JP7707582B2 - Indwelling needle assembly - Google Patents

Description

The present invention relates to an indwelling needle assembly that is inserted into a blood vessel during infusion, blood sampling, artificial dialysis, etc.

Conventionally, there has been known an indwelling needle assembly that is inserted into a blood vessel during infusion, blood collection, artificial dialysis, etc. As shown in JP 2007-136246 A (Patent Document 1), the indwelling needle assembly has a structure in which an inner needle is inserted into an outer needle in a retractable manner, and an inner needle hub provided on the base end side of the inner needle and an outer needle hub provided on the base end side of the outer needle are combined with each other. Then, by inserting the outer needle together with the inner needle into a blood vessel and then withdrawing the inner needle from the outer needle, the indwelling needle having the outer needle and the outer needle hub is left in a state of being inserted into the blood vessel.

In Patent Document 1, a valve body that switches between communicating and blocking the outer needle hub is provided inside the outer needle hub. The valve body blocks the inside of the outer needle hub when the inner needle is inserted into the outer needle. When a syringe or the like is connected to the outer needle hub that is left in place with the outer needle inserted into a blood vessel, the valve body is opened and the outer needle hub is switched to a communicating state.

JP 2007-136246 A

However, in the structure of Patent Document 1, when the inner needle is inserted into the outer needle, the inner cavity of the outer needle is substantially blocked by the inner needle. Therefore, even if the outer needle inserted into the inner needle is inserted into a blood vessel, blood is not easily introduced into the space distal to the valve body inside the outer needle hub, and air is likely to remain in the space. Therefore, when the inner needle is pulled out from the outer needle and an infusion or medicinal solution is administered into a blood vessel through the retained outer needle and outer needle hub, it is thought that a relatively large amount of air will be mixed into the infusion or medicinal solution.

In addition, in Patent Document 1, even if the inner cavity of the outer needle is opened by removing the inner needle from the outer needle, the space inside the outer needle hub distal to the valve body is not open to the outside except for the inner cavity of the outer needle, and the discharge of air to the outside is not taken into consideration. Therefore, when the valve body is in a closed state, the introduction of blood into the outer needle hub is restricted by air pressure, and air is likely to remain in the space inside the outer needle hub distal to the valve body.

The problem to be solved by the present invention is to provide an indwelling needle assembly with a novel structure that makes it difficult for air to remain inside the outer needle hub distal to the valve body.

The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is merely an example, and may be combined with one another as appropriate. The multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various alternative embodiments may be realized.

The first aspect is an indwelling needle assembly in which a hollow inner needle having an inner needle hub on the base end side is inserted removably into an outer needle having an outer needle hub on the base end side, and a valve body that switches between communication and blocking of the outer needle hub is disposed inside the outer needle hub, and an outflow opening and a reflux opening are formed through the peripheral wall of the inner needle, and the reflux opening, which is provided proximally to the outflow opening, opens into the interior of the outer needle hub distal to the valve body.

According to the indwelling needle assembly structured according to this aspect, blood flowing into the inside of the inner needle can be guided to the inside of the outer needle at the outflow opening, thereby guiding the blood to a space distal to the valve body inside the outer needle hub. In addition, since the return opening of the inner needle opens distal to the valve body inside the outer needle hub, when air inside the outer needle hub is pushed out by blood, air flows from the return opening into the inside of the inner needle and is discharged from the base end opening of the inner needle. This allows air to be discharged from the space distal to the valve body inside the outer needle hub, reducing the amount of air remaining in the space. As a result, when infusion or medicinal liquid is administered into a blood vessel through the inside of the outer needle hub, the intrusion of air is suppressed, improving safety.

The second aspect is the indwelling needle assembly described in the first aspect, in which the distance between the reflux opening and the valve body is closer than the distance between the reflux opening and the distal end of the outer needle hub.

In an indwelling needle assembly constructed according to this embodiment, the return opening is located closer to the valve body, making it less likely for the return opening to be blocked by blood when blood is introduced distally into the interior of the outer needle hub, and making it easier for air to be discharged into the interior of the inner needle through the return opening.

The third aspect is an indwelling needle assembly according to the first or second aspect, in which a narrowed portion is provided between the outflow opening and the return opening to partially reduce the cross-sectional area of the inner lumen of the inner needle.

