LIGHT INTRODUCTION DEVICE AND STERILIZATION SYSTEM

A light introduction device (3) has an inner cavity allowing passage of at least one of a substance introduced into a human body or a substance discharged from the human body. Light is introduced from part of an outer surface of a section, which is arranged outside the human body, of a catheter (2) as a medical conduit having a light-permeable thick portion.

TECHNICAL FIELD

The present invention relates to a light introduction device and a sterilization system.

BACKGROUND ART

An instantaneous sterilization/disinfection unit configured to sterilize, using light, a catheter inserted into a patient and/or a skin therearound is disclosed (see Patent Literature 1 below). In the instantaneous sterilization/disinfection unit, a light source configured to emit ultraviolet light (UV) is arranged above an insertion section of the catheter and/or the catheter around the insertion section, and the light source irradiates the insertion section of the catheter and/or the periphery of the insertion section with the UV.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, in the instantaneous sterilization/disinfection unit of Patent Literature 1 above, tendency shows that a catheter portion surrounded by a human tissue is less irradiated with the UV emitted from the outside of the patient. Specifically, tendency shows that a back side of the catheter portion surrounded by the human tissue on the opposite side of the side provided with the light source is less irradiated with the ultraviolet light. For this reason, there are concerns that deactivation of bacteria present between the catheter and the human tissue is insufficient, and a demand for deactivation has been increased. Moreover, a demand for deactivation of bacteria present in liquid introduced into the catheter has been also increased. However, in the instantaneous sterilization/disinfection unit of Patent Literature 1 above, the patient is merely directly irradiated with light, and the bacteria present between the catheter and the human tissue and the bacteria present in the liquid in the catheter cannot be deactivated. Thus, a device configured to irradiate bacteria with light through a medical conduit to deactivate the bacteria has been demanded.

Thus, the present invention provides a light introduction device and a sterilization system configured so that bacteria can be irradiated with light through a medical conduit to enhance a sterilization effect against a substance contacting the medical conduit.

The light introduction device of the present invention is characterized by including an inner cavity allowing passage of at least one of a substance introduced into a human body or a substance discharged from the human body. Light is introduced from part of an outer surface of a section, which is arranged outside the human body, of a medical conduit having a light-permeable thick portion.

According to the light introduction device, the light is introduced into the medical conduit having the light-permeable thick portion, and therefore, the light can propagate to bacteria present in a substance contacting the medical conduit through the medical conduit. Thus, the bacteria present in the substance contacting the medical conduit can be deactivated by the light. In this manner, according to the light introduction device of the present invention, a sterilization effect against the substance contacting the medical conduit can be enhanced. Note that the medical conduit may be directly connected to the human body, or may be indirectly connected to the human body through, e.g., other medical conduits or an infusion needle.

Moreover, the above-described light introduction device preferably includes a light guide member surrounding the outer surface of the section of the medical conduit arranged outside the human body. One end portion of the light guide member facing one opening end side of the medical conduit is preferably diagonally inclined toward the medical conduit as extending toward one opening end side of the medical conduit, and the light entering from the other end side of the light guide member facing the other opening end side of the medical conduit is preferably entered to the medical conduit diagonally to a longitudinal direction of the medical conduit.

The light entered diagonally to the longitudinal direction of the medical conduit easily propagates in the longitudinal direction in the thick portion of the medical conduit as compared to light entered perpendicularly to the longitudinal direction of the medical conduit. Thus, the medical conduit itself serves as a waveguide, and the light can propagate to the substance contacting the medical conduit at a position apart from the light introduction device. Thus, according to the light introduction device, the sterilization effect against the substance contacting the medical conduit at the position apart from the light introduction device can be enhanced. For example, in a case where the medical conduit is arranged from the outside to the inside of the human body, when the opening end of the medical conduit on the inside of the human body is one opening end, bacteria interposed between the medical conduit and the human tissue can be, without passage through the human tissue, directly irradiated with the light through the medical conduit in a state in which the medical conduit is arranged in the human body. Thus, the bacteria interposed between the human tissue and a portion of the medical conduit surrounded by the human tissue can be deactivated such that the amount of the bacteria is decreased.

Further, the light guide member and the medical conduit preferably closely contact each other.

In this case, the amount of light introduced into the medical conduit through the light guide member can be increased as compared to a case where a clearance is formed between the light guide member and the medical conduit.

In addition, the above-described light introduction device preferably includes an optical fiber allowing entrance of the light from the outer surface of the section of the medical conduit arranged outside the human body. One end portion of the optical fiber preferably has an inclined surface inclined with respect to the center axis of the optical fiber, and is preferably arranged closer to the medical conduit as extending toward one opening end side of the medical conduit. The inclined surface preferably faces an outer surface of the medical conduit.

In this case, the amount of light entered to the medical conduit from the outer surface of the medical conduit can be increased as compared to an optical fiber configured such that an end surface of the optical fiber is arranged as described above perpendicularly to the center axis. Moreover, the direction of the light entered to the medical conduit is inclined with respect to the longitudinal direction of the medical conduit so that the inclined surface can easily contact the medical conduit. Thus, a loss of the light emitted from the optical fiber can be reduced, and such light can enter the medical conduit. As described above, the direction of the light entered to the medical conduit is inclined with respect to the longitudinal direction of the medical conduit. Thus, the light can propagate to the substance contacting the medical conduit at the position apart from the light introduction device as described above, and the sterilization effect against the substance contacting the medical conduit at the position apart from the light introduction device can be enhanced.

In this case, the angle between a line perpendicular to the inclined surface and the center axis of the optical fiber is preferably equal to or greater than 46 degrees, and the outer surface of the medical conduit and the inclined surface are preferably parallel to each other.

Generally, the refractive index of the optical fiber is higher than the refractive index of the medical conduit. Thus, according to the above-described configuration, the entrance angle of light entered to the outer surface of the medical conduit from the inclined surface of the optical fiber can be equal to or greater than 46 degrees. Thus, the amount of total reflection of the light entered from the outer surface to the thick portion of the medical conduit on an inner surface of the medical conduit can be increased as compared to a case where the entrance angle of light entered to the outer surface of the medical conduit is less than 46 degrees. Thus, the light can easily propagate, through the medical conduit, to the substance contacting the medical conduit at the position apart from the light introduction device.

Moreover, the light introduction device preferably further includes a fixing member configured to fix multiple optical fibers. The fixing member preferably has an arrangement surface arranged on the outer surface of the medical conduit, and preferably covers one end portion of each optical fiber such that an inclined surface of each optical fiber is exposed from an arrangement surface side.

In this case, the arrangement surface side of the fixing member fixing the multiple optical fibers is defined as an emission side of the light propagating in each optical fiber. Thus, the inclined surfaces of the optical fibers can easily face the outer surface of the medical conduit without separation of the multiple optical fibers.

Further, the fixing member preferably has flexibility, and the inclined surfaces of the multiple optical fibers are preferably arranged at intervals in one direction.

In this case, in a state in which the light is dispersed in a predetermined direction, the light can enter the medical conduit, and concentration of the light entering the medical conduit can be reduced. Moreover, the fixing member has the flexibility. Thus, the direction of arrangement of the optical fibers is coincident with a circumferential direction of the outer surface of the medical conduit so that the ultraviolet light can be introduced into the medical conduit from the circumferential direction. Thus, non-uniform introduction of the light in the circumferential direction of the medical conduit can be reduced. For example, in a case where the medical conduit is arranged from the outside to the inside of the human body, the light can be easily released from the circumferential direction of the medical conduit to the human tissue through the medical conduit, and as a result, a light irradiation region for the human tissue can be more expanded. Moreover, in a case where liquid is, for example, introduced into the inner cavity of the medical conduit, the liquid can be irradiated with the light from the circumferential direction of the medical conduit. Thus, the sterilization effect can be more enhanced.

In addition, the inclined surface of each optical fiber preferably closely contacts the outer surface of the medical conduit.

In this case, the loss of the light emitted from the optical fiber can be reduced, and the light can enter the medical conduit.

Moreover, the light preferably has a peak wavelength in a wavelength band of 270 nm to 340 nm.

In this case, the bacteria interposed between the medical conduit and the human tissue can be irradiated with light having a wavelength with a high sterilization ability, or the bacteria present in the liquid introduced into the medical conduit can be irradiated with such light. Thus, the sterilization effect can be more enhanced.

