JPWO2020178746A5 - - Google Patents

Description

The present disclosure relates to methods and systems for providing respiratory flow therapy to a patient. In particular, the present disclosure relates to detecting whether a patient is attached to a respiratory flow system.

Breathing aid devices are used in a variety of settings, such as hospitals, medical facilities, home care or home settings, to deliver a flow of gas to a user or patient. Respiratory assistance or respiratory therapy devices (collectively, “respiratory apparatus” or “respiratory devices”) may be used to deliver supplemental oxygen or other gases with the gas flow and/or heat and humidify A humidifier may be used to deliver the gas. Breathing devices may allow regulation and control over gas flow characteristics, including flow rate, temperature, gas concentration, humidity, pressure, and the like. Gas flow characteristics are measured using sensors such as flow sensors and/or pressure sensors.

Respiratory devices are capable of monitoring and determining various parameters related to patient use of the device. The parametric data can inform clinicians regarding the patient's health, respiratory device use, and/or progress of the patient's respiratory function. Such data can also be used to improve the functionality of the respiratory device itself.

Inhalation and exhalation by a patient using a respiratory device can affect gas flow within the device. This is because when the patient inhales through a patient interface, such as a mask or nasal cannula, the resistance to gas flow within the patient interface decreases, and when the patient exhales, the resistance to gas flow within the patient interface increases. It's for. Some parameters, such as respiratory rate, are determined by monitoring inspiratory and expiratory changes in the flow parameter signal.

In closed systems, this inspiration and expiration are relatively easy to measure. However, in non-sealed systems such as nasal high flow systems, patient inspiration and expiration are more difficult to establish due to the open nature of the system. Irregularities in signals, particularly time domain signals, can be easily misinterpreted as respiratory trigger events. Parameters determined from such analysis may be used by the respiratory device to signal when there is no breath (e.g., the patient is detached, not breathing through the nose, and/or for other reasons). If there is a possibility of detection, it can be misleading.

The present disclosure performs a time-domain analysis of gas flow parameters to determine correlation values of flow parameter data and compares the correlation values to one or more threshold values to connect and disconnect to a patient's respiratory system. provide a process for detecting In addition, the processes described herein classify the patient connection status into one of four categories: detached, attaching, attached or detaching. can be classified into one of

Determining patient connection status, for example, synchronizes the delivery of gases when the patient is connected, and when the patient removes the patient interface, oxygen delivery control, and/or flow and flow to heating elements within the device. /or interrupt control of power, improve the accuracy of determining other parameters such as respiratory rate, and/or provide long-term trends in therapy compliance and usage information and/or progression of patient respiratory function, etc. For this reason, it can be supplied to other control functions of the respiratory device and/or other patient monitoring devices. The processes disclosed herein allow the patient interface to be a non-sealing device, such as a nasal cannula in nasal high-flow therapy, or (such as in continuous positive airway pressure (CPAP) therapy and/or biphasic positive airway pressure therapy). It can be used with any other patient interface such as a face mask, nasal mask, nasal pillow mask, endotracheal tube, tracheostomy interface, and the like.

In one configuration, a respiratory system configured to provide respiratory therapy to a patient and to provide information related to the patient's breathing can comprise a respiratory device comprising a controller, the controller comprising gas Receiving data for a first parameter representative of the flow or performance of a component of the device, the first parameter being indicative of patient respiration; It can be configured to correlate the parametric data and use the correlation value to determine that the patient is connected to the patient interface of the device.

In one configuration, the controller can be configured to evaluate the correlation value for a subset of the first parameter data.

In one configuration, the size of the subset may be selected such that frequencies within the typical breathing frequency range provide higher correlation than other frequencies above the typical breathing frequency range.

In one configuration, the size of the subset can be selected such that the subset contains data from a predetermined time span.

In one configuration, the correlation value can be determined by analyzing the correlation between the first parameter data and one or more feature vectors.

In one configuration, the controller may be configured to filter the correlation values over time to provide filtered correlation values.

In one configuration, the controller can be configured to determine that the patient is connected to the patient interface if the filtered correlation value exceeds a first threshold.

In one configuration, the controller can be configured to determine that the patient is connected to the patient interface if the filtered correlation value is above the second threshold for a fixed amount of time.

In one configuration, the first threshold can exceed the second threshold.

In one configuration, the patient may be determined to be disconnected if the filtered correlation value is below a third threshold once determined to be connected.

In one configuration, a patient may be determined to be disconnected if, once determined to be connected, the filtered correlation value is below a fourth threshold for a certain amount of time.

In one configuration, the third threshold can be below the fourth threshold.

In one configuration, the fourth threshold can be equal to the second threshold. In one configuration, the fourth threshold can be below the second threshold.

In one configuration, if the patient has not yet been assumed to be connected and the filtered correlation value is between the first and second thresholds for less than a certain amount of time , the patient can be configured to be determined to be connected.

In one configuration, the patient may be determined to be disconnected if the correlation value falls below a second threshold once it is determined to be connected.

In one configuration, if the patient has not yet been assumed to be uncoupled and the filtered correlation value is between the third and fourth thresholds for less than a certain amount of time , the patient can be configured to be determined to be in dissection.

In one configuration, it can be determined that the patient is connected if the correlation value exceeds the previous fourth threshold once it is determined to be disconnected.

In one configuration, the controller can use the determination of whether a patient is connected to determine whether to display certain parameters.

In one configuration, the controller may receive an estimate of the patient's respiration rate and display the respiration rate estimate when the patient is determined to be connected.

In one configuration, the device can be configured to synchronize the delivery of gas with the patient's breathing if the patient is determined to be connected.

In one configuration, the controller can log the time of each patient connection status.

In one configuration, the device can generate an alarm when the patient is disconnected.

In one configuration, the device is configured to generate an alarm immediately after the patient is disconnected. In one example, the device is configured to generate an alert in real-time when a patient is detected as disconnected.

In one configuration, the device is configured to generate an alarm following a preset time (ie, a predetermined amount of time) after the patient has been disconnected.

In one configuration, the preset time can be from about 10 seconds to about 10 minutes. In one example, the device is configured to generate an alarm if the device detects the patient as disconnected for a preset amount of time. In one example, the preset time is at least 1 minute.

In one example, the preset time can be from about 30 seconds to about 5 minutes.

In one example, the preset time can be from about 1 minute to about 2 minutes. In one example , the preset time can be 2-3 minutes . The device is configured to wait a predetermined time (i.e., a preset time) so that the patient or medical professional can recondition the removed nasal cannula in the event of inadvertent removal of the cannula. . The device is configured to deliver an alarm to alert the patient and/or medical professional that the patient is not receiving gas flow if the cannula is detected as out of preset time. The alarm provides warning if the patient is not receiving treatment, thereby improving system safety and reducing the likelihood that the patient will not receive treatment due to being removed.

In one configuration, the alert can be output through a nurse call port.

In one configuration, the alert can be accompanied by the device providing the user with an option to see if the patient is still connected. This option can be presented in a graphical user interface. This option can be presented as a button or window that can be selected via the user interface.

In one configuration, the option to check if the patient is still connected can be used to override the determination that the patient is disconnected.

In one configuration, the device can suspend recording of certain patient parameters only when the patient is disconnected.

In one configuration, patient parameters can include oxygen efficiency.

In one configuration, oxygen efficiency can be based on _SpO2 and _FdO2 .

In one configuration, the device can include a make-up gas inlet and a valve, and the valve can be adjusted by the controller to regulate the flow of make-up gas through the make-up gas inlet. In one example, the make-up gas can be oxygen or can be nitrogen.

In one configuration, the controller can close the valve when the patient is disconnected. This reduces waste of make-up gas when the patient is not connected or disconnected. The controller can be configured to close the valve and can be configured to reopen the valve when a patient is detected as connected.

In one configuration, the controller can control the flow generator to achieve a flow rate, and the controller can adjust the flow rate when the patient is disconnected. The flow generator can be a blower.

In one configuration, adjusting the flow rate can include reducing the flow rate.

In one configuration, adjusting the flow rate can include increasing the flow rate. The controller can be configured, for example, if the nasal cannula is partially dislodged, increase the flow rate to overcome the partial dislodgement. The increased flow helps to continue to provide respiratory gas to the patient so that the patient can receive respiratory therapy. Respiratory therapy, in one example, can be high flow therapy. The increased flow can deliver an adequate amount of gas flow to the patient even if the patient interface is detected as being partially dislodged and removed.

In one configuration, the increase in flow rate can continue for an initial period.

In one configuration, the initial period of time can be from about 10 seconds to about 10 minutes.

In one configuration, the initial period of time can be from about 30 seconds to about 5 minutes.

In one configuration, the initial period of time can be from about 1 minute to about 2 minutes.

In one configuration, the controller can reduce the flow rate when it is determined that the patient is still disconnected after the initial period. Reducing the flow rate after the initial period helps protect the flow generator (eg, blower) from overwork. This may be useful when the respiratory therapy device is operating using batteries. Turning off the blower or reducing flow can help conserve battery power.

In one configuration, the first parameter data can include the absolute value of the first parameter. In one configuration, the first parameter data can include changes in the first parameter.

In one configuration, the change may be determined by subtracting the target value of the first parameter from the measured value of the first parameter. In one configuration, the change can be determined by subtracting the estimated influence of the second parameter from the measured value of the first parameter.

In one configuration, the first parameter may be flow rate. In one configuration, the first parameter can be pressure.

In one configuration, the second parameter may be motor speed. In one configuration, the second parameter can be pressure.

In one configuration, the system can be a non-sealed system.

In one configuration, the patient interface can include a nasal cannula or tracheostomy interface.

In one configuration, the system can be configured to provide nasal high flow therapy.

In one configuration, the system can be a closed system.

In one configuration, the system can include a patient interface, the patient interface being a face mask, nasal mask, endotracheal tube or tracheostomy interface.

In one configuration, the system can include a humidifier configured to humidify the gas flow to the patient.

In one configuration, the controller is configured to reduce power to the humidifier when the patient is disconnected.

In one configuration, the controller is configured to turn off power to the humidifier when the patient is disconnected. In one configuration, the humidifier includes a heater plate and a humidification chamber. The chamber is positioned over the heater plate when in the operational configuration. The controller is configured to turn off power to the heater plate if the patient is detected as disconnected. This saves battery power when the device is running on batteries. Turning off the power also reduces overheating or damage to the chamber due to prolonged heating. Additionally, it helps to save the state of the heater plate and chamber. Further, turning off the power to the heater plate reduces the heating and therefore the potential for increasing the enthalpy of the gas delivered to the patient, thereby reducing the amount of heat in the humidification chamber.

In one configuration, the system can include a patient breathing conduit having a heating element configured to heat the gas flow to the patient. The heating element can be a heater wire. The heater wire can be embedded in the wall of the conduit and can be helically wound. Alternatively, the heater wire can be positioned within the lumen of the conduit.

In one configuration, the controller is configured to reduce power to the heating element of the patient breathing conduit when the patient is disconnected. This is advantageous as it reduces the likelihood of overheating of the breathing conduit or damage to the conduit from overheating. Reducing or turning off power to the conduit heating element (eg, heater wire in the conduit) can also reduce or prevent excessive enthalpy of the gas.

In one configuration, the controller is configured to turn off power to the heating element of the patient breathing conduit when the patient is disconnected. Turning off the power has advantages similar to those described above.

In one configuration, the system can include a display configured to receive and display information from one or more processors related to whether a patient is connected to the system.

In one configuration, determining patient disconnection from and/or connection to a respiratory system configured to provide respiratory therapy to a patient and also configured to provide information related to the patient's breathing. A method of doing is receiving, using a controller of a respiratory device, data for a first parameter representing gas flow or performance of a component of the device, wherein the first parameter is indicative of patient respiration. determining a correlation value for the data of the first parameter by analyzing trends in the data; and using the correlation value to determine that the patient is connected to the patient interface of the system. can be done.

In one configuration, determining can include evaluating the correlation value for a recent subset of data for the first parameter.

In one configuration, the method includes selecting the size of the subset such that frequencies within the typical breathing frequency range provide higher correlation than other frequencies above the typical breathing frequency range. can be done.

In one configuration, the size of the subset can be selected such that the subset contains data from a predetermined time span.

In one configuration, determining a correlation value can include analyzing a correlation between the first parameter data and one or more feature vectors.

In one configuration, the method may further include filtering the correlation values over time to provide filtered correlation values.

In one configuration, if the filtered correlation value exceeds a first threshold, it can be determined that the patient is connected to the patient interface.

In one configuration, it can be determined that the patient is connected to the patient interface if the filtered correlation value is above the second threshold for a certain amount of time.

In one configuration, the first threshold can exceed the second threshold.

In one configuration, the patient may be determined to be disconnected if the filtered correlation value is below a third threshold once determined to be connected.

In one configuration, a patient may be determined to be disconnected if, once determined to be connected, the filtered correlation value is below a fourth threshold for a certain amount of time.

In one configuration, the third threshold can be below the fourth threshold.

In one configuration, the fourth threshold can be equal to the second threshold. In one configuration, the fourth threshold can be below the second threshold.

In one configuration, if the patient has not yet been assumed to be connected and the filtered correlation value is between the first and second thresholds for less than a certain amount of time, the patient is It can be determined that a connection is in progress.

In one configuration, the patient may be determined to be disconnected if the correlation value falls below a second threshold once it is determined to be connected.

In one configuration, if the patient has not yet been assumed to be uncoupled and the filtered correlation value is between the third and fourth thresholds for less than a certain amount of time, the patient is It can be determined that disconnection is in progress.

In one configuration, it can be determined that the patient is connected if the correlation value exceeds a fourth threshold once it is determined to be disconnected.

In one configuration, the method may further include using the determination of whether the patient is connected to determine whether to display certain parameters.

In one configuration, the method may further include receiving an estimate of the patient's respiration rate and displaying the respiration rate estimate if the patient is determined to be connected.

In one configuration, the method may further include synchronizing delivery of gas by the device with patient respiration if the patient is determined to be connected.

In one configuration, the method may further include logging the time of each patient connection status.

In one configuration, the method may further include generating an alarm when the patient is disconnected.

In one configuration, the method may further include generating an alarm immediately after the patient is disconnected.

In one configuration, the method may further include generating an alarm following a preset time period after the patient has been disconnected.

In one configuration, the preset time can be from about 10 seconds to about 10 minutes.

In one configuration, the preset time can be from about 30 seconds to about 5 minutes.

In one example, the preset time can be from about 1 minute to about 2 minutes.

In one configuration, the method may further include outputting an alert through a nurse call port.

In one configuration, the method may further include accompanying the alert with the device providing the user with an option to confirm whether the patient is still connected.

In one configuration, the method may further include overriding the determination that the patient is disconnected using the option to check if the patient is still connected.

In one configuration, the method may further include suspending recording of certain patient parameters only when the patient is disconnected.

In one configuration, patient parameters can include oxygen efficiency.

In one configuration, oxygen efficiency can be based on _SpO2 and _FdO2 .

In one configuration, the device may comprise a make-up gas inlet and a valve, and the method may further include the valve being adjusted by the controller to regulate the flow of make-up gas through the make-up gas inlet. can.

In one configuration, the method may further include the controller closing the valve when the patient is disconnected.

In one configuration, the method may further include a controller controlling the flow generator to achieve the flow rate, the controller adjusting the flow rate when the patient is disconnected.

In one configuration, adjusting the flow rate can include reducing the flow rate.

In one configuration, adjusting the flow rate can include increasing the flow rate.

