KR102578530B1 - APPARATUS AND METHOD FOR PERFORMING BILEVEL HIGH FLOW THERAPY BASED ON SpO2 - Google Patents

Abstract

It relates to a high-flow breathing device and method that can adjust the flow rate of mixed gas supplied to a patient based on the patient's blood oxygen saturation, comprising: a breathing pattern monitoring unit that collects the patient's breathing pattern information; a detection unit that detects at least one of an inhalation effort point at which the patient tries to start inhalation and an exhalation effort point at which the patient tries to start exhalation, and based on the inhalation effort point and the exhalation effort point, It includes a supply flow rate control unit that controls the flow rate of the supplied mixed gas, and the supply flow control unit controls the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) when the patient's breathing reaches the inspiratory effort point. The upper flow rate of the mixed gas may be determined based on the target value, and the flow rate of the mixed gas may be increased and supplied according to the determined upper flow rate.

Description

Blood oxygen saturation based high flow breathing apparatus and method {APPARATUS AND METHOD FOR PERFORMING BILEVEL HIGH FLOW THERAPY BASED ON SpO2}

The present invention relates to a high-flow breathing device, and more specifically, to a high-flow breathing device and method that can adjust the flow rate of mixed gas supplied to a patient based on the patient's blood oxygen saturation.

High-flow respiratory therapy refers to the administration of high-concentration heated, humidified air, which is higher than the oxygen concentration in the atmosphere, at a rate 2 to 3 times higher than the patient's respiratory rate, thereby relatively reducing the dead space where gas exchange does not occur, thereby reducing the patient's This refers to treatment that assists breathing.

Generally, most of the air enters the alveoli and gas exchange occurs, and some remains in the respiratory tract. The volume of air remaining in the respiratory tract is called dead space. No gas exchange occurs in the dead space during actual breathing.

For example, when a normal person's tidal volume is 500ml and the dead space volume is about 150ml, the actual respiratory volume is 350ml. However, patients whose breathing capacity is poor and whose tidal volume is only 300 ml have a respiratory volume that is less than 1/2 of the normal level because the actual respiratory volume is 150 ml excluding 150 ml of dead space. Likewise, if the patient's respiratory volume is not sufficiently greater than the dead space, respiratory failure (shortness of breath) occurs in the patient.

Therefore, the patient breathes faster or consumes a lot of energy to maintain normal oxygen saturation, which further worsens the patient's condition.

To solve this problem, conventional methods have been used to introduce a high-flow respiratory therapy device and administer a constant oxygen flow rate to the patient. The administration method can be done using a nasal cannula, which is a thin tube inserted into both nostrils and hung over the ears, or an oxygen mask.

However, existing high-flow respiratory therapy devices have the problem of not reducing the burden on the patient's inhalation or exhalation efforts because they administer mixed gases at the same flow rate regardless of the inhalation and exhalation timing, which may vary depending on the patient's condition. there was.

Therefore, in the future, there is a demand for the development of a high-flow breathing device that can reduce the patient's inhalation or exhalation effort by adjusting the flow rate of the mixed gas according to the patient's condition in consideration of the patient's inhalation and exhalation timing.

Republic of Korea Patent Publication No. 10-1333195 (November 20, 2013)

The technical problem to be achieved by one embodiment of the present invention is to reduce the patient's inspiratory effort by controlling the flow rate of the mixed gas based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point. The object is to provide a flow breathing device and method.

In addition, the present invention provides medical staff convenience and improves the patient's diagnostic accuracy by automatically controlling the inhaled oxygen concentration based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point. The object is to provide a flow breathing device and method.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

In order to solve the above technical problem, a high-flow breathing device according to an embodiment of the present invention includes a breathing pattern monitoring unit that collects the patient's breathing pattern information, and a breathing pattern monitoring unit that collects the patient's breathing pattern information, and allows the patient to start inhalation from the patient's breathing pattern information. a detector for detecting at least one of an intake effort point at which the patient tries to start exhaustion and an exhaust effort point at which the patient tries to start exhaustion, and a flow rate of mixed gas supplied to the patient based on the intake effort point and the exhaust effort point. A memory unit storing a data table containing the fraction of inspired oxygen (FiO ₂ ) value for the patient's blood oxygen saturation (Saturation of partial pressure oxygen (SpO ₂ )), including a supply flow rate control unit that regulates the ; further comprising; wherein the detection unit extracts a maximum intake effort point at which the change in intake flow rate is maximum and an exhaust effort stop point at which breathing briefly stops before re-inhalation after exhaustion, and the extracted exhaust effort stop point Referring to the maximum inspiration effort point, the point in time at which the patient starts the inspiratory effort is detected as the inspiratory effort point, and the supply flow rate control unit detects the patient's blood oxygen when the patient's breathing reaches the inspiratory effort point. The upper flow rate of the mixed gas is determined based on the saturation (Saturation of partial pressure oxygen, SpO ₂ ) target value, and the flow rate of the mixed gas is increased and supplied according to the determined upper flow rate, but the patient's blood oxygen saturation target The patient's inhaled oxygen concentration corresponding to the value may be extracted from the data table stored in the memory unit, and the flow rate of the mixed gas may be increased and supplied to achieve the extracted inhaled oxygen concentration.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller may set the target blood oxygen saturation value of the patient in the range of 80% to 99%.

In an alternative embodiment of the high-flow breathing apparatus, the blood oxygen saturation target value may be set based on patient information including at least one of the patient's age group, gender, and physical condition.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller may increase the upper flow rate limit of the mixed gas when the target blood oxygen saturation value of the patient decreases.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller, when increasing the flow rate of the mixed gas, adjusts the fraction of inspired oxygen of the mixed gas corresponding to the target blood oxygen saturation value of the patient. , FiO ₂ ) can be varied.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller may increase the inhaled oxygen concentration of the mixed gas when the target blood oxygen saturation value of the patient decreases.

In an alternative embodiment of the high-flow breathing apparatus, the device further includes a memory unit storing a data table containing inhaled oxygen concentration values for the blood oxygen saturation, and the supply flow rate controller is configured to vary the inhaled oxygen concentration of the mixed gas. When the target blood oxygen saturation value of the patient varies, the inspired oxygen concentration value of the mixed gas can be varied by extracting the inspired oxygen concentration value for the varied blood oxygen saturation from the data table.

