JP7343762B2 - Breathing detection device and oxygen concentrator - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a respiration sensing device and an oxygen concentrator.

Patent Document 1 below describes a generation section that generates oxygen-enriched gas with increased oxygen concentration, a discharge section that discharges the oxygen-enriched gas generated in the generation section, and a supply of oxygen-enriched gas that connects the generation section and the discharge section. An oxygen concentrator is disclosed that includes a pressure sensor connected to a flow path, a cannula connected to a discharge section, and a control section that controls a generation section and the like. A pressure sensor detects respiration of a cannulated patient by measuring pressure changes in the supply channel. The control unit detects the patient's state, such as a resting state or an exertion state, based on the detected respiratory waveform, and adjusts the supply flow rate of the oxygen-enriched gas.

Japanese Patent Application Publication No. 2018-114194

In conventional oxygen concentrators, turbulence occurs in the flow of oxygen-enriched gas in the generation section or in the supply flow path from the generation section to the discharge section, which adds vibration to the pressure of the oxygen-enriched gas. Vibration may become noise and be detected by the pressure sensor. Such noise causes a decrease in accuracy when detecting a patient's condition from a respiratory waveform, for example.

An object of the present disclosure is to provide a respiration detection device and an oxygen concentrator that can reduce pressure noise in a supply flow path from an oxygen-concentrated gas generator to a discharge port of a cannula.

(1) The respiration detection device of the present disclosure includes a pressure sensor for detecting pressure changes in oxygen-enriched gas in a supply flow path connecting an oxygen-enriched gas generation part in an oxygen concentrator and an oxygen-enriched gas discharge port in a cannula. a connecting pipe that connects the supply flow path and the pressure sensor and allows oxygen-enriched gas to flow from the supply flow path to the pressure sensor; and a noise provided in the connection pipe that reduces noise added to the pressure of the oxygen-enriched gas. It is equipped with a filter.

According to the above configuration, by reducing the noise added to the pressure of the oxygen-enriched gas in the supply flow path using the noise filter, changes in the pressure of the oxygen-enriched gas can be accurately measured by the pressure sensor, and the patient's breathing can be accurately detected. be able to. Therefore, for example, the patient's condition can be accurately determined using the respiratory waveform.

(2) Preferably, the noise filter has a hole formed therein that has an inner diameter smaller than the inner diameter of the connecting pipe and allows oxygen-enriched gas to pass therethrough.
According to the above configuration, noise can be reduced by allowing the oxygen-enriched gas to pass through the hole having an inner diameter smaller than the inner diameter of the connecting pipe.

(3) Preferably, the inner diameter of the hole is 0.025 times or more and 0.25 times or less than the inner diameter of the connecting pipe.
With this configuration, pressure changes can be measured by the pressure sensor while reducing noise.

(4) Preferably, the distance between the pressure sensor and the noise filter is four times or more the inner diameter of the connecting pipe.
With this configuration, it is possible to suppress disturbances in the flow of oxygen-enriched gas that has passed through the holes of the noise filter from affecting the measured value of the pressure sensor.

(5) Preferably, the noise filter has an expansion chamber that has an inner diameter larger than the inner diameter of the connecting pipe and allows oxygen-enriched gas to pass therethrough.
According to this configuration, pressure noise can be reduced by causing oxygen-enriched gas to flow into the expansion chamber of the noise filter.

(6) Preferably, the oxygen concentrator includes a discharge section for discharging oxygen-concentrated gas to the outside of the oxygen concentrator, and a supply flow path between the generation section and the discharge section for discharging oxygen-concentrated gas. It has a flow rate adjustment section that adjusts the flow rate.
If the oxygen concentrator is equipped with a flow rate adjustment section, the flow path is narrowed or widened to adjust the flow rate of oxygen-enriched gas, which tends to cause disturbances in the flow of oxygen-enriched gas and cause pressure noise. It becomes easier. Therefore, it is more effective to provide a noise filter as described above.