In one configuration, the increase in flow rate can continue for an initial period.

In one configuration, the initial period of time can be from about 10 seconds to about 10 minutes.

In one configuration, the initial period of time can be from about 30 seconds to about 5 minutes.

In one configuration, the initial period of time can be from about 1 minute to about 2 minutes.

In one configuration, the method may further include the controller reducing the flow rate when it is determined that the patient is still disconnected after the initial period.

In one configuration, the first parameter data can include the absolute value of the first parameter. In one configuration, the first parameter data can include changes in the first parameter.

In one configuration, the method may further comprise determining the change by subtracting the target value of the first parameter from the measured value of the first parameter.

In one configuration, the method may further comprise determining the change by subtracting the estimated influence of the second parameter from the measured value of the first parameter.

In one configuration, the first parameter may be flow rate. In one configuration, the first parameter can be pressure.

In one configuration, the second parameter may be motor speed. In one configuration, the second parameter can be pressure.

In one configuration, the system can be an unsealed system.

In one configuration, the system can be configured to provide nasal high flow therapy.

In one configuration, the system can include a patient interface, the patient interface being a nasal cannula or tracheostomy interface.

In one configuration, the system can be a closed system.

In one configuration, the system can include a patient interface, the patient interface being a face mask, nasal mask, endotracheal tube or tracheostomy interface.

In one configuration, the system can include a humidifier configured to humidify the gas flow to the patient.

In one configuration, the method may further include the controller reducing power to the humidifier when the patient is disconnected.

In one configuration, the method may further include the controller turning off power to the humidifier when the patient is disconnected.

In one configuration, the system can include a patient breathing conduit having a heating element configured to heat the gas flow to the patient.

In one configuration, the method may further include the controller reducing power to the heating element of the patient breathing conduit when the patient is disconnected.

In one configuration, the method may further include the controller turning off power to the heating element of the patient breathing conduit when the patient is disconnected.

In one configuration, the system can include a display configured to receive and display information from one or more processors related to whether a patient is connected to the system.

In one configuration, a respiratory system that can be configured to provide respiratory therapy to a patient, the system can also be configured to provide information related to the patient's breathing, the system comprising: , a respiratory device having a controller, the controller receiving data for a first parameter representative of gas flow or performance of a component of the respiratory device, the first parameter representing patient respiration; generating flow parameter change data based on the first parameter data; selecting a portion of the flow parameter change data; and based on said portion of the flow parameter change data, instantaneous and generating a measure of patient ventilation.

In one configuration, the controller applies one or more functions to selected portions of the flow parameter change data, or applies one or more functions to selected portions of the flow parameter change data. Configurable, generating a measure of instantaneous patient ventilation can include determining an area under a curve generated by one or more functions. In one configuration, the controller can be configured to apply one or more functions to selected portions of the flow parameter change data, and generating a measure of instantaneous patient ventilation is one or finding the area under a curve generated by multiple functions. The one or more functions can be linear or non-linear lines or combinations thereof. A curve generated by one or more functions can be a straight line, a non-linear line, or a combination thereof. In one configuration, one or more functions may be applied to the flow parameter change data to output specific values such as instantaneous patient ventilation or other similar values.

In one configuration, the first parameter may indicate flow rate. In one configuration, the flow rate is the total flow rate.

In one configuration, the flow parameter change data can be generated by subtracting the target value for the first parameter from the measured value for the first parameter.

In one configuration, the controller may be further configured to receive data for a second parameter representative of the gas flow or performance of a second component of the device, the flow parameter change data being a measurement of the first parameter. It can be generated by subtracting the estimated influence of the second parameter from the value.

In one configuration, the second parameter may indicate or be the motor speed.

In one configuration, the second parameter may indicate or be pressure.

In one configuration, the flow parameter change data can be generated by subtracting the first average value of the first parameter from the second average value of the first parameter.

In one configuration, the second average value can be based on measurements of the first parameter.

In one configuration, the first average value of the first parameter may be determined by applying an ongoing filter to the first parameter.

In one configuration, the portion of flow parameter change data includes data relating to time periods within a predefined time period.

In one configuration, the portion of flow parameter change data may represent a length of time.

In one configuration, the length of time may be such that signal noise is filtered out of the measure of instantaneous patient ventilation.

In one configuration, the length of time may be such that the predicted respiratory frequency will result in an increase in the measure of instantaneous patient ventilation.

In one configuration, the length of time can range from 0.5 to 2 seconds.

In one configuration, the controller can be configured to perform a least squares fit to fit one or more functions to selected portions of the flow parameter change data.

In one configuration, the curves generated by the one or more functions may be straight lines.

In one configuration, the curves generated by one or more functions may be horizontal lines.

In one configuration, one or more functions may be algebraic functions.

In one configuration, one or more functions may be transcendental functions.

In one configuration, one or more functions can generate the best-fit line.

In one configuration, a measure of instantaneous patient ventilation can be generated based on the area under the absolute value of a curve generated by one or more functions.

In one configuration, the area under the curve can be found by finding the integral of the absolute values of the lines produced by one or more functions.

In one configuration, a method of generating a measure of instantaneous patient ventilation by a respiratory system configurable to provide respiratory therapy to a patient, the method comprising using a controller of a respiratory device to: receiving data for a first parameter indicative of the performance of a component of the gas flow or device, the first parameter being indicative of patient respiration; The method may include generating parameter change data, selecting a portion of the flow parameter change data, and generating a measure of instantaneous patient ventilation based on the portion of the flow parameter change data.

In one configuration, the method can further include fitting one or more functions to selected portions of the flow parameter change data, wherein generating a measure of instantaneous patient ventilation is performed by one Or it can involve determining the area under a curve generated by a plurality of functions. In one configuration, the method can further include applying one or more functions to the selected portion of the flow parameter change data, wherein generating a measure of instantaneous patient ventilation is It involves determining the area under a curve produced by one or more functions.

In one configuration, the first parameter may indicate or be the flow rate. In one configuration, the flow rate is the total flow rate.

In one configuration, the method can further include generating flow parameter change data, which can include subtracting a target value for the first parameter from the measured value for the first parameter.

In one configuration, the method may further comprise receiving, using the controller of the respiratory device, a second parameter data representing the flow of gas or the performance of a second component of the device, the flow parameter Generating change data can include subtracting an estimated effect of the second parameter from the measured value of the first parameter.

In one configuration, the second parameter may indicate or be the motor speed.

In one configuration, the second parameter may indicate or be pressure.

In one configuration, generating the flow parameter change data can include subtracting the first average value of the first parameter from the second average value of the first parameter.

In one configuration, the second average value can be based on measurements of the first parameter.

In one configuration, the first average value of the first parameter may be determined by applying an ongoing filter to the first parameter.

In one configuration, the portion of flow parameter change data includes data relating to time periods within a predefined time period.

In one configuration, the portion of flow parameter change data may represent a length of time.

In one configuration, the length of time may be such that signal noise is filtered out of the measure of instantaneous patient ventilation.

In one configuration, the length of time may be such that the predicted respiratory frequency will result in an increase in the measure of instantaneous patient ventilation.

In one configuration, the length of time can be 0.5-2 seconds.

In one configuration, the controller can perform a least squares fit to fit one or more functions to selected portions of the flow parameter change data.

In one configuration, the curves generated by the one or more functions may be straight lines.

In one configuration, the curves generated by one or more functions may be horizontal lines.

In one configuration, one or more functions may be algebraic functions.

In one configuration, one or more functions may be transcendental functions.

In one configuration, one or more functions can generate the best-fit line.

In one configuration, a measure of instantaneous patient ventilation can be generated based on the area under the absolute value of a curve generated by one or more functions.

In one configuration, the area under the curve can be found by finding the integral of the absolute values of the lines produced by one or more functions.

In one configuration, a respiratory system can be configured to provide respiratory therapy to a patient, the system also configured to provide information related to the patient's breathing, the system comprising a controller and the controller receives data in a first parameter representative of gas flow or performance of a component of the device, the first parameter indicative of patient respiration. generating flow parameter change data based on the first parameter data; generating a measure of patient ventilation based on the flow parameter change data; and based on the flow parameter change data and determining a patient connection based on a comparison of the measure of patient ventilation and the measure of total signal variability.

In one configuration, the first parameter may indicate or be the flow rate.

In one configuration, the flow parameter change data can be generated by subtracting the target value for the first parameter from the measured value for the first parameter.

In one configuration, the controller may be further configured to receive data for a second parameter representative of the gas flow or performance of a second component of the device, the flow parameter change data being a measurement of the first parameter. It can be generated by subtracting the estimated influence of the second parameter from the value.

In one configuration, the second parameter may indicate or be the motor speed.

In one configuration, the second parameter may indicate or be pressure.

In one configuration, the flow parameter change data can be generated by subtracting the first average value of the first parameter from the second average value of the first parameter.

In one configuration, the second average value can be based on measurements of the first parameter.

In one configuration, the first average value of the first parameter may be determined by applying an ongoing filter to the first parameter.

In one configuration, the controller may be further configured to generate a measure of instantaneous patient ventilation from the flow parameter change data, the measure of patient ventilation filtering the measure of instantaneous patient ventilation. can be generated by

In one configuration, the controller can be further configured to select a portion of the flow parameter change data.

In one configuration, the portion of flow parameter change data may represent 0.5-2 seconds.

In one configuration, a measure of instantaneous patient ventilation is obtained by fitting one or more functions to selected portions of the flow parameter change data and determining the absolute value of the curve generated by the one or more functions. It can be generated by finding the area. The one or more functions can be linear or non-linear lines or combinations thereof. A curve generated by one or more functions can be a straight line, a non-linear line, or a combination thereof. In one configuration, one or more functions may be applied to the flow parameter change data to output specific values such as instantaneous patient ventilation or other similar values.

In one configuration, the controller can be configured to perform a least squares fit to fit one or more functions to selected portions of the flow parameter change data.

In one configuration, the curves generated by the one or more functions may be straight lines.

In one configuration, the curves generated by one or more functions may be horizontal lines.

In one configuration, determining the area under the absolute value of the curve can include finding the integral of the absolute value of the curve produced by the one or more functions.

In one configuration, the controller may be further configured to generate a measure of instantaneous total signal variation from the flow parameter change data, the measure of total signal variation filtering the measure of instantaneous total signal variation. can be generated by

In one configuration, a measure of instantaneous total signal variation can be determined by taking the absolute value of the flow parameter change data.

In one configuration, a measure of instantaneous total signal variation can be obtained by taking the square of the flow parameter change data.

In one configuration, comparing the measure of patient ventilation and the measure of total signal variability can include taking a ratio of the measure of patient ventilation and the measure of total signal variability.

In one configuration, once determined to be connected, the controller can be configured to determine that the patient is disconnected if the ratio is below a connection threshold. In one configuration, once determined to be connected, the controller is configured to determine that the patient is connected if said ratio does not fall below a connection threshold.

In one configuration, once determined to be disconnected, the controller can be configured to determine that the patient is connected if the ratio exceeds a connection threshold.

In one configuration, once determined to be disconnected, the controller can be configured to determine that the patient is disconnected if the ratio does not exceed a connection threshold.

In one configuration, the controller can be configured to determine that the patient is connected if the ratio exceeds a first threshold.

In one configuration, the controller can be configured to determine that the patient is connected if the ratio exceeds a second threshold for a fixed amount of time.

In one configuration, the first threshold can exceed the second threshold.

In one configuration, the patient may be determined to be disconnected if the ratio is below a third threshold once determined to be connected.

In one configuration, the patient may be determined to be disconnected if the ratio is below a fourth threshold for a certain amount of time once determined to be connected.

In one configuration, the third threshold can be below the fourth threshold.

In one configuration, the fourth threshold can be equal to the second threshold.

In one configuration, the fourth threshold can be below the second threshold.

In one configuration, if the controller has not yet assumed that the patient is connected and the ratio is between the first and second thresholds for less than a certain amount of time, the patient is It can be configured to be determined to be connected.

In one configuration, once determined to be connected, the patient may be determined to be disconnected if the ratio is below a second threshold.

In one configuration, if the controller has not yet assumed that the patient is disconnected and the ratio is between the third and fourth thresholds for less than a certain amount of time, the patient is It can be configured to be determined to be in the process of disconnecting.

In one configuration, it can be determined that the patient is connected if the ratio exceeds a fourth threshold once it is determined to be disconnected.

In one configuration, the controller can be configured to use the determination of whether a patient is connected to determine whether to display certain parameters.

In one configuration, the controller may be configured to receive an estimate of the patient's respiration rate when it is determined that the patient is connected, and displays the respiration rate estimate.

In one configuration, the respiratory device can be configured to synchronize the delivery of gas with the patient's breathing when the patient is determined to be connected.

In one configuration, the controller can be configured to log the time of each patient connection status.

In one configuration, the respiratory device can generate an alarm when the patient is disconnected.

In one configuration, the device can generate an alarm immediately after the patient is disconnected.

In one configuration, the device can generate an alarm following a preset time after the patient has been disconnected.

In one configuration, the preset time can be from about 10 seconds to about 10 minutes.

In one configuration, the preset time can be from about 30 seconds to about 5 minutes.

In one configuration, the preset time can be from about 1 minute to about 2 minutes.

In one configuration, the alert can be output through a nurse call port.

In one configuration, the alert can be accompanied by the device providing the user with an option to see if the patient is still connected.

In one configuration, the option to check if the patient is still connected can be used to override the determination that the patient is disconnected.

In one configuration, the respiratory device may suspend recording of certain patient parameters only when the patient is disconnected.

In one configuration, patient parameters can include oxygen efficiency.

In one configuration, oxygen efficiency can be based on _SpO2 and _FdO2 .

In one configuration, the device can include a make-up gas inlet and a valve, and the valve can be adjusted by the controller to regulate the flow of make-up gas through the make-up gas inlet.

In one configuration, the controller can close the valve when the patient is disconnected.

In one configuration, the controller can control the flow generator to achieve a flow rate, and the controller can adjust the flow rate when the patient is disconnected.

In one configuration, adjusting the flow rate can include reducing the flow rate.

In one configuration, adjusting the flow rate can include increasing the flow rate.

In one configuration, the increase in flow rate can continue for an initial period.

In one configuration, the initial period of time can be from about 10 seconds to about 10 minutes.

In one configuration, the initial period of time can be from about 30 seconds to about 5 minutes.

In one configuration, the initial period of time can be from about 1 minute to about 2 minutes.

In one configuration, the controller can reduce the flow rate when it is determined that the patient is still disconnected after the initial period.

In one configuration, a method of determining patient disconnection from and/or connection to a respiratory system can be configured to provide respiratory therapy to a patient, the system providing information related to the patient's breathing. and the method includes receiving, using a controller of the respiratory device, data for a first parameter representing the flow of gas or the performance of a component of the device, comprising: generating flow parameter change data based on the first parameter data; generating a measure of patient ventilation based on the flow parameter change data; flow parameter change, wherein the parameter is indicative of patient respiration; Generating a measure of total signal variability based on the data and determining a patient connection based on a comparison of the measure of patient ventilation and the measure of total signal variability can be included.

In one configuration, the first parameter may indicate or be the flow rate.

In one configuration, generating flow parameter change data can include subtracting a target value for the first parameter from a measured value for the first parameter.

In one configuration, the method may further comprise receiving, using the controller of the respiratory device, a second parameter data representing the flow of gas or the performance of a second component of the device, the flow parameter Generating change data can include subtracting an estimated effect of the second parameter from the measured value of the first parameter.

