Flow path sensing for flow therapy devices

Abstract

This application relates to flow path sensing for flow therapy devices. Systems and methods for respiratory therapy in a respiratory system can adjust the flow of respiratory gases based on a detected patient respiratory cycle. The respiratory system can include a non-sealing patient interface. The respiratory system can be configured to deliver high flow therapy. The patient respiratory cycle can be determined using one or more measured parameters such as flow rate, blower motor speed, and / or system pressure. A flow source can be adjusted to have a phase that matches the phase of the patient respiratory cycle such that the flow increases in response to patient inhalation and decreases in response to patient exhalation.

Description

[0001] This application is a divisional application of patent application 201780039600.0, filed on May 17, 2017, entitled "Flow path sensing for a flow therapy device". Technical Field

[0002] This disclosure relates to methods and systems for flow path sensing in flow therapy devices that deliver gas to a patient. This application claims priority to U.S. Patent Applications 62 / 337,795 and 62 / 507,013, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Respiratory assist devices are used in a variety of environments, such as hospitals, medical facilities, home care, or the home, to deliver a flow of gas to a user or patient. Respiratory assist devices or flow therapy devices may include valves for delivering oxygen and gas flow, and / or humidifiers for delivering heated and humidified gas. Flow therapy devices can allow adjustment and control of gas flow characteristics, including flow rate, temperature, gas concentration, humidity, pressure, etc. These gas characteristics are measured using sensors such as heated temperature sensing elements and / or thermistors. Summary of the Invention

[0004] This disclosure describes a flow therapy device that can be used to deliver a gas flow to a patient in a hermetic or hermetic system. The respiratory gas flow can be adjusted based on a detected patient respiratory cycle. The patient respiratory cycle can be determined using one or more measurement parameters such as flow rate, blower motor speed, and / or system pressure. A periodic waveform (adjusted to have a phase based on the phase of the patient's respiratory cycle) can be used to control the flow source, thereby adjusting the flow rate in response to the patient's inspiration and expiration.

[0005] A method for performing respiratory therapy in a respiratory system is provided. The method may include using a control signal to drive a blower motor configured to generate an airflow to a patient. The method may further include detecting the patient's respiratory cycle by: receiving a first sensor input including one or more flow measurements from at least one flow sensor; receiving a second sensor input including one or more pressure measurements from at least one pressure sensor or a motor speed measurement associated with the blower motor; and generating a respiratory cycle waveform using at least the received flow measurements, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient. The method may further include synchronizing the control signal with the respiratory cycle by: identifying the phase of the respiratory cycle waveform and repeatedly updating the phase of the control signal to achieve a determined phase difference between the control signal and the respiratory cycle waveform, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inspiratory and expiratory cycles. The method may further include phase-shifting the control signal based on a system delay between the blower motor receiving the control signal and one or more flow measurements. The method may further include phase-shifting the control signal such that the control signal preempts the respiratory cycle waveform by a set time amount. At least one flow sensor may include an ultrasonic sensor assembly. At least one flow sensor may further include a heated temperature sensing element. The control signal may be phase-locked to the respiratory cycle waveform. The amplitude of the control signal may be determined at least in part based on the amplitude of the respiratory cycle waveform, positive feedback parameters, and negative feedback parameters. The second input sensor may be one or more motor speed measurements associated with a blower motor. The received flow and motor speed measurements may be used to generate the respiratory cycle waveform. The respiratory cycle waveform may be generated at least in part based on a flow limit calculated using the received flow and motor speed measurements. The respiratory cycle waveform may be generated at least in part based on a calculated patient flow, wherein the patient flow may be based on a system leakage calculated using the received flow and motor speed measurements. The motor speed measurements may be determined at least in part based on one or more blower motor parameters. The blower motor may include a brushless DC motor. Detecting the patient's respiratory cycle may include receiving a third sensor input, which includes one or more pressure measurements from at least one pressure sensor. The second input sensor can be one or more pressure measurements from at least one pressure sensor. The method for performing respiratory therapy can be performed in a high-flow-rate breathing system. The method for performing respiratory therapy can be performed in an open-system breathing system. The method for performing respiratory therapy can be performed in a closed-system breathing system. The method may further include adjusting the motor speed based on one or more pressure measurements from at least one pressure sensor to achieve a predetermined pressure in the system.A sealed respiratory system may include a non-invasive ventilation mask. The pressure sensor may be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory system. The system may have memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0006] A respiratory therapy device is provided. The device may include a blower for generating airflow for a patient, the blower being associated with a motor, wherein the motor may be configured to be driven by a control signal. The device may further include one or more sensors configured to at least measure flow rate, the one or more sensors being further configured to measure motor speed or pressure. The device may further include a control system configured to detect a patient's respiratory cycle by: receiving a first sensor input including one or more flow measurements from at least one flow sensor; receiving a second sensor input including one or more pressure measurements from at least one pressure sensor or a motor speed measurement associated with the blower motor; and generating a respiratory cycle waveform using at least the received flow measurements, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient. The control system may be further configured to synchronize the control signal with the respiratory cycle by: identifying the phase of the respiratory cycle waveform; and repeatedly updating the phase of the control signal to achieve a determined phase difference between the control signal and the respiratory cycle waveform, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inspiratory and expiratory cycles. The control signal can be further configured to phase-shift based on the system delay between the blower motor receiving the control signal and the sensed airflow. The control signal can be further configured to phase-shift such that it preempts the respiratory cycle waveform setpoint by a certain amount of time. At least one flow sensor may include an ultrasonic sensor assembly. At least one flow sensor may further include a heated temperature sensing element. The control signal can be phase-locked to the respiratory cycle waveform. The respiratory cycle waveform can be used to calculate the patient's respiratory rate. The amplitude of the control signal can be determined at least in part based on the amplitude, positive feedback parameters, and negative feedback parameters of the respiratory cycle waveform. The second input sensor can be one or more motor speed measurements associated with the blower motor. The received flow rate and motor speed measurements can be used to generate the respiratory cycle waveform. The respiratory cycle waveform can be generated at least in part based on a calculated patient flow rate, wherein the patient flow rate can be based on a system leakage calculated using the received flow rate and motor speed measurements. The motor speed measurements can be determined at least in part based on one or more blower motor parameters. The blower motor may include a brushless DC motor. The control system can be configured to detect respiratory cycles by receiving a third sensor input, which includes one or more pressure measurements from at least one pressure sensor. A second input sensor can also be one or more pressure measurements from at least one pressure sensor. The respiratory therapy device can be a high-flow-rate respiratory therapy device. The respiratory therapy device can be configured for use in a non-sealed respiratory system. The respiratory therapy device can also be configured for use in a sealed respiratory system.The respiratory therapy device can be configured to adjust the motor speed based on one or more pressure measurements from a pressure sensor to achieve a predetermined pressure for a sealed breathing system. The respiratory therapy device can be configured to connect to a non-invasive ventilation mask. The pressure sensor can be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory therapy device. The device can have a memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0007] A method for adjusting the flow rate of a respiratory system based on a patient's inhalation and exhalation. The method includes: receiving a first input at a processor corresponding to the flow rate of an airflow generated by a source at least partially based on a control signal; receiving at least a second input at the processor; and the processor determining a predicted respiratory cycle of the patient based at least partially on the first and second inputs. The method may further include adjusting the control signal using positive feedback parameters at least partially based on the amplitude of the predicted respiratory cycle. The method may further include adjusting the control signal using negative feedback parameters at least partially based on the amplitude of the predicted respiratory cycle. The method may further include adjusting a control signal of the source, wherein adjusting the control signal includes performing at least one phase-locked loop iteration on the control signal relative to the predicted respiratory cycle, such that the phase of the control signal substantially matches the phase of the predicted respiratory cycle according to a determined phase difference. The second input may correspond to the speed of a motor associated with the source. The method may further include receiving a third input, the third input including pressure. The second input may correspond to pressure. Adjusting the control signal may further include phase-shifting the control signal relative to the predicted respiratory cycle. Adjusting the control signal may further include phase-shifting the control signal relative to the predicted respiratory cycle at least partially based on a system delay. Adjusting the control signal may further include phase-shifting the control signal relative to the predicted respiratory cycle to preemptively predict the respiratory cycle waveform by a specified amount. This method can be used in both open-closed and closed respiratory systems. The system may have memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0008] A system is provided configured to adjust a flow rate based on a patient's inspiration and expiration. The system may include a source configured to generate an airflow at least partially based on a control signal. The system may further include a processor configured to receive a first input corresponding to the flow rate of the airflow, receive at least a second input, and determine a predicted respiratory cycle of the patient at least partially based on the first and second inputs. The processor may be further configured to adjust the control signal using positive feedback parameters at least partially based on the amplitude of the predicted respiratory cycle. The processor may be further configured to adjust the control signal using negative feedback parameters at least partially based on the amplitude of the predicted respiratory cycle. The processor may be further configured to adjust the control signal of the source, wherein adjusting the control signal may include performing at least one phase-locked loop iteration on the control signal relative to the predicted respiratory cycle, such that the phase of the control signal can substantially match the phase of the predicted respiratory cycle according to a determined phase difference. Adjusting the control signal may further include phase shifting the control signal relative to the predicted respiratory cycle. The phase shifting of the control signal relative to the predicted respiratory cycle may be at least partially based on a system delay. The phase shifting of the control signal relative to the predicted respiratory cycle may be used to preemptively predict an amount specified in the respiratory cycle waveform. The processor may be further configured to calculate the patient's respiratory rate based at least in part on the patient's predicted respiratory cycles. A second input may correspond to the speed of a motor associated with a source. The processor may be further configured to receive a third input, which includes pressure. A second input sensor may correspond to pressure. The system may include a high-flow-rate system. The system may be an open-system breathing system. The system may be a closed-system breathing system. The respiratory therapy device is configured to adjust the motor speed to achieve a predetermined pressure for the system based on one or more pressure measurements from at least one pressure sensor. The system may include a non-invasive ventilation mask. The pressure sensor may be located in the non-invasive ventilation mask, or in a manifold connecting the non-invasive ventilation mask to the patient's breathing tube, or within the patient's breathing tube, or within the housing of the respiratory system. The system may have a memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0009] A method is provided for adjusting a control waveform of a respiratory assist device. The method may include: detecting a patient's respiratory cycle; synchronizing a control waveform with the detected respiratory cycle; and phase-shifting the control waveform relative to the detected respiratory cycle. The control waveform may be phase-shifted to have a determined phase difference relative to the respiratory cycle. Synchronizing the control waveform with the detected respiratory cycle may include using positive feedback to enhance the respiratory cycle. Synchronizing the control waveform with the detected respiratory cycle may include using negative feedback to regulate the respiratory cycle, wherein negative feedback may be applied to the respiratory cycle when the amplitude of the respiratory cycle meets a threshold amount. The control waveform may be a phase-locked loop relative to the detected respiratory cycle. The phase-locked loop may cause the error between the control waveform and the detected respiratory cycle to gradually decrease each cycle. The control waveform may be phase-shifted by an amount to compensate for system delays associated with the respiratory assist device. The control waveform may be phase-shifted by an amount to preempt the respiratory cycle. The respiratory assist device may include at least one flow sensor. The at least one flow sensor may include an ultrasonic sensor assembly. Flow feedback may be received from the at least one flow sensor. The respiratory assist device may include a blower. The blower may include a motor. Motor speed feedback may be received from the blower motor. The motor can be a brushless DC motor, configured to provide sensorless feedback. The motor can be a low-inertia motor. The method may further include using a phase-shifted control waveform to drive the blower motor. The respiratory assist device may include a blower comprising a motor and at least one flow sensor, and the method may further include receiving feedback variables from the motor and at least one flow sensor, wherein the received motor and flow sensor feedback variables may be calculated in combination to generate a respiratory cycle waveform. Motor speed feedback may be received from the blower motor. Feedback from the motor may include an indication of system pressure. The respiratory system may include a pressure sensor. The received pressure and flow sensor feedback variables may be calculated in combination to generate a respiratory cycle waveform. The received pressure, motor, and flow sensor feedback variables may be calculated in combination to generate a respiratory cycle waveform. The method for performing respiratory therapy may be performed in a high-flow respiratory system. The method for performing respiratory therapy may be performed in an open-system respiratory system. The method for performing respiratory therapy may be performed in a closed-system respiratory system. The method may further include adjusting the motor speed based on pressure measurements from a pressure sensor to achieve a predetermined system pressure. The closed-system respiratory system may include a non-invasive ventilation mask. The pressure sensor can be located in the non-invasive ventilation mask, in the manifold connecting the non-invasive ventilation mask to the patient's breathing tube, inside the patient's breathing tube, or within the housing of the respiratory system. The system may have memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0010] A respiratory assist device is provided, configured to adjust the flow rate based on a patient's inspiration and expiration. The device may include a blower comprising a motor. The device may further include at least one sensor for measuring the flow rate. The device may further include a processor configured to determine a predicted inspiratory and expiratory cycle for the patient based at least on the flow rate and to adjust the flow rate of respiratory gases based on the patient's breathing. The at least one sensor may include a first ultrasonic transducer and a second ultrasonic transducer. The at least one sensor may include a heated temperature sensing element. The at least one sensor may include both the first and second ultrasonic transducers and the heated temperature sensing element. The flow rate of the respiratory gases may be adjusted at least in part based on a bistable system using both positive and negative feedback. The processor may determine the predicted inspiratory and expiratory cycle based on the flow rate and a signal indicating the speed of the blower motor, the motor being configured to provide the signal indicating the speed of the blower motor. The respiratory assist device may further include a pressure sensor for measuring pressure. The processor may determine the predicted inspiratory and expiratory cycle based on the flow rate and pressure. The processor may determine the predicted inspiratory and expiratory cycle based on the flow rate, motor speed, and pressure. The respiratory assist device can be a high-flow respiratory assist device. The respiratory therapy device can be configured for use in a non-sealed respiratory system. The respiratory therapy device can be configured for use in a sealed respiratory system. The respiratory therapy device can be configured to adjust the motor speed based on pressure measured by a pressure sensor to achieve a predetermined pressure for a sealed respiratory system. The respiratory therapy device can be configured to connect to a non-invasive ventilation mask. The pressure sensor can be located in the non-invasive ventilation mask, or in a manifold connecting the non-invasive ventilation mask to the patient's breathing tube, or within the patient's breathing tube, or within the housing of the respiratory assist device. The device can have a memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0011] A system is provided configured to adjust the flow rate based on a patient's inspiratory and expiratory breaths. The system may include a blower and a processor. The processor may be configured to receive a first input corresponding to the flow rate, and a second input. The processor may be further configured to determine a patient's predicted inspiratory and expiratory cycles based on the first and second inputs, and to adjust the flow rate of the respiratory gas according to the patient's predicted inspiratory and expiratory cycles. A first ultrasonic transducer and a second ultrasonic transducer may be used to determine the flow rate. A heated temperature sensing element may be used to determine the flow rate. A combination of a first ultrasonic transducer and a second ultrasonic transducer and a heated temperature sensing element may be used to determine the flow rate. The flow rate of the respiratory gas may be adjusted at least in part based on a bistable system using both positive and negative feedback. The second input may be a motor speed feedback device configured to provide a signal indicating the speed of the blower motor. The processor may be further configured to receive a third input, which includes pressure. The second input may be pressure from a pressure sensor. The system may be a high-flow-rate system. The respiratory therapy device may be configured for use in a non-sealed respiratory system. The respiratory therapy device may be configured for use in a sealed respiratory system. The respiratory therapy device can be configured to adjust the motor speed based on pressure from a pressure sensor to achieve a predetermined pressure for a sealed breathing system. The respiratory therapy device can be configured to connect to a non-invasive ventilation mask. The pressure sensor can be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory therapy device. In addition to motor feedback, a second input can also be pressure. The system can have a memory for storing data. The stored data can include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory can be an EEPROM.