Further, the sterilization system of the present invention is characterized by including a medical conduit including an inner cavity allowing passage of at least one of a substance introduced into a human body or a substance discharged from the human body and including a light-permeable thick portion, and any of the above-described light introduction devices.

According to this sterilization system, the light can be introduced from the light introduction device into the medical conduit, and can propagate to the bacteria present in the substance contacting the medical conduit to deactivate the bacteria. Thus, according to the sterilization system of the present invention, the sterilization effect against the substance contacting the medical conduit can be enhanced.

In addition, liquid is preferably introduced into the inner cavity of the medical conduit.

The liquid introduced into the inner cavity of the medical conduit is the substance contacting an inner wall of the medical conduit, and the light can propagate in the substance through the medical conduit. Thus, bacteria present in the liquid can be deactivated such that the amount of the bacteria is decreased. When such liquid is the liquid introduced into the human body, the liquid with a reduced bacterium amount can be introduced into the human body.

Moreover, the medical conduit is preferably arranged from the outside to the inside of the human body.

The medical conduit itself having the light-permeable thick portion can serve as the waveguide. Thus, in a state in which part of the medical conduit is arranged in the human body, the bacteria interposed between the medical conduit and the human tissue can be irradiated with the light through the medical conduit. Thus, as compared to a case where the light is irradiated from the outside of the human body by way of the human tissue, the bacteria interposed between the human tissue and the medical conduit portion surrounded by the human tissue can be deactivated such that the amount of the bacteria is decreased. Note that in the case of introducing the liquid into the inner cavity of the medical conduit, the liquid can also serve as part of the waveguide.

In this case, at least part of the section of the medical conduit surrounded by the human tissue is preferably configured such that a light transmission for a wavelength band of 270 nm to 340 nm per millimeter in length is equal to or greater than 95%.

In the medical conduit, the light is easily released from the section where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or greater than 95% to the human tissue. Thus, the sterilization effect against the bacteria interposed between the human tissue and the conduit portion surrounded by the human tissue can be much more enhanced.

Further, the medical conduit preferably includes a first zone including the section surrounded by the human tissue, and a second zone on the opposite side of the first zone from the outside of the human body. The first zone is preferably configured such that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or greater than 95%. The second zone is preferably configured such that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is less than 95%.

In this case, the light transmitted through the first zone is attenuated in the second zone, and therefore, as compared to a case where the entirety of the medical conduit is formed by the first zone, emission of the light from, e.g., the end portion of the medical conduit can be reduced. Thus, unintended irradiation of the human tissue with the light in the wavelength band of 270 nm to 340 nm can be reduced, and influence of the light on the human tissue can be reduced.

In addition, the first zone preferably includes at least part of the section arranged outside the human body.

Since the first zone includes the section arranged outside the human body, the amount of attenuation of the light, which is introduced from the outside of the human body and propagates to the section surrounded by the human tissue, in the wavelength band of 270 nm to 340 nm can be reduced. Thus, the sterilization effect against the bacteria interposed between the human tissue and the conduit portion surrounded by the human tissue can be much more enhanced without the need for excessively increasing the intensity of light having the wavelength band of 270 nm to 340 nm and needing to propagate in the medical conduit.

Moreover, a recessed-raised portion is preferably provided at part of a surface of the section of the medical conduit surrounded by the human tissue.

In this case, as compared to the case of providing no recessed-raised portion, the amount of light emitted from the portion provided with the recessed-raised portion can be increased. Thus, the amount of light released from the medical conduit to the human tissue can be adjusted by the recessed-raised portion.

Further, a height difference at the recessed-raised portion preferably increases with a distance from the opening end of the medical conduit on the outside of the human body.

In this case, a decrease in the amount of light emitted from the portion provided with the recessed-raised portion with a distance from the human body outer side of the medical conduit is suppressed. Non-uniformity in the intensity of light emitted from the portion provided with the recessed-raised portion of the medical conduit along the longitudinal direction of the medical conduit can be reduced.

In addition, at part of the surface of the section of the medical conduit surrounded by the human tissue, multiple reflectors dispersed on the surface are preferably provided.

In this case, a predetermined amount of light released from the section surrounded by the human tissue to the human tissue can be ensured while the light can easily propagate to a lumen side of the human body.

Moreover, the percentage of the reflectors per unit area of the medical conduit preferably decreases with a distance from the opening end of the medical conduit on the outside of the human body.

In this case, a decrease in the amount of light emitted from the portion provided with the reflectors with a distance from the human body outer side of the medical conduit is suppressed. Thus, non-uniformity in the intensity of light emitted from the portion provided with the reflectors of the medical conduit along the longitudinal direction of the medical conduit can be reduced.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments for carrying out the present invention and variations thereof will be described by way of example with reference to the attached drawings. The embodiments and the variations described below by way of example are for the sake of easy understanding of the present invention, and are not intended to interpret the present invention in a limited manner. Changes and modifications can be made to the present invention without departing from the gist thereof.

(1) First Embodiment

FIG. 1is a view of an outline configuration of a sterilization system in a first embodiment. As illustrated inFIG. 1, a sterilization system1of the present embodiment includes, as main components, a peritoneal dialysis catheter2and a light introduction device3.

The catheter2is a medical conduit used as a flow path through which a dialysate solution is taken in or out of a peritoneal cavity, and is in such a tubular shape that a thick portion surrounds an inner cavity. In the present embodiment, the catheter2has an intracorporeal arrangement portion21as a section arranged in a human abdominal area from the outside to the inside of a human body and arranged in the peritoneal cavity as the inside of the human body, an extracorporeal arrangement portion22as a section arranged outside the human body, and a human tissue arrangement portion23as a section surrounded by a human tissue10. Note that a portion of the human tissue10where the human tissue arrangement portion23is placed is sometimes called a “subcutaneous tunnel.”

The light introduction device3is provided at a middle section of the extracorporeal arrangement portion22. An opening end2A of the extracorporeal arrangement portion22is covered with a connector2CN, and communicates with an opening end of an external tube4on one end side through an external connector4CN connected to the connector2CN. Note that in a state in which the connector2CN of the catheter2and the external connector4CN of the external tube4are connected to each other, the dialysate solution can be taken in or out of the peritoneal cavity through the catheter2and the external tube4.

Cuffs24are provided at the human tissue arrangement portion23. The cuff24is a fibrous member provided on a surface of the human tissue arrangement portion23, and is fixed to the human tissue10by adhesion to the human tissue10to reduce unintended detachment of the catheter2. The cuffs24of the present embodiment include an external cuff24A and an internal cuff24B. The external cuff24A is positioned closer to the opening end2A of the catheter2on a human body outer side, and the internal cuff24B is positioned closer to an opening end2B of the catheter2on a human body inner side. Note that the number of cuffs24may be one or three or more, and the cuffs24may be omitted.

FIG. 2is a view of the outline of the peritoneal dialysis catheter2not placed in the human body. As illustrated inFIG. 2, the catheter2of the present embodiment includes a first zone SC1where a light transmission for a wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95%, and a second zone SC2where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is lower than 95%. Note that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length means the percentage of light, having the wavelength band of 270 nm to 340 nm, passing through a portion from a certain spot of the catheter2to a point apart from the certain spot by 1 mm in a longitudinal direction of the catheter2. Moreover, light included in the wavelength band of 270 nm to 340 nm will be hereinafter referred to as “ultraviolet light.”

In the case of the present embodiment, the extracorporeal arrangement portion22and the human tissue arrangement portion23of the catheter2are taken as the first zone SC1, and the intracorporeal arrangement portion21of the catheter2is taken as the second zone SC2. That is, a zone from the opening end2A of the catheter2on the human body outer side to a boundary position between the human tissue arrangement portion23and the intracorporeal arrangement portion21is taken as the first zone SC1, and a zone from such a boundary position to the opening end2B of the catheter2on the human body inner side is taken as the second zone SC2. Thus, in a case where the catheter2is placed in the human body as illustrated inFIG. 1, the second zone SC2is positioned on the opposite side of the first zone SC1from the human body outer side. The catheter2is made of a material allowing transmission of the ultraviolet light, and such a material of the catheter2includes, for example, silicone resin. The ultraviolet transmission of the silicone resin varies depending on the type of such resin, and the transmission varies according to a material composition, a molecular structural skeleton, an additive agent, and the type and amount of filler. Thus, the material is selected as necessary so that the transmissions of the first zone SC1and the second zone SC2can be differentiated from each other. Moreover, in the case of obtaining a high transmission in an ultraviolet range, it is effective to decrease an additive agent having an ultraviolet absorption ability or not to use such an agent.