In one configuration, the second parameter may indicate or be the motor speed.

In one configuration, the second parameter may indicate or be pressure.

In one configuration, generating the flow parameter change data can include subtracting the first average value of the first parameter from the second average value of the first parameter.

In one configuration, the second average value can be based on measurements of the first parameter.

In one configuration, the first average value of the first parameter may be determined by applying an ongoing filter to the first parameter.

In one configuration, the method may further include generating a measure of instantaneous patient ventilation from the flow parameter change data, using the controller of the respiratory device, wherein generating the measure of patient ventilation is: may include filtering the measure of instantaneous patient ventilation.

In one configuration, the method may further include using the controller of the respiratory device to select a portion of the flow parameter change data.

In one configuration, the portion of flow parameter change data may represent 0.5-2 seconds.

In one configuration, generating a measure of instantaneous patient ventilation involves fitting one or more functions to selected portions of the flow parameter change data and determining the absolute value of the curve generated by the one or more functions. It can include determining the area under the value.

In one configuration, determining the area under the absolute value of the curve generated by the one or more functions causes the controller to perform a least-squares fit to a selected portion of the flow parameter change data. Or it can involve fitting multiple functions.

In one configuration, the curves generated by the one or more functions may be straight lines.

In one configuration, the curves generated by one or more functions may be horizontal lines.

In one configuration, the area under the absolute value of the curve can be determined by finding the integral of the absolute value of the curve produced by one or more functions.

In one configuration, the method may further comprise generating, using the controller of the respiratory device, a measure of instantaneous total signal variability from the flow parameter change data; may include filtering a measure of instantaneous total signal variation.

In one configuration, generating a measure of instantaneous total signal variation can include taking the absolute value of the flow parameter change data.

In one configuration, generating a measure of instantaneous total signal variation can include squaring the flow parameter change data.

In one configuration, comparing the measure of patient ventilation and the measure of total signal variability can include taking a ratio of the measure of patient ventilation and the measure of total signal variability.

In one configuration, once determined to be connected, the patient may be determined to be disconnected if the ratio is below a connection threshold.

In one configuration, the patient can be determined to be connected if, once determined to be connected, the ratio does not fall below the connection threshold.

In one configuration, the patient can be determined to be connected if, once determined to be disconnected, the ratio exceeds a connection threshold.

In one configuration, the patient can be determined to be disconnected if the ratio does not exceed the connection threshold once determined to be disconnected.

In one configuration, the patient can be determined to be connected if the ratio exceeds a first threshold.

In one configuration, the patient can be determined to be connected if the ratio is above a second threshold for a certain amount of time.

In one configuration, the first threshold can exceed the second threshold.

In one configuration, the patient may be determined to be disconnected if the ratio is below a third threshold once determined to be connected.

In one configuration, the patient may be determined to be disconnected if the ratio is below a fourth threshold for a certain amount of time once determined to be connected.

In one configuration, the third threshold can be below the fourth threshold.

In one configuration, the fourth threshold can be equal to the second threshold.

In one configuration, the fourth threshold can be below the second threshold.

In one configuration, if the patient has not yet been assumed to be connected and the ratio is between the first and second thresholds for less than a certain amount of time, the patient is connected can be determined to be

In one configuration, once determined to be connected, the patient may be determined to be disconnected if the ratio is below a second threshold.

In one configuration, if the patient has not yet been assumed to be dissociated, and the ratio is between the third and fourth thresholds for less than a certain amount of time, the patient is dissociating. can be determined to be

In one configuration, it can be determined that the patient is connected if the ratio exceeds a fourth threshold once it is determined to be disconnected.

In one configuration, the method may further include using a controller of the respiratory device to determine whether certain parameters should be displayed based on whether a patient is connected. .

One configuration may further include using the controller of the respiratory device to receive an estimate of the patient's respiration rate if the patient is determined to be connected, and displaying the respiration rate estimate. can.

In one configuration, the method may further include using a controller of the respiratory device to synchronize the delivery of gas with the patient's breathing when the patient is determined to be connected.

In one configuration, the method may further include using the controller of the respiratory device to log the time of each patient connection status.

In one configuration, the method may further include using the controller of the respiratory device to generate an alarm when the patient is disconnected.

In one configuration, the method may further include generating an alarm immediately after the patient is disconnected.

In one configuration, the method may further include generating an alarm following a preset time period after the patient has been disconnected.

In one configuration, the preset time can be from about 10 seconds to about 10 minutes.

In one configuration, the preset time can be from about 30 seconds to about 5 minutes.

In one configuration, the preset time can be from about 1 minute to about 2 minutes.

In one configuration, the method may further include outputting an alert through a nurse call port.

In one configuration, the method may further include accompanying the alert with providing the user with an option to see if the patient is still connected.

In one configuration, the option to check if the patient is still connected can be used to override the determination that the patient is disconnected.

In one configuration, the method may further include using a controller of the respiratory device to suspend recording of certain patient parameters only when the patient is disconnected.

In one configuration, patient parameters can include oxygen efficiency.

In one configuration, oxygen efficiency can be based on _SpO2 and _FdO2 .

In one configuration, the device may comprise a make-up gas inlet and a valve, and the method may further include the valve being adjusted by the controller to regulate the flow of make-up gas through the make-up gas inlet. can.

In one configuration, the method may further include the controller closing the valve when the patient is disconnected.

In one configuration, the method may further include a controller controlling the flow generator to achieve the flow rate, the controller configured to adjust the flow rate when the patient is disconnected.

In one configuration, adjusting the flow rate can include reducing the flow rate.

In one configuration, adjusting the flow rate can include increasing the flow rate.

In one configuration, the increase in flow rate can continue for an initial period.

In one configuration, the initial period of time can be from about 10 seconds to about 10 minutes.

In one configuration, the initial period of time can be from about 30 seconds to about 5 minutes.

In one configuration, the initial period of time can be from about 1 minute to about 2 minutes.

In one configuration, the method may further include the controller reducing the flow rate when it is determined that the patient is still disconnected after the initial period.

In a further configuration, the respiratory device comprises a controller configured to determine use of the respiratory device based on the amount of time the patient is detected as connected. The controller is configured to track the amount of time the patient is detected as connected. The controller can also determine and count the number of times a patient is detected as disconnected within a predefined time period. A predefined time period can be, for example, a therapy session. The controller can be configured to send the amount of time the patient is detected as connected to a remote computing device, eg, a server. In a further configuration, the server can determine the amount of time the patient has used the respiratory device based on the amount or number of times the patient is detected as connected. The controller or server may determine that the patient is in good compliance with therapy (eg, high flow therapy) if the patient is detected as connected for a predetermined period of time. Patient detection methods can be used to determine compliance or adherence to therapy. Detection of the patient as connected can be used to determine use of the respiratory device by the patient. This usage or compliance information can be shared or accessed by medical professionals via the respiratory device or via a server.

These and other features, aspects and advantages of the present disclosure are described with reference to the drawings of some embodiments, which are intended to schematically illustrate some embodiments. , are not intended to limit the present disclosure.

1 schematically illustrates a respiratory system configured to provide respiratory therapy to a patient; FIG. 3 is a front view of an example respiratory device with a humidification chamber in place and a handle/lever raised. FIG. 3 is a top view corresponding to FIG. 2; FIG. 3 is a right side view corresponding to FIG. 2; FIG. 3 is a left side view corresponding to FIG. 2; FIG. 3 is a rear view corresponding to FIG. 2; 3 is a front left perspective view corresponding to FIG. 2; FIG. 3 is a front right perspective view corresponding to FIG. 2; FIG. FIG. 3 is a bottom view corresponding to FIG. 2; Fig. 2 shows an example configuration of air and oxygen inlet arrangements for a respiratory device; FIG. 12 illustrates another example configuration of air and oxygen inlet arrangements for a respiratory device; FIG. 12 is a cross-sectional view showing further details of the air and oxygen inlet arrangement of FIG. 11; FIG. 12 is another cross-sectional view showing further details of the air and oxygen inlet arrangement of FIG. 11; FIG. Figure 12 is a longitudinal cross-sectional view showing further details of the air and oxygen inlet arrangement of Figure 11; FIG. 3 is an exploded view of the upper and lower chassis components of the main housing of the respiratory device; FIG. 4 is a front left perspective view of the lower chassis of the main housing showing the housing that receives the monitor/sensor module subassembly; FIG. 4 is a first bottom perspective view of the main housing of the respiratory device showing the recess inside the housing for the monitor/sensor module subassembly; FIG. 10 is a second lower perspective view of the main housing of the respiratory device showing recesses for monitor/sensor module subassemblies; 1 illustrates a block diagram of a control system that interacts with and/or provides control and direction to components of a respiratory system; FIG. 2 shows a block diagram of an example controller. FIG. Fig. 3 shows a block diagram of a motor and sensor module; 4 illustrates a sensing chamber of an example motor and sensor module. 4 illustrates an example flow chart for evaluating instantaneous features for patient breath detection. FIG. 4 shows an example of determining whether flow parameter data is suitable for use in determining patient connection and/or respiration; FIG. 4 illustrates an example flow chart for modifying flow data to remove the assumed effect of motor speed. An example instantaneous signature is shown when different frequencies are evaluated (no signal noise). FIG. 11 illustrates an example flow chart for determining filtered features for patient connection determination; FIG. FIG. 11 illustrates an example flow chart for determining patient connection status using filtered features. FIG. 4 illustrates an example flow chart for generating a metric for determining patient connection to a respiratory system. FIG. 11 illustrates an example flow chart for determining patient connectivity using a patient connectivity measure. FIG. FIG. 10 illustrates another example flowchart for determining patient connectivity status using a patient connectivity measure; FIG.

Several examples are set forth below, but those skilled in the art will appreciate that this disclosure extends beyond the specifically disclosed examples and/or uses and obvious modifications and equivalents thereof. . Accordingly, it is intended that the scope of the disclosure disclosed herein should not be limited by any particular examples set forth below.

Overview of an Example Respiratory System FIG. 1 provides a schematic diagram of a respiratory system 10 . Respiratory system 10 can include a main device housing 100 . The main device housing 100 may contain a flow generator 11 which may be in the form of a motor/impeller arrangement, optionally a humidifier or humidification chamber 12, a controller 13 and a user interface 14. User interface 14 may include a display and input devices such as buttons, touch screens, touch screen and button combinations, and the like. Controller 13 may include one or more hardware and/or software processors, including but not limited to, operating flow generator 11 to generate a flow of gas for delivery to the patient; operating the humidifier or humidification chamber 12 (if present) to humidify and/or heat the respiratory system 10 and providing user input from the user interface 14 for reconfiguration and/or user-defined operation of the respiratory system 10 It can be configured or programmed to control components of the system, such as receiving and outputting information (eg, on a display) to a user. A user may be a patient, a medical professional, the system 10, or the like.

With continued reference to FIG. 1 , a patient breathing conduit 16 can be coupled to the gas outlet 21 in the main device housing 100 of the respiratory system 10 , the patient breathing conduit 16 being a nasal outlet with a manifold 19 and nasal prongs 18 . It can be coupled to patient interface 17 such as a non-sealing interface such as a cannula. Patient breathing conduit 16 may also be coupled to a face mask, nasal mask or nasal pillow mask, endotracheal tube, tracheostomy interface, or the like.

The gas flow may be generated by flow generator 11 and humidified prior to delivery to the patient through patient breathing conduit 16 and through patient interface 17 . Controller 13 controls flow generator 11 to generate a desired flow rate of gas and/or operates one or more valves to control the mixture of air and oxygen or other breathable gas. can be controlled. The controller 13 can control heating elements, if present, in the humidification chamber 12 to heat the gas to the desired temperature to achieve the desired level of temperature and/or humidity for delivery to the patient. The patient breathing conduit 16 may have a heating element 16a, such as a heater wire, that heats the gas stream flowing therethrough to the patient. Heating element 16 a may also be under control of controller 13 .

System 10 may use ultrasonic transducers, flow sensors such as thermistor flow sensors, pressure sensors, temperature sensors, humidity sensors or other sensors in communication with controller 13 to monitor gas flow characteristics and/or suitable System 10 can be operated to provide therapy. Gas flow characteristics include gas concentration, flow rate, pressure, temperature, humidity, and the like. Sensors 3a, 3b, 3c, 20, 25, such as pressure sensors, temperature sensors, humidity sensors and/or flow sensors, may be placed at various locations within main device housing 100, patient conduit 16 and/or patient interface 17. can be done. The controller 13 receives outputs from the sensors that help the controller 13 operate the respiratory system 10 to provide a suitable therapy, such as determining a suitable target temperature, flow rate and/or pressure for the gas flow. can be done. Providing suitable therapy can include meeting the patient's inspiratory needs.

System 10 includes a wireless data transmitter and/or receiver, or transceiver, that enables controller 13 to wirelessly receive data signals 8 from motion sensors and/or control various components of system 10 . A vessel 15 may be included. Additionally or alternatively, data transmitter and/or receiver 15 may send data to a remote server or enable remote control of system 10 . System 10 may also include wired connections, for example using cables or wires, that allow controller 13 to receive data signals 8 from motion sensors and/or control various components of system 10 . .

Respiratory system 10 may include a high flow therapy device. High-flow therapy, as discussed herein, generally refers to the flow of a targeted humidified respiratory gas through an intentionally unsealed patient interface at a flow rate generally intended to meet or exceed the user's inspiratory flow. is intended to be given its typical ordinary meaning, as understood by those skilled in the art, referring to a respiratory system that delivers Typical patient interfaces include, but are not limited to, nasal or tracheal patient interfaces. Typical flow rates for adults often range from about 15 liters/minute to about 60 liters/minute or more, but are not so limited. Typical flow rates for pediatric users (such as neonates, infants and children) can range from about 1 liter/minute per kilogram of user weight to about 3 liters/minute per kilogram of user weight or more. Many, but not limited to. High flow therapy may also include gas mixture compositions, including supplemental oxygen and/or administration of therapeutic agents. High flow therapy includes, among other common names, nasal high flow (NHF), humidified high flow nasal cannula (HHFNC), high flow nasal oxygen (HFNO), It is also often referred to as high flow therapy (HFT) or tracheal high flow (THF). For example, in some configurations, for adult patients, "high flow therapy" is about 10 liters per minute (10 LPM) or greater, such as about 10 LPM to about 100 LPM, or about 15 LPM to about 95 LPM, or about 20 LPM to about 90 LPM. or from about 25 LPM to about 85 LPM, or from about 30 LPM to about 80 LPM, or from about 35 LPM to about 75 LPM, or from about 40 LPM to about 70 LPM, or from about 45 LPM to about 65 LPM, or from about 50 LPM to about 60 LPM. can refer to the delivery of In some configurations, for neonatal, infant or pediatric patients, "high flow therapy" is greater than 1 LPM, such as from about 1 LPM to about 25 LPM, or from about 2 LPM to about 25 LPM, or from about 2 LPM to about 5 LPM, or about 5 LPM. to about 25 LPM, or about 5 LPM to about 10 LPM, or about 10 LPM to about 25 LPM, or about 10 LPM to about 20 LPM, or about 10 LPM to 15 LPM, or about 20 LPM to 25 LPM. can. A high-flow therapy device in an adult, neonatal, infant, or pediatric patient can deliver gas to the patient at a flow rate of from about 1 LPM to about 100 LPM, or any of the subranges outlined above. can.

