In vivo pressure measuring device

Abstract

The in vivo pressure measuring device, for example, includes a light source that outputs test light, an optical fiber that inputs the test light and at least partially includes a sensor fiber that transmits the test light with a loss of 0.3 dB / m or more, and a light receiving unit that receives the test light after transmission through the sensor fiber. The in vivo pressure acting on the sensor fiber is measured based on the intensity of the test light received by the light receiving unit. The in vivo pressure may also be the pressure of the fluid within the body. The sensor fiber may also be a plastic fiber. The sensor fiber may also have a bend. The sensor fiber may also be insertable into the body.

Description

Technical Field

[0001] The present invention relates to a device for measuring pressure in a living body. Background Art

[0002] Conventionally, an invasive blood pressure monitor such as that disclosed in Patent Document 1 and a non-invasive blood pressure monitor such as that disclosed in Patent Document 2 are known.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-187146

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-028478 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In any type of blood pressure monitor, if it can be made smaller or its structure simplified, it will be beneficial.

[0009] Furthermore, it would be more beneficial if the pressure and force acting in a living body could be measured, not just blood pressure.

[0010] Therefore, one of the objects of the present invention is, for example, to provide a novel and further improved in vivo pressure measuring device.

[0011] Means for solving problems

[0012] The in vivo pressure measuring device of the present invention includes, for example: a light source that outputs test light; an optical fiber that inputs the test light, at least partially including a sensor fiber that transmits the test light with a loss of 0.3 [dB / m] or more; and a light receiving unit that receives the test light after being transmitted within the sensor fiber, and measures the in vivo pressure acting on the sensor fiber based on the intensity of the test light received by the light receiving unit.

[0013] In the in-vivo pressure measuring device, the in-vivo pressure may be a pressure of a fluid in the in-vivo.

[0014] In the in vivo pressure measuring device, the sensor optical fiber may be a plastic fiber.

[0015] In the in vivo pressure measurement device, the sensor optical fiber may have a bent portion.

[0016] In the in vivo pressure measurement device, the sensor optical fiber may be insertable into a living body.

[0017] In the in-vivo pressure measuring device, the sensor optical fiber may measure the pressure of the extracorporeal fluid to which the pressure of the in-vivo fluid has been transmitted.

[0018] The in vivo pressure measuring device may include a flexible supporting member extending along the optical fiber and supporting the optical fiber.

[0019] The in vivo pressure measuring device may include a tubular member that houses the optical fiber.

[0020] In the in vivo pressure measurement device, the tubular member may be flexible.

[0021] The in-vivo pressure measuring device may include a cover covering the sensor optical fiber in a state where the in-vivo fluid or the in-vivo fluid to which the pressure of the in-vivo fluid is transmitted can be introduced.

[0022] In the in-vivo pressure measuring device, the sensor optical fiber may be located outside the body and may measure the pressure of the in-vivo fluid acting indirectly via the body.

[0023] In the in-vivo pressure measuring device, the sensor optical fiber may be arranged between a cuff and the living body, the cuff being located outside the living body and configured to constrict a blood vessel in the living body by internal air pressure and to be able to change the air pressure.

[0024] In the in vivo pressure measuring device, the optical fiber may include the sensor fiber and a delivery fiber connected to the sensor fiber and having a smaller transmission loss than that of the sensor fiber.

[0025] In the in vivo pressure measuring device, at a wavelength of the test light, the sensor fiber may be a single-mode fiber, and the transmission fiber between the sensor fiber and the light source may be a multi-mode fiber.

[0026] In the in vivo pressure measuring device, the sensor optical fiber and the delivery optical fiber may be fusion-connected.

[0027] In the in vivo pressure measurement device, the light receiving unit may receive test light input from one end of the optical fiber and output from the other end of the optical fiber.

[0028] In the in vivo pressure measuring device, the sensor optical fiber may have a core and a cladding surrounding the core, and include a plurality of nanostructures near the interface between the core and the cladding, wherein the cross-sectional diameter of the nanostructure in the cross section perpendicular to the longitudinal direction of the sensor optical fiber is less than 100 [nm].

[0029] In the in vivo pressure measuring device, the nanostructure may be a particle, a tube, or a void.

[0030] In the in vivo pressure measuring device, a concavo-convex structure having a diameter of 5 nm or more and 100 nm or less may be provided on the outer periphery of the sensor optical fiber.

[0031] The in vivo pressure measuring device may include a calculation processing unit configured to obtain the pressure acting on the sensor optical fiber based on the intensity of the test light.

[0032] In addition, the in vivo pressure measuring device of the present invention includes, for example: a light source that outputs test light; an optical fiber that inputs the test light and includes a sensor portion that leaks light due to an applied external force; and a light receiving portion that receives the test light after being transmitted within the sensor portion, and measures the in vivo pressure acting on the sensor portion based on the intensity of the test light received by the light receiving portion.