(7) Preferably, the oxygen concentrator has a discharge part for discharging oxygen to the outside of the oxygen concentrator, and the connecting pipe is connected between the discharge part and the discharge port of the cannula. It is connected to an oxygen-enriched gas supply flow path between the two.
With the above configuration, the respiration detection device can be attached to the outside of the oxygen concentrator. Therefore, a breath detection function can be added to an oxygen concentrator that does not have a breath detection function.

(8) The oxygen concentrator of the present disclosure includes:
a generating section that generates oxygen-enriched gas;
a discharge section that discharges the oxygen-enriched gas generated in the generation section;
The respiration detection device according to any one of (1) to (6) above,
A connecting pipe of the respiration detection device is connected to an oxygen-enriched gas supply flow path connecting the generation section and the discharge section.

With the above configuration, the breathing detection device is built into the oxygen concentrator, and the patient's breathing state detected using the pressure sensor and the operating status of the oxygen concentrator can be managed in association with each other.

FIG. 1 is a schematic diagram showing an oxygen concentrator having a respiration detection device according to a first embodiment. 1 is a schematic cross-sectional view of a respiration sensing device; FIG. FIG. 7 is a schematic cross-sectional view showing a modification of the respiration detection device. FIG. 2 is a schematic diagram showing a respiration detection device and an oxygen concentrator according to a second embodiment. FIG. 2 is an explanatory diagram showing a piping connection portion of the respiration detection device.

Hereinafter, a respiration detection device and an oxygen concentrator according to embodiments will be described with reference to the drawings.
[First embodiment]
FIG. 1 is a schematic diagram showing an oxygen concentrator having a respiration detection device according to a first embodiment.
As shown in FIG. 1, the oxygen concentrator 11 supplies oxygen-enriched gas to a patient undergoing oxygen inhalation therapy. A cannula 21 used for inhaling oxygen-enriched gas through the nose is connected to the oxygen concentrator 11, and the oxygen-enriched gas is supplied to a patient wearing the cannula 21.

The cannula 21 is formed into a tubular shape from a synthetic resin such as vinyl chloride resin, and includes a supply channel 21b through which oxygen-enriched gas flows. An inlet 21c through which the oxygen-enriched gas flows is formed at one end of the supply channel 21b, and a pair of discharge ports 21a through which the oxygen-enriched gas is discharged is formed at the other end. The inlet 21c is connected to the oxygen concentrator 11, and the pair of outlet ports 21a are inserted into the patient's nose. Note that a device for discharging oxygen-enriched gas other than the cannula 21 may be connected to the oxygen concentrator 11.

The oxygen concentrator 11 includes a generation section 12 , a flow rate adjustment section 13 , a discharge section 14 , a respiration detection section (respiration detection device) 31 , and a control section 16 . The generation section 12 , the flow rate adjustment section 13 , and the discharge section 14 are connected by a supply channel 15 . The generation section 12 , the flow rate adjustment section 13 , the discharge section 14 , the respiration detection section 31 , the control section 16 , and the supply channel 15 are provided in one casing 17 .

The generator 12 generates oxygen-enriched gas. The generator 12 compresses air taken into the oxygen concentrator 11 from the outside using a known pressure swing adsorption method, and adsorbs nitrogen in the compressed air with an adsorbent such as zeolite, thereby reducing the oxygen concentration. Generates oxygen enriched gas around 90%. The oxygen-enriched gas generated in the generation section 12 is sent to the discharge section 14 via the flow rate adjustment section 13.

The discharge section 14 discharges the oxygen-enriched gas generated by the generation section 12 to the outside of the oxygen concentrator 11 . The discharge part 14 protrudes from the casing 17 to the outside so that the inlet 21c of the cannula 21 can be connected thereto. The discharge part 14 is configured by a joint pipe or the like for connecting the cannula 21.

The flow rate adjustment unit 13 adjusts the flow rate of oxygen-enriched gas supplied to the patient. For example, the flow rate adjustment unit 13 adjusts the flow rate of oxygen-enriched gas to be supplied to the patient according to the state of respiration detected by the respiration detection unit 31. The flow rate adjustment section 13 is composed of a valve or the like whose opening degree can be adjusted.

