Breathing gas supply device and control method therefor

Abstract

[Problem] In a breath-synchronized breathing gas supply device that supplies breathing gas in accordance with a breathing cycle, a detection error of the start of an inspiration phase caused by the influence of erroneous detection due to the continuous non-detection of inspiration, external disturbance, or the like is reduced. [Solution] The present invention is provided with a pressure sensor and a control unit which determines, as an inspiration detection point, a point at which the value of pressure data calculated on the basis of a signal from the pressure sensor becomes less than an inspiration determination threshold value, and starts the supply of breathing gas. The present invention quickly determines the occurrence of non-detection and erroneous detection of inspiration on the basis of changes in the inspiration detection cycle, and automatically optimizes the determination conditions for inspiration detection corresponding to the current breathing pattern of the user.

Description

Technical Field

[0001] The present invention relates to a respiration-synchronized respiratory gas supply device and a control method thereof. The respiration-synchronized respiratory gas supply device supplies respiratory gases such as concentrated oxygen corresponding to the respiratory cycle of a user. Background Art

[0002] As a treatment method for respiratory diseases such as asthma, emphysema, and chronic bronchitis, oxygen inhalation therapy is performed to supplement insufficient oxygen by having a patient inhale a high-concentration oxygen gas. Home oxygen inhalation therapy means that a patient, i.e., a user, follows a doctor's prescription and operates a respiratory gas supply device such as an oxygen concentrator or an oxygen cylinder to perform oxygen inhalation therapy at home. Recently, a battery-driven portable oxygen concentrator has been developed, and the uses of respiratory gas supply devices are expanding.

[0003] Regarding portable respiratory gas supply devices, in order to achieve miniaturization and weight reduction of the device and long-term operation, many are respiration-synchronized devices having an on-demand adjustment function (Patent Documents 1 and 2). The on-demand adjustment function means that a pressure sensor or the like is used to detect the start of inhalation by a user, and respiratory gases such as oxygen gas are supplied only during the inhalation phase in synchronization with the respiratory cycle, and the supply is stopped during the exhalation phase. Instead of continuously supplying respiratory gases, they are supplied in a pulsed manner corresponding to the user's respiratory cycle, thereby seeking to save respiratory gases and reduce power consumption.

[0004] For the scheme of detecting the start of inhalation using the on-demand adjustment function, a method has been designed in which a pressure sensor is provided in a gas supply path for supplying gas to a cannula to detect a pressure change accompanying the start of inhalation. For example, there is a method of determining the start of inhalation when the pressure value detected by the pressure sensor is lower than a pre-determined pressure value threshold, or when the time change rate (pressure gradient) of the pressure value from the exhalation phase to the inhalation phase side exceeds a pre-determined pressure gradient threshold. Patent Document 3 describes an on-demand adjustment function that detects different respiratory phases depending on activity states such as quiet, labor, and sleep, and supplies inhalation gas in synchronization with each respiratory cycle.

[0005] In addition, a technique for stably detecting inhalation regardless of the respiratory state has been designed. This technique determines the respiratory rate and the like for a period in which the cycle of inhalation detection is not disordered and is substantially constant. When the number of inhalation detections is lower than a certain threshold number, a situation where inhalation is shallow and the start of inhalation is not correctly detected is predicted, so the determination condition for the start of inhalation is relaxed; when the number of inhalation detections exceeds a certain threshold number, a situation where external interference other than respiration is excessively detected is predicted, so the determination condition for the start of inhalation is made stricter (Patent Document 4).

[0006]

Prior Art Documents

Patent Documents

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0007]

Problems to be Solved by the Invention

[0008] The present invention has been completed in view of such a situation, and an object thereof is to provide a breathing gas supply device having a demand - adjustment function, in which the occurrence of non - detection and false detection of inhalation is quickly determined based on changes in the inhalation detection cycle, and the determination conditions for inhalation detection are automatically optimized to correspond to the current breathing pattern of the user.

[0009]

Solutions to the Problems

[0010] (1) The first breathing gas supply device of the present invention is a respiration - synchronous breathing gas supply device that supplies breathing gas corresponding to the breathing cycle of a user, characterized in that the breathing gas supply device includes: a pressure sensor that measures the pressure of a gas supply path; and a control unit that selects one inhalation determination threshold from a plurality of predetermined inhalation determination thresholds, The control unit determines the inhalation detection point as the point at which the value of the pressure data calculated based on the signal of the pressure sensor becomes less than the selected inhalation determination threshold, and supplies the breathing gas for a certain period according to the inhalation detection point. When the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is greater than X%, the control unit switches the inhalation determination threshold to an inhalation determination threshold larger than the selected inhalation determination threshold. When the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is lower than Y%, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

[0011] (2) In the breathing gas supply device according to (1), characterized in that the n1 times is 2 or more times.

[0012] (3) In the breathing gas supply device according to (1), characterized in that the n2 times is 3 or more times.

[0013] (4) In the breathing gas supply device according to any one of (1) to (3), characterized in that the X% is a value greater than 600% and less than 1000%.

[0014] (5) In the breathing gas supply device according to any one of (1) to (4), characterized in that the Y% is a value greater than 10% and less than 17%.

[0015] (6) In the breathing gas supply device according to any one of (1) to (5), characterized in that when the largest inhalation determination threshold among the established multiple inhalation determination thresholds is selected, and when the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is greater than X%, the control unit switches the supply of the breathing gas to continuous supply for a certain period or pulsed supply at a certain cycle.

