Alarm for respiratory therapy system

Abstract

A breathing assistance device is disclosed that includes a flow generator configured to provide breathing gases to a patient, the breathing gases including supplemental oxygen provided from an oxygen source. The breathing assistance device controller is configured to determine a target oxygen concentration of the breathing gas and calculate an estimated future value of the patient blood oxygen concentration based on a difference between the initial oxygen concentration of the breathing gas and the target oxygen concentration of the breathing gas and the patient blood oxygen concentration.

Description

[0001] Divisional application

[0002] This application is a divisional application of application number 202080074633.0, filed on July 2, 2020, entitled “Alarm for a respiratory therapy system”. TECHNICAL FIELD

[0003] The present invention relates to methods and systems for controlling and / or operating a respiratory assistance device. BACKGROUND

[0004] Respiratory devices are used in various environments, such as hospitals, medical facilities, home care, or home environments, to deliver a flow of gas to a user or patient. Respiratory devices, such as flow therapy devices, can include an oxygen inlet to allow supplemental oxygen to be delivered with the flow of gas, and / or a humidification device to deliver heated and humidified gas. Flow therapy devices can allow for adjustment and control of properties of the flow of gas, including flow rate, temperature, gas concentration (such as oxygen concentration), humidity, pressure, and the like. SUMMARY

[0005] One or more inventions relating to a respiratory assistance device for providing respiratory gases to a patient are disclosed.

[0006] In one aspect, there is provided a respiratory assistance device, comprising:

[0007] a flow generator configured to provide respiratory gases to a patient, the respiratory gases comprising supplemental oxygen provided from an oxygen source,

[0008] a controller configured to control an oxygen concentration of the respiratory gases,

[0009] at least one sensor configured to provide a measurement indicative of a blood oxygen concentration of the patient to the controller,

[0010] wherein the controller is configured to determine a target oxygen concentration of the respiratory gases,

[0011] wherein the controller is configured to calculate an estimated future value of the blood oxygen concentration of the patient based on:

[0012] a difference between an initial oxygen concentration of the respiratory gases and the target oxygen concentration of the respiratory gases, and

[0013] the measurement indicative of the blood oxygen concentration of the patient.

[0014] In some embodiments, the controller is configured to control the oxygen concentration of the respiratory gases based on the target oxygen concentration.

[0015] In some embodiments, the estimated future value of the patient's blood oxygen concentration is further based on the time since the controller began to control the oxygen concentration of these respiratory gases to the target oxygen concentration.

[0016] In some embodiments, the controller is configured to receive input and determine the target oxygen concentration of these respiratory gases based on the input.

[0017] In some embodiments, the input includes a target oxygen concentration range, which includes an upper target oxygen concentration and a lower target oxygen concentration.

[0018] In some embodiments, the humidifier, controller, flow generator, and breathing assist sensor are housed in a single housing.

[0019] In some embodiments, the device includes at least one gas composition sensor configured to provide a controller with a measurement indicating the oxygen concentration of the breathing gas.

[0020] In some embodiments, at least one gas composition sensor is an ultrasonic sensor.

[0021] In some embodiments, the controller is configured to compare the estimated future value of the patient's blood oxygen concentration with a blood oxygen concentration alarm threshold and / or a blood oxygen concentration alarm range, and to generate an alarm output if the estimated future value of the patient's blood oxygen concentration is not within the blood oxygen concentration alarm range.

[0022] In some embodiments, the blood oxygen concentration alarm range includes an upper blood oxygen concentration alarm threshold and a lower blood oxygen concentration alarm threshold.

[0023] In some embodiments, the blood oxygen concentration alarm threshold is determined based on the time elapsed since the controller began to control the oxygen concentration of these respiratory gases to the target oxygen concentration.

[0024] In some embodiments, the alarm threshold may be determined based on the amount of change in the target oxygen concentration.

[0025] In some embodiments, the alarm threshold may be determined based on the target oxygen concentration.

[0026] In some embodiments, the alarm threshold may be determined based on the current oxygen concentration in the gas.

[0027] In some embodiments, the alarm threshold is based on the target blood oxygen concentration.

[0028] In some embodiments, the controller is configured to generate an alarm output based on an estimated future value of the patient's blood oxygen concentration and a comparison with a blood oxygen concentration alarm threshold.

[0029] In some embodiments, the controller is configured to generate the alarm output if an estimated future value of the patient blood oxygen concentration is above or below the blood oxygen concentration threshold.

[0030] In some embodiments, the alarm threshold is based on a time since the controller started controlling the oxygen concentration of the breathing gas to the target oxygen concentration.

[0031] In some embodiments, the input comprises a target blood oxygen concentration, and the blood oxygen concentration alarm range is based on the target blood oxygen concentration.

[0032] In some embodiments, the blood oxygen concentration threshold and / or the blood oxygen concentration alarm range is based on a difference between the target oxygen concentration and an upper target oxygen concentration.

[0033] In some embodiments, the breathing assistance device can comprise at least one valve, wherein the controller is configured to control the valve to control the oxygen concentration of the breathing gas by varying an amount of oxygen provided to the breathing gas from an oxygen source.

[0034] In some embodiments, the breathing assistance device can be connected to an oxygen supply, wherein the controller is configured to control a flow of gas from the oxygen supply to control the oxygen concentration of the breathing gas.

[0035] In some embodiments, the controller is configured to control the oxygen concentration of the breathing gas based on the target oxygen concentration and a measured oxygen concentration of the breathing gas.

[0036] In some embodiments, measurements indicative of the patient blood oxygen concentration can be determined over a predetermined time.

[0037] In some embodiments, the controller is configured to generate the alarm output based on an estimated future value of the patient blood oxygen concentration.

[0038] In some embodiments, the breathing assistance device (or related apparatus) is configured to display the alarm output or information related to the alarm output.

[0039] In some embodiments, the breathing assistance device (or related apparatus) is configured to display an estimated future value of the patient blood oxygen concentration.

[0040] In some embodiments, the alarm output can be transmitted to one or more servers in communication with the breathing assistance device, or a patient monitoring unit, and / or a nurse monitoring station.

[0041] In another aspect, there is provided a breathing assistance device, the breathing assistance device comprising:

[0042] a flow generator configured to provide breathing gas to a patient, the breathing gas comprising supplemental oxygen provided from an oxygen source,

[0043] at least one sensor configured to provide, to the controller, a measurement indicative of a blood oxygen concentration of the patient,

[0044] a controller configured to receive an input, the input comprising a target oxygen concentration range, the target oxygen concentration range comprising an upper target oxygen concentration and / or a lower target oxygen concentration,

[0045] a controller configured to control the oxygen concentration of the respiratory gases to a target oxygen concentration, wherein the target oxygen concentration is within the target oxygen concentration range comprising the upper target oxygen concentration and the lower target oxygen concentration,

[0046] wherein the controller is configured to:

[0047] calculate, based on the measurement indicative of a blood oxygen concentration of the patient and a difference between the target oxygen concentration and the upper target oxygen concentration, an estimated maximum future value of the blood oxygen concentration of the patient for the target oxygen concentration range, or

[0048] calculate, based on the measurement indicative of a blood oxygen concentration of the patient and a difference between the target oxygen concentration and the lower target oxygen concentration, an estimated minimum future value of the blood oxygen concentration of the patient for the target oxygen concentration range.

[0049] In some embodiments, the controller is configured to control the oxygen concentration of the respiratory gases from an initial oxygen concentration to the target oxygen concentration.

[0050] In some embodiments, the initial oxygen concentration is an oxygen concentration prior to the controller controlling the oxygen concentration of the respiratory gases to the target oxygen concentration.

[0051] In some embodiments, the respiratory assistance device is configured to receive an input indicative of a target oxygen concentration range.

[0052] In some embodiments, the target oxygen concentration range is input via a user interface.

[0053] In some embodiments, the estimated maximum future value and / or the estimated minimum future value is based on an estimated oxygen efficiency.

[0054] In some embodiments, the estimated maximum future value and / or the estimated minimum future value is updated in real-time.

[0055] In some embodiments, the maximum or minimum future value is after an effect of a change in oxygen concentration on the blood oxygen of the patient has occurred.

[0056] In some embodiments, the controller is configured to display an estimated minimum future value of the patient blood oxygen and / or an estimated minimum future value of the patient blood oxygen concentration.

[0057] In some embodiments, the controller is configured to generate an alarm output.

[0058] In some embodiments, the alarm output can be transmitted to one or more servers in communication with the respiratory assistance device, or a patient monitoring unit, and / or a nurse monitoring station.

[0059] In some embodiments, the alarm output comprises at least one alarm parameter.

[0060] In some embodiments, the controller is configured to generate the alarm output based on an estimated future value of the patient blood oxygen concentration and / or an estimated maximum or minimum future value of the patient blood oxygen concentration.

[0061] In some embodiments, the controller is configured to compare the estimated maximum future value of the patient blood oxygen concentration to an upper target blood oxygen concentration and generate the alarm output if the estimated maximum future value of the patient blood oxygen concentration is less than the upper target blood oxygen concentration.

[0062] In some embodiments, the alarm parameter or alarm output is based on a magnitude of a difference between the estimated maximum future value of the patient blood oxygen concentration and the upper target blood oxygen concentration.

[0063] In some embodiments, the controller is configured to compare the estimated minimum future value of the patient blood oxygen concentration to a lower target blood oxygen concentration and generate the alarm output if the estimated minimum future value of the patient blood oxygen concentration is less than the lower target blood oxygen concentration.

[0064] In some embodiments, the alarm parameter or alarm parameter of the alarm output is based on a magnitude of a difference between the estimated minimum future value of the patient blood oxygen concentration and the lower target blood oxygen concentration.

[0065] In some embodiments, the alarm parameter is an alarm time or an alarm intensity.

[0066] In some embodiments, the alarm output and / or related data is provided to a display.

[0067] In some embodiments, the alarm output is configured to present a message on the display.

[0068] In some embodiments, the alarm output is configured to produce a sound or provide an indication.

[0069] In another aspect, there is provided a respiratory assistance device, the respiratory assistance device comprising:

[0070] a flow generator configured to provide breathing gas to a patient, the breathing gas comprising supplemental oxygen provided from an oxygen source,

[0071] at least one sensor configured to provide a measurement indicative of the patient's blood oxygen concentration to the controller,

[0072] wherein, during operation of the apparatus, the controller is configured to store breathing gas oxygen concentration data, wherein the stored breathing gas oxygen concentration data comprises: a plurality of oxygen concentrations of breathing gas, each oxygen concentration of the breathing gas having an associated time stamp,

[0073] wherein the controller is configured to calculate an estimated future value of the patient's blood oxygen concentration based on:

[0074] the stored breathing gas oxygen concentration data, wherein the oxygen concentrations of the breathing gas are weighted based on the associated time stamps, and

[0075] the measurement indicative of the patient's blood oxygen concentration.

[0076] In some embodiments, the controller is configured to calculate an estimated future value of the patient's blood oxygen concentration based on:

[0077] the estimated oxygen efficiency ratio of the patient,

[0078] a hemoglobin saturation function.

[0079] In some embodiments, the controller is configured to generate an alert output based on the estimated future value of the patient's blood oxygen concentration.

[0080] In some embodiments, the breathing assistance apparatus (or related device) is configured to display the alert output or information related to the alert output.

[0081] In some embodiments, the breathing assistance apparatus (or related device) is configured to display the estimated future value of the patient's blood oxygen concentration.

[0082] In some embodiments, the alert output can be transmitted to one or more servers in communication with the breathing assistance apparatus, or a patient monitoring unit, and / or a nurse monitoring station.

[0083] In another aspect, there is provided a breathing assistance apparatus, the breathing assistance apparatus comprising:

[0084] a flow generator configured to provide breathing gas to a patient, the breathing gas comprising supplemental oxygen provided from an oxygen source,

[0085] at least one sensor configured to provide, to the controller, a measurement indicative of a blood oxygen concentration of the patient,

[0086] wherein, during operation of the apparatus, the controller is configured to store respiratory gas oxygen concentration data, wherein the stored respiratory gas oxygen concentration data comprises one or more oxygen concentrations of the respiratory gases, each oxygen concentration of the respiratory gases having an associated time stamp,

[0087] wherein the controller is configured to calculate an estimated maximum future value of the blood oxygen concentration of the patient based on:

[0088] the stored respiratory gas oxygen concentration data, wherein the oxygen concentrations of the respiratory gases are weighted based on the associated time stamps, and

[0089] the measurement indicative of the blood oxygen concentration of the patient,

[0090] a difference between the current oxygen concentration of the respiratory gases and an upper target oxygen concentration.

[0091] In some embodiments, the controller is configured to calculate an estimated maximum future value of the blood oxygen concentration of the patient based on:

[0092] an estimated oxygen efficiency ratio of the patient,

[0093] a hemoglobin saturation function.

[0094] In another aspect, there is provided a respiratory assistance apparatus, the respiratory assistance apparatus comprising:

[0095] a flow generator configured to provide respiratory gases to a patient, the respiratory gases comprising supplemental oxygen provided from an oxygen source,

[0096] at least one sensor configured to provide, to the controller, a measurement indicative of a blood oxygen concentration of the patient,

[0097] wherein, during operation of the apparatus, the controller is configured to store respiratory gas oxygen concentration data, wherein the stored respiratory gas oxygen concentration data comprises one or more oxygen concentrations of the respiratory gases, each oxygen concentration of the respiratory gases having an associated time stamp,

[0098] wherein the controller is configured to calculate an estimated minimum future value of the blood oxygen concentration of the patient based on:

[0099] the stored respiratory gas oxygen concentration data, wherein the oxygen concentrations of the respiratory gases are weighted based on the associated time stamps, and

[0100] the measurement indicative of the patient's blood oxygen concentration,

[0101] a difference between the oxygen concentration of the respiratory gas of the current estimation phase and a lower target oxygen concentration.

[0102] In some embodiments, the controller is configured to calculate an estimated minimum future value of the patient's blood oxygen concentration based on:

[0103] an estimated oxygen efficiency ratio of the patient,

[0104] a haemoglobin saturation function.

[0105] In some embodiments, the relevant time stamp comprises a time at which the relevant oxygen concentration of the respiratory gas was recorded, and / or measured and / or stored.

[0106] In some embodiments, the relevant time stamp comprises a time elapsed since the relevant oxygen concentration of the respiratory gas was recorded, and / or measured and / or stored.

[0107] In some embodiments, the controller is configured to determine a series of changes in the oxygen concentration of the respiratory gas in the stored respiratory gas oxygen concentration data.

[0108] In some embodiments, the oxygen concentration of the respiratory gas is controlled to a target oxygen concentration of the respiratory gas.

[0109] In some embodiments, the oxygen concentration of the respiratory gas is a measured oxygen concentration of the respiratory gas.

[0110] In some embodiments, the apparatus comprises at least one gas composition sensor configured to provide a measurement indicative of the oxygen concentration of the respiratory gas to the controller.

[0111] In some embodiments, the controller is configured to update the stored oxygen concentrations of the respiratory gas concentration data at regular time intervals or irregular time intervals.

[0112] In some embodiments, the controller is configured to update the stored respiratory gas oxygen concentration when a target oxygen concentration of the respiratory gas is updated by the controller.

[0113] In some embodiments, the weighting based on the relevant time stamp is based on a decay function.

[0114] In some embodiments, the stored oxygen concentration data is transmitted to one or more servers in communication with the respiratory assistance apparatus, or a patient monitoring unit, and / or a nurse monitoring station.

[0115] In another aspect, there is provided a respiratory assistance apparatus comprising:

[0116] a flow generator configured to provide breathing gas to a patient, the breathing gas comprising supplemental oxygen provided from an oxygen source,

[0117] at least one sensor configured to provide a measurement indicative of the patient's blood oxygen concentration to the controller,

[0118] wherein the controller is configured to maintain a sum of changes in the breathing gas oxygen concentration,

[0119] wherein the controller is configured to perform an estimation update phase, the estimation update phase comprising:

[0120] applying a decay function to the sum of changes in the breathing gas oxygen concentration,

[0121] computing a difference between the current estimation update phase breathing gas oxygen concentration and the previous estimation update phase breathing gas,

[0122] adding the difference to the sum of changes in the breathing gas oxygen concentration,

[0123] wherein the controller is configured to compute an estimated future value of the patient's blood oxygen concentration based on:

[0124] the sum of changes in the breathing gas oxygen concentration, and

[0125] the measurement indicative of the patient's blood oxygen concentration.

[0126] a controller configured to compute an estimated future value of a patient's blood oxygen concentration based on:

[0127] the patient's estimated oxygen efficiency ratio,

[0128] a hemoglobin saturation function.

[0129] In another aspect, there is provided a breathing assistance apparatus, the breathing assistance apparatus comprising:

[0130] a flow generator configured to provide breathing gas to a patient, the breathing gas comprising supplemental oxygen provided from an oxygen source,

[0131] at least one sensor configured to provide a measurement indicative of the patient's blood oxygen concentration to the controller,

[0132] wherein the controller is configured to maintain a sum of changes in the breathing gas oxygen concentration,

[0133] wherein the controller is configured to perform an estimation update phase, the estimation update phase comprising:

[0134] applying an attenuation function to the sum of changes in oxygen concentration of the respiratory gases,

[0135] calculating a difference between the oxygen concentration of the respiratory gases at the current estimation update phase and the respiratory gases at a previous estimation update phase,

[0136] adding the difference to the sum of changes in oxygen concentration of the respiratory gases,

[0137] wherein the controller is configured to calculate the estimated maximum future value of the patient blood oxygen concentration based on:

[0138] the sum of changes in oxygen concentration of the respiratory gases, and

[0139] the measurement indicative of the patient blood oxygen concentration,

[0140] a difference between the oxygen concentration of the respiratory gases at the current estimation phase and an upper target oxygen concentration.