With an indwelling needle assembly constructed according to this embodiment, blood that has flowed into the inner needle is blocked by the narrowed portion, making it easier for the blood to flow out of the outer needle at the outlet opening. This allows blood to flow efficiently into the interior of the outer needle hub. In addition, because the narrowed portion is provided between the outlet opening and the return opening, the narrowed portion does not prevent air that has entered the inner needle from the return opening from being discharged to the base end side.

The fourth aspect is an indwelling needle assembly in which a hollow inner needle having an inner needle hub on the base end side is inserted removably into an outer needle having an outer needle hub on the base end side, and a valve body that switches between communication and blocking of the outer needle hub is disposed inside the outer needle hub, an outlet opening and a reflux opening are formed penetrating the peripheral wall of the inner needle, the reflux opening is located proximal to the outlet opening and distal to the valve body, a crushed portion is provided in which the inner needle is crushed between the outlet opening and the reflux opening in the axial direction, and a protector engagement portion that engages with a needle tip protector that protects the needle tip of the inner needle when the inner needle is pulled out from the outer needle is provided on the inner needle by radial bulging accompanying crushing of the inner needle at the crushed portion.

According to the indwelling needle assembly constructed according to this aspect, blood flowing into the inner needle is allowed to flow out through the outflow opening into the outer needle or the outer needle hub, thereby directing blood to a space inside the outer needle hub that is distal to the valve body. In addition, when air inside the outer needle hub is pushed out by blood, air flows from the return opening into the lumen of the inner needle, and the air is discharged from the base end opening of the inner needle. This allows air to be discharged from the space inside the outer needle hub that is distal to the valve body, thereby reducing the amount of air remaining in the space. As a result, when infusion or medicinal liquid is administered into a blood vessel through the inside of the outer needle hub, the intrusion of air is suppressed, improving safety.

A crushed portion is provided between the outflow opening and the return opening, and the lumen of the inner needle is narrowed at the crushed portion. Therefore, blood flowing through the inner needle is blocked by the crushed portion, and is easily allowed to flow out through the outflow opening into the outer needle or the outer needle hub. Therefore, blood can be efficiently allowed to flow into the interior of the outer needle hub. In addition, because the crushed portion is provided between the outflow opening and the return opening, the crushed portion does not prevent air that has entered the inner needle from the return opening from being discharged to the base end side.

The crushed portion is formed by partially crushing the inner needle, so that the inner needle bulges in a direction perpendicular to the crushing direction at the crushed portion. By using this bulging portion as a protector engagement portion that engages with the needle tip protector when the inner needle is pulled out, the crushed portion and the protector engagement portion can be formed simultaneously, reducing the number of manufacturing steps.

In the fifth aspect, in the indwelling needle assembly described in any one of the first to fourth aspects, the outflow opening and the return opening are open continuously over at least half the circumference of the inner needle.

In an indwelling needle assembly constructed according to this aspect, the outflow opening is a wide opening that opens over more than half the circumference of the inner needle in the circumferential direction, so that the amount of blood flowing out into the outer needle or the outer needle hub can be secured. The return opening is a wide opening that opens over more than half the circumference of the inner needle in the circumferential direction, so that air is more easily guided to the return opening, and air in the outer needle hub can be more efficiently discharged.

The sixth aspect is an indwelling needle assembly in which a hollow inner needle having an inner needle hub on the base end side is inserted removably into an outer needle having an outer needle hub on the base end side, and a valve body that switches between communication and blocking of the outer needle hub is disposed inside the outer needle hub, the valve body is formed with a needle insertion hole through which the inner needle is inserted, and an exhaust hole that penetrates the valve body is formed between the inner needle and the needle insertion hole when the inner needle is inserted into the needle insertion hole.

According to the indwelling needle assembly constructed according to this embodiment, an exhaust hole is formed in the valve body, so that the internal region distal to the valve body in the outer needle hub and the internal region proximal to the valve body are connected by the exhaust hole. Therefore, when blood or the like is introduced into the outer needle hub, air in the region distal to the valve body in the outer needle hub is discharged through the exhaust hole to the proximal region, making it possible to fill the internal region distal to the valve body with blood or the like. As a result, when infusion or medicinal liquid or the like is administered into a blood vessel through the inside of the outer needle hub, the intrusion of air is suppressed, improving safety.