[0016] (7) The second breathing gas supply device of the present invention is a respiration-synchronized breathing gas supply device that supplies breathing gas corresponding to the user's breathing cycle, characterized in that the breathing gas supply device includes: A pressure sensor for measuring the pressure of the gas supply path; and A control unit that selects one inhalation determination threshold from a plurality of established inhalation determination thresholds, The control unit determines the inhalation detection point as the point at which the value of the pressure data calculated based on the signal of the pressure sensor becomes less than the selected inhalation determination threshold, and supplies the breathing gas for a certain period of time based on the inhalation detection point. When the total value of the time intervals between the inhalation detection points in the most recent n3 times is longer than the first time, the control unit switches the inhalation determination threshold to an inhalation determination threshold larger than the selected inhalation determination threshold. When the total value of the time intervals between the inhalation detection points in the most recent n3 times is shorter than the second time, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

[0017] (8) In the breathing gas supply device according to (7), characterized in that the n3 times is 2 times or more.

[0018] (9) In the breathing gas supply device according to (7) or (8), characterized in that the first time is a time longer than n3×7.5 seconds.

[0019] (10) In the breathing gas supply device according to any one of (7) to (9), characterized in that the second time is a time lower than n3×1.2 seconds.

[0020] (11) In the breathing gas supply device according to any one of (7) to (10), characterized in that when the largest inhalation determination threshold among the predetermined multiple inhalation determination thresholds is selected, and when the total value of the time intervals between the inhalation detection points in the most recent n3 times is longer than the first time, the control unit switches the supply of the breathing gas to continuous supply for a certain period of time or pulsed supply at a certain cycle.

[0021] (12) In the breathing gas supply device according to any one of (1) to (11), characterized in that the value of the pressure data is a pressure value or a pressure gradient value.

[0022] (13) In the breathing gas supply device according to any one of (1) to (12), characterized in that the inhalation determination threshold is a pressure threshold or a pressure gradient threshold.

[0023] (14) In the breathing gas supply device according to any one of (1) to (13), characterized in that as the inhalation determination threshold, it at least includes a first pressure gradient threshold and a second pressure gradient threshold greater than the first pressure gradient threshold. The first pressure gradient threshold is -4.0 Pa / 20 ms or more and -1.0 Pa / 20 ms or less. The second pressure gradient threshold is -0.8 Pa / 20 ms or more and -0.1 Pa / 20 ms or less.

[0024] (15) In the breathing gas supply device according to any one of (1) to (13), it is characterized in that as the inhalation determination threshold, it includes at least a first pressure threshold and a second pressure threshold greater than the first pressure threshold. The first pressure threshold is -10.0 Pa or more and -5.0 Pa or less, and the second pressure threshold is -3.0 Pa or more and -1.0 Pa or less.

[0025] (16) The third breathing gas supply device of the present invention is a respiration-synchronized breathing gas supply device that supplies breathing gas corresponding to the breathing cycle of a user, and is characterized in that the breathing gas supply device includes: a pressure sensor that measures the pressure of the gas supply path; and a control unit that selects one inhalation determination threshold from a plurality of predetermined inhalation determination thresholds. The control unit determines the point at which the value of the pressure data calculated from the signal of the pressure sensor becomes smaller than the selected inhalation determination threshold as the inhalation detection point, and supplies the breathing gas for a certain period of time based on the inhalation detection point, and switches the inhalation determination threshold based on the minimum value of the pressure values during the most recent 7.5 seconds.

[0026] (17) In the breathing gas supply device according to (16), it is characterized in that when the minimum value of the pressure values during the most recent 7.5 seconds is greater than the first pressure determination threshold, the control unit switches the inhalation determination threshold to an inhalation determination threshold greater than the selected inhalation determination threshold. when the minimum value of the pressure values during the most recent 7.5 seconds is less than the second pressure determination threshold, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

[0027] (18) In the breathing gas supply device according to (16) or (17), it is characterized in that the first pressure determination threshold is -10 Pa or more and -5 Pa or less, and the second pressure determination threshold is -100 Pa or more and -50 Pa or less.

[0028] (19) In the breathing gas supply device according to any one of (1) to (18), it is characterized in that the breathing gas is enriched oxygen, and the breathing gas supply device is an oxygen concentrator.

[0029] (20) The control method of the first breathing gas supply device of the present invention is a control method of a respiration-synchronized breathing gas supply device that supplies breathing gas corresponding to the breathing cycle of a user, and is characterized by having: an inhalation determination threshold selection step of selecting one inhalation determination threshold from a plurality of predetermined inhalation determination thresholds; An inspiration detection point detection step of detecting an inspiration detection point at which a value of pressure data calculated from a signal of a pressure sensor that detects the respiratory cycle becomes less than an inspiration determination threshold selected in the inspiration determination threshold selection step; and An inspiration determination threshold switching step of switching the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds based on a time interval between the most recent n1 inspiration detection points, In the inspiration determination threshold switching step, when a value of (average value of time intervals between the most recent n1 inspiration detection points)÷(average value of time intervals between the most recent n2 inspiration detection points) is greater than X%, the inspiration determination threshold is switched to an inspiration determination threshold larger than the selected inspiration determination threshold, and when the value of (average value of time intervals between the most recent n1 inspiration detection points)÷(average value of time intervals between the most recent n2 inspiration detection points) is less than Y%, the inspiration determination threshold is switched to an inspiration determination threshold smaller than the selected inspiration determination threshold.

[0030] (21) A control method for a second respiratory gas supply device of the present invention is a control method for a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to a user's respiratory cycle, and is characterized by having: An inspiration determination threshold selection step of selecting one inspiration determination threshold from a plurality of predetermined inspiration determination thresholds; An inspiration detection point detection step of detecting an inspiration detection point at which a value of pressure data calculated from a signal of a pressure sensor that detects the respiratory cycle becomes less than the inspiration determination threshold selected in the inspiration determination threshold selection step; and An inspiration determination threshold switching step of switching the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds based on a time interval between the most recent n3 inspiration detection points, In the inspiration determination threshold switching step, when a total value of time intervals between the most recent n3 inspiration detection points is longer than a first time, the inspiration determination threshold is switched to an inspiration determination threshold larger than the selected inspiration determination threshold, and when the total value of time intervals between the most recent n3 inspiration detection points is shorter than a second time, the inspiration determination threshold is switched to an inspiration determination threshold smaller than the selected inspiration determination threshold.