[0141] In some embodiments, the controller is configured to calculate the estimated maximum future value of the patient blood oxygen concentration based on:

[0142] the estimated oxygen efficiency ratio of the patient,

[0143] a haemoglobin saturation function.

[0144] In another aspect, there is provided a respiratory assistance apparatus comprising:

[0145] a flow generator configured to provide respiratory gases to a patient, the respiratory gases comprising supplemental oxygen provided from an oxygen source,

[0146] at least one sensor configured to provide a measurement indicative of a patient blood oxygen concentration to the controller,

[0147] wherein the controller is configured to maintain a sum of changes in respiratory gas oxygen concentration,

[0148] wherein the controller is configured to perform an estimation update phase, the estimation update phase comprising:

[0149] applying an attenuation function to the sum of changes in oxygen concentration of the respiratory gases,

[0150] calculating a difference between the oxygen concentration of the respiratory gases at the current estimation update phase and the respiratory gases at the previous estimation update phase,

[0151] adding the difference to the sum of changes in oxygen concentration of the respiratory gases,

[0152] wherein the controller is configured to calculate an estimated minimum future value of the patient blood oxygen concentration based on:

[0153] a sum of changes in the oxygen concentration of the respiratory gases, and

[0154] the measurement indicative of the patient blood oxygen concentration,

[0155] a difference between the current estimated oxygen concentration of the respiratory gases and a lower target oxygen concentration.

[0156] In some embodiments, the controller is configured to calculate an estimated minimum future value of the patient blood oxygen concentration based on:

[0157] the estimated oxygen efficiency ratio of the patient,

[0158] a hemoglobin saturation function.

[0159] In some embodiments, the controller is configured to perform the estimation update phase at regular time intervals or irregular time intervals.

[0160] In some embodiments, the controller is configured to perform the estimation update in real time.

[0161] In some embodiments, the controller is configured to perform the estimation update phase periodically.

[0162] In some embodiments, the controller is configured to perform the estimation update phase when a target oxygen concentration of the respiratory gases is updated by the controller.

[0163] In some embodiments, the controller is configured to control the oxygen concentration of the respiratory gases to a target oxygen concentration,

[0164] In some embodiments, the oxygen concentration of the respiratory gases is controlled to a target oxygen concentration of the respiratory gases.

[0165] In some embodiments, the oxygen concentration of the respiratory gases is a measured oxygen concentration of the respiratory gases.

[0166] In some embodiments, the apparatus comprises at least one gas composition sensor configured to provide a measurement indicative of the oxygen concentration of the respiratory gases to the controller.

[0167] In some embodiments, the controller is configured to update a target oxygen concentration of the respiratory gases and control the oxygen concentration of the respiratory gases from an initial oxygen concentration to the target oxygen concentration.

[0168] In some embodiments, the target oxygen concentration is provided by an oxygen concentration controller.

[0169] In some embodiments, the input or input further comprises a target blood oxygen concentration.

[0170] In some embodiments, the target blood oxygen concentration or target blood oxygen concentration is a range.

[0171] In some embodiments, the target blood oxygen concentration comprises an upper target blood oxygen concentration and / or a lower target blood oxygen concentration.

[0172] In some embodiments, the controller is configured to determine the target oxygen concentration based on a mid-value of the target blood oxygen concentration range.

[0173] In some embodiments, the controller is configured to control the target blood oxygen concentration to be within the upper target blood oxygen concentration and the lower target blood oxygen concentration.

[0174] In some embodiments, the controller is configured to vary the target oxygen concentration to control the patient blood oxygen concentration to the target blood oxygen concentration.

[0175] In some embodiments, the controller is configured to vary the amount of supplemental oxygen provided to the breathing gas from an oxygen source to control the oxygen concentration of the breathing gas.

[0176] In some embodiments, the apparatus comprises at least one valve tuning arrangement.

[0177] In some embodiments, the valve tuning arrangement is in fluid communication with the blower.

[0178] In some embodiments, the valve tuning arrangement is controllable to adjust the amount of oxygen in the incoming gas stream.

[0179] In some embodiments, the controller is configured to generate an alarm output.

[0180] In some embodiments, the alarm output can be transmitted to one or more servers in communication with the respiratory assistance apparatus, or a patient monitoring unit, and / or a nurse monitoring station.

[0181] In some embodiments, the alarm output comprises at least one alarm parameter.

[0182] In some embodiments, the controller is configured to generate the alarm output based on an estimated future value of the patient blood oxygen concentration and / or an estimated maximum or minimum future value of the patient blood oxygen concentration.

[0183] In some embodiments, the controller is configured to compare the estimated maximum future value of the patient blood oxygen concentration to the upper target blood oxygen concentration and generate the alarm output if the estimated maximum future value of the patient blood oxygen concentration is less than the upper target blood oxygen concentration.

[0184] In some embodiments, the alarm parameter or alarm output is based on a magnitude of a difference between the estimated maximum future value of the patient blood oxygen concentration and the upper target blood oxygen concentration.

[0185] In some embodiments, the controller is configured to compare the estimated minimum future value of the patient blood oxygen concentration to a lower target blood oxygen concentration, and to generate an alarm output if the estimated minimum future value of the patient blood oxygen concentration is less than the lower target blood oxygen concentration.

[0186] In some embodiments, the alarm parameter or alarm parameter of the alarm output is based on a magnitude of a difference between the estimated minimum future value of the patient blood oxygen concentration and the lower target blood oxygen concentration.

[0187] In some embodiments, the alarm parameter is an alarm time or an alarm intensity.

[0188] In some embodiments, the alarm output and / or related data is provided to a display.

[0189] In some embodiments, the alarm output is configured to present a message on the display.

[0190] In some embodiments, the alarm output is configured to produce a sound or provide an indication.

[0191] In some embodiments, the sensor or at least one sensor is in electronic communication with the controller.

[0192] In some embodiments, the at least one sensor is a pulse oximeter or an arterial oxygen sensor.

[0193] In some embodiments, the respiratory assistance device further comprises a gas composition sensor.

[0194] In some embodiments, the gas composition sensor is in electronic communication with the controller.

[0195] In some embodiments, the gas composition sensor is an oxygen concentration sensor configured to measure an oxygen concentration of the respiratory gas.

[0196] In some embodiments, the at least one gas composition sensor provides a signal indicative of an initial oxygen concentration of the respiratory gas.

[0197] In some embodiments, the controller is configured to receive an oxygen concentration signal from the oxygen concentration sensor indicative of an oxygen concentration of the respiratory gas.

[0198] In some embodiments, the controller is configured to control the oxygen concentration of the respiratory gas based on the oxygen concentration signal from the oxygen concentration sensor.

[0199] In some embodiments, the controller comprises one or more processors, wherein the processors are configured with computer readable instructions.

[0200] In some embodiments, the controller comprises at least one memory element, wherein the memory element is configured to store the computer readable instructions.

[0201] In some embodiments, the memory element is non-transitory.

[0202] In some embodiments, the flow generator is or comprises a blower module, wherein the blower module comprises at least one blower configured to generate the gas flow.

[0203] In some embodiments, the breathing assistance device comprises at least one display configured to display an alarm output.

[0204] In some embodiments, the display comprises at least one screen.

[0205] In some embodiments, the breathing assistance device comprises at least one sound producing device configured to output an audible sound.

[0206] In another system comprising any of the above aspects, a breathing assistance device, a conduit and a user interface.

[0207] In another aspect, there is provided a method of estimating a future value of a patient's blood oxygen concentration, the method comprising:

[0208] providing breathing gas having an initial target oxygen concentration to the patient,

[0209] measuring the patient's blood oxygen concentration,

[0210] providing breathing gas having a target oxygen concentration to the patient,

[0211] calculating a future value of the patient's blood oxygen concentration based on the patient's blood oxygen concentration and a difference between the initial target oxygen concentration and the target oxygen concentration.

[0212] In another aspect, there is provided a method of estimating a maximum future value of a patient's blood oxygen concentration for a target oxygen concentration range, the method comprising:

[0213] measuring the patient's blood oxygen concentration,

[0214] providing breathing gas having an oxygen concentration to the patient,

[0215] calculating a maximum future value of the patient's blood oxygen concentration based on the patient's blood oxygen concentration and a difference between an upper limit target oxygen concentration of the target oxygen concentration range and the oxygen concentration of the breathing gas.

[0216] In another aspect, there is provided a method of estimating a minimum future value of a patient's blood oxygen concentration for a target oxygen concentration range, the method comprising:

[0217] measuring a patient's blood oxygen concentration,

[0218] providing the patient with breathing gas having an oxygen concentration,

[0219] calculating a minimum future value of the patient's blood oxygen concentration based on the patient's blood oxygen concentration, and a difference between a lower target oxygen concentration of the target oxygen concentration range and the oxygen concentration of the breathing gas.

[0220] In another aspect, there is provided a method of estimating a future value of a patient's blood oxygen concentration, the method comprising:

[0221] providing the patient with breathing gas,

[0222] during an operation in which the device stores breathing gas oxygen concentration data, wherein the stored breathing gas oxygen concentration data comprises one or more oxygen concentrations of the breathing gas, each oxygen concentration of the breathing gas having an associated time stamp,

[0223] measuring a patient's blood oxygen concentration,

[0224] calculating an estimated future value of the patient's blood oxygen concentration based on:

[0225] the stored breathing gas oxygen concentration data, wherein the oxygen concentrations of the breathing gas are weighted based on the associated time stamps, and

[0226] the measurement indicative of the patient's blood oxygen concentration.

[0227] In another aspect, there is provided a method of estimating an estimated maximum future value of a patient's blood oxygen concentration, the method comprising:

[0228] providing the patient with breathing gas,

[0229] during an operation in which the device stores breathing gas oxygen concentration data, wherein the stored breathing gas oxygen concentration data comprises one or more oxygen concentrations of the breathing gas, each oxygen concentration of the breathing gas having an associated time stamp,

[0230] measuring a patient's blood oxygen concentration,

[0231] calculating an estimated maximum future value of the patient's blood oxygen concentration based on:

[0232] the stored breathing gas oxygen concentration data, wherein the oxygen concentrations of the breathing gas are weighted based on the associated time stamps, and

[0233] the measurement indicative of the patient's blood oxygen concentration,

[0234] a difference between the current oxygen concentration of the breathing gases and an upper target oxygen concentration.

[0235] In another aspect, there is provided a method of estimating a minimum future value of an estimate of a patient's blood oxygen concentration, the method comprising:

[0236] providing breathing gases to the patient,

[0237] during an operation in which the apparatus stores breathing gas oxygen concentration data, wherein the stored breathing gas oxygen concentration data comprises one or more oxygen concentrations of the breathing gases, each oxygen concentration of the breathing gases having an associated time stamp,

[0238] measuring a patient's blood oxygen concentration,

[0239] calculating a minimum future value of an estimate of the patient's blood oxygen concentration based on:

[0240] the stored breathing gas oxygen concentration data, wherein the oxygen concentrations of the breathing gases are weighted based on the associated time stamps, and

[0241] the measurement indicative of the patient's blood oxygen concentration,

[0242] a difference between the current oxygen concentration of the breathing gases of the current estimation phase and a lower target oxygen concentration.

[0243] In another aspect, there is provided a method of estimating a future value of a patient's blood oxygen concentration, the method comprising:

[0244] providing breathing gases to the patient,

[0245] maintaining a running total of changes in oxygen concentration of the breathing gases,

[0246] performing an estimate update phase, the estimate update phase comprising:

[0247] applying a decay function to the running total of changes in oxygen concentration of the breathing gases,

[0248] calculating a difference between the oxygen concentration of the breathing gases at the current estimate update phase and the breathing gases at the previous estimate update phase,

[0249] adding the difference to the running total of changes in oxygen concentration of the breathing gases.

[0250] In some embodiments, the controller is configured to calculate a future value of an estimate of a patient's blood oxygen concentration based on:

[0251] The sum of the changes in oxygen concentration of these respiratory gases, and

[0252] This measurement indicates the patient's blood oxygen concentration.

[0253] In some embodiments, the controller is configured to calculate the estimated maximum future value of the patient's blood oxygen concentration based on the following:

[0254] The sum of the changes in oxygen concentration of these respiratory gases, and

[0255] This measurement result indicates the patient's blood oxygen concentration.

[0256] The difference between the oxygen concentration of these respiratory gases in the current estimation phase and the upper limit target oxygen concentration.

[0257] In some embodiments, the controller is configured to calculate the minimum future value of the patient's blood oxygen concentration based on the following:

[0258] The sum of the changes in oxygen concentration of these respiratory gases, and

[0259] This measurement result indicates the patient's blood oxygen concentration.

[0260] The difference between the oxygen concentration of these respiratory gases in the current estimation phase and the lower limit target oxygen concentration.

[0261] On the other hand, a system including a respiratory assist device and an assistive device is provided, wherein an estimated maximum future value, and / or an estimated minimum future value, and / or an estimated future value are calculated on the assistive device.

[0262] On the other hand, a system including a respiratory assist device and an assistive device is provided, wherein the controller is at least partially located on the assistive device.

[0263] In some embodiments, the respiratory device provides sensor outputs and / or stored data to the assistive device.

[0264] In some embodiments, the alarm output or alarm output may be provided on the respiratory assist device.

[0265] In some embodiments, the alarm output or alarm output may be provided on an auxiliary device.

[0266] On the other hand, a respiratory assist device is provided for providing the method of any of the above aspects.

[0267] On the other hand, the use of a respiratory assist device is provided, which includes methods for providing any of the above aspects.

[0268] In another aspect, there is provided a use of a respiratory assistance device or a flow therapy device of any one of the above aspects, wherein the respiratory assistance device is the device of any one of the claims in any one of the above aspects.

[0269] Reference to a numerical range, for example 1 to 10, disclosed herein is intended to incorporate by reference all rational numbers within that range (for example 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and any range of rational numbers within that range (for example 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).

[0270] Broadly speaking, the embodiments described herein can also relate to parts, elements and features where shown in or described with respect to any figure, and any combination of two or more of said parts, elements or features, and where not explicitly otherwise stated each part, element or feature can be associated with all embodiments described herein.

[0271] In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge was at the priority date, commonly owned prior art, or part of the common general knowledge in the art.

[0272] The term "comprising", used in this specification, refers to "at least the parts of". When interpreting statements in this specification that include the term "comprising", the feature or features (the term "comprising" is written in front of the feature or features in each statement) are indicated as being amongst the possible parts but other parts can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

[0273] These and other features and aspects will now be described in detail with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0274] The application will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0275] FIG. 1A A flow therapy device is shown in diagrammatic form.

[0276] FIG. 1B A sensing circuit board is shown, the sensing circuit board including a flow sensor that can be used in a flow therapy device.

[0277] FIGS. 1C-DSchematic diagrams showing various ultrasonic transducer configurations for sensor assemblies using a cross-flow beam.

[0278] FIGS. 1E-F Schematic diagrams showing various ultrasonic transducer configurations for sensor assemblies using a cross-flow beam.

[0279] FIG. 2A , FIG. 2B and FIG. 3 Graphs showing operation of a respiratory device.

[0280] FIGS. 4A-D Process for estimating future values of patient blood oxygen.

[0281] FIG. 5A and FIG. 5B Alarm conditions for a respiratory device.

[0282] FIG. 6 Process for estimating maximum or minimum future values of patient blood oxygen.

[0283] FIG. 7 Graphs showing operation of a respiratory device.

[0284] FIG. 8A and FIG. 8B Graphs showing operation of a respiratory device.

[0285] FIG. 9A and FIG. 9B Process for estimating maximum or minimum future values of patient blood oxygen.

[0286] FIG. 10 Graphs showing operation of a respiratory device.

[0287] FIG. 10A Process for estimating patient oxygen efficiency.

[0288] FIG. 11 is a first bottom side perspective view of a main housing of a flow therapy apparatus showing a recess within the housing for a motor and / or sensor module subassembly.

[0289] FIG. 12 is a second bottom side perspective view of a main housing of a flow therapy apparatus showing a recess for a motor and / or sensor module subassembly.

[0290] FIG. 13 is a perspective view of a motor and / or sensor subassembly at a bottom side of a main housing of a flow therapy apparatus, and a fixed elbow.

[0291] FIG. 14is an exploded perspective view of components of the motor and / or sensor subassembly, with the gas flow path through the subassembly shown schematically by arrows.

[0292] FIG. 15 is a bottom side view of the cover piece and sensing PCB of the motor and / or sensor subassembly, showing the location of the sensors.

[0293] FIG. 16 is a rear perspective view of the flow therapy apparatus, cut away adjacent to the rear edge of the flow therapy apparatus, showing the arrangement of this portion of the recess provided in the main housing for receiving the motor and / or sensor subassembly.

[0294] FIG. 17A is a front left perspective view of the flow therapy apparatus.

[0295] FIG. 17B is a front left perspective view of the flow therapy apparatus.

[0296] FIG. 18 is a front left partial perspective cutaway view showing the valve module and filter module.

[0297] FIG. 19 is a schematic gas flow path diagram for the filter module and valve module, with solid arrows indicating the flow of oxygen (or another gas) and dashed arrows indicating the flow of ambient air.

[0298] FIG. 20 is a cross-sectional view showing the gas flow path through the filter module and valve module.

[0299] FIG. 21 is a rear top down perspective view of the first configuration valve module.

[0300] FIG. 22 is a rear top down perspective view showing the gas flow path through the first configuration valve module, with solid arrows indicating the flow of oxygen (or another gas) and dashed arrows indicating the flow of ambient air.

[0301] FIG. 23 is a cross-sectional view of the first configuration valve module.

[0302] FIG. 24 is a cross-sectional view showing the coupling of the valve and valve manifold of the first configuration valve module, and the gas flow path through the valve and valve manifold.

