Respiration assisting device

Abstract

To provide a respiration assisting device that can accurately capture the respiration waveform of a patient, and that enables appropriate control of blower operation in accordance with the respiration flow of the patient.SOLUTION: A respiration assisting device of the present disclosure includes: a body housing 100A forming an air flow path 132; a blower 131 which is provided in the flow path 132 and generates an air flow; and a differential pressure sensor 164 for measuring a flow rate of the air flow flowing in the flow path 132. The flow path 132 includes: a guide path 132a for guiding the air from an air inlet 113; and a blower installation chamber 132b formed such that a flow path cross-section area increases from a downstream end of the guide path 132a. The differential pressure sensor 164 includes: a first measurement port 164a installed in the guide path 132a; and a second measurement port 164b installed in the blower installation chamber 132b. The flow rate of the air flow is measured on the basis of the pressure difference between the two points of a position of the first measurement port 164a and a position of the second measurement port 164b.SELECTED DRAWING: Figure 6A

Description

[Technical Field]

[0001] The present disclosure relates to respiratory assistance devices. [Background technology]

[0002] Respiratory support devices that supply airflow to a patient's airway, such as a CPAP (Continuous Positive Airway Pressure) device, have been known. CPAP devices are used in CPAP therapy (also known as sleep apnea treatment devices). CPAP therapy is a treatment method for preventing apnea in patients with symptoms of obstructive sleep apnea by continuously supplying air to the patient's airway to open it.

[0003] This type of respiratory assistance device generally has a blower that generates an airflow and a built-in board for controlling the blower within the main body housing, and is configured so that the airflow can be adjusted by the blower to a flow rate appropriate for widening the patient's airway. Some respiratory assistance devices of this type have also been developed that include a humidifier to adjust the temperature and humidity of the airflow supplied to the patient (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-071739 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of respiratory assistance device, a flow sensor is conventionally provided in the air flow path within the housing of the device body to measure the patient's respiratory flow and control the operation (i.e., rotation speed) of the blower based on the measured respiratory flow. The flow sensor is generally a differential pressure sensor, and the air flow rate is measured based on the pressure difference between two points in the flow path.

[0006] Respiratory flow refers to the airflow generated by a patient's breathing (the same applies hereinafter). The magnitude of the airflow flow of the respiratory flow is observed as a respiratory waveform. It is known that a respiratory waveform generally contains not only low-frequency components associated with normal respiratory movements but also high-frequency components of about 10 to 100 Hz caused by snoring.

[0007] The respiratory assistance devices according to the prior art have room for improvement in terms of the accuracy of measuring the patient's respiratory waveform, which means that the prior art respiratory assistance devices may not be able to properly control the operation (i.e., rotation speed) of the blower in accordance with the patient's breathing.

[0008] Therefore, an object of the present invention is to provide a respiratory assistance device that can more accurately capture the respiratory flow of a patient. [Means for solving the problem]

[0009] The main invention that solves the above-mentioned problems is: a main body housing having an air intake port and an air exhaust port, the main body housing forming an air flow path from the air intake port to the air exhaust port; a blower disposed in the flow path for generating a flow of air for delivery to the patient's airway; a differential pressure sensor disposed to detect the state of the air flow and measuring a differential pressure between a first measurement port and a second measurement port disposed in the flow path; Equipped with the flow path includes a guide path that guides the air from the intake port to the position of the blower, and a blower installation chamber that is formed so that the flow path cross-sectional area expands from the downstream end of the guide path, the first measurement port of the differential pressure sensor is disposed within the guideway; The second measurement port of the differential pressure sensor is disposed in the blower installation chamber. It is a respiratory support device. [Effects of the Invention]

[0010] The respiratory assistance device according to the present invention makes it possible to more accurately grasp the respiratory flow of a patient. [Brief explanation of the drawings]