The length of the catheter2is such a length that the opening end2B of the catheter2on the human body inner side is arranged in a recessed portion5(FIG. 1) of the peritoneal cavity. Note that the recessed portion5of the peritonea is sometimes called a “Douglas' pouch” as a dent of the peritonea. In the case of a male, the recessed portion5is positioned between the bladder and the rectum. In the case of a female, the recessed portion5is positioned between the uterus and the rectum. The inner diameter of the catheter2is within a range of equal to or greater than 2.0 mm and equal to or less than 4.0 mm, and the thickness of the catheter2is within a range of equal to or greater than 0.5 mm and equal to or less than 1.5 mm. Note that the thickness of the catheter2is a difference between the outer diameter and the inner diameter of the catheter2.

The light introduction device3is a device configured to introduce the ultraviolet light from the extracorporeal arrangement portion22of the catheter2, and in the present embodiment, is detachable from the extracorporeal arrangement portion22of the catheter2.

FIG. 3is a view of the outline of the light introduction device in a closed state,FIG. 4is a view of the outline of the light introduction device in an open state, andFIG. 5is a sectional view of the state of attachment of the light introduction device to the catheter along an X-X section ofFIG. 3. As illustrated inFIGS. 3 to 5, the light introduction device3of the present embodiment includes, as main components, a housing30, a light emitter40, and a light guide member50.

The housing30is a tubular member surrounding the extracorporeal arrangement portion22of the catheter2. The housing30may be made of a substantially ultraviolet-impermeable material.

In the case of the present embodiment, the housing30includes a first tube portion PT1, a second tube portion PT2, and a third tube portion PT3. The first tube portion PT1is a frusto-conical member whose outer and inner diameters are narrowed with a distance from the second tube portion PT2, and the light guide member50is attached to the inside of such a tube.

The second tube portion PT2is a circular tube-shaped member having an inner diameter substantially equal to the outer diameter of the catheter2, and can fix part of the extracorporeal arrangement portion22of the catheter2.

The third tube portion PT3is a circular tube-shaped member having an inner diameter greater than that of the second tube portion PT2, and the light guide member50attached to the first tube portion PT1and an end surface of the second tube portion PT2face each other through a space AR inside such a tube.

The housing30of the present embodiment as described above is openable by a first half body31, a second half body32having the substantially same shape as that of the first half body31, and a hinge33configured to open/close the first half body31and the second half body32. The first half body31and the second half body32are closed through the hinge33such that an inner wall surface of the first half body31and an inner wall surface of the second half body32face each other, and such a closed state is maintained by a not-shown stopper.

A groove portion34is provided at the inner wall surface of the first half body31at the second tube portion PT2, and a groove portion35is provided at the inner wall surface of the second half body32at the second tube portion PT2. In a case where the first half body31and the second half body32are brought into the closed state in such a manner that the pair of groove portions34,35enters part of the extracorporeal arrangement portion22, the extracorporeal arrangement portion22is fixed by the second tube portion PT2, and the light introduction device3is fixed to the catheter2. That is, in the present embodiment, the light introduction device is detachably fixed to the catheter2by sandwiching of the catheter2.

The light emitter40is configured to emit light having a peak wavelength in the wavelength band of 270 nm to 340 nm, and includes LEDs42, electric wires43, and a power source44. The LEDs42are, in the housing30, arranged on the end surface of the second tube portion PT2facing the light guide member50attached to the first tube portion PT1, and the power source44is arranged outside the housing30. The electric wires43connect, through a wall of the second tube portion PT2, the LEDs42arranged inside the housing30and the power source44arranged outside the housing30, for example. The light emitter40turns on the LEDs42based on power supplied from the power source44through the electric wires43, and emits the ultraviolet light to the light guide member50.

In the case of the present embodiment, the LEDs42have, as illustrated inFIG. 4, a first LED42A arranged on the end surface of the second tube portion PT2at the first half body31, and a second LED42B arranged on the end surface of the second tube portion PT2at the second half body32. InFIG. 4, the first LED42A is arranged on a far side with respect to the groove portion34in a direction perpendicular to the plane of paper, and therefore, is indicated by a dashed line. The second LED42B is also arranged on the far side with respect to the groove portion35in the direction perpendicular to the plane of paper, and therefore, is indicated by a dashed line. Note that the LEDs42are two LEDs including the first LED42A and the second LED42B in the present embodiment, but may include a single LED or three or more LEDs. Moreover, the LEDs42are preferably arranged such that an incident surface of the light guide member50is uniformly irradiated with light.

The light guide member50is a tubular member surrounding a side surface of part of the extracorporeal arrangement portion22of the catheter2. The material of the light guide member50includes, for example, quartz.

In the case of the present embodiment, the light guide member50includes, as illustrated inFIG. 4, a first light guide half body51fixed to an inner wall of the first half body31, and a second light guide half body52fixed to an inner wall of the second half body32. A groove portion51A is provided on the opposite surface side of the surface side contacting the inner wall of the first half body31at the first light guide half body51, and a groove portion52A is provided on the opposite surface side of the surface side contacting the inner wall of the second half body32at the second light guide half body52.

In a case where the first half body31and the second half body32are brought into the closed state in such a manner that part of the extracorporeal arrangement portion22of the catheter2is sandwiched by the pair of groove portions51A,52A, the first light guide half body51fixed to the first half body31and the second light guide half body52fixed to the second half body32form the light guide member50as illustrated inFIG. 5. In this case, the side surface of part of the extracorporeal arrangement portion22of the catheter2is surrounded by the light guide member50, and the light guide member50and the catheter2closely contact each other.

Of the light guide member50surrounding part of the extracorporeal arrangement portion22of the catheter2as described above, an entrance-side end portion50A facing an opening end2A side of the extracorporeal arrangement portion22of the catheter2contacts light emission surfaces of the first LED42A and the second LED42B, and light emitted from the first LED42A and the second LED42B enters the entrance-side end portion50A. Of the light guide member50, an emitting-side end portion50B facing an opening end2B side of the catheter2on the human body inner side is, on the other hand, diagonally inclined toward the catheter2as extending toward the opening end2B of the catheter2on the human body inner side. That is, when the opening end2B of the catheter2on the human body inner side is one opening end, the opening end2A of the extracorporeal arrangement portion22is the other opening end, the emitting-side end portion50B of the light guide member50is one end portion, and the entrance-side end portion50A is the other end portion, one end portion of the light guide member50facing one opening end side of the catheter2is diagonally inclined toward the catheter2as extending toward one opening end side of the catheter2, and light is entered from the other end side of the light guide member50facing the other opening end side of the catheter2.

<Sterilization Method by Sterilization System>

Next, a sterilization method by the sterilization system1of the present embodiment will be described with reference toFIG. 6.FIG. 6is a sectional view of a light propagation state. Note that inFIG. 6, hatching of the section of the catheter2is omitted for the sake of easy understanding of the light propagation state.

In the case of sterilizing, e.g., the catheter2placed in the human body, part of the extracorporeal arrangement portion22of the catheter2is sandwiched by the groove portions34,35of the second tube portion PT2, the groove portion51A of the first light guide half body51, and the groove portion52A of the second light guide half body52. Thereafter, the first half body31and the second half body32are closed, and in such a closed state, the first LED42A and the second LED42B are turned on.

As illustrated inFIG. 6, in the case of turning on the first LED42A and the second LED42B, the ultraviolet light is emitted from the first LED42A and the second LED42B. Such ultraviolet light enters the light guide member50through the entrance-side end portion50A of the light guide member50facing the LEDs42, and propagates toward the emitting-side end portion50B of the light guide member50.