[0303] FIG. 25 is a schematic view of a breathing assistance apparatus and an auxiliary device. DETAILED DESCRIPTION

[0304] Patients with various health conditions and diseases can benefit from respiratory therapy. In at least one form, respiratory therapy can be oxygen therapy. For example, patients with chronic obstructive pulmonary disease (COPD), pneumonia, asthma, bronchopulmonary dysplasia, heart failure, cystic fibrosis, sleep apnea, lung disease, respiratory trauma, acute respiratory distress, and / or other conditions or diseases can benefit from respiratory therapy. Similarly, patients receiving preoperative and postoperative oxygen can also benefit from respiratory therapy. One common method of treating such issues is to supply the patient with a breathing gas that includes supplemental oxygen. In at least one configuration, a controlled concentration of supplemental oxygen can be supplied to the breathing gas. This supplemental oxygen helps to prevent the patient’s blood oxygen concentration (e.g., the blood oxygen saturation (Sp02)) from falling too low (e.g., below about 90%).

[0305] However, when providing respiratory therapy to a patient, such as by providing supplemental oxygen, changes in the patient’s blood oxygen concentration can lag behind changes in the provided oxygen concentration. That is, any change in the blood oxygen concentration can take a long time to occur from when the provided oxygen concentration changes. In other words, when providing respiratory therapy, such as supplemental oxygen therapy, to a patient, there can be a significant delay between a change in the provided oxygen concentration and the eventual change in the patient’s blood oxygen concentration. As a result, it can be difficult for a user to determine whether a change in the provided oxygen concentration will meet a desired therapy goal in terms of the patient’s blood oxygen concentration until a significant amount of time has passed. During this time, the patient can not be receiving adequate respiratory therapy.

[0306] Accordingly, a respiratory therapy device 10 can be provided that estimates the effect of a change in the oxygen concentration of a breathing gas on a patient’s blood oxygen concentration.

[0307] One benefit is that a user can quickly see the effect of a change in the oxygen concentration of a breathing gas on a patient’s blood oxygen concentration and determine whether this meets their therapy goal (e.g., a desired blood oxygen concentration).

[0308] Another benefit is that the respiratory therapy device 10 can alert based on an estimated future value of the patient’s blood oxygen concentration. For example, the respiratory therapy device 10 can alert when a change in the provided oxygen concentration of a breathing gas is estimated to not provide a desired change in the patient’s blood oxygen concentration.

[0309] When a user (typically a clinician, nurse, doctor, or other health practitioner) sets a target blood oxygen concentration, they can also set a target oxygen concentration range for the breathing gas. The respiratory therapy device 10 will then attempt to control the patient’s blood oxygen concentration by changing the provided oxygen concentration of the breathing gas while ensuring that the oxygen concentration of the breathing gas is within the target oxygen concentration range.

[0310] However, in some cases, the respiratory therapy device 10 will not achieve the target blood oxygen concentration when providing respiratory gases having a composition within the target oxygen concentration range. Again, in such cases, the patient can not be receiving adequate therapy.

[0311] Additionally, as noted above, changes in the patient's blood oxygen concentration can lag changes in the oxygen concentration provided. Thus, it can take some time for the user to realize that the patient is not receiving adequate therapy.

[0312] Accordingly, a respiratory therapy device 10 can be provided that estimates a maximum or minimum future blood oxygen concentration of the patient corresponding to the target oxygen range.

[0313] It will be appreciated that the terms "respiratory assistance device", "respiratory therapy device" and "flow therapy device" can be used interchangeably.

[0314] The device can then generate an alert output to notify the user that the device will not achieve the target blood oxygen concentration when providing respiratory gases having a composition within the target oxygen concentration range. The user can then review the patient and optionally modify the target oxygen concentration range.

[0315] In some embodiments, if the device detects that the target blood oxygen concentration cannot be achieved within the target oxygen concentration range, the device can determine an updated target oxygen concentration range.

[0316] The estimation of the maximum or minimum future blood oxygen concentration can provide an early indication to the user that the patient is not receiving adequate therapy.

[0317] The blood oxygen concentration can be peripheral capillary oxygen saturation (Sp02) or partial pressure of oxygen (Pa02).

[0318] The oxygen concentration of the respiratory gases can be the fraction of inspired oxygen (Fi02) (e.g. the percentage of oxygen of the respiratory gases inhaled by the patient), or the fraction of delivered oxygen (Fd02) (e.g. the percentage of oxygen of the respiratory gases delivered to the patient).

[0319] Physiologically, the oxygen provided to the patient (e.g. as the fraction of inspired oxygen (Fi02)) will be transferred into the patient's blood via the lungs (e.g. as the partial pressure of oxygen (Pa02))

[0320] The oxygen in the patient's blood (e.g. as the partial pressure of oxygen (Pa02)) can be converted to the peripheral capillary oxygen saturation (Sp02) using a hemoglobin saturation function.

[0321] In FIG. 1AA respiratory therapy device 10 is shown in FIG. 1. The respiratory therapy device 10 can include a main housing 100 that houses a flow generator 11 (e.g., a blower) in the form of a motor / impeller arrangement, an optional humidifier 12, a controller 13, and a user interface 14 (including, e.g., a display and input devices such as buttons, a touch screen, etc.). The controller 13 can be configured or programmed to control operation of the respiratory therapy device 10. For example, the controller 13 can control components of the respiratory therapy device 10 including, but not limited to: operating the flow generator 11 to generate a flow of gas (a flow of each gas) for delivery to a patient; operating the humidifier 12 (if present) to humidify and / or heat the generated flow of gas; controlling the flow of oxygen into the flow generator blower; receiving user input from the user interface 14 to reconfigure and / or user-defined operation of the respiratory therapy device 10; and outputting information to the user (e.g., on the display).

[0322] For these purposes, the controller 13 includes one or more computer processors 13a and associated non-transitory memory or storage medium that stores processor-executable instructions or code. When executed by the one or more processors, these instructions cause the respiratory therapy device to implement the steps and processes described herein.

[0323] The user can be a patient, a healthcare professional (e.g., a clinician), or any other person interested in using the device. As used herein, a “flow of gas” can refer to any flow of gas that can be used in a respiratory assist or breathing apparatus, such as a flow of ambient air, a flow containing substantially 100% oxygen, a flow containing some combination of ambient air and oxygen, and so on.

[0324] A patient breathing conduit 16 is coupled at one end to a gas flow outlet 21 in the housing 100 of the respiratory therapy device 10. The patient breathing conduit 16 is coupled at the other end to a patient interface 17, such as a non-sealing nasal cannula having a manifold 19 and nasal prongs 18. Additionally or alternatively, the patient breathing conduit 16 can be coupled to a face mask, a nasal mask, a nasal pillows mask, an endotracheal tube, a tracheostomy interface, etc. The flow of gas generated by the flow therapy device 10 can be humidified and delivered to the patient via the patient breathing conduit 16 through the patient interface 17. The patient breathing conduit 16 can have a heating element 16a to heat the flow of gas passing therethrough to the patient. The heating element 16a can be under the control of the controller 13. In at least one configuration, the heating element 16a is a heating wire 16a. The patient breathing conduit 16 and / or the patient interface 17 can be considered part of the respiratory therapy device 10, or alternatively peripheral to the respiratory therapy device. The respiratory therapy system 1 can include the respiratory therapy device 10, the patient breathing conduit 16, and the patient interface 17, which together can form a respiratory therapy system.

[0325] The controller 13 can control the flow generator 11 to generate a flow of gas having a desired flow rate. The controller 13 can also control the supplemental oxygen inlet to allow delivery of supplemental oxygen. The humidifier 12, if present, can humidify the flow of gas and / or heat the flow of gas to a suitable level, etc. The controller 13 can be configured to control the humidifier 12. The flow of gas is directed out to the patient through the patient breathing conduit 16 and the patient interface 17. The controller 13 can also control the humidifier heating element 16b in the humidifier 12 and / or the heating element 16a in the patient conduit 16 to heat the gas to a desired temperature to achieve a desired level of therapy and / or comfort level for the patient. The controller 13 can be programmed with a suitable target temperature for the flow of gas or can determine a suitable target temperature for the flow of gas.

[0326] The oxygen inlet port 28 can include a valve through which pressurized gas can enter the respiratory therapy device 10. The valve can control the flow of oxygen into the respiratory therapy device 10. The valve can be any type of valve, including a proportional valve or a two-position valve. The source of oxygen can be an oxygen tank or a hospital oxygen supply. Medical grade oxygen is typically between 95% and 100% pure. Lower purity oxygen sources can also be used. Examples of valve modules and filters are disclosed in U.S. Provisional Application No. 62 / 409,543, filed October 18, 2016, entitled “Valve Modules and Filters,” and U.S. Provisional Application No. 62 / 488,841, filed April 23, 2017, entitled “Valve Modules and Filters,” which are incorporated by reference herein in their entireties. Valve modules and filters are discussed in further detail below with respect to FIGS. 7-15

[0327] The flow therapy device 10 can measure and control the oxygen content of the gas delivered to the patient, and thus the oxygen content of the gas inhaled by the patient. In at least one implementation of high flow therapy, the high flow of delivered gas meets or exceeds the peak inspiratory demand of the patient. This means that the volume of gas delivered to the patient by the device during inhalation meets or exceeds the volume of gas inhaled by the patient during inhalation. Thus, high flow therapy can help prevent entrainment of ambient air as the patient inhales, and flushes out exhaled gases in the patient’s airways. As long as the flow of delivered gas meets or exceeds the peak inspiratory demand of the patient, entrainment of ambient air is prevented, and the gas delivered by the device is substantially the same as the gas inhaled by the patient. As such, the oxygen concentration measured in the device can be equivalent to the delivered fraction of inspired oxygen (Fd02), and can be substantially the same as the oxygen concentration breathed by the patient, the fraction of inspired oxygen (Fi02), and thus such terms can be considered equivalent. ​

[0328] Operational sensors 3a, 3b, 3c, such as flow sensors, temperature sensors, humidity sensors, and / or pressure sensors, can be placed in various locations in the flow therapy device 10. Additional sensors (e.g., sensors 20, 25) can be placed in various locations on the patient conduit 16 and / or the patient interface 17 (e.g., a temperature sensor 29 can be present at or near the end of the inspiratory tube). These sensors can be monitored by the controller 13. This can assist the controller 13 in operating the flow therapy device 10 in a manner that provides suitable therapy. In some configurations, providing suitable therapy includes meeting the peak inspiratory demand of the patient. The respiratory therapy device 10 can have a transmitter, receiver, and / or transceiver 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, the humidifier 12, and the heating element 16a, the humidifier heating element 16b, or accessories or peripherals associated with the flow therapy device 10. Additionally or alternatively, the transmitter, receiver, and / or transceiver 15 can deliver data to a remote server, or enable remote control of the respiratory therapy device 10 or respiratory therapy system 1.

[0329] After the oxygen and ambient air have been mixed, the oxygen can be measured by placing one or more gas composition sensors, such as an ultrasonic transducer system. This measurement can be made within the respiratory therapy device 10, the patient breathing conduit 16, the patient interface 17, or at any other suitable location.

[0330] The oxygen concentration can also be measured by using flow sensors on at least two of the ambient air inlet conduit, the oxygen inlet conduit, and the patient breathing conduit to determine the flow of at least two gases. By determining the flow of two inlet gases or one inlet gas and one total flow along with an assumed or measured oxygen concentration of the inlet gases (ambient air is about 20.9% and oxygen is about 100%), the oxygen concentration of the final gas composition can be calculated. Alternatively, flow sensors can be placed at all three of the ambient air inlet conduit, the oxygen inlet conduit, and the final delivery conduit to allow for redundancy and to test that each sensor is working correctly by checking for consistency of readings. Other methods of measuring the oxygen concentration delivered by the flow therapy device 10 can also be used.

[0331] The flow therapy apparatus 10 can include a patient sensor 26, such as a pulse oximeter or a patient monitoring system, to measure one or more physiological parameters of the patient, such as the patient's blood oxygen concentration (e.g. the patient's blood oxygen saturation (Sp02)), heart rate, respiratory rate, perfusion index, and to provide a measure of signal quality. The sensor 26 can communicate with the controller 13 by a wired connection or by communication via a wireless transmitter on the sensor 26. The sensor 26 can be a disposable adhesive sensor designed to be connected to the patient's finger. The sensor 26 can be a non-disposable sensor. Sensors designed for different age groups and to be connected to different locations on the patient are available which can be used with the flow therapy system 1. The pulse oximeter can be attached to the patient, typically at their finger, but other locations such as the earlobe are an option. The pulse oximeter can be connected to a processor in the respiratory therapy apparatus 10 and will constantly provide a signal indicative of the patient's blood oxygen saturation. The patient sensor 26 can be a hot-pluggable device which can be attached or interchanged during operation of the flow therapy apparatus 10. For example, the patient sensor 26 can be connected to the flow therapy apparatus 10 using a USB interface or using a wireless communication protocol such as Bluetooth®. When the patient sensor 26 is disconnected during operation, the flow therapy apparatus 10 can continue to operate in its previous operating state for a defined period of time. After the defined period of time, the flow therapy apparatus 10 can trigger an alarm, transition from an automatic mode to a manual mode, and / or exit the control mode (e.g. the automatic mode or the manual mode) altogether. The patient sensor 26 can be a bedside monitoring system or other patient monitoring system which communicates with the flow therapy apparatus 10 by a physical or wireless interface. ) When the patient sensor 26 is disconnected during operation, the flow therapy apparatus 10 can continue to operate in its previous operating state for a defined period of time. After the defined period of time, the flow therapy apparatus 10 can trigger an alarm, transition from an automatic mode to a manual mode, and / or exit the control mode (e.g. the automatic mode or the manual mode) altogether. The patient sensor 26 can be a bedside monitoring system or other patient monitoring system which communicates with the flow therapy apparatus 10 by a physical or wireless interface.

[0332] The flow therapy apparatus 10 can comprise or be in the form of a high flow therapy apparatus. As used herein, "high flow" therapy refers to the administration of gas to a patient's airways at a relatively high flow rate that meets or exceeds the patient's peak inspiratory demand. The flow rate used to achieve "high flow" can be any of the flow rates listed below. For example, in some configurations, for an adult patient, "high flow therapy" can refer to the delivery of gas to the patient at a flow rate of greater than or equal to about 10 liters per minute (10 LPM), such as between about 10 LPM and about 100 LPM, or between about 15 LPM and about 95 LPM, or between about 20 LPM and about 90 LPM, or between about 25 LPM and 75 LPM, or between about 25 LPM and about 85 LPM, or between about 30 LPM and about 80 LPM, or between about 35 LPM and about 75 LPM, or between about 40 LPM and about 70 LPM, or between about 45 LPM and about 65 LPM, or between about 50 LPM and about 60 LPM. In some configurations, for a neonatal, infant, or child patient, "high flow therapy" can refer to the delivery of gas to the patient at a flow rate of greater than 1 LPM, such as between about 1 LPM and about 25 LPM, or between about 2 LPM and about 25 LPM, or between about 2 LPM and about 5 LPM, or between about 5 LPM and about 25 LPM, or between about 5 LPM and about 10 LPM, or between about 10 LPM and about 25 LPM, or between about 10 LPM and about 20 LPM, or between about 10 LPM and 15 LPM, or between about 20 LPM and 25 LPM. A high flow therapy apparatus for an adult patient, neonatal, infant, or child patient can deliver gas to the patient at a flow rate of between about 1 LPM and about 100 LPM, or at a flow rate in any of the subranges listed above. The flow therapy apparatus 10 can deliver oxygen (e.g., Fd02) at any concentration up to 100% at any flow rate between about 1 LPM and about 100 LPM. In some configurations, any of these flow rates can be combined with an oxygen concentration (Fd02) of about 20% to 30%, 21% to 30%, 21% to 40%, 30% to 40%, 40% to 50%, 50% to 60%, 60% to 70%, 70% to 80%, 80% to 90%, and 90% to 100%. In some combinations, the flow rate can be between about 25 LPM and 75 LPM and combined with an oxygen concentration (Fd02) of about 20% to 30%, 21% to 30%, 21% to 40%, 30% to 40%, 40% to 50%, 50% to 60%, 60% to 70%, 70% to 80%, 80% to 90%, and 90% to 100%. In some configurations, the flow therapy apparatus 10 can include safety thresholds when operating in a manual mode that prevent the patient from delivering too much oxygen to the patient.

[0333] High flow therapy can be administered to a patient's nares and / or orally, or via a tracheostomy interface. High flow therapy can deliver gas to a patient at a flow rate equal to or exceeding the peak inspiratory flow requirements of the intended patient. High flow therapy can create a washout effect in the nasopharynx such that the anatomic dead space of the upper airways is washed out by the incoming high flow of gas. This can result in a fresh gas reservoir available for each breath while minimizing rebreathing of nitrogen and carbon dioxide. Additionally, meeting inspiratory demand and washing out the airways is important when attempting to control the Fd02 of a patient. High flow therapy can be delivered with a non-sealing patient interface, such as a nasal cannula. The patient interface 17 can be configured to deliver breathing gas to the nares of a patient at a flow rate that exceeds the peak inspiratory flow requirements of the intended patient.

[0334] As used herein, the term "non-sealing patient interface" can refer to an interface that provides a pneumatic connection between the patient's airways and a flow of gas from a flow generator 11 that does not completely occlude the patient's airways. The non-sealing pneumatic connection can include less than about 95% occlusion of the patient's airways. The non-sealing pneumatic connection can include less than about 90% occlusion of the patient's airways. The non-sealing pneumatic connection can include between about 40% and about 80% occlusion of the patient's airways. The airways can include one or more of the patient's nares or mouth. For a nasal cannula, the airways are through the nares.

[0335] The flow generator 11 can be or include a blower module. The blower module can include at least one blower 11 configured to generate the flow of gas.