[0012] A respiratory system configured to determine a patient's respiratory rate is provided. The system may further include: at least one sensor configured to measure flow rate; and a processor configured to be electrically connected to the at least one sensor to receive flow rate measurements of the patient using the respiratory system, the processor being further configured to determine the patient's respiratory rate by autocorrelation of a graph of the flow rate measurements versus time. The processor may be configured to determine a respiratory cycle from one or more peaks or zero-crossings of the autocorrelation of the graph of the flow rate measurements versus time. The at least one sensor may include a first ultrasonic transducer and a second ultrasonic transducer. The at least one sensor may include a heated temperature sensing element. The at least one sensor may include both the first and second ultrasonic transducers and the heated temperature sensing element. The processor may be configured to generate a respiratory cycle waveform based at least in part on the determined respiratory rate, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient. The system may further include a blower for generating airflow for the patient, the blower being associated with a motor, wherein the motor is configurable to be driven by a control signal. The blower motor may include a brushless DC motor. The processor can be configured to synchronize the control signal with the respiratory cycle by: identifying the phase of the respiratory cycle waveform; and repeatedly updating the phase of the control signal to achieve a determined phase difference between the control signal and the respiratory cycle waveform, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inspiration and expiration. The processor can be further configured to phase-shift the control signal based on the system delay between the blower motor receiving the control signal and the sensed airflow. The processor can be further configured to phase-shift the control signal such that the control signal preempts the respiratory cycle waveform by a set time amount. The processor can be configured to generate the respiratory cycle waveform based on flow rate measurements and motor speed measurements associated with the blower motor. The motor speed measurement can be determined at least in part based on one or more blower motor parameters. The generation of the respiratory cycle waveform can be based on the flow rate measurement and one or more pressure measurements from a pressure sensor. The generation of the respiratory cycle waveform can be based on the flow rate measurement, the motor speed measurement, and one or more pressure measurements from a pressure sensor. The respiratory system can include a high-flow-rate respiratory therapy device. The respiratory system can be an open-system respiratory system. The respiratory system can be a closed-system respiratory system. The processor can be configured to adjust the motor speed based on one or more pressure measurements from a pressure sensor to achieve a predetermined pressure for the system. The respiratory system may include a non-invasive ventilation mask. The pressure sensor may be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory system. The system may have memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure.The memory can be EEPROM.