In an alternative embodiment of the high flow breathing device, the inhaled oxygen concentration of the mixed gas may have a lower limit of 21% to 96% and an upper limit of 25% to 100%.

In an alternative embodiment of a high-flow breathing apparatus, the lower and upper limits of inspired oxygen concentration may satisfy the relationship: lower limit of inspired oxygen concentration ≤ (upper limit of inspired oxygen concentration - 4).

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller may determine the inhaled oxygen concentration of the mixed gas as a preset inhaled oxygen concentration value when increasing the flow rate of the mixed gas.

In an alternative embodiment of the high flow breathing apparatus, the preset inspired oxygen concentration value may be about 60%.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate control unit, when increasing the flow rate of the mixed gas, supplies the mixed gas at a basal flow rate when the patient starts breathing, and then supplies the mixed gas at a basal flow rate when the patient starts breathing. When breathing reaches the inspiratory effort point, an auxiliary flow rate (flow assist) can be further increased in addition to the basic flow rate.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller may supply the mixed gas by reducing the flow rate when the patient's breathing reaches the exhaust effort point.

In an alternative embodiment of the high-flow breathing device, the supply flow rate controller reduces the flow rate of the mixed gas when the patient's breathing reaches the exhaust effort point. It can be reduced by the auxiliary flow rate.

In an alternative embodiment of the high-flow breathing apparatus, the supply flow rate controller reduces the flow rate of the mixed gas when the patient's breathing reaches the exhaust effort point and exhausts the mixed gas at the supply flow rate comprising the base flow rate. It can be reduced by flow assist.

In an alternative embodiment of a high flow breathing device, the supply flow controller may reduce the exhaust auxiliary flow rate by the amount and then increase the supply flow rate to the base flow rate in proportion to the reduction in exhaust effort.

In an alternative embodiment of the high-flow breathing device, it further includes a breathing synchronization unit that synchronizes the detected inhalation effort point and the exhalation effort point with the patient's breathing pattern information, and the supply flow rate control unit is configured to: The flow rate control of the mixed gas can be performed in synchronization with respect to the synchronized intake effort point and the exhaust effort point.

In an alternative embodiment of the high-flow breathing apparatus, the detection unit includes an inspiratory effort point detection unit that detects an inspiratory effort point at which the patient tries to start inspiration from the breathing pattern information of the patient, and It may include an exhaust effort point detection unit that detects an exhaust effort point at which the patient tries to start exhaustion.

In an alternative embodiment of the high-flow breathing apparatus, the inspiratory effort point detection unit detects, in the breathing pattern information of the patient, the inspiratory maximum effort point where the change in inspiratory flow rate is maximum, and where breathing briefly stops before inhaling again after exhalation. Each exhaust effort stop point can be extracted, and the inspiratory effort point at which the patient starts the inspiratory effort can be detected between them by referring to the extracted exhaust effort stop point and the inspiratory maximum effort point.

In an alternative embodiment of the high-flow breathing apparatus, the exhaust effort point detector detects, in the breathing pattern information of the patient, an exhaust maximum effort point at which the change in the patient's exhaust flow rate is maximum, and a breathing before inspiration after completion of the exhaust. Each exhaust effort stop point that briefly stops can be extracted, and the exhaust effort point at which the patient starts the exhaust effort can be detected between them by referring to the extracted maximum exhaust effort point and the exhaust effort stop point.

Meanwhile, a method of controlling a high-flow breathing apparatus according to an embodiment of the present invention includes a breathing pattern monitoring unit, a detection unit, a supply flow rate control unit, and a memory unit, wherein the breathing pattern monitoring unit includes, Collecting information on the patient's breathing pattern; detecting, by the detection unit, at least one of an inhalation effort point at which the patient tries to start inhalation and an exhalation effort point at which the patient tries to start exhalation from the breathing pattern information of the patient; Confirming, by the supply flow rate control unit, whether the patient's breathing reaches the inspiratory effort point; determining, by the supply flow rate control unit, an upper limit value of the flow rate of the mixed gas supplied to the patient based on the target blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) of the patient when the inspiration effort point is reached; When the supply flow control unit reaches the inspiration effort point, the patient's inspired oxygen concentration (Fraction of inspired oxygen, FiO ₂ ) corresponding to the target blood oxygen saturation value of the patient is extracted and determined from the data table stored in the memory unit. step; The supply flow rate controller increases and supplies the flow rate of the mixed gas according to the determined upper limit of the flow rate of the mixed gas, and increases the flow rate of the mixed gas to reach the determined intake oxygen concentration. In the step of detecting the inspiratory effort point, the detector extracts the maximum inspiratory effort point at which the change in inspiratory flow rate is maximum and the expiratory effort stop point at which breathing briefly stops before re-inhalation after exhalation, and Referring to the extracted exhaust effort stop point and the inspiration maximum effort point, the point at which the patient starts the intake effort is detected as the intake effort point, and the step of increasing the flow rate of the mixed gas includes the supply flow rate control unit, When the target value of blood oxygen saturation of the patient decreases, the upper limit value of the flow rate of the mixed gas is increased to reduce the patient's inspiratory effort, and when the flow rate of the mixed gas is increased, corresponding to the target value of blood oxygen saturation of the patient The inhaled oxygen concentration of the mixed gas can be varied, and when the inhaled oxygen concentration of the mixed gas is varied, if the target blood oxygen saturation value of the patient varies, the varied blood oxygen saturation is calculated from the data table stored in the memory unit. The intake oxygen concentration value for is extracted to vary the intake oxygen concentration of the mixed gas.

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In an alternative embodiment of a method of controlling a high-flow breathing apparatus, varying the inhaled oxygen concentration of the mixed gas may include increasing the inhaled oxygen concentration of the mixed gas when the target blood oxygen saturation value of the patient decreases. .

The effects of the high-flow breathing apparatus and method according to the present invention will be described as follows.