[0033] In the in vivo pressure measurement device, the transmission loss in the sensor portion may increase as the external force acting on the sensor portion increases.

[0034] Effects of the Invention

[0035] According to the present invention, for example, an improved and novel in vivo pressure measuring device can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is an exemplary schematic configuration diagram of the in vivo pressure measurement device according to the first embodiment.

[0037] Figure 2 This is an exemplary schematic structural diagram of an optical fiber according to an embodiment.

[0038] Figure 3 This is an illustrative and schematic cross-sectional view of a portion of the sensor unit according to the embodiment, taken along the longitudinal direction.

[0039] Figure 4 1 is an illustrative and schematic cross-sectional view of the sensor portion according to the embodiment, taken perpendicularly to the longitudinal direction.

[0040] Figure 5This is a graph showing an example of temporal changes in pressure detection values ​​detected by the biological intraocular pressure measurement device according to the embodiment and a conventional pressure sensor.

[0041] Figure 6 This is an exemplary schematic configuration diagram of the in vivo pressure measurement device according to the second embodiment.

[0042] Figure 7 This is an exemplary schematic configuration diagram of an in vivo pressure measurement device according to a third embodiment.

[0043] Figure 8 This is an exemplary schematic configuration diagram of an in-vivo pressure measurement device according to a modified example of the third embodiment.

[0044] Figure 9 This is an exemplary schematic configuration diagram of an in vivo pressure measurement device according to a fourth embodiment.

[0045] Figure 10 This is an illustrative and schematic cross-sectional view of a portion of the in vivo pressure measurement device according to the fourth embodiment.

[0046] Figure 11 This is an exemplary schematic configuration diagram of the in-vivo pressure measurement device according to the fifth embodiment, and shows a state in which pressure acts on the sensor unit from the living body.

[0047] Figure 12 This is an exemplary schematic configuration diagram of the in-vivo pressure measurement device according to the fifth embodiment, and shows a state in which pressure acts on the sensor portion from the living body.

[0048] Figure 13 This is an illustrative and schematic cross-sectional view perpendicular to the longitudinal direction of a sensor portion according to a modification of the embodiment. DETAILED DESCRIPTION

[0049] The following discloses exemplary embodiments and variations of the present invention. The structures of the embodiments and variations shown below, as well as the actions and results (effects) obtained by these structures, are merely examples. The present invention may also be implemented using structures other than those shown in the following embodiments and variations. In addition, according to the present invention, at least one of the various effects (including derived effects) obtained by the structures can be obtained.

[0050] The embodiment shown below and the modified example possess the same structure. Therefore, according to the structure of each embodiment and the modified example, the same action and effect based on this same structure can be obtained. In addition, in the following description, these same structures are marked with the same reference numerals, and repeated description is sometimes omitted.

[0051] In addition, in this specification, ordinal numbers are indicated for the purpose of distinguishing parts, components, locations, etc., and do not indicate priority or order.

[0052] [First embodiment]

[0053] Figure 1 This is a schematic diagram of a pressure measurement device 10A according to the first embodiment. In this embodiment, the pressure measurement device 10A is an invasive device that measures blood pressure, which is the pressure of a fluid within a living body. It should be noted that blood is an example of a fluid within a living body A, the object of pressure measurement, and may also be referred to as the first fluid. The pressure measurement device 10A is an example of an in vivo pressure measurement device.

[0054] like Figure 1 As shown, the pressure measuring device 10A includes an optical fiber 11 , a tube group 12 , a catheter 13 , a light source 21 , a light receiving unit 22 , and a control unit 30 .

[0055] The longitudinal end 11e1 of the optical fiber 11 is optically connected to the light source 21, and the longitudinal end 11e2 of the optical fiber 11 is optically connected to the light receiving unit 22. Test light emitted from the light source 21 is input into the optical fiber 11 through the end 11e1, propagates through the optical fiber 11 including the sensor unit 11a, and is output from the optical fiber 11 through the end 11e2 to be received by the light receiving unit 22. The end 11e1 is an example of one end, and the end 11e2 is an example of the other end.

[0056] The light source 21 includes, for example, a laser diode, and outputs light having a wavelength of, for example, 400 nm to 500 nm. Alternatively, the light source 21 may intermittently output pulse light at predetermined time intervals.

[0057] The light receiving unit 22 includes, for example, a photodiode, and detects the intensity of light input from the optical fiber 11, that is, the intensity of light that has passed through the sensor unit 11a. The light receiving unit 22 may also be referred to as a detecting unit.

[0058] The control unit 30 can obtain the intensity of light received by the light receiving unit 22. The control unit 30 can also switch between emission and emission stop of the test light in the light source 21, or change the output state of the test light.

[0059] The catheter 13 is provided on the surface of the living body A, and a distal end (not shown) thereof is inserted into the blood vessel V.