As described above, the emitting-side end portion50B of the light guide member50is diagonally inclined toward the catheter2as extending toward the opening end2B of the catheter2on the human body inner side. Thus, large part of light propagating from the entrance-side end portion50A of the light guide member50to the emitting-side end portion50B is reflected on the emitting-side end portion50B. The light reflected on the emitting-side end portion50B propagates toward the catheter2in a state diagonally to the longitudinal direction of the catheter2, and enters the thick portion of the catheter2. Note that a reflector configured to reflect incident light from the entrance-side end portion50A toward the catheter2may be provided on the surface of the emitting-side end portion50B. A metal thin film made of aluminum or silver can be utilized as the reflector.

As described above, in the present embodiment, the transmission for the ultraviolet light per millimeter in length at the extracorporeal arrangement portion22and the human tissue arrangement portion23of the catheter2is equal to or higher than 95%. Thus, large part of light having entered the thick portion of the catheter2can propagate, using the catheter2as a waveguide, toward the opening end2B of the catheter2on the human body inner side in the thick portion with substantially no attenuation.

The catheter2contacts atmospheric air at the extracorporeal arrangement portion22, and therefore, light propagating in the thick portion of the extracorporeal arrangement portion22propagates with leakage to the outside of the catheter2being reduced in a total reflection mode. Moreover, the human tissue arrangement portion23of the catheter2is surrounded in contact with the human tissue, and a refractive index difference between the human tissue arrangement portion23and the human tissue10is smaller than a refractive index difference between the extracorporeal arrangement portion22and the atmospheric air. Thus, part of light reaching the human tissue arrangement portion23is released from the human tissue arrangement portion23to the human tissue10. Thus, in a case where bacteria is interposed between the human tissue arrangement portion23of the catheter2and the human tissue10, the bacteria might be directly irradiated with the ultraviolet light. Note that for light propagation in the thick portion of the catheter2as described above, light is preferably emitted from the LEDs42before the inner cavity of the catheter2is filled with the dialysate solution. Note that light may be emitted from the LEDs42in a state in which the inner cavity of the catheter2is filled with the dialysate solution.

In a case where a light (a light of about 1 mW/cm2) of about 1 mW per square area of 1 cm in length and 1 cm in width is released from the human tissue arrangement portion23, if the peak wavelength emitted from the LED42is 265 nm, the rate of sterilization by light is 99% in an irradiation time of about four seconds. Moreover, if the peak wavelength emitted from the LED42is 320 nm, the rate of sterilization by light is 99% in an irradiation time of about 50 minutes.

Note that as described above, the transmission for the ultraviolet light per millimeter in length at the intracorporeal arrangement portion21of the catheter2is lower than 95%, and the length of the intracorporeal arrangement portion21is greater than the length of the extracorporeal arrangement portion22. Thus, large part of light propagating in the intracorporeal arrangement portion21through the human tissue arrangement portion23of the catheter2is attenuated, and leakage of light from the opening end2B of the catheter2on the human body inner side is reduced.

As described above, the light introduction device3of the present embodiment introduces light through part of an outer surface of a section of the catheter2arranged outside the human body, the catheter2being the medical conduit having the inner cavity for passage of at least one of a substance introduced into the human body or a substance discharged from the human body and having the light-permeable thick portion. Moreover, the sterilization system1using the light introduction device3includes the catheter2and the light introduction device3.

According to the sterilization system1and the light introduction device3as described above, light is introduced into the light-permeable medical conduit so that the light can propagate to even bacteria present in a substance contacting the catheter2through the catheter2as the medical conduit. Thus, the bacteria present in the substance contacting the catheter2can be deactivated by the light. In this manner, according to the sterilization system1and the light introduction device3of the present invention, a sterilization effect against the substance contacting the medical conduit can be enhanced.

Moreover, the light introduction device3of the present embodiment includes the light guide member50surrounding the side surface of the extracorporeal arrangement portion22, and the light guide member50is detachable from the catheter2. Moreover, the emitting-side end portion50B facing the human body inner side of the catheter2is diagonally inclined toward the catheter2as extending toward the human body inner side of the catheter2, and causes light entered from an entrance-side end portion50A side facing the human body outer side of the catheter2to enter diagonally to the longitudinal direction of the catheter2.

Thus, even in a state in which the catheter2is already arranged in the human body, more light can be introduced into the catheter2. Moreover, even if the light introduction device3is unexpectedly damaged, the light introduction device3can be replaced with the catheter2remaining in the human body.

Moreover, in the light introduction device3of the present embodiment, the light guide member50and the catheter2closely contact each other. Thus, as compared to a case where a clearance is formed between the light guide member50and the catheter2, the amount of light introduced into the catheter2from the LEDs42through the light guide member50can be increased.

Further, the light introduction device3of the present embodiment causes the light having the peak wavelength in the wavelength band of 270 nm to 340 nm to be entered to the catheter2.

Thus, the bacteria interposed between the catheter2and the human tissue10can be, without passage through the human tissue10, directly irradiated with light having a wavelength with a high sterilization ability against the bacteria through the catheter2.

In addition, in the sterilization system1of the present embodiment, the human tissue arrangement portion23of the catheter2is configured such that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95%.

Thus, in the catheter2, light is easily released toward the human tissue10from the section where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95%. Thus, the sterilization effect against the bacteria interposed between the human tissue10and a conduit portion surrounded by the human tissue10can be further enhanced.

Moreover, the catheter2of the present embodiment includes the first zone SC1and the second zone SC2on the opposite side of the first zone SC1from the human body outer side. The first zone SC1is configured such that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95%, and the second zone SC2is configured such that the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is lower than 95%.

Thus, as compared to a case where the entirety of the catheter2is formed by the first zone SC1, unintended irradiation of the human tissue10with the light in the wavelength band of 270 nm to 340 nm from the catheter2can be reduced, and influence of light on the human tissue10can be reduced.

Moreover, the first zone SC1of the catheter2of the present embodiment includes the intracorporeal arrangement portion21. Thus, the amount of attenuation of the light in the wavelength band of 270 nm to 340 nm can be reduced, the light being introduced from the outside of the human body and propagating to the human tissue arrangement portion23. Thus, the sterilization effect against the bacteria interposed between the human tissue10and the human tissue arrangement portion23can be further enhanced without the need for excessively increasing the intensity of the light having the wavelength band of 270 nm to 340 nm and needing to propagate in the catheter2.

(2) Second Embodiment

Next, a second embodiment will be described. Note that the same reference numerals are used to represent configurations similar to those described in the first embodiment, and unless otherwise described, overlapping description will be described.

FIG. 7is a view of a configuration of a light introduction device provided at a sterilization system in the second embodiment from the same view point as that ofFIG. 5. As illustrated inFIG. 7, in the sterilization system of the present embodiment, a third tube portion PT3of a housing30is omitted, and a first tube portion PT1and a second tube portion PT2form the housing30. Moreover, the sterilization system of the present embodiment is different from that of the above-described first embodiment in that a light emitter140having a different configuration from that of the light emitter40is employed instead of the light emitter40of the first embodiment.

The light emitter140includes two optical fibers143A,143B and a light source144. One end portion of each of the optical fibers143A,143B is optically connected to the light source144. Moreover, the other end portion of each of the optical fibers143A,143B is inserted into a through-hole provided along a longitudinal direction of the second tube portion PT2, and is fixed to the second tube portion PT2. An end surface on an end side of each of the optical fibers143A,143B fixed to the second tube portion PT2contacts an entrance-side end portion50A of a light guide member50.

Note that two optical fibers143A,143B are employed in the present embodiment, but may be one or three or more. Moreover, the end surfaces of the optical fibers143A,143B on the side fixed to the second tube portion PT2may be apart from an end surface of the entrance-side end portion50A of the light guide member50.

The light emitter140as described above irradiates the entrance-side end portion50A of the light guide member50with ultraviolet light generated by the light source144through the optical fibers143A,143B.

Light entering the entrance-side end portion50A of the light guide member50from the light emitter140is, as in the case of the above-described first embodiment, reflected on an emitting-side end portion50B of the light guide member50, and enters a thick portion of a catheter2. The light having entered the thick portion of the catheter2propagates, as in the case of the above-described first embodiment, in the catheter2as a waveguide, and is released from a human tissue arrangement portion23of the catheter2toward a human tissue10.

Thus, as in the above-described first embodiment, the sterilization system of the present embodiment can directly irradiate, without passage through the human tissue10, bacteria interposed between the catheter2and the human tissue10with the ultraviolet light. Thus, as compared to a case where ultraviolet light is irradiated from the outside of a human body, bacteria interposed between the human tissue10and a conduit portion surrounded by the human tissue10can be sterilized such that the amount of such bacteria is decreased.