[0011] [Figure 1] Diagram showing a patient wearing a CPAP device [Figure 2A] 1 is a perspective view of a CPAP device according to an embodiment of the present invention, seen from diagonally above; [Figure 2B] 1 is a perspective view of a CPAP device according to an embodiment of the present invention, seen from diagonally above; [Figure 3] 1 is an exploded perspective view of a CPAP device according to an embodiment of the present invention; [Figure 4] Schematic diagram showing air flow paths [Figure 5] FIG. 1 is a block diagram showing the configuration of a CPAP device according to an embodiment of the present invention. [Figure 6A] FIG. 1 is a diagram showing the configuration of a flow path in a CPAP device according to an embodiment of the present invention and the arrangement of a differential pressure sensor. [Figure 6B] FIG. 1 is a diagram showing the configuration of a flow path in a CPAP device according to an embodiment of the present invention and the arrangement of a differential pressure sensor. [Figure 7A] FIG. 1 is a diagram showing the configuration of the flow path and the arrangement of the differential pressure sensor in a CPAP device according to a comparative example. [Figure 7B] FIG. 1 is a diagram showing the configuration of the flow path and the arrangement of the differential pressure sensor in a CPAP device according to a comparative example. [Figure 8] FIG. 1 is a diagram illustrating a mechanism for detecting high-frequency components of changes in air flow rate using a differential pressure sensor according to an embodiment of the present invention. [Figure 9] FIG. 1 is a diagram illustrating a flow rate measurement method according to the prior art; [Figure 10]FIG. 1 is a diagram illustrating problems with flow rate measurement according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functions are designated by the same reference numerals, and redundant description will be omitted.

[0013] In the following, a CPAP device (hereinafter referred to as "CPAP device 100") will be described as a suitable application example of the respiratory assistance device according to the present invention. However, the respiratory assistance device according to the present invention can also be applied to an ASV device (Adaptive Servo Ventilation) or an NHF device (Nasal High Flow) in addition to the CPAP device.

[0014] <1> Configuration of CPAP device 100 according to the embodiment Fig. 1 is a diagram showing a state in which a CPAP device 100 is attached to a patient 1. As shown in Fig. 1, the CPAP device 100 has a mask 10 and a tube 20, and the device main body of the CPAP device 100 is connected via the tube 20 to the mask 10 worn on the face of the patient 1 suffering from sleep apnea syndrome, and sends a positive airflow to the upper airway of the patient 1 to expand the upper airway.

[0015] 2A and 2B are perspective views of the CPAP device 100 viewed from diagonally above. Here, the +Z direction in Fig. 2A and 2B indicates the upward direction of the CPAP device 100, and the -Z direction indicates the downward direction of the CPAP device 100. Furthermore, the +Y direction indicates the forward direction of the CPAP device 100, and the -Y direction indicates the backward direction of the CPAP device 100. Furthermore, the +X direction indicates the leftward direction of the CPAP device 100, and the -X direction indicates the rightward direction of the CPAP device 100.

[0016] As can be seen from Figure 2A, a tube connector 112 to which a tube 20 (see Figure 1) is connected protrudes from the front side of the storage case 110 of the CPAP device 100. An operation panel 111 is provided on the top of the storage case 110. The operation panel 111 is provided with an operation input unit 111a including operation buttons and the like, and a display unit 111b.

[0017] 2B, the rear side of the storage case 110 is provided with an air intake 113 and a power connector 114. AC power is input to the power connector 114 via a power cable. In addition, a water tank 151 is removably attached to the right side of the storage case 110.

[0018] FIG. 3 is an exploded perspective view of the CPAP device 100. As shown in FIG.

[0019] The CPAP device 100 includes a housing case 110, a circuit board 120, a flow path case 130, and a base unit 150.

[0020] In the CPAP device 100 according to this embodiment, the accommodating case 110, the flow path case 130, and the base part 150 constitute the main body housing of the CPAP device 100 (hereinafter also referred to as "main body housing 100A").

[0021] The accommodating case 110 has a rectangular cylindrical shape, and is coupled to the base 150 from above to accommodate the circuit board 120, the flow path case 130, etc. An operation panel 111 is provided on the top of the accommodating case 110.

[0022] As described above, the storage case 110 has the tube connector 112, the air intake 113, and the power connector 114. The tube connector 112 constitutes an air exhaust port of the main body housing 100A.

[0023] The circuit board 120 is provided with a microcomputer, a memory, various driver circuits, and the like.

[0024] Flow path case 130 is configured by fitting together lower case 130a and upper case 130b. A blower 131 is disposed inside flow path case 130. A flow path 132 (described later with reference to FIG. 6) through which air drawn in from air intake port 113 passes is formed inside flow path case 130, and blower 131 is disposed in flow path 132. Note that blower 131 imparts energy to the air drawn in from air intake port 113 and flowing through flow path 132, thereby increasing the pressure and speed of the air, and sends it out to a humidifier side configured by water tank 151 or the like.

[0025] A removable water tank 151 is disposed on the base 150. An air inlet 152a and an air outlet 152b are formed in a lid 152 of the water tank 151. The air inlet 152a communicates with the flow path 132 in the flow path case 130. The air outlet 152b communicates with the tube connector 112.