In order to prevent blood from passing through, it is desirable for the exhaust hole to have a small cross-sectional area and minimum width, but the hole formed during molding of the valve body could not have a cross-sectional area or minimum width small enough to be required for the exhaust hole. Therefore, by focusing on the fact that the needle insertion hole is narrowed by the insertion of the inner needle, and forming the exhaust hole by utilizing the narrowed area between the inner needle and the inner surface of the needle insertion hole, it is possible to realize an exhaust hole that is too small to be formed during molding of the valve body.

The seventh aspect is the indwelling needle assembly described in the sixth aspect, in which the valve body is provided with a needle placement section in which the inner needle is placed and a recessed groove that opens into the inner peripheral surface of the needle placement section and penetrates in the needle axial direction, and the groove cross-sectional area of the recessed groove is smaller than the hole cross-sectional area of the needle placement section.

In an indwelling needle assembly constructed according to this aspect, by forming a groove that opens into the inner peripheral surface of the needle placement section, an exhaust hole is formed in the portion where the groove is formed, even if the outer peripheral surface of the inner needle is in contact with the inner peripheral surface of the needle placement section at a portion that is not in contact with the opening of the groove. Therefore, it is possible to provide an exhaust hole that utilizes the needle insertion hole while preventing the inner needle from rattling by contacting the valve body on the inner surface of the needle placement section.

The eighth aspect is the indwelling needle assembly described in the seventh aspect, in which a plurality of the grooves are formed in the circumferential direction of the needle placement portion.

In an indwelling needle assembly constructed according to this embodiment, for example, the inner needle comes into contact with the valve body between the circumferential grooves, and the grooves form multiple exhaust holes independently. This makes it possible to efficiently exhaust air by ensuring a large total cross-sectional area of the multiple exhaust holes while restricting the passage of blood by reducing the cross-sectional area and minimum width dimension of each exhaust hole.

The ninth aspect is an indwelling needle assembly in which a hollow inner needle having an inner needle hub on the base end side is inserted removably into an outer needle having an outer needle hub on the base end side, and a valve body that switches between communication and blocking of the outer needle hub is disposed inside the outer needle hub, the valve body has an opening that penetrates in the needle axial direction of the inner needle, the valve body is disposed inside the outer needle hub in a state compressed radially by the outer needle hub, the opening is reduced by radial compression of the valve body, and the reduced opening forms an exhaust hole that penetrates the valve body.

According to the indwelling needle assembly constructed according to this embodiment, an exhaust hole is formed in the valve body, so that the internal region distal to the valve body in the outer needle hub and the internal region proximal to the valve body are connected by the exhaust hole. Therefore, when blood or the like is introduced into the outer needle hub, air in the region distal to the valve body in the outer needle hub is discharged through the exhaust hole to the proximal region, making it possible to fill the internal region distal to the valve body with blood or the like. As a result, when infusion or medicinal liquid or the like is administered into a blood vessel through the inside of the outer needle hub, the intrusion of air is suppressed, improving safety.

The exhaust hole is formed when the opening formed in the valve body is reduced by deformation caused by compression of the valve body. Therefore, it is possible to form an exhaust hole that is smaller than the smallest opening that can be formed in the valve body, and blood leakage through the exhaust hole can be suppressed. Furthermore, the reduction in the opening is achieved by compressing the valve body in the radial direction when the valve body is attached to the outer needle hub. Therefore, there is no need to provide a special part for reducing the opening or to perform special work to reduce the opening, and a valve body with an exhaust hole can be easily obtained.

In the tenth aspect, in the indwelling needle assembly described in the ninth aspect, the opening includes a main opening and a groove-shaped sub-opening that opens on the inner peripheral surface of the main opening and penetrates the valve body in the needle axis direction of the inner needle, and the main opening is closed by radial compression of the valve body, and the exhaust hole is formed by the sub-opening.

According to the indwelling needle assembly constructed according to this embodiment, the main opening of the opening is closed by radial compression caused by attachment of the valve body to the outer needle hub, making it easier to obtain a smaller exhaust hole. Even when the main opening is closed, a connected exhaust hole is ensured by the groove-shaped sub-opening that opens to the inner peripheral surface of the main opening, so that air can be effectively discharged through the exhaust hole. Because the sub-opening is groove-shaped, it can be formed with a smaller cross-sectional area than the through hole, and the cross-sectional area of the exhaust hole formed by the sub-opening can be made smaller.

The eleventh aspect is an indwelling needle assembly according to the ninth or tenth aspect, in which the valve body is formed in an elliptical plate shape when in a stand-alone state, and the valve body is compressed in the longitudinal direction by being placed inside the outer needle hub having a circular cross section, thereby reducing the opening of the valve body.