[0336] The flow generator 11 can include an ambient air inlet port 27 to entrain ambient room air into the blower. The high flow therapy apparatus 10 can also include an oxygen inlet port 28 to a valve through which pressurized gas can enter the flow generator 11. The valve can control the flow of oxygen into the flow generator 11. The valve can be any type of valve, including a proportional valve or a two-position valve.

[0337] The blower 11 can operate at a motor speed greater than about 1,000 RPM and less than about 30,000 RPM, greater than about 2,000 RPM and less than about 21,000 RPM, or between any of the foregoing values. Operation of the blower 11 can mix the gases entering the blower 11 through the inlet ports, such as the ambient air inlet port 27 and / or the oxygen inlet port 28. Using the blower 11 as a mixer can reduce the pressure drop that would otherwise occur in a system with a separate mixer, such as a static mixer including baffles, because mixing requires energy.

[0338] The respiratory assistance apparatus can further comprise a gas composition sensor. The gas composition sensor can be a sensor described below (e.g. an ultrasonic transducer configuration).

[0339] The gas composition sensor can be connected to the controller.

[0340] The gas composition sensor can be located at any point in the flow path.

[0341] The gas composition sensor can be an oxygen concentration sensor configured to measure an oxygen concentration of the respiratory gas.

[0342] The controller can be configured to receive an oxygen concentration signal from the oxygen concentration sensor indicative of the oxygen concentration of the respiratory gas.

[0343] The gas composition sensor can be configured to provide a gas composition sensor output to the controller. Optionally, the gas composition sensor output can be a signal indicative of a gas composition (e.g. oxygen concentration) of the respiratory gas.

[0344] The gas composition sensor can be in electronic communication with the controller.

[0345] The controller can be configured to control the oxygen concentration of the respiratory gas based on the oxygen concentration signal from the oxygen concentration sensor.

[0346] The respiratory assistance apparatus can further comprise a blood oxygen concentration sensor.

[0347] The blood oxygen concentration sensor can provide a signal to the controller.

[0348] The blood oxygen concentration sensor can be a pulse oximeter or an arterial oxygen sensor.

[0349] The blood oxygen concentration sensor can be in electronic communication with the controller.

[0350] The controller 13 can comprise one or more processors. The processor(s) can be configured with computer readable instructions.

[0351] The controller 13 can comprise at least one memory element. The memory element can be configured to store the computer readable instructions.

[0352] The memory element can be non-transitory.

[0353] The respiratory assistance apparatus can comprise at least one display module configured to display an alarm output.

[0354] In some embodiments, information relating to the estimated future value can be displayed. For example, an estimated minimum future value of the patient’s blood oxygen and / or an estimated minimum future value of the patient’s blood oxygen concentration, and / or an estimated future value.

[0355] The breathing assistance apparatus can comprise at least one sound module configured to emit a sound alert.

[0356] The display module can comprise at least one display (e.g. a liquid crystal display (LCD) or a light emitting diode (LED) display, although it will be appreciated that any display technology can be used).

[0357] The display module can be configured to receive input to the system (e.g. as a touch screen).

[0358] Additional reference FIG. 1B is shown a sensing circuit board 2200 that can be implemented in the flow therapy apparatus 10. The sensing circuit board 2200 can be positioned in a sensor chamber such that the sensing circuit board 2200 is at least partially immersed in a flow of gas. The flow of gas can exit the blower 11 through a conduit and into a flow path in the sensor chamber. At least some of the sensors on the sensing circuit board 2200 can be positioned within the flow of gas to measure a property of the gas within the flow. After passing through the flow path in the sensor chamber, the gas can exit to the humidifier 12 described above.

[0359] The sensing circuit board 2200 can be a printed sensing circuit board (PCB). Alternatively, the circuit on the board 2200 can be constructed with wires connecting electronic components, rather than the circuit being printed on a circuit board. At least a portion of the sensing circuit board 2200 can be mounted outside of the flow of gas. The flow of gas can be generated by the flow generator 11 described above. The sensing circuit board 2200 can include an ultrasonic transducer 2204. The sensing circuit board 2200 can include one or more of a thermistor 2205. The thermistor 2205 can be configured to measure a temperature of the flow of gas. The sensing circuit board 2200 can include a thermistor flow sensor 2206. The sensing circuit board 2200 can include other types of sensors, such as a humidity sensor (including a humidity sensor only to be used with a separate temperature sensor, as well as a combined humidity sensor and temperature sensor), a sensor to measure atmospheric pressure, a sensor to measure differential pressure, and / or a sensor to measure gage pressure. The thermistor flow sensor 2206 can include a hot wire flow meter, such as a platinum wire and / or a thermistor (such as a negative temperature coefficient (NTC) thermistor, or a positive temperature coefficient (PTC) thermistor). Other non-limiting examples of heated temperature sensing elements include glass or epoxy encapsulated thermistors, or non-encapsulated thermistors. The thermistor flow sensor 2206 can be configured to measure a flow of gas by being supplied with a constant power, or to maintain a constant sensor temperature or a constant temperature difference between the sensor and the flow of gas.

[0360] The sensing circuit board 2200 can include a first portion 2201 and a second portion 2202. The first portion 2201 can be positioned within the flow path of the gas, while the second portion 2202 can be positioned outside of the flow path of the gas. The direction of the gas flow is indicated by arrow 2203. The direction of the gas flow can be straight, or curved as shown in FIG. 1B FIG. 1B

[0361] Positioning one or more of the thermistor 2205 and / or the thermistor flow sensor 2206 downstream of the combined blower and mixer can account for heat supplied to the gas flow from the blower. Also, immersing a temperature-based flow sensor in the flow path can improve the accuracy of the measurement, as a sensor immersed in the flow is more likely to be subjected to the same conditions (such as temperature) as the gas flow, and thus provide a better representation of the gas properties.

[0362] The sensing circuit board 2200 can include an ultrasonic transducer, transceiver, or sensor of the sensing circuit board to measure a gas property of the gas flow, such as a gas composition or concentration of one or more gases within the gas flow. As should be appreciated, any suitable transducer, transceiver, or sensor can be mounted to the sensing circuit board 2200. In such a configuration, the gas composition sensor is an ultrasonic transducer that employs ultrasonic or acoustic waves to determine gas concentrations. Various sensor configurations are described below with respect to FIGS. 1C-F

[0363] The ultrasonic transducer can determine the relative gas concentrations of two or more gases in the gas flow. The ultrasonic transducer can be configured to measure the fraction of oxygen in a bulk gas flow that is composed of atmospheric air augmented with supplemental oxygen, which is essentially a binary gas mixture of nitrogen (N2) and oxygen (O2). It will also be appreciated that the ultrasonic transducer can be configured to measure the gas concentrations of other augmenting gases (including nitrogen (N2) and carbon dioxide (CO2)) that have been blended with the atmospheric air in the gas flow. The ultrasonic sensor can determine the gas concentrations of the gases in the gas flow at a relatively high frequency. For example, the ultrasonic sensor can output measured FdO2 values at the maximum sampling rate of the sensor or at a frequency lower than the maximum sampling rate, such as between about 1 Hz and 200 Hz, between about 1 Hz and 100 Hz, between about 1 Hz and 50 Hz, and between about 1 Hz and 25 Hz.

[0364] In some configurations, the sensing circuit board 2200 includes a pair of ultrasonic transducers disposed on opposite sides of the sensing circuit board. Various alternative configurations of ultrasonic transducers can be used to sense properties of the gas flow by emitting and receiving ultrasonic beams or pulses.

[0365] ​​​The distance between the ultrasonic transducers 2204 on opposite ends of the sensing circuit board 2200 affects the measurement resolution. An increased distance between each of the ultrasonic transducers 2204 can reduce the proportional or fractional error because, in general, the length measured will have some amount of error, and if the length is increased, the proportion of error produced during the measurement is less than the proportion of error for a shorter length. Thus, the overall uncertainty of the measurement is reduced. The increase in distance can also improve the measurement resolution and accuracy because it allows the acoustic signal between the ultrasonic transducers 2204 a longer period of time. However, the increase in distance can result in a weaker signal.

[0366] The ultrasonic transducers 2204 can be positioned such that the space between the ultrasonic transducers 2204 at least partially coincides with the flow path. In some configurations, the ultrasonic transducers are positioned on opposite ends of the sensing circuit board. Because the entire face of the flow path is exposed to the acoustic path, the acoustic wave propagates through all of the gas in the flow path. The averaging of the wave can occur over the entire flow path rather than a section of the flow path. Averaging over a longer distance reduces the error and reduces the dependence on the air-oxygen mixture. The ultrasonic transducers can be configured to measure the gas properties from any angle relative to the flow path.

[0367] Instead of being positioned outside of the flow path or module, positioning the sensor in the flow path or module allows both transducers 2204 to operate within a smaller temperature range relative to each other or both to operate substantially at one temperature (i.e., the temperature of the gas flow). Because the transducers are sensitive to temperature, having them at a substantially uniform temperature improves the accuracy. Further, positioning the sensor along the flow path allows the measurement and calculation to account for the effects of gas velocity so that the effects of gas velocity can be removed from the sensor measurement results.

[0368] Reference FIGS. 1C-F Various configurations of ultrasonic transducers for a gas composition sensing system will be described for sensing the speed of sound through a gas flow by transmitting and receiving ultrasonic beams or pulses. Like reference numerals represent like parts.

[0369] Reference FIG. 1C, the transducer configuration 2300 provides an arrangement in which a pair of transducers 2302, 2304 are present that oppose one another from opposite sides of a sensing passage 2306, with the air flow path direction generally indicated by 2308. In this configuration, each of the transducers 2302, 2304 is driven as either a dedicated transmitter or receiver, such that an ultrasonic wave pulse 2310 is unidirectionally launched across the gas flow path from the transmitter to the receiver transducer. As shown, the pair of transducers are aligned with respect to the air flow path direction 2308 (i.e., not displaced upstream or downstream of one another), and are configured to launch cross-flow pulses substantially perpendicular to the gas flow path direction.

[0370] Referring to FIG. 1D , an alternative transducer configuration 2320 is shown in which a pair of transducers 2322, 2324 are disposed on opposite sides of the sensing passage opposite one another, but in which each transducer can operate as both a transmitter and receiver, i.e., the transducers are ultrasonic transmitters-receivers or transceivers. In this configuration, bidirectional ultrasonic wave pulses 2326 can be sent between the pair of transducers 2322, 2324. For example, the pulses can be sent back and forth between the transducers alternately or in any other sequence or pattern. Again, the pair of transducers are aligned with respect to the gas flow path direction, and are configured to launch cross-flow pulses substantially perpendicular to the gas flow path direction.

[0371] Referring to FIG. 1E , an alternative transducer configuration 2360 is shown in which a pair of transducers 2362, 2364 are from opposite ends of the sensing passage 2306 and oppose one another, with the gas flow path direction or axis generally indicated by 2308. In this configuration 2360, each of the transducers 2362, 2364 is driven as either a dedicated transmitter or receiver, such that a down-flow ultrasonic wave pulse 2366 is unidirectionally launched in a beam path between the transmitter and receiver that is substantially aligned or parallel with the gas flow path axis 2308 in the sensing passage 2306. In the illustrated embodiment, the transmitter is upstream of the receiver, but it should be understood that the reverse arrangement can be employed. With this configuration, a flow sensor is disposed in the sensing passage to provide a flow signal indicative of the flow of gas in the sensing passage. It should be understood that the speed of sound in the sensing passage can be derived or determined in a similar manner as the previously described embodiments, and the flow speed signal is utilized in signal processing to remove or compensate for the gas flow speed in the calculated speed of sound signal.

[0372] Referring to FIG. 1F , an alternative transducer configuration 2370 is shown in which FIG. 1EAs with the middle, a pair of transducers 2372, 2374 are provided from opposite ends of the sensing channel and opposite one another, but where each transducer can operate as both a transmitter and receiver (i.e. the transducer is an ultrasonic transmitter-receiver or transceiver). In this configuration, bidirectional downflow ultrasonic pulses 2376 can be sent between the pair of transducers 2372, 2374. For example, the pulses can be sent back and forth between the transducers alternately or in any other sequence or pattern. Again, the pair of transducers are aligned with the gas flow path axis 2308 and are configured to transmit cross-flow pulses in one or more beam paths that are substantially aligned or parallel with the gas flow path axis 2308 in the sensing channel 2306. With this configuration, there is no necessarily need to provide a separate flow sensor as the flow component of the speed of sound can be directly derived or determined from the processing of the transmitted and received acoustic pulses.

[0373] Some examples of flow therapy apparatus are disclosed in International Application No. PCT / NZ2016 / 050193 entitled “Flow Path Sensing for Flow Therapy Apparatus” filed on 2 December 2016 and International Application No. PCT / IB2016 / 053761 entitled “Breathing Assistance Apparatus” filed on 24 June 2016, which are incorporated by reference in their entirety herein. Further details of examples of configurations of flow therapy apparatus that can be used with aspects of the present disclosure are discussed below in relation to FIGS. 14-19

[0374] Again referring to FIG. 1A The controller 13 can be programmed or configured to implement a closed loop control system for controlling the operation of the flow therapy apparatus 10. The closed loop control system can be configured to ensure that the patient’s blood oxygen concentration (e.g. Sp02) reaches a target level and is maintained at or close to that level at all times.

[0375] An oxygen control system is described in International Application No. PCT / NZ2018 / 050137 entitled “Closed Loop Oxygen Control” filed on 5 October 2018, which is incorporated by reference in its entirety.

[0376] The controller 13 can be configured to control the patient’s blood oxygen concentration to a target blood oxygen concentration (or a target blood oxygen concentration range). The controller 13 can be configured to receive a signal indicative of the patient’s blood oxygen concentration and calculate a target oxygen concentration of the breathing gas to control the patient’s blood oxygen concentration to the target blood oxygen concentration (or target blood oxygen concentration range).​

[0377] The target oxygen concentration of the breathing gas can be controlled to be within a target oxygen concentration range of the breathing gas (to be described in more detail below).

[0378] The controller 13 can be configured to control the oxygen concentration of the breathing gas to a target oxygen concentration of the breathing gas. The controller 13 can be configured to receive a signal indicative of the oxygen concentration of the breathing gas and control the oxygen concentration of the breathing gas to a target oxygen concentration of the breathing gas.

[0379] The oxygen concentration of the breathing gas can be, for example, a measured oxygen concentration of the breathing gas, and / or an oxygen concentration of the delivered breathing gas, and / or an oxygen concentration of the provided breathing gas.

[0380] The controller 13 can receive input from the user that can be used by the controller 13 to perform a closed loop control system. The input(s) can include a target blood oxygen concentration of the patient. The target blood oxygen concentration can be a target Sp02 value. The target blood oxygen concentration can be a single value or a range of values. The value(s) can be pre-set, selected by the user, or determined based on the type of patient. The type of patient can refer to the current distress and / or information about the patient such as age, weight, height, gender, and other patient characteristics. Similarly, the target Sp02 can be two values, each selected in any of the ways described above. The two values would represent a range of acceptable values for the target blood oxygen concentration of the patient (to be described in more detail below). The controller can target a value within the range. The target blood oxygen concentration can be the middle value of the range, or any other value within the range, which can be pre-set or selected by the user. Alternatively, the range can be automatically set based on the target blood oxygen concentration. The controller can be configured to have one or more set responses when the blood oxygen concentration of the patient moves outside of the range. The responses can include sounding an alarm, changing to manual control of the Fd02, changing the Fd02 to a specific value, and / or other responses. The controller can have one or more ranges, where a different response or responses occur when the controller moves outside of each range.

[0381] The graphical user interface of the flow therapy apparatus 10 can be configured to prompt the user to input the type of patient, and the target blood oxygen concentration (or, for example, a target blood oxygen concentration range) will be determined based on what the user selects. Additionally, the user interface can include a customization option, where the user can define the limit values of the target oxygen concentration range of the breathing gas.

[0382] Typically, the patient's blood oxygen concentration (e.g., Sp02) will be controlled to be between about 80% and about 100%, or between about 80% and about 90%, or between about 88% and about 92%, or between about 90% and about 99%, or between about 92% and about 96%. The Sp02 can be controlled to be between any two suitable values from any two of the above ranges. The target Sp02 can be between about 80% and about 100%, or between about 80% and about 90%, or between about 88% and about 92%, or between about 90% and about 99%, or between about 92% and about 96%, or about 94%, or 94%, or about 90%, or 90%, or about 85%, or 85%. The target Sp02 can be any value between any two suitable values from any two of the above ranges. The target Sp02 can correspond to the middle value of a defined Sp02 range.

[0383] The input(s) received by the controller 13 can additionally or alternatively include a target oxygen concentration range. The target oxygen concentration range can be a target Fd02 or Fi02.

[0384] The target oxygen concentration range can be provided via the user interface 14.

[0385] As discussed above, the oxygen concentration of the breathing gas (e.g., Fd02) can be controlled to be within a target oxygen concentration range for the breathing gas. The target oxygen range can be an allowable range in which the Fd02 is controlled. As previously discussed, as long as the flow meets or exceeds the peak inspiratory demand of the patient, the oxygen concentration measured in the device (e.g., Fd02) will be substantially the same as the oxygen concentration breathed by the patient (Fi02), and thus such terms can be considered equivalent. Each limit of the target oxygen concentration range can be pre-set, selected by a user, or determined based on the type of patient. The type of patient can refer to the current distress and / or information about the patient such as age, weight, height, gender, and / or other patient characteristics. Alternatively, a single value for Fd02 can be selected. The target oxygen concentration range can be determined based at least in part on this value. For example, the target oxygen concentration range can be a set amount above and below the selected Fd02. The selected Fd02 can be used as a starting point for the controller 13. If the controller 13 attempts to move the Fd02 outside of the target oxygen concentration range, the respiratory therapy device 10 can have one or more responses. These responses can include sounding an alarm, preventing the Fd02 from moving outside of the range, switching to manual control of the Fd02, and / or switching to a specific Fd02. The respiratory therapy device 10 can have one or more target oxygen concentration ranges, where one or more different responses occur when the respiratory therapy device reaches the limit of each target oxygen concentration range.