[0026] As a result, as can be seen from the schematic diagram of Figure 4, the air flow (arrow in Figure 4) generated by blower 131 passes through flow path 132 of flow path case 130, enters water tank 151 through air inlet 152a, is discharged from water tank 151 through air outlet 152b, and is supplied to patient 1 via tube connector 112.

[0027] A heater 153 is provided on the underside of the water tub 151. The water in the water tub 151 is heated by the heater 153, and as a result, the inside of the water tub 151 is kept in a highly humid state. Therefore, the airflow supplied to the patient is humidified in the water tub 151. This prevents the airflow from drying out the airway of the patient 1. That is, in the CPAP device 100 according to this embodiment, the water tub 151, the lid 152, and the heater 153 form a humidifier that humidifies the airflow supplied to the patient 1 (hereinafter also referred to as "humidifier 150A") (see FIG. 5).

[0028] In addition, an AC / DC converter 154 is provided on the base 150. The AC / DC converter 154 receives external AC power from a power cord (not shown) connected to the power connector 114 (FIG. 2B), converts it into DC power, and supplies the converted DC power to the circuit board 120 and the like.

[0029] The multiple circuit components that make up the AC / DC converter 154 are covered below and on both the left and right sides by a sheet metal member 155 that has a U-shaped cross section taken along the XZ plane. The sheet metal member 155 extends in the Y direction. A fan 156 for cooling the AC / DC converter 154 is provided on one end of the sheet metal member 155. The fan 156 is provided in a position facing the AC / DC converter 154.

[0030] As a result, AC / DC converter 154 is efficiently cooled by the wind from fan 156. In addition, electromagnetic noise generated from AC / DC converter 154 is shielded by sheet metal member 155, thereby reducing the impact of electromagnetic noise on other circuit boards, etc.

[0031] Thus, in the CPAP device 100 of this embodiment, air inhaled from the intake port 113 passes through the flow path 132 in the flow path case 130, the blower 131, and the humidifier 150A, and is supplied to the patient 1 via the tube connector 112.

[0032] FIG. 5 is a block diagram illustrating the configuration of the CPAP device 100. As shown in FIG.

[0033] In addition to the blower 131, the flow path 132 of the CPAP device 100 is provided with a filter 161, a temperature and humidity sensor 162, a differential pressure sensor 164, and a pressure sensor 165. Also, a temperature sensor 166 is attached to the heater 153 that heats the water tank 151.

[0034] The circuit board 120 is provided with a control unit 122, a heating control unit 123, a respiratory waveform analysis unit 124, and a communication unit 125. In other words, the circuit board 120 is mounted with circuit components for realizing the functions of the control unit 122, the heating control unit 123, the respiratory waveform analysis unit 124, and the communication unit 125.

[0035] The control unit 122, heating control unit 123, and respiratory waveform analysis unit 124 are configured, for example, by a microcomputer including a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU reads a program corresponding to the processing content from the ROM, loads it into the RAM, and works with the loaded program to realize the functions of the control unit 122, heating control unit 123, and respiratory waveform analysis unit 124. All or part of the control unit 122, heating control unit 123, and respiratory waveform analysis unit 124 may be formed by hardwired circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0036] When blower 131 operates, external air enters flow path 132 via intake port 113 and filter 161. Then, the temperature and humidity of the air in flow path 132 are measured by temperature and humidity sensor 162, and the measured temperature and humidity are sent to control unit 122 and heating control unit 123. Furthermore, heating control unit 123 receives as input a heating set value and a humidification set value (e.g., a target temperature and a target humidity) from operation input unit 111a, as well as temperature information of heater 153 from temperature sensor 166.

[0037] The heating control unit 123 controls the heater 153 based on information on the temperature and humidity measured by the temperature and humidity sensor 162, heating and humidification setting values ​​set by the user from the operation input unit 111a, and temperature information on the heater 153 from the temperature sensor 166. The heating control unit 123 controls the heater 153, for example, so that the temperature and humidity of the airflow supplied to the patient 1 approach the heating and humidification setting values.

[0038] Furthermore, temperature information from a temperature sensor 168 provided in the tube 20 is input to the heating control unit 123. The heating control unit 123 controls a heater 169 provided in the tube 20 based on this temperature information, thereby suppressing condensation inside the tube 20.