With an indwelling needle assembly constructed in accordance with this aspect, it is easy to determine the compression direction when the valve body is attached to the outer needle hub, and the contraction deformation of the opening is stabilized, making it easier to obtain a uniform exhaust hole.

The twelfth aspect is an indwelling needle assembly in which a hollow inner needle having an inner needle hub on the base end side is inserted removably into an outer needle having an outer needle hub on the base end side, and a valve body that switches between communication and blocking of the outer needle hub is disposed inside the outer needle hub, and the valve body includes a first valve member and a second valve member that are overlapped in the needle axial direction of the inner needle, a first through hole is formed in the first valve member and a second through hole is formed in the second valve member, and the first through hole and the second through hole are positioned apart from each other in the axial view, and a narrowing groove is formed on at least one of the overlapping surfaces of the first valve member and the second valve member, extending across the first through hole and the second through hole, and the first through hole, the second through hole, and the narrowing groove form an exhaust hole that penetrates the valve body, and the groove cross-sectional area of the narrowing groove is smaller than the hole cross-sectional areas of the first through hole and the second through hole.

According to the indwelling needle assembly constructed according to this embodiment, an exhaust hole is formed in the valve body, so that the internal region distal to the valve body in the outer needle hub and the internal region proximal to the valve body are connected by the exhaust hole. Therefore, when blood or the like is introduced into the outer needle hub, air in the region distal to the valve body in the outer needle hub is discharged through the exhaust hole to the proximal region, making it possible to fill the internal region distal to the valve body with blood or the like. As a result, when infusion or medicinal liquid or the like is administered into a blood vessel through the inside of the outer needle hub, the intrusion of air is suppressed, improving safety.

The flow resistance of the exhaust hole can be adjusted by adjusting the cross-sectional area and minimum width dimension of the narrowing groove extending between the overlapping surfaces of the first and second valve members to allow the passage of air and restrict the passage of blood.

The present invention makes it difficult for air to remain inside the outer needle hub distal to the valve body.

FIG. 1 is a cross-sectional view showing an indwelling needle assembly according to a first embodiment of the present invention. FIG. 2 is a plan view showing a tip portion of an inner needle constituting the indwelling needle assembly of FIG. FIG. 2 is an enlarged cross-sectional view of a portion of the indwelling needle assembly of FIG. 1, illustrating a state in which the inner needle unit has been separated from the indwelling needle. FIG. 13 is a perspective view of a valve body constituting an indwelling needle assembly according to a second embodiment of the present invention. FIG. 5 is a front view of the valve body shown in FIG. FIG. 13 is a front view of a valve body constituting an indwelling needle assembly according to a third embodiment of the present invention. FIG. 7 is a front view showing the valve body shown in FIG. 6 attached to the outer needle hub. FIG. 13 is a front view of a valve body constituting an indwelling needle assembly according to a fourth embodiment of the present invention. FIG. 9 is a front view showing the valve body shown in FIG. 8 attached to the outer needle hub. FIG. 13 is an exploded perspective view of a valve body constituting an indwelling needle assembly according to a fifth embodiment of the present invention. FIG. 11 is a vertical cross-sectional view of the valve body shown in FIG.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 shows an indwelling needle assembly 10 according to a first embodiment of the present invention. The indwelling needle assembly 10 has a structure in which the inner needle 14 constituting the inner needle unit 12 is retractably inserted into the outer needle 18 constituting the indwelling needle 16, combining the inner needle unit 12 with the indwelling needle 16. In the following description, in principle, the up-down direction refers to the up-down direction in Figure 1, and the left-right direction refers to the direction perpendicular to the paper surface of Figure 1. The tip side refers to the left side in Figure 1, which is the distal side, and the base side refers to the right side in Figure 1, which is the proximal side.

The inner needle unit 12 has a structure in which an inner needle hub 20 is fixed to an inner needle 14. The inner needle 14 is a hard member made of metal or the like, and in this embodiment is a hollow needle with an inner cavity 21. The tip of the inner needle 14 has a tip surface cut into an inclined shape, and a sharp needle tip 22 is formed as shown in Figures 1 and 2.