[0386] The target oxygen concentration range of the respiratory gas can include an upper target oxygen concentration.

[0387] The target oxygen concentration range of the respiratory gas can include a lower target oxygen concentration.

[0388] It will be appreciated that in some cases, the upper target oxygen concentration or the lower target oxygen concentration can not be provided.

[0389] The oxygen concentration of the respiratory gas (e.g., Fd02) can be controlled between about 21% and about 100%, or between about 21% and about 90%, or between about 21% and about 80%, or between about 21% and about 70%, or between about 21% and about 60%, or between about 21% and about 50%, or between about 25% and about 45%. The Fd02 can be controlled between any two suitable values from any two ranges described. The Fd02 target can be between any two suitable values from any two ranges described. If a range is based on a single value, the upper and lower limits can be determined by adding / subtracting a fixed amount from the selected value. The amount added or subtracted can be about 1%, or about 5%, or 10%, or about 15%, or about 20%, or about 30%, or about 50%, or about 100%. The amount added / subtracted can vary relative to the selected value. For example, the upper limit can be 20% higher than the selected value, so for the range of control, a selected value of 50% Fd02 would have an upper limit of 60%. The percentage used for the range can be about 1%, or about 5%, or 10%, or about 15%, or about 20%, or about 30%, or about 50%, or about 100%. The method used to calculate the lower and upper limits will not necessarily need to be the same. If a single value is used, the value can be between about 21% and about 100%, or between about 25% and about 90%, or between about 25% and about 80%, or between about 25% and about 70%, or between about 25% and about 60%, or between about 25% and about 50%, or between about 25% and about 45%.

[0390] The graphical user interface 14 (GUI) can be configured to display the range of values between which the Fd02 and / or Sp02 is controlled. The range (e.g., the patient target blood oxygen range, or the target oxygen concentration range of the respiratory gas) can be displayed by having the two limit values set apart from each other on the GUI, with an indicator appearing within the respective range to graphically represent the location of the current value relative to the range limit values.

[0391] The GUI can display a graph of recent Fd02 and / or Sp02 data. The GUI can display the level of each parameter over the same or different graphs over a defined period of time, such as one or more hours. The length of time over which data is displayed can match the length of time over which data is currently available.

[0392] The displayed FdO2 data can be at least one of a target FdO2 or a measured FdO2. The SpO2 data can include a line indicating a target SpO2. Additionally or alternatively, the SpO2 and / or FdO2 data can include one or more lines or one or more shaded regions indicating their respective control limits.

[0393] The graph can be displayed on a default display. Alternatively, the graph can be hidden and only the current data values displayed. The graph can become available through interaction with the GUI, such as by selecting to view the graph for a defined parameter.

[0394] The closed loop control system can utilize two control loops. A first control loop can be implemented by a blood oxygen concentration (e.g., SpO2) controller. The blood oxygen concentration controller can determine a target oxygen concentration (e.g., FdO2) based in part on a target blood oxygen concentration and / or a measured blood oxygen concentration. As discussed above, the target blood oxygen concentration value can be a single value, or a range of acceptable values. The value(s) can be pre-set, selected by a user, or automatically determined based on patient characteristics.

[0395] The target blood oxygen concentration can be controlled within a target blood oxygen concentration range.

[0396] The target blood oxygen concentration range can include an upper target blood oxygen concentration and / or a lower target blood oxygen concentration.

[0397] The controller 13 can be configured to control the target blood oxygen concentration within an upper target blood oxygen concentration of the target blood oxygen concentration range and a lower target blood oxygen concentration of the target blood oxygen concentration range.

[0398] Generally, the target blood oxygen concentration value is received or determined prior to or at the beginning of a treatment period, but can be received at any time during the treatment period.

[0399] During the treatment period, the blood oxygen concentration controller can also receive as inputs measured oxygen concentration reading(s) from the gas composition sensor, and measured blood oxygen concentration reading(s) and signal quality reading(s) from the patient sensor. In some configurations, the blood oxygen concentration controller can receive a target oxygen concentration as an input. In this case, the output of the blood oxygen concentration controller can be provided directly back to the blood oxygen concentration controller as an input. Based at least in part on these inputs, the blood oxygen concentration controller can output a target oxygen concentration to a second control loop.

[0400] The second control loop can be implemented by a respiratory gas oxygen concentration controller. The oxygen concentration controller can be configured to control the oxygen concentration from an initial oxygen concentration to a target oxygen concentration.

[0401] The blood oxygen concentration controller can be a controller separate from the controller 13, or can be part of the controller 13.

[0402] The oxygen concentration controller can be a controller separate from the controller 13, or can be part of the controller 13.

[0403] The initial oxygen concentration can be a measured oxygen concentration. In some embodiments, the initial oxygen concentration will be a result of a previous control of the oxygen concentration. In some embodiments, for example at system start-up or when no supplemental oxygen source is connected, the initial oxygen concentration can be substantially the same as the concentration of ambient air.

[0404] The target oxygen concentration can be a target oxygen concentration provided by the blood oxygen concentration controller (e.g., Fd02).

[0405] The oxygen concentration controller can receive an input of a measured oxygen concentration of the breathing gas and an input of a target oxygen concentration of the breathing gas. The breathing gas oxygen concentration controller can then output an oxygen inlet valve control signal to control operation of the oxygen valve based on a difference between the measured oxygen concentration value and the target oxygen concentration value. When the respiratory therapy device is operating in an automatic mode, the oxygen concentration controller can receive the target oxygen concentration value output from the first control loop. The breathing gas oxygen concentration controller can also receive additional parameters, such as a flow rate value, gas properties, and / or a measured oxygen concentration. The gas properties can include a temperature of the gas at the 02 inlet and / or an oxygen content of the supply source. The gas supply source connected to the oxygen inlet valve can be an oxygen enriched gas flow, where the oxygen content of the supply source can be less than pure oxygen (i.e., 100%). For example, the oxygen supply source can be an oxygen enriched gas flow with an oxygen content less than 100% and greater than 21%.

[0406] From at least some of the inputs, the breathing gas oxygen concentration controller can determine an oxygen flow rate required to reach the target oxygen concentration. The oxygen concentration controller can use the flow rate input to alter the valve control signal. If the flow rate changes, the oxygen concentration controller can automatically calculate a new required oxygen flow rate needed to maintain the target oxygen concentration at the new flow rate without having to wait for feedback from a gas concentration sensor, such as a measured oxygen concentration value. The oxygen concentration controller can then output an altered valve control signal to control the valve based on the new flow rate. In some configurations, the control signal of the oxygen concentration controller can set a current of the oxygen valve in order to control operation of the oxygen valve. Additionally or alternatively, the oxygen concentration controller can detect a change in the measured oxygen concentration and alter the position of the valve accordingly. During a manual mode, the second control loop can operate independently without receiving a target oxygen concentration from the first control loop. Instead, the target oxygen concentration can be received from a user input or a default value.

[0407] During the treatment period, the blood oxygen concentration and oxygen concentration controller can continue to automatically control operation of the flow therapy apparatus until the end of the treatment period or an event triggers a change from the automatic mode to the manual mode.

[0408] The respiratory gas oxygen concentration controller can be configured to control the oxygen concentration in the respiratory gas to be within a target oxygen concentration range. The target oxygen concentration range can comprise an upper target oxygen concentration and / or a lower target oxygen concentration.

[0409] The respiratory assistance apparatus can further comprise at least one valve tuning arrangement (as described in more detail below).

[0410] The valve tuning arrangement can be controlled by the controller to vary the amount of supplemental oxygen provided to the respiratory gas from the oxygen source.

[0411] The valve tuning arrangement can be in fluid communication with the blower,

[0412] The valve tuning arrangement can be controllable to adjust the amount of oxygen in the introduced gas flow.

[0413] The valve tuning arrangement can comprise one or more actuators.

[0414] The controller can be configured to vary the amount of supplemental oxygen provided to the respiratory gas from the oxygen source to control the oxygen concentration of the respiratory gas.

[0415] The respiratory therapy system 1 can comprise a predictive alarm system. In particular, the respiratory therapy apparatus 10 can comprise a predictive alarm system. The predictive alarm system can generate an alarm based on an estimated future value of the patient blood oxygen concentration.

[0416] The predictive alarm system can be part of the controller 13 or part of a separate alarm module.

[0417] The controller 13 can be configured to estimate the effect of a change in the oxygen concentration of the respiratory gas on the patient blood oxygen concentration.

[0418] The controller 13 can be configured to estimate the effect of a past change (e.g. a series of changes) in the oxygen concentration of the respiratory gas on the patient blood oxygen concentration.

[0419] The controller 13 can be configured to estimate a maximum future value of the patient blood oxygen concentration based on the effect of a past change (e.g. a series of changes) in the oxygen concentration of the respiratory gas and a target oxygen concentration range for the respiratory gas.

[0420] The controller 13 can also take into account the patient blood oxygen (i.e. as measured by the sensor).

[0421] In some embodiments, the patient blood oxygen can be determined over a period of time.

[0422] The controller 13 can be configured to control the oxygen concentration of the breathing gas to a target oxygen concentration.

[0423] A change in the oxygen concentration of the breathing gas (a change in the oxygen concentration provided) can cause a corresponding change in the patient’s blood oxygen concentration.

[0424] If the change is an increase in the oxygen concentration of the breathing gas (e.g. as shown by the increase 921), then the patient’s blood oxygen concentration will increase correspondingly. FIG. 2A

[0425] If the change is a decrease in the oxygen concentration of the breathing gas (e.g. as shown by the decrease 931), then the patient’s blood oxygen concentration will decrease correspondingly. FIG. 2B

[0426] FIG. 2A An example increase in the oxygen concentration of the breathing gas over time (shown as a step change) is shown (e.g. controlled by the controller to a target oxygen concentration of the breathing gas), and the corresponding effect on the patient’s blood oxygen concentration over time.

[0427] At time t1, the controller 13 controls the oxygen concentration of the breathing gas from an initial oxygen concentration 920 to a higher target oxygen concentration 922 by a step change 921. As shown by the change in blood oxygen concentration over time, the effect of the change in oxygen concentration 921 on the blood oxygen concentration is gradual over time, with the estimated blood oxygen concentration increasing over time from t1 to t3. FIG. 2A

[0428] An example decrease in the oxygen concentration of the breathing gas over time (shown as a step change) is shown (e.g. controlled by the controller to a target oxygen concentration of the breathing gas), and the corresponding effect on the patient’s blood oxygen concentration over time. FIG. 2B At time t1, the controller 13 controls the oxygen concentration of the breathing gas from an initial oxygen concentration 930 to a lower target oxygen concentration 932 by a step change 931. As shown by the change in blood oxygen concentration over time, the effect of the change in oxygen concentration 931 on the blood oxygen concentration is gradual over time, with the estimated blood oxygen concentration 933 decreasing over time from t1 to t3. Time t4 represents the time at which the change in the oxygen concentration of the breathing gas has had its full effect on the estimated blood oxygen concentration 933.

[0429]

[0430] And FIG. 2A A single step change in the oxygen concentration over time is shown. It will be appreciated that the controller can perform a series of changes over a period of time (e.g. as shown by the series of changes 921, 922, 923). FIG. 2B FIG. 3

[0431] ​​​​FIG. 3 A series of example variations in the oxygen concentration of the breathing gas over time (e.g. target oxygen concentrations of the breathing gas controlled by the controller) are shown, and the corresponding effect on the patient blood oxygen concentration over time.

[0432] At time tl, the controller 13 controls the oxygen concentration of the breathing gas to a higher oxygen concentration of the breathing gas by a step change 939, followed by a further step change 939’ at t2 controlling the oxygen concentration of the breathing gas to a higher oxygen concentration of the breathing gas, followed by a further step change 939” at t3 controlling the oxygen concentration of the breathing gas to a lower oxygen concentration of the breathing gas, followed by a further step change 939”’ at t4 controlling the oxygen concentration of the breathing gas to a lower oxygen concentration of the breathing gas.

[0433] The controller 13 can perform these variations in the oxygen concentration of the breathing gas based on the control of the patient blood oxygen concentration (as described above).

[0434] The controller 13 can perform these variations to reach a target oxygen concentration of the breathing gas.

[0435] Although FIG. 2A , FIG. 2B and FIG. 3 the oxygen concentration of the breathing gas is shown as varying with step changes, these variations can occur over a period of time. In some embodiments, the control of the oxygen concentration of the breathing gas can be continuous.

[0436] During operation of the apparatus 10, the controller 13 can store the oxygen concentration of the breathing gas as stored oxygen concentration data.

[0437] The controller 13 can also store a related time stamp. The controller 13 can store the oxygen concentration of the breathing gas and the related time stamp as stored oxygen concentration data. For example, the stored oxygen concentration data can comprise one or more oxygen concentrations of the breathing gas, each oxygen concentration having a related time stamp.

[0438] The time stamp can comprise information about the time at which the oxygen concentration of the breathing gas was measured (e.g. by a sensor) or determined (e.g. calculated as a target).

[0439] Referring to FIG. 4A , the determination of the estimated future value of the patient blood oxygen concentration is shown in more detail.

[0440] As FIG. 4A shown, the determination of the estimated future value can be based on the effect of a single variation in the oxygen concentration of the breathing gas or the effect of one or more variations in the oxygen concentration of the breathing gas over a period of time.

[0441] At block 901, the controller 13 determines an initial oxygen concentration of the breathing gas. As discussed above, the initial oxygen concentration can be higher than the oxygen concentration of ambient air if the flow therapy device 10 has been operating. Alternatively, the oxygen concentration can be substantially the same as the oxygen concentration of ambient air if the flow therapy device 10 has not been operating.

[0442] The initial oxygen concentration can be determined from a signal from a gas composition sensor (as described above). The controller 13 can monitor readings from the gas composition sensor to determine the initial oxygen concentration.

[0443] At block 902, the controller 13 determines a target oxygen concentration of the breathing gas. As discussed above, the target oxygen concentration of the breathing gas can be a target oxygen concentration (e.g. Fd02) provided by a blood oxygen concentration controller.

[0444] The target oxygen concentration can be determined from a signal from a gas composition sensor (as described above).

[0445] At block 903, the controller 13 determines a patient blood oxygen concentration (e.g. Sp02 of the patient). In some embodiments, the patient blood oxygen concentration can be determined over a predetermined time.

[0446] At block 904, the controller determines an estimated future value of the patient blood oxygen concentration (described in more detail below).

[0447] The controller 13 can be configured to calculate the estimated future value of the patient blood oxygen concentration based on a difference between the initial oxygen concentration of the breathing gas and the target oxygen concentration of the breathing gas.

[0448] Additionally or alternatively, the controller 13 can be configured to calculate the estimated future value of the patient blood oxygen concentration based on a measurement indicative of the patient blood oxygen concentration.

[0449] In some embodiments, the estimated future value of the patient blood oxygen concentration (BOC) can be based on the following equation:

[0450] Estimated future BOC = current BOC + K (AO2 concentration)

[0451] where:

[0452] Estimated future BOC is an estimated value of the patient blood oxygen concentration,

[0453] current BOC is the current patient blood oxygen concentration.

[0454] K is a factor or function that defines a relationship between a change in the oxygen concentration of the supplied gas and an effect on the patient blood oxygen concentration.

[0455] Δ02concentration is a change in the oxygen concentration of the breathing gas (e.g., a difference between an initial oxygen concentration of the breathing gas and a target oxygen concentration of the breathing gas).

[0456] The estimated future value of the patient blood oxygen concentration can be further based on a time since the controller controlled the oxygen concentration of the breathing gas to the target oxygen concentration. With reference to the above equation, the factor K can be based on the time since the change in the oxygen concentration of the breathing gas occurred.

[0457] K can be a linear or non-linear function, for example, in cases where an increase in the supplied oxygen results in a corresponding increase in the patient blood oxygen concentration.

[0458] The estimated future value of the patient blood oxygen concentration can be based on an estimated oxygen efficiency of the patient. The estimated oxygen efficiency is an indication of a relationship between the change in the oxygen concentration of the breathing gas and the change in the patient blood oxygen concentration. The estimated oxygen efficiency of the patient can be included as part of the factor or function K as described above.

[0459] With reference to FIG. 4B Another determination of the estimated future value of the patient blood oxygen concentration is shown in more detail.

[0460] At block 911, the controller 13 can update the stored breathing gas oxygen concentration data (as discussed in more detail above).

[0461] The controller 13 can store the breathing gas oxygen concentration data from the start-up of the device, or from the start of therapy, or a predetermined amount of time (e.g., the past 15 minutes) prior to the current time.

[0462] The controller 13 can update the stored breathing gas oxygen concentration data at regular time intervals or irregular time intervals. In some embodiments, the controller can update the stored breathing gas oxygen concentration data in real-time.

[0463] In some embodiments, updating the stored breathing gas oxygen concentration data can include adding one or more additional oxygen concentrations of the breathing gas and associated time stamps (e.g., a newly measured oxygen concentration of the breathing gas and the time of measurement as a time stamp).

[0464] At block 912, the controller 13 determines the patient blood oxygen concentration (e.g., the Sp02 of the patient).

[0465] At block 913, the controller determines the estimated future value of the patient blood oxygen concentration (as described in more detail below).

[0466] In some embodiments, the estimated future value of the patient blood oxygen concentration (BOC) can be based on the following equation:

[0467] Estimated future BOC = f (BOC, 02concentration, C)

[0468] wherein:

[0469] Estimated future BOC is an estimate of the patient's blood oxygen concentration,

[0470] BOC is the patient's blood oxygen concentration (e.g. measured blood oxygen concentration) during treatment or over a predetermined time,

[0471] 02concentration is the oxygen concentration of the breathing gas (e.g. target oxygen concentration) during treatment or over a predetermined time,

[0472] C can comprise constants and / or functions (e.g. a patient's oxygen efficiency and / or a haemoglobin saturation function).