[0013] A method is provided for determining a patient's respiratory rate using a respiratory system. The method may include: receiving a flow rate measurement of the patient obtained using the respiratory system from at least one sensor; autocorreling a graph of the flow rate measurement against time; and determining the patient's respiratory rate from the autocorrelation. Determining the patient's respiratory rate may further include determining the patient's respiratory cycle from one or more peaks or zero-crossings in the autocorrelation. Flow rate measurement may be performed by a first ultrasonic transducer and a second ultrasonic transducer. Flow rate measurement may be performed by a heated temperature sensing element. Flow rate measurement may be performed by both the first and second ultrasonic transducers and the heated temperature sensing element. The method may further include generating a respiratory cycle waveform based at least in part on the determined respiratory rate, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient. The respiratory system may include a blower for generating airflow for the patient, the blower being associated with a motor, wherein the motor is configurable to be driven by a control signal. The blower motor includes a brushless DC motor. The method may further include synchronizing the control signal with the respiratory cycle by identifying the phase of the respiratory cycle waveform and repeatedly updating the phase of the control signal to achieve a determined phase difference between the control signal and the respiratory cycle waveform, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inhalation and exhalation. Synchronization may further include phase shifting the control signal based on a system delay between the blower motor receiving the control signal and the patient sensing the airflow. Synchronization may further include phase shifting the control signal such that the control signal preempts the respiratory cycle waveform by a set time amount. The method may further include generating the respiratory cycle waveform based on a determined respiratory rate and a motor speed measurement associated with the blower motor. The method may further include determining the motor speed measurement based on one or more blower motor parameters. Generating the respiratory cycle waveform may be based on the determined respiratory rate and one or more pressure measurements from a pressure sensor. Generating the respiratory cycle waveform may be based on the determined respiratory rate, one or more blower motor parameters, and one or more pressure measurements from a pressure sensor. The respiratory system may include a high-flow-rate respiratory therapy device. The respiratory system may be an open-system respiratory system. The respiratory system can be a sealed respiratory system. The processor can be configured to adjust the motor speed based on pressure measurements from a pressure sensor to achieve a predetermined pressure for the system. The respiratory system may include a non-invasive ventilation mask. The pressure sensor may be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory system. The system may have memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0014] A respiratory therapy device is provided. This respiratory therapy device may include: a blower for generating airflow for a patient, the blower being associated with a motor, wherein the motor is configurable to be driven by a control signal; one or more sensors configured to at least measure flow rate; and a control system configured to detect the patient's respiratory cycle by: receiving one or more flow measurements from the one or more sensors; generating a respiratory cycle waveform using at least the received flow, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient; and identifying a phase difference between the control signal and the respiratory cycle waveform from a cross-correlation of the control signal and the respiratory cycle waveform. The control system may be configured to determine / measure the phase difference from one or more peaks or zero-crossings of the cross-correlation of the control signal and the respiratory cycle waveform. The control system may be configured to synchronize the control signal with the respiratory cycle by: repeatedly updating the phase of the control signal to achieve the determined phase difference between the control signal and the respiratory cycle waveform based on the identified phase difference, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inspiratory and expiratory cycles. The control signal can be further configured to phase-shift based on the system delay between the control signal received by the blower motor and the airflow sensed by the patient. The control system can be further configured to phase-shift the control signal such that the control signal preempts the respiratory cycle waveform by a set time amount. One or more sensors may include an ultrasonic sensor assembly. One or more sensors may further include a heated temperature sensing element. The control signal can be phase-locked to the respiratory cycle waveform. The respiratory cycle waveform can be used to calculate the patient's respiratory rate. The patient's respiratory rate can be calculated from the autocorrelation of the flow rate measurement over time. The patient's respiratory cycle can be determined from one or more peaks or zero crossings in the autocorrelation. The amplitude of the control signal can be determined at least in part based on the amplitude, positive feedback parameters, and negative feedback parameters of the respiratory cycle waveform. The respiratory cycle waveform can be generated based on the received flow rate and the motor speed measurement associated with the blower motor. The respiratory cycle waveform can be generated at least in part based on the calculated patient flow rate, wherein the patient flow rate is based on a system leakage calculated using the received flow rate and the motor speed measurement associated with the blower motor. The motor speed measurement can be determined at least in part based on one or more blower motor parameters. The blower motor may include a brushless DC motor. The control system may be configured to generate a respiratory cycle waveform based on the received flow rate and one or more pressure measurements from a pressure sensor. The control system may also be configured to generate a respiratory cycle waveform based on the received flow rate, a motor speed measurement associated with the blower motor, and one or more pressure measurements from a pressure sensor. The respiratory therapy device may be a high-flow-rate respiratory therapy device. The respiratory therapy device may be configured for use in a non-sealed respiratory system. The respiratory therapy device may also be configured for use in a sealed respiratory system.The respiratory therapy device can be configured to adjust the motor speed based on pressure measurements from a pressure sensor to achieve a predetermined pressure for the sealed breathing system. The respiratory therapy device can be configured to connect to a non-invasive ventilation mask. The pressure sensor can be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory therapy device. The system can have a memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM.

[0015] A method for performing respiratory therapy in a respiratory system is disclosed. The method may include: using a control signal to drive a blower motor configured to generate an airflow to a patient; detecting the patient's respiratory cycle by receiving one or more flow measurements from at least one flow sensor; generating a respiratory cycle waveform using the received flow, wherein the respiratory cycle waveform may include multiple alternating inspiratory and expiratory cycles of the patient; and identifying a phase difference between the control signal and the respiratory cycle waveform from a cross-correlation of the control signal and the respiratory cycle waveform. Identification may further include determining the phase difference from one or more peaks or zero-crossings of the cross-correlation of the control signal and the respiratory cycle waveform. The method may further include synchronizing the control signal with the respiratory cycle by repeatedly updating the phase of the control signal to achieve the determined phase difference between the control signal and the respiratory cycle waveform based on the identified phase difference, such that the control signal can be configured to adjust the speed of the blower motor based on the patient's inhalation and exhalation. Synchronization may further include phase shifting the control signal based on a system delay between the blower motor receiving the control signal and the airflow sensed by the patient. Synchronization may further include phase-shifting the control signal so that the control signal preemptively sets the respiratory cycle waveform by a set time amount. At least one flow sensor may include an ultrasonic sensor assembly. At least one flow sensor may include a heated temperature sensing element. The method may further include phase-locking the control signal to the respiratory cycle waveform. The respiratory cycle waveform can be used to calculate the patient's respiratory rate. Detection may further include calculating the patient's respiratory rate from the autocorrelation of the flow rate measurement over time. The patient's respiratory cycle can be determined from one or more peaks or zero crossings in the autocorrelation. The amplitude of the control signal can be determined at least in part based on the amplitude of the respiratory cycle waveform, positive feedback parameters, and negative feedback parameters. The respiratory cycle waveform can be generated based on one or more received flow measurements and a motor speed measurement associated with the blower motor. The respiratory cycle waveform can be generated at least in part based on a flow limit calculated using the received flow and the motor speed measurement associated with the blower motor. The respiratory cycle waveform can be generated at least in part based on a calculated patient flow, wherein the patient flow can be based on a system leakage calculated using the received flow and motor speed measurements. Motor speed measurements can be determined at least in part based on one or more blower motor parameters. The blower motor may include a brushless DC motor. A respiratory cycle waveform can be generated based on the received flow rate and one or more pressure measurements from a pressure sensor. A respiratory cycle waveform can also be generated based on one or more flow rate measurements, a motor speed measurement associated with the blower motor, and one or more pressure measurements from a pressure sensor. This method can be performed in a high-flow-rate breathing system. This method can be performed in a non-sealed breathing system. Methods for performing respiratory therapy can be performed in a sealed breathing system.The method may further include adjusting the motor speed based on pressure measurements from a pressure sensor to achieve a predetermined system pressure. The sealed respiratory system may include a non-invasive ventilation mask. The pressure sensor may be located within the non-invasive ventilation mask, in a manifold connecting the non-invasive ventilation mask to a patient's breathing tube, within the patient's breathing tube, or within the housing of the respiratory system. The system may have a memory for storing data. The stored data may include respiratory rate, treatment time, motor speed, flow rate, and / or pressure. The memory may be an EEPROM. Attached Figure Description

[0016] Figure 1 An example respiratory assist device in the form of a flow therapy device is illustrated.

[0017] Figure 2A An example block diagram of a control system that interacts with and / or provides control and guidance to components of a respiratory support system is shown.

[0018] Figure 2B An example block diagram of a control system that interacts with and / or provides control and guidance to components of a respiratory support system is shown.

[0019] Figure 2C A block diagram of a sample controller is shown.

[0020] Figure 3 A block diagram of an example motor / sensor module is shown.

[0021] Figure 4 A flowchart illustrating an example process for adjusting the operation of a flow therapy device is shown.

[0022] Figure 5 A flowchart illustrating an example process for determining the flow rate is shown.

[0023] Figure 6A A block diagram of an example system for performing respiratory and circulatory enhancement for a flow therapy device is shown.

[0024] Figure 6B A block diagram of an example system for implementing a phase-locked control loop for a flow therapy device is shown.

[0025] Figure 7 A flowchart illustrating an example procedure for assisting a patient's respiratory cycle is provided.

[0026] Figure 8 Example charts showing the patient's respiratory and circulatory waveforms and control signal waveforms are provided.

[0027] Figure 9A flowchart illustrates an example process for implementing control signals from a blower motor into a phase-locked loop with sensed patient respiratory cycles.

[0028] Figure 10 A flowchart illustrating an example process for phase-shifting control signals to compensate for system delays is shown.

[0029] Figure 11 A graph is shown illustrating how updated control signals are used to compensate for system latency.

[0030] Figure 12 A flowchart illustrating an example process for configuring control signals for phase shifting to preempt the patient's respiratory cycle waveform is shown.

[0031] Figure 13 An example diagram showing the control loops for the patient's respiratory cycle and phase shift is provided.

[0032] Figure 14A Example graphs show the raw flow rate readings of the patient as measured by the system.

[0033] Figure 14B Showing Figure 14A Example graph of the autocorrelation of the raw flow rate readings. Detailed Implementation

[0034] Figure 1 The image shows a flow therapy device 10. Generally, device 10 may include a main housing 100 containing a flow generator 11 arranged as a motor / impeller, an optional humidifier 12, a controller 13, and a user interface 14 (e.g., including a display and input devices such as buttons, a touchscreen, etc.). The controller 13 is configured or programmed to control components of the device, including: operating the flow generator 11 to generate a gas flow for delivery to a patient; operating the humidifier 12 (if present) to humidify and / or heat the generated gas flow; receiving user input from the user interface 14 for reconfiguration and / or user-defined operations of the device 10; and outputting information (e.g., on a display) to the user. The user can be a patient, a healthcare professional, or any other person interested in using the device.