As shown in FIG. 1, the tip of the inner needle 14 is provided with a narrowing portion 24 that partially narrows the inner cavity 21. The narrowing portion 24 in this embodiment is a crushed portion formed by partially squashing the hollow inner needle 14 in the needle axial direction. In addition, the narrowing portion 24 in this embodiment is formed by pressing the inner surface of the inner needle 14 in the vertical direction, and the narrowing portion 24 blocks the inner cavity 21 of the inner needle 14 so that blood does not pass through. However, the narrowing portion 24 only needs to narrow the inner cavity 21 to reduce the cross-sectional area of the hole and restrict the passage of blood, and does not necessarily need to block the inner cavity 21 so that blood does not pass through it. The structure of the narrowing portion 24 is not limited as long as it narrows the inner cavity 21 of the inner needle 14. For example, the narrowing portion may be formed by disposing a separate plug member in the inner cavity 21.

As shown in FIG. 2, the tip of the inner needle 14 is formed with a pair of locking projections 26, 26 that protrude from the outer circumferential surface. The locking projections 26 as protector locking portions protrude in the left-right direction (the up-down direction in FIG. 2). In this embodiment, when the inner needle 14 is pressed vertically to form the narrowed portion 24, the pressed inner needle 14 bulges out on both sides in the left-right direction at the narrowed portion 24, thereby forming the locking projections 26, 26. However, the locking projections 26 can also be provided independently of the narrowed portion 24, and can be formed, for example, by pressing vertically both left and right ends of the hollow portion of the inner needle 14 to such an extent that the inner cavity 21 of the inner needle 14 is not narrowed.

The inner needle 14 is formed with a distal outflow opening 28 and a proximal return opening 30. The outflow opening 28 and the return opening 30 are formed by penetrating the peripheral wall of the inner needle 14 at the upper part. The outflow opening 28 and the return opening 30 communicate with the inner cavity 21 of the inner needle 14 and the outside of the inner cavity 21. In this embodiment, the outflow opening 28 and the return opening 30 have approximately the same opening shape and size, but for example, the outflow opening 28 and the return opening 30 can be made to have different shapes and sizes. The outflow opening 28 and the return opening 30 are preferably open over at least half the circumference of the inner needle 14, and in this embodiment, they are open in the upper half of the inner needle 14 over half the circumference. The return opening 30 is arranged proximally away from the outflow opening 28. The outflow opening 28 is formed on the distal side of the narrowed portion 24 of the inner needle 14, and in this embodiment, the distance from the narrowed portion 24 is closer than the distance from the needle tip 22. The reflux opening 30 is formed on the proximal side of the narrowed portion 24 of the inner needle 14, and is located distally of a valve body 70, which will be described later, when the inner needle 14 is inserted into the outer needle 18, which will be described later. When the inner needle 14 is inserted into the outer needle 18, the distance from the reflux opening 30 to the valve body 70 is closer than the distance from the tip of the outer needle hub 42.

As shown in FIG. 1, the inner needle hub 20 includes a hub body 32. The hub body 32 has a tip portion that is approximately rectangular tubular and a base portion that is approximately cylindrical. The tip portion of the hub body 32 has an outer circumferential surface that is curved in the axial direction and has a small diameter from both ends in the axial direction toward the center, making it difficult for the fingers to slip in the axial direction when the hub body 32 is held by the fingers and moved in the axial direction. The hub body 32 is integrally provided with an approximately cylindrical inner needle holding portion 34 that protrudes from the inner circumferential surface of the tip portion and extends toward the base end. The inner circumferential surface of the inner needle holding portion 34 is fixed to the outer circumferential surface of the inner needle 14, and the hub body 32 is fixed to the inner needle 14. A flange-shaped portion 36 that protrudes toward the outer periphery is provided at the tip of the hub body 32, and the tip surface of the hub body 32 has a smaller inner diameter and a larger outer diameter than the base end surface of the outer needle hub 42 described later. In the inner needle unit 12, the outflow opening 28 and the return opening 30 of the inner needle 14 are both located distal to the inner needle hub 20 and exposed to the outside.

A cap member 38 is attached to the base end opening of the hub body 32. The cap member 38 is generally cylindrical. The cap member 38 has a tapered outer circumferential surface with a small diameter tip portion that narrows toward the tip, and is attached to the hub body 32 by fitting the tip portion to the base end opening of the hub body 32. A breathable filter 40 is attached to the base end opening of the cap member 38, and air inside the cap member 38 can be discharged to the outside through the breathable filter 40, while blood that enters the inside of the cap member 38 through the inner needle 14 due to flashback at the time of puncturing, for example, does not pass through the breathable filter 40 and does not leak out from the inside of the cap member 38. It is preferable that the cap member 38 is transparent or semi-transparent in order to make it easier to visually recognize flashback when the inner needle 14 punctures a blood vessel.