Next, a third embodiment will be described. Note that the same reference numerals are used to represent configurations similar to those described in the first embodiment, and unless otherwise described, overlapping description will be omitted.

FIG. 8is a view of an outline configuration of a sterilization system in the third embodiment. As illustrated inFIG. 8, the sterilization system1of the present embodiment is different from that of the above-described first embodiment in that a control device60configured to control a light introduction device3is newly provided.

The control device60has a housing61integrally molded with a housing30in the light introduction device3, and a gripping portion62molded integrally with the housing61. Note that the housing61may be formed integrally with a first half body31of the housing30or a second half body32of the housing30.

At a surface of the housing61, a power button63configured to switch ON/OFF of power and a time display64configured to display time after LEDs42A,42B has started lighting are provided. Moreover, at the surface of the housing61, a connection switch button65configured to switch connection with the power source44between the first LED42A and the second LED42B and a wavelength display66configured to display a current peak wavelength are provided. Further, the power source44and electric wires43of a light emitter40are provided inside the housing61. Note that in the present embodiment, the peak wavelength of light emitted from the first LED42A and the peak wavelength of light emitted from the second LED42B are different from each other.

In a case where the power button63is switched from OFF to ON, the control device60takes such a switch point as a trigger to supply power from the power source44to, e.g., the first LED42A until the power button63is switched from ON to OFF, thereby continuing ON of the first LED42A. In addition, the control device60measures time after the point of switching the power button63from OFF to ON, and displays, as irradiation time, a measurement result on the time display64until the power button63is switched from ON to OFF.

Thus, the sterilization system1of the present embodiment can intuitively provide the irradiation time to a user, and can irradiate bacteria interposed between a catheter2and a human tissue10with ultraviolet light for such proper irradiation time that influence on the human tissue10does not reach equal to or greater than a certain degree.

Moreover, in a case where the connection switch button65is switched from the first LED42A to the second LED42B, the control device60takes such a switch point as a trigger to disconnect the power source44and the first LED42A from each other and connect the power source44and the second LED42B to each other. At this point, on the wavelength display66, the control device60displays, as the current peak wavelength, the peak wavelength of the second LED42B instead of the peak wavelength of the first LED42A displayed on the wavelength display66. On the other hand, in a case where the connection switch button65is switched from the second LED42B to the first LED42A, the control device60takes such a switch point as a trigger to disconnect the power source44and the second LED42B from each other and connect the power source44and the first LED42A to each other. At this point, on the wavelength display66, the control device60displays, as the current peak wavelength, the peak wavelength of the first LED42A instead of the peak wavelength of the second LED42B displayed on the wavelength display66.

As the wavelength of light released from the catheter to the human tissue10becomes closer to 270 nm, a sterilization capability against the bacteria interposed between the catheter2and the human tissue10is improved. Meanwhile, the influence on the human tissue10increases. On the other hand, as the wavelength of light released from the catheter2to the human tissue10becomes closer to 340 nm, the sterilization capability against the bacteria interposed between the catheter2and the human tissue10is reduced. Meanwhile, the influence on the human tissue decreases. Thus, the sterilization system1of the present embodiment can more improve the sterilization capability according to, e.g., ultraviolet absorption characteristics of the human tissue10surrounding the catheter2and the irradiation time of light for irradiation of the human tissue10while performing adjustment such that the influence on the human tissue10decreases. Note that the first LED42A and the second LED42B having different peak wavelengths are switched, but an LED whose peak wavelength is switchable may be used.

Next, a fourth embodiment will be described. Note that the same reference numerals are used to represent configurations similar to those described in the first embodiment, and unless otherwise described, overlapping description will be omitted.

FIG. 9is a view of an outline configuration of a light introduction device provided at a sterilization system in the fourth embodiment. As illustrated inFIG. 9, a light introduction device100of the present embodiment is a device configured to introduce ultraviolet light from an extracorporeal arrangement portion22of a catheter2, and includes multiple optical fibers101and a fixing member102as main components.

The multiple optical fibers101are members in which light propagates, and each optical fiber101has a core and a clad covering the core. A difference between the refractive index of the core of each optical fiber101and the refractive index of the catheter2is about 3%. Such a refractive index difference is preferably equal to or lower than 3%. Moreover, one end portion of each optical fiber101has an inclined surface101A inclined with respect to the center axis AX of the optical fiber. An angle θ1between a line LN perpendicular to the inclined surface101A and the center axis AX of the optical fiber is equal to or greater than 46 degrees. Note that the center axis AX of the optical fiber can be also understood as the optical axis of the optical fiber. The angle θ1corresponds to the entrance angle of light propagating in the core of the optical fiber and entering an interface with the inclined surface101A from the inclined surface101A.

The fixing member102is a member configured to fix the multiple optical fibers101, and has flexibility. The fixing member102has an arrangement surface102A arranged on an outer surface of the catheter2, and covers end portions of the multiple optical fibers101from an arrangement surface102A side such that each of the inclined surfaces101A of the multiple optical fibers101are exposed.

In the case of the present embodiment, the inclined surface101A of each of the multiple optical fibers101is positioned on the substantially same plane as that of the arrangement surface102A of the fixing member102. Note that as long as the inclined surface101A of each of the multiple optical fibers101is substantially parallel to the arrangement surface102A of the fixing member102, the inclined surface101A is not necessarily positioned on the arrangement surface102A of the fixing member102. Note that in a state in which the arrangement surface102A contacts the outer surface of the catheter2, the inclined surface101A of the optical fiber101is preferably positioned on the arrangement surface102A of the fixing member102not to reflect light emitted from the inclined surface101A on the outer surface of the catheter2.

Moreover, in the case of the present embodiment, the inclined surfaces101A of the multiple optical fibers101are arranged at intervals ITL in a predetermined direction. Note that as long as the inclined surfaces101A of the multiple optical fibers101are arranged at the intervals ITL in the predetermined direction, a position relationship among the optical fibers101may be shifted to a certain degree. Moreover, various arrangement forms may be employed as arrangement of the inclined surface101A of each of the multiple optical fibers101. For example, the inclined surfaces101A of the multiple optical fibers101may be arranged in two lines parallel to each other, or may be arranged in a grid pattern. Note that the inclined surfaces101A are preferably arranged at the intervals ITL in the predetermined direction so that the inclined surface101A of each of the multiple optical fibers101can be arranged along a circumferential direction of the outer surface of the catheter2.

Note that end portions of the multiple optical fibers101on the opposite side of an inclined surface101A side are connected to a not-shown light source unit, and the ultraviolet light is introduced from the light source unit to the core of each optical fiber101. For example, in a case where the diameter of the core of the optical fiber101is 1 mm, an output of about 50 mW per optical fiber101can be obtained.

The above-described light introduction device100can be, for example, manufactured as follows.FIG. 10A-FIG. 10Cillustrate views of the state of manufacturing of the light introduction device.

First, as illustrated inFIG. 10A, e.g., a box200having a rectangular parallelepiped space is prepared, and the multiple optical fibers101are, on one end side thereof, diagonally arranged at the intervals ITL in the box200. An angle θ2between a line LN1perpendicular to a bottom surface of the box200and the center axis AX of the optical fiber corresponds to the angle θ1between the line LN perpendicular to the inclined surface101A and the center axis AX of the optical fiber as described above, and therefore, is equal to or greater than 46 degrees. Note that the angle θ2can be adjusted by a change in a box height, for example.

Next, fixing resin such as silicone resin or urethane resin is injected into the box in an uncured state, and as illustrated inFIG. 10B, the multiple optical fibers101fixed by the fixing resin102X in a cured state are taken out of the box200. Next, as indicated by a chain double-dashed line ofFIG. 10C, the fixing resin102X and the multiple optical fibers101are cut parallel to a bottom surface of the fixing resin102X from a predetermined height position of the fixing resin102X. Thereafter, a cut surface is polished, and accordingly, the light introduction device100as illustrated inFIG. 9is obtained.