[0035] The patient breathing tube 16 is connected to the gas flow output 21 in the housing 100 of the flow therapy device 10 and to the patient interface 17 (such as a nasal cannula with a manifold 19 and a nasal plug 18). Alternatively or additionally, the patient breathing tube 16 may be connected to a face mask. A gas flow (which may be humidified) is generated by the flow therapy device 10 and delivered to the patient via the patient tube 16 through the cannula 17. The patient tube 16 may have a heater line 16a for heating the gas flow to the patient. The heater line 16a is under the control of the controller 13. The patient tube 16 and / or the patient interface 17 may be considered part of the flow therapy device 10, or alternatively, on its periphery. The flow therapy device 10, the breathing tube 16, and the patient interface 17 together form a flow therapy system.

[0036] The general operation of the flow-based therapeutic respiratory device 10 will now be described. The controller 13 can control the flow generator 11 to generate a gas flow at a desired flow rate, control one or more valves to control the gas mixture (e.g., O2 control), and / or control the humidifier 12 (if present) to humidify and / or heat the gas flow to an appropriate level. The gas flow is directed to the patient through the patient catheter 16 and cannula 17. The controller 13 can also control the heating element in the humidifier 12 and / or the heating element 16a in the patient catheter 16 to heat the gas to a desired temperature for therapeutic and / or patient comfort levels. The controller 13 can be programmed to have or determine a suitable target temperature for the gas flow.

[0037] Operating sensors 3a, 3b, 3c (such as flow sensors, temperature sensors, humidity sensors, and / or pressure sensors) can be placed at various locations within the flow therapy device 10. Additional sensors (e.g., sensors 20, 25) can be placed at different locations on the patient catheter 16 and / or cannula 17 (e.g., a temperature sensor may be present at or near the end of the inspiratory tube). Outputs from the sensors can be received by a controller 13 to assist the controller in operating the flow therapy device 10 in a manner that provides appropriate treatment. Providing appropriate treatment may include meeting the patient's inspiratory needs. The device 10 may have transmitters and / or receivers 15 to enable the controller 13 to receive signals 8 from the sensors and / or control various components of the flow therapy device 10, including but not limited to the flow generator 11, humidifier 12, and heater line 16a, or accessories or peripheral devices associated with the flow therapy device 10. The device 10 may have memory for storing data such as respiratory rate, treatment time, motor speed, flow rate, pressure, etc. The memory may be, for example, an EEPROM. Alternatively or concurrently, transmitter and / or receiver 15 may deliver data to a remote server or enable remote control of device 10.

[0038] Flow therapy device 10 may include a high-flow-rate therapy device. As used herein, “high-flow-rate” therapy may involve administering gas to a patient’s airway at a relatively high flow rate, for example, for adults, at least 15 L / min, or 20 L / min, or 25 L / min, or 30 L / min, or 40 L / min, or 50 L / min, or up to 150 L / min. For children and infants, the flow rate may be 1 L / min and up to 25 L / min, or 2 L / min, or 3 L / min, or 5 L / min, or 10 L / min, or 15 L / min, or 20 L / min. High-flow-rate therapy may be administered through the user’s nostrils and / or orally, or via a tracheostomy interface. High-flow-rate therapy delivers gas to the user at a flow rate equal to or exceeding the user’s expected peak inspiratory flow rate requirement. High-flow-rate gas reaching the patient’s airway can facilitate airway flushing, which can reduce the volume of anatomical dead space. High-flow-rate therapy is typically delivered via a non-sealed patient interface (e.g., a nasal cannula). The nasal cannula can be configured to deliver breathing gas into the user's nostrils at a rate exceeding the user's expected peak inspiratory flow rate requirement.

[0039] As used herein, the term "unsealed patient interface" can refer to an interface that provides a pneumatic connection between a patient's airway and a positive gas flow source (such as from flow generator 11) without completely obstructing the patient's airway. An unsealed pneumatic connection may include less than 95% obstruction of the patient's airway. An unsealed pneumatic connection may include less than 90% obstruction of the patient's airway. An unsealed pneumatic connection may include obstruction between 40% and 80% of the patient's airway. The airway can be one or more of the patient's nostrils or mouth.

[0040] The system described herein can also be used with a sealed patient interface. Non-limiting examples of sealed patient interfaces may include non-invasive ventilation (NIV) full-face masks and nasal masks. NIV masks can support a patient's breathing without intubation or tracheostomy. NIV masks may have a patient interface that conforms to the patient's face to provide a sealed fit between the mask and the patient's face.

[0041] Additional details of an example flow therapy device are disclosed in U.S. Provisional Application Serial No. 62 / 262,325 entitled “Flow Path Sensing for Flow Therapy Apparatus”, filed on December 2, 2015, the full text of which is incorporated herein by reference.

[0042] control system

[0043] Figure 2AA block diagram 200 illustrates an example control system 220 that can detect patient condition and control the operation of a flow therapy device including a gas source. The control system 220 can manage the flow rate of gas flowing through the flow therapy device as it is delivered to the patient. For example, the control system 220 can increase or decrease the flow rate by controlling the output 230 of the blower motor speed (hereinafter also referred to as the "blower motor") or the output 232 of a valve in a mixer. As described below, the control system 220 can automatically determine a setpoint or personalized flow rate value for a specific patient. The flow rate can be optimized by the control system 220 to improve patient comfort and treatment.

[0044] The control system 220 may also generate audio and / or display / visual outputs 238, 239. For example, the flow therapy device may include a display 308 and / or a speaker. The display 308 may indicate any warnings or alarms generated by the control system 220 to the physician. The display 308 may also indicate control parameters that can be adjusted by the physician. For example, the control system 220 may automatically recommend a flow rate for a specific patient. The control system 220 may also determine the patient's respiratory status, including but not limited to generating the patient's respiratory rate and sending it to the display.

[0045] The control system 220 can change the heater control output to control one or more of the heating elements (e.g., to maintain a temperature setpoint for the gas delivered to the patient). The control system 220 can also change the operation or duty cycle of the heating elements. The heater control output may include a heating plate control output 234 and a heated breathing tube control output 236.

[0046] The control system 220 can determine the outputs 230-239 based on one or more received inputs 201-216. Inputs 201-216 may correspond to sensor measurements automatically received by the controller 300 (such as...). Figure 2B (As shown). The control system 220 can receive sensor inputs, including but not limited to temperature sensor input 201, flow rate sensor input 202, motor speed input 203, sensor input 204, gas fraction sensor input 205, humidity sensor input 206, pulse oximeter (e.g., SpO2) sensor input 207, stored parameters or user parameters 208, duty cycle or pulse width modulation (PWM) input 209, voltage input 210, current input 211, acoustic sensor input 212, power input 213, resistance input 214, CO2 sensor input 215, and / or spirometer input 216. The control system 220 can receive inputs from user parameter values ​​or stored parameter values ​​in memory 304 (e.g., ...). Figure 2B(As shown). The control system 220 can dynamically adjust the patient's flow rate during treatment. The control system 220 can continuously monitor system parameters and patient parameters. Based on the disclosure herein, those skilled in the art will understand that any other suitable inputs and / or outputs can be used with the control system 220.

[0047] like Figure 2B As shown, the control system 220 can receive inputs from multiple components of the flow therapy device, such as chest-abdominal dysregulation (TAA) sensor input 202, respiratory sensor input 204, work of breathing (WOB) sensor input 206, CO2 and / or pressure sensor input 208, user input and / or stored values ​​210. Not necessarily. Figure 2A All inputs 202-210 shown may exist. Figure 2B The control system 220 can output heater control output 230, flow control output 232, and display / audio output 234 based on inputs 202-210. Inputs 202-210 and outputs 230-234 may not be necessary. For example, the control system 220 may only receive EMG input 206 and generate flow control measurement value 232. Depending on the configuration, some components corresponding to the inputs may not be included in the flow therapy device. The control system 220 can use the absence of the input itself to determine input conditions or system conditions.

[0048] controller

[0049] The control system 220 may include programming instructions for detecting input conditions and controlling output conditions. These programming instructions may be stored in the memory 304 of the controller 300, such as... Figure 2B As shown. Programming instructions may correspond to the methods, processes, and functions described herein. Control system 220 may be executed by one or more hardware processors 302 of controller 300. Programming instructions may be implemented in C, C++, JAVA, or any other suitable programming language. Some or all parts of control system 220 may be implemented in dedicated circuitry 306 such as ASICs and FPGAs.

[0050] Figure 2C A block diagram of an example controller 300 is shown. The controller may include a hardware processor 302 capable of executing instructions stored in memory 304. The control system 220 may be stored as programming instructions in memory 304. The controller may also include circuitry 306 for receiving sensor signals. The controller may further include a display 308 for transmitting the status of the patient and the respiratory support system. The display 308 may also display warnings. The controller may also receive user input via a user interface such as the display 308. The user interface may alternatively or additionally include buttons or a dial.

[0051] Motor / Sensor Module

[0052] Figure 3 A block diagram of a motor / sensor module 2000, which can be used as part of a flow therapy device, is shown. The motor / sensor module includes a blower 2001 that entrains indoor air for delivery to the patient. The blower 2001 can be a centrifugal blower.

[0053] Indoor air enters through indoor air inlet 2002, which then enters blower 2001 through inlet port 2003. Inlet port 2003 may include valve 2004, through which pressurized gas enters blower 2001. Valve 2004 controls the flow of oxygen into blower 2001. Valve 2004 can be any type of valve, including proportional valves or dual-state valves. Inlet port may not include a valve.

[0054] Blower 2001 can 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 20,000 RPM and less than 24,000 RPM, or any of the foregoing values. Operation of blower 2001 will result in the mixing of the gas entering blower 2001 through inlet port 2003. Using blower 2001 as a mixer can reduce pressure drops that would otherwise occur in systems with separate mixers (such as static mixers including baffles), since mixing requires energy and the blower provides that energy.