[0060] The tube set 12 is filled with a liquid different from blood, such as saline F2. The catheter 13 and the tube set 12 are configured to transmit the blood pressure in the blood vessel V to the saline F2. The saline F2 is an example of an extracorporeal fluid and may also be referred to as a second fluid.

[0061] The tube group 12 includes a tube 12a and a cavity 12b that is expanded compared to the tube 12a. The sensor portion 11a of the optical fiber 11 is inserted into the cavity 12b. Figure 1 As is apparent, the tube set 12 is located outside the living body A. Therefore, in this embodiment, the sensor unit 11a is located outside the living body A. The sensor unit 11a detects the pressure of the physiological saline solution F2, which has been propagated by the pressure of the blood. It should be noted that the tube set 12 may not include the cavity 12b, and the sensor unit 11a may be inserted into the tube 12a.

[0062] Figure 2 1 is a schematic structural diagram of the optical fiber 11. Figure 2 As shown, the optical fiber 11 includes a sensor portion 11a and two delivery optical fibers 11d. The sensor portion 11a is an optical fiber interposed between the two delivery optical fibers 11d. In other words, one delivery optical fiber 11d, the sensor portion 11a as an optical fiber, and the other delivery optical fibers 11d are mechanically and optically connected in series. The transmission loss of the delivery optical fiber 11d is lower than the transmission loss of the sensor portion 11a. The effective relative refractive index difference of the delivery optical fiber 11d is greater than the effective relative refractive index difference of the sensor portion 11a. In addition, at the boundary 11f between the sensor portion 11a and the delivery optical fibers 11d, the sensor portion 11a and the delivery optical fibers 11d are fusion-spliced. The sensor portion 11a is an example of a sensor optical fiber.

[0063] Figure 3 is a cross-sectional view of a portion of the sensor portion 11a along the longitudinal direction, Figure 4 It is a cross-sectional view perpendicular to the longitudinal direction of the sensor portion 11 a.

[0064] from Figure 3 、 4 As is apparent, the sensor portion 11 a includes a core 11 b and a cladding 11 c that surrounds the core 11 b and has a lower refractive index than the core 11 b.

[0065] The diameter of the core 11b and the relative refractive index difference between the core 11b and the cladding 11c are set so that the sensor unit 11a can transmit the test light in single mode. Alternatively, the cladding 11c may be surrounded by a coating (not shown). In this case, the coating is transmissive to the test light.

[0066] As an example, the cladding diameter, i.e., the outer diameter of the core, of the sensor unit 11a and the delivery optical fiber 11d may be the same. Furthermore, the core diameter (outer diameter) of the sensor unit 11a and the delivery optical fiber 11d may be the same or different. As an example, the core diameter of the delivery optical fiber 11d may be larger than the core 11b of the sensor unit 11a. Furthermore, the delivery optical fiber 11d may be a multimode optical fiber that transmits test light in multiple modes.

[0067] The sensor unit 11a and the optical fiber 11d are made of, for example, a synthetic resin material transparent to test light, such as methacrylic resin or fluororesin, so-called plastic fibers. However, this is not limiting; the sensor unit 11a and the optical fiber 11d may also be glass fibers made of quartz glass. Furthermore, the sensor unit 11a and the optical fiber 11d may be made of different materials.

[0068] In addition, if Figure 3 、 4 As shown, the sensor portion 11a may include a plurality of nanostructures 11p near the interface between the core 11b and the cladding 11c. However, this distribution of the nanostructures 11p is only an example, and the nanostructures 11p may also exist within the sensor portion 11a over the entire radial range spanning the cladding 11c. The nanostructures 11p may each include fillers (e.g., particles such as microparticles or cylindrical tubes), voids (e.g., tiny spaces of air other than tubes or microparticles), or at least two of these examples. The cross-sectional diameter of the nanostructures 11p in a cross section perpendicular to the longitudinal direction of the sensor portion 11a may be, for example, 100 nm or less. In this case, the loss of the sensor portion 11a is likely to increase compared to a case where no fillers or voids are included. It should be noted that the fillers and voids may also be included in greater quantities in the cladding 11c than in the core 11b of the sensor portion 11a.

[0069] Through intensive research, the inventors have come to the following conclusion: In the sensor portion 11a having the aforementioned structure, the test light is scattered by the nanostructures 11p. Consequently, the test light is less likely to be confined within the core 11b than in a structure without the nanostructures 11p. In other words, the test light is more likely to leak from the core 11b. Furthermore, they found that in this case, the greater the external force acting on the sensor portion 11a, the greater the leakage of the test light from the sensor portion 11a. In other words, the greater the transmission loss in the sensor portion 11a. Furthermore, they found that in the sensor portion 11a where the test light is more likely to leak from the core 11b, the transmission loss changes more sensitively to the external force applied. As an example, they found that this characteristic becomes significant when the transmission loss for the test light in the sensor portion 11a is 0.3 dB / m or greater. This is because if the transmission loss is 0.3 [dB / m] or more, light leaks outside the cladding 11c and light-sensitively reacts to changes in the nanostructure 11p near the cladding 11c caused by external pressure, significantly affecting the transmission loss.