<Sterilization Method by Sterilization System>

Next, a sterilization method by the sterilization system of the present embodiment will be described with reference toFIGS. 11 and 12.FIG. 11is a view of the sterilization system attached to the light introduction device100.FIG. 12is a sectional view of a light propagation state in the sterilization system of the present embodiment. Note that inFIG. 12, hatching of the sections of the catheter2and the optical fibers101is omitted for the sake of easy understanding of the light propagation state.

As illustrated inFIG. 11, in the sterilization system1of the present embodiment, the fixing member102is wound around the outer surface of the catheter2, and in this manner, the light introduction device100is attached to the catheter2. The fixing member102has the flexibility as described above, and therefore, even in a state in which the catheter2is placed in a human body, the light introduction device100can be attached onto the outer surface of the catheter2. Note that the fixing member102wound around the outer surface of the catheter2may be fixed with a predetermined fixing tool. Note that in the present embodiment, the light introduction device has the light source unit120configured to introduce the ultraviolet light to the cores of the optical fibers101, and the light source unit120is connected to each optical fiber101.

In a state in which the light introduction device100is provided at a section of the catheter2arranged outside the human body as described above, each optical fiber101is arranged closer to the catheter2toward an opening end of the catheter2on a human body inner side. That is, in a case where the opening end of the catheter2on the human body inner side is one opening end, each optical fiber101is arranged closer to the catheter2as a medical conduit toward one opening end side.

As illustrated inFIG. 12, in a state in which the light introduction device100is attached, the inclined surface101A of each of the multiple optical fibers101positioned on the substantially same plane as that of the arrangement surface102A of the fixing member102contacts the outer surface of the catheter2. Thus, in the present embodiment, the outer surface of the catheter2as the medical conduit and the inclined surfaces101A of the optical fibers101face each other in parallel. Moreover, the direction of arrangement of the inclined surfaces101A of the multiple optical fibers101is substantially coincident with the circumferential direction of the outer surface of the catheter2.

In this state, the ultraviolet light is introduced into the core101cof each of the multiple optical fibers101fixed to the fixing member102from the light source unit120. The ultraviolet light propagates in the core101cof each optical fiber101, and enters the outer surface of the catheter2contacting the inclined surface101A of such an optical fiber101.

When the entrance angle of light entering the outer surface of the catheter2is equal to or greater than 46 degrees, light introduced into a thick portion of the catheter2is easily totally reflected on an inner surface of the catheter2. In the present embodiment, the angle between the line LN perpendicular to the inclined surface101A of the optical fiber101and the center axis AX of the optical fiber is equal to or greater than 46 degrees. Thus, the entrance angle of the ultraviolet light propagating in the core101cof each optical fiber101is equal to or greater than 46 degrees. Thus, large part of the ultraviolet light introduced into the thick portion of the catheter2is totally reflected on the inner surface of the catheter2, and propagates in the thick portion of the catheter2toward the opening end2B on the human body inner side. As described in the first embodiment, the ultraviolet light propagating in the thick portion of the catheter2is released from a human tissue arrangement portion23of the catheter2to a human tissue10.

As described above, according to the sterilization system of the present embodiment, bacteria interposed between the catheter2and the human tissue10can be directly irradiated with the ultraviolet light from the inside as in the above-described first embodiment. Thus, as compared to the case of irradiating a human body with ultraviolet light from the outside, bacteria interposed between the human tissue10and a conduit portion surrounded by the human tissue10can be efficiently sterilized.

Note that the multiple optical fibers101of the light introduction device100in the present embodiment are fixed to the fixing member102having the flexibility, and the inclined surfaces101A of the optical fibers101are arranged at the intervals ITL in the predetermined direction. Thus, the direction of arrangement of the optical fibers101becomes coincident with the circumferential direction of the outer surface of the catheter2as described above so that the ultraviolet light can be introduced into the thick portion of the catheter2from the circumferential direction. Thus, the ultraviolet light can be released toward the human tissue10from a circumferential direction of the human tissue arrangement portion23of the catheter2, and as a result, an ultraviolet irradiation area can be more expanded.

Moreover, the multiple optical fibers101in the present embodiment are fixed to the fixing member102having the flexibility, and the inclined surfaces101A of the optical fibers101are positioned on the same plane as that of the arrangement surface102A of the fixing member102. Thus, the fixing member102having a predetermined length is wound around the catheter2, and both end surfaces of the fixing member102are bonded to each other. In this manner, the end portions of the optical fibers101can substantially closely contact the outer surface of the catheter2. Thus, as described above, reflection of light emitted from the inclined surfaces101A on the outer surface of the catheter2is substantially eliminated, and therefore, such light can be efficiently introduced into the catheter2.

Note that at least one of the outer diameter, the fiber number, or the interval ITL of the optical fiber101arranged in the predetermined direction is easily differentiated in manufacturing. Thus, even in the case of using the catheters2with different outer diameters on site, the detachable light introduction device100can be prepared according to use.

Next, a fifth embodiment will be described. Note that the same reference numerals are used to represent configurations similar to those described in the first embodiment, and unless otherwise described, overlapping description will be omitted.

FIG. 13is a view of an outline configuration of a dialysis device including a sterilization system in the fifth embodiment. That is, the sterilization system1of the present embodiment is part of the dialysis device300. As illustrated inFIG. 13, the dialysis device300includes, as main components, a patient monitoring device310, a blood circuit320, a dialyzer330, a dialysate solution flow path340, and a dialysate solution refilling flow path350.

The blood circuit320is a path allowing passage of blood taken out from a not-shown shunt embedded in a human body, and includes a tube having elasticity. In the present embodiment, the tube forming the blood circuit320has a configuration similar to that of the catheter2as the medical conduit of the first embodiment. The dialyzer330is provided at a middle section of the blood circuit320. Of the blood circuit320, an artery-side blood circuit320A on an inlet port side of the shunt with respect to the dialyzer330is provided with a blood pump321. Note that each of the artery-side blood circuit320A of the blood circuit320and a vein-side blood circuit320B on an outlet port side of the shunt with respect to the dialyzer330may be provided with an air trap chamber configured to remove air from the blood and trap a clot.

The blood pump321is a roller pump configured to send, with, e.g., a not-shown rotary roller, the blood to the blood circuit320by means of the blood circuit320, and causes the blood to flow into the blood circuit320.

The dialyzer330is a dialyzing machine configured to remove a waste from the blood, and has a body case331with a housing space for housing a dialysate solution and multiple semipermeable membrane tubes332arranged in the housing space.

At an input portion of the body case331, one end of the artery-side blood circuit320A and one end of each semipermeable membrane tube332in the body case331are connected to each other. At an output portion of the body case331, one end of the vein-side blood circuit320B and the other end of each semipermeable membrane tube332in the body case331are connected to each other.

The patient monitoring device310is coupled to other sections of the body case331than the input portion and the output portion through the dialysate solution flow path340. The dialysate solution flow path340is a path allowing passage of the dialysate solution, and includes a tube having elasticity. In the present embodiment, the tube forming the dialysate solution flow path340has a configuration similar to that of the catheter2as the medical conduit of the first embodiment.

The patient monitoring device310is configured to supply and recover the dialysate solution through the dialysate solution flow path340. Thus, the dialysate solution supplied from the patient monitoring device310flows into the housing space of the body case331through an upstream-side dialysate solution flow path340A. On the other hand, the blood of a dialysis patient flows into an inner cavity of each semipermeable membrane tube332arranged in the housing space of the body case331through the artery-side blood circuit320A.

Moreover, in the present embodiment, the artery-side blood circuit320A and the upstream-side dialysate solution flow path340A are connected to each other through the dialysate solution refilling flow path350. Specifically, one end of the dialysate solution refilling flow path350is connected to a portion of the artery-side blood circuit320A between the blood pump321and the dialyzer330, and the other end of the dialysate solution refilling flow path350is connected to the upstream-side dialysate solution flow path340A. The dialysate solution refilling flow path350is a path allowing passage of the dialysate solution branched from the dialysate solution flow path340A, and includes a tube having elasticity. In the present embodiment, the tube forming the dialysate solution refilling flow path350has a configuration similar to that of the medical conduit of the first embodiment. A dialysate solution refilling pump351is provided in the middle of the dialysate solution refilling flow path350. The dialysate solution refilling pump351is a roller pump configured to send, with, e.g., a not-shown rotary roller, the dialysate solution branched from the dialysate solution flow path340A to the artery-side blood circuit320A by means of the dialysate solution refilling flow path350.