The indwelling needle 16 has a structure in which an outer needle hub 42 is provided at the base end of the outer needle 18. The outer needle 18 is a hollow needle formed from resin or metal. It is desirable that the outer peripheral surface of the tip portion of the outer needle 18 is a tapered surface that becomes smaller in diameter toward the tip. The inner diameter dimension of the tip of the outer needle 18 may be larger than or the same as the outer diameter dimension of the inner needle 14, but is preferably made smaller than the outer diameter dimension of the inner needle 14. With the inner needle 14 inserted through the outer needle 18, the tip of the outer needle 18 is fitted into the inner needle 14, and the inner needle 14 and the outer needle 18 are positioned to a certain extent.

The base end of the outer needle 18 is inserted into the inner circumference of the cylindrical outer needle hub 42 and fixed to the outer needle hub 42. The outer needle hub 42 is, for example, a cylindrical body made of resin. The outer needle hub 42 of this embodiment has a structure in which a needle fixing member 44 constituting the tip portion and a luer connection member 46 constituting the base portion are combined. However, the outer needle hub 42 may be composed of a single part as a whole, or may be composed of a combination of three or more parts. In addition, when the outer needle hub 42 is composed of multiple parts, the parts may be fixed by being fitted together without adhesion, or may be fixed by means of adhesion, welding, or the like.

The needle fixing member 44 is cylindrical overall and has a tapered section 48 in the axial direction that increases in diameter toward the base end, with the base end side from the tapered section 48 having a larger diameter than the tip end side. The needle fixing member 44 has engagement holes 50, 50 that penetrate in the vertical direction, and has a tapered inner circumferential surface that expands toward the base end from the engagement hole 50. The outer needle 18 is inserted into the tip portion of the needle fixing member 44, which has a small diameter, and the outer needle 18 is fixed to the needle fixing member 44 by a cylindrical pin.

The luer connection member 46 is generally cylindrical with a step in the axial direction, with the tip side of the step forming a large-diameter hub connection section 54 and the base end side forming a small-diameter luer insertion section 56. A pair of engagement claws 58, 58 are provided on the outer peripheral surface of the hub connection section 54, and these engagement claws 58, 58 engage with the inner surfaces of engagement holes 50, 50 provided in the needle fixing member 44, thereby connecting the needle fixing member 44 and the luer connection member 46 to form the outer needle hub 42. The inner peripheral surface of the luer insertion section 56 is a luer taper that expands in diameter toward the base end.

The luer connection member 46 of the outer needle hub 42 accommodates a plunger 60. The plunger 60 is generally formed in a stepped cylindrical shape, and has a protector accommodation section 62 penetrating in the axial direction. The plunger 60 has an input section 64, which is a small-diameter tube, at its base end, and an action section 66, which is a large-diameter tube, at its tip end. The input section 64 and the action section 66 are continuously and integrally formed in a stepped shape. The inner peripheral surface shape of the plunger 60 is a rectangle at the input section 64, which corresponds to the needle insertion section 80 of the needle tip protector 78 described later, and is a circle at the action section 66. The inner peripheral surface shape of the input section 64 is not limited to a rectangle, but is preferably an elliptical or polygonal shape in which the inner diameter dimension changes in the circumferential direction so as to prevent the needle tip protector 78 from rotating. The plunger 60 may be appropriately provided with slits (holes) penetrating the peripheral wall. In addition, by making the inner peripheral surface shape of the action part 66 flat in the left-right direction, the needle tip protector 78, whose outer dimension in the up-down direction is larger than that in the left-right direction, can be accommodated in the protector accommodation part 62 formed on the inner circumference of the action part 66 with space efficiency.

The input portion 64 of the pusher 60 is housed in the luer insertion portion 56 of the luer connection member 46, and the action portion 66 is housed in the hub connection portion 54 of the luer connection member 46. The outer peripheral surface of the action portion 66 is overlapped with the inner peripheral surface of the hub connection portion 54 of the outer needle hub 42, so that the pusher 60 is positioned in the axial direction perpendicular to the outer needle hub 42. In addition, the outer diameter dimension of the action portion 66 is larger than the inner diameter dimension of the luer insertion portion 56, and the base end surface of the action portion 66 is overlapped with the step of the luer connection member 46, so that the pusher 60 is positioned in the axial direction relative to the outer needle hub 42. The base end of the pusher 60 is located on the tip side of the base end of the outer needle hub 42 (lure connection member 46), and the pusher 60 is housed without protruding from the outer needle hub 42 to the base end.