The present invention can reduce the patient's inspiratory effort by controlling the flow rate of the mixed gas based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention can provide convenience to medical staff and improve the accuracy of the patient's diagnosis by automatically controlling the inhaled oxygen concentration based on the target blood oxygen saturation value of the patient when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention reduces dead space clinically by supplying a high flow rate of mixed gas sufficient to ventilate the patient's nasal cavity with fresh air when the patient inhales, and reduces the effort of exhalation breathing when the patient exhales. This may reduce the patient's respiratory effort.

Further scope of applicability of the present invention will become apparent from the detailed description that follows. However, since various changes and modifications within the spirit and scope of the present invention may be clearly understood by those skilled in the art, the detailed description and specific embodiments such as preferred embodiments of the present invention should be understood as being given only as examples.

1 is a block diagram illustrating a high-flow breathing apparatus according to the present invention.
Figure 2 is a flowchart for explaining a control method of a high-flow breathing apparatus according to an embodiment of the present invention.
Figure 3 is a flowchart for explaining a control method of a high-flow breathing apparatus according to another embodiment of the present invention.
Figure 4 is a graph for explaining the process of automatically controlling the intake oxygen concentration of the high-flow breathing apparatus according to the present invention.
Figures 5 and 6 are graphs showing monitoring values for changes in flow rate of mixed gas.
Figures 7 and 8 are waveform diagrams showing an example of extracting a patient's inhalation effort point and exhaustion effort point according to changes in the patient's breathing.
Figure 9 is a diagram for explaining the high-flow breathing apparatus of the present invention applied to a patient's breathing apparatus.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The suffixes “module” and “part” for the components used in the following description are simply given in consideration of the ease of writing this specification, and the “module” and “part” may be used interchangeably.

Furthermore, embodiments of the present invention will be described in detail below with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terms used in this specification are general terms that are currently widely used as much as possible while considering the function in the present invention, but this may vary depending on the intention or custom of a person skilled in the art or the emergence of new technology. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in the description of the relevant invention. Therefore, we would like to clarify that the terms used in this specification should be interpreted based on the actual meaning of the term and the overall content of this specification, not just the name of the term.

1 is a block diagram illustrating a high-flow breathing apparatus according to the present invention.

As shown in Figure 1, the high-flow breathing device 500 of the present invention includes a breathing pattern monitoring unit 510 that collects the patient's breathing pattern information, and a breathing pattern monitoring unit 510 that allows the patient to try to start inspiration from the patient's breathing pattern information. A detection unit 520 that detects at least one of the intake effort point and the exhaust effort point at which the patient tries to start exhaustion, and a supply that adjusts the flow rate of the mixed gas supplied to the patient based on the intake effort point and the exhaust effort point. It may include a flow rate control unit 530.

In addition, the present invention includes a memory unit 540 that stores a data table containing the inspired oxygen concentration value for blood oxygen saturation, and a breathing synchronization unit that synchronizes the inspiratory effort point and the exhalation effort point detected with the patient's breathing pattern information. More may be included.

The supply flow rate controller 530 of the present invention determines the upper limit of the flow rate of the mixed gas based on the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) target value when the patient's breathing reaches the inspiration effort point. And, the flow rate of the mixed gas can be increased and supplied according to the determined upper limit of the flow rate.

As an example, the supply flow controller 530 may set the target blood oxygen saturation value of the patient in the range of about 80% to about 99%, but is not limited thereto.

Here, the target blood oxygen saturation value of the patient is the blood oxygen saturation targeted through the patient's oxygen treatment, and is preferably set in the range of about 80% to about 99%.

Additionally, the blood oxygen saturation target value may be set based on patient information including at least one of the patient's age group, gender, and physical condition, but is not limited thereto.

In the present invention, blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) refers to the amount of oxygen bound to hemoglobin in the blood, which represents the amount of oxygen transported by red blood cells.

In other words, the measurement value of blood oxygen saturation is a measurement value that indicates how effectively the patient breathes, and the measurement value can be expressed as a percentage.

In general, normal measurements of blood oxygen saturation may be, but are not limited to, about 97% to about 99% for adults and about 94% to about 98% for children.

Additionally, blood oxygen saturation can be measured using a pulse oximeter (pulse oximeter), which consists of a computerized monitor and detector, and can be measured by attaching the pulse oximeter to the patient's fingers, toes, or earlobes.

Therefore, in the present invention, when setting the blood oxygen saturation target value, it is necessary to set it by considering various patient information such as the patient's age, gender, physical condition, etc.

Additionally, the supply flow rate controller 530 may monitor the patient's blood oxygen saturation and increase the upper limit of the flow rate of the mixed gas when the patient's blood oxygen saturation target value decreases.

The reason is that the patient's inspiratory effort can be reduced by increasing the upper limit of the flow rate of the mixed gas.

As such, the present invention can reduce the patient's inspiratory effort by controlling the flow rate of the mixed gas based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point.

Additionally, when increasing the flow rate of the mixed gas, the supply flow controller 530 may vary the fraction of inspired oxygen (FiO ₂ ) of the mixed gas in accordance with the target blood oxygen saturation value of the patient.

Generally, the inspired oxygen concentration refers to the oxygen concentration during the patient's inspiration. It represents the concentration of oxygen contained in the air when the patient breathes in, and can be expressed as a percentage.

For example, during oxygen treatment, if the concentration of inhaled oxygen supplied to the patient is high, the patient may be exposed to O2 toxicity and may cause lung disorders.

Additionally, if the concentration of inhaled oxygen supplied to the patient is low, there is a risk that the patient may be exposed to hypoxia.

The supply flow rate controller 530 of the present invention can increase the inhaled oxygen concentration of the mixed gas when the target blood oxygen saturation value of the patient decreases.

As such, the present invention can provide convenience to medical staff and improve diagnostic accuracy of the patient by automatically controlling the inhaled oxygen concentration based on the target blood oxygen saturation value of the patient when the patient's breathing reaches the inspiratory effort point.

As an embodiment, when changing the inhaled oxygen concentration of the mixed gas, the supply flow control unit 530 of the present invention changes the blood oxygen saturation target value of the patient from the data table stored in the memory unit 540. By extracting the intake oxygen concentration value for oxygen saturation, the intake oxygen concentration of the mixed gas can be varied.