The dialysate solution refilling flow path350is provided with a light introduction device3. The light introduction device3has a configuration similar to that of the light introduction device3in the first embodiment. Thus, as in the light introduction device3fixed to the catheter2in the first embodiment, the light introduction device3of the present embodiment is fixed to the medical conduit forming the dialysate solution refilling flow path350. Thus, in the present embodiment, the dialysate solution refilling flow path350and the light introduction device3form the sterilization system1. Note that in the present embodiment, an emitting-side end portion50B of a light guide member50at the light introduction device3faces an opening end of the dialysate solution refilling flow path350on an artery-side blood circuit320A side. Thus, in a case where the opening end of the dialysate solution refilling flow path350on the artery-side blood circuit320A side is one opening end, an opening end of the dialysate solution refilling flow path350closer to the dialysate solution flow path340A is the other opening end, the emitting-side end portion50B of the light guide member50is one end portion, and an entrance-side end portion50A is the other end portion, one end portion of the light guide member50facing one opening end side of the dialysate solution refilling flow path350is diagonally inclined toward the dialysate solution refilling flow path350as extending toward one opening end side of the dialysate solution refilling flow path350, and light is entered from the other end side of the light guide member facing the other opening end side of the dialysate solution refilling flow path350.

<Sterilization Method by Sterilization System>

Next, a sterilization method by the sterilization system1will be described together with operation of the dialysis device300. In the case of operating the dialysis device300, the blood pump321is operated to send the blood from the above-described shunt to the semipermeable membrane tubes332of the dialyzer330. Moreover, the patient monitoring device310supplies the dialysate solution to the housing space of the body case331of the dialyzer330through the dialysate solution flow path340A. Thus, in the housing space of the body case331of the dialyzer330, a substance moves between the blood and the dialysate solution through each semipermeable membrane tube332. Specifically, the waste such as urine toxin in the blood moves into the dialysate solution through the semipermeable membrane tubes332according to a concentration gradient. Moreover, components such as red blood cells, white blood cells, and protein in the blood flow in the tubes without penetrating the semipermeable membrane tubes332. In a case where an electrolyte concentration in the blood is higher than an electrolyte concentration in the dialysate solution, an electrolyte in the blood moves into the dialysate solution through the semipermeable membrane tubes332according to a concentration gradient. In a case where the electrolyte concentration in the blood is lower than the electrolyte concentration in the dialysate solution, the electrolyte moves into the blood through the semipermeable membrane tubes332according to the concentration gradient. Similarly, in a case where a glucose concentration in the blood is higher than a glucose concentration in the dialysate solution, glucose in the blood moves into the dialysate solution through the semipermeable membrane tubes332according to a concentration gradient. In a case where the glucose concentration in the blood is lower than the glucose concentration in the dialysate solution, the glucose moves into the blood through the semipermeable membrane tubes332according to the concentration gradient.

The dialysate solution containing the waste moved from the blood is, as waste fluid, recovered from the housing space of the body case331by the patient monitoring device310through a downstream-side dialysate solution flow path340B. Moreover, the blood from which the waste has been removed by the dialyzer330flows into the blood of the dialysis patient from each semipermeable membrane tube332through the vein-side blood circuit320B.

At this point, in the present embodiment, the dialysate solution refilling pump351is operated to send the dialysate solution branched from the dialysate solution flow path340A to the artery-side blood circuit320A through the dialysate solution refilling flow path350. In this manner, the blood sent to the semipermeable membrane tubes332of the dialyzer330through the shunt is diluted with the dialysate solution.

As described above, the dialysate solution refilling flow path350is provided with the light introduction device3.FIG. 14is a view of an operation state of the light introduction device3in the present embodiment as inFIG. 6. As illustrated inFIG. 14, in the light introduction device3of the present embodiment, a first LED42A and a second LED42B are, as in the light introduction device of the first embodiment, turned on to emit ultraviolet light from the first LED42A and the second LED42B. As in the first embodiment, such ultraviolet light enters the light guide member50through the entrance-side end portion50A thereof, and propagates toward the emitting-side end portion50B of the light guide member50. Large part of the light propagating to the emitting-side end portion50B is reflected on the emitting-side end portion50B, and enters the medical conduit in a state diagonally to a longitudinal direction of the medical conduit forming the dialysate solution refilling flow path350. The dialysate solution as liquid is introduced into an inner cavity of the medical conduit of the present embodiment. A difference between the refractive index of a thick portion of the medical conduit and the refractive index of the dialysate solution is smaller than a difference between the refractive index of the thick portion of the medical conduit and the refractive index of atmospheric air. Thus, most of the ultraviolet light having entered the medical conduit is released to the dialysate solution as illustrated inFIG. 14. Thus, in a case where bacteria are present in the dialysate solution, these bacteria can be directly irradiated with the ultraviolet light. Note that when the refractive index of the thick portion of the medical conduit is lower than the refractive index of the dialysate solution as the liquid introduced into the inner cavity of the medical conduit, it is preferable because light easily enters the dialysate solution from the medical conduit.

As described above, according to the sterilization system1of the present embodiment, the liquid is introduced into the inner cavity of the medical conduit. Such liquid is a substance contacting an inner wall of the medical conduit. Light can propagates in the substance through the medical conduit, and bacteria present in the liquid can be deactivated such that the amount of the bacteria is decreased. Thus, a sterilization effect for the liquid introduced into the human body can be enhanced.

Note that in the present embodiment, the light introduction device3is provided at the dialysate solution refilling flow path350, and the dialysate solution refilling flow path350and the light introduction device3form the sterilization system1. However, a location where the light introduction device3is provided is not limited to above. For example, the light introduction device3may be provided at the dialysate solution flow path340A, and the dialysate solution flow path340A and the light introduction device3form the sterilization system.

Next, a sixth embodiment will be described. Note that the same reference numerals are used to represent configurations similar to those described in the first embodiment, and unless otherwise described, overlapping description will be omitted.

FIG. 15is a view of an outline configuration of an infusion device including a sterilization system in the sixth embodiment. That is, the sterilization system1of the present embodiment is part of an infusion device400. The infusion device400of the present embodiment includes, as main components, an infusion solution bag410and an infusion tube420as a medical conduit.

The infusion solution bag410is filled with a chemical solution. Moreover, one end of the infusion tube420is connected to a lower portion of the infusion solution bag410, and a not-shown infusion needle is provided at the other end of the infusion tube420. The infusion tube420is a path allowing passage of the chemical solution of the infusion solution bag410, and includes a tube having elasticity. In the present embodiment, the infusion tube420has a configuration similar to that of the catheter2as the medical conduit of the first embodiment. Thus, the chemical solution in the infusion solution bag410is introduced into a human body through the infusion tube. Note that the infusion tube420may be provided with an infusion cylinder.

Moreover, in the infusion device400of the present embodiment, the infusion tube420is provided with a light introduction device3. The light introduction device3has a configuration similar to that of the light introduction device3in the first embodiment. Thus, as in the light introduction device3fixed to the catheter2in the first embodiment, the light introduction device3of the present embodiment is fixed to the infusion tube420. Thus, in the present embodiment, the infusion tube420and the light introduction device3form the sterilization system1.

As in the light introduction device of the first embodiment, ultraviolet light is, in the infusion device400, entered to the infusion tube420as the medical conduit from the light introduction device3in the middle of infusion. Specifically, as in entrance of the ultraviolet light from the light introduction device3to the medical conduit in the fifth embodiment described with reference toFIG. 14, the ultraviolet light is entered from the light introduction device3to the infusion tube420. As in entrance of the ultraviolet light from the medical conduit to the dialysate solution in the fifth embodiment, the ultraviolet light having entered the infusion tube420is released from the infusion tube420to the chemical solution introduced into an inner cavity of the infusion tube420. Thus, in a case where bacteria are present in the chemical solution, these bacteria can be directly irradiated with the ultraviolet light. Note that when the refractive index of a thick portion of the infusion tube420is lower than the refractive index of the chemical solution as liquid introduced into the inner cavity of the infusion tube420, it is preferable because light easily enters the chemical solution from the infusion tube420.