A valve body 70 is disposed on the tip side of the plunger 60 inside the outer needle hub 42. The valve body 70 is formed of a resin elastomer or rubber having rubber-like elasticity. The valve body 70 is substantially disk-shaped, and is disposed so as to close the inside of the outer needle hub 42 by having its outer peripheral end sandwiched in the thickness direction between the needle fixing member 44 and the luer connection member 46 that constitute the outer needle hub 42. This divides the inside of the outer needle hub 42 into a first region 72 on the tip side of the valve body 70 and a second region 74 on the base side of the valve body 70.

As shown in FIG. 1, the valve body 70 has a slit 76 penetrating the inner periphery. The slit 76 extends radially from the center of the valve body 70, for example, and penetrates the valve body 70 in the left-right direction in FIG. 1, which is the needle axis direction of the inner needle 14. In this embodiment, the slit 76 is substantially Y-shaped extending radially in three directions from the center of the valve body 70 toward the outer periphery, but may be, for example, a straight line extending radially to both sides or a cross shape extending in four directions. The inside of the outer needle hub 42 is switched between a communication state in which the first region 72 and the second region 74 are mutually communicated through the slit 76 and a blocked state in which the first region 72 and the second region 74 are separated by the valve body 70, by opening and closing the slit 76 of the valve body 70.

As shown in FIG. 1, the tip outer peripheral edge of the action part 66 of the plunger 60 is located on the outer peripheral side of the outer peripheral end of the slit 76 of the valve body 70. As a result, at least the outer peripheral end of the tip surface of the plunger 60 is located on the outer peripheral side of the slit 76. More preferably, the tip inner peripheral edge of the action part 66 is located on the outer peripheral side of the outer peripheral end of the slit 76, and the entire tip surface of the action part 66 is located outside the slit 76 on the outer periphery. The tip of the plunger 60 may be in contact with the valve body 70 supported by the outer needle hub 42, but in this embodiment, it is located away from the base end of the valve body 70.

A needle tip protector 78 is accommodated in the protector accommodating section 62 provided inside the plunger 60. The needle tip protector 78 is formed, for example, from an elastically deformable metal plate. The needle tip protector 78 has a needle insertion section 80 at its base end that extends substantially perpendicular to the needle axial direction of the inner needle 14. The needle insertion section 80 is rectangular plate-shaped, and a circular hole 82 corresponding to the outer shape of the inner needle 14 is formed in the center, penetrating it in the thickness direction. The diameter of the circular hole 82 is larger than the outer diameter of the inner needle 14 at the portion detached from the locking projections 26, 26, and smaller than the outer diameter of the inner needle 14 at the portion where the locking projections 26, 26 are formed.

The needle tip protector 78 has a pair of needle tip protection parts 84a, 84b. The pair of needle tip protection parts 84a, 84b face each other vertically and extend from the upper and lower ends of the needle insertion part 80 toward the tip.

The needle tip protector 78 is housed inside the plunger 60. That is, the needle insertion portion 80 and the base end portions of the pair of needle tip protection portions 84a, 84b are inserted into the tip portion of the input portion 64 of the plunger 60. The tip portions of the pair of needle tip protection portions 84a, 84b are also inserted into the action portion 66 of the plunger 60. The base end portion of the needle tip protector 78 is inserted into the input portion 64, which has a rectangular inner circumferential cross-sectional shape and a small diameter, so that the needle tip protector 78 is positioned in the axis perpendicular direction and circumferential direction relative to the plunger 60, preventing rattling and positional deviation. In addition, the tip portion of the needle tip protector 78 is housed in the action portion 66, which has a wide internal space, so that the pair of needle tip protection portions 84a, 84b are housed in the plunger 60 while maintaining their initial shapes separated from each other.