Here, the range of the variable inhaled oxygen concentration of the mixed gas may have a lower limit of about 21% to about 96% and an upper limit of about 25% to about 100%.

For example, the lower and upper limits of the inspired oxygen concentration are preferably set to maintain a difference of at least about 4%.

That is, it is desirable that the lower limit and upper limit of the inhaled oxygen concentration satisfy the relational expression: lower limit of the inhaled oxygen concentration ≤ (upper limit of the inhaled oxygen concentration - 4).

As another embodiment, the supply flow rate controller 530 of the present invention may determine the intake oxygen concentration of the mixed gas using a preset intake oxygen concentration value when increasing the flow rate of the mixed gas.

Here, the preset intake oxygen concentration value is preferably about 60%.

Next, when increasing the flow rate of the mixed gas, the supply flow control unit 530 of the present invention supplies the mixed gas at the basal flow rate when the patient's breathing begins, and then when the patient's breathing reaches the inspiratory effort point. Then, the basic flow rate can be supplied by increasing the auxiliary flow rate (flow assist).

Here, the basic flow rate may include a flow rate at a level that can ventilate the patient's nasal cavity with fresh air and the patient's maximum intake flow rate.

At this time, the patient's maximum inspiratory flow rate can be calculated as 3 to 4 times the respiratory volume per minute.

And, the flow rate at a level that can ventilate the patient's nasal cavity with fresh air can be determined in accordance with clinical or anatomical criteria.

Subsequently, the auxiliary flow rate may be determined based on at least one of the patient's condition, the patient's breathing size, and the cannula's installation condition, but is not limited thereto.

Therefore, the present invention can clinically reduce dead space and reduce the patient's breathing effort by supplying mixed gas at a high flow rate sufficient to ventilate the patient's nasal cavity with fresh air when the patient inhales.

In addition, the supply flow rate controller 530 of the present invention can supply the mixed gas by reducing the flow rate when the patient's breathing reaches the exhaustion effort point.

That is, when reducing the flow rate of the mixed gas, the supply flow control unit 530 may reduce the supply flow rate of the mixed gas including the basic flow rate and the auxiliary flow rate by the auxiliary flow rate when the patient's breathing reaches the exhaust effort point.

Here, the basic flow rate may include a flow rate at a level that can ventilate the patient's nasal cavity with fresh air and the patient's maximum intake flow rate.

At this time, the patient's maximum inspiratory flow rate can be calculated as 3 to 4 times the respiratory volume per minute.

And, the flow rate at a level that can ventilate the patient's nasal cavity with fresh air can be determined in accordance with clinical or anatomical criteria.

Therefore, the present invention reduces the exhaust breathing effort by reducing the supply flow rate of the mixed gas by the auxiliary flow rate when the patient is exhausted, thereby reducing the patient's breathing effort.

In addition, when reducing the flow rate of the mixed gas, the supply flow control unit 530 of the present invention provides an exhaust assist flow rate (flow assist) at the supply flow rate of the mixed gas including the basic flow rate when the patient's breathing reaches the exhaust effort point. It can also be reduced by as much.

Additionally, the supply flow rate controller 530 may reduce the exhaust auxiliary flow rate and then increase the supply flow rate to the basic flow rate in proportion to the decrease in exhaust effort.

That is, the supply flow control unit 530 maintains the supply at a set basic flow rate when the patient starts breathing, and when the exhaust effort point is reached, reduces the flow rate of the mixed gas by the exhaust auxiliary flow rate and then supplies it at the exhaust flow rate, thereby exhausting the patient. It can reduce your effort.

Thereafter, when the patient's exhaustion effort decreases, the supply flow rate controller 530 increases the flow rate in proportion to the decrease in exhaustion effort, and when it increases to the basic flow rate, it can maintain the basic flow rate until the next exhaustion effort point is detected.

Here, the basic flow rate may be set to include a flow rate at a level that can ventilate the patient's nasal cavity with fresh air and the patient's maximum intake flow rate.

At this time, the patient's maximum inspiratory flow rate can be clinically determined to be 3 to 4 times the respiratory volume per minute, and the respiratory volume per minute can be calculated as tidal volume × respiratory rate per minute.

For example, assuming that an adult's respiratory volume per tidal volume is about 500 ml and the average number of breaths per minute is about 14, the respiratory volume per minute is approximately 7 L/min, and accordingly, the maximum inspiratory flow rate can be determined to be about 20 LPM to about 30 LPM. there is.

In this way, the flow rate at a level that fills the nasal cavity with fresh air and the patient's maximum inspiratory flow rate can be determined based on clinical or anatomical criteria.

Next, the present invention may further include a breathing synchronization unit 550 that synchronizes the inhalation effort point and the exhalation effort point detected with the patient's breathing pattern information, respectively.

That is, the breathing synchronization unit 550 can synchronize the intake and exhaust timing with the patient's breathing cycle.

Here, the supply flow rate control unit 530 may synchronize the flow rate control of the mixed gas with respect to the intake effort point and the exhaust effort point synchronized in the respiration synchronization unit 550.

That is, the supply flow rate controller 530 increases the flow rate of the mixed gas by synchronizing at this point when it reaches the inhalation effort point in the patient's breathing cycle, and decreases the flow rate of the mixed gas by synchronizing at this point when it reaches the exhaust effort point. You can.

Meanwhile, the breathing pattern monitoring unit 510 of the present invention can collect the patient's breathing pattern information by monitoring the flow rate change and pressure change of the mixed gas supplied to the patient.

As an example, the breathing pattern monitoring unit 510 may collect the patient's breathing pattern information including flow rate and pressure information from the flow sensor and the pressure sensor, but is not limited to this.

In addition, the detection unit 520 of the present invention includes an inhalation effort point detection unit 522 that detects the inhalation effort point at which the patient tries to start inspiration from the patient's breathing pattern information, and an inhalation effort point detection unit 522 that detects the patient's exhaustion from the patient's breathing pattern information. It may include an exhaust effort point detection unit 524 that detects an exhaust effort point trying to start.