[0070] Due to the aforementioned characteristics of the sensor unit 11a, the control unit 30 can calculate the pressure of the physiological saline solution F2 in the sensor unit 11a corresponding to the light intensity received by the light receiving unit 22, and further calculate the blood pressure, i.e., the blood pressure, based on the correlation between the light intensity received by the light receiving unit 22 and the pressure acting on the sensor unit 11a, which has been previously obtained through experiments. The control unit 30 is an example of a calculation processing unit.

[0071] In addition, if Figure 2 As shown, the sensor portion 11a has a curved portion 11a1 that folds back in a U-shape. The curved portion 11a1 can also be referred to as a bend or a folded portion. The inventors' extensive research has revealed that the sensor portion 11a preferably has a length L of 1 cm to 4 cm, and a curvature radius R of the curved portion 11a1 (the radius of the central axis of the sensor portion 11a) of 50 μm to 200 μm.

[0072] Figure 5 This is a graph showing an example of the temporal changes in the pressure values ​​detected by the pressure measuring device 10A of this embodiment and the pressure values ​​detected by a conventional pressure sensor. This graph shows the results of measuring the pressure of a test fluid in an experimental device that can schematically generate pressure changes in the test fluid equivalent to changes in blood pressure due to heartbeats. Figure 5 As can be seen, the pressure measurement device 10A of this embodiment, represented by the solid line, and the conventional pressure sensor, represented by the dashed line, show good agreement in the detected values ​​of the test fluid pressure. The inventors have experimentally confirmed that the pressure measurement device 10A of this embodiment, as shown in this example, achieves measurement performance equivalent to or superior to that of conventional pressure sensors.

[0073] As described above, in this embodiment, the light receiving unit 22 receives the test light emitted from the light source 21 and transmitted through the optical fiber 11, which includes the sensor unit 11a (sensor fiber). The greater the external force, such as the fluid pressure, acting on the sensor unit 11a, the greater the transmission loss of the test light in the sensor unit 11a. The control unit 30 measures the blood pressure (in vivo fluid pressure) acting on the sensor unit 11a based on the intensity of the test light received by the light receiving unit 22.

[0074] According to such a configuration, the pressure measuring device 10A can be realized with a more compact and simpler configuration based on optical fibers.

[0075] In addition, as in this embodiment, the sensor portion 11a may be made of plastic fiber.

[0076] This configuration allows, for example, a more flexible configuration of the sensor portion 11a, thereby further increasing the ratio of the increase in test light transmission loss to the increase in fluid pressure in the sensor portion 11a, i.e., the rate of increase. In other words, this configuration improves the sensitivity of the sensor portion 11a in detecting fluid pressure.

[0077] In addition, as in the present embodiment, the sensor unit 11 a may be an optical fiber that transmits test light with a loss of 0.3 [dB / m] or more.

[0078] In addition, as in the present embodiment, the sensor portion 11 a may include a bent portion 11 a 1 .

[0079] In addition, as in the present embodiment, the sensor portion 11 a may include a plurality of nanostructures 11 p .

[0080] In the present embodiment, the transmission optical fiber 11 d between the sensor unit 11 a and the light source 21 may be a multimode optical fiber, and the sensor unit 11 a may be a single-mode optical fiber.

[0081] According to such a configuration, for example, the test light is more likely to leak from the sensor portion 11 a , and thus the detection sensitivity of the fluid pressure by the sensor portion 11 a can be improved.

[0082] As in the present embodiment, the light receiving unit 22 may receive test light input from the light source 21 to the optical fiber 11 via the end 11e1 (one end) and output from the end 11e2 (the other end) via the sensor unit 11a.

[0083] According to such a configuration, for example, compared to a configuration in which the light receiving unit 22 receives light reflected at one end of the optical fiber 11 , the intensity of received light can be increased, and thus the measurement accuracy can be further improved.

[0084] In addition, in the present embodiment, the sensor unit 11 a measures the pressure of the physiological saline solution F2 (extracorporeal fluid) to which the blood pressure (pressure of the intracorporeal fluid) is transmitted.

[0085] The configuration of this embodiment can be applied to an invasive blood pressure measurement device that indirectly measures the pressure of a fluid in a living body via the fluid outside the living body using the sensor unit 11 a located outside the living body.