High-flow therapy can be effective in meeting or exceeding a patient's inspiratory demand, increasing the patient's oxygenation, and/or reducing the work of breathing. Additionally, high-flow therapy can produce a flushing effect in the nasopharynx such that the anatomical dead space of the upper airway is flushed by the incoming high-flow gas flow. The flushing effect can provide a reservoir of fresh gas available for each breath while minimizing rebreathing of carbon dioxide, nitrogen, etc.

Patient interfaces used in high-flow therapy must be non-sealed to prevent barotrauma, which can include tissue damage to the lungs or other organs of the patient's respiratory system due to differences in pressure relative to the atmosphere. can be The patient interface may be a nasal cannula with a manifold and nasal prongs, and/or a face mask, and/or a nasal pillow mask, and/or a nasal mask, and/or a tracheostomy interface, or any other suitable type of patient interface. can be

2-17B illustrate example respiratory devices of respiratory system 10 having main housing 100. FIG. The main housing 100 has a main housing upper chassis 102 and a main housing lower chassis 202 . The main housing upper chassis 102 has a perimeter wall arrangement 106 (see FIG. 15). A perimeter wall arrangement defines a humidifier or humidification chamber bay 108 that receives a removable humidification chamber 300 . Removable humidification chamber 300 contains a suitable liquid, such as water, to humidify gases that can be delivered to the patient.

In the illustrated form, the peripheral wall arrangement 106 of the main housing upper chassis 102 comprises a substantially vertical left outer wall 110 oriented in the fore-and-aft direction of the main housing 100 and a substantially vertical outer wall 110 oriented in the fore-and-aft direction of the main housing 100 . A left inner wall 112 and an interconnecting wall 114 extending between and interconnecting upper ends of left inner wall 110 and left outer wall 112 may be included. The main housing upper chassis 102 includes a substantially vertical right outer wall 116 directed in the front-rear direction of the main housing 100 , a substantially vertical right inner wall 118 directed in the front-rear direction of the main housing 100 , a right inner wall 116 and a right side wall 116 . An interconnecting wall 120 extending between and interconnecting the upper ends of the outer walls 118 may also be included. Interconnecting walls 114, 120 are angled toward their respective outer edges of main housing 100, but may alternatively be substantially horizontal or angled inward.

Main housing upper chassis 102 may further include a substantially vertical rear wall 122 . An upper portion of the main housing upper chassis 102 may include a forwardly angled surface 124 . Surface 124 may have a recess 126 that receives display and user interface module 14 . The display can be configured to display the characteristics of the sensed gas in real time. The system can display the patient detection status of the patient interface. If no patient is detected, the controller may or may not output to display respiration rate values and/or other parameters. The controller may also output to display a patient not detected message at block 2708 . An example of a message may be a "--" icon. An interconnecting wall 128 may extend between and interconnect the upper end of the rear wall 122 and the rear edge of the surface 124 .

A substantially vertical wall portion 130 may extend downwardly from the front end of surface 124 . A substantially horizontal wall portion 132 may extend forward from the lower end of wall portion 130 to form a shelf. A substantially vertical wall portion 134 may extend downwardly from the front end of wall portion 132 and terminate in a substantially horizontal floor portion 136 of humidification chamber bay 108 . Together, left inner wall 112 , right inner wall 118 , wall portion 134 and floor portion 136 may define humidification chamber bay 108 . A floor portion 136 of the humidification chamber bay 108 has a recess 138 for receiving a heater arrangement, such as a heater plate 140 or other suitable heating element, for heating the liquid in the humidification chamber 300 used during the humidification process. can be done.

The main housing lower chassis 202 may be attachable to the upper chassis 102 by either suitable fasteners, such as clips, or built-in attachment features. The main housing lower chassis 202 is oriented in the fore-and-aft direction of the main housing 100 and is oriented in the fore-and-aft direction of the main housing 100 with a substantially vertical left side wall 210 adjacent to the left side wall 110 of the upper chassis 102, and A substantially vertical right side wall 216 may be included adjacent the right side wall 116 of the upper chassis 102 . Main housing lower chassis 202 may further include a substantially vertical rear wall 222 adjacent rear wall 122 of upper chassis 102 .

The lower housing chassis 202 can have a lip 242 that also forms part of a recess that abuts the lip 142 of the upper housing chassis 102 and receives the handle portion 506 of the lever 500 . Lower lip 242 may include a forwardly directed protrusion 243 that acts as a retainer for handle portion 506 of lever 500 . Instead of lever 500 , the system can have a spring-loaded guard that holds humidification chamber 300 within humidification chamber bay 108 .

The underside of lower housing chassis 202 may include a bottom wall 230 . Each interconnecting wall 214 , 220 , 228 can extend between and interconnect substantially vertical walls 210 , 216 , 222 and bottom wall 230 . The bottom wall 230 can include a grill 232 with multiple apertures that allow for the evacuation of liquid in the event of leakage from the humidification chamber 300 (eg, from a spill). Bottom wall 230 may further include an elongated anterior-posterior oriented slot 234 . The slots 234 may also allow for the evacuation of liquid in the event of a leak from the humidification chamber 300 without the liquid entering the electronics housing. In the illustrated configuration, slot 234 can be wide and elongated relative to the aperture of grill 232 to maximize liquid evacuation.

As shown in Figures 17 and 18, the lower chassis 202 can have a motor recess 250 that receives a motor and sensor module. The motor and sensor modules may be non-removable from the main housing 100 . The motor and sensor modules may be removable from the main housing 100 as shown in FIGS. 17 and 18. FIG. A recessed opening 251 may be provided in the bottom wall 230 adjacent its trailing edge for receiving a motor/sensor module. Integral with bottom wall 230 of lower chassis 202 is formed a continuous gas impermeable uninterrupted perimeter wall 252 which may extend outwardly from the perimeter of opening 251 . A rearward portion 254 of the peripheral wall 252 has a first height and a forward portion 256 of the peripheral wall 252 has a second height that is greater than the first height. A rear portion 254 of peripheral wall 252 terminates in a substantially horizontal step 258 which further terminates in an upper secondary rear portion 260 of peripheral wall 252 . A front portion 256 and an upper auxiliary rear portion 260 of the perimeter wall 252 terminate in a ceiling 262 . All of the walls and ceiling 262 may be continuous, gas impermeable, and uninterrupted, except for the gas passages. Accordingly, the entire motor recess 250 can be gas impermeable and uninterrupted, except for the gas flow paths.

A motor and sensor module may be insertable into recess 250 and attachable to lower chassis 202 . When the motor and sensor modules are inserted into lower chassis 202, gas flow tube 264 may extend through lower extension tube 133 and be sealed with a soft seal.

Humidification chamber 300 may be fluidly coupled to apparatus 10 in a linear sliding motion in a direction from a location at the front of housing 100 toward the rear of housing 100 and rearward into chamber bay 108 of humidification chamber 300 . can. A gas outlet port 322 may be in fluid communication with the motor.

A gas inlet port 340 (humidified gas return) as shown in FIG. 8 can include a removable L-shaped elbow. The removable elbow can further include a patient exit port 344 that couples to the patient conduit 16 that delivers gas to the patient interface. Gas outlet port 322 , gas inlet port 340 and patient outlet port 344 are each sealed with an O-ring seal, T-seal or the like to provide a sealed gas passageway between apparatus 10 , humidification chamber 300 and patient conduit 16 . of soft seals.

Humidification chamber gas inlet port 306 can be complementary to gas outlet port 322 and humidification chamber gas outlet port 308 can be complementary to gas inlet port 340 . The axes of those ports can be parallel to each other to allow humidification chamber 300 to be inserted into chamber bay 108 in a linear motion.

The respiratory device includes air and oxygen in fluid communication with the motor such that the motor can deliver air, oxygen (or an alternative auxiliary gas), or mixtures thereof, to the humidification chamber 300 and thereby to the patient. It can have an oxygen (or alternative auxiliary gas) inlet. As shown in FIG. 10, the device can have a combined air/oxygen (or alternative auxiliary gas) inlet arrangement 350. FIG. This arrangement can include a coupled air/oxygen port 352 into the housing 100 , a filter 354 and a cover 356 with hinges 358 . A gas tube may also extend laterally or in another suitable direction and be in fluid communication with a source of oxygen (or alternative auxiliary gas). Port 352 may be fluidly coupled to motor 402 . For example, port 352 can be coupled to motor/sensor module 400 via a gas flow path between port 352 and an inlet aperture or port of motor and sensor module 400 (which also leads to the motor). .

The device enables a motor to deliver air, oxygen (or an alternative auxiliary gas), or suitable mixtures thereof, to the humidification chamber 300 and thereby to the patient, FIGS. 11-14. can have the arrangement shown in This arrangement may include an air inlet 356' in the rear wall 222 of the lower chassis 202 of the housing 100. The air inlet 356' comprises a rigid plate with a suitable grilling arrangement of apertures and/or slots. Sound deadening foam may be provided on the inner surface of the plate adjacent to the plate. Positioned within main housing 100 adjacent air inlet 356 ′ is air filter box 354 ′, which delivers filtered air to the motor via air inlet port 404 of motor/sensor module 400 . A port 360 may be included. Air filter box 354' may include filters configured to remove particles (eg, dust) and/or pathogens (eg, viruses or bacteria) from the gas stream. A soft seal, such as an O-ring seal, can be provided between the air outlet port 360 and the air inlet port 404 to seal between these components. The device may include a separate oxygen inlet port 358' positioned at the rearward end adjacent one side of the housing 100, the oxygen port 358' being a tank or source of piped oxygen, or the like. , for receiving oxygen from an oxygen source. Oxygen inlet port 358 ′ is in fluid communication with valve 362 . Valve 362 may preferably be a solenoid valve that allows control of the amount of oxygen added to the gas stream delivered to humidification chamber 300 . Oxygen port 358' and valve 362 can be used with other auxiliary gases to control the addition of other auxiliary gases to the gas stream. Other auxiliary gases can include any one or more of a number of gases useful in gas therapy, including but not limited to heliox and nitric oxide.

As shown in FIGS. 13-16, the lower housing chassis 202 can include suitable electronic circuit boards, such as a sensing circuit board. An electronic circuit board may be positioned adjacent the respective outer sidewalls 210 , 216 of the lower housing chassis 202 . The electronic circuit board may contain or be in electrical communication with any suitable electrical or electronic components such as, but not limited to, microprocessors, capacitors, resistors, diodes, operational amplifiers, comparators and switches. A sensor can be used with an electronic circuit board. A component of the electronic circuit board (such as but not limited to one or more microprocessors) can act as the controller 13 of the device.

One or both of the electronic circuit boards are in electrical communication with the electrical components of the device 10, including the display unit and user interface 14, motors, valves 362 and heater plate 140 to operate the motors to provide the desired flow rate of gas. , the humidification chamber 300 can be operated to humidify and heat the gas stream to an appropriate level, and an appropriate amount of oxygen (or an appropriate amount of an alternative auxiliary gas) can be supplied to the gas stream.

An electronic circuit board may be in electrical communication with a connector arrangement 274 protruding from the rear wall 122 of the upper housing chassis 102 . Connector arrangement 274 may be coupled to alarm devices, pulse oximetry ports and/or other suitable accessories. The electronic circuit board may also be in electrical communication with an electrical connector 276, which may also be provided on the rear wall 122 of the upper housing chassis 102 for providing AC power or battery power to the components of the device. can.

As noted above, motion sensors, such as flow sensors, temperature sensors, humidity sensors and/or pressure sensors, may be placed at various locations within the respiratory device, patient breathing conduit 16 and/or cannula 17, as shown in FIG. can do. An electronic circuit board can be in electrical communication with those sensors. Outputs from the sensors can be received by the controller 13 to help the controller 13 operate the respiratory system 10 to provide optimal therapy, such as meeting inspiratory demand.

As outlined above, electronic circuit boards and other electrical and electronic components can be pneumatically isolated from the gas flow path to improve safety. Sealing also prevents water ingress.

Control System FIG. 19A shows a block diagram 900 of an example control system 920 (which can be the controller 13 in FIG. 1) that can detect patient conditions and control the operation of the respiratory system, including the gas source. The control system 920 can manage the flow of gas through the respiratory system as it is delivered to the patient. For example, the control system 920 can increase or decrease the flow rate by controlling the motor speed output of the blower (hereinafter also referred to as "blower motor") 930 or the output of the valve 932 of the mixer. The control system 920 can automatically determine flow rate settings or personalized values for a particular patient, as discussed below. The flow rate can be optimized by the control system 920 to improve patient comfort and therapy.

Control system 920 may generate audio 938 and/or display/visual output 939 . For example, a flow therapy device can include a display and/or speakers. The display can show the physician any warnings or alerts generated by control system 920 . The display can also show control parameters that the physician can adjust. For example, control system 920 can automatically recommend a flow rate for a particular patient. The control system 920 can also determine the patient's respiratory status, such as, but not limited to, generate the patient's respiratory rate and transmit it to the display, which will be described in more detail below.

Control system 920 can alter the heater control output to control one or more of the heating elements (eg, to maintain the temperature set point of the gas delivered to the patient). The control system 920 can also change the operation or duty cycle of the heating elements. Heater control outputs may include a heater plate control output 934 and a heated breathing tube control output 936 .

Control system 920 can determine outputs 930-939 based on one or more of the received inputs 901-916. Inputs 901-916 may correspond to sensor measurements automatically received by controller 600 (shown in FIG. 19B). Control system 920 includes, but is not limited to, temperature sensor input 901, flow sensor input 902, motor speed input 903, pressure sensor input 904, gas fraction sensor input 905, humidity sensor input 906, pulse oximeter (e.g., _SpO2 ). Sensor Inputs 907, Stored or User Parameters 908, Duty Cycle or Pulse Width Modulation (PWM) Inputs 909, Voltage Inputs 910, Current Inputs 911, Acoustic Sensor Inputs 912, Power Inputs 913, Resistance Inputs 914, _CO2 Sensor Inputs 915 and/or may receive sensor input, including spirometer input 916 . Control system 920 can receive input from a user or parameter values stored in memory 624 (shown in FIG. 19B). The control system 920 can dynamically adjust the flow rate to the patient over the time of the patient's treatment. Control system 920 can continuously sense system parameters and patient parameters. A person of ordinary skill in the art will appreciate based on the disclosure herein that any other suitable inputs and/or outputs may be used with control system 920 .

Controller FIG. 19B shows a block diagram of one embodiment of a controller 600 (which may be controller 13 of FIG. 1). Controller 600 may include programming instructions for input state detection and output state control. Programming instructions may be stored in memory 624 of controller 600 . Programming instructions may correspond to the methods, processes and functions described herein. The programming instructions may be executed by one or more hardware processors 622 of controller 600 . Programming instructions may be implemented in C, C++, JAVA, or any other suitable programming language. Some or all of the programming instruction portions may be implemented in application specific circuitry 678 such as ASICs and FPGAs.

Controller 600 may also include circuitry 628 for receiving sensor signals. The controller 600 can further include a display 630 that communicates patient and respiratory assistance system status. Display 630 may also display warnings and/or other alerts. Display 630 may be configured to display the characteristics of the sensed gas in real-time or otherwise. Controller 600 can also receive user input via a user interface, such as display 680 . A user interface may include buttons or dials. A user interface may comprise a touch screen.

Motor/Sensor Modules Described herein including, but not limited to, a humidification chamber, a flow generator, a user interface, a controller, and a patient breathing conduit configured to couple the gas outlet of the breathing system to the patient interface Any of the respiratory system features can be combined with any of the sensor modules described herein.