[0055] The mixed air exits the blower 2001 through duct 2005 and enters the flow path 2006 in the measuring chamber 2007. A circuit board with a sensor 2008 is positioned in the measuring chamber 2007 such that the circuit board is immersed in the gas flow. The sensor 2008 on the circuit board is positioned within the gas flow to measure the gas characteristics within the flow. After passing through the flow path 2006 in the measuring chamber 2007, the gas exits 2009 and enters the liquid chamber 300.

[0056] Positioning sensor 2008 downstream of the combined blower and mixer 2001 improves the accuracy of measurements (such as measurements of gas fractional concentration, including oxygen concentration) compared to systems that position the sensor upstream of the blower and / or mixer. Such positioning provides repeatable flow profiles. Furthermore, positioning the sensor downstream of the combined blower and mixer avoids pressure drops that would otherwise occur, as a separate mixer, such as a static mixer with baffles, is required between the inlet and the sensing system in cases where sensing occurs before the blower. The mixer introduces a pressure drop. Positioning the sensor after the blower allows the blower to act as the mixer, whereas a static mixer would reduce pressure, whereas the blower would increase pressure. Additionally, immersing the circuit board and sensor 2008 in the flow path improves measurement accuracy, as the sensors being submerged in the flow means they are more likely to be at the same temperature as the gas flow and therefore better represent the gas characteristics.

[0057] Measurement Room

[0058] like Figure 3 As shown, the measuring chamber 2007 can be positioned downstream of the blower 2001 within the motor / sensor module 2000. The measuring chamber 2007 includes a flow path 2006 and is designed to hold a circuit board and one or more sensors 2008.

[0059] Gas flow may experience pressure drops during its passage through a flow therapy device, which consumes energy and can consequently affect the system's ability to achieve a specific flow rate. Pressure losses may be due to friction in the straight sections of the flow path or due to deviations from the straight path (such as bends, valves, contractions, or expansions in the path).

[0060] Flow path 2006 has a curved shape. The gas flow enters at inlet 2103, flows along the curved flow path 2104, and exits on the opposite side of flow path 2105. The inlet and outlet can be positioned in vertically opposite directions, and the gas flow can enter the path vertically upwards, then curve horizontally, and then curve vertically upwards again. The flow path may not have sharp turns. The flow path can have curved ends and a relatively straight middle section. The flow path can maintain a constant cross-sectional shape throughout its entire length. The flow path can taper slightly inwards from a first end and widen again to a second end, which can accelerate the flow for better accuracy, stability, and reproducibility in measurements. The surface of the flow path can be lined with a surface modifier / lubricant to reduce friction within the flow path. The curved flow path shape can reduce the pressure drop of the gas flow without reducing the sensitivity of the flow measurement by aligning the measurement area with a portion of the flow path. Many different flow path configurations can be used. Other examples of possible flow path configurations are disclosed in U.S. Provisional Application Serial No. 62 / 262,325 cited in this article.

[0061] Adjusting flow rate based on respiratory circulation

[0062] To better assist a patient's breathing, it may be beneficial to be able to adjust the operation of the flow therapy device based on the patient's respiratory cycle. For example, the flow rate of air supplied by the flow therapy device can be adjusted with the patient's inhalation and exhalation. The flow rate can be adjusted based on the patient's inhalation or exhalation. For example, the flow rate can be increased during the patient's inhalation and decreased during the patient's exhalation. The flow rate can be adjusted during the patient's inhalation (e.g., increased during inhalation) and not adjusted during the patient's exhalation, and vice versa. Inhalation and exhalation can also be referred to as inhalation and exhalation.

[0063] A patient's respiratory cycle can be represented as a waveform comprising alternating expiratory and inspiratory phases. By identifying and monitoring the patient's respiratory cycle waveform, the operation of a flow therapy device can be modified based on the patient's respiratory cycle. For example, the flow therapy device can be configured to use a periodic waveform to control gas flow, which can be adjusted based on the patient's measured respiratory cycle waveform.

[0064] Figure 4 A flowchart illustrating an example process for adjusting the operation of a flow therapy device is provided. At box 402, a control signal is used to drive the blower motor associated with the flow therapy device (e.g., as shown in the diagram). Figure 1 The flow generator 11 shown or Figure 3(The blower shown is 2001). A blower motor can be used to generate an airflow to assist the patient's breathing. Control signals may include an initial waveform. The initial waveform may include a default waveform, or it may be based on one or more measurements associated with the patient.

[0065] At box 404, multiple measurements that can be used to determine the patient's respiratory cycle are received. These measurements may include flow rate 404a, motor speed 404b, pressure 404c, etc. Each of these types of measurements will be described in more detail below.

[0066] At box 406, the received measurements are used to determine the patient's predicted respiratory cycle. One or more different techniques (such as flow deviation 406a, flow limitation 406b, system leakage 406c, etc.) can be used to determine the patient's predicted respiratory cycle. Each of these different techniques will be described in more detail below.

[0067] At block 408, the control signal to the blower motor is adjusted based on a predicted respiratory cycle. For example, the control signal can be adjusted so that the flow rate increases during patient inspiration and decreases during patient expiration. The control signal can be configured with a phase-locked loop that predicts the respiratory cycle. Each of these embodiments will be described in more detail below.

[0068] The process can then return to box 402, where the adjusted control signal is used to drive the blower motor to generate an airflow for the patient.

[0069] Measurement system parameters

[0070] As discussed, a patient’s respiratory circulation can be determined at least in part based on several different measurements, such as measured flow rate, measured motor speed, measured pressure, or a combination thereof.

[0071] a) flow

[0072] Flow refers to the flow of gas through a system (e.g., from a blower motor or other flow generator to a patient). One or more flow sensors can be used to measure the flow rate. For example, a heated temperature sensing element can be used to measure the flow rate. A heated temperature sensing element may include a heated temperature sensing element, a hot-wire anemometer, such as a platinum wire or heated thermistor, and / or a negative temperature coefficient (NTC) thermistor. Other non-limiting examples of heated temperature sensing elements include glass or epoxy-encapsulated or unencapsulated thermistors. The heated temperature sensing element is configured to measure the flow rate of the gas.

[0073] Flow rate can be measured using fast-response-time flow sensors, such as ultrasonic sensor assemblies comprising a first ultrasonic transducer and a second ultrasonic transducer. One or more sensors can be located along the flow path (such as...). Figure 3 The flow path shown is located near the flow path. U.S. Provisional Application Serial No. 62 / 262,325, cited herein, discloses an example of using an ultrasonic transducer to measure flow rate along a portion of a flow path. Specifically, a first ultrasonic transducer may be located downstream of the flow path in the aforementioned measurement chamber, and a second ultrasonic transducer may be located upstream of the flow path in the aforementioned measurement chamber. The first and second ultrasonic transducers may each emit and receive ultrasonic signals from each other. A controller of the breathing device may determine one or more characteristics of the gas flow, including but not limited to flow rate, based on time-of-flight measurements between the first and second ultrasonic transducers. Flow rate may also be measured using one or more ultrasonic transmitters and one or more ultrasonic receivers (such as microphones). One or more ultrasonic transmitters may emit ultrasonic signals along an acoustic path. One or more ultrasonic receivers may be located and receive ultrasonic signals along an acoustic path. A controller of the breathing device may determine one or more characteristics of the gas flow, including but not limited to flow rate, based on time-of-flight measurements between one or more ultrasonic transmitters and ultrasonic receivers.

[0074] Because the system's flow rate can fluctuate with a patient's inspiration and expiration, it is important to be able to measure the flow rate quickly and accurately. A combination of two or more different sensors can be used to measure the flow rate. For example, a first-type sensor may be able to measure the flow rate with better short-term or local accuracy (e.g., detecting rapid respiratory changes in flow rate) but may have poorer long-term accuracy (e.g., due to the accumulation of small errors), while a second-type sensor may be able to measure the flow rate with poorer local accuracy (e.g., due to local noise) but better average accuracy. The output readings from both the first-type and second-type sensors can be combined to determine a more accurate flow measurement. For example, a previously determined flow rate and one or more outputs from the second-type sensor can be used to determine a predicted current flow rate. The predicted current flow rate can then be updated using one or more outputs from the first-type sensor to calculate the final flow rate. The first-type sensor may include an ultrasonic sensor assembly, while the second-type sensor may include a heated temperature sensing element.

[0075] Figure 5A flowchart illustrating an example process for determining flow rate is shown. At box 502, a first flow rate measurement is received from a first flow sensor (such as a heated temperature sensing element sensor). At box 504, a second flow rate measurement is received from an ultrasonic sensor assembly as described above.

[0076] At box 506, the current flow rate prediction is determined based on the second flow rate measurement and the previous flow rate measurement. At box 508, the flow rate is determined using the current flow rate prediction and the first flow rate measurement. By utilizing both a heated temperature sensing element sensor and an ultrasonic transducer, the drawbacks of both types of sensors can be mitigated, allowing for rapid and accurate flow rate measurement.

[0077] Measurements from different types of sensors can be combined in various ways. For example, measurements from one or more ultrasonic transducers can be read directly while measurements from a heated temperature sensing element are filtered to provide a basis for correction of ultrasonic flow calculations (e.g., by using a heated temperature sensing element (which has better long-term accuracy) to correct measurements from an ultrasonic transducer (which exhibits a faster response time)).

[0078] b) Motor speed

[0079] One or more sensors (e.g., Hall effect sensors) can be used to measure the motor speed of the blower motor. The blower motor may include a brushless DC motor from which the motor speed can be measured without the use of a separate sensor. For example, during operation of the brushless DC motor, the back electromotive force can be measured from the motor's non-energized windings, the motor position can be determined from these windings, and the motor speed can then be calculated using these positions. Furthermore, a motor driver can be used to measure the motor current, which can be used in conjunction with the measured motor speed to calculate the motor torque. The blower motor may include a low-inertia motor.