[0086] [Second embodiment]

[0087] Figure 6This is a schematic diagram of a portion of a pressure measurement device 10B according to a second embodiment, and is a cross-sectional view along the longitudinal direction of an optical fiber 11 within a blood vessel V. Similar to the first embodiment, the optical fiber 11 of this embodiment is optically connected to a light source 21 and a light receiving unit 22. Specifically, in this embodiment, test light input from the light source 21 to the optical fiber 11 also propagates within the optical fiber 11, including the sensor unit 11a, and is received by the light receiving unit 22. The control unit 30 calculates the pressure acting on the sensor unit 11a based on the intensity of the test light received by the light receiving unit 22.

[0088] like Figure 6 As shown, in this embodiment, the optical fiber 11 is inserted into the blood vessel V. In this configuration, the higher the pressure of the fluid in the blood vessel V, namely, the blood F1, the greater the transmission loss of the test light in the sensor portion 11a. The blood F1 is an example of a fluid in the body and may also be referred to as a first fluid.

[0089] It should be noted that, through intensive research by the inventors, it has been found that, in the pressure measuring device 10B of the present embodiment, regarding the sensor portion 11a, the length L of the sensor portion 11a (see Figure 2 ) is preferably 1 [cm] or more and 4 [cm] or less, and the curvature radius R of the curved portion 11a1 (the radius of the central axis of the sensor portion 11a, see Figure 2 ) is preferably 50 [μm] or more and 200 [μm] or less. Such a region of curvature radius R is a region where bending loss increases sensitively to pressure, thereby further improving the sensor sensitivity to pressure.

[0090] This embodiment also provides the same effects as those of the first embodiment. The pressure measurement device 10B of this embodiment can be applied to an invasive blood pressure measurement device that directly measures the pressure of a fluid in a living body using the sensor unit 11a located in the living body.

[0091] [Third embodiment]

[0092] Figure 7 This is a schematic structural diagram of a portion of a pressure measuring device 10C according to a third embodiment, and is a cross-sectional view taken along the longitudinal direction of the optical fiber 11. The optical fiber 11 of this embodiment is optically connected to the light source 21 and the light receiving unit 22, similarly to the first embodiment described above. That is, in this embodiment, the test light input from the light source 21 to the optical fiber 11 is also transmitted within the optical fiber 11 including the sensor unit 11a and received by the light receiving unit 22. The control unit 30 calculates the pressure acting on the sensor unit 11a based on the intensity of the test light received by the light receiving unit 22. Furthermore, the sensor unit 11a of this embodiment is inserted into the blood vessel V, similarly to the second embodiment described above.

[0093] like Figure 7 As shown, in this embodiment, the pressure measuring device 10C includes a tubular member 14 that surrounds the optical fiber 11. In other words, the tubular member 14 houses the optical fiber 11 within the tubular member. The tubular member 14 surrounds both the outgoing path and the return path of the optical fiber 11 to the sensor unit 11a, with the sensor unit 11a exposed from the distal end of the tubular member 14. The tubular member 14 protects the optical fiber 11.

[0094] The optical fiber 11 passes through the fixing member 14a. The fixing member 14a positions the optical fiber 11 and the tubular member 14 at a predetermined relative position. In this embodiment, the fixing member 14a, for example, fixes the optical fiber 11 and the tubular member 14 in position, and at least at the position where the fixing member 14a is provided, the optical fiber 11 is separated from the peripheral wall of the tubular member 14, and the outgoing path and the returning path of the optical fiber 11 are separated from each other. It should be noted that Figure 7 In the example shown, the pressure measuring device 10C includes only one fixing member 14a, but the present invention is not limited thereto. The pressure measuring device 10C may include a plurality of fixing members 14a arranged at intervals along the longitudinal direction of the tubular member 14. The fixing member 14a is, for example, an adhesive, but the present invention is not limited thereto.

[0095] Furthermore, the tubular member 14 has flexibility and elasticity. Therefore, with this structure, for example, by appropriately setting the specifications of the tubular member 14, the subassembly comprising the tubular member 14 and the optical fiber 11 can be given appropriate elasticity, thereby enabling appropriate followability along the blood vessel V. This facilitates insertion and removal of the sensor portion 11a into and from the blood vessel V. The tubular member 14 is made of, for example, a metal material or a synthetic resin material. The tubular member 14 is also an example of a flexible supporting member that supports the optical fiber 11.

[0096] This embodiment provides the same effects as those of the first embodiment. The pressure measurement device 10C of this embodiment can be applied to an invasive blood pressure measurement device that directly measures the pressure of a fluid in a living body using the sensor unit 11a located in the living body.

[0097] [Modification of the Third Embodiment]

[0098] Figure 8This is a schematic structural diagram of a portion of a pressure measuring device 10D according to a modified example of the third embodiment, and is a cross-sectional view taken along the longitudinal direction of the optical fiber 11. The optical fiber 11 of this modified example is optically connected to the light source 21 and the light receiving unit 22, similarly to the first embodiment described above. That is, in this modified example, the test light input from the light source 21 to the optical fiber 11 is also transmitted within the optical fiber 11 including the sensor unit 11a and received by the light receiving unit 22. The control unit 30 calculates the pressure acting on the sensor unit 11a based on the received light intensity of the test light in the light receiving unit 22. Furthermore, the sensor unit 11a of this modified example is inserted into the blood vessel V, similarly to the third embodiment described above.