[0473] The equation shows that the estimated future BOC is a function of the patient's blood oxygen concentration, the oxygen concentration of the breathing gas, and constants and / or functions C.

[0474] In some embodiments, the controller is configured to calculate an estimated future value of the patient's blood oxygen concentration based on stored breathing gas oxygen concentration data and measurements indicative of the patient's blood oxygen concentration.

[0475] The oxygen concentration of the breathing gas of the stored breathing gas oxygen concentration data can be weighted based on the associated time stamp.

[0476] The controller can determine a series of changes in the oxygen concentration of the breathing gas in the stored breathing gas oxygen concentration data.

[0477] The time stamp based weighting can be inversely proportional to time, as the oxygen concentration of the breathing gas has changed.

[0478] That is, in the calculation of the future value of the blood oxygen concentration, relatively earlier changes will be given a relatively lower weight, as these changes can have (at least partially) already had an impact on the patient's blood oxygen concentration compared to relatively newer changes.

[0479] In some embodiments, the estimated future value of the patient's blood oxygen concentration (BOC) can be based on a sum of changes in the oxygen concentration of the breathing gas.

[0480] Reference FIG. 4C shows another determination of the estimated future value of the patient's blood oxygen concentration in more detail.

[0481] At block 916, the controller 13 performs an estimate update phase.

[0482] The estimate update phase can be configured to determine one or more variables of the apparatus 10 and update the sum of changes in the oxygen concentration of the breathing gas accordingly.

[0483] At block 917, the controller 13 determines the patient blood oxygen concentration.

[0484] At block 918, the controller 13 estimates a future value of the patient blood oxygen concentration based on the running total of changes in oxygen concentration, which has been updated in the estimation update phase at block 916.

[0485] At FIG. 4D The estimation update phase 916 is shown in more detail in

[0486] At block 990, an attenuation factor is applied to the current running total of changes in oxygen concentration of the breathing gas.

[0487] The attenuation factor attenuates the running total of changes in oxygen concentration of the breathing gas at each estimation update phase to account for changes in oxygen concentration of the breathing gas that have no effect on the patient blood oxygen concentration.

[0488] At block 991, the controller 13 determines the oxygen concentration of the breathing gas. As discussed above, the oxygen concentration of the breathing gas can be the measured oxygen concentration (e.g. measured by a gas composition sensor) or the target oxygen concentration (i.e. set by the controller 13).

[0489] At block 992, the controller 13 determines the oxygen concentration of the breathing gas at the previous estimation update.

[0490] At block 993, the controller 13 determines the difference between the oxygen concentration of the breathing gas and the oxygen concentration of the breathing gas at the previous estimation update.

[0491] At block 994, the controller 13 updates the running total of changes in oxygen concentration of the breathing gas by adding the difference between the oxygen concentration of the breathing gas and the oxygen concentration of the breathing gas at the previous estimation update, and attenuates the running total of changes in oxygen concentration of the breathing gas.

[0492] The running total of changes in oxygen concentration of the breathing gas can be indicative of changes in oxygen provided to the user that have not yet had an effect on the patient’s blood oxygen concentration.

[0493] The estimated future value of the patient blood oxygen concentration can be based on the patient’s oxygen efficiency and / or a haemoglobin saturation function.

[0494] The estimation update phase can be represented by the following equation.

[0495] (∑ΔO2 concentration) t = a(∑ΔO2 concentration) t-1 + ((O2 concentration) t - (O2 concentration) t-1 )

[0496] wherein:

[0497] ∑ΔO2concentration)tis the sum of changes in oxygen concentration of the respiratory gas at the current estimate update stage (at time t)

[0498] a is an attenuation factor

[0499] ∑ΔO2concentration)t-1is the sum of changes in oxygen concentration of the respiratory gas at the previous estimate update stage (at time t-1)

[0500] (O2concentration)tis the oxygen concentration of the respiratory gas at the current estimate update stage (at time t)

[0501] (O2concentration)t-1is the oxygen concentration of the respiratory gas at the previous estimate update stage (at time t-1).

[0502] The controller 13 can be configured to perform the estimate update stage at regular time intervals or irregular time intervals.

[0503] In some embodiments, the controller 13 can be configured to perform the estimate update stage about every 0.5 seconds to about every 2 seconds, or every 1 second to about every 1.5 seconds, or every 0.5 seconds, or every 1 second, or every 1.5 seconds.

[0504] In some embodiments, the attenuation factor can provide exponential decay.

[0505] The attenuation factor can be based on the time between estimate update stages.

[0506] In some embodiments, the attenuation factor can be selected such that the magnitude of any change in the oxygen concentration of the respiratory gas decays to 36% of its initial value within 45 seconds.

[0507] The stored oxygen concentration data can be transmitted by the respiratory device arrangement to one or more servers, or a patient monitoring unit, and / or a nurse monitoring station.

[0508] The controller 13 can be configured to compare the estimated future value of the patient blood oxygen concentration to a blood oxygen concentration alert range.

[0509] The controller 13 can generate an alert output if the estimated future value of the patient blood oxygen concentration is not within the blood oxygen concentration alert range.

[0510] For example, in FIG. 5A the blood oxygen concentration alert range can comprise an upper blood oxygen concentration alert threshold 996 and a lower blood oxygen concentration alert threshold 997.

[0511] Alarm output can be based on the difference between the estimated future value and the upper limit blood oxygen concentration alarm threshold 996 (or the lower limit blood oxygen concentration alarm threshold 997), as well as a measure of time.

[0512] The time it takes to generate an alarm output may be inversely proportional to the difference. For example, if the difference is relatively small, the alarm may take a longer time to activate, while if the difference is relatively large, the alarm may take a shorter time to activate.

[0513] In some embodiments, if the estimated blood oxygen concentration is close to the alarm threshold, the alarm will take a relatively long time to activate.

[0514] In some embodiments, if the estimated blood oxygen concentration is far from the alarm threshold, the alarm will take a relatively short time to activate.

[0515] The upper limit oxygen concentration alarm threshold 996 and / or the lower limit oxygen concentration alarm threshold 997 can be based on the time since the controller began to control the oxygen concentration of the breathing gas to the target oxygen concentration. For example, the lower limit oxygen concentration alarm may increase over time.

[0516] Alarm thresholds can be determined based on the amount of change in target oxygen concentration (e.g., the difference between target oxygen concentration and initial oxygen concentration).

[0517] Alternatively, the alarm threshold can be determined based on the target oxygen concentration.

[0518] Alternatively, the alarm threshold can be determined based on the current oxygen concentration in the gas.

[0519] Alarm thresholds can be based on target blood oxygen concentration.

[0520] For example, FIG. 5B As shown, controller 13 can be configured to generate an alarm output based on a comparison of an estimated future value of the patient's blood oxygen concentration with a blood oxygen concentration alarm threshold 998.

[0521] The controller 13 can be configured to generate the alarm output if the estimated future value of the patient's blood oxygen concentration is higher or lower than the blood oxygen concentration threshold.

[0522] Alarm thresholds can be based on the time since the controller began controlling the oxygen concentration of the breathing gas to the target oxygen concentration.

[0523] Alarm outputs can be transmitted to one or more servers that communicate with the respiratory therapy device, or to a patient monitoring unit and / or a nurse monitoring station.

[0524] Alarm thresholds can be determined based on the amount of change in target oxygen concentration (e.g., the difference between target oxygen concentration and initial oxygen concentration).

[0525] Additionally or alternatively, the alarm threshold can be determined based on the target oxygen concentration.

[0526] Additionally or alternatively, the alarm threshold can be determined based on the current gas oxygen concentration.

[0527] The alarm range can be based on the target blood oxygen concentration.

[0528] The alarm output can be transmitted to one or more servers in communication with the respiratory therapy device, or a patient monitoring unit, and / or a nurse monitoring station.

[0529] The blood oxygen concentration alarm threshold can be based on the target blood oxygen concentration. For example, the blood oxygen concentration alarm threshold can be a predetermined amount of percentage or absolute difference from the target blood oxygen concentration.

[0530] The controller can also be configured to determine the effect of any further possible changes in the oxygen concentration of the respiratory gas within the target oxygen concentration range of the respiratory gas on the patient blood oxygen concentration.

[0531] For example, if the upper limit target oxygen concentration of the target oxygen concentration range is higher than the oxygen concentration of the respiratory gas, the controller can determine the effect of increasing the oxygen concentration of the respiratory gas to the upper limit target oxygen concentration on the patient blood oxygen concentration.

[0532] The alarm output is described in more detail below.

[0533] Reference is made to FIG. 6 determination of the maximum or minimum future value of the patient blood oxygen concentration for the corresponding target oxygen range is shown in more detail.

[0534] The maximum or minimum future value can be after any changes in the oxygen concentration of the respiratory gas have had an effect on the patient blood oxygen (e.g. when the patient’s blood oxygen no longer changes or reaches a steady state).

[0535] At block 941, the controller 13 determines a target oxygen concentration range of the respiratory gas (described in more detail above). For example, the target oxygen concentration range can be provided as an input from a user, or can be determined by the controller 13 or another controller 13 of the device.

[0536] At block 942, the controller 13 determines the patient blood oxygen concentration (e.g. with a sensor such as a pulse oximeter).

[0537] At block 943, the controller 13 determines the oxygen concentration of the respiratory gas. If the controller 13 is in the process of changing or controlling the oxygen concentration of the respiratory gas, the oxygen concentration of the respiratory gas can be the target oxygen concentration of the respiratory gas.

[0538] At block 944, the controller 13 determines an estimated maximum or minimum future value of the patient blood oxygen concentration. The estimated maximum or minimum future value of the patient blood oxygen concentration can be based on the target oxygen concentration range of the breathing gas, the current oxygen concentration of the breathing gas, and the current patient blood oxygen concentration.

[0539] FIG. 7 An example is shown in which the controller 13 controls the oxygen concentration of the breathing gas from an initial oxygen concentration 920 to a target oxygen concentration 921. The target oxygen concentration 921 can be within the target oxygen concentration range. As discussed above, the target oxygen concentration range can include an upper target oxygen concentration 935 and / or a lower target oxygen concentration 936.

[0540] The controller can determine a difference between the upper target oxygen concentration 935 and the target oxygen concentration 921 (as indicated by reference numeral 937).

[0541] The controller can determine a difference between the lower target oxygen concentration 936 and the target oxygen concentration 921 (as indicated by reference numeral 938).

[0542] The controller 13 can be configured to calculate an estimated maximum or minimum future value of the patient blood oxygen concentration for the target oxygen concentration range. That is, given the possible further variation of the provided oxygen concentration that the device can provide while still being within the target oxygen concentration range, calculate an estimate of the maximum or minimum future value of the patient blood oxygen concentration.

[0543] This estimated maximum or minimum future value can be useful in providing information to the user about the estimated impact that the device can provide on the patient blood oxygen concentration within the target oxygen concentration range of the breathing gas input by the user. For example, if the estimated maximum or minimum future value is not acceptable to the user, the user can be notified and the input parameters of the system can be changed, or the therapy modified.

[0544] The controller 13 can be configured to calculate an estimated maximum future value of the patient blood oxygen concentration for the target oxygen concentration range. The estimated maximum future value of the patient blood oxygen concentration for the target oxygen concentration range can be based on a difference between the target oxygen concentration and the upper target oxygen concentration, and the measurement indicative of the patient blood oxygen concentration.

[0545] The estimated maximum or minimum future value of the patient blood oxygen concentration can additionally be based on the measurement indicative of the patient blood oxygen concentration.

[0546] The determination of the estimated maximum or minimum future value of the patient blood oxygen concentration can include aspects of the above-described methods for determining an estimated future value of the patient blood oxygen concentration.

[0547] The maximum or minimum future value of the estimate of the patient blood oxygen concentration can be based on past changes in oxygen concentration of the breathing gas that have already occurred (e.g. stored breathing gas oxygen concentration data), and potential changes that can occur in the future (e.g. changes that can occur when controlling the oxygen concentration of the breathing gas within the target oxygen concentration range of the breathing gas).

[0548] In some embodiments, the maximum estimated future value of the patient blood oxygen concentration (BOC) can be based on the following equation:

[0549]

[0550] where:

[0551] is the estimated maximum value of the patient blood oxygen concentration for the corresponding target oxygen range.

[0552] Current BOC is the current patient blood oxygen concentration.

[0553] P is a factor or function that defines the relationship between a further potential increase in the oxygen concentration of the supplied gas and the effect on the patient blood oxygen concentration.

[0554] Upper target O2 concentration is the upper target oxygen concentration (of the target oxygen concentration range).

[0555] Current O2 concentration is the current oxygen concentration of the breathing gas.

[0556] The controller 13 can be configured to calculate an estimated minimum future value of the patient blood oxygen concentration for the target oxygen concentration range. The estimated minimum future value of the patient blood oxygen concentration can be based on the difference between the target oxygen concentration and the lower target oxygen concentration, and the measurement indicative of the patient blood oxygen concentration.

[0557] In some embodiments, the maximum estimated future value of the patient blood oxygen concentration can be based on the following equation:

[0558]

[0559] where:

[0560] is the estimated minimum value of the patient blood oxygen concentration for the corresponding target oxygen range.

[0561] Current BOC is the current patient blood oxygen concentration.

[0562] Q is a factor or function that defines the relationship between a further potential decrease in the oxygen concentration of the supplied gas and the effect on the patient blood oxygen concentration.

[0563] Lower target O 2The concentration is a lower limit target oxygen concentration of the optional target oxygen concentration range.

[0564] The current O 2 The concentration is a current oxygen concentration of the breathing gas.

[0565] FIG. 8A A target oxygen concentration range of the breathing gas is shown, which is defined by an upper limit target oxygen concentration 935 and a lower limit target oxygen concentration 936.

[0566] FIG. 8A And FIG. 8B An example of calculating an estimated minimum or maximum future value of the patient blood oxygen concentration is shown in the middle. FIG. 8A The oxygen concentration 922 of the breathing gas over time is shown. In this example, the controller 13 controls the oxygen concentration 922 of the breathing gas to be a constant value (i.e. there is no change).

[0567] Over time, the oxygen concentration 922 of the breathing gas corresponds to the blood oxygen concentration 932 of the patient. Because the oxygen concentration 922 of the breathing gas is constant, the blood oxygen concentration 932 of the patient is also constant.

[0568] As described above, the controller 13 can calculate a difference 937 between the upper limit target oxygen concentration 935 of the breathing gas and the oxygen concentration 922 of the breathing gas (e.g. the current oxygen concentration of the breathing gas). This difference 937 can then be used, along with the measurement 923 indicative of the patient blood oxygen concentration, to estimate a maximum future value 950 of the patient blood oxygen concentration.

[0569] As described above, the controller 13 can calculate a difference 938 between the lower limit target oxygen concentration 936 of the breathing gas and the oxygen concentration 922 of the breathing gas (e.g. the current oxygen concentration of the breathing gas). This difference 938 can then be used, along with the measurement 923 indicative of the patient blood oxygen concentration, to estimate a minimum future value 951 of the patient blood oxygen concentration.

[0570] In some embodiments, as described above, the estimated maximum or minimum future value of the patient blood oxygen concentration can be based on, for example, an estimated future value of the patient blood oxygen concentration (based on recent changes in the oxygen concentration). This allows for the estimation of a maximum future value or a minimum future value of the patient blood oxygen concentration to account for past changes or recent changes in the oxygen concentration of the breathing gas (as described above).

[0571] In some embodiments, the estimated maximum or minimum future value of the patient blood oxygen concentration can be based on (as described in more detail above) stored breathing gas oxygen concentration data.

[0572] In some embodiments, the estimated maximum or minimum future value of the patient blood oxygen concentration can be based on (as described in more detail above) the sum of the changes in the oxygen concentration of the respiratory gas.

[0573] The estimated maximum or minimum future value of the patient blood oxygen concentration can additionally be based on a measurement indicative of the patient blood oxygen concentration and the estimated future value of the patient blood oxygen concentration (as described above).

[0574] Reference is made to FIG. 9A determination of the maximum or minimum future value of the patient blood oxygen concentration for a corresponding target oxygen concentration range of the respiratory gas is shown in more detail.

[0575] At block 960, the controller 13 can update the stored respiratory gas oxygen concentration data (as discussed in more detail above).

[0576] The controller 13 can store respiratory gas oxygen concentration data from machine start, or from treatment start, or for a predetermined amount of time (e.g. last 15 minutes) from the current time.

[0577] The controller 13 can store respiratory gas oxygen concentration data at regular time intervals or irregular time intervals. In some embodiments, the controller can update the stored respiratory gas oxygen concentration data in real time.

[0578] At block 961, the controller 13 determines the patient blood oxygen concentration (e.g. Sp02 of the patient).

[0579] At block 962, the controller 13 determines (as described in more detail above) a target oxygen concentration range of the respiratory gas. For example, the target oxygen concentration range of the respiratory gas can be provided as an input from a user, or can be determined by the controller 13 or another controller 13 of the device.

[0580] At block 963, the controller 13 calculates an estimated maximum or minimum future value of the patient blood oxygen concentration (as described elsewhere in the specification).

[0581] In some embodiments, the estimated maximum or minimum future value of the patient blood oxygen concentration (BOC) can be based on the following equation:

[0582] Estimated maximum or minimum future BOC = f (BOC, 02 concentration, target 02 concentration, C)

[0583] where:

[0584] Estimated maximum or minimum future BOC is the estimated maximum or minimum future value of the patient blood oxygen concentration,

[0585] BOC is the blood oxygen concentration of the patient during the treatment or for a predetermined time,

[0586] O2concentration is the oxygen concentration of the breathing gas during the treatment or within a predetermined time,

[0587] target O2concentration is the target oxygen concentration range of the breathing gas

[0588] C can comprise constants and / or functions (e.g. oxygen efficiency and / or haemoglobin saturation functions of the patient).