[0080] c) pressure

[0081] System pressure can be determined using one or more pressure sensors. These pressure sensors can be gauge pressure sensors or absolute pressure sensors. The pressure sensors can be located anywhere in the system, but at least one pressure sensor can be positioned within the flow path of the main housing of the breathing device. System pressure can also be determined using one or more motor parameters without requiring a separate pressure sensor. Pressure sensors can be used to confirm the system pressure determined by the motor parameters.

[0082] Using motor parameters to calculate system pressure can provide good short-term accuracy, but may have poor long-term average accuracy compared to using a single pressure sensor. Therefore, the output from the pressure sensor and the motor parameters can be used together to determine an accurate system pressure measurement (e.g., using one or more techniques described above regarding flow rate measurement).

[0083] Determine respiratory and circulatory systems

[0084] a) Flow deviation

[0085] The system's flow rate Q can be observed relative to the average or setpoint flow rate value. The deviation is used to determine the patient's respiratory cycle. For example, the flow rate may tend to increase in response to the patient's inspiration and decrease in response to the patient's expiration. However, since the motor speed may also vary, it may be difficult to determine which part of the deviation is due to the change in motor speed and which part is due to the patient's respiratory cycle.

[0086] b) limit

[0087] Flow restriction can be used to determine a patient's respiratory cycle. Generally, the respiratory system will have a certain flow resistance (also called "restriction" or R), which can be used to indicate the change in system pressure p versus the square of the system's flow rate (Q). 2 The relationship between them is shown in the following formula.

[0088] p = RQ 2

[0089] Therefore, the restriction R can be approximated as:

[0090]

[0091] The restriction R can vary as the patient inhales and exhales. A smaller R value indicates a greater restriction (e.g., when the patient exhales).

[0092] Furthermore, the pressure p can also be approximated as a function of the motor speed, as shown in the following equation:

[0093] p = k m ω 2

[0094] Where ω corresponds to the motor speed, and k m This corresponds to a constant. Therefore, the restriction R can be approximated as:

[0095]

[0096] Thus, when using a varying R value as an indicator of a patient's respiratory cycle, the patient's respiratory cycle can be determined based on the measured flow rate Q and the measured motor speed ω. The constant k can be calculated using one or more pressure measurements. m The value of k, or we can assume k m The value of .

[0097] The pressure drop caused by the patient's respiratory and circulatory processes (inspiration / expiration) and the pressure drop caused by other factors (also known as systemic pressure drop) can be added together, as shown in the following equation:

[0098] k m ω 2 =k c Q 2 +RQ 2

[0099]

[0100] Where k c This corresponds to a constant associated with the system pressure drop. The detection of the patient's respiratory cycle is based on the deviation of the detected R (e.g., compared to the mean). The deviation (not the magnitude of R). Therefore, the constant k c It can be ignored. It can be... The value is tracked as a moving average to compensate for deviations in the limiting mechanism (e.g., due to irregular breathing, cannula movement, etc.) and to provide a smoother waveform.

[0101] c) System leak

[0102] The airflow generated by the blower can consist of a first portion flowing to the patient's lungs and a second portion leaking from the system (referred to as the "leak flow"). This can be expressed by the following equation:

[0103] Q = Q p +Q l

[0104] Q p Corresponding to the patient flow, and Q l This corresponds to the leakage flow.

[0105] Additionally, the pressure at the casing can be referred to as the "leakage pressure drop". The total blower pressure of the system can be approximated as the sum of the system pressure drop and the leakage pressure drop, which can be expressed as:

[0106]

[0107] Where k l Corresponding to the leakage constant. In a closed or sealed system, k lThis will be a constant. In a non-sealed system, k is a constant when the patient breathes. l It can vary over time, but can be considered essentially constant within a specific respiratory cycle. k l Characterized by "system leakage".

[0108] Therefore, the leakage flow can be approximated as:

[0109]

[0110] The pressure at the casing can be approximated as (Leakage pressure only) and the patient's lung flow can be approximated as Q. p =QQ l By observing changes in the patient's lung flow, the patient's respiratory and circulatory systems can be determined.

[0111] As mentioned above, variables Q and Q' can be measured, calculated, or estimated. p Q l k m and k c Additionally, k can be estimated by knowing that the average flow rate entering the patient's lungs will be approximated to zero for the purpose of providing respiratory assistance. l In other words, we can make the following assumptions: and The difference in the amount of gas inhaled and exhaled by the patient due to gas exchange (also known as "drift") can be calculated, allowing drift correction to be applied to the average flow rate. If the patient's respiratory cycle T is known, then the average leakage of the system can be approximated as:

[0112]

[0113] Then, the equation above can be used to calculate k. l If the period T is unknown, a time-weighted average can be used over a known number of breaths that are close to the period T.

[0114] Once the patient's respiratory cycle is determined (e.g., using any of the techniques disclosed above), control signals can be adjusted based on the patient's respiratory cycle. Additionally, the respiratory cycle can be used to calculate the patient's respiratory rate (e.g., respiratory counts per minute). The calculated respiratory rate can be displayed, stored, or transmitted (e.g., at display 308).

[0115] Pressure control in sealing systems

[0116] Pressure sensor readings can be obtained at the patient end or along a portion of the patient breathing tubing in a respiratory system having a sealed patient interface as described above. Pressure sensor readings can also be obtained within a flow therapy device. The pressure sensor can be placed anywhere in the flow path. A non-limiting example of a sealed patient interface is a NIV mask. The NIV mask can seal against the patient's face, resulting in virtually no system leakage. This allows for the measurement of the pressure of the gas delivered to the patient near or at the patient end. The pressure sensor can be positioned inside the NIV mask. The pressure sensor can be positioned outside the patient's nostrils. The pressure sensor can be positioned where the NIV mask is connected to the patient breathing tubing (such as...). Figure 1 The patient's breathing tube 16 is shown in the manifold.

[0117] Measurements from pressure sensors located near or at the patient end (such as those inside the NIV mask or along a portion of the patient's breathing tube) allow for the use of some of the equations described above to control the pressure delivered to the patient. Specifically, equation k m ω 2 =k c Q 2 +RQ 2 The pressure term RQ in 2 The pressure sensor reading P can be used instead to obtain the following equation.

[0118]

[0119] For this equation, we can assume that Q / ω is approximately constant because the system's operation does not change rapidly. This can be achieved by multiplying both sides of the equation by the term (Q / ω). 2 The equation can be further rearranged to obtain an expression that more clearly shows how the pressure sensor reading P and / or the system flow rate Q can affect the motor speed ω.

[0120]

[0121] Based on this equation, the desired system pressure can be achieved by controlling the motor speed. If the desired or predetermined system pressure is known, the required motor speed to achieve it can be calculated. The controller can then adjust the motor speed in the sealed breathing system to control the system pressure.

[0122] Increased respiratory and circulatory function

[0123] Once a patient's respiratory cycle is established, the control signal to the blower motor can be adjusted based on that cycle to better assist the patient's breathing. For example, flow therapy devices can assist a patient's respiratory cycle by increasing the airflow during inhalation and decreasing the flow during exhalation.

[0124] Figure 6A A block diagram of an example system for performing respiratory and circulatory enhancement for a flow therapy device is shown. Figure 6A As shown, patient 602 is connected to flow therapy device 604. Respiratory device 604 includes a blower motor 606 or other type of flow generator that can be used to provide airflow to patient 602.

[0125] During operation of the flow therapy device 604, multiple measurements can be acquired and transmitted to the control signal feedback module 610 to adjust the control signal to the blower motor 406 based on the respiratory cycle of the patient 602. For example, parameters of the blower motor 406 can be used to measure motor speed and / or system pressure. One or more flow sensors 608 can be used to monitor the airflow rate. The flow sensor 408 may include two or more different types of sensors, such as heated temperature sensing elements and ultrasonic sensor assemblies. Additionally, one or more additional sensors, such as pressure sensors (not shown), can be used to measure one or more additional measurements (e.g., pressure).

[0126] Multiple measurements (e.g., motor speed, flow rate, etc.) can be used to determine the patient's respiratory cycle at the respiratory cycle detection module 612. The determined respiratory cycle can be in the form of an alternating waveform (e.g., essentially a sine wave).

[0127] Once the patient's respiratory cycle is determined, it can be used to adjust the control signal to the blower motor 606. For example, the calculated respiratory cycle waveform from the respiratory cycle detection module 612 can be subjected to positive feedback 614 and / or negative feedback 616. Both positive feedback 614 and negative feedback 616 can be executed based on the calculated respiratory cycle and combined at 618 to generate a control signal for the blower motor 602.

[0128] Positive feedback 614 can be used to work in conjunction with the patient's respiratory cycle by decreasing the motor speed with the patient's exhalation and / or increasing the motor speed with the patient's inhalation. Based on the determined amplitude of the patient's inhalation / exhalation, one or more scaling parameters can be used to increase / decrease the amplitude of the control signal controlling the speed of the blower motor 406. For example, the positive feedback of the blower motor control signal can be expressed as:

[0129]

[0130] Where ω corresponds to the motor speed and R corresponds to the patient's limitation. as well as Corresponding to their average or baseline values, and k p This corresponds to the positive feedback parameter.

[0131] On the other hand, by suppressing changes in the control signal with the patient's inhalation or exhalation, negative feedback 616 can be used to limit the positive feedback provided to the patient's respiratory cycle. For example, with the patient's inhalation, the speed of the blower motor may only increase to a certain limit, even if the amplitude of the patient's inhalation increases. Negative feedback 616 can be optionally used only when the amplitude of the patient's inhalation or exhalation exceeds a threshold level. Negative feedback can be provided during inhalation but not exhalation, and vice versa.