[0099] like Figure 8 As shown, in this modified example, the cover 14c, which is the front end portion (part) of the tubular member 14D, covers the sensor portion 11a. However, an opening 14b is provided on the peripheral wall (side wall) of the cover 14c. As a result, the blood F1 introduced into the cover 14c from the blood vessel V through the opening 14b comes into contact with the sensor portion 11a. In other words, the sensor portion 11a is located in the blood. In addition, the fixing member 14a divides the interior of the tubular member 14 into a space S1 and a space S2 opened by the opening 14b. At least a portion of the sensor portion 11a is arranged in the space S2. According to such a structure, the optical fiber 11 and the sensor portion 11a can be protected together by the tubular member 14D. It should be noted that the cover 14c can also be composed of a member different from the tubular member 14 and mounted on the tubular member 14.

[0100] The pressure measurement device 10D of this modified example can be applied to an invasive blood pressure measurement device that directly measures the pressure of a fluid in a living body using the sensor unit 11 a located in the living body.

[0101] [Fourth embodiment]

[0102] Figure 9 This is a schematic diagram of a pressure measurement device 10E according to a fourth embodiment, and is a top view showing the device attached to the outside of a living body A. Similar to the first embodiment, the optical fiber 11 of this embodiment is optically connected to the light source 21 and the light receiving unit 22. Specifically, in this embodiment, the test light input from the light source 21 to the optical fiber 11 is also transmitted through the optical fiber 11, including the sensor unit 11a, and is received by the light receiving unit 22. The control unit 30 calculates the pressure acting on the sensor unit 11a based on the intensity of the test light received by the light receiving unit 22.

[0103] like Figure 9 As shown, in this embodiment, the sensor portion 11 a is disposed on the outer skin of a living body A such as an arm, together with the pad 15 and the cuff 16 .

[0104] The spacer 15 is flexible and sheet-like in shape. The spacer 15 is placed in contact with the outer skin of the organism A. The sensor portion 11a (optical fiber 11) is positioned on the side of the spacer 15 opposite the outer skin of the organism A. That is, the spacer 15 is sandwiched between the sensor portion 11a and the outer skin of the organism A. The sensor portion 11a is secured to the spacer 15 using, for example, an adhesive.

[0105] The cuff 16 is wrapped around the living body A, for example, the arm, so as to cover the spacer 15 and the sensor portion 11 a .

[0106] Furthermore, the sensor portion 11a is bent multiple times via a plurality of bent portions 11a1. With such a structure, the detectable area is expanded.

[0107] Figure 10 FIG is a cross-sectional view of the pressure measuring device 10E perpendicular to the gasket 15. Figure 10 As shown, a gasket 15, a sensor unit 11a, and a cuff 16 are sequentially stacked on the outer skin of a living body A. The sensor unit 11a is disposed between the gasket 15 and the cuff 16. The gasket 15 and the sensor unit 11a may be fixed to the cuff 16 by adhesive or the like, or not.

[0108] In the cuff 16, a space S3 capable of accommodating a gas G, such as air, is provided between a sheet 16a close to the organism A and a sheet 16a far from the organism A. The space S3 is connected to an electric pump and an electric valve, not shown. The cuff 16 is configured so that the pressure of the gas G in the space S3 can be changed by controlling these electric pumps and electric valves. Specifically, the cuff 16 is configured, for example, so that after increasing the pressure of the gas G in the space S3, the pressure can be gradually reduced over time. According to such a structure, the control unit 30 can obtain the maximum blood pressure and the minimum blood pressure based on the detection value of the sensor unit 11a or the temporal change of the blood pressure pulsation obtained based on the detection value, for example, by the well-known oscillometric measurement method in the sphygmomanometer using the cuff 16.

[0109] This embodiment also provides the same effects as those of the first embodiment. The pressure measurement device 10E of this embodiment can be applied to a non-invasive blood pressure measurement device that indirectly measures the pressure of a fluid in a living body through a living body A using a sensor unit 11a located outside the living body.