[0589] This equation shows that the estimated maximum or minimum future BOC is a function of the patient blood oxygen concentration, the oxygen concentration of the breathing gas, the target oxygen concentration range of the breathing gas, and constants and / or functions C.

[0590] In some embodiments, the controller is configured to calculate an estimated maximum or minimum future value of the patient blood oxygen concentration based on the stored breathing gas oxygen concentration data, the target oxygen concentration range of the breathing gas, and the measurement indicative of the patient blood oxygen concentration.

[0591] The oxygen concentration of the breathing gas of the stored breathing gas oxygen concentration data can be weighted based on the associated time stamp.

[0592] The controller can determine a series of changes in the oxygen concentration of the breathing gas in the stored breathing gas oxygen concentration data.

[0593] The time stamp based weighting can be inversely proportional to the time, as the oxygen concentration of the breathing gas has changed.

[0594] That is, in calculating the estimated maximum or minimum future blood oxygen concentration, relatively older changes will be given a relatively lower weight compared to relatively newer changes, as these relatively older changes can have already (at least partially) had an impact on the patient blood oxygen concentration.

[0595] Reference is made to FIG. 9B for a further determination of an estimated maximum or minimum future value of the patient blood oxygen concentration.

[0596] At block 970, the controller 13 performs an estimate update phase (as discussed in more detail above and as shown in FIG. 4C ).

[0597] At block 971, the controller 13 determines the patient blood oxygen concentration.

[0598] At block 972, the controller 13 determines the target oxygen concentration range of the breathing gas.

[0599] At block 973, the controller 13 estimates a future value of the patient blood oxygen concentration based on the sum of changes in oxygen concentration (which has been updated in the estimate update phase at block 916).

[0600] The controller 13 can calculate a difference 937 between the upper target oxygen concentration 935 of the breathing gas and the oxygen concentration 922 of the breathing gas (e.g., the current oxygen concentration of the breathing gas). This difference 937 can then be used in conjunction with the sum of the measurements indicative of the patient's blood oxygen concentration 923 and the change in the oxygen concentration of the breathing gas to estimate a maximum future value 950 of the patient's blood oxygen concentration.

[0601] The controller 13 can calculate a difference 938 between the lower target oxygen concentration 936 of the breathing gas and the oxygen concentration 922 of the breathing gas (e.g., the current oxygen concentration of the breathing gas). This difference 938 can then be used in conjunction with the sum of the measurements indicative of the patient's blood oxygen concentration 923 and the change in the oxygen concentration of the breathing gas to estimate a minimum future value 951 of the patient's blood oxygen concentration.

[0602] The estimated maximum future value and / or the estimated minimum future value can be updated in real-time. As such, the estimated maximum future value and / or the estimated minimum future value can be continually updated during operation of the device 10.

[0603] The estimated maximum future value and / or the estimated minimum future value can be based on an oxygen efficiency ratio.

[0604] In some embodiments, the oxygen efficiency ratio (including the oxygen efficiency ratio as described above) can be input by a user.

[0605] In some embodiments, the oxygen efficiency ratio can be calculated based on the measured blood oxygen concentration and the lower target oxygen concentration of the breathing gas (or the upper target oxygen concentration of the breathing gas).

[0606] In another embodiment, the flow therapy device 10 can determine an oxygen efficiency associated with the patient.

[0607] The system can calculate an estimate of the patient's oxygen efficiency (ξ02) along with other parameters. Generally, the oxygen efficiency can be calculated based on the measured blood oxygen concentration (e.g., Sp02) of the patient and the measured oxygen concentration (e.g., Fd02) of the breathing gas. In one configuration, the oxygen efficiency is determined based on the measured Sp02 of the patient divided by the measured Fd02.

[0608] The oxygen efficiency of a patient in need of supplemental oxygen can be less than the oxygen efficiency of a healthy individual. For example, in a healthy individual, a change in Fd02 can cause a doubling of the change in Sp02, which would be the same as Sp02 for a patient with low oxygen efficiency. Measuring the oxygen efficiency of a patient allows for more effective implementation of a closed loop oxygen control system.

[0609] As FIG. 10AAs demonstrated, the controller 13 can calculate the patient's oxygen efficiency. The controller can receive measured SpO2 values. The measured FdO2 values can be received from the gas composition sensor. Instantaneous oxygen efficiency can then be calculated based on the measured SpO2 and measured FdO2 values. The patient's overall oxygen efficiency can then be estimated by applying a running filter to the instantaneous oxygen efficiency data. Filtering the instantaneous oxygen efficiency data can reduce fluctuations when estimating the patient's overall oxygen efficiency. The controller can also prioritize recent data. The instantaneous oxygen efficiency data can be weighted according to the signal quality of the pulse oximeter, such that measurements of instantaneous oxygen efficiency according to data with low signal quality have a reduced impact on the estimation of the patient's overall oxygen efficiency. The instantaneous oxygen efficiency data can also be weighted based on the size of recent changes in FdO2, such that measurements of instantaneous oxygen efficiency according to data after a large change in FdO2 have a reduced impact on the estimation of the patient's overall oxygen efficiency. This is due to the delay between when a change is made in FdO2 and when there is a change in measured SpO2. The controller can also take into account whether the patient is wearing a cannula when estimating the patient's oxygen efficiency. For example, the controller can disregard efficiency data from periods when the patient is not wearing a cannula.

[0610] The apparatus can continually monitor and update the estimate of the patient's overall oxygen efficiency. The patient's overall oxygen efficiency can be used by multiple parts of the closed loop control system, such as in the predictive model, tuning of the PID coefficients, and / or step increase to the feed forward stage. The patient's overall oxygen efficiency can be continually updated as the estimate of the patient's instantaneous oxygen efficiency changes. The controller can start from an initial estimate of the patient's oxygen efficiency based on typical oxygen efficiency for patients who require supplemental oxygen. The overall oxygen efficiency can then be updated as data is received. A higher estimate of oxygen efficiency can result in smaller changes in FdO2, which can reduce the risk of the patient receiving too much oxygen. A lower estimate can result in larger changes in FdO2, which can allow the controller to achieve the target SpO2 more quickly, but can cause overshoot.

[0611] In some configurations, the flow therapy apparatus 10 can have an initial oxygen efficiency calculation phase in order to determine the patient's oxygen efficiency. In some configurations, the oxygen efficiency is not updated after the initial oxygen efficiency calculation.

[0612] The controller can be configured to produce an alarm output.

[0613] The alarm output can comprise an alarm signal.

[0614] The alarm output can have any of the features described above.

[0615] The alarm output can be provided in combination with the alarm output described above.

[0616] The controller 13 can be configured to compare the estimated maximum future value of the patient blood oxygen concentration to an upper target blood oxygen concentration, and to generate an alarm output if the estimated maximum future value of the patient blood oxygen concentration is greater than the upper target blood oxygen concentration.

[0617] The controller 13 can be configured to compare the estimated maximum future value of the patient blood oxygen concentration to a lower target blood oxygen concentration, and to generate an alarm output if the estimated maximum future value of the patient blood oxygen concentration is less than the lower target blood oxygen concentration.

[0618] An alarm parameter of the alarm output can be based on a magnitude of a difference between the estimated maximum future value of the patient blood oxygen concentration and the upper target blood oxygen concentration.

[0619] The controller 13 can be configured to compare the estimated minimum future value of the patient blood oxygen concentration to a lower target blood oxygen concentration, and to generate an alarm output if the estimated minimum future value of the patient blood oxygen concentration is less than the lower target blood oxygen concentration.

[0620] The controller 13 can be configured to compare the estimated minimum future value of the patient blood oxygen concentration to an upper target blood oxygen concentration, and to generate an alarm output if the estimated minimum future value of the patient blood oxygen concentration is greater than the upper target blood oxygen concentration.

[0621] An alarm parameter of the alarm output can be based on a magnitude of a difference between the estimated minimum future value of the patient blood oxygen concentration and the lower target blood oxygen concentration.

[0622] The alarm parameter can be an alarm duration or an alarm intensity.

[0623] The alarm intensity can be an alarm level, for example indicating a severity of the alarm.

[0624] The alarm output can be provided to a display.

[0625] The display can be configured to provide a user interface.

[0626] The alarm output can be configured to produce a sound, or to provide an indication, for example a visual indication.

[0627] The alarm output can be transmitted to one or more servers in communication with the respiratory treatment device, or a patient monitoring unit, and / or a nurse monitoring station.

[0628] The alarm output can be based on a measure of time and a difference between the estimated maximum future value and a lower blood oxygen concentration alarm threshold 931 (or a difference between the estimated minimum future value and an upper blood oxygen concentration alarm threshold 930).

[0629] The time required to produce an alarm output can be inversely proportional to the difference. For example, if the difference is relatively small, the alarm can require a longer time to activate, whereas if the difference is relatively large, the alarm can require a shorter time to activate.

[0630] In some embodiments, if the estimated blood oxygen concentration is close to the alarm threshold, the alarm will require a relatively long time to activate.

[0631] In some embodiments, if the estimated blood oxygen concentration is far from the alarm threshold, the alarm will take a relatively short time to activate.

[0632] An under-oxygen warning alarm output can be provided when the controller 13 predicts that the estimated maximum future value of the patient’s blood oxygen concentration is below the target blood oxygen concentration by more than a threshold amount.

[0633] The under-oxygen warning alarm output can be provided after an under-oxygen warning alarm output time has elapsed during which the estimated maximum future value of the patient’s blood oxygen concentration is below the target blood oxygen concentration by more than a threshold amount.

[0634] The under-oxygen warning alarm threshold amount can have a first threshold corresponding to an under-oxygen first level warning and a second threshold corresponding to an under-oxygen second level warning, wherein the first threshold is greater than the second threshold.

[0635] The under-oxygen first level warning can indicate a larger difference between the estimated maximum future value of the patient’s blood oxygen concentration and the target blood oxygen concentration.

[0636] The under-oxygen second level warning can indicate a smaller difference between the estimated maximum future value of the patient’s blood oxygen concentration and the target blood oxygen concentration.

[0637] The under-oxygen first level warning can have different alarm parameters (e.g. longer alarm time) than the under-oxygen second level warning.

[0638] An over-oxygen warning alarm output can be provided when the controller 13 predicts that the estimated minimum future value of the patient’s blood oxygen concentration is above the target blood oxygen concentration by more than a threshold amount.

[0639] The over-oxygen warning alarm output can be provided after an over-oxygen warning alarm output time has elapsed during which the estimated minimum future value of the patient’s blood oxygen concentration is above the target blood oxygen concentration by more than a threshold amount.

[0640] The over-oxygen warning alarm threshold amount can have a first threshold corresponding to an over-oxygen first level warning and a second threshold corresponding to an over-oxygen second level warning, wherein the first threshold is greater than the second threshold.

[0641] The peroxia first level warning can indicate a larger difference between the estimated minimum future value of the patient's blood oxygen concentration and the target blood oxygen concentration.

[0642] The peroxia second level warning can indicate a smaller difference between the estimated minimum future value of the patient's blood oxygen concentration and the target blood oxygen concentration.

[0643] The peroxia first level warning can have different alarm parameters (e.g. a longer alarm time) than the peroxia second level warning.

[0644] The alarm output can also be generated according to the following equation.

[0645] ∑ 警报 = ∑ (BOC 最小 - estimated maximum future value or minimum future value - β)

[0646] wherein

[0647] ∑ 警报 is the alarm sum,

[0648] BOC 最小 is the minimum BOC threshold, e.g. as user input, or as lower target blood oxygen concentration,

[0649] the estimated maximum future value or minimum future value is the estimated maximum future value or minimum future value as described above,

[0650] β is a sensitivity factor.

[0651] The alarm output can be generated when the alarm sum is above a threshold.

[0652] While the above description relates to a device, it is to be understood that the above description can be implemented as a method.

[0653] A flow therapy device for providing the method as described above is also disclosed.

[0654] The above described embodiments can be at least partially executed on a secondary device 2.

[0655] For example, in contrast to a controller of a breathing assistance device, the calculation of the estimated maximum future value, and / or the estimated minimum future value, and / or the estimated future value can be performed on a secondary device (e.g. as shown in FIG. 25 ).

[0656] As shown in FIG. 25 , the secondary device 2 can comprise a display and / or a controller. The controller may, for example, assume any function of the controller 13 of the breathing assistance device 1.

[0657] As shown in FIG. 25As shown, the respiratory assist device can provide information to the assist device 2 to provide the information needed to calculate the estimated future value of the patient's blood oxygen.

[0658] For example, respiratory assist device 1 can provide the assist device with variables measured by respiratory assist device 1, such as the current blood oxygen concentration of the patient and the target oxygen concentration of the respiratory gas, so that the assist device 2 can perform calculations.

[0659] The respiratory assist device 1 may also provide other information to be displayed on the assist device 2 (e.g., patient blood oxygen concentration, target oxygen concentration of breathing gases, or other variables measured or calculated by the respiratory assist device 1).

[0660] In some embodiments, the breathing device 1 may transmit an alarm output to the auxiliary device 2 (as described in more detail above).

[0661] The auxiliary device 2 can output alarms (e.g., audio and / or visual alarms via the auxiliary device's display and / or speaker).

[0662] In some embodiments, the auxiliary device 2 can determine the alarm output and provide the alarm output to the respiratory assist device 1. The respiratory device 1 can then output the alarm as described above.

[0663] The auxiliary device 2 may be or include a server, or a patient monitoring unit, and / or a nurse monitoring station and / or a mobile device such as a tablet or mobile phone.

[0664] The assistive device 2 can communicate with the breathing device 1 via a wired connection or via a wireless connection (such as Bluetooth or NFC).

[0665] The auxiliary device 2 may be equipped with an app or user interface to display information and / or alarms.

[0666] The auxiliary device 2 can be configured to change at least one parameter of the respiratory assist device (e.g., the target oxygen concentration of the breathing gas).

[0667] Motor and / or sensor module configuration

[0668] FIGS. 11-13 The configuration of the flow therapy device 10 is shown. The flow therapy device includes a main housing 100. The main housing 100 has an upper main housing housing 102 and a lower main housing housing 202.

[0669] like FIG. 11 and FIG. 12 As shown, the lower housing 202 has a motor recess 250 for receiving a removable or non-removable motor and / or sensor module 400, which in... FIGS. 13-15which is shown in FIG. 2 and will be described in further detail below. A recess opening 251 is provided in the bottom wall 230 proximate to its rear edge for receiving a removable or non-removable motor / sensor module 400, which is shown in FIG. 16 and FIG. 18 which is shown in FIG. 2 and will be described in further detail below. A recess opening 251 is provided in the bottom wall 230 proximate to its rear edge for receiving a removable or non-removable motor / sensor module 400, which is shown in

[0670] FIGS. 13-16 The motor and / or sensor module or subassembly 400 is shown in further detail. As discussed above, the lower housing 202 includes a recess 250 for receiving the motor and / or sensor module 400.

[0671] In the form shown in FIGS. 13-16 The motor and / or sensor module 400 includes a stacked arrangement of three main components; a base 403 of the subassembly 400 on which a motor 402 is located, an outlet gas flow path and sensing layer 420 located above the base 403, and a cover layer 440. The base 403, sensing layer 420 and cover layer 440 are assembled together to form a subassembly housing which has a shape that is complementary to the shape of the recess 250 so that the subassembly 400 can be received in the recess 250. The base 403 is configured to close the recess opening 251 when the subassembly 400 is located in the recess 250. The subassembly 400 can be held in place in the recess in any suitable manner, such as with fasteners, clips or a quick release arrangement, or fixed in a non-removable manner.

[0672] The sensing layer includes a gas flow path having one or more sensors arranged to deliver gas to an outlet port of the housing.

[0673] The motor 402 has a body 408 which defines an impeller chamber which houses an impeller. The motor 402 can be any suitable gas blower motor and may, for example, be a motor and impeller assembly of the type described in published PCT specification W02013 / 009193. The contents of that specification are incorporated herein in their entirety by reference.

[0674] The gas outlet 406 is in fluid communication with a gas inlet of an outlet gas flow path and sensing layer 420 which is stacked on top of the motor. This layer 420 includes a body 422 which includes a plurality of mounting legs 425 which can be inserted into a plurality of mounting slots (not shown) of the base 403 to secure the body 422 to the base 403. In one configuration, the body 422 defines a gas flow path which couples the gas outlet 406 with the gas inlet of the outlet gas flow path and sensing layer 420.

[0675] The body 422 defines a lower portion 426 of the sensing and gas flow path. The cover layer 440 has a body 442 that defines an upper portion 446 of the sensing and gas flow path, where the shape of the upper and lower portions 426, 446 substantially correspond to one another.

[0676] As shown in FIG. 14 and FIG. 15 , the gas flow path includes straight elongate gas flow portions 428, 448. The inlet is in fluid communication with tangential inlet portions 430, 450 of the gas flow path, which are at or adjacent to the inlet ends of the straight elongate portions 428, 448 of the gas flow path. Notches 433, 453 and 434, 454 can be provided at opposite ends of the straight elongate portions of the gas flow path.

[0677] The gas flow outlet port 452 extends vertically through the body 442 of the cover layer 440 and is at or adjacent to the opposite outlet ends of the straight elongate portions 428, 448 of the gas flow path. The gas outlet port 452 is in fluid communication with the upper portion of the motor recess 250, which in turn is in fluid communication with the gas flow channel. Again, due to the configuration of the walls 252 and the ceiling 262 of the recess 250, if there is a gas leak from the motor / sensor module 400, the gas will be vented to the atmosphere rather than into the portion of the main housing 100 that contains a large amount of electronics and control equipment. The recess 250 can contain spacers, such as the ledge shown in FIG. 15 extending downwardly from the ceiling 262 to maintain proper spacing for gas flow from the gas outlet port 452 and the ceiling of the recess 262.