[0132] Negative feedback can include limiting the positive feedback applied to the control signal to a certain limit. Negative feedback can include explicit terms such as:

[0133]

[0134] Where the negative feedback parameter k n And N is set so that when the deviation is limited At low (e.g., close to zero) levels, negative feedback is negligible, but as the bias increases, positive feedback begins to dominate. The amount of positive or negative feedback (e.g., the positive feedback parameter k) can be adjusted based on the patient's respiratory cycle (e.g., whether the patient is inhaling or expiring). p and negative feedback parameter k n (value).

[0135] Figure 7 A flowchart illustrating an example process for assisting a patient's respiratory cycle is shown. At box 702, a control signal is used to drive the blower motor associated with the flow therapy device.

[0136] At box 704, the patient's respiratory cycle is detected. Detecting the patient's respiratory cycle may include receiving multiple measurements from one or more sensors, such as flow rate measurements, motor speed measurements, pressure measurements, etc. The received measurements can be used to determine the patient's respiratory cycle, for example, using any of the techniques described above.

[0137] At box 706, it is determined whether the patient is currently inhaling or exhaling. If the patient is inhaling, at box 708, the control signal to the motor can be modified to increase the airflow to the patient, which may reduce the work of breathing the patient needs to do during inhalation. The increased airflow reduces the work of breathing. On the other hand, if the patient is exhaling, at box 710, the control signal to the motor can be modified to reduce the airflow to the patient. This may be beneficial to the patient because the work of breathing is reduced during exhalation because the patient does not need to inhale the incoming airflow. Additionally, noise caused by the collision between the patient's exhaled gas and the incoming gas from the cannula can be reduced. The ability to adjust the airflow based on the patient's inhalation / exhalation can enhance the effectiveness of high-flow-rate breathing therapy. For example, since the patient does not need to inhale the incoming airflow during exhalation, a considerably higher flow rate (e.g., during inhalation) can be delivered to provide greater dead zone flushing and / or CO2 flushing.

[0138] The amount of increase or decrease in airflow can be based on the amplitude of the patient's inhalation / exhalation. A combination of positive and negative feedback can be used to adjust the control signal. For example, positive feedback can be used to assist the patient's breathing by increasing the motor speed during inhalation and decreasing the motor speed during exhalation based on the amplitude of the patient's inhalation / exhalation, while negative feedback can be used to limit or mitigate the positive feedback applied to the motor control signal. The process can then return to block 702, where the updated control signal is used to drive the motor, and the patient's respiratory cycle continues to be monitored.

[0139] Although Figure 7 Feedback was demonstrated to be implemented during both the inspiratory and expiratory phases of the patient's respiratory cycle. However, as mentioned above, the positive or negative feedback parameters can be adjusted, at least in part, based on the patient's position in the respiratory cycle (e.g., whether the patient is inspiring or expiring). For example, positive feedback can be implemented during inspiration but not during expiration. For instance, a patient attempting to reduce their work by using "pursed-lip breathing" during expiration could benefit from assistance by increasing the flow rate with positive feedback during inspiration and decreasing the flow rate without positive feedback during expiration. By not implementing positive feedback during expiration, expiratory pressure and expiratory time can be increased, which may be beneficial for some patients.

[0140] Phase shift control loop

[0141] To assist the patient's breathing, the control signal used to drive the blower motor can be configured as a phase-locked loop with sensed patient breathing cycles, thereby synchronizing the control signal with the patient's breathing cycles.

[0142] Figure 6B A block diagram of a system for implementing a phase-locked control loop for a flow therapy device is shown. (Example) Figure 6BAs shown, patient 602 is connected to flow therapy device 404, and... Figure 6A Similar to the illustration. Blower motor 606 is configured to supply airflow to patient 602 according to a received control signal. The control signal controlling blower motor 606 may include an initial periodic waveform (e.g., a default waveform, or a waveform based on one or more patient measurements).

[0143] The blower motor 606 and flow sensor 608 can be configured to measure motor speed and flow rate, respectively (motor speed and flow rate can be received by control signal feedback module 610), wherein the patient's respiratory cycle can be determined at respiratory cycle detection module 612. The respiratory cycle may include a waveform.

[0144] Using the established respiratory cycle, the phase 620 of the patient's respiratory cycle waveform is determined and compared with the phase 626 of the applied control signal waveform 624 to enter a phase-locked control loop 622, which updates the phase of the applied control signal waveform 624. This repeatedly reduces the error between the phase of the applied control signal waveform 624 and the respiratory cycle waveform, ensuring that the applied control signal waveform 624 is substantially matched to the patient's respiratory cycle. For example, Figure 8 An example graph showing the patient's respiratory cycle waveform 802 and control signal waveform 804 is provided. The phase of the control signal 804 is compared with the phase of the respiratory cycle 802 to determine a phase mismatch 806. The phase of the control signal 804 can be repeatedly updated so that the phases of the control signal and the respiratory cycle are substantially synchronized (e.g., reducing phase mismatch 806). The phase of the control signal can be repeatedly updated until the phase mismatch is within a threshold amount (e.g., set time, phase percentage, etc.).

[0145] Additionally, the control signal is phase-shifted to produce a phase-shifted applied waveform 628. This phase-shifting compensates for the delay between the signal reaching the blower motor and the resulting flow received by the patient. The waveform can be phase-shifted to preempt the patient's respiratory cycle. For example, the control signal can be configured to slightly increase the speed of the blower motor before the patient begins inspiration and slightly decrease the speed of the blower motor before the patient begins expiration. This provides a predictive system, rather than a strictly reactive system, allowing for a more comfortable respiratory transition as the patient inhales and exhales.

[0146] Figure 9 A flowchart illustrating an example process for implementing control signals for a blower motor into a phase-locked loop with sensed patient respiratory cycles is shown. At box 902, control signals are used to drive the blower motor associated with the flow therapy device.

[0147] At box 904, the patient's respiratory cycle is detected. Detecting the patient's respiratory cycle may include receiving multiple measurements from one or more sensors, such as flow rate measurements, motor speed measurements, pressure measurements, etc. The received measurements can be used to determine the patient's respiratory cycle, for example, using any of the techniques described above. Additionally, the respiratory rate or frequency can be calculated based on the determined respiratory cycle.

[0148] The controller can estimate the respiratory rate in several ways. The controller can estimate the respiratory rate during initial startup and / or during operation. The respiratory rate can be estimated by counting the zero-crossings of any type of respiratory signal described herein. The respiratory rate can be estimated by employing a Fast Fourier Transform (FFT) of the respiratory signal and finding the dominant frequency. The respiratory rate can be estimated by finding the zero-crossings or peaks of the autocorrelation of the respiratory signal.

[0149] Autocorrelation can be a comparison of a signal with a delayed copy of itself, as a function of delay. Autocorrelation can reveal recurring patterns, for example, hidden in the original waveform of a signal by noise. Specifically, it can be a graph of a patient's original flow rate readings versus time (such as...) measured by the system. Figure 14A The curve shown can be autocorrelated, such as... Figure 14B As shown, the peak of the autocorrelation can be identified. This peak can be the estimated respiratory cycle, which can be used to estimate the patient's respiratory rate, also known as respiratory velocity. The respiratory cycle can also be determined by identifying the zero-crossing points of the autocorrelation. Compared to applying it directly to the original respiratory signal waveform, autocorrelation (especially the first few cycles) can provide a more noise-robust estimate of the respiratory cycle. This is because edge detection can be unstable on the original waveform due to noise.

[0150] Besides helping to determine respiratory rate or frequency for implementing the blower motor control signal as a phase-locked loop, respiratory rate information extracted from autocorrelation can also be used to provide consistency information. For example, the extracted respiratory rate information can indicate whether the patient is using the system correctly. The extracted respiratory rate information can indicate the work of breathing.

[0151] At box 906, it is determined whether the phase of the control signal matches the phase of the sensed patient respiratory cycle. This determination is satisfied if the phase of the control signal is within a threshold amount or percentage of the phase of the sensed patient respiratory cycle. The phase difference between the control signal and the sensed patient waveform can be determined in a similar manner to that described above for estimating respiratory rate. For example, the controller can perform a cross-correlation between the control signal and the sensed patient waveform and look for a peak in the cross-correlation. The peak may appear or substantially appear at the time delay between the two waveforms.

[0152] If it is determined that the phase of the control signal does not match the phase of the sensed patient's respiratory cycle, then at box 908, the phase of the control signal is repeatedly adjusted to match the phase of the sensed patient's respiratory cycle. The phase adjustment of the control signal can be a predetermined amount, a predetermined percentage, a percentage or amount based on the difference between the phase of the control signal and the phase of the sensed patient's respiratory cycle, etc. The process can then return to box 902, where the motor can continue to be driven by the control signal, and the patient's respiratory cycle can continue to be monitored.

[0153] The amplitude of the control signal can be based on one or more positive or negative feedback parameters. For example, the amplitude of a patient's inspiration or expiration can be measured and used to determine the amplitude of the control signal waveform using both positive and negative feedback parameters.

[0154] By implementing a phase-locked loop (PLL), synchronization between the control signal and the patient's respiratory cycle can be achieved, allowing for a more comfortable respiratory transition with each inhalation and exhalation. When asynchrony is suspected, positive feedback can be reduced or eliminated. In such cases, the control signal can be configured to reduce the peak flow rate or to maintain a substantially constant flow rate, where the constant flow rate is lower than the flow rate when positive feedback is implemented. Reducing or eliminating positive feedback can reduce or eliminate potential patient discomfort due to the positive feedback to the control signal. Once synchronization between the control signal and the patient's respiratory cycle is re-established, positive feedback can be restarted or increased.

[0155] Once synchronization is achieved, control signal waveforms can be gradually introduced. For example, the amplitude of the control signal waveform can start at a low value so that the slightly out-of-phase control signal waveform with the patient's respiratory cycle does not cause too much discomfort to the patient. As synchronization is achieved, the amplitude of the control signal waveform can be increased.