The control unit 16 is constituted by a microcomputer including a calculation unit such as a CPU, and memory such as a RAM and a ROM. The control unit 16 controls the operation of the generation unit 12, the flow rate adjustment unit 13, the respiration detection unit 31, etc. by having the CPU execute a control operation program stored in the memory. The control unit 16 also has a function of outputting various information stored in the memory.

FIG. 2 is a schematic cross-sectional view of the breath detection section.
The breathing detection section 31 includes a connecting pipe 32, a pressure sensor 33, and a noise filter 34. One end of the connecting pipe 32 is connected to the middle of the supply channel 15 . A pressure sensor 33 is provided at the other end of the connecting pipe 32. A noise filter 34 is provided inside the connecting pipe 32 between the supply channel 15 and the pressure sensor 33.

The connecting pipe 32 is a pipe made of synthetic resin such as polyurethane. The inner diameter d1 of the connecting tube 32 is, for example, 4 mm. However, the inner diameter d1 of the connecting pipe 32 can be changed as appropriate.

The pressure sensor 33 is a condenser microphone using an electret element that is semi-permanently charged. A condenser microphone can measure dynamic pressure changes at low frequencies, such as 0.5 Hz, and is suitable for measuring sound pressures of 1 Pa or less.

The pressure sensor 33 is inserted inside the other end of the connecting tube 32 . The pressure sensor 33 can measure the pressure of the oxygen-enriched gas flowing from the supply channel 15 to the connecting pipe 32. The pressure within the supply channel 15 changes depending on the patient's breathing. Specifically, as the patient inhales oxygen-enriched gas through cannula 21, the pressure within supply channel 15 decreases. When the patient exhales, the pressure of the patient's exhaled breath acts into the cannula 21 from the discharge port 21a, so that the pressure within the supply channel 15 increases. The pressure sensor 33 measures pressure changes within the supply channel as the patient breathes. Since the patient's breathing alternately and periodically repeats exhalation and inhalation, the measured value of the pressure sensor 33 indicates a periodically changing respiration waveform.

The control unit 16 acquires the pressure change (respiration waveform) measured by the pressure sensor 33 and stores it in the memory.
The memory of the control unit 16 stores the supply flow rate of oxygen-enriched gas according to the patient's condition. The patient's state includes, for example, a resting state, an exertion state, and a sleeping state. The supply flow rate of oxygen-enriched gas depending on the patient's condition is, for example, 2 L in a resting state, 2.5 L in an exertion state, and 1.5 L in a sleeping state. The supply flow rates of these oxygen-enriched gases are prescribed in advance by a doctor, input into the control unit 16, and stored.

The control unit 16 determines the respiratory rate from the patient's respiratory waveform measured by the pressure sensor 33, and determines the patient's state (resting state, exertion state, sleep state) based on the magnitude of the fluctuation range. When the control unit 16 determines the patient's condition, it determines the flow rate of the oxygen-enriched gas accordingly. The control unit 16 controls the flow rate adjustment unit 13 based on the determined flow rate of oxygen-enriched gas. Thereby, oxygen can be supplied to the patient at an appropriate flow rate based on the patient's respiratory waveform.

The memory of the control unit 16 also stores operational information such as the operating status of the oxygen concentrator 11. This driving information and the patient's respiratory waveform information are associated with each other. For example, information about the date and time when the oxygen concentrator 11 was activated and information about the respiratory waveform at that time are stored in the memory of the control unit 16 in a correlated manner. This information can be used by a doctor to understand the usage status of the oxygen concentrator 11 by the patient, such as whether the patient is using the oxygen concentrator 11 as prescribed. For example, if the respiratory waveform is not properly acquired even though the oxygen concentrator 11 is in operation, the patient may be using the oxygen concentrator 11 without properly wearing the cannula 21. You can guess. Furthermore, by measuring the breathing rate and breathing interval obtained from the patient's breathing information over a long period of time and examining the progress, it is possible to understand whether the patient's condition is worsening or improving. Therefore, the doctor can reflect the information stored in the memory in the treatment and examination of the patient.