[0110] [Fifth embodiment]

[0111] Figure 11 、 12This is a schematic diagram of a pressure measurement device 10F according to the fifth embodiment. The pressure measurement device 10F does not measure the pressure of the fluid within a living body A, but rather measures the pressure acting on the sensor portion 11a of the optical fiber 11 from the valve portion Va of the living body A, that is, the pressure exerted on a part within the living body. The valve portion Va has a narrowed portion (throat), and the sensor portion 11a penetrates this narrowed portion. The valve portion Va is, for example, a valve in the heart or the pylorus of the stomach. Figure 11 The stenosis is greatly expanded and no pressure is applied to the sensor portion 11a from the valve portion Va, that is, the biological body A. Figure 12 The narrowed portion is narrowed to a small extent, and a pressure is applied from the valve portion Va to the sensor portion 11a. Figure 12 In the state, the outer periphery of the sensor part 11a is recessed due to the force received from the valve part Va. Figure 11 Compared to the state in which the test light is not in the normal state, the leakage of the test light from the sensor portion 11a increases, and the transmission loss of the test light in the sensor portion 11a increases. Therefore, based on the correlation between the light intensity in the light receiving portion 22 and the pressure acting on the sensor portion 11a from the valve portion Va, which has been previously obtained through experiments, the control portion 30 can calculate the pressure acting on the sensor portion 11a corresponding to the light intensity in the light receiving portion 22. It should be noted that the pressure measuring device 10F can also measure the force (load) acting on the sensor portion 11a from the valve portion Va. That is, in this embodiment, the pressure measuring device 10F can also function as a force measuring device (load measuring device) within a living body.

[0112] [Modification of the sensor section]

[0113] Figure 13 FIG is a cross-sectional view perpendicular to the longitudinal direction of the sensor portion 11a according to a modified example of the embodiment. Figure 13 As shown, a concave-convex structure including concave or convex parts may also be provided on the periphery 11a2 of the sensor part 11a, that is, the periphery 11a2 of the cladding 11c. The concave-convex structure may also be referred to as a structural fluctuation. By setting the size of the concave-convex structure, such as the length in the longitudinal direction of the concave-convex structure, the spacing, the height difference in the radial direction, etc., to appropriate values, the transmission loss of the sensor part 11a for the test light can be made 0.3 [dB / m] or more. Through in-depth research by the inventors, it was found that the size of the concave and convex of the concave-convex structure is preferably greater than 5 [nm] and less than 100 [nm]. Figure 13In FIG, as an example of an indicator of the size of the concavo-convex structure, the deviation h of the average radius of the outer periphery 11a2 of the sensor portion 11a in a cross section perpendicular to the longitudinal direction relative to the circumference C is shown. This deviation h is also preferably greater than 5 [nm] and less than 100 [nm]. It should be noted that the concavo-convex structure can also be provided on the outer periphery of the fiber core 11b. In addition, in this modified example, the sensor portion 11a can also be made of, for example, plastic fiber.

[0114] The above examples illustrate the embodiments and modifications of the present invention, but the above embodiments and modifications are examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other ways, and various omissions, substitutions, combinations, and changes can be made without departing from the gist of the invention. In addition, the specifications such as various structures and shapes (structure, type, direction, type, size, length, width, thickness, height, quantity, configuration, position, material, etc.) can be appropriately changed for implementation.

[0115] For example, the configurations of the above-described embodiment and modified examples can also be applied to measuring the pressure of in vivo fluids other than blood, or measuring the pressure received by in vivo sites other than valves such as heart valves and the pylorus of the stomach.

[0116] Furthermore, the support member is not limited to a tubular member and may be, for example, a flexible rod-shaped member. In this case, the optical fiber may extend linearly or helically along the outer circumference of the support member. Furthermore, the optical fiber may be housed in a linear or helical groove provided on the outer circumference of the support member.

[0117] Alternatively, optical fibers with different mode transmission states can be used for the sensor unit and the delivery fiber, so that mode conversion occurs at the connection point (boundary) between the sensor unit (sensor fiber) and the delivery fiber between the sensor unit and the light source. In this case, the mode conversion at the connection point depends on the external force, and the state of mode mismatch also depends on the external force. As a result, the degree of test light leakage in the sensor unit becomes more sensitive to external forces, further improving the sensor unit's sensitivity to in vivo pressure.

[0118] Industrial Applicability

[0119] The present invention can be used in an in vivo pressure measuring device.

[0120] Description of reference numerals:

[0121] 10A-10F…Pressure measuring device (in vivo pressure measuring device)

[0122] 11…Fiber optics

[0123] 11a…Sensor unit (sensor optical fiber)

[0124] 11a1…Bend

[0125] 11a2…periphery

[0126] 11b…fiber core

[0127] 11c…cladding

[0128] 11d…delivery optical fiber

[0129] 11e1…end (one end)

[0130] 11e2…end (other end)

[0131] 11f…Border

[0132] 11p…Nanostructure

[0133] 12…tube group

[0134] 12a...tube

[0135] 12b…Chamber

[0136] 13…catheter

[0137] 14, 14D ... tubular member (support member)

[0138] 14a…Fixed component

[0139] 14b…opening

[0140] 14c...hood

[0141] 15…gasket

[0142] 16…cuff

[0143] 16a…sheet

[0144] 21…Light source

[0145] 22…Light receiving part

[0146] 30…Control unit (processing unit)

[0147] A…organism

[0148] C…circumference

[0149] F1…blood (fluid in the body)

[0150] F2…Physiological saline (extracorporeal fluid)

[0151] G…Gas

[0152] h…deviation

[0153] L…length

[0154] R…radius of curvature

[0155] S1~S3…space

[0156] V…blood vessels

[0157] Va…valve part.