FIG. 20 shows a block diagram of a motor/sensor module 2000 that can be received by recess 260 in a respiratory device (shown in FIGS. 17 and 18). The motor and sensor module can include a blower 2001 that draws room air for delivery to the patient. Blower 2001 may be a centrifugal blower.

One or more sensors (eg, Hall effect sensors) can be used to measure the motor speed of the blower motor. The blower motor can include a brushless DC motor, from which motor speed can be measured without the use of a separate sensor. For example, during operation of a brushless DC motor, the back EMF can be measured from the non-energized windings of the motor, from which the motor position can be determined and used to calculate the motor speed. can be done. Additionally, the motor driver can be used to measure the motor current, which can be used with the measured motor speed to calculate the motor torque. The blower motor can include a low inertia motor.

Room air can enter room air inlet 2002 which enters blower 2001 through inlet port 2003 . Inlet port 2003 may include valve 2004 through which pressurized gas may enter blower 2001 . Valve 2004 may control the flow of oxygen (or other auxiliary gas) into blower 2001 . Valve 2004 can be any type of valve, including proportional or binary valves. In some embodiments, the inlet port does not include a valve.

The blower 2001 may operate at motor speeds greater than 1,000 RPM and less than 30,000 RPM, greater than 2,000 RPM and less than 25,000 RPM, greater than 3,000 RPM and less than 24,000 RPM, or any of the values described above. can work. Operation of blower 2001 mixes gases entering blower 2001 through inlet port 2003 . Since mixing requires energy, the use of blower 2001 as a mixer can reduce the pressure drop inherent in systems with separate mixers, such as static mixers with baffles.

Mixed air can exit blower 2001 through conduit 2005 and enter flow path 2006 within sensor chamber 2007 . Within sensor chamber 2007, a sensing circuit board comprising sensor 2008 can be positioned such that it is at least partially immersed in the gas flow. At least some of the sensors 2008 on the sensing circuit board can be positioned within the gas stream to measure gas properties within the gas stream. After passing through the flow path 2006 in the sensor chamber 2007, the gas can exit 2009 to the humidification chamber 210. FIG.

positioning the sensor 2008 downstream of the combined blower and mixer 2001 compared to systems that position the sensor upstream of the blower and/or mixer, such as measurement of gas fraction concentrations, including oxygen concentration; Measurement accuracy can be improved. Such positioning can provide repeatable flow profiles. Additionally, by positioning the sensor downstream of the combined blower and mixer, a separate mixer, such as a static mixer with a baffle between the inlet and the detection system, where detection occurs before the blower is required, avoiding the pressure drop that might otherwise occur. A mixer can create a pressure drop across the mixer. By positioning the sensing after the blower, the blower can be a mixer, a static mixer lowering the pressure, in contrast the blower raising the pressure. Also, by immersing the sensing circuit board and at least a portion of the sensor 2008 within the flow path, the accuracy of the measurement can be improved, since the sensor is immersed in the flow and the sensor is in the flow path of the gas. This is because it is under the same conditions, such as temperature and pressure at the same time, and is therefore more likely to provide a better representation of the gas flow characteristics.

Referring to FIG. 21, gas exiting the blower may enter flow path 402 within sensor chamber 400, which may be positioned within the motor and sensor module, at sensor chamber 2007 of FIG. could be. Channel 402 can have a curved shape. Channel 402 can be configured to have a curved shape without sharp turns. The channel 402 can have curved ends and more straight sections between the curved ends. The curved channel geometry allows the pressure drop in the gas flow to be reduced without reducing the sensitivity of the flow measurement by forming the measurement portion of the channel with the measurement area partially conforming to the channel. , which will be described later with reference to FIGS. 23A and 23B.

Positioning a sensing circuit board 404 with sensors such as acoustic transmitter/receivers, humidity sensors, temperature sensors, thermistors, etc. within the sensor chamber 400 such that it is at least partially submerged within the flow path 402 . can be done. By immersing the sensing circuit board and at least a portion of the sensor within the flow path, the accuracy of the measurement can be improved, since the sensor immersed in the flow is subject to the same conditions, such as temperature and pressure, at which the gas flows. This is because it is more likely to be underlaid and therefore provide a better representation of the gas flow characteristics. After the gas passes through the flow path 402 in the sensor chamber 400, it can exit to the humidification chamber.

At least two different types of sensors can be used to measure gas flow. A first type of sensor can include a thermistor, which can determine flow rate by monitoring heat transfer between the gas stream and the thermistor. A thermistor flow sensor can pass the thermistor at a constant target temperature in the flow as the gas flows around and past the thermistor. A sensor can measure the amount of power required to maintain the thermistor at the target temperature. The target temperature can be configured to be higher than the temperature of the gas flow, such that at higher flow rates more power is required to maintain the thermistor at the target temperature.

The thermistor flow sensor also maintains multiple (e.g., two, three, or more) constant temperatures at the thermistor to avoid too little or too much difference between the target temperature and the gas flow temperature. be able to. Multiple different target temperatures allow the thermistor flow sensor to be accurate over a wide temperature range of gases. For example, the thermistor circuit may be configured for two different target temperatures such that the temperature of the gas stream is always within a certain range (e.g., not too close and not too far) to one of the two target temperatures. It can be configured to be able to switch between The thermistor circuit can be configured to operate at a first target temperature of about 50°C to about 70°C, or about 66°C. The first target temperature can be associated with a desired flow temperature range of about 0°C to about 60°C or about 0°C to about 40°C. The thermistor circuit can be configured to operate at a second target temperature of about 90.degree. C. to about 110.degree. C. or about 100.degree. The second target temperature can be associated with a desired flow temperature range of about 20°C to about 100°C or about 30°C to about 70°C.

The controller can be configured to adjust the thermistor circuit to change between at least a first target temperature mode and a second target temperature mode by connecting or bypassing a resistor in the thermistor circuit. . The thermistor circuit may be arranged as a Wheatstone bridge configuration with a first voltage divider arm and a second voltage divider arm. A thermistor can be located in one of the voltage divider arms. More details of thermistor flow sensors are described in PCT Application No. PCT/NZ2017/050119, filed September 3, 2017, which is incorporated herein by reference in its entirety.

A second type of sensor can include an acoustic sensor assembly. Acoustic sensors, including acoustic transmitters and/or receivers, can be used to measure the time-of-flight of acoustic signals that determine gas velocity and/or composition that can be used in flow therapy devices. In one ultrasonic sensing topology (including an ultrasonic transmitter and/or receiver), a driver causes a first sensor, such as an ultrasonic transducer, to generate ultrasonic pulses in a first direction. A second sensor, such as a second ultrasonic transducer, receives this pulse and provides a time-of-flight measurement of the pulse between the first and second ultrasonic transducers. This time-of-flight measurement can be used by the respiratory system's processor or controller to calculate the speed of sound in the gas flow between the ultrasonic transducers. Pulses in a second direction opposite the first direction can be transmitted by the second sensor and received by the first sensor to provide a second measure of time of flight, such as gas flow rate or velocity. can be determined. In another acoustic sensing topology, an acoustic pulse transmitted by an acoustic transmitter such as an ultrasonic transducer can be received by an acoustic receiver such as a microphone. More details of acoustic flow sensors are described in PCT Application No. PCT/NZ2016/050193, filed December 2, 2016, which is incorporated herein by reference in its entirety.

Readings from both the first type sensor and the second type sensor can be combined to obtain a more accurate flow measurement. For example, a pre-determined flow rate and one or more outputs from one of the types of sensors can be used to determine the current predicted flow rate. Then, one or more outputs from the other of the first type sensor and the second type sensor can be used to update the predicted current flow rate to calculate the final flow rate.

Exemplary Patient Detection Process As described above, when a patient is breathing through their nose into the patient interface of the respiratory system, the flow resistance fluctuations caused by inspiration and expiration cause respiratory signals to shift in flow rate or other flow parameters. detected. The patient may be disconnected from the respiratory system such that there is no respiratory signal in the gas flow parameters.

Whether the breathing system is patient connected or disconnected, such as using a patient connection decision to help the controller determine whether the dominant frequency of the frequency analysis of the gas flow parameters is the respiration rate. It may be advantageous to be able to determine Detecting patient disconnection may also have other applications, which are described in more detail below. In addition to determining whether the patient is connected to or disconnected from the respiratory system, whether the patient was previously connected to the respiratory device and is in the process of disconnecting from the respiratory device, or It may also be useful to know if you have been previously disconnected from a respiratory device and are in the process of connecting to a respiratory device.

The processes disclosed herein evaluate time-domain features of flow parameter data to determine whether the patient is connected or disconnected. Additionally, the process may classify the patient connection status into one of four categories: Disconnected, Connected, Connected, or Disconnected.

A flow rate or other gas flow parameter signal can be provided through a preprocessing step. This step causes the controller to determine whether the gas flow parameters are suitable for use in determining patient connection and/or whether the flow parameter signals supplied to the patient connection detection process Some features can be removed from the flow parameters so that any effect that one's breath is having on the gas flow parameters (flow rate, pressure, etc.) can be better represented. Details of the preprocessing steps are described in more detail below with reference to Figures 23A-23D.

Instantaneous and Filtered Feature Determination As described above, when a patient is connected to a respiratory system and breathing through a patient interface, variations in preprocessed flow or other flow parameter data are random. is assumed to consist of uncorrelated noise and correlated respiratory signals generated by the patient. As shown in FIG. 22, the process may begin at step 2202 with the controller receiving flow parameter data (such as raw data). In decision step 2204, the controller may perform preprocessing steps, for example, by determining whether the flow parameter data is or is suitable for use. If the data is not suitable for use, the controller may discard the data at step 2206 and return to step 2202 .

Figures 23A-23C illustrate an example process for determining suitability of data. The flow parameter can be flow rate. The flow parameter can also be pressure, or other types of parameters disclosed herein. The flow parameter data may be absolute values of gas flow parameters. Alternatively, the flow parameter data can be changes in gas flow parameters. This change can be determined by subtracting the target value of the gas flow parameter from the measured value of the gas flow parameter. The change can also be determined by subtracting the estimated effect of the second gas flow parameter from the measured value of the first gas flow parameter. Changes can be calculated after determining that the flow parameter data is suitable for use. In one configuration, changes can be calculated even before determining that the flow parameter data is suitable for use.

As shown in FIG. 23A, at step 2322, the controller may receive second flow parameter data that is of a different type than the first flow parameter data, such as the flow parameter data received at step 2202 of FIG. . The second parameter is presumed to influence the first parameter. For example, motor speed, pressure and/or oxygen flow or concentration may have an effect on gas flow that is separate from the effect of patient breathing on gas flow. At decision step 2324, the controller may determine whether the assumed effects are valid. For example, an assumed impact may be valid if it is greater than a minimum threshold. If not valid, it may be difficult to accurately predict the effect of the second parameter on the first parameter, such as because the assumed effect is below a minimum threshold. Accordingly, at step 2328 the controller may determine that the first parameter data, which may be the flow parameter data received at step 2202 of FIG. 22, is not suitable for use and may discard the first parameter data. good too. If the assumed impact is valid, such as by being greater than the minimum threshold, then in step 2326 the controller can determine that the first parameter data is suitable for use.

In the process of Figures 23B and 23C, a first parameter can include flow data and a second parameter can include motor speed, oxygen flow rate and/or oxygen concentration. In some configurations, the processes of Figures 23B and 23C can be performed together to determine if the flow parameter data is suitable for use. At step 2340 of FIG. 23B, the controller may receive motor speed data. The motor must be running fast enough to identify the patient's breath in the flow data. If the motor speed is too low, the effect of motor speed on flow data (such as flow rate data) may not be accurately predicted. Accordingly, at step 2342, the controller can compare the motor speed to a minimum motor speed threshold. If the motor speed is below the threshold, then in step 2344 the controller may deem the flow parameter data to be inappropriate and may discard some or all of the flow parameter data. If the motor speed is above the threshold, then at step 2346 the controller can calculate the recent change in motor speed. Changes in motor speed can result in changes in flow parameters, making it more difficult to identify patient breathing in flow parameter data. Although the effects of motor speed can be removed from the flow parameter data to some extent, larger changes in motor speed can make the data too unreliable for identifying patient respiration. Accordingly, at step 2348 the controller may apply a moving filter to the relative change in motor speed to produce a first value representing the most recent relative change in motor speed. At decision step 2350, the controller may compare the first value to a first threshold. If the first value exceeds the first threshold, the controller may consider the flow parameter value to be inappropriate and at step 2344 the flow data point may be discarded. If the first value is below the first threshold, the controller may consider the flow parameter value suitable at step 2345 .

Flow parameters (such as flow rate) can also be affected by the flow rate or concentration of make-up gas from a make-up gas source, such as oxygen from a make-up oxygen source. Although FIG. 23C is shown using oxygen as an example, the steps performed with respect to the flow rate or concentration of oxygen are also performed for the flow rate or concentration of any other make-up gas mixed with ambient air. can do. At step 2352, the controller may receive oxygen flow data or oxygen concentration data. At step 2354, the controller may calculate recent changes in oxygen flow or oxygen concentration. If the oxygen flow rate or concentration changes, the resulting change in total flow rate can make it more difficult to identify the patient's breath in the flow signal or other flow parameter signal. Accordingly, in step 2356, the controller may apply a moving filter to changes in oxygen concentration of gas or oxygen flow to generate a second value representing recent changes in oxygen concentration or flow. At decision step 2358, the controller may compare the second value to a second threshold. If the second value exceeds the second threshold, the controller may determine that the flow parameter value is inappropriate and at step 2360 the flow parameter data point may be discarded. If the second value is less than the threshold, then at step 2362 the controller may consider the flow parameter data suitable.

Either oxygen (or other make-up gas) concentration data or oxygen (or other make-up gas) flow rate data can be used for the above determination. Oxygen concentration data can be determined using one or more sensors within the respiratory device, such as an ultrasound sensor. The oxygen flow rate from the oxygen source can be determined by an oxygen flow sensor located downstream of the oxygen source.

As noted above, the flow rate (or any other flow parameter data) may be modified to remove motor effects (or other factors such as oxygen concentration or flow rate) if the controller deems the data suitable. Modification is also possible. Modifying the gas flow parameters can include removing the assumed effects of other variables (such as motor speed) from the gas flow parameters. This assumed effect is valid only if the gas flow parameter data meet certain criteria. As noted above, data may be discarded if these criteria are not met.

FIG. 23D shows an example process for modifying flow data to remove the effects of motor speed. Motor effects can be estimated using motor speed and flow conductance. At step 2380, the controller can measure the instantaneous flow conductance. Flow conductance is approximately constant over time and can therefore be estimated using a low pass filter. The controller measures the instantaneous flow conductance at each iteration using the current motor speed and the measured flow rate. At step 2382, the controller filters the instantaneous flow conductance to obtain a filtered flow conductance.

At decision step 2384, the controller may compare the instantaneous flow conductance to the filtered flow conductance to determine if the difference is significantly different. If the difference is significant, something may have changed the physical system, such as a cannula being attached or removed. At decision step 2386, the instantaneous flow conductance can be compared to the filtered flow conductance by taking the difference between the two variables and comparing it to a minimum threshold. If the difference exceeds the threshold, the difference is deemed significant and the controller may reset the filtered flow conductance at step 2388 . A reset allows the device to quickly adjust its estimate of flow conductance when the cannula is attached to and removed from the patient.