[0039] Differential pressure sensor 164 is disposed as a flow sensor that measures the flow rate of the airflow flowing through flow path 132. Differential pressure sensor 164 measures the pressure difference of the airflow between two points, first measurement port 164a and second measurement port 164b (described below with reference to FIGS. 6A and 6B), and sends the measurement result to respiratory waveform analyzer 124. Note that differential pressure sensor 164 may be a differential pressure sensor that performs differential pressure measurement using the thermal flow measurement principle, a differential pressure sensor that performs differential pressure measurement using a pressure-sensitive element, or a differential pressure sensor that performs differential pressure measurement in some other way.

[0040] The differential pressure sensor 164 is disposed at an appropriate position upstream of the blower 131. This is because air turbulence occurs if the sensor is positioned too close to the blower 131 or too far from the blower 131 near the intake port 113 (details will be described later with reference to FIGS. 6A and 6B). Furthermore, downstream of the blower 131, the air flow is pressurized by the blower 131, and the differential pressure cannot be measured accurately by the differential pressure sensor 164, so the differential pressure sensor 164 is disposed upstream of the blower 131.

[0041] The respiratory waveform analysis unit 124 detects the state of airflow based on the measurement data of the differential pressure sensor 164. Here, "detecting the state of airflow" means detecting the airflow rate and airflow vibration. That is, since the airflow vibration is superimposed on the flow rate waveform, the respiratory waveform analysis unit 124 can also detect density changes caused by snoring components (high-frequency components) of breathing (described later with reference to FIG. 8).

[0042] Specifically, the respiratory waveform analysis unit 124 first obtains airflow rate information from the differential pressure obtained as measurement data from the differential pressure sensor 164 using a control map or the like. Then, the respiratory waveform analysis unit 124 detects the respiratory flow (i.e., respiratory waveform) of the patient 1 based on the temporal change in the airflow rate. Then, the respiratory waveform analysis unit 124 performs, for example, frequency analysis (e.g., FFT analysis) on the detected respiratory flow (respiratory waveform) and sends the analysis results (e.g., signal strength for each frequency) to the control unit 122 as respiratory information. Furthermore, the respiratory waveform analysis unit 124 sends the respiratory information to the communication unit 125, for example.

[0043] Furthermore, the respiratory waveform analysis unit 124 may, for example, capture low-frequency components (normal respiratory movement components) and high-frequency components (snoring components) by frequency analysis of the respiratory waveform, and control the rotation of the blower 131 based on the waveform changes for each frequency component.

[0044] Information about the pressure inside the flow path 132 measured by the pressure sensor 165 is sent to the control unit 122. In addition, the control unit 122 receives pressure setting information (for example, target pressure) from the operation input unit 111a.

[0045] The control unit 122 controls the flow rate of the air flow supplied to the patient 1 by controlling the rotation of the blower 131 based on the pressure information measured by the pressure sensor 165, the respiratory information from the respiratory waveform analysis unit 124, and the pressure setting information from the operation input unit 111a set by the user.

[0046] For example, when a high-frequency component with high intensity (i.e., snoring) is detected, the control unit 122 determines that there is airway resistance (i.e., the airway is narrowed and close to being blocked), and increases the pressure to widen the airway (i.e., increases the rotation speed of the blower 131).Furthermore, when a change in low-frequency flow rate due to respiratory movement becomes small, the control unit 122 determines that there is apnea or hypopnea, and increases the pressure to widen the airway (i.e., increases the rotation speed of the blower 131).

[0047] Furthermore, the control unit 122 identifies the operating temperature of the blower 131 based on, for example, information about the temperature measured by the temperature and humidity sensor 162, and if the operating temperature exceeds a threshold temperature, limits or stops the operation of the humidifier 150A to prevent deterioration of the blower 131. The threshold temperature is set to, for example, 50 degrees Celsius.

[0048] The communication unit 125 communicates with the external system 200. For example, respiratory information obtained by the respiratory waveform analysis unit 124 is transmitted to the external system 200 via the communication unit 125. This allows a medical professional located away from the CPAP device 100 to know the respiratory condition of the patient 1, for example, to know that the patient 1 is experiencing apnea.

[0049] <2> Arrangement of differential pressure sensor 164 Next, the configuration of the flow path 132 and the arrangement of the differential pressure sensor 164 within the main body housing 100A according to this embodiment will be described in detail.

[0050] First, the problems with the CPAP device according to the prior art will be described.

[0051] Fig. 9 is a diagram illustrating a flow rate measurement method according to the prior art, and Fig. 10 is a diagram illustrating a problem with the flow rate measurement method according to the prior art.