Here, the inspiratory effort point detector 522 extracts, from the patient's breathing pattern information, the maximum inspiratory effort point where the change in inspiratory flow rate is maximum and the exhaled effort stop point where breathing briefly stops before re-inhaling after exhaling, , the inspiratory effort point at which the patient starts the inspiratory effort can be detected between the extracted exhalation effort stop point and the inspiratory maximum effort point.

At this time, the intake effort point detection unit 522 detects the exhaust effort stop point from the average value of adding the patient's respiratory flow rate during one cycle and dividing it by the number, and sets the exhaust effort stop point as zero to determine the maximum intake effort point and the maximum exhaust effort point. You can extract where it is located relatively.

In addition, the intake effort point detector 522 calculates a scalar value between the exhaust effort stop point in the first cycle and the intake maximum effort point in the second cycle with reference to at least two cycles, and the calculated scalar value Based on , a value corresponding to a certain range of about 10% to about 30% from the maximum inspiration effort point can be detected as the inspiration effort point.

In some cases, the intake effort point detector 522 may calculate the slope between the exhaust effort stop point in the first cycle and the maximum intake effort point in the second cycle and detect the intake effort point based on the calculated slope. .

Here, the range from about 10% to about 30% may be set differently depending on the patient's condition, the cannula's installation condition, etc.

Then, the effort point and stopping point can be calculated in relation to the equation below.

Effort = Pressure × Volume/time = Pressure × Flow(L/min)

In addition, the exhaust effort point detection unit 524 extracts, from the patient's breathing pattern information, the maximum exhaust effort point at which the change in the patient's exhaust flow rate is maximum and the exhaust effort stop point at which breathing stops briefly before inspiration after completion of exhaustion. And, by referring to the extracted maximum exhaust effort point and the exhaust effort stop point, the exhaust effort point at which the patient starts the exhaust effort can be detected between them.

Here, the exhaust effort break point can be extracted from the average value of the patient's respiratory flow rate added during one cycle divided by the number.

The exhaust effort point detector 524 can extract where the maximum exhaust effort point is located relative to the exhaust effort stop point as zero.

In addition, the exhaust effort point detector 524 calculates a scalar value between the exhaust effort stop point in the first cycle and the maximum exhaust effort point in the second cycle with reference to at least two cycles, and calculates the calculated scalar value. Based on , a value corresponding to a certain range of about 10% to about 30% or less from the maximum exhaust effort point can be detected as the exhaust effort point.

In some cases, the slope between the exhaust effort stop point in the first cycle and the maximum exhaust effort point in the second cycle may be calculated, and the exhaust effort point may be detected based on the calculated slope.

In addition, the detected intake effort points and exhaust effort points may temporally correspond to a point before the respective maximum intake effort points and maximum exhaust effort points.

Therefore, if the flow rate is controlled and supplied at the intake effort point and the exhaustion effort point, the patient's intake or exhaustion effort can be effectively reduced when the patient is maximally inhaling or exhaling.

As such, the present invention can reduce the patient's inspiratory effort by controlling the flow rate of the mixed gas based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention can provide convenience to medical staff and improve the accuracy of the patient's diagnosis by automatically controlling the inhaled oxygen concentration based on the target blood oxygen saturation value of the patient when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention reduces dead space clinically by supplying a high flow rate of mixed gas sufficient to ventilate the patient's nasal cavity with fresh air when the patient inhales, and reduces the effort of exhalation breathing when the patient exhales. This may reduce the patient's respiratory effort.

Figure 2 is a flowchart for explaining a control method of a high-flow breathing apparatus according to an embodiment of the present invention.

As shown in Figure 2, first, the present invention can collect the patient's breathing pattern information (S10).

Here, the present invention can collect information on the patient's breathing pattern by monitoring changes in the flow rate and pressure of the mixed gas supplied to the patient.

Next, the present invention can detect at least one of the inhalation effort point at which the patient tries to start inhalation and the exhalation effort point at which the patient tries to start exhalation from the patient's breathing pattern information (S20).

Here, the present invention extracts, from the patient's breathing pattern information, the maximum inspiration effort point where the change in inspiration flow rate is maximum and the exhaust effort stop point where breathing briefly stops before re-inhalation after exhaustion, and the extracted exhaust effort By referring to the rest point and the maximum inspiration effort point, the inspiratory effort point at which the patient starts the inspiratory effort can be detected between them.

In addition, the present invention extracts, from the patient's breathing pattern information, the maximum exhaust effort point where the change in the patient's exhaust flow rate is maximum and the exhaust effort stop point where breathing stops briefly before inspiration after completion of exhaust, and the extracted exhaust By referring to the maximum effort point and the exhaustion effort stop point, the exhaustion effort point at which the patient starts exhaustion effort can be detected between them.

Next, the present invention can confirm whether the patient's breathing reaches the inspiration effort point (S30).

In addition, in the present invention, when the inspiration effort point is reached, the upper limit value of the flow rate of the mixed gas can be determined based on the target value of the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) (S40).

Here, the present invention can increase the upper limit value of the flow rate of the mixed gas when the target value of blood oxygen saturation of the patient decreases.

Next, the present invention can determine the fraction of inspired oxygen (FiO ₂ ) of the mixed gas in accordance with the target blood oxygen saturation value of the patient (S50).

Here, the present invention can increase the inhaled oxygen concentration of the mixed gas when the target blood oxygen saturation value of the patient decreases.

For example, in the present invention, if the target blood oxygen saturation value of a patient varies, the inspired oxygen concentration value of the mixed gas can be varied by extracting the inspired oxygen concentration value for the varied blood oxygen saturation from a pre-stored data table.

At this time, the range of the variable intake oxygen concentration may have a lower limit of about 21% to about 96% and an upper limit of about 25% to about 100%.

The lower limit and upper limit of the inhaled oxygen concentration may be satisfied by the following relational expression: lower limit of the inhaled oxygen concentration ≤ (upper limit of the inhaled oxygen concentration - 4).

Next, the present invention can supply the mixed gas by increasing the flow rate to the determined upper flow rate and intake oxygen concentration (S60).

Here, in the present invention, when the patient's breathing begins, the mixed gas can be supplied at a basic flow rate, and when the patient's breathing reaches the inhalation effort point, the auxiliary flow rate can be further increased and supplied to the basic flow rate.