[0156] The control signal waveform can be configured to achieve a target phase difference relative to the patient's respiratory cycle. For example, the control signal waveform can be a target phase shift relative to the respiratory cycle to compensate for system delays or preempt the patient's respiratory cycle. These implementations are discussed in more detail below.

[0157] A delay may be sensed between the time it takes for the control signal to be delivered to the blower motor and the time it takes for the blower motor to generate the resulting airflow (due to factors such as motor acceleration or deceleration, delay due to inertia, sensed delay, etc.), which is referred to below as system delay. The control signal can be phase-shifted to compensate for this system delay. Figure 10 A flowchart illustrating an example process for phase-shifting a control signal to compensate for system delay is shown. At box 1002, the control signal is used to drive the blower motor associated with the flow therapy device.

[0158] At box 1004, one or more sensors can be used to sense the resulting flow rate from the blower motor. The one or more sensors may include a heated temperature sensing element, an ultrasonic sensor, etc. Based on the measured flow rate, a system delay is determined between the time the blower motor receives a control signal and the time the resulting flow rate is sensed.

[0159] At box 1006, the control signal is adjusted based on the determined system delay. For example, Figure 11 A graph illustrating the updating of the control signal to compensate for system delay is shown. The system delay 1106 is measured between the time the motor receives the control signal 1102 and the time the patient receives the resulting flow 1104. The control signal can then be phase-shifted to form a phase-shifted control signal 1108 to compensate for the delay 1106.

[0160] The control waveform can be further shifted to allow it to sense the respiratory cycle waveform first. Figure 12 A flowchart illustrating an example process for configuring control signals to preemptively project the patient's respiratory cycle waveform is shown. At box 1202, control signals are used to drive the blower motor associated with the flow therapy device.

[0161] At box 1204, the patient's respiratory cycle is detected. Detecting the patient's respiratory cycle may include receiving multiple measurements from one or more sensors, such as flow rate measurements, motor speed measurements, pressure measurements, etc. The received measurements can be used to determine the patient's respiratory cycle, for example, using any of the techniques described above.

[0162] At box 1206, the phase of the control signal can be matched with the phase of the respiratory cycle. This can include an iterative process, such as the one described above. Figure 8 and / or Figure 9 The iterative process described.

[0163] In box 1208, the patient's respiratory cycle is analyzed to identify when the patient inhales or exhales. For example, Figure 13 An example diagram showing the patient's respiratory cycle 1302 and the phase shift control signal 1304 is presented. (See diagram below.) Figure 13 As shown, it can be inferred that the patient begins exhalation at 1306 near the peak of the patient's respiratory cycle waveform (e.g., shortly after the peak) and begins inhalation at 1308 near the trough of the respiratory cycle waveform (e.g., shortly after the trough).

[0164] Back Figure 12 At box 1210, the control signal is phase-shifted based on the patient's respiratory cycle. For example, the control signal can be phase-shifted so that it leads the respiratory cycle by a set amount of phase or time. For example, as... Figure 13As shown, the control waveform can be shifted so that the motor begins to decrease in speed before the patient begins to exhale and begins to increase in speed before the patient begins to inhale.

[0165] The control waveform can be selected from a series of predetermined shapes and can be modified based on one or more respiratory parameters (e.g., the amplitude of the respiratory cycle waveform). The control waveform can be dynamically created based on the sensed respiratory waveform.

[0166] Unless the context explicitly requires otherwise, throughout the specification and claims, the terms "comprise / comprising" should be interpreted in a inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0167] The term “about” is used here to indicate within the standard measurement accuracy.

[0168] Any reference to prior art in this specification is not, and should not be construed as, an admission or in any way an implication that such prior art constitutes part of common general knowledge in any country of the world.

[0169] The disclosed devices and systems may also be said in a broad sense to exist individually or collectively in any or all combinations of the components, elements and features mentioned or indicated in the specification of this application, as well as two or more of the said components, elements or features.

[0170] Where integers or components with known equivalents are mentioned in the preceding description, these integers are introduced here as if listed separately.

[0171] Some actions, events, or functions of any algorithm, method, or process described herein may be performed in a different order, or may be added, combined, or omitted entirely (e.g., not all described actions or events are necessary for the practical algorithm). Furthermore, actions or events may be performed concurrently, for example, through multithreading, interrupt handling, or on multiple processors or processor cores or other parallel architectures, rather than sequentially.

[0172] It should be noted that various changes and modifications based on this disclosure will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the disclosed equipment and systems and without diminishing their associated advantages. For example, multiple different components may be repositioned as needed. Therefore, it is intended that such changes and modifications be included within the scope of the disclosed equipment and systems. Furthermore, not all features, aspects, and advantages are necessary for practicing the disclosed equipment and systems. Therefore, the scope of the disclosed equipment and systems is intended to be defined solely by the following claims.

Claims

1. A high-flow-rate respiratory assist device configured to adjust the flow rate of respiratory gases according to the patient's inhalation and exhalation, the respiratory assist device comprising: A blower, which includes a motor; First and second types of sensors used for measuring flow rate; The first type of sensor includes a heated temperature sensing element, and the second type of sensor includes an ultrasonic flow sensor. The respiratory assist device is configured for use in non-sealed breathing systems. as well as The processor is configured as follows: Use at least one of the following, based at least on this flow rate, to determine the predicted patient inspiratory and expiratory cycles. a) Flow rate deviation of the breathing gas flow rate relative to the setpoint flow rate value. b) Restriction of breathing gases, specifically the resistance to breathing gases in high-flow-rate ventilators. c) System leakage of breathing gas from high-flow-rate breathing aids. The flow rate is determined based on the outputs of two types of sensors, and Adjust the flow rate of the breathing gas according to the patient's breathing.

2. The respiratory assist device as described in claim 1, wherein, The processor is configured to adjust the flow rate of breathing gas based at least in part on a bistable system that uses both positive and negative feedback.

3. The respiratory assist device as described in claim 1 or 2, wherein, The processor determines the predicted patient inspiratory and expiratory cycles based on the flow rate and a signal indicating the speed of the blower motor, which is configured to provide a signal indicating the speed of the blower motor.

4. The respiratory assist device as described in claim 1 or 2 further includes a pressure sensor, wherein, The processor is configured to determine the predicted patient inspiratory and expiratory cycles based at least in part on the flow rate and pressure.

5. The respiratory assist device as described in claim 1 or 2, wherein, The processor is configured to adjust the flow rate of respiratory gases based on the predicted amplitude of inhalation and exhalation.

6. The respiratory assist device as described in claim 1 or 2, wherein, The processor is configured to determine the predicted current flow rate based on a previously determined flow rate and a second flow rate output from a second type of flow sensor.

7. The respiratory assist device as described in claim 6, wherein, The predicted current flow rate is updated using one or more outputs from the first type of sensor in order to determine the final flow rate.

8. The respiratory assist device as described in claim 1 or 2, wherein, The ultrasonic flow sensor includes a first ultrasonic transducer and a second ultrasonic transducer.

9. The respiratory assist device as described in claim 1 or 2, wherein, Inhalation and exhalation are determined based on the established flow rate.

10. The respiratory assist device as described in claim 1 or 2, wherein, The processor is configured as follows: If the flow rate increases from the setpoint value, it is determined to be inhalation; and If the flow rate decreases from the setpoint flow rate value, it is determined to be exhalation.

11. A high-flow-rate system configured to adjust the flow rate of respiratory gases according to a patient's inhalation and exhalation, the high-flow-rate system comprising: Blower; A first type of sensor and a second type of sensor are used to measure flow rate, wherein the flow rate is determined based on the output of both types of sensors. The first type of sensor includes a heated temperature sensing element, and the second type of sensor includes an ultrasonic flow sensor; and The processor is electrically connected to multiple sensors, including the two types of sensors described above, and is configured as follows: The system receives a first input and a second input from the multiple sensors. The first input corresponds to the measured flow rate, and the second input is a signal indicating the speed of the blower motor or pressure from a pressure sensor. The predicted patient inspiratory and expiratory cycles are determined based on at least one of the following, using a first input and a second input: a) Flow rate deviation of the breathing gas flow rate relative to the setpoint flow rate value. b) Restriction of breathing gases, which is the resistance to breathing gases in high-flow-rate systems. c) System leakage of breathing gas from high-flow-rate systems; and Adjust the flow rate of respiratory gases based on the predicted patient inspiratory and expiratory cycles; This high-flow system is configured for use in non-sealed breathing systems.

12. The high-flow-rate system as described in claim 11, wherein, The processor is configured to adjust the flow rate of breathing gas based at least in part on a bistable system that uses both positive and negative feedback.

13. The high-flow-rate system as described in claim 11 or 12, wherein, When the second input is a signal indicating the speed of the blower motor, the processor is further configured to receive a third input, which includes pressure.

14. The high-flow-rate system as described in claim 11 or 12, wherein, The processor is configured to adjust the flow rate of respiratory gases based on the predicted amplitude of inhalation and exhalation.

15. The high-flow-rate system as described in claim 11 or 12, wherein, The processor is configured to determine the predicted current flow rate based on a previously determined flow rate and a second flow rate output from a second type of sensor.

16. The high-flow-rate system as described in claim 15, wherein, The predicted current flow rate is updated using one or more outputs from the first type of sensor in order to determine the final flow rate.

17. The high-flow-rate system as described in claim 11 or 12, wherein, The ultrasonic flow sensor includes a first ultrasonic transducer and a second ultrasonic transducer.

18. The high-flow-rate system as described in claim 11 or 12, wherein, Inhalation and exhalation are determined based on the established flow rate.

19. The high-flow-rate system as described in claim 11 or 12, wherein, The processor is configured as follows: If the flow rate increases from the setpoint value, it is determined to be inhalation; and If the flow rate decreases from the setpoint flow rate value, it is determined to be exhalation.

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