[0052] Conventionally, flow rate measurements using differential pressure sensors involve placing the two measurement ports of the differential pressure sensor in a flow path, placing a resistor with multiple walls between the two measurement ports, attenuating the gas flow (i.e., generating pressure loss) through frictional resistance on the side walls, and determining the flow rate from the differential pressure before and after the attenuation.

[0053] However, as a result of intensive research by the inventors of the present application, it has been found that conventional methods using such resistors are unable to accurately detect signals of high-frequency components of respiratory flow (for example, high-frequency components of approximately 10 to 100 Hz caused by snoring).

[0054] It is generally known that gas properties cause density changes to occur as the flow velocity increases. In other words, the above phenomenon is thought to occur because changes in airflow (meaning changes in airflow over time) are manifested as changes in flow rate for low-frequency components, but as density changes for high-frequency components.

[0055] In other words, the resistors used in the conventional technology can attenuate changes in airflow velocity (i.e., changes in airflow volume) through frictional resistance, but are thought to allow changes in airflow density to pass through (see Figure 10). Therefore, the conventional technology that uses resistors to measure the airflow volume cannot adequately obtain the differential pressure of the airflow caused by high-frequency components of the respiratory flow between the two measurement ports of the differential pressure sensor. As a result, the conventional technology cannot adequately detect signals with high-frequency components of around 10 to 100 Hz caused by snoring, etc.

[0056] This means that conventional respiratory support devices may not be able to adequately grasp respiratory disorders such as snoring or airway resistance, and therefore may not be able to properly control the operation of the blower (i.e., rotation speed) in accordance with the patient's breathing.

[0057] In the CPAP device 100 according to this embodiment, the differential pressure sensor 164 is arranged in a manner that takes such problems into consideration.

[0058] 6A and 6B are diagrams showing the arrangement of the differential pressure sensor 164 in the CPAP device 100 according to this embodiment. Fig. 6A shows a plan view of the flow path 132 formed in the flow path case 130. Fig. 6B also shows the positions of the first and second measurement ports 164a, 164b of the differential pressure sensor 164 in the flow path 132.

[0059] FIG. 8 is a diagram showing a schematic diagram of a mechanism for detecting high frequency components of changes in air flow rate by the differential pressure sensor 164 according to this embodiment.

[0060] The flow path 132 includes a guide path 132a that guides the air introduced into the intake port 113, and a blower installation chamber 132b that is formed so as to be connected to the downstream end of the guide path 132a.

[0061] The guide path 132a has at least one bent portion 132aa-132ad to guide the air so that it makes a long detour inside the main body housing 100A from the intake port 113 to the position of the blower 131 (i.e., the blower installation chamber 132b). The guide path 132a according to this embodiment has four bent portions 132aa-132ad so that it passes through the four corners of the main body housing 100A in a plan view. That is, the guide path 132a according to this embodiment guides the air so that it makes a detour inside the main body housing 100A along the side wall inside the main body housing 100A, rather than guiding the air in a straight line from the intake port 113 to the position of the blower 131 in the shortest distance. The CPAP device 100 according to this embodiment has this configuration in order to lengthen the flow path 132 from the intake port 113 to the position of the blower 131 and reduce the degree to which noise generated by the blower 131 leaks to the outside. In addition, noise can also be reduced by placing a sound-absorbing material on the path and lengthening it.

[0062] The blower installation chamber 132b is an area where the blower 131 is installed, and has, for example, a substantially rectangular shape in the XY plane view. The blower installation chamber 132b is formed such that the flow path cross-sectional area (meaning the cross-sectional area in the direction perpendicular to the air flow direction of the flow path 132; the same applies hereinafter) of the blower installation chamber 132b suddenly expands from the downstream end of the guide path 132a in the XY plane view. More specifically, the blower installation chamber 132b has The width of the flow path in the ±Y direction is formed to suddenly expand from the downstream end of the guide path 132a.

[0063] The blower 131 is disposed in the blower installation chamber 132b such that the suction port 131a (the shaded area in FIG. 6A) of the blower 131 is located at the center of the blower installation chamber 132b in a plan view. In the CPAP device 100 according to this embodiment, in order to ensure a long flow path length of the guide path 132a, the blower 131 is configured to have the suction port 131a opening in a direction intersecting the air guide direction of the guide path 132a (i.e., the Z-axis direction). The blower installation chamber 132b is formed so as to bend the air coming from the guide path 132a in a direction intersecting the guide direction of the guide path 132a, and is formed with an expanded flow path cross-sectional area.