At this time, the basic flow rate may include a flow rate at a level that can ventilate the patient's nasal cavity with fresh air and the patient's maximum inspiratory flow rate, and the auxiliary flow rate may include the patient's condition, the patient's breathing size, and the cannula installation state. It can be decided based on at least one thing.

And, the present invention can check whether the patient's breathing reaches the exhaust effort point (S70).

Next, in the present invention, when the exhaust effort point is reached, the flow rate of the mixed gas can be reduced and supplied (S80).

Here, in the present invention, when the patient's breathing reaches the exhaust effort point, the supply flow rate of the mixed gas including the basic flow rate and the auxiliary flow rate can be reduced by the auxiliary flow rate.

At this time, the basic flow rate may include a flow rate at a level that can ventilate the patient's nasal cavity with fresh air and the patient's maximum intake flow rate.

In some cases, the present invention may reduce the supply flow rate of the mixed gas including the basic flow rate by the exhaust auxiliary flow rate when the patient's breathing reaches the exhaust effort point.

And, in the present invention, after reducing the exhaust auxiliary flow rate, the supply flow rate can be increased to the basic flow rate in proportion to the reduction in exhaust effort.

Next, the present invention checks whether there is a user input to end supply flow rate control (S90), and when a user input to end supply flow rate control is received, supply flow rate control can be terminated.

Figure 3 is a flowchart for explaining a control method of a high-flow breathing apparatus according to another embodiment of the present invention.

As shown in Figure 3, first, the present invention can collect information on the patient's breathing pattern (S110).

Next, the present invention can detect at least one of the inhalation effort point at which the patient tries to start inhalation and the exhalation effort point at which the patient tries to start exhalation from the patient's breathing pattern information (S120).

Next, the present invention can confirm whether the patient's breathing reaches the inspiration effort point (S130).

In addition, in the present invention, when the inspiration effort point is reached, the upper limit value of the flow rate of the mixed gas can be determined based on the target value of the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) (S140).

Next, the present invention can determine the fraction of inspired oxygen (FiO ₂ ) of the mixed gas using a preset inspired oxygen concentration value (S150).

Here, the preset intake oxygen concentration value may be about 60%.

Next, the present invention can supply the mixed gas by increasing the flow rate to the determined upper flow rate and intake oxygen concentration (S160).

Here, in the present invention, when the patient's breathing begins, the mixed gas can be supplied at a basic flow rate, and when the patient's breathing reaches the inhalation effort point, the auxiliary flow rate can be further increased and supplied to the basic flow rate.

And, the present invention can check whether the patient's breathing reaches the exhaust effort point (S170).

Next, in the present invention, when the exhaust effort point is reached, the flow rate of the mixed gas can be reduced and supplied (S180).

Here, in the present invention, when the patient's breathing reaches the exhaust effort point, the supply flow rate of the mixed gas including the basic flow rate and the auxiliary flow rate can be reduced by the auxiliary flow rate.

In some cases, the present invention may reduce the supply flow rate of the mixed gas including the basic flow rate by the exhaust auxiliary flow rate when the patient's breathing reaches the exhaust effort point.

In addition, the present invention checks whether there is a user input to end supply flow rate control (S190), and when a user input to end supply flow rate control is received, supply flow rate control can be terminated.

Figure 4 is a graph for explaining the process of automatically controlling the intake oxygen concentration of the high-flow breathing apparatus according to the present invention.

The present invention can determine the fraction of inspired oxygen (FiO ₂ ) of the mixed gas in accordance with the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) target value.

Here, the present invention can increase the inhaled oxygen concentration of the mixed gas when the target blood oxygen saturation value of the patient decreases.

For example, as shown in FIG. 4, the target blood oxygen saturation (SpO ₂ ) can be set to about 95%, the upper limit of the inspired oxygen concentration (FiO 2 ) is about 65%, and the inspired oxygen concentration (FiO ₂ ) can be set to about 95%. The lower limit of FiO ₂ ) can be set to about 40%.

Additionally, the preset value of the inspired oxygen concentration (FiO ₂ ) can be set to about 60%.

As such, the present invention supplies mixed gas to the patient by automatically controlling the inspired oxygen concentration (FiO ₂ ) in real time in accordance with the blood oxygen saturation (SpO ₂ ) target value, thereby providing convenience to medical staff and improving the accuracy of the patient's diagnosis. can be improved.

In Figure 4, section A is a section where the blood oxygen saturation (SpO ₂ ) measured value is lower than the target value, and the supply flow rate controller of the present invention controls the intake oxygen within the range of the upper and lower limits of the intake oxygen concentration (FiO ₂ ). Concentration (FiO ₂ ) can be increased.

Here, the blood oxygen saturation (SpO ₂ ) measurement value can be measured every 30 seconds.

And, section B is a section where the blood oxygen saturation (SpO ₂ ) measured value is higher than the target value, and the supply flow rate control unit of the present invention controls the intake oxygen concentration (FiO _{2 ) within the range of the upper and lower limits of the intake oxygen concentration (FiO 2} ). FiO ₂ ) can be reduced.

Next, section C is a section in which there is no blood oxygen saturation (SpO ₂ ) measurement value, and the supply flow rate controller of the present invention can be set to about 60%, which is the preset inspired oxygen concentration (FiO ₂ ).

Next, section D is a section where the blood oxygen saturation (SpO ₂ ) measured value is the same as the target value, and the supply flow rate controller of the present invention controls the intake oxygen concentration (FiO ₂ ) within the range of the upper and lower limits of the intake oxygen concentration (FiO 2 ). FiO ₂ ) can be maintained as is.

Figures 5 and 6 are graphs showing monitoring values for changes in flow rate of mixed gas.

As shown in FIG. 5, the present invention sets the target blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) of the patient when the patient reaches the inspiratory effort point at which the patient tries to start inspiration based on the patient's breathing pattern information. Based on this, the upper limit of the flow rate of the mixed gas and the intake oxygen concentration (Fraction of inspired oxygen, FiO ₂ ) of the mixed gas are determined, and the flow rate of the mixed gas can be increased and supplied by the determined upper limit of the flow rate and the intake oxygen concentration.

