2016/0018: {electrical} - A61M 2016/0027: {pressure meter} - A61M 2016/0036: {in the breathing tube and used in both inspiratory and expiratory phase} - A61M 2016/0039: {in the inspiratory circuit} - A61M 2016/0042: {in the expiratory circuit} - A61M 2205/3303: Using a biosensor - A61M 2205/50: with microprocessors or computers - 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)} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME ## Abstract Various embodiments of the present disclosure provide systems, methods and devices for respiratory support. As one example, a method for respiratory support is described that includes providing a measured pressure, and calculating a net flow based on at least one measured inlet flow and measured outlet flow. A relationship between a first value related to the measured pressure, a second value related to the measured net flow and a third value related to patient effort is used to provide a prediction of patient effort. An interim value is updated based at least in part on the prediction of the patient effort, and used to help compute a patient effort. A ventilation cycle is initiated using the computed patient effort. ## Claims ### Claim 1 A method for respiratory support, the method comprising: delivering a measured pressure; calculating a net flow based on at least one measured inlet flow and at least one measured outlet flow; using a relationship between a first value related to the measured pressure, a second value related to the net flow and a third value related to patient effort to provide an estimate of patient effort, wherein the third value related to patient effort represents at least one unknown value, and wherein the estimate of patient effort is determined based on the unknown value being characterized by a smooth signal; updating an interim value used to calculate a previous computed patient effort based at least in part on the estimate of patient effort, wherein the interim value is represented by a composite parameter that does not directly correspond to a particular respiratory parameter; calculating a computed patient effort based at least in part on the updated interim value; and utilizing the computed patient effort to trigger a ventilation cycle. ### Claim 2 (depends on 1) The method of claim 1, wherein the computed patient effort is a filtered patient effort signal. ### Claim 3 (depends on 1) The method of claim 1, wherein the computed patient effort is a linear function of a derivative of actual patient effort. ### Claim 4 (depends on 3) The method of claim 3, wherein the linear function includes a filter function. ### Claim 5 (depends on 1) The method of claim 1, wherein utilizing the computed patient effort to trigger the ventilation cycle includes determining a negative zero crossing of the computed patient effort, and initiating the ventilation cycle based at least in part on the negative zero crossing of the computed patient effort. ### Claim 6 (depends on 1) The method of claim 1, wherein utilizing the computed patient effort to trigger the ventilation cycle includes determining a positive zero crossing of the computed patient effort, and terminating the ventilation cycle based at least in part on the positive zero crossing of the computed patient effort. ### Claim 7 (depends on 1) The method of claim 1, wherein utilizing the computed patient effort to trigger the ventilation cycle includes determining an onset condition related to the computed patient effort, and initiating the ventilation cycle based at least in part on the onset condition. ### Claim 8 (depends on 7) The method of claim 7, wherein the computed patient effort is a function of a derivative of actual patient effort, and wherein determining the onset condition includes determining whether the computed patient effort passes through a threshold value with a negative slope. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the onset condition occurs outside of an inspiration cycle. ### Claim 10 (depends on 8) The method of claim 8, wherein the threshold value is zero. ### Claim 11 (depends on 1) The method of claim 1, wherein utilizing the computed patient effort to trigger the ventilation cycle includes determining an end condition, and terminating the ventilation cycle based at least in part on the end condition. ### Claim 12 (depends on 11) The method of claim 11, wherein the computed patient effort is a function of a derivative of actual patient effort, and wherein determining the end condition includes determining whether the computed patient effort passes through a threshold value with a positive slope. ### Claim 13 (depends on 12) The method of claim 12, wherein determining the end condition occurs during an inspiration cycle. ### Claim 14 (depends on 12) The method of claim 12, wherein the threshold value is zero. ### Claim 15 A ventilation system, the ventilation system comprising: a processor communicably coupled to a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to: receive a pressure value; determine a net flow based on an inlet flow value and an outlet flow value; use a relationship between a first value related to the pressure, a second value related to the net flow, and a third value related to patient effort to calculate an estimated patient effort, wherein the third value related to patient effort represents at least one unknown value, and wherein the estimate of patient effort is determined based on the unknown value being characterized by a smooth signal; update an interim value used to calculate a previous computed patient effort based at least in part on the estimated patient effort, wherein the interim value is represented by a composite parameter that does not directly correspond to a particular respiratory parameter; calculate a computed patient effort based at least in part on the updated interim value; and initiate a ventilation cycle based at least in part on the computed patient effort. ### Claim 16 (depends on 15) The system of claim 15, wherein initiating the ventilation cycle includes determining an end condition, and terminating the ventilation cycle based at least in part on the end condition. ### Claim 17 (depends on 16) The system of claim 16, wherein the computed patient effort is a function of a derivative of actual patient effort, and wherein determining the end condition includes determining whether the computed patient effort passes through a threshold value with a positive slope. ### Claim 18 (depends on 15) The system of claim 15, wherein initiating the ventilation cycle includes determining an onset condition, and triggering the ventilation cycle based at least in part on the onset condition. ### Claim 19 (depends on 18) The system of claim 18, wherein the computed patient effort is a function of a derivative of actual patient effort, and wherein determining the onset condition includes determining whether the computed patient effort passes through a threshold value with a negative slope. ### Claim 20 A patient ventilator, the ventilator comprising: a gas inlet; a gas outlet; a tube coupling the gas inlet and the gas outlet; a pressure sensor, wherein the pressure sensor is operable to provide a measured pressure indicating a pressure in the tube; a first flow sensor, wherein the first flow sensor is operable to provide an inlet flow value indicating a flow associated with the gas inlet; a second flow sensor, wherein the second flow sensor is operable to provide an outlet flow value indicating a flow associated with the gas outlet; and a processor communicably coupled to a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to: receive the measured pressure; calculate a net flow based at least in part on an inlet flow value and an outlet flow value; use a relationship between a first value related to the measured pressure, a second value related to the net flow and a third value related to patient effort to provide an estimated patient effort, wherein the third value related to patient effort represents at least one unknown value, and wherein the estimate of patient effort is determined based on the unknown value being characterized by a smooth signal; update an interim value used to calculate a previous computed patient effort based at least in part on the estimated patient effort, wherein the interim value is represented by a composite parameter that does not directly correspond to a particular respiratory parameter; calculate a computed patient effort based at least in part on the updated interim value; and initiate a ventilation cycle based at least in part on the computed patient effort.