As described above, in the present embodiment, light can propagate, as in the sterilization system1of the fifth embodiment, in the chemical solution as a substance contacting an inner wall of the infusion tube420, and the bacteria present in the chemical solution can be deactivated such that the amount of the bacteria is decreased. Thus, a sterilization effect for the liquid introduced into the human body can be enhanced.

The embodiments of the present invention have been described above by way of example, but may be modified as necessary.

For example, in the above-described embodiments, the catheter2having the portion where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95% is used as the medical conduit. However, instead of the catheter2, a catheter having no portion where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95% may be used.

Moreover, in the above-described embodiments, the zone from the opening end2A of the catheter2on the human body outer side to the boundary position between the human tissue arrangement portion23and the intracorporeal arrangement portion21is applied as the first zone SC1where the transmission for the ultraviolet light per millimeter in length is equal to or higher than 95%. However, e.g., a first zone may be applied, in which a middle section from the opening end2A of the catheter2on the human body outer side to the human tissue arrangement portion23is a start position of the first zone SC1and the boundary position between the human tissue arrangement portion23and the intracorporeal arrangement portion21is an end position of the first zone SC1. Alternatively, the end position of the first zone SC1may be, for example, a middle section of the intracorporeal arrangement portion21. Alternatively, only the human tissue arrangement portion23may be applied as the first zone, for example. As described above, the first zone including the section of the catheter2surrounded by the human tissue10and the second zone other than the first zone can be applied.

Further, only part of the human tissue arrangement portion23may be taken as the first zone. For example, a portion of the human tissue arrangement portion23after the external cuff24A or the internal cuff24B may be applied as the first zone. Alternatively, the entirety of the catheter2may be taken as the first zone, and the second zone may be omitted. In other words, the transmission for the ultraviolet light per millimeter in length may be equal to or higher than 95% at at least part of the section of the catheter2surrounded by the human tissue10.

Note that in a case where the first zone includes at least part of the intracorporeal arrangement portion21, bacteria in liquid stored in an inner cavity of the intracorporeal arrangement portion21can be sterilized such that the amount of the bacteria is decreased.

In addition, in the above-described embodiments, the surface of the catheter2is not processed, but the following processing may be performed.FIG. 16is an enlarged view of a portion surrounded by a chain line ofFIG. 2, illustrating a state in which the surface of the catheter2is processed. For example, as illustrated inFIG. 16, a recessed-raised portion25may be provided at the surface of the human tissue arrangement portion23. Note that the recessed-raised portion25may be also provided at the surface of the portion of the human tissue arrangement portion23provided with the external cuff24A and the internal cuff24B. With this configuration, the amount of light released from the human tissue arrangement portion23to the human tissue10can be adjusted.

Note that a height difference D1at the recessed-raised portion25is preferably substantially equal to the light source wavelength, or is preferably about ten times as great as the light source wavelength. The height difference D1may be within a range of 200 nm to 2 μm. Moreover, as illustrated inFIG. 16, in a case where the height difference D1increases with a distance from the opening end2A of the catheter2on the human body outer side, light can be uniformly released along the longitudinal direction of the catheter2.

In addition to the height difference D1or instead of the height difference D1, the density of the recessed-raised portion25per unit area may increase with a distance from the opening end2A of the catheter2on the human body outer side. Specifically, in a case where the intensity of light released per square area of 1 cm in length and 1 cm in width is, for example, a predetermined value such as 1 mW, one or both of the height difference and the density increase with a distance from the opening end2A of the catheter2on the human body outer side such that the intensity of light released per square area is the predetermined value even with any distance from the opening end2A on the human body outer side. Alternatively, one or both of the height difference D1and the density of the recessed-raised portion25at the portion provided with the cuff24may be greater than one or both of the height difference D1and the density of the recessed-raised portion25at other portions. With this configuration, the cuff24having such tendency that bacteria are easily accumulated at the cuff24can be irradiated with the ultraviolet light in a focused manner.

Further, in addition to the recessed-raised portion25or instead of the recessed-raised portion25, multiple reflectors dispersed at the surface of the human tissue arrangement portion23may be provided at such a surface. A metal thin film made of aluminum or silver may be utilized as the reflector, and the reflectors may be in a dot pattern. With this configuration, the amount of light released from the human tissue arrangement portion23to the human tissue10can be adjusted. Note that in the case of providing the reflectors in addition to the recessed-raised portion25, a predetermined amount of light released from the human tissue arrangement portion23to the human tissue10can be ensured while the light can more easily propagate to a lumen side of the human body.

In a case where the percentage of a reflection film per unit area of the catheter2decreases with a distance from the opening end of the catheter2on the human body outer side, these reflectors can ensure the predetermined amount of light released from the human tissue arrangement portion23to the human tissue10while more easily adjusting light propagation to the lumen side of the human body.

Moreover, in the above-described embodiments, no member configured to trap the ultraviolet light in the catheter2is provided, but such a member may be provided. Specifically, one or both of outer and inner surfaces of the extracorporeal arrangement portion22are, for example, coated or applied with a member such as a reflection film configured to reflect the ultraviolet light. With this configuration, more ultraviolet light can be guided from the extracorporeal arrangement portion22to the human tissue arrangement portion23.

Further, in the above-described embodiments, no member configured to visually check the ultraviolet light is provided at the catheter2, but such a member may be provided. Specifically, the outer surface of the extracorporeal arrangement portion22is, for example, coated or applied with a light emission member configured to emit visible light by the ultraviolet light. Note that a through-hole penetrating the housing30from an outer surface to an inner surface thereof may be provided at the third tube portion PT3of the housing30, and the member configured to emit the visible light may be provided in the through-hole.

In addition, in the above-described embodiments, the peritoneal dialysis catheter2is applied as the medical conduit. However, other catheters such as a urinary catheter can be applied as the medical conduit. Moreover, a drain may be applied as the medical conduit.

Moreover, in the above-described embodiments, the light introduction device3is detachable from the catheter2. However, the light introduction device3may be fixed to the catheter2. Note that the light introduction device3is preferably detachable from the catheter2, considering that the light introduction device3is replaced with the catheter2remaining in the human body.

Further, in the above-described embodiments, the housing30, the light emitter40, and the light guide member50are provided as the components of the light introduction device3. However, some of the components of the light introduction device3may be omitted. For example, the housing30may be omitted, and the light guide member50attached to the light emitter40may be detachable from the catheter2in a state in which the end surface of the entrance-side end portion50A of the light guide member50and a light emission surface of the light emitter40contact each other. Note that the catheter2having the portion where the light transmission for the wavelength band of 270 nm to 340 nm per millimeter in length is equal to or higher than 95% may be the component of the light introduction device3. Moreover, the third tube portion PT3of the light introduction device3may also serve as the connector2CN.

In addition, in the above-described embodiments, the light introduction device3is provided on the side surface of the end portion of the catheter2on the human body outer side, and light is introduced through such a side surface. However, the light introduction device may be, for example, provided at a tip end of the opening end2A of the catheter2on the human body outer side, and light may be introduced into the catheter2through the opening end2A. Alternatively, the light introduction device may be, for example, provided at the middle section of the extracorporeal arrangement portion22of the catheter2, and light may be introduced through a side surface of the middle section. Note that the light introduction device3is preferably provided at a spot of the extracorporeal arrangement portion22of the catheter2apart from an outlet portion of the subcutaneous tunnel by, e.g., 1 cm or longer, considering that the probability of entrance of bacteria through the outlet portion upon, e.g., attachment of the light introduction device3to the catheter2is reduced.

Moreover, in the above-described embodiments, the ultraviolet light is introduced into the catheter2from the light introduction device3, but visible light may be introduced together with such light. Specifically, in the first embodiment, an LED configured to emit the visible light is provided together with the LEDs42, and the ultraviolet light and the visible light are emitted from the LED and the LEDs42to the entrance-side end portion50A of the light guide member50, for example. Moreover, in the second embodiment, the ultraviolet light and the visible light are generated by the light source144, and these types of light are emitted to the entrance-side end portion50A of the light guide member50through the optical fibers143A,143B, for example. Note that other light than the ultraviolet light may be introduced, but the ultraviolet light is preferable considering enhancement of the sterilization ability.

In the above-described fifth and sixth embodiments, the light introduction device3of the first embodiment is provided at the medical conduit, but the light introduction device3of the second embodiment or the light introduction device100of the fourth embodiment may be provided at the medical conduit, for example.

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