Here, in the present invention, when the patient's breathing begins, the mixed gas can be supplied at a basic flow rate, and when the patient's breathing reaches the inhalation effort point, the auxiliary flow rate can be further increased and supplied to the basic flow rate.

In addition, according to the present invention, when the exhaust effort point at which the patient tries to start inhalation is reached, the supply flow rate of the mixed gas including the basic flow rate and the auxiliary flow rate can be reduced by the auxiliary flow rate and supplied.

In addition, as shown in FIG. 6, the present invention can reduce the supply flow rate of the mixed gas including the basic flow rate by the exhaust auxiliary flow rate when the patient's breathing reaches the exhaust effort point.

And, in the present invention, after reducing the exhaust auxiliary flow rate, the supply flow rate can be increased to the basic flow rate in proportion to the reduction in exhaust effort.

Figures 7 and 8 are waveform diagrams showing an example of extracting a patient's inhalation effort point and exhaustion effort point according to changes in the patient's breathing.

As shown in Figures 7 and 8, the present invention provides an inspiratory effort point (A) at which the patient tries to start inhalation from the patient's breathing pattern information, and an inspiratory effort point (A) at which the patient tries to start exhalation from the patient's breathing pattern information. The exhaust effort point (B) can be detected.

That is, the inspiratory effort point detection unit of the present invention detects, from the patient's breathing pattern information, the inspiratory maximum effort point (C) where the change in inspiratory flow rate is maximum and the exhalation effort stop point (C) where breathing stops briefly before re-inhaling after exhaling E) can be extracted respectively, and the inspiratory effort point (A) at which the patient starts the inspiratory effort can be detected between them by referring to the extracted exhalation effort stop point (E) and the inspiratory maximum effort point (C).

At this time, the inspiratory effort point detector of the present invention detects the exhaust effort stop point (E) from the average value of adding the patient's respiratory flow rate during one cycle and dividing it by the number, and sets the exhaust effort stop point (E) to zero as the maximum inspiratory effort. It is possible to extract where the point (C) and the exhaust maximum effort point (D) are located relatively.

In addition, the intake effort point detector of the present invention refers to at least two cycles and calculates a scalar value between the exhaust effort stop point (E) in the first cycle and the intake maximum effort point (C) in the second cycle. Based on the calculated scalar value, a value corresponding to a certain range of about 10% to about 30% from the maximum inspiration effort point (C) can be detected as the inspiration effort point (A).

In some cases, the intake effort point detector calculates the slope between the exhaust effort stop point (E) in the first cycle and the intake maximum effort point (C) in the second cycle and determines the intake effort point based on the calculated slope. It can be detected.

Here, the range from about 10% to about 30% may be set differently depending on the patient's condition, the cannula's installation condition, etc.

Then, the effort point and stopping point can be calculated in relation to the equation below.

Effort = Pressure × Volume/time = Pressure × Flow(L/min)

In addition, the exhaust effort point detection unit of the present invention determines, from the patient's breathing pattern information, the exhaust maximum effort point (D) at which the change in the patient's exhaust flow rate is maximum, and the exhaust effort stop point at which breathing stops briefly before inspiration after completion of exhaustion. (E) can be extracted, and the exhaust effort point (B) at which the patient starts the exhaust effort can be detected between them by referring to the extracted maximum exhaust effort point (D) and the exhaust effort stop point (E).

Here, the exhaust effort break point (B) can be extracted from the average value of adding the patient's respiratory flow rate during one cycle and dividing it by the number.

The exhaust effort point detector may extract where the maximum exhaust effort point (D) is located relative to the exhaust effort stop point (E) as the zero point.

In addition, the exhaust effort point detector calculates a scalar value between the exhaust effort stop point (E) in the first cycle and the exhaust maximum effort point (D) in the second cycle with reference to at least two cycles, Based on the calculated scalar value, a value corresponding to a certain range of about 10% to about 30% or less from the maximum exhaust effort point (D) can be detected as the exhaust effort point (B).

In some cases, the slope between the exhaust effort stop point (E) in the first cycle and the exhaust maximum effort point (D) in the second cycle may be calculated, and the exhaust effort point (B) may be detected based on the calculated slope. You can.

In addition, the detected intake effort points (A) and exhaust effort points (B) may temporally correspond to a point before the respective maximum intake effort points (C) and maximum exhaust effort points (D).

Therefore, if the flow rate is controlled and supplied at the intake effort point (A) and the exhaust effort point (B), the patient's intake or exhaust effort can be effectively reduced when the patient is maximally inhaling or exhaling.

Figure 9 is a diagram for explaining the high-flow breathing apparatus of the present invention applied to a patient's breathing apparatus.

As shown in FIG. 9, the high-flow breathing apparatus 500 of the present invention can control the supply flow rate of the patient's breathing apparatus 100.

The patient's breathing apparatus 100 includes a mixed gas generator that generates a mixed gas containing oxygen and air, a flow sensor 110, a blower 120, a pressure sensor 130, a humidifier (HF1), and a supply hose ( 140) may include a nasal cannula (C1).

Here, the flow sensor (FS1) 110 may be installed at the front end of the blower 120 or the rear end of the blower 120 depending on the location and configuration to be sensed.

Additionally, the pressure sensor (P1) 130 at the front end may be placed close to the patient.

In addition, the pressure sensor (P2) 160 at the rear stage has the advantage of being able to measure the flow rate and pressure supplied to the patient close to the actual state, but may be detected when the nasal cannula 140 is removed or when the cannula 140 is installed. Depending on the measurement results, the measurement results may vary significantly.

The high-flow breathing apparatus 500 of the present invention administers a heated, humidified mixed gas with a higher concentration than the oxygen concentration in the atmosphere to the patient. It is involved in the patient's breathing time and changes the flow rate of the mixed gas depending on the time of inspiration and exhaustion. , the flow rate can be adjusted.

Here, the present invention can reduce the patient's inspiratory effort by automatically controlling the flow rate of the mixed gas and the inhaled oxygen concentration based on the target blood oxygen saturation value of the patient when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention, in order to solve the problem that resistance, volume, and respiratory effort are detected differently depending on the size of the patient's nostril, the installation state of the cannula, and the anatomical characteristics of the nasal cavity and upper airway, the pressure and flow rate supplied to the patient Based on this, the inhalation and exhalation points can be detected and synchronized with the patient's breathing cycle.