At step 2390, the controller may also change the filter coefficients of the filtered flow conductance calculation based on the difference between the instantaneous flow conductance and the filtered flow conductance. This allows the filtered flow conductance to change more quickly when the variability in flow conductance is high, such as when the cannula is first attached. The controller can then return to step 2380 to begin a new iteration of the process.

If the difference does not exceed the threshold, the difference is considered insignificant and the controller can estimate the motor's effect on flow in step 2392 . The controller can use the filtered flow conductance and motor speed to output an influence value. At step 2394, that value can be subtracted or otherwise removed from the flow data to arrive at the preprocessed flow data. Preprocessed flow data can more accurately represent the patient's respiratory flow (although preprocessed flow data can still contain signal noise).

The controller can also track recent changes in flow conductance. Changes can be tracked by adding the difference of at least two instantaneous flow conductance values to a cumulative sum that decreases over time. The decaying cumulative sum is filtered to obtain a filtered recent change in flow conductivity. Filtered recent changes in flow conductance can be used along with preprocessed flow data in a further part of the frequency analysis algorithm.

Returning to FIG. 22, if the flow parameter data is suitable for use, at step 2208 the controller can evaluate the instantaneous characteristics of the recent data, which indicates whether the recent data has trends. It can be done by analyzing whether The time scale of recent data is, for example, less than the minimum predicted or typical breathing period, preferably between the minimum predicted or typical breathing period and the minimum predicted or typical breathing period. /4, or half the minimum predicted or typical breathing period to 1/4 the minimum predicted or typical breathing period, or preferably the minimum predicted or typical breathing period or, more preferably, less than a quarter of the minimum predicted or typical respiratory period. The evaluation can be done using two vectors, and the instantaneous feature is a measure of how well recent data points correlate with one or a combination of the two vectors. The evaluation can also be done using a single vector or more than two vectors.

When the patient is not breathing through the patient interface, random fluctuations in the preprocessed flow data can be less correlated with one or both of the two vectors than when the patient is breathing through the patient interface. have a nature. Furthermore, higher frequency data may be less correlated than lower frequency data because the period of data evaluated has multiple oscillations of said higher frequency. Signals that may result in high correlation (and therefore large instantaneous features) are low frequency signals, such as patient respiratory signals.

FIG. 24 shows an example of instantaneous features when different frequencies of data (which may contain sinusoids) are evaluated (without signal noise). Shaded area 2402 represents possible values of the instantaneous feature (due to different phases of the sine wave). Solid line 2404 shows the average of the instantaneous features for that frequency. With continued reference to 22, in decision step 2210, the controller determines whether the instantaneous feature exceeds a certain instantaneous feature threshold. In a configuration such as that shown in FIG. 24, the threshold is shown as dashed line 2406 .

In one configuration, sinusoidal waves with frequencies less than 60 min ⁻¹ may have an instantaneous feature close to unity. This frequency can be largely correlated to the typical respiratory frequency of a patient, such as an adult patient. The respiratory signal can be decomposed into a fundamental (breathing) frequency and harmonics. Harmonics typically decrease with harmonic order (e.g., the first harmonic has a smaller frequency amplitude than the fundamental frequency, the second harmonic has a smaller frequency amplitude than the first harmonic, etc.). have). All of these harmonics contribute to the instantaneous feature with the highest amplitude, ie the fundamental frequency amplitude that has the most influence. In some configurations, the threshold may be lower than 1 (such as about 0.4 in FIG. 24), so that frequencies between 60 and 120 min ⁻¹ may also exceed the threshold. These frequencies can still be caused by the patient's breathing, especially in infants. The relatively high frequencies mentioned above typically do not produce transient features above the threshold.

Returning to FIG. 22, if the instantaneous characteristic is above the threshold, then in step 2212 the controller can output that a breath is detected or that the patient is connected. If the instantaneous feature does not exceed the threshold, then at step 2214 the controller may output that no breaths are detected or that the patient is disconnected.

A momentary feature above a threshold momentary feature can indicate that a breathing patient is connected to the patient interface (such as by being connected to a cannula). In addition, it is also possible to filter the instantaneous features before using them to determine the patient connection status of the respiratory system in order to reduce signal noise that causes fluctuations in the instantaneous features.

As shown in FIG. 25A, two filters can be applied to the instantaneous features in the process of obtaining filtered features. The process may begin with the controller receiving flow parameter data (such as raw data) at step 2502 . In decision step 2504, the controller may perform preprocessing steps, such as by determining whether the flow parameter data is or is suitable for use. If the data is not suitable for use, the controller may discard the data at step 2506 and return to step 2502 . If the data is suitable for use, at step 2508 the controller can evaluate the instantaneous characteristics of the data.

At step 2510, the controller may apply two different filters to the instantaneous features to generate main filtered features and short filtered features, respectively. At step 2512, the controller may use the short filtered features to determine filter coefficients for the main filtered features. At step 2514, the filtered features can be used to determine patient connection status as shown in FIG. 25B. The application of two filters allows the main filtered feature to change more quickly as the instantaneous feature approaches unity, thereby making patient connection decisions faster when there is a strong respiratory signal. can be done. Furthermore, when the patient is not breathing at the patient interface (such as a cannula), the instantaneous feature drops toward zero, thereby increasing the filter coefficients for the main filtered feature and Changes in the characteristics identified can be made more gradual, thereby slowing patient connection decisions. The controller may take relatively longer time (than when the patient is connected and breathing through the patient interface) to determine that the patient is disconnected, but The time it takes to determine that a

Better to erroneously determine that the patient is connected when the patient is not connected to the respiratory system than to erroneously determine that the patient is disconnected when the patient is still connected to the system . This is in part because the algorithms that control the flow rate and/or motor speed of the respiratory device depend on the patient they are connected to to function. Falsely determining that a patient is uncoupled can prevent these algorithms from functioning when needed. This can prevent the device from synchronizing the delivery of gas with the patient's breathing and/or reduce the effectiveness of respiratory therapy. Additionally, erroneously determining that the patient is disconnected can result in discomfort due to incorrect flow rates and/or motor speeds for the patient who is still connected to the patient interface.

As shown in FIG. 26, a process can be applied to the flow parameter data to obtain a measure of patient ventilation and a measure of total signal variability. As with other processes described herein, this process begins at step 2602 with the controller receiving data for a flow parameter (which may include raw data for a first parameter or a second parameter). can start. A flow parameter may be a flow rate or a parameter indicative of a flow rate. In one configuration, flow can refer to total flow, including respiratory flow, supplemental gas flow, and the like. In one configuration, the flow parameter may be a direct measure of gas flow. The flow parameter can be pressure, motor speed, or other types of parameters disclosed herein. The flow parameter can be a parameter that measures or is indicative of pressure, motor speed, or other types of parameters disclosed herein. A flow parameter can represent the performance of a device component. In decision step 2604, the controller may perform preprocessing steps, such as by determining whether the flow parameter data is or is suitable for use. If the data is not suitable for use, the controller may discard the data at step 2606 and return to step 2602 .

If the data is suitable for use, at step 2608 the controller may generate flow parameter change data. The flow parameter change data can be determined by subtracting the target value of the flow parameter data from the measured value of the flow parameter data. Flow parameter change data can be determined by subtracting the estimated effect of the second parameter from the measured value of the first parameter. In one configuration, the first flow parameter or first parameter is a gas flow rate or a parameter indicative of a gas flow rate. In one configuration, the second flow parameter or second parameter is pressure, motor speed or another measure of flow or a parameter indicative thereof. The estimated effect of the second parameter on the first parameter can be a change in flow rate, which can be predicted based on the current value of the second parameter, such as current motor speed. This estimated effect can be assumed in the absence of noise or patient interaction. The estimated impact can be calculated using a moving average of the relationship between motor speed and flow rate, along with the current value of a second parameter, such as current motor speed, the latter being the sum of the first and second flow parameters. It can be used to characterize relationships between parameters. In one configuration, the flow parameter change data can be determined by subtracting the first average value of the flow parameter data from the second average value of the flow parameter data. The first average value can be later in time than the second average value. The first average can also be based on a longer window of data than the second average. In one configuration, the second average can be based on a longer window of data than the first average. The windows of data can be mutually exclusive in time or partially overlap in time. The windows of data can be associated with the same length of time or different lengths of time. A first average value of the flow parameter data may be determined by applying a filter or filters in progress to the flow parameter data. The first average value of flow parameter data can be constantly or continuously updated. A second average value can be based on the measurements. Flow parameter change data can be calculated after determining that the flow parameter data is suitable for use. In one configuration, the flow parameter change data can be calculated prior to determining that the flow parameter data is suitable for use.

At step 2610, the controller selects a portion of the flow parameter change data for analysis. The portion of flow parameter change data that is selected may be the most recently measured flow parameter change data or flow parameter change data that was measured at the same time as or close in time to the analysis. A portion of the flow parameter change data can relate to a time period within the predefined time period. The portion can be selected to obtain a data set representing or relating to a predetermined length of time. By selecting the portion of the processed flow parameter data associated with a longer period of time, more is extracted from the processed flow parameter data compared to selecting the portion of the processed flow parameter data associated with a shorter period of time. Noise can be reliably filtered out. However, by selecting the portion of the processed flow parameter data associated with a longer period of time, compared to selecting the portion of the processed flow parameter data associated with a shorter period of time, relatively high frequency breathing It is possible that the signal will be filtered out. Therefore, when selecting portions of processed flow parameter data that represent lengths of time, there may be a trade-off between filtering out noise and detecting or capturing instantaneous changes. . In one configuration, it may be advantageous to select portions of the processed flow parameter data representing lengths of time less than the respiratory period. In one configuration, selecting a portion of the processed flow parameter data representing a range of 0.5 to 2 seconds may cause erroneous determination of patient connection or interaction due to random noise. It can provide reliability in detecting patient interaction or connection (with speech, coughing, etc.) for most of the expected respiratory frequencies, while being of a length that makes it less sensitive. In one configuration, the selected portion of the processed flow parameter data is less than 0.5 seconds, 0.5-1, 1-1.5, 1.5-2, 2-2.5, 2.5- It can be 3, 3-3.5, 3.5-4, 4-4.5, 4.5-5, 5-5.5, 5.5-6 seconds, or greater than 6 seconds.

In one configuration, the controller selects a portion of the processed flow parameter data prior to generating flow parameter change data at step 2608 . In one configuration, the controller selects a portion (or window) of the processed flow parameter data associated with a predetermined length of time such that signal noise is filtered out from the instantaneous patient ventilation measures described below. select. In one configuration, the controller provides a predetermined length of time such that the predicted respiratory frequency, which can include all predicted respiratory frequencies, will result in an increase in the measure of instantaneous patient ventilation. Select the portion of the relevant processed flow parameter data.

At step 2612, the controller applies one or more functions to the selected portion of the flow parameter change data. The one or more functions may be polynomial (eg, constant, linear, nonlinear, quadratic, cubic, etc.), rational, square root, etc., algebraic functions. The one or more functions may be transcendental, such as exponential, hyperbolic, logarithmic, power, periodic (eg, triangular, etc.). The controller performs regression analysis, interpolation, extrapolation, linear least-squares, non-linear least-squares, global least-squares, simple linear regression analysis, robust linear simplex analysis on selected portions of the flow parameter variation data. Various linear and/or curve fitting techniques for fitting one or more functions, which can include non-limiting example techniques such as regression analysis, polynomial regression, orthogonal regression, Deming regression, linear segmented regression, regression dilution, etc. can be implemented. One or more functions, including at least those described above, can generate the curve. A curve can be a line. Lines or curves described herein may include multiple bends, vertices and/or other features. Lines described herein may be straight, angled and/or horizontal. The lines described herein may be best-fit lines.

によって表すことができ、式中、ｍは線の平均値であり、ｓは傾きであり、ｔは線形に増加する正規化された時間パラメータである。一構成では、ｔは、使用される最も古いデータ点においてマイナス１に等しく、且つ使用される最新のデータ点において１に等しい、線形に増加する正規化された時間パラメータであり得る。一構成では、コントローラは、流れパラメータ変化データの選択された部分に、水平線を当てはめることができる。水平性は、選択された部分を表すか又はそれに関連する流れパラメータ変化データの平均であり得る。たとえば、水平線は、ｍが平均値である場合、

によって表すことができる。 In one configuration, the controller can perform a linear least-squares fit, which can include fitting a linear function, such as a straight line, to selected portions of the flow parameter change data. For example, a straight line

where m is the mean value of the line, s is the slope, and t is a linearly increasing normalized time parameter. In one configuration, t may be a linearly increasing normalized time parameter equal to minus one at the oldest data point used and equal to one at the latest data point used. In one configuration, the controller can fit a horizontal line to selected portions of the flow parameter change data. Levelness may be an average of flow parameter change data representing or associated with the selected portion. For example, a horizontal line, where m is the mean,

can be represented by

At step 2614, the controller generates a measure of patient ventilation. The measure of patient ventilation can relate primarily to patient ventilation, but can contain some noise. The controller, in step 2612, generates a measure of instantaneous patient ventilation, also referred to as a flow volume parameter or volume measurement, by determining the area under the function fit to the selected portion of the flow parameter change data. can be done. In one configuration, the controller can generate a measure of instantaneous patient ventilation in step 2612 by determining the area under the curve generated by the function fitting to the flow parameter change data. In one configuration, the controller measures instantaneous patient ventilation in step 2612 by determining the area under the absolute value of the one or more functions or curves generated by the one or more functions. can be generated. This can be determined in step 2612 by taking the integral of the absolute value of the one or more functions or curves generated by the one or more functions. In one non-limiting example, this is represented by the formula shown below.

によって表すことができる。フィルタ係数は、およそ１分に関連するデータが使用されるように設定することができる。より長いフィルタ係数を使用して、患者接続の決定をより信頼性の高いものとすることができるが、その構成は、患者の接続及び切離しに反応するのにより低速である可能性がある。 A measure of instantaneous patient ventilation (V _o ) can be multiplied by 1 minute to represent patient ventilation per minute. The instantaneous patient ventilation measure can be filtered over time to produce a patient ventilation measure that can be used to determine patient connectivity. A measure of patient ventilation may be a measure of volume. A measure of patient ventilation is

can be represented by The filter coefficients can be set such that data associated with approximately one minute is used. Longer filter coefficients can be used to make the determination of patient connection more reliable, but the configuration may be slower to react to patient connection and disconnection.

At step 2616, the controller generates a measure of total signal variation. Measures of total signal variability can include noise introduced by respiratory system electronics, signal noise, environment, patient respiration, patient ventilation, patient movement, and/or other noise that may or may not come from the patient. be. The controller can generate a measure of instantaneous total signal variation from the flow parameter change data generated in step 2608 . By taking the absolute value of the flow parameter change data, the controller can generate a measure of instantaneous total signal variation, which can also be described as variation or average variation. In one non-limiting example, this is expressed in the formula below.

In one configuration, each data point to offset can be made positive by instead taking the square of the flow parameter change data. However, squaring the flow parameter change data can lead to erroneous patient connection decisions due to random outliers in the flow parameter change data. Using absolute values may be more tolerant to outliers in flow parameter change data, which may result from coughing, yawning, and the like. A measure of the instantaneous total signal variation ( _Vshort ) can be multiplied by 1 minute as well as _V0 . A measure of instantaneous total signal variation can be viewed as representing the total variation in flow parameter change data resulting from both patient signals and random noise.