[0064] In this way, air introduced from intake port 113 (black arrow AR1) passes through guide path 132a and blower installation chamber 132b, is drawn into intake port 131a of blower 131 (black arrow AR2), and is sent from an exhaust port (not shown) of blower 131 through air inlet 152a to water tank 151 (humidifier 150A). At this time, when air is drawn into intake port 131a of blower 131, it is drawn from the +Z direction toward the -Z direction.

[0065] In the CPAP device 100 according to this embodiment, in this flow path configuration, first measurement port 164a of differential pressure sensor 164 is disposed in guide path 132a, and second measurement port 164b of differential pressure sensor 164 is disposed in blower installation chamber 132b. Differential pressure sensor 164 is configured to measure the pressure difference of the air flow between the positions of first measurement port 164a and second measurement port 164b.

[0066] The CPAP device 100 according to this embodiment has this configuration in order to enable detection of not only the low-frequency component of the respiratory flow but also the high-frequency component of the respiratory flow by the differential pressure sensor 164. The principle of detecting the high-frequency component of the respiratory flow in the CPAP device 100 according to this embodiment is as shown in FIG.

[0067] That is, in the CPAP device 100 according to this embodiment, the change in the cross-sectional area of ​​the flow path from the induction path 132a to the blower installation chamber 132b is a sudden step-like expansion. As a result, when the airflow enters the blower installation chamber 132b from the induction path 132a, it separates from the wall surface, which causes a pressure loss. The pressure loss caused by the separation of the airflow not only changes the flow velocity of the airflow, but also causes a change in the density of the airflow. Therefore, the differential pressure sensor 164 can use this pressure loss to detect high-frequency components of the change in the airflow volume.

[0068] When detecting the high frequency components of the change in the air flow rate using the differential pressure sensor 164, it is preferable to separate the air flow from the wall surface. When separating the air flow from the wall surface, the change in the flow path cross-sectional area from the guide path 132a to the blower installation chamber 132b does not have to be step-like.

[0069] The first measurement port 164a of the differential pressure sensor 164 is preferably disposed in the guideway 132a at a position that is a predetermined distance away from the connection between the guideway 132a and the blower installation chamber 132b toward the intake port 113. This predetermined distance is, for example, 10 cm to 40 cm. That is, the first measurement port 164a is preferably disposed upstream of the connection between the guideway 132a and the blower installation chamber 132b and at least upstream of the most downstream bent portion 132aa. However, because airflow disturbances often occur near the intake port 113, the first measurement port 164a is preferably disposed closer to the blower 131 (downstream) than the midpoint between the intake port 113 and the blower 131 in the guideway 132a. Furthermore, it is preferable that the position of first measurement port 164a is a position on a straight portion of taxiway 132a, rather than a position on bends 132aa-132ad in taxiway 132a. In other words, first measurement port 164a and second measurement port 164b are arranged on taxiway 132a so as to sandwich bend 132aa therebetween.

[0070] As a result, when the airflow passes through guide path 132a between first measurement port 164a and second measurement port 164b, a pressure loss occurs due to frictional resistance (particularly frictional resistance when passing through bent portion 132aa). This makes it possible to improve the measurement accuracy of differential pressure sensor 164 for low-frequency components of changes in airflow flow rate (i.e., low-frequency components below 10 Hz due to breathing).

[0071] Furthermore, it is more preferable that the second measurement port 164b of the differential pressure sensor 164 be disposed in the blower installation chamber 132b on the opposite side of the connection between the induction path 132a and the blower installation chamber 132b (i.e., near the surface of the blower installation chamber 132b that faces the connection between the induction path 132a and the blower installation chamber 132b). This makes it possible to prevent noise from being introduced into the measurement results due to turbulence in the airflow occurring at the point where the air flows from the induction path 132a into the blower installation chamber 132b.

[0072] 7A and 7B are diagrams showing the arrangement of a differential pressure sensor 164R in a CPAP device 100R according to a comparative example. FIG. 7A shows a plan view of a flow path 132R formed in a flow path case 130R. FIG. 7B also shows a schematic diagram of the arrangement positions of first and second measurement ports 164aR, 164bR of the differential pressure sensor 164R in the flow path 132R. The CPAP device 100R according to the comparative example has a configuration that would be expected when a conventional flow rate measurement method is applied to the CPAP device 100 according to this embodiment.

[0073] The CPAP device 100 according to this embodiment differs from the CPAP device 100R according to the comparative example (see FIGS. 7A and 7B) in that it does not have a resistor RR in the guide path 132a.