Therefore, the present invention can precede the breathing synchronization process of monitoring and synchronizing the patient's breathing before treatment.

As such, the present invention can reduce the patient's inspiratory effort by controlling the flow rate of the mixed gas based on the patient's blood oxygen saturation target value when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention can provide convenience to medical staff and improve the accuracy of the patient's diagnosis by automatically controlling the inhaled oxygen concentration based on the target blood oxygen saturation value of the patient when the patient's breathing reaches the inspiratory effort point.

In addition, the present invention reduces dead space clinically by supplying a high flow rate of mixed gas sufficient to ventilate the patient's nasal cavity with fresh air when the patient inhales, and reduces the effort of exhalation breathing when the patient exhales. This may reduce the patient's respiratory effort.

The features, structures, effects, etc. described in the present inventions above are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

In addition, although the above description has been made focusing on the examples, this is only an example and does not limit the present invention, and those skilled in the art will understand the above examples without departing from the essential characteristics of the present embodiment. You will be able to see that various modifications and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

500: High-flow breathing apparatus
510: Breathing pattern monitoring unit
520: detection unit
522: Inspiration effort point detection unit
524: Exhaust effort point detection unit
530: Supply flow control unit
540: Memory unit
550: Respiration synchronization unit

Claims (7)

A breathing pattern monitoring unit that collects information on the patient's breathing pattern;
a detection unit that detects at least one of an inhalation effort point at which the patient tries to start inhalation and an exhalation effort point at which the patient tries to start exhalation from the breathing pattern information of the patient;
It includes a supply flow rate controller that adjusts the flow rate of the mixed gas supplied to the patient based on the intake effort point and the exhaustion effort point,
It further includes a memory unit storing a data table containing fraction of inspired oxygen (FiO ₂ ) values for the patient's blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ),
The detection unit,
Extract the maximum inspiratory effort point where the change in inspiratory flow rate is maximum and the expiratory effort stop point where breathing stops briefly before re-inhaling after exhalation, and refer to the extracted expiratory effort stop point and the maximum inspiratory effort point. The point at which the patient starts inspiratory effort is detected as the inspiratory effort point,
The supply flow control unit,
When the patient's breathing reaches the inspiratory effort point, the upper flow rate of the mixed gas is determined based on the target blood oxygen saturation value of the patient, and the flow rate of the mixed gas is increased and supplied according to the determined upper flow rate, Extracting the patient's inhaled oxygen concentration corresponding to the target blood oxygen saturation value of the patient from the data table stored in the memory unit, increasing the flow rate of the mixed gas to supply the extracted inhaled oxygen concentration,
When the target blood oxygen saturation value of the patient decreases, the upper flow rate limit of the mixed gas is increased to reduce the patient's inspiratory effort,
When increasing the flow rate of the mixed gas, the inhaled oxygen concentration of the mixed gas can be varied according to the target blood oxygen saturation value of the patient,
When changing the inhaled oxygen concentration of the mixed gas, if the target blood oxygen saturation value of the patient varies, the inhaled oxygen concentration value for the varied blood oxygen saturation is extracted from the data table stored in the memory unit and the inhaled oxygen concentration value of the mixed gas is extracted. A high-flow breathing device characterized by variable inhaled oxygen concentration. delete delete delete According to claim 1,
The inhaled oxygen concentration of the mixed gas is,
A high-flow breathing device characterized in that the lower limit is 21% to 96% and the upper limit is 25% to 100%. According to clause 5,
The lower and upper limits of the inspired oxygen concentration are,
A high-flow breathing apparatus, characterized in that it satisfies the relational expression: lower limit of inhaled oxygen concentration ≤ (upper limit of inhaled oxygen concentration - 4). In the control method of a high-flow breathing device including a breathing pattern monitoring unit, a detection unit, a supply flow control unit, and a memory unit,
Collecting, by the breathing pattern monitoring unit, information on the patient's breathing pattern;
detecting, by the detection unit, at least one of an inhalation effort point at which the patient tries to start inhalation and an exhalation effort point at which the patient tries to start exhalation from the breathing pattern information of the patient;
Confirming, by the supply flow rate control unit, whether the patient's breathing reaches the inspiratory effort point;
determining, by the supply flow rate control unit, an upper limit value of the flow rate of the mixed gas supplied to the patient based on the target blood oxygen saturation (Saturation of partial pressure oxygen, SpO ₂ ) of the patient when the inspiration effort point is reached;
When the supply flow control unit reaches the inspiration effort point, the patient's inspired oxygen concentration (Fraction of inspired oxygen, FiO ₂ ) corresponding to the target blood oxygen saturation value of the patient is extracted and determined from the data table stored in the memory unit. step;
The supply flow rate controller increases and supplies the flow rate of the mixed gas according to the determined upper limit of the flow rate of the mixed gas, and increasing the flow rate of the mixed gas to achieve the determined intake oxygen concentration,
The step of detecting the inspiration effort point is,
The detection unit extracts an inspiration maximum effort point where the change in inspiration flow rate is maximum and an exhaust effort stop point where breathing briefly stops before re-inhalation after exhaustion, and the extracted exhaust effort stop point and the inspiration maximum effort point are For reference, the point at which the patient starts inspiratory effort is detected as the inspiratory effort point,
The step of increasing the flow rate of the mixed gas is,
When the blood oxygen saturation target value of the patient decreases, the supply flow rate controller increases the upper flow rate limit of the mixed gas to reduce the patient's inspiratory effort,
When increasing the flow rate of the mixed gas, the inhaled oxygen concentration of the mixed gas can be varied according to the target blood oxygen saturation value of the patient,
When changing the inhaled oxygen concentration of the mixed gas, if the target blood oxygen saturation value of the patient varies, the inhaled oxygen concentration value for the varied blood oxygen saturation is extracted from the data table stored in the memory unit and the inhaled oxygen concentration value of the mixed gas is extracted. A method of controlling a high-flow breathing apparatus, characterized in that the inhaled oxygen concentration is varied.

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