によって表すことができる。フィルタ係数は、およそ１分に関連するデータが使用されるように設定することができる。より長い係数を使用して患者接続の決定をより信頼性の高いものとすることができるが、その構成は、患者の接続及び切離しに反応するのにより低速である可能性がある。一構成では、患者換気量の尺度

は、０以上であり得る総信号変動の尺度

以上であり得る。患者換気量の尺度

は、主に患者の毎分換気量に関連する可能性があり、総信号変動の尺度

は、患者の毎分換気量及びランダムノイズの両方に関連する可能性があるため、コントローラは、ステップ２６１８において、図２７及び図２８に示すように２つの値を比較することにより患者接続を決定することができる。 Similar to V _O , a measure of instantaneous total signal variation (V _short ) can be filtered over time to produce a measure of total signal variation to facilitate patient connection determination. A measure of total signal variation is

can be represented by The filter coefficients can be set such that data associated with approximately one minute is used. Longer coefficients can be used to make patient connection determinations more reliable, but the configuration may be slower to react to patient connection and disconnection. In one configuration, a measure of patient ventilation

is a measure of total signal variation that can be greater than or equal to 0

It can be more than measure of patient ventilation

may be related primarily to the patient's minute ventilation and is a measure of total signal variability

can be related to both the patient's minute ventilation and random noise, the controller determines the patient connection in step 2618 by comparing the two values as shown in FIGS. can do.

Determining Connection Status As shown in FIG. 25B, the controller uses the filtered features described above to determine four categories of patient connection status: patient disconnected from respiratory system or connecting to respiratory system. , connected, or disconnecting from the respiratory system. This evaluation can be done by comparing the main filtered features to one or more feature thresholds (such as thresholds close to 1 or slightly less than 1 as described above). To reach a decision that the patient is connected or disconnected, the main filtered features must be above or below the threshold. The threshold may be the most recent change in the main filtered feature, the sum calculated prior to the most recent change in flow conductance, and/or the feature when the signal is pure noise, i.e. the patient is not connected. It can be determined by further analysis of the value of the feature when it contains the known value of .

At decision step 2530, the controller may determine whether the patient was previously connected to the respiratory system or is in the process of disconnecting (ie, still connected). If the patient was previously connected or not in the process of disconnecting, i.e., if the patient is disconnected or in the process of connecting, then in step 2542 the controller determines that the dominant filtered feature is greater than the first threshold. Alternatively, it can be determined whether the patient has been on-line for a predetermined amount of time. If the dominant filtered feature is greater than the first threshold, or if the patient has been connected to the respiratory system for at least a predetermined amount of time, in step 2550 the controller determines that the patient is connected to the respiratory system. can do.

If the primary filtered feature is less than or equal to the first threshold and/or if the patient is not connected to the respiratory device for at least a predetermined amount of time, then in step 2544 the controller determines that the primary filtered feature is: It can be determined whether it is greater than a second threshold that is lower than the first threshold. If the dominant filtered feature is below the second threshold, then in step 2546 the controller can determine that the patient is disconnected. If the dominant filtered feature is greater than the second threshold but less than or equal to the first threshold (i.e., between the first and second thresholds), then in step 2548 the controller indicates that the patient is breathing system can be determined to be connected to.

If the patient was previously connected or is in the process of disconnecting, then at step 2532 the controller determines whether the main filtered feature is below a third threshold or whether the patient is in the process of disconnecting for a predetermined amount of time. can determine whether If the dominant filtered feature is below the third threshold, or if the patient has been dissociated for a predetermined amount of time, then in step 2543 the controller can determine that the patient is dissociated.

If the dominant filtered feature is greater than or equal to the third threshold and/or the patient is not in dissociation for a predetermined amount of time, then in step 2536 the controller determines that the dominant filtered feature is greater than or equal to the third threshold. It can be determined whether it is lower than a fourth high threshold. If the dominant filtered feature is less than the fourth threshold but greater than or equal to the third threshold (i.e., between the third and fourth thresholds), then in step 2538 the controller determines whether the patient is breathing. It can be determined that it is disconnecting from the system. If the dominant filtered feature is equal to or greater than (or higher than) the fourth threshold, then in step 2540 the controller can determine that the patient is connected.

The first and fourth thresholds may be the same or different (eg, the fourth threshold may be lower than the first threshold). The second and fourth thresholds may be the same or different (eg, the fourth threshold may be lower than the second threshold). The absolute values of the difference between the first and second thresholds and the difference between the third and fourth thresholds may be the same or different.

The process shown in FIG. 25B allows the controller to determine, for example, that the patient is still in the process of connecting or disconnecting from the respiratory system so that the main filtered features temporarily exceed the threshold by a small amount. It ensures that the patient is not determined to be connected or disconnected based on exceeding. A patient is determined to be connecting or disconnecting if the predominant filtered feature exceeds the threshold, but not by a significant amount. Furthermore, if a patient is determined to be connected or disconnected for a certain amount of time, the determination is It can switch to a connected or disconnected determination.

と総信号変動の尺度

とを使用して、患者接続ステータス、たとえば、患者が呼吸システムに接続されているか又は呼吸システムから切り離されているかを決定することができる。この決定は、
患者換気量の尺度

と総信号変動の尺度

とを比較することによって行うことができる。患者換気量の尺度

と総信号変動の尺度

とが同様である場合、コントローラは、信号変化の大部分が患者によってもたらされ、したがって、患者は接続又は連結されていると決定することができる。患者換気量の尺度

と総信号変動の尺度

とが著しく異なる（たとえば、

である）場合、コントローラは、信号変化の大部分がランダムノイズによってもたらされ、したがって、患者は接続又は連結されていないと決定することができる。 As shown in FIG. 27, the controller controls the generated patient ventilation measures described above with reference to FIG.

and a measure of total signal variation

and can be used to determine patient connection status, eg, whether the patient is connected or disconnected from the respiratory system. This decision
measure of patient ventilation

and a measure of total signal variation

This can be done by comparing the measure of patient ventilation

and a measure of total signal variation

are similar, the controller can determine that the majority of the signal changes are caused by the patient and therefore the patient is connected or coupled. measure of patient ventilation

and a measure of total signal variation

is significantly different from (for example,

), the controller can determine that most of the signal changes are caused by random noise and therefore the patient is not connected or coupled.

と総信号変動の尺度

との関係は、

と

との比（又は一部それを含むこと）によって求めることができる、患者連結尺度（σ）によって表すことができる。非限定的な例では、以下の式を使用して、患者連結尺度（σ）を計算することができる。

In one configuration, if the measure of instantaneous patient ventilation (V _o ) and the measure of total signal variation (V _short ) are similar, the controller determines that the majority of the signal variation is caused by the patient and thus A patient can be determined to be connected or coupled. In one configuration, if a measure of instantaneous patient ventilation (V _o ) and a measure of total signal variation (V _short ) are significantly different (e.g., V _short >>V _o ), the controller A large part is caused by random noise, so it can be determined that the patient is not connected or connected. measure of patient ventilation

and a measure of total signal variation

The relationship with

and

can be expressed by a patient connectivity measure (σ), which can be determined by the ratio (or partial inclusion) of In a non-limiting example, the following formula can be used to calculate the Patient Linkage Measure (σ).

を比較することによって、求めることができる。一構成では、補正係数は、患者の呼吸流の円滑さを示すものとして使用することができる。患者連結尺度（σ）は、信号対雑音比（ＳＮＲ）に関連することができる。１つの非限定的な例では、この関係は以下の式によって表すことができる。

A patient linkage measure (σ) can be determined in part by using a correction factor. A correction factor can be determined by comparing two or more measures of instantaneous patient ventilation (V _o ), each calculated differently. A correction factor is two or more measures of patient ventilation, each calculated differently

can be obtained by comparing In one configuration, the correction factor can be used as an indication of the smoothness of the patient's respiratory flow. A patient connectivity measure (σ) can be related to the signal-to-noise ratio (SNR). In one non-limiting example, this relationship can be expressed by the following equation.

The patient connectivity measure (σ) may be zero when the signal-to-noise ratio (SNR) is zero. As the signal-to-noise ratio (SNR) approaches zero, the patient connectivity measure (σ) can approach zero. The patient linking measure (σ) can be 1 when the signal-to-noise ratio (SNR) is infinite. The patient connectivity measure (σ) can approach unity as the signal-to-noise ratio (SNR) approaches infinity. A patient connectivity measure (σ) can be used to determine patient connectivity by comparing the patient connectivity measure (σ) to one or more thresholds. The controller may also alternatively compare the patient coupling measure, the correction factor, any measure of patient minute ventilation, or any combination thereof against a predetermined threshold to determine if the patient is connected to the respiratory system. It is possible to determine whether or not This combination can be based on an average value or any weighted average value. The correction factors and/or minute ventilation measures tend toward zero when the patient is disconnected and should therefore exceed a certain threshold when the patient is connected to the respiratory system.

と総信号変動の尺度

との比であり得る患者連結尺度（σ）が、接続閾値を超えるか否かを判断することができる。患者連結尺度（σ）が接続閾値を超える場合、コントローラは、ステップ２７０６において、患者が接続されていると決定する。患者連結尺度（σ）が接続閾値を超えない場合、コントローラは、ステップ２７０８において、患者が切り離されていると決定する。接続閾値は、信号対雑音比に対応する値に設定することができ、その値を上回ると、変動がすべてランダムノイズによって生成されるわけではないことを確実に想定することができる。 As shown in FIG. 27, the controller can determine at decision step 2702 whether the patient was previously connected to or disconnected from the respiratory system. If the patient was previously disconnected, then at step 2704 the controller, for example, measures patient ventilation

and a measure of total signal variation

It can be determined whether a patient connectivity measure (σ), which can be the ratio of σ, exceeds a connectivity threshold. If the patient connectivity measure (σ) exceeds the connectivity threshold, the controller determines in step 2706 that the patient is connected. If the patient connectivity measure (σ) does not exceed the connectivity threshold, the controller determines in step 2708 that the patient is disconnected. The connection threshold can be set to a value corresponding to the signal-to-noise ratio above which it can be safely assumed that the fluctuations are not all generated by random noise.

In one configuration, the connection threshold may be set to a value corresponding to a signal-to-noise ratio of 33%. In one configuration, the connection threshold may be set to a value corresponding to a signal-to-noise ratio below or above 33%. In one configuration, at step 2704, the controller may determine whether the patient connectivity measure (σ) continuously exceeds the connectivity threshold or another threshold for a set period of time. This period may be such that data for a short period of time, such as a few seconds, will decay, such as approximately 80% decay, by the end of the period. This advantageously prevents a few seconds of erroneous data from leading to an erroneous determination of patient connection.

If the patient was previously connected, at step 2710 the controller may determine whether the patient connectivity measure (σ) is below the disconnection threshold. If the patient connectivity measure (σ) is below the disconnect threshold, the controller determines in step 2714 that the patient is disconnected. If the patient connectivity measure (σ) is not below the disconnect threshold, the controller determines in step 2712 that the patient is connected. The disconnect threshold is below the connect threshold. The decoupling threshold can be set to a value that can be reliably assumed to be caused by random noise only. In one configuration, at step 2710, the controller may determine whether the patient connectivity measure (σ) is continuously below the dissociation threshold for a set period of time. This period may be such that short-term data, such as a few seconds, will decay by the end of the period. This advantageously prevents a few seconds of erroneous data from leading to an erroneous determination of patient connection.

As shown in FIG. 28, the controller uses the patient connection measure (σ) described above to determine four categories of patient connection status: patient is disconnected from the respiratory system or is connected to the respiratory system. It can be determined whether it is present, connected, or disconnecting from the respiratory system. This assessment can be made by comparing the patient linkage measure (σ), also referred to as the ratio, to one or more thresholds. To reach a decision that a patient is connected or disconnected, the patient connectivity measure (σ) must be above or below the threshold.

At decision step 2830, the controller may determine whether the patient was previously connected to the respiratory system or is in the process of disconnecting (ie, still connected). If the patient was previously connected or not in the process of disconnecting, i.e., if the patient is disconnected or in the process of connecting, then in step 2842 the controller determines that the patient connectivity measure (σ) is greater than the first threshold. Alternatively, it can be determined whether the patient has been on-line for a predetermined amount of time. If the patient connectivity measure (σ) is greater than the first threshold, or if the patient has been connected to the respiratory system for at least a predetermined amount of time, then at step 2850 the controller determines that the patient is connected to the respiratory system. can do.

If the patient connectivity measure (σ) is less than or equal to the first threshold and/or if the patient is not connected to the respiratory system for at least a predetermined amount of time, then in step 2844 the controller determines that the patient connectivity measure (σ) is: It can be determined whether it is greater than a second threshold that is lower than the first threshold. If the patient connectivity measure (σ) is less than a second threshold, then at step 2846 the controller may determine that the patient is disconnected. If the patient connectivity measure (σ) is greater than the second threshold but less than or equal to the first threshold (i.e., between the first and second thresholds), then in step 2848 the controller determines that the patient is in the respiratory system. can be determined to be connected to.

If the patient was previously connected or is in the process of disconnecting, then at step 2832 the controller determines whether the patient connectivity measure (σ) is less than a third threshold or the patient is in the process of disconnecting for a predetermined amount of time. can determine whether If the patient connectivity measure (σ) is below the third threshold, or if the patient has been dissociated for a predetermined amount of time, then at step 2834 the controller may determine that the patient is disassociated.

If the patient-linked measure (σ) is greater than or equal to the third threshold and/or if the patient is not in dissociation for a predetermined amount of time, then in step 2836 the controller determines that the patient-linked measure (σ) is greater than or equal to the third threshold. It can be determined whether it is lower than a fourth high threshold. If the patient connectivity measure (σ) is less than the fourth threshold but greater than or equal to the third threshold (i.e., between the third and fourth thresholds), then in step 2838 the controller determines that the patient is breathing. It can be determined that it is disconnecting from the system. If the patient connectivity measure (σ) is greater than or equal to the fourth threshold (or higher), then at step 2840 the controller may determine that the patient is connected.

The first and fourth thresholds may be the same or different (eg, the fourth threshold may be lower than the first threshold). The second and fourth thresholds may be the same or different (eg, the fourth threshold may be lower than the second threshold). The absolute values of the difference between the first and second thresholds and the difference between the third and fourth thresholds may be the same or different.

The process illustrated in FIG. 28 causes the patient connectivity measure (σ) to temporarily exceed the threshold by a small amount, for example, by determining that the patient is still in the process of connecting or disconnecting from the respiratory system. It ensures that the patient is not determined to be connected or disconnected based on exceeding. A patient is determined to be connecting or disconnecting if the patient connectivity measure (σ) exceeds the threshold, but not by a significant amount. Furthermore, if a patient is determined to be connected or disconnected for a certain amount of time, the determination is It can switch to a connected or disconnected determination.

The systems and methods described with reference to Figures 27 and 28 may be more reliable for determining patient connections than the systems and methods described with reference to Figures 25A and 25B.

に基づいて患者換気量の代理尺度（Ｖ）を生成することができる。別法として、コントローラは、以下の関数に表すように、患者連結尺度（σ）と総信号変動の尺度

とに基づいて、患者換気量の代理尺度（Ｖ）を生成することができる。患者の毎分換気量は、以下のように、処理済みの流れの変化の絶対を使用して、患者自身によってもたらされたこれらの変化の推定された比を考慮することによって、推定することができる。

Generating a Proxy Measure of Patient Ventilation The controller generates a measure of patient ventilation

A surrogate measure of patient ventilation (V) can be generated based on . Alternatively, the controller can combine a patient-linked measure (σ) and a measure of total signal variability as expressed in the following functions:

A surrogate measure of patient ventilation (V) can be generated based on and. The patient's minute ventilation can be estimated by using the absolute of the processed flow changes and considering the estimated ratio of these changes brought about by the patient himself, as follows: can be done.