[0031] (22) A control method for a third respiratory gas supply device of the present invention is a control method for a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to a user's respiratory cycle, and is characterized by having: an inspiration determination threshold selection step of selecting one inspiration determination threshold from a plurality of predetermined inspiration determination thresholds; Inspiration detection point detection step, detecting an inspiration detection point at which the value of the pressure data calculated based on the signal of the pressure sensor for detecting the respiratory cycle becomes less than the inspiration determination threshold selected in the inspiration determination threshold selection step; and Inspiration determination threshold switching step, switching the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds based on the minimum value of the pressure values during the most recent 7.5 seconds.

[0032] (23) In the control method of the respiratory gas supply device according to (22), characterized in that, in the inspiration determination threshold switching step, when the minimum value of the pressure values during the most recent 7.5 seconds is greater than the first pressure determination threshold, the inspiration determination threshold is switched to an inspiration determination threshold larger than the selected inspiration determination threshold, and when the minimum value of the pressure values during the most recent 7.5 seconds is less than the second pressure threshold, the inspiration determination threshold is switched to an inspiration determination threshold smaller than the selected inspiration determination threshold.

[0033] (24) In the control method of the respiratory gas supply device according to any one of (20) to (23), characterized in that it further has a step of pulse-supplying the respiratory gas for a certain period of time if an inspiration detection point is detected in the inspiration detection point detection step.

[0034]

Effects of the present invention

[0035]

Figure 1

[0036]

Figure 2

[0037]

Figure 3

[0038]

Figure 4

[0039]

【 Figure 5is a flowchart of an inhalation determination threshold switching that includes switching to automatic continuous supply of breathing gas.

[0040]

【 Figure 6 is a flowchart of an inhalation determination threshold switching that includes switching to automatic pulsed supply of breathing gas.

[0041]

【 Figure 7 is a diagram schematically showing a case of determining inhalation using a pressure gradient threshold for waking breathing patterns and sleeping breathing patterns.

[0042]

【 Figure 8 is a diagram schematically showing a case of determining inhalation using a pressure threshold for waking breathing patterns and sleeping breathing patterns. DETAILED DESCRIPTION

[0043] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0044] Figure 7 is a diagram schematically showing a breathing pattern when a person is awake and a breathing pattern when sleeping. Generally, breathing becomes shallower during sleep, so the breathing pattern during sleep ( Figure 7 (b)) has a smaller pressure amplitude and a smaller pressure gradient at 0 Pa from the expiratory phase to the inspiratory phase side compared to the breathing pattern when awake ( Figure 7 (a)). In the present invention, the pressure gradient value is calculated as (current pressure value) - (pressure value 20 ms ago) using the pressure value calculated from the signal of the pressure sensor. In addition, in the present invention, the pressure value calculated from the signal of the pressure sensor and the pressure gradient value are sometimes collectively referred to as pressure data. In addition, as can be understood from Figure 7 and Figure 8 , the pressure gradient value from the expiratory phase to the inspiratory phase side of the breathing pattern and the pressure value in the inspiratory phase are always below zero.

[0045] For example, regarding the Figure 7 breathing pattern, the pressure gradient threshold (hereinafter, sometimes also referred to as "threshold A") is set to -2.0 Pa / 20 ms, and the point at which the pressure gradient value measured by the pressure sensor becomes smaller than the threshold A (the point where the slope becomes larger) is taken as the inhalation detection point G, and this inhalation detection point G is judged as the start of the inspiratory phase. In the breathing pattern when awake, that is, Figure 7 (a), immediately after transitioning from the expiratory phase to the inspiratory phase, the pressure gradient value becomes the maximum gradient of -4.0 Pa / 20 ms and becomes smaller than the threshold A, so the start of the inspiratory phase can be detected as the inhalation detection point G.

[0046] On the other hand, in the breathing pattern during sleep, that is, Figure 7In (b), the breathing is shallow and slow compared to when awake. Therefore, even for a pressure gradient value of -1.0 Pa / 20 ms at the maximum gradient, it is less likely to be less than the threshold A (less likely to have a larger slope). As a result, the inhalation detection point G is not detected, and it is prone to detection errors at the start of the inhalation phase. At this time, for example, if the threshold A is reset to -0.2 Pa / 20 ms, the sensitivity increases, and even when the pressure gradient value at the maximum gradient is -1.0 Pa / 20 ms, the inhalation detection point G can be detected. However, if the threshold A suitable for the sleeping state is set when awake, the sensitivity is too high, and even noise from the pressure sensor caused by vibrations during carrying of the breathing gas supply device or minor body movements is detected as a pressure change caused by breathing, and false detection of the inhalation detection point G often occurs.

[0047] The breathing synchronous breathing gas supply device of the embodiment stores a plurality of inhalation determination thresholds. As the inhalation determination threshold A, in addition to the aforementioned pressure gradient threshold, a pressure threshold can also be used. Regarding the pressure threshold, for example, for Figure 8 a breathing pattern, the pressure threshold (hereinafter, sometimes also referred to as "threshold A") is set to -10 Pa, and the point at which the pressure value measured by the pressure sensor becomes less than the threshold A is used as the inhalation detection point G, and this inhalation detection point G is judged as the start of the inhalation phase. In the breathing pattern when awake, that is, Figure 8 (a), immediately after transitioning from the exhalation phase to the inhalation phase, the pressure value becomes less than the threshold A, so the start of the inhalation phase can be detected as the inhalation detection point G.

[0048] On the other hand, in the breathing pattern during sleep, that is, Figure 8 (b), since the breathing is shallow and slow compared to when awake, if the minimum pressure value is -5.0 Pa, it is less likely to be less than the threshold A. As a result, the inhalation detection point G is not detected, and it is prone to detection errors at the start of the inhalation phase. At this time, for example, if the threshold A is reset to -1.0 Pa, the sensitivity increases, and even when the minimum pressure value is -5.0 Pa, the inhalation detection point G can be detected. However, if the threshold A suitable for the sleeping state is set when awake, the sensitivity is too high, and even noise from the pressure sensor caused by vibrations during carrying of the breathing gas supply device or minor body movements is detected as a pressure change caused by breathing, and false detection of the inhalation detection point G often occurs.

[0049] Figure 1 FIG. is a diagram showing the main structure associated with the on-demand adjustment function of the breathing gas supply device. Figure 1In the figure, the solid line indicates the gas flow path, and the dashed line indicates the path of the electrical signal. The breathing gas supply source 1 is, for example, an oxygen concentrator or an oxygen cylinder, etc., and supplies concentrated oxygen, i.e., inhalation gas, at a predetermined pressure and concentration. The control valve 6 is a solenoid valve or the like, and is opened and closed according to a signal from the control unit 5. The gas supplied from the breathing gas supply source 1 is supplied to the user from the cannula 2 through the opening and closing of the control valve 6 controlled by the control unit 5. A pressure sensor 4 is provided on the gas supply path 3 connecting the control valve 6 and the cannula 2.

[0050] The general situation of the on-demand adjustment function will be described. First, the pressure sensor 4 constantly measures the pressure of the gas supply path 3 that changes due to the user's breathing and sends it to the control unit 5. The control unit 5 detects the inhalation detection point G based on the real-time breathing pattern obtained through the pressure sensor 4, determines the inhalation detection point G as the start of the inhalation phase and opens the control valve 6, and closes the control valve 6 after supplying a certain flow rate of breathing gas to the cannula 2 for a certain period of time. In addition, in order to reliably use almost all of the oxygen supply amount for oxygen exchange in the alveoli, generally, since the oxygen supplied after the first 60% of inhalation stays in the dead space and does not participate in the gas exchange in the alveoli, and the patient's breathing rate is generally about 8 - 48 bpm, it is desired to complete the oxygen supply within about 0.24 - 1.2 seconds from the detection of the inhalation detection point G.

[0051] In addition, in parallel with the control of the control valve 6, the control unit 5 determines whether it is necessary to switch the threshold A used for detecting the inhalation detection point G based on the average value of the time intervals between multiple inhalation detection points G. More specifically, based on the average value of the time intervals between the most recent multiple inhalation detection points G, either the inhalation determination threshold suitable for waking (threshold A1, threshold A2, threshold A3) or the inhalation determination threshold suitable for sleeping (threshold A4) is selected to switch the threshold A.

[0052] The breathing gas supply device according to the embodiment stores multiple inhalation determination thresholds, and Figure 2 shows the process in which the control unit 5 determines whether it is necessary to switch the threshold A and switches the threshold A to threshold A1, threshold A2, threshold A3, or threshold A4.

[0053] When the device starts up and the on-demand adjustment function is operating, the control unit 5 sets the threshold A to the lowest sensitivity among the thresholds suitable for waking, i.e., the inspiration determination threshold (threshold A1) (step S1). When using the pressure gradient threshold as the inspiration determination threshold, as a result of measuring and studying the breathing patterns of multiple HOT patients during waking, it is known that as the first pressure gradient threshold, it is preferably set in the range of 4.0 Pa / 20 ms to -1.0 Pa / 20 ms, more preferably the threshold A1 is in the range of -4.0 ± 1.0 Pa / 20 ms, the threshold A2 is in the range of -2.0 ± 1.0 Pa / 20 ms, and the threshold A3 is in the range of -1.0 ± 0.5 Pa / 20 ms. In addition, when using the pressure threshold as the inspiration determination threshold, as a result of measuring and studying the breathing patterns of multiple HOT patients during waking, it is known that as the first pressure threshold, it is preferably set in the range of -10.0 Pa to -5.0 Pa, more preferably the threshold A1 is in the range of -10.0 ± 2.0 Pa, the threshold A2 is in the range of -5.0 ± 2.0 Pa, and the threshold A3 is in the range of -3.0 ± 1.0 Pa. As a result of measuring and studying the breathing patterns of multiple HOT patients during sleep for the threshold A4, it is known that in order to keep the ratio (detection rate) of the number of inspiration detection points G to the actual number of breaths at 75% or more, when using the pressure gradient threshold as the inspiration determination threshold, as the second pressure gradient threshold, the threshold A4 is preferably -0.8 Pa / 20 ms to -0.1 Pa / 20 ms, more preferably in the range of -0.2 ± 0.05 Pa / 20 ms. In addition, when using the pressure threshold as the inspiration determination threshold, it is known that as the second pressure threshold, the threshold A4 is preferably -3.0 Pa to -1.0 Pa, more preferably in the range of -1.0 ± 0.5 Pa.

[0054] When the first pressure gradient threshold (threshold A1, threshold A2, threshold A3) is less than -4.0 Pa / 20 ms, the first pressure threshold (threshold A1, threshold A2, threshold A3) is less than -10.0 Pa, the second pressure gradient threshold (threshold A4) is less than -0.8 Pa / 20 ms, or the second pressure threshold (threshold A4) is less than -3.0 Pa, respectively, due to insufficient sensitivity for the breathing patterns of patients during waking and sleeping, the detection rate of the inspiration detection point G relative to the actual number of breaths becomes less than 75%, and sufficient breathing gas cannot be supplied to keep the user's blood oxygen saturation (SpO2) above 90%, which is a general appropriate value.

[0055] In addition, when the first pressure gradient thresholds (threshold A1, threshold A2, threshold A3) are greater than -1.0 Pa / 20 ms, the first pressure thresholds (threshold A1, threshold A2, threshold A3) are greater than -5.0 Pa, the second pressure gradient threshold (threshold A4) is greater than -0.1 Pa / 20 ms, or the second pressure threshold (threshold A4) is greater than -1.0 Pa, the detection rate of the inhalation detection point G with respect to the actual breathing frequency becomes 130% or more. The proportion of misdetecting the noise of the pressure sensor 4 as the inhalation detection point G increases. Since the breathing gas is not supplied in synchronization with the start of inhalation, the user feels discomfort, and the consumption of the breathing gas also increases.

[0056] The control unit 5 detects the inhalation detection point G based on the threshold A1 set in step S1 and the pressure gradient value or pressure value calculated from the signal of the pressure sensor 4, and starts the pulsed supply of the breathing gas in synchronization with the start of inhalation.

[0057] Next, the control unit 5 determines whether it is necessary to switch from threshold A1 to threshold A2, from threshold A2 to threshold A3, or from threshold A3 to threshold A4 (steps S2, S5, and S8) using the latest value data of the time intervals between the most recent inhalation detection points G and the average value data of the time intervals between the most recent multiple inhalation detection points G. More specifically, when (the average value of the time intervals between the most recent n1 inhalation detection points G since the measurement start) ÷ (the average value of the time intervals between the most recent n2 inhalation detection points G) is greater than X%, it is determined that the breathing is not correctly detected, and the inhalation determination threshold is switched to a threshold with higher sensitivity. At this time, n1 can be set to the detection times of the inhalation detection points G that can be any value of 2 or more including the most recently detected inhalation detection point G. For example, in the case of "the time interval between the most recent 2 inhalation detection points G", it means the time interval between the most recent two inhalation detection points G. n2 can be set to the detection times of the inhalation detection points G that can be any value of 3 or more including the most recently detected inhalation detection point G, and n1 < n2 is set. In addition, in order to optimize the sensitivity earlier, it is desirable that n1 is set to 2 times, and n2 is set to a value of 5 or more and 10 or less.

[0058] Regarding the determination of whether to switch the inhalation determination threshold, since it is known that the breathing rate of a person is generally around 8 to 48 bpm, and the breathing cycle of a person changes up to about 600% at most as the state changes from a laborious state (maximum 48 bpm) to a quiet state (minimum 8 bpm), in order to avoid unnecessary switching to a threshold with higher sensitivity despite being able to correctly detect breathing, it is desirable that X% be set to a value greater than 600%. In addition, in order to optimize the sensitivity earlier, it is desirable that X% be less than 1000%. When (the average value of the time intervals between the inhalation detection points G in the most recent n1 times) ÷ (the average value of the time intervals between the inhalation detection points G in the most recent n2 times) is greater than X%, there is a high possibility that the inhalation detection point G cannot be correctly detected at the current threshold A (threshold A1, threshold A2, or threshold A3). Therefore, when (the average value of the time intervals between the inhalation detection points G in the most recent n1 times) ÷ (the average value of the time intervals between the inhalation detection points G in the most recent n2 times) becomes greater than X%, the control unit 5 switches the threshold A to an inhalation determination threshold with a higher level of sensitivity (steps S3, S6, S9).

[0059] When the inhalation determination threshold A is switched to an inhalation determination threshold with higher sensitivity, the control unit 5 detects the point at which the pressure gradient value or the pressure value measured by the pressure sensor 4 becomes less than the switched inhalation determination threshold with higher sensitivity as the inhalation detection point G, and supplies breathing gas in pulses. For example, by switching the inhalation determination threshold A to an inhalation determination threshold A4 with higher sensitivity, it is possible to also detect the start point of the inhalation phase during sleep that was likely to be undetected at the thresholds A1 to A3 as the inhalation detection point G.

[0060] When selecting the threshold A2, threshold A3, or threshold A4, the latest value data of the time intervals between the nearest inspiration detection points G and the average value data of the time intervals between the nearest multiple inspiration detection points G are used to determine whether to switch from threshold A4 to threshold A3, or from threshold A3 to threshold A2, or from threshold A2 to threshold A1 (steps S4, S7, and S10). More specifically, when (the average value of the time intervals between the inspiration detection points G in the most recent n1 times since the measurement start) ÷ (the average value of the time intervals between the inspiration detection points G in the most recent n2 times) is less than Y%, it is determined that an external disturbance such as body movement has been erroneously detected, and the inspiration determination threshold is switched to a threshold with lower sensitivity. At this time, as described above, n1 can be set to the detection count of the inspiration detection points G which can be any value of 2 or more including the most recently detected inspiration detection point G, and n2 can be set to the detection count of the inspiration detection points G which can be any value of 3 or more including the most recently detected inspiration detection point G, with n1 < n2. In addition, in order to optimize the sensitivity earlier, it is desirable that n1 is set to 2 times, and n2 is set to a value of 5 or more and 10 or less. As described above, the human breathing rate is about 8 - 48 bpm, so it can be known that as the transition from the quiet state (minimum 8 bpm) to the working state (maximum 48 bpm) progresses, the human breathing cycle changes by up to about 17%. Therefore, in order to avoid unnecessary switching to a threshold A with lower sensitivity although breathing can be correctly detected, it is desirable that Y% is set to a value less than 17%. In addition, in order to optimize the sensitivity earlier, it is desirable that Y% is set to a value greater than 10%. When (the average value of the time intervals between the inspiration detection points G in the most recent n1 times) ÷ (the average value of the time intervals between the inspiration detection points G in the most recent n2 times) becomes lower than Y%, under the condition that the inspiration detection point G is detected using the current threshold A (threshold A2, threshold A3, or A4), the sensitivity is too high and the possibility of erroneously detecting noise as the inspiration detection point G is relatively high. Therefore, when (the average value of the time intervals between the inspiration detection points G in the most recent n1 times) ÷ (the average value of the time intervals between the inspiration detection points G in the most recent n2 times) becomes lower than Y%, the control unit 5 switches the threshold A to an inspiration determination threshold with one lower level of sensitivity (steps S1, S3, and S6).

[0061] In this way, the control unit 5 switches the inspiration determination threshold based on the latest value data of the time intervals between the nearest inspiration detection points G and the average value data of the time intervals between the nearest multiple inspiration detection points G, and controls the on-demand adjustment function corresponding to the user's state. Therefore, it is possible to correctly detect the start of the inspiration phase and supply breathing gas synchronized with the respiratory cycle.

[0062] In addition, the inspiration determination threshold can also be switched using the total value data of the time intervals between the most recent multiple inspiration detection points G. More specifically, when the total value of the time intervals between the most recent n3 inspiration detection points G is longer than the first time (tsumup), it is determined that respiration has not been correctly detected, and the inspiration determination threshold is switched to a higher-sensitivity threshold. Conversely, when the total value of the time intervals between the most recent n3 inspiration detection points G is shorter than the second time (tsumdown), it is determined that an external disturbance such as body movement has been erroneously detected, and the inspiration determination threshold is switched to a lower-sensitivity threshold. At this time, n3 can be set to the number of detections of the inspiration detection point G, which can be any value of 2 or more including the most recently detected inspiration detection point G. In addition, in order to optimize the sensitivity earlier, it is desirable that n3 be set to a value of 5 or more and 10 or less. Further, considering that the normal breathing rate of a person is about 8 to 48 bpm, in order to avoid unnecessary switching of the inspiration determination threshold despite being able to correctly detect respiration, it is desirable that tsumup be set to a time longer than n3 × 7.5 seconds, and tsumdown be set to a time shorter than n3 × 1.2 seconds. In addition, 7.5 seconds corresponds to the breathing interval at 8 bpm, and 1.2 seconds corresponds to the breathing interval at 48 bpm.

[0063] In addition, the inspiration determination threshold can also be switched based on the minimum value of the pressure values during the most recent 7.5 seconds ( Figure 3 ; steps S12, S15, and S18). More specifically, when the minimum value of the pressure values during the most recent 7.5 seconds is greater than the first pressure determination threshold P1, it is determined that the respiratory pressure is extremely weak and it is difficult to perform correct inspiration detection, and the inspiration determination threshold is switched to a higher-sensitivity threshold (steps S13, S16, and S19). Conversely, when the minimum value of the pressure values during the most recent 7.5 seconds is less than the second pressure determination threshold P2, it is determined that due to excessive respiratory pressure, a situation is likely to occur where an erroneous detection is caused by body movement such as a working state, and the inspiration determination threshold is switched to a lower-sensitivity threshold (steps S11, S13, and S16). At this time, as a result of measuring and studying the breathing patterns of multiple HOT patients during waking and sleeping, it is desirable that the first pressure determination threshold P1 be -10 Pa or more and -5 Pa or less, and the second pressure determination threshold P2 be -100 Pa or more and -50 Pa or less.

[0064] In the respiratory gas supply device according to the embodiment, the user can also send a sensitivity switching signal from the user interface 7 to the control unit 5 to manually switch the threshold. Figure 4 is an example of a process that can switch the sensitivity by manual operation of the user.

[0065] When the device starts and the on-demand adjustment function is working, the control unit 5 sets the threshold A to the threshold A1 (step S21). When the user presses the sensitivity increase button of the user interface 7 (step S22), it enters step S24, and the threshold A1 is switched to the threshold A2. Similarly, when the threshold A is set to A2 or A3 (steps S24 and S29), when the sensitivity increase button is pressed (steps S25 and S30), it enters steps S29 and S34, and the threshold A is switched to A3 and A4 respectively. In addition, when controlling the respiratory gas supply device with the threshold A2, when the user presses the sensitivity decrease button (step S26), it enters step S21 and switches to the threshold A1. Similarly, when the threshold A is set to A3 or A4 (steps S29 and S34), when the sensitivity decrease button is pressed (steps S31 and S35), it enters steps S24 and S29, and the threshold A is switched to A2 and A3 respectively. In Figure 4 In the example of, the operation of the sensitivity switching button performed by the user takes precedence over the judgment made by the control unit 5 based on whether (the average value of the time intervals between the last n1 inspiratory detection points G) ÷ (the average value of the time intervals between the last n2 inspiratory detection points G) becomes greater than X%, and the pressure gradient threshold is switched.

[0066] Figure 5 is an example that has a safety function of continuously supplying respiratory gas for about 90 seconds regardless of the respiratory phase in addition to performing pulsed supply of respiratory gas synchronized with the respiratory phase. The process until step S50 is the same as that of Figure 2 steps S1 to 10. In step S50, when (the average value of the time intervals between the last n1 inspiratory detection points G) ÷ (the average value of the time intervals between the last n2 inspiratory detection points G) is greater than Y%, in step S51, it is checked whether (the average value of the time intervals between the last n1 inspiratory detection points G) ÷ (the average value of the time intervals between the last n2 inspiratory detection points G) becomes greater than X%, and it is confirmed whether the minimum number of breaths can be detected.

[0067] As described above, since the normal respiratory rate of a person is about 8 to 48 bpm, for example, when (the average value of the time intervals between the last n1 inspiratory detection points G) ÷ (the average value of the time intervals between the last n2 inspiratory detection points G) becomes greater than 600% (equivalent to 8 bpm), although it is controlled with the high-sensitivity threshold A4, the interval between the inspiratory detection points G is long and there is a high possibility that the respiratory gas is not supplied sufficiently. Therefore, the control unit 5 switches the supply method of the respiratory gas to continuous supply (automatic continuous flow) (step S52). According to Figure 1, during the continuous supply of breathing gas, the control valve 6 is in a continuously open state, and the pressure sensor 4 outputs the pressure of the breathing gas as the detected pressure. Therefore, during this period, it is impossible to detect the pressure changes accompanying breathing. Therefore, it is necessary to periodically stop the continuous supply of breathing gas to confirm whether the user's breathing has returned to an intensity that can be sufficiently detected. Therefore, when a certain period of time has elapsed since the start of the automatic continuous flow supply, the control unit 5 returns the threshold A to A4 and starts detecting the inhalation detection point G again (step S55). According to the inventor's research, as a result of measuring and studying the breathing patterns of multiple HOT patients during sleep, setting the supply time of the automatic continuous flow to 10 seconds to 120 seconds makes it highly likely to inhale breathing gas for more than 75% of the total breathing time, and about 90 seconds is more preferable.

[0068] Figure 6 is an example of a safety function that, in addition to performing pulsed supply of breathing gas synchronized with the breathing phase, also supplies breathing gas in pulses at a certain period regardless of the breathing phase. The process up to steps S61 to S71 is the same as Figure 5 steps S41 to S51 of

[0069] The control unit 5 replaces the supply of the automatic continuous flow ( Figure 5 step S52), and switches the supply method of the breathing gas to pulsed supply (automatic pulse) at a certain period (for example, 50 bpm) (step S72). During the period of this automatic pulse operation, the detection of the inhalation detection point G using the threshold A4 is also continuously performed. If the inhalation detection point G is detected again, the control unit 5 cancels the automatic pulse supply (step S75).

[0070] In addition, in step S51 or step S71, if ((average value of time intervals between the most recent n1 inhalation detection points G) ÷ (average value of time intervals between the most recent n2 inhalation detection points G)) is set to 1000% or more, it is almost impossible to detect the inhalation detection point G, and the supply of the automatic continuous flow or automatic pulse is delayed, and sufficient breathing gas cannot be supplied to the user during sleep, resulting in a reduction in the therapeutic effect brought by the breathing gas supply device. Therefore, it is desirable that X% be set to a value greater than 600% and less than 1000%. Moreover, when the switching condition to the automatic continuous flow or automatic pulse is satisfied 5 times during a 30-minute period (step S51 or step S71) (step S53 or step S73), it is determined that there is a high possibility of some abnormality in the user or the breathing gas supply device, and an alarm is sounded (step S54 or step S74).

[0071] In Figure 5 , Figure 6In the process, even when it becomes a state where it is almost impossible to detect the inspiration detection point G and the breathing gas cannot be sufficiently supplied by the on-demand adjustment function, since the breathing gas is automatically supplied by the supply of automatic continuous flow or automatic pulse, the risk that the user feels dyspnea is reduced.

[0072] In addition, in the above content as an example of the embodiment, the number of levels of the inspiration determination threshold that can be switched is set to 4 levels, but the inspiration determination threshold can also be set to an arbitrary number of levels within the scope of the above switching method.

[0073] As described above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited to the above embodiments, and various deformations and changes can be made within the scope of the gist of the present invention described in the claims.

[0074]

Industrial Applicability

[0075]

Reference Signs Explanation

Claims

1. A respiratory gas supply device is a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to the user's breathing cycle, characterized in that the respiratory gas supply device includes: a pressure sensor that measures the pressure of the gas supply path; and a control unit that selects one inhalation determination threshold from a plurality of predetermined inhalation determination thresholds, the control unit determines the point at which the value of the pressure data calculated based on the signal of the pressure sensor becomes less than the selected inhalation determination threshold as the inhalation detection point, and supplies the respiratory gas for a certain period of time based on the inhalation detection point, when the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is greater than X%, the control unit switches the inhalation determination threshold to an inhalation determination threshold larger than the selected inhalation determination threshold, when the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is less than Y%, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

2. The breathing gas supply device according to claim 1, wherein, The n1 times is 2 or more times.

3. The breathing gas supply device according to claim 1 or 2, characterized in that, The n2 times is 3 or more times.

4. The respiratory gas supply device according to any one of claims 1 to 3, characterized in that, The X% is a value greater than 600% and less than 1000%.

5. The respiratory gas supply device according to any one of claims 1 to 4, characterized in that The Y% is a value greater than 10% and less than 17%.

6. The respiratory gas supply device according to any one of claims 1 to 5, characterized in that When the largest inhalation determination threshold among the predetermined plurality of inhalation determination thresholds is selected, and when the value of (average value of time intervals between the most recent n1 inhalation detection points) ÷ (average value of time intervals between the most recent n2 inhalation detection points) is greater than X%, the control unit switches the supply of the respiratory gas to continuous supply for a certain period of time or pulsed supply at a certain cycle.

7. A respiratory gas supply device is a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to the user's breathing cycle, characterized in that the respiratory gas supply device includes: a pressure sensor that measures the pressure of the gas supply path; and a control unit that selects one inhalation determination threshold from a plurality of predetermined inhalation determination thresholds, the control unit determines the point at which the value of the pressure data calculated based on the signal of the pressure sensor becomes less than the selected inhalation determination threshold as the inhalation detection point, and supplies the respiratory gas for a certain period of time based on the inhalation detection point, when the total value of the time intervals between the most recent n3 inhalation detection points is longer than a first time, the control unit switches the inhalation determination threshold to an inhalation determination threshold larger than the selected inhalation determination threshold, when the total value of the time intervals between the most recent n3 inhalation detection points is shorter than a second time, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

8. The respiratory gas supply device according to claim 7, wherein, The n3 times is 2 or more times.

9. The breathing gas supply device according to claim 7 or 8, characterized in that, The first time is a time longer than n3 × 7.5 seconds.

10. The respiratory gas supply device according to any one of claims 7 to 9, characterized in that The second time is a time less than n3 × 1.2 seconds.

11. The breathing gas supply device according to any one of claims 7 to 10, characterized in that, When the maximum inhalation determination threshold among the predetermined multiple inhalation determination thresholds is selected and the total value of the time intervals between the inhalation detection points in the most recent n3 times is longer than the first time, the control unit switches the supply of the breathing gas to continuous supply for a certain period of time or pulsed supply at a certain cycle.

12. The respiratory gas supply device according to any one of claims 1 to 11, characterized in that, The value of the pressure data is a pressure value or a pressure gradient value.

13. The breathing gas supply device according to any one of claims 1 to 12, characterized in that, The inhalation determination threshold is a pressure threshold or a pressure gradient threshold.

14. The breathing gas supply device according to any one of claims 1 to 13, characterized in that As the inhalation determination threshold, it includes at least a first pressure gradient threshold and a second pressure gradient threshold greater than the first pressure gradient threshold. The first pressure gradient threshold is not less than -4.0 Pa / 20 ms and not more than -1.0 Pa / 20 ms. The second pressure gradient threshold is not less than -0.8 Pa / 20 ms and not more than -0.1 Pa / 20 ms.

15. The breathing gas supply device according to any one of claims 1 to 13, characterized in that As the inhalation determination threshold, it includes at least a first pressure threshold and a second pressure threshold greater than the first pressure threshold. The first pressure threshold is not less than -10.0 Pa and not more than -5.0 Pa. The second pressure threshold is not less than -3.0 Pa and not more than -1.0 Pa.

16. A breathing gas supply device, which is a respiration-synchronized breathing gas supply device that supplies breathing gas corresponding to the user's breathing cycle, characterized in that The breathing gas supply device includes: A pressure sensor for measuring the pressure of the gas supply path; and A control unit that selects one inhalation determination threshold from a predetermined multiple inhalation determination thresholds. The control unit determines the point at which the value of the pressure data calculated from the signal of the pressure sensor becomes smaller than the selected inhalation determination threshold as an inhalation detection point, and supplies the breathing gas for a certain period of time based on the inhalation detection point. Based on the minimum value of the pressure value during the most recent 7.5 seconds, the inhalation determination threshold is switched.

17. The breathing gas supply device according to claim 16, characterized in that When the minimum value of the pressure value during the most recent 7.5 seconds is greater than the first pressure determination threshold, the control unit switches the inhalation determination threshold to an inhalation determination threshold larger than the selected inhalation determination threshold. When the minimum value of the pressure value during the most recent 7.5 seconds is less than the second pressure determination threshold, the control unit switches the inhalation determination threshold to an inhalation determination threshold smaller than the selected inhalation determination threshold.

18. The respiratory gas supply device according to claim 16 or 17, characterized in that, The first pressure determination threshold is not less than -10 Pa and not more than -5 Pa, and the second pressure determination threshold is not less than -100 Pa and not more than -50 Pa.

19. The breathing gas supply device according to any one of claims 1 to 18, characterized in that, The breathing gas is enriched oxygen, and the breathing gas supply device is an oxygen concentrator.

20. A control method for a breathing gas supply device, which is a control method performed by the control unit of a respiration-synchronized breathing gas supply device that supplies breathing gas corresponding to the user's breathing cycle, characterized in that The control unit controls the following steps: Inspiration determination threshold selection step of selecting one inspiration determination threshold from a plurality of predetermined inspiration determination thresholds; Inspiration detection point detection step of detecting an inspiration detection point at which the value of the pressure data calculated based on the signal of the pressure sensor that detects the respiratory cycle becomes less than the inspiration determination threshold selected in the inspiration determination threshold selection step; and Inspiration determination threshold switching step of switching the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds based on the time intervals between the most recent n1 inspiration detection points, In the inspiration determination threshold switching step, when the value of (average value of the time intervals between the most recent n1 inspiration detection points) ÷ (average value of the time intervals between the most recent n2 inspiration detection points) is greater than X%, the inspiration determination threshold is switched to an inspiration determination threshold larger than the selected inspiration determination threshold, and when the value of (average value of the time intervals between the most recent n1 inspiration detection points) ÷ (average value of the time intervals between the most recent n2 inspiration detection points) is less than Y%, the inspiration determination threshold is switched to an inspiration determination threshold smaller than the selected inspiration determination threshold.

21. A control method for a respiratory gas supply device, which is a control method performed by a control unit of a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to a user's respiratory cycle, characterized in that the control unit controls the following steps: Inspiration determination threshold selection step of selecting one inspiration determination threshold from a plurality of predetermined inspiration determination thresholds; Inspiration detection point detection step of detecting an inspiration detection point at which the value of the pressure data calculated based on the signal of the pressure sensor that detects the respiratory cycle becomes less than the inspiration determination threshold selected in the inspiration determination threshold selection step; and Inspiration determination threshold switching step of switching the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds based on the time intervals between the most recent n3 inspiration detection points, In the inspiration determination threshold switching step, when the total value of the time intervals between the most recent n3 inspiration detection points is longer than a first time, the inspiration determination threshold is switched to an inspiration determination threshold larger than the selected inspiration determination threshold, and when the total value of the time intervals between the most recent n3 inspiration detection points is shorter than a second time, the inspiration determination threshold is switched to an inspiration determination threshold smaller than the selected inspiration determination threshold.

22. A control method for a respiratory gas supply device, which is a control method performed by a control unit of a respiration-synchronized respiratory gas supply device that supplies respiratory gas corresponding to a user's respiratory cycle, characterized in that the control unit controls the following steps: Inspiration determination threshold selection step of selecting one inspiration determination threshold from a plurality of predetermined inspiration determination thresholds; Inspiration detection point detection step of detecting an inspiration detection point at which the value of the pressure data calculated based on the signal of the pressure sensor that detects the respiratory cycle becomes less than the inspiration determination threshold selected in the inspiration determination threshold selection step; and Inspiration determination threshold switching step, based on the minimum value of the pressure values during the most recent 7.5 seconds, switch the one inspiration determination threshold to any one of the plurality of inspiration determination thresholds.

23. The control method of the breathing gas supply device according to claim 22, characterized in that, In the inspiration determination threshold switching step, when the minimum value of the pressure values during the most recent 7.5 seconds is greater than the first pressure determination threshold, switch the inspiration determination threshold to an inspiration determination threshold larger than the selected inspiration determination threshold; when the minimum value of the pressure values during the most recent 7.5 seconds is less than the second pressure threshold, switch the inspiration determination threshold to an inspiration determination threshold smaller than the selected inspiration determination threshold.

24. The control method of a breathing gas supply device according to any one of claims 20 to 23, characterized in that, It further has a step of supplying the respiratory gas in pulses for a certain period of time if an inspiration detection point is detected in the inspiration detection point detection step.

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