Claims

1. A device for measuring pressure in a living body, wherein: The in vivo pressure measuring device comprises: a light source that outputs a test light; an optical fiber that inputs the test light and at least partially includes a sensor fiber that transmits the test light with a loss of 0.3 [dB / m] or more; as well as a light receiving unit for receiving the test light transmitted through the sensor optical fiber; Based on the intensity of the test light received by the light receiving unit, the pressure in the living body acting on the sensor optical fiber is measured. The sensor optical fiber has a core and a cladding surrounding the core, and includes a plurality of nanostructures near the interface between the core and the cladding. The nanostructures in the cladding are more numerous than the nanostructures in the core.

2. The in vivo pressure measuring device according to claim 1, wherein The pressure in the living body is the pressure of the fluid in the living body.

3. The in vivo pressure measuring device according to claim 1 or 2, wherein: The sensor optical fiber is a plastic fiber.

4. The in vivo pressure measuring device according to claim 1 or 2, wherein: The sensor optical fiber has a bend.

5. The in vivo pressure measuring device according to claim 1 or 2, wherein: The sensor optical fiber can be inserted into a living body.

6. The in vivo pressure measuring device according to claim 1 or 2, wherein: The sensor optical fiber measures the pressure of the extracorporeal fluid to which the pressure of the intracorporeal fluid is transmitted.

7. The in vivo pressure measuring device according to claim 1 or 2, wherein: The in vivo pressure measurement device includes a flexible supporting member extending along the optical fiber and supporting the optical fiber.

8. The in vivo pressure measuring device according to claim 1 or 2, wherein: The in vivo pressure measuring device includes a tubular member that houses the optical fiber.

9. The in vivo pressure measuring device according to claim 8, wherein The tubular member has flexibility.

10. The in vivo pressure measuring device according to claim 1 or 2, wherein: The in-vivo pressure measuring device includes a cover that covers the sensor optical fiber in a state where in-vivo fluid or extra-vivo fluid to which the pressure of the in-vivo fluid is transmitted can be introduced.

11. The in vivo pressure measuring device according to claim 1 or 2, wherein: The sensor optical fiber is located outside the body and measures the pressure of the fluid in the body that acts indirectly through the body.

12. The in vivo pressure measuring device according to claim 11, wherein The sensor optical fiber can be arranged between a cuff and a living body. The cuff is located outside the living body and is configured to constrict blood vessels in the living body by internal air pressure and to change the air pressure.

13. The in vivo pressure measuring device according to claim 1 or 2, wherein: The optical fiber includes the sensor fiber and a delivery fiber connected to the sensor fiber and having a smaller transmission loss than that of the sensor fiber.

14. The in vivo pressure measuring device according to claim 13, wherein At the wavelength of the test light, the sensor fiber is a single-mode fiber, and the delivery fiber between the sensor fiber and the light source is a multi-mode fiber.

15. The in vivo pressure measuring device according to claim 13, wherein The sensor optical fiber is fusion-connected to the delivery optical fiber.

16. The in vivo pressure measuring device according to claim 1 or 2, wherein: The light receiving unit receives test light input from one end of the optical fiber and output from the other end of the optical fiber.

17. The in vivo pressure measuring device according to claim 1 or 2, wherein: The nanostructure has a cross-sectional diameter of 100 nm or less in a cross section perpendicular to the longitudinal direction of the sensor optical fiber.

18. The in vivo pressure measuring device according to claim 17, wherein The nanostructures are particles, tubes or voids.

19. The in vivo pressure measuring device according to claim 1 or 2, wherein: A concavo-convex structure having a diameter of 5 nm or more and 100 nm or less is provided on the outer periphery of the sensor optical fiber.

20. The in vivo pressure measuring device according to claim 1 or 2, wherein The in vivo pressure measurement device includes a calculation processing unit configured to obtain the pressure acting on the sensor optical fiber based on the intensity of the test light.

21. A device for measuring pressure in a living body, wherein: The in vivo pressure measuring device comprises: a light source that outputs a test light; an optical fiber that inputs the test light and includes a sensor portion that leaks light due to an applied external force; and a light receiving unit that receives the test light transmitted through the sensor unit, Based on the intensity of the test light received by the light receiving unit, the pressure in the living body acting on the sensor unit is measured; The sensor portion includes a core and a cladding surrounding the core, and includes a plurality of nanostructures near an interface between the core and the cladding. The nanostructures in the cladding are more numerous than the nanostructures in the core.

22. The in vivo pressure measuring device according to claim 21, wherein The greater the external force acting on the sensor portion, the greater the transmission loss in the sensor portion.

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