[0074] This is because the CPAP device 100 according to this embodiment employs a method for ensuring the pressure difference between the first measurement port 164a and the second measurement port 164b by utilizing the pressure loss that occurs when the airflow separates from the wall surface when it enters the blower installation chamber 132b from the guide path 132a, and the pressure loss due to frictional resistance when the airflow passes through the guide path 132a. Furthermore, this method does not use the resistor RR, and therefore has the additional effect of suppressing a decrease in the output of the blower 131 due to an airflow obstruction caused by the resistor RR.

[0075] <3> summary As described above, respiratory assistance device 100 according to this embodiment includes main body housing 100A having intake port 113 and exhaust port, and forming air flow path 132 from intake port 113 to exhaust port, blower 131 disposed in flow path 132 and generating an airflow to be sent into the patient's airway, and differential pressure sensor 164 measuring the flow rate of air flowing in flow path 132. Flow path 132 guides air from intake port 113 to the position of blower 131. The air conditioner has a guideway 132a and a blower arrangement chamber 132b formed so that the flow path cross-sectional area expands from the downstream end of the guideway 132a, and the differential pressure sensor 164 has a first measurement port 164a arranged in the guideway 132a and a second measurement port 164b arranged in the blower arrangement chamber 132b, and measures the flow rate of the air flow based on the pressure difference of the air flow between the two points of the position of the first measurement port 164a and the position of the second measurement port 164b.

[0076] Therefore, the CPAP device 100 according to this embodiment can capture the patient's respiratory waveform more accurately.

[0077] This makes it possible to appropriately control the operation (i.e., rotation speed) of the blower 131 in accordance with the patient's respiratory flow. Note that the CPAP device 100 may, for example, capture low-frequency components (normal respiratory movement components) and high-frequency components (snoring components) from the respiratory waveform, and control the rotation of the blower 131 based on waveform changes for each of the frequency components.

[0078] The present invention is not limited to the above-described embodiment, but can be applied to various modified embodiments.

[0079] For example, in the above embodiment, the main body housing 100A of the CPAP device 100 is configured by the storage case 110, the flow path case 130, and the base unit 150. However, in order to realize the CPAP device 100 according to the present invention, these do not necessarily have to be separable.

[0080] In the above embodiment, the blower 131 increases the pressure of the air flowing through the flow path 132. However, in order to realize the CPAP device 100 according to the present invention, the blower 131 does not necessarily need to be one that discharges a high-pressure airflow, and may be one that discharges a low-pressure airflow similar to that of a so-called fan.

[0081] The above-described embodiments are merely examples of specific embodiments of the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from the gist or main characteristics thereof.

[0082] At least the following matters will become clear from the description of this specification and the accompanying drawings.

[0083] This specification discloses a respiratory assistance device comprising: a main body housing having an intake port and an exhaust port and forming an air flow path from the intake port to the exhaust port; a blower disposed in the flow path and generating an airflow to be sent into a patient's airway; and a differential pressure sensor disposed to detect the state of the airflow and measuring the differential pressure between a first measurement port and a second measurement port disposed in the flow path, wherein the flow path has a guide path that guides the air from the intake port to the position of the blower, and a blower arrangement chamber formed so that the flow path cross-sectional area expands from the downstream end of the guide path, and the first measurement port of the differential pressure sensor is disposed in the guide path, and the second measurement port of the differential pressure sensor is disposed in the blower arrangement chamber.

[0084] This makes it possible to capture the patient's respiratory waveform more accurately, and also makes it possible to appropriately control the operation of the blower (i.e., the rotation speed) in accordance with the patient's respiratory flow.

[0085] In the respiratory assistance device, it is preferable that the first measurement port is arranged within the guideway at a position a predetermined distance away from the connection point between the guideway and the blower installation chamber toward the intake port.

[0086] This also improves the measurement accuracy of the differential pressure sensor's low-frequency components of changes in airflow (i.e., low-frequency components below 10 Hz caused by breathing), making it possible to capture the patient's breathing waveform more accurately.

[0087] In the respiratory assistance device, the second measurement port is preferably disposed in the blower installation chamber at a position opposite to the connection position between the induction path and the blower installation chamber.

[0088] This prevents noise from being introduced into the measurement results due to turbulence in the airflow at the point where the air flows from the induction path into the blower installation room, thereby enabling a more accurate capture of the patient's respiratory waveform.