[0678] As can be seen in FIG. 14 , at least a portion of the gas flow path through and out of the motor and / or sensing module 400 has a tortuous or serpentine configuration. For example, the direction of gas flow through the elongate portions 428, 448 is generally opposite to the direction of gas flow from the gas outlet port 452 to the inlet of the gas flow channel through the elbow 324.

[0679] As shown in FIG. 14 and FIG. 15As shown, the cover layer 440 includes a sensing printed circuit board (PCB) 456. The cover layer 440 can also include one or more temperature sensors, such as thermistors seated in the elongated portions 428, 448 of the gas flow path. One sensor will measure gas temperature, and another sensor can serve as a redundant temperature sensor. Alternatively, one of the thermistors can serve as a reference flow sensor (e.g., by serving as a constant temperature thermistor), and the measured temperature can be used to determine gas flow through the portions 428, 448 of the gas flow path. The one or more temperature sensors can be located on a portion of the sensing PCB 456 that faces the gas stream. Additionally, the sensing PCB 456 can include other sensors, including but not limited to pressure sensors, humidity sensors, and dew point sensors.

[0680] One or both of the electronic circuit boards 272 will be in electrical communication or coupled with these sensors to process information received from the sensors and operate the device 10 based on information received from the sensors.

[0681] In an alternative configuration, the motor / impeller unit can be disposed away from the device 10. In this configuration, the module received in the recess 250 can include only the gas flow path and various sensors to deliver gas to the fixed elbow 324 and therefrom to the liquid chamber 300. In an alternative configuration, the module received in the recess 250 can include only the motor and the gas flow path, but not the sensors.

[0682] In another alternative configuration, the motor and / or sensor module 400 can not be removable from the recess 250, but can be permanently installed therein. In this configuration, the benefit of isolating the gas from the electrical / electronic components will still be provided.

[0683] The flow path is compact, and has reduced turns / acute turns, which reduces flow separation and lowers flow resistance.

[0684] The arrangement of the motor and flow path provides another layer of isolation due to the wall arrangement.

[0685] Having a modular motor and / or sensor module enables the individual portions of the module to be disassembled if cleaning and / or servicing is required.

[0686] There is advantageously no leak path in the motor and / or sensor module. While the motor and / or sensor module can be a potential leak point, a leak in this area would result in oxygen being vented to the atmosphere or into the liquid chamber.

[0687] FIGS. 17 to FIG. 24A first configuration of the valve module 4001 is shown. The valve module 4001 controls the flow of oxygen and / or other gases into the gas flow path of the device 10 and enables the device 10 to adjust the proportion of oxygen entrained in the air flow. The valve module is formed as a modular unit to facilitate manufacture, assembly, servicing or replacement, for example in the event of a malfunction, routine maintenance or future upgrade / improvement.

[0688] The valve module 4001 is vertically inserted in an upward direction into a valve module receptacle 306 in the lower chassis 202 of the main housing. In alternative configurations, the valve module can be insertable into the housing in a different direction, such as a forward direction, a downward direction, a rearward direction or a side direction. The valve module 4001 is removably engageable with the main housing of the device such that the valve module 4001 is substantially received within the housing and is accessible from the exterior of the housing. In some configurations, the valve module 4001 can be fixed within the main housing and not removable. A portion of the valve module 4001 is arranged to be substantially flush with the exterior wall of the housing when the valve module is removably engaged with the housing.

[0689] As the valve module is modular and accessible from the exterior of the housing, the valve module can be replaced without significant disassembly of the device 10 and without damaging the seals of the housing of the device. As the valve module 4001 is substantially received within the housing, when the valve module is engaged with the housing it becomes integrated with the housing and does not increase the size or bulk of the housing. Additionally, components of the valve module, such as the valve 4003 and valve manifold 4011 described below, are protected in use as they are located within the valve support 4051 and main housing of the device in use. If the device 10 is inadvertently knocked or dropped, this configuration significantly reduces the likelihood of damage to the valve module and valve module components.

[0690] The valve module comprises a flow control valve 4003 arranged to control the flow of gas through the valve manifold 4011. The valve is arranged to control the flow of gas into a portion of the device. For example, the valve can be arranged to control the flow of gas to the filter module 1001. Alternatively, the valve 4003 can be arranged to control the flow of gas to another portion of the device. The valve module 4001 and filter module 1001 are located upstream of the blower 402 and motor and / or sensor module 400. In some embodiments, the valve module 4001 and filter module 1001 are located downstream of the blower 402.

[0691] The valve 4003 comprises a cylindrical body 4005 and a valve member in the body.

[0692] For example, the flow control valve can be a solenoid valve, can be motor driven, or can be piezo electrically operated.

[0693] In the solenoid valve, a valve member is actuated between an open position and a closed position. The solenoid valve can be a proportional valve. The range of gas flow through the valve (i.e., due to the size of the valve opening) is relative to the current supplied to the valve.

[0694] Alternatively, the solenoid valve can be controlled with a modulated input signal to modulate the valve between the open position and the closed position.

[0695] The valve 4003 can be a needle valve, a plunger valve, a gate valve, a globe valve, a butterfly valve, a stop valve, or the like. The valve can be pressure-compensated.

[0696] In some configurations, the valve is a normally closed valve; that is, the valve is closed when de-energized. This will prevent the connected gas supply line from continuously releasing oxygen or other gas when the device is de-energized. In some alternative configurations, the valve is a normally open valve.

[0697] In some configurations, the valve 4003 is an electrically actuated proportional solenoid valve. For example, the valve can be a μProp valve available from Staiger GmbH & Co. KG of Erligheim, Germany, can be an Asco 202 Series Preciflow valve available from Emerson / Asco Valves of New Jersey, or can be any other suitable type of valve.

[0698] The valve can have a coaxial inlet-outlet configuration.

[0699] The valve module 4001 includes a valve manifold 4011 having a body 4013 defining a gas flow path 4015 between a valve manifold gas inlet 4017 and one or more valve manifold gas outlets 4019. The gas inlet 4017 of the valve manifold is positioned axially at or toward an end of the valve manifold. In some configurations, the valve manifold 4011 has a single gas outlet 4019 positioned radially on the valve manifold. In some configurations, the valve manifold 4011 includes multiple valve manifold gas outlets 4019 positioned radially around the valve manifold. The valve manifold outlets 4019 are arranged to deliver gas from the valve manifold gas inlet 4017 to the gas inlet of the filter module 1001. The radial arrangement of the outlet(s) 4019 helps to direct the oxygen (or other gas) toward the filter module, thereby minimizing loss of oxygen and improving entrainment efficiency. The valve 4003 is arranged to control the flow of gas from the valve manifold gas inlet 4017 to the valve manifold gas outlet(s) 4019. When the valve is“closed,” gas flow from the gas inlet 4017 to the gas outlet(s) 4019 is prevented. When the valve is“open,” gas flow from the gas inlet 4017 to the gas outlet(s) 4019 is enabled.

[0700] The end 4018 of the valve manifold 4011 opposite the gas inlet receives and sealingly engages the valve 4003 such that the valve and valve manifold are in fluid communication. The end 4018 includes a flange 4023 to be mounted to the valve. The flange 4023 has apertures 4023A for receiving fasteners 4023F to fasten the manifold to the valve 4003. An O-ring(s) can be provided around the periphery of the interface between the valve 4003 and the valve manifold 4011 to sealingly engage the valve with the valve manifold.

[0701] The valve manifold 4011 directs / disperses the oxygen gas from the valve via a radially positioned gas outlet 4019. In some embodiments, a single gas outlet 4019 is provided in the valve manifold. As the oxygen gas passes through the outlet(s), noise is generated. Because the device can be used in close proximity to a patient in a medical and / or home environment, it is desirable to minimize the noise generated.

[0702] Additionally or alternatively, a shroud, duct or channel can be formed around, near or in fluid communication with the valve manifold outlet 4019 in order to reduce the noise. Additionally or alternatively, a foam or the like can be placed around the valve manifold, near the valve manifold outlet to reduce the noise.

[0703] A small filter can be provided inside the inlet of the valve manifold gas inlet 4017 to prevent dust or particulate from being introduced into the valve.

[0704] The end of the valve manifold corresponding to the gas inlet 4015 is arranged to receive and connect to a connector 4031. In the form shown, the connector 4031 is a rotary connector. Alternatively, the connector 4031 can be arranged such that the gas inlet 4033 of the connector can be moved in a different manner, such as a translational movement or a pivotal movement.

[0705] The valve module 4001 is at the start of the flow path of the device. If the valve 4003 is blocked (i.e. blocked by dust, particulate, etc.) such that it will remain open, then excess pressurized oxygen or other gas will "spill" out of the ambient air inlet opening(s) in the valve support 4051 (e.g. the opening shown below the rotary connector). This will prevent any excess pressure from reaching the patient. As such, the system can inherently be considered to be pressure limited without the need for a pressure relief valve. FIG. 22

[0706] ​The opening(s) 40510 are provided in the valve support 4051 to allow ambient air to be drawn into the gas flow path of the device. The ambient air flow path passes near or close to the valve. In the form shown, the openings 40510 are located around the gas inlet of the rotary connector. Additionally or alternatively, the openings can be located elsewhere in the valve support. When the blower motor 402 of the device is operating, suction will be created through the filter module and the valve module to draw ambient air into the device. The ambient air flow path passes through the valve module and allows ambient air to be entrained by the gas flow from the flow control valve. The ambient air flow path has a gas outlet which is adapted to deliver ambient air so that it flows through one or more temperature sensors of the device which are used to deliver a gas flow.

[0707] The device can draw in gas from the gas inlet of the valve manifold and ambient air simultaneously, or pressurisation of the gas from the gas inlet can force the gas through the filter. The gas will exit the valve module and enter the gas inlet in the filter. The device can be configured so that the gas from the gas inlet and the ambient air are dynamically entrained / mixed in the device before being delivered to the gas outlet of the device.

[0708] The valve module can be configured to minimise the pressure drop across the valve module by one or more of: having large openings 40510 of ambient air located around and / or elsewhere of the rotary connector; having radiused / circular / angled edges in the flow path (i.e. for example inside the valve manifold) to minimise turbulence and smooth flow.

[0709] The valve module 4001 described herein is arranged to couple directly with the filter 1001 to provide a gas flow path from the valve module to the filter. There is no need for a hose connection between the valve module and the filter module. This minimises the size of the components and makes it easy to connect and disconnect the modular valve module and filter module.

[0710] The filter module and valve module described herein can provide varying gas flow paths for the device. For example, the valve module can control the flow of oxygen gas into the device via the valve module and filter module. Alternatively, an alternative oxygen gas source can be connected directly to the filter module, bypassing the valve module, through the first sub-chamber gas inlet (e.g. inlet 1011 of the filter module). This is useful in the event that the user can wish to manually adjust the oxygen gas supply source (i.e. such as by a wall supply rotameter). FIG. 20

[0711] It will be appreciated that the filter module and valve module described herein can be used separately in a device for delivering a gas flow. Alternatively, the filter and valve modules can be used together as a filter and valve assembly to obtain improved functionality. ​

[0712] In the illustrated configuration, the device 10 receives oxygen by at least one of:

[0713] via a valve module (for automatic oxygen regulation of the device), or

[0714] via an alternative gas inlet provided on the top of the filter (allowing attachment of a manually adjustable oxygen supply, i.e. such as by a wall-mounted supply rotary flowmeter).

[0715] The various configurations described are merely example configurations. Any one or more features from any one configuration can be used in combination with any one or more features from any other configuration.

[0716] For example, the rotary connector used in the valve module can have additional functionality. In some configurations, the rotary connector can be arranged to rotate about more than one axis; and may, for example, have two adjacent rotary connection portions with their axes of rotation transverse to one another, so that the gas inlet of the rotary connector can be rotated about both axes. In some configurations, the rotary connector can include a ball-and-socket arrangement or similar, so that the gas inlet of the rotary connector can be rotated in substantially any direction. In some configurations, the rotary connector can be arranged to provide both rotational and translational motion; so that the gas inlet of the rotary connector can be both rotated about one or more axes, and also travel linearly. This can be useful for translating the gas inlet from one portion of the device to another, e.g. from one side of the device to the other. In some configurations, the gas inlet can be arranged to translate rather than rotate.

[0717] As another example, while the motor and / or sensor subassembly recess is described as being in the bottom side of the main housing, it can instead be in the rear, side, front or top of the housing. For such variations, the air and / or oxygen inlets can also be positioned differently as required.

[0718] As another example, instead of the liquid chamber and chamber pocket being configured so that the liquid chamber is inserted into and removed from the chamber pocket from the front of the housing, the configuration can be so that the liquid chamber is inserted into and removed from the chamber pocket from the side, rear or top of the housing.

[0719] As another example, while the filter module is described as being inserted into the housing from above and the valve module is inserted into the housing from below, either or both of these components can be inserted into any suitable portion of the housing, such as an upper portion, lower portion, side portion, front portion or rear portion.

[0720] The filter module and valve module are described with reference to a flow therapy apparatus that is capable of delivering heated and humidified gas to a patient or user. The apparatus can be suitable for treating chronic obstructive pulmonary disease (COPD). The apparatus can be configured to deliver gas to a patient interface at a high flow rate (high flow therapy), in particular nasal high flow therapy.

[0721] Alternatively, the filter module and / or valve module can be used in apparatus for a different purpose. The apparatus can be a high flow therapy apparatus, or can be a low flow therapy apparatus. The features can also be provided in an apparatus for providing continuous positive airway pressure (CPAP), which can deliver gas (humidified or otherwise) at positive pressure.

[0722] Alternatively, the filter module and / or valve module can be used with apparatus that do not require a humidifier and therefore do not require the liquid chamber 300 or chamber pocket 108 features. For example, it will be appreciated that the configuration of isolating the motor and gas flow path from electrical and electronic components has wide application in other types of gas delivery apparatus.

[0723] The language "flow therapy apparatus" is intended to encompass all such variations.

Claims

1. A breathing assistance apparatus comprising: a flow generator configured to provide breathing gases to a patient, the breathing gases comprising supplemental oxygen provided from an oxygen source, a controller configured to control an oxygen concentration of the breathing gases, at least one sensor configured to provide a measurement indicative of a patient blood oxygen concentration to the controller, wherein the controller is configured to determine a target oxygen concentration of the breathing gases, wherein the controller is configured to calculate an estimated future value of the patient blood oxygen concentration based on: a difference between an initial oxygen concentration of the breathing gases and the target oxygen concentration of the breathing gases, and the measurement indicative of the patient blood oxygen concentration.

2. Breathing assistance device according to claim 1, wherein, the controller is configured to control the oxygen concentration of the breathing gases based on the target oxygen concentration.

3. Breathing assistance device according to claim 1 or claim 2, wherein, the estimated future value of the patient blood oxygen concentration is further based on a time since the controller controlling the oxygen concentration of the breathing gases to the target oxygen concentration.

4. The breathing assistance apparatus of any one of claims 1 to 3, wherein, the controller is configured to receive an input and determine the target oxygen concentration of the breathing gases based on the input.

5. Breathing assistance device according to claim 4, wherein the input comprises a target oxygen concentration range, the target oxygen concentration range comprising an upper target oxygen concentration and a lower target oxygen concentration.

6. The breathing assistance apparatus of any one of claims 1 to 5 wherein, the controller is configured to compare the estimated future value of the patient blood oxygen concentration to a blood oxygen concentration alarm range, and generate an alarm output if the estimated future value of the patient blood oxygen concentration is not within the blood oxygen concentration alarm range, and wherein the blood oxygen concentration alarm range comprises an upper blood oxygen concentration alarm threshold and a lower blood oxygen concentration alarm threshold.

7. The breathing assistance apparatus of any one of claims 1 to 6 wherein, the controller is configured to generate an alarm output based on the estimated future value of the patient blood oxygen concentration and a comparison to a blood oxygen concentration alarm threshold; and wherein the controller is configured to generate the alarm output if the estimated future value of the patient blood oxygen concentration is above the upper blood oxygen concentration alarm threshold or below the lower blood oxygen concentration alarm threshold.

8. Breathing assistance device according to claim 6 or claim 7, wherein, the upper blood oxygen concentration alarm threshold and / or lower blood oxygen concentration alarm threshold is determined based on a time since the controller controlling the oxygen concentration of the breathing gases to the target oxygen concentration.

9. The breathing assistance apparatus of any one of claims 6 to 8 wherein, the upper blood oxygen concentration alarm threshold and / or lower blood oxygen concentration alarm threshold is determined based on a change in target oxygen concentration.

10. The breathing assistance apparatus of any one of claims 6 to 8, wherein, the upper blood oxygen concentration alarm threshold and / or lower blood oxygen concentration alarm threshold is determined based on a target oxygen concentration.

11. The breathing assistance apparatus of any one of claims 6 to 10, wherein, the upper blood oxygen concentration alarm threshold and / or lower blood oxygen concentration alarm threshold is determined based on a current gas oxygen concentration.

12. The breathing assistance apparatus of any one of claims 6 to 11 wherein, the upper blood oxygen concentration alarm threshold and / or lower blood oxygen concentration alarm threshold is determined based on the target blood oxygen concentration.

13. The breathing assistance apparatus of any one of claims 6 to 12 wherein, the upper blood oxygen concentration alarm threshold is based on a difference between the target oxygen concentration and an upper target oxygen concentration.

14. The breathing assistance apparatus of any one of claims 1 to 13, wherein, the estimated future value of the patient blood oxygen concentration is based on an oxygen efficiency of the patient and / or a haemoglobin saturation function.

15. The breathing assistance apparatus of claim 14, wherein the oxygen efficiency of the patient is based on the measurement indicative of a patient blood oxygen concentration divided by a measured oxygen concentration of the breathing gases, and / or is received as an input.

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