When the oxygen-concentrated gas is discharged from the generation section 12 or when the flow rate is adjusted by the flow rate adjustment section 13, vibrations are added to the pressure in the process of reaching the discharge section 14, and the vibrations are generated as noise and are detected by the pressure sensor. 33 may be detected. The respiration detection unit 31 of this embodiment includes a noise filter 34 to suppress detection of noise by the pressure sensor 33.

The noise filter 34 of the breathing detection section 31 is formed in a cylindrical shape. The noise filter 34 is attached to the connecting tube 32 with its outer peripheral surface in close contact with the inner peripheral surface of the connecting tube 32. A hole 34a having an inner diameter d2 smaller than the inner diameter d1 of the connecting pipe 32 is formed in the noise filter 34. The oxygen-enriched gas flowing through the connecting pipe 32 from the supply channel 15 passes through the hole 34a and reaches the pressure sensor 33.

The inner diameter d2 of the hole 34a of the noise filter 34 has a relationship with the inner diameter d1 of the connecting pipe 32 as expressed by the following equation (1).
0.025d1≦d2≦0.25d1 (1)

Preferably, the inner diameter d2 of the hole 34a of the noise filter 34 has a relationship with the inner diameter d1 of the connecting pipe 32 as expressed by the following equation (2).
0.1d1≦d2≦0.15d1 (2)

More preferably, the inner diameter d2 of the hole 34a of the noise filter 34 has a relationship with the inner diameter d1 of the connecting pipe 32 as expressed by the following equation (1).
d2=0.125d1...(3)

The distance L between the noise filter 34 and the pressure sensor 33 has the relationship expressed by the following equation (4).
L≧4d1...(4)

[Operations and effects of this embodiment]
(1) The respiration detection unit (respiration detection device) 31 of the first embodiment described above is configured to provide a supply flow connecting the oxygen-enriched gas generation unit 12 in the oxygen concentrator 11 and the oxygen-enriched gas discharge port 21a in the cannula 21. a pressure sensor 33 for detecting pressure changes in the oxygen-enriched gas in the passage 15; a connecting pipe 32 that connects the supply passage 15 and the pressure sensor 33 and allows the oxygen-enriched gas to flow from the supply passage 15 to the pressure sensor 33; A noise filter 34 is provided on the connecting pipe 32 and reduces noise added to the pressure of the oxygen-enriched gas.

According to the respiration detection unit 31 having such a configuration, the noise added to the pressure of the oxygen-enriched gas in the supply channel 15 can be reduced by the noise filter 34, and the pressure change of the oxygen-enriched gas can be accurately detected by the pressure sensor 33. It is possible to accurately detect the patient's respiratory waveform. Therefore, it is possible to accurately determine the patient's condition, understand changes in the patient's condition, understand the usage status of the oxygen concentrator 11, etc. using this respiratory waveform.

(2) In the first embodiment described above, the noise filter 34 is formed with a hole 34a that has an inner diameter d2 smaller than the inner diameter d1 of the connecting pipe 32 and allows oxygen-enriched gas to pass therethrough. Therefore, noise can be reduced by passing the oxygen-enriched gas through the holes 34a of the noise filter 34.

(3) In the first embodiment described above, as shown in the above equation (1), the inner diameter d2 of the hole 34a of the noise filter 34 is 0.025 times or more and 0.25 times the inner diameter d1 of the connecting pipe 32. It is as follows. If the inner diameter d2 of the hole 34a is less than 0.025 times the inner diameter d1 of the connecting pipe 32, it becomes difficult for oxygen-enriched gas to pass through the hole 34a, making it difficult to measure pressure changes with the pressure sensor 33. . If the inner diameter d2 of the hole 34a exceeds 0.25 times the inner diameter d1 of the connecting pipe 32, the noise reduction effect will be reduced. Therefore, by setting the inner diameter d2 of the hole 34a of the noise filter 34 to 0.025 times or more and 0.25 times or less the inner diameter d1 of the connecting pipe 32, the pressure sensor 33 can detect pressure changes while reducing noise. can be measured.