The function used can be generated through machine learning by utilizing the measures detailed herein with actual measures of patient ventilation.

A surrogate measure of patient ventilation (V) relates the actual patient ventilation per minute as well as other factors such as the profile of the flow path and/or flow restriction in the respiratory system, such as between the cannula and the patient's nose. be able to. In one configuration, actual patient minute ventilation cannot be calculated from a surrogate measure of patient ventilation (V) alone, requiring a factor measure. In one configuration, the surrogate measure of patient ventilation (V) is converted to actual patient minute ventilation along with other factors such as flow path, flow restriction profile and/or other factors in the respiratory system. or close. Changes in the surrogate measure of patient ventilation (V) can be correlated to actual changes in patient minute ventilation for the same patient using the same nasal cannula. Thus, trends in a surrogate measure of patient ventilation (V) can be used to show similar trends in a patient's actual minute ventilation. Further, the determination of patient connection can be incorporated by analyzing trends in minute ventilation, whereby the trend in minute ventilation corresponds to the period during which the patient was determined to be connected to the patient's ventilation. Assessed using only the surrogate scale of quantity (V). A surrogate measure of patient ventilation (V) can have additional uses to aid in effective use of the respiratory system.

Applications of the Breath Detection Process Determining whether a patient is connected to a patient interface can inform the accuracy of respiration rate determination and/or for other purposes. One of the other purposes is for the process of adherence tracking. Adherence tracking is an important factor for measuring patient compliance, especially for reimbursement purposes. Adherence tracking is a compliance measure that informs users, clinicians, insurance companies, etc. whether a patient is connected and whether the patient is using the prescribed therapy as intended. is part of Due to the error on the part of patient compliance, i.e., it is better to overestimate patient compliance than to underestimate it, and at any time the patient is detected as being connected to the patient interface, therapy will not be adhered to. can be logged in the electronic memory of the respiratory device as a moment.

The respiratory device can maintain a log of the amount of time the patient has been connected to the device and/or how long the device has been on, adherence being the duration the device has been on. percentage of time. The device can log the duration of each of the patient connection status categories. Data related to adherence may be accessible through a higher level settings menu. Menus can be password encrypted and/or otherwise protected from patient access. Compliance data may be logged for transmission to a server and/or available for download by connecting the respiratory device to a second device (such as a computer or USB).

The respiratory device can generate an alarm when the patient is disconnected. The alert can occur immediately or after a preset time of determination that the patient has been disconnected. The preset time can be from about 10 seconds to about 10 minutes, or from about 30 seconds to 5 minutes, or from about 1 minute to about 2 minutes. Alerts can also be output to a nurse call port. After the alarm is generated, the device may provide the user with an option, eg, via the respiratory device's user interface, to confirm whether the patient has been disconnected from the device. If the patient is still connected to the device, the user has the option to manually override the controller's determination that the patient is disconnected. The disable option can reduce false positive detections, for example, when a patient is connected to the device but may be breathing shallowly. The device's controller can use the patient connection decision to determine whether or not to display certain parameters. For example, the controller can receive an estimate of the patient's respiration rate and can display the respiration rate estimate when the patient is determined to be connected. The controller can also cause the determination of whether the patient is connected or not to be displayed. For example, the device displays a respiratory rate estimate if the patient is determined to be connected, and a symbol that the patient connection cannot be verified if the patient is not determined to be connected and/or Notifications can be displayed. This can improve the reliability of the displayed respiration rate estimate.

The device may also attempt to synchronize gas delivery with the patient's breathing if the patient is determined to be connected. Respiratory gating has a phase that matches the phase of the patient's respiratory cycle, such as by increasing flow when the patient is inhaling and/or decreasing flow when the patient is exhaling. As such, it can include adjusting a flow source (such as a flow generator). One or more measured parameters, such as flow rate, blower motor speed and/or system pressure, can be used to determine patient respiratory cycle. Further details of respiratory gating can be found in WO2017/200394 filed May 17, 2017, which is incorporated herein by reference in its entirety.

The device can be configured to suspend recording of certain patient parameters only when the patient is disconnected. One such patient parameter can be oxygen efficiency, which is based on the patient's measured blood oxygen saturation ( _SpO2 ) value and the measured fraction of oxygen delivered to the patient ( _FdO2 ) value. can be calculated by Oxygen efficiency can also be determined based on the patient's measured SpO ₂ divided by the measured FdO ₂ . Oxygen efficiency can be determined based on the non-linear relationship between the patient's measured SpO ₂ and measured FdO ₂ . The device can implement one or more closed loop control systems that use oxygen efficiency to control gas flow. Patient disconnection detection can also feed oxygen delivery control, such as closed loop control. If the patient temporarily disconnects the patient interface, the patient's oxygen saturation may become depleted and the respiratory device controller may begin increasing the oxygen concentration in the gas mixture to be delivered to the patient. The device can automatically adjust _FdO2 to achieve a target _SpO2 value for the patient. When the patient interface is reattached to the patient, the oxygen concentration in the gas stream can be high, causing the patient's oxygen saturation to spike, which can be harmful to the patient. Patient disconnection detection can take into account the device's oxygen delivery control, whereby the controller does not initiate an increase in oxygen delivery when it is determined that the patient has disconnected from the device, or the controller does not initiate a predetermined value. The device can also be configured to close the valve to stop delivery of oxygen or other breathable gas mixed with air when it is determined that the patient has been disconnected. Closing the valve to the oxygen or other breathable gas inlet may reduce the cost of providing therapy and/or improve user safety.

Additionally or alternatively, the device reduces flow, reduces or turns off power to the heating element of the humidification chamber, and/or heats the patient breathing conduit when it is determined that the patient is disconnected. It can be configured to reduce or turn off power to the device. Noise can be reduced by reducing the flow rate. Reducing the flow rate and/or reducing or turning off the power to the heating elements of the humidification chamber and/or the patient breathing conduit can reduce the power consumption of the device, thereby reducing battery life and/or You can extend the life of the device's separate power supply. Additionally or alternatively, the device may be configured to increase the flow rate for an initial period of time once the patient is determined to be disconnected. Increased flow can improve the reliability of the patient detection process. The initial period of increased flow can be used to confirm that the patient has actually disconnected from the device, thus reducing false positives. If the controller determines that the patient is shedding at a relatively high flow rate, the device can take other actions as described above (e.g., stop some control algorithms, output an alarm, etc.). reducing flow, reducing or turning off power to heating elements in the humidification chamber and/or patient breathing conduit, etc.). The initial time period can be, for example, from about 10 seconds to about 10 minutes, or from about 30 seconds to 5 minutes, or from about 1 minute to 2 minutes. Once it is determined that the patient is reconnected to the device, the device will operate normally, such as increasing the flow rate and/or turning on power to heating elements in the humidification chamber and/or patient breathing conduit. can be resumed.

Terminology Throughout the specification and claims, unless the context clearly requires otherwise, the words "comprising, including,""comprising,including," etc. are used in contrast to exclusive or exhaustive meanings. should be construed in an inclusive sense, i.e., in the sense of "including but not limited to."

While this disclosure has been described in terms of several embodiments and examples, it will be appreciated by those skilled in the art that this disclosure may extend beyond the specifically disclosed embodiments and other alternative embodiments and/or uses and their obvious It is understood to extend to modifications and equivalents. Moreover, while several variations of embodiments of the disclosure have been shown and described in detail, other embodiments within the scope of the disclosure will be readily apparent to those skilled in the art. It is also contemplated that various combinations or subcombinations of the given features and aspects of the embodiments can be made and still fall within the scope of the disclosure. For example, features described above in connection with one embodiment can be used in different embodiments described herein, and combinations thereof still fall within the scope of the present disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined or substituted with each other to form various modes of the disclosed embodiments. Accordingly, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above. Thus, unless otherwise specified or clearly contradicted, each embodiment of the invention may include each other of the invention described herein in addition to its essential features described herein. may include one or more of the features described herein from the embodiments of

Features, materials, properties or groups described in connection with a particular aspect, embodiment or example are not inconsistent with any other aspect, embodiment or example described in this section or elsewhere herein. should be understood to be applicable only to the extent All of the features disclosed in this specification (including any appended claims, abstract and drawings) and/or all of the steps of any method or process so disclosed may be referred to as such features and/or Except combinations where at least some of the steps are mutually exclusive, they can be combined in any combination. Protection is not restricted to the details of any foregoing embodiments. Protection is granted to any novelty or any novel combination of the features disclosed herein (including any appended claims, abstract and drawings) or any manner so disclosed. or to any novel one or any novel combination of process steps.

Moreover, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Further, while features may be described above as functioning in some combination, one or more features from a claimed combination may optionally be deleted from the combination and the combination may be claimed as subcombinations or variations of subcombinations.

Further, although acts may be illustrated in the drawings or described in the specification in a particular order, such acts may be performed in the specific order shown or in sequence to achieve the desired result. It is not required that the order be performed or that all actions be performed. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional acts may be performed before, after, concurrently with, or between any of the described acts. Furthermore, in other implementations, the actions can be rearranged or reordered. Those skilled in the art will appreciate that in some embodiments, the actual steps performed in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, some of the steps described above may be removed and others may be added. Moreover, features and attributes of the specific embodiments disclosed above can be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. Also, the separation of various system components in the above-described embodiments should not be construed as requiring such separation in all embodiments, as the described components and systems are generally combined into a single product. It should be understood that they can be incorporated together or packaged into multiple products.

For purposes of this disclosure, certain aspects, advantages and novel features have been described herein. Not all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will appreciate the present disclosure for one advantage or group of advantages taught herein without necessarily attaining other advantages that may be taught or suggested herein. It will be appreciated that it can be embodied or implemented so as to achieve

Conditional language such as "can," "may," "could," etc., unless otherwise specified or understood otherwise in the context in which it is used, generally refers to a feature, It is intended to mean that elements and/or steps are included in some embodiments but not in other embodiments. Thus, such conditional language generally indicates that features, elements and/or steps are in any way essential to one or more embodiments or that one or more embodiments impose user input or instructions. The presence or absence of these features, elements and/or steps is not meant to necessarily imply logic to determine whether or not these features, elements and/or steps are included or performed in any particular embodiment.

As used herein, terms such as "approximately," "about," "generally," and "substantially" refer to a value, amount, or characteristic that is being stated. Represents a value, quantity, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” refer to less than 10%, less than 5%, less than 1%, It can refer to amounts in the range of less than 0.1%, in the range of less than 0.01%.

The scope of this disclosure is not intended to be limited by the specific disclosure of embodiments in this section or elsewhere herein, and the scope of this disclosure is not intended to be limited by It may be defined by the claims presented or hereinafter presented. Claim language should be construed broadly based on the language employed in the claims and should not be limited to the examples set forth herein or during the prosecution of this application; Examples should be construed as non-exclusive.

Claims (32)

A respiratory system configured to provide respiratory therapy to a patient, the respiratory system also configured to provide information related to the patient's breathing,
A respiratory device comprising a controller, the controller comprising:
receiving data for a first parameter indicative of gas flow or performance of a component of the device, the first parameter indicative of respiration of the patient;
generating flow parameter change data based on said data for said first parameter;
generating a measure of patient ventilation based on the flow parameter change data;
generating a measure of total signal variation based on the flow parameter change data;
determining a patient connection based on a comparison of the measure of patient ventilation and the measure of total signal variation;
A system comprising a respiratory device configured to: 2. The system of claim 1, wherein the first parameter indicates or is flow rate. 3. The system of claim 1 or 2, wherein the flow parameter change data is generated by subtracting the target value of the first parameter from the measured value of the first parameter. The controller is further configured to receive data for a second parameter representative of the gas flow or performance of a second component of the device, wherein the flow parameter change data is derived from measurements of the first parameter. 3. A system according to claim 1 or 2, generated by subtracting the estimated influence of said second parameter. 5. The system of claim 4, wherein the second parameter indicates or is motor speed. 3. A system according to claim 1 or 2, wherein said flow parameter change data is generated by subtracting a first average value of said first parameter from a second average value of said first parameter. 7. The system of claim 6, wherein said second average value is based on measurements of said first parameter. 8. A system according to claim 6 or 7, wherein said first average value of said first parameter is determined by applying an ongoing filter to said first parameter. The controller is further configured to generate an instantaneous patient ventilation measure from the flow parameter change data, wherein the patient ventilation measure is generated by filtering the instantaneous patient ventilation measure. The system according to any one of claims 1 to 8, wherein 10. The system of Claim 9, wherein the controller is further configured to select a portion of the flow parameter change data. 11. The system of claim 10, wherein said portion of said flow parameter change data represents a length of time in the range of 0.5-2 seconds. The measure of instantaneous patient ventilation fits one or more functions to the selected portion of the flow parameter change data and is below the absolute value of a curve generated by the one or more functions. A system according to any one of claims 9 to 11, generated by finding areas. 13. The system of claim 12, wherein the controller is configured to perform a least squares fit to fit the one or more functions to the selected portions of the flow parameter change data. 14. A system according to claim 12 or 13, wherein said curves generated by said one or more functions are straight lines. 14. A system according to claim 12 or 13, wherein said curve produced by said one or more functions is a horizontal line. 16. Any one of claims 12-15, wherein determining the area under the absolute value of the curve comprises finding the integral of the absolute value of the curve produced by the one or more functions. The system described in paragraph. The controller is further configured to generate a measure of instantaneous total signal variation from the flow parameter change data, the measure of total signal variation generated by filtering the measure of instantaneous total signal variation. A system according to any one of claims 1 to 16, wherein 18. The system of claim 17, wherein the measure of instantaneous total signal variation is determined by taking the absolute value of the flow parameter change data. 19. Any of claims 1-18, wherein comparing the measure of patient ventilation and the measure of total signal variation comprises taking the ratio of the measure of patient ventilation to the measure of total signal variation. The system according to item 1. 20. The system of Claim 19, wherein the controller is configured to determine that the patient is connected if the ratio exceeds a first threshold. 21. The system of claim 20, wherein the controller is configured to determine that the patient is connected if the ratio is above a second threshold for a fixed amount of time. 22. The system of claim 21, wherein said first threshold exceeds said second threshold. 23. Any one of claims 1-22, wherein the controller is configured to use the determination of whether the patient is connected to determine whether to display certain parameters. The system described in . 24. The system of claim 23, wherein the controller is configured to receive an estimate of the patient's respiration rate when the patient is determined to be connected, and displays the respiration rate estimate. A system according to any preceding claim, wherein the system is an unsealed system. 26. The system of claim 25, wherein the system is configured to provide nasal high flow therapy. The system of any preceding claim, wherein the system comprises a humidifier configured to humidify the gas flow to the patient. 2. The system of claim 1, wherein said respiratory device further comprises a flow sensor that determines said flow rate of said gas flow. 29. The system of claim 28, wherein the flow sensor is positioned between a flow generator of the respiratory device and an outlet of the respiratory device. 30. A system according to claim 28 or 29, wherein the flow sensor is an ultrasonic type sensor system. The flow sensor comprises a first ultrasonic transducer for transmitting acoustic pulses through the gas flow and a second ultrasonic transducer for receiving the acoustic pulses, the gas flow based on the speed of sound between the transducers. 31. The system of claim 30, wherein the system determines the flow rate of The system of any one of claims 28-31, wherein the first parameter of the gas flow is based on the flow rate determined by the flow sensor.