[0089] Preferably, the respiratory assistance device further comprises a control unit that controls the rotation speed of the blower based on the respiratory waveform of the patient detected from the measurement result of the differential pressure sensor.

[0090] This makes it possible to appropriately control the operation (i.e., rotation speed) of the blower in accordance with the respiratory flow of the patient.

[0091] In the respiratory assistance device, the guide path preferably guides the air from the intake port to the position of the blower in a long detour within the main body housing.

[0092] This reduces the amount of noise generated by the blower that leaks to the outside.

[0093] Furthermore, in the respiratory assistance device, it is preferable that the blower has an intake port that opens in a direction that intersects with the air guide direction in the guide path, and that the blower installation chamber is formed so as to bend the air coming from the guide path in a direction that intersects with the guide direction.

[0094] This allows the device to be kept large while maintaining a long flow path. This means that an airflow that matches the patient's respiratory flow can be delivered to the patient. Furthermore, the device can be made smaller while reducing noise generated by the device.

[0095] Preferably, the respiratory assistance device further includes an analysis unit that performs frequency analysis on the respiratory waveform of the patient detected from the measurement result of the differential pressure sensor, and obtains signal strength for each frequency as respiratory information.

[0096] This makes it possible to appropriately control the operation (i.e., rotation speed) of the blower in accordance with the respiratory flow of the patient.

[0097] The respiratory assistance device is preferably applied to a CPAP device.

[0098] This allows the respiratory assistance device to be realized in a more suitable manner. [Industrial Applicability]

[0099] The respiratory assistance device according to the present invention makes it possible to capture the patient's respiratory waveform more accurately. [Explanation of symbols]

[0100] 1 patient 10 Mask 20 tubes 100 CPAP device (breathing support device) 100A main body housing 110 Storage Case 112 Tube Connector 113 Air intake 114 Power Connector 120 Circuit Board 122 Control Unit 123 Heating control unit 124 Respiratory waveform analysis section 125 Communications Department 126 Storage section 130 Flow path case 131 Blower 132 Channel 132a taxiway 132aa~132ad Bend part 132b Blower installation room 150 Base 150A humidifier 151 Aquarium 152 Lid 152a Air intake 152b Air outlet 153 Heater 154 AC / AD converter 155 Sheet Metal Components 156 fans 161 filters 162 Temperature and humidity sensor 164 Differential pressure sensor 165 Pressure Sensor 166 Temperature Sensor 168 Temperature Sensor 169 Heater 200 External Systems

Claims

1. a main body housing having an air intake port and an air exhaust port, the main body housing forming an air flow path from the air intake port to the air exhaust port; a blower disposed in the flow path for generating a flow of air for delivery to the patient's airway; a differential pressure sensor disposed to detect the state of the air and measuring a differential pressure between a first measurement port and a second measurement port disposed in the flow path; Equipped with the flow path includes a guide path that guides the air from the intake port to the position of the blower, and a blower installation chamber that is formed so that the flow path cross-sectional area expands from the downstream end of the guide path, the first measurement port of the differential pressure sensor is disposed within the guideway; The second measurement port of the differential pressure sensor is disposed in the blower installation chamber. Breathing support equipment.

2. The device further includes an analysis unit that performs frequency analysis on the respiratory waveform of the patient detected from the measurement result of the differential pressure sensor, and obtains signal strength for each frequency as respiratory information.

10. The respiratory assistance device of claim 1.

3. The analysis unit captures high-frequency components, and the blower is controlled to increase its rotation speed when the analysis unit detects the high-frequency components.

3. The respiratory assistance device of claim 2.

4. The first measurement port is disposed in the taxiway at a position spaced a predetermined distance from a connection between the taxiway and the blower installation chamber toward the intake port.

10. The respiratory assistance device of claim 1.

5. The second measurement port is disposed in the blower installation chamber at a position opposite to the connection position between the induction path and the blower installation chamber.

10. The respiratory assistance device of claim 1.

6. a control unit that controls the rotation speed of the blower based on the respiratory waveform of the patient detected from the measurement result of the differential pressure sensor; 10. The respiratory assistance device of claim 1.

7. The guide path guides the air from the intake port to the position of the blower so as to make a large circuit within the main body housing.

10. The respiratory assistance device of claim 1.

8. the blower has an intake port that opens in a direction intersecting the air guide direction in the guide path, The blower installation chamber is formed so as to bend the air flowing through the induction path in a direction intersecting the induction direction.

8. The respiratory assistance device of claim 7.

9. The respiratory support device according to claim 1, which is applied to a CPAP device.

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