(4) In the first embodiment described above, the distance L between the pressure sensor 33 and the noise filter 34 is set to be at least four times the inner diameter d1 of the connecting pipe 32, as shown in equation (4) above. . This is due to the following reason. When the oxygen-enriched gas passes through the holes 34a of the noise filter 34, the flow may be slightly disturbed. If the distance between the pressure sensor 33 and the noise filter 34 is less than four times the inner diameter d1 of the connecting pipe 32, the disturbance in the flow of oxygen-enriched gas caused by passing through the hole 34a will affect the measured value of the pressure sensor 33. more likely to give. As described above, by setting the distance L between the pressure sensor 33 and the noise filter 34 to be at least four times the inner diameter d1 of the connecting pipe 32, disturbances in the flow of the oxygen-enriched gas passing through the hole 34a of the noise filter 34 can be prevented. , can be suppressed from influencing the measured value of the pressure sensor 33.

(5) In the first embodiment described above, the oxygen concentrator 11 has a discharge section 14 for discharging oxygen-enriched gas to the outside of the oxygen concentrator 11, and a connection between the generation section 12 and the discharge section 14. The supply flow path 15 includes a flow rate adjustment section 13 that adjusts the flow rate of oxygen-enriched gas. When the oxygen concentrator 11 is equipped with the flow rate adjustment unit 13 in this way, the flow path is narrowed or expanded to adjust the flow rate of the oxygen-enriched gas, which tends to cause disturbances in the flow of the oxygen-enriched gas. Pressure noise is also more likely to occur. Therefore, it is more effective to include the noise filter 34 as described above.

(6) The oxygen concentrator 11 of the first embodiment described above includes a generation section 12 that generates oxygen-enriched gas, a discharge section 14 that discharges the oxygen-enriched gas generated in the generation section 12, and a respiration detection section 31. , and a connecting pipe 32 of the respiration detection section 31 is connected to an oxygen-enriched gas supply channel 15 that connects the generation section 12 and the discharge section 14. Therefore, the breathing detection unit 31 is built into the oxygen concentrator 11, and the patient's breathing state detected using the pressure sensor 33 and the operating state of the oxygen concentrator 11 can be managed in association with each other.

[Modified example of breath detection device]
FIG. 3 is a schematic cross-sectional view showing a modification of the respiration detection device.
The noise filter 34 of this breathing detection device 31 is different from that shown in FIG. 2 and has an expansion chamber 34b having an inner diameter d3 larger than the inner diameter d1 of the connecting pipe 32.
In the case of this noise filter 34, the oxygen-enriched gas that has flowed into the connecting pipe 32 from the supply channel 15 enters the expansion chamber 34b, thereby reducing pressure vibrations and suppressing noise detection by the pressure sensor 33.

[Second embodiment]
FIG. 4 is a schematic diagram showing a respiration detection device and an oxygen concentrator according to a second embodiment.
The respiration detection device 31 of this embodiment is configured separately from the oxygen concentrator 11 and is externally attached to the oxygen concentrator 11 .

The breathing detection device 31 includes a noise filter 34, a pressure sensor 33, a connecting pipe 32, and a control section 35. These are provided within the casing 36. One end of the connecting tube 32 is connected to the discharge section 14 of the oxygen concentrator 11 and the cannula 21 by a coupling member 37.

The configurations of the noise filter 34, pressure sensor 33, and connecting pipe 32 are the same as in the first embodiment. The control unit 35 is constituted by a microcomputer including a calculation unit such as a CPU, and memory such as a RAM and a ROM. The control unit 35 controls the operation of the pressure sensor 33 and the like by the CPU executing a control operation program stored in the memory. Among the functions of the control unit 16 of the first embodiment, the control unit 35 has a function of acquiring the measured value of the pressure sensor 33 and storing it in a memory as respiratory waveform information. Furthermore, the control unit 35 has a function of outputting information stored in the memory.