The inner needle unit 12 and the indwelling needle 16 are combined with each other to form the indwelling needle assembly 10. That is, the inner needle 14 is inserted into the indwelling needle 16 from the base end side so as to be retractable, and penetrates the indwelling needle 16 so that the needle tip 22 protrudes from the tip opening of the outer needle 18. The inner needle hub 20 of the inner needle unit 12 is abutted from the base end side against the base end surface of the outer needle hub 42 in the axial direction, thereby defining the amount by which the inner needle 14 protrudes from the outer needle 18 to the tip.

The inner needle 14 penetrates the needle tip protector 78. That is, the inner needle 14 inserted into the indwelling needle 16 from the base end side is inserted into the circular hole 82 of the needle insertion portion 80 of the needle tip protector 78 and penetrates between the tip portions of the pair of needle tip protection portions 84a, 84b toward the tip side. The pair of needle tip protection portions 84a, 84b are spaced apart in the vertical direction relative to the inner needle 14, and when the inner needle 14 moves in the axial direction relative to the needle tip protector 78, frictional resistance due to contact between the inner needle 14 and the pair of needle tip protection portions 84a, 84b is not generated, and the inner needle 14 can move smoothly. In addition, since the pair of needle tip protection parts 84a, 84b are arranged at a distance greater than the vertical width dimension of the inner needle 14 in its initial shape, when the inner needle 14 is inserted into the needle tip protector 78 from the base end side, there is no need to push apart the pair of needle tip protection parts 84a, 84b, making the insertion of the inner needle 14 easier.

The inner needle 14 is inserted through the slit 76 of the valve body 70 and penetrates the valve body 70 in the needle axial direction. The outflow opening 28 of the inner needle 14 is located distal to the outer needle hub 42 and proximal to the tip of the outer needle 18, and opens in the inner cavity of the outer needle 18. At the axial position where the outflow opening 28 is formed, the outer needle 18 is spaced from the inner needle 14 on the outer periphery, so that the outflow opening 28 is not blocked by the outer needle 18 in close contact. On the proximal side of the outflow opening 28, the outer needle 18 is spaced from the inner needle 14 on the outer periphery. The reflux opening 30 of the inner needle 14 is located distal to the valve body 70 and opens to the first region 72 inside the outer needle hub 42. The reflux opening 30 is closer to the valve body 70 than to the tip of the outer needle hub 42. In this embodiment, the reflux opening 30 is located proximally of the tapered portion 48 of the outer needle hub 42.

In the indwelling needle assembly 10 thus constructed, the inner needle 14 and the outer needle 18 are first inserted into the patient's blood vessel. When the inner needle 14 is inserted into the blood vessel, blood flows into the lumen 21 of the inner needle 14 from the tip opening of the inner needle 14. The blood that flows into the lumen 21 flows through the lumen 21 toward the base end, but the flow is restricted and blocked by the narrowed portion 24, so that the blood flows out of the lumen 21 through the outflow opening 28 and flows into the lumen of the outer needle 18. The blood that has entered the lumen of the outer needle 18 flows between the inner needle 14 and the outer needle 18 toward the base end, and flows into the first region 72 inside the outer needle hub 42.

As blood flows into the first region 72, the air in the first region 72 is pushed out by the blood and discharged to the outside. That is, the air in the first region 72 flows into the lumen 21 of the inner needle 14 through the return opening 30, is discharged from the base end opening of the inner needle 14 to the inside of the cap member 38, and passes through the breathable filter 40 to be discharged to the outside. The return opening 30 allows not only air but also blood to pass through, and blood also flows into the inside of the cap member 38 through the lumen 21 of the inner needle 14, but the breathable filter 40 provided at the base end of the cap member 38 prevents blood from leaking to the outside and discharges air to the outside. In addition, when blood flows into the lumen 21 of the inner needle 14, it is expected that the air in the first region 72 will be drawn in and guided to the lumen 21.

In this way, the air in the first region 72 provided inside the outer needle hub 42 is discharged to the outside by introducing blood into the outer needle hub 42 through the outlet opening 28 and discharging air to the base end side through the return opening 30. In this way, priming, which fills the first region 72 with blood, is effectively performed, thereby preventing air from entering the indwelling needle 16 when it is used, which will be described later, and improving safety.

After the inner needle 14 and the outer needle 18 are inserted into the blood vessel, the inner needle 14 is withdrawn from the outer needle 18, and the retention needle 16 is retained in the blood vessel. As shown in FIG. 3, the inner needle 14 is withdrawn from the outer needle 18, and the tip opening of the outer needle 18 is opened, and the amount of blood flowing into the first region 72 of the