FIG. 5 is an explanatory diagram showing the piping connection portion of the respiration detection device.
The joint member 37 has one end connected to the discharge part 14 of the oxygen concentrator 11, as illustrated in FIG. 5, for example. The other end of the coupling member 37 is connected to the end of the connecting tube 32 and the inlet 21c of the cannula 21. A branch flow path that branches from the discharge portion 14 to the connecting tube 32 and the cannula 21 is formed inside the joint member 37 . Therefore, the connecting pipe 32 is connected to the oxygen-concentrated gas supply flow path between the discharge part 14 of the oxygen concentrator 11 and the discharge port 21a of the cannula 21 (see FIG. 4).

In the respiration detection device 31 of the second embodiment, the connection tube 32 is connected to the oxygen-enriched gas supply channel between the discharge part 14 and the discharge port 21a of the cannula 21. It can be attached to the outside of the oxygen concentrator 11. Therefore, a breath detection function can be added to the oxygen concentrator 11 that does not have a breath detection function.

The present disclosure is not limited to the description of the embodiments described above, but is indicated by the claims, and further includes all changes within the meaning and range equivalent to the claims.
For example, in the embodiment described above, a condenser microphone is used as the pressure sensor 33, but other pressure sensors such as a diaphragm type can be used as long as they can detect the patient's respiratory waveform. However, since a diaphragm pressure sensor requires stabilization of the reference pressure and is large in size, it is more preferable to use a condenser microphone as in the above embodiment.

11: Oxygen concentrator 12: Generating section 13: Flow rate adjustment section 14: Discharge section 15: Supply channel 21: Cannula 21a: Discharge port 21b: Supply channel 31: Breathing detection device (breath detection section)
32 : Connection pipe 33 : Pressure sensor 34 : Noise filter 34a : Hole 34b : Expansion chamber L : Distance d1 : Inner diameter d2 : Inner diameter

Claims (6)

Changes in the pressure of the oxygen-enriched gas in the supply channel (15, 21b) connecting the oxygen-enriched gas generator (12) in the oxygen concentrator (11) and the oxygen-enriched gas discharge port (21a) in the cannula (21) A pressure sensor (33) for detection is connected to the supply flow path (15, 21b) and the pressure sensor (33), and oxygen concentration is transferred from the supply flow path (15, 21b) to the pressure sensor (33). A connecting pipe (32) through which gas flows, and a noise filter (34) provided in the connecting pipe (32) to reduce noise added to the pressure of the oxygen-enriched gas ,
The noise filter (34) is provided with a hole (34a) that has an inner diameter (d2) smaller than the inner diameter (d1) of the connecting pipe (32) and allows oxygen-enriched gas to pass therethrough. The respiratory detection device according to claim 1 , wherein the inner diameter (d2) of the hole (34a) is 0.025 times or more and 0.25 times or less the inner diameter (d1) of the connecting pipe (32). The respiratory detection device according to claim 1 or 2 , wherein a distance (L) between the pressure sensor (33) and the noise filter (34) is four times or more the inner diameter (d1) of the connecting pipe (32). . The oxygen concentrator (11) has a discharge part (14) for discharging oxygen-enriched gas to the outside of the oxygen concentrator (11), and a space between the generation part (12) and the discharge part (14). The respiration detection device according to any one of claims 1 to 3 , further comprising a flow rate adjustment section (13) that adjusts the flow rate of the oxygen-enriched gas in the supply flow path (15). The oxygen concentrator (11) has a discharge part (14) for discharging oxygen to the outside of the oxygen concentrator (11), and the connecting pipe (32) is connected to the discharge part (14). The respiratory detection device according to any one of claims 1 to 4 , connected to a supply flow path for oxygen-enriched gas between the discharge port (21a) of the cannula (21) and the discharge port (21a) of the cannula (21). a generator (12) that generates oxygen-enriched gas;
a discharge section (14) for discharging the oxygen-enriched gas generated in the generation section (12);
A respiration detection device (31) according to any one of claims 1 to 4 ,
An oxygen concentrator, wherein a connecting pipe (32) of the respiration detection device (31) is connected to an oxygen-concentrated gas supply channel (15) connecting the generation section (12) and the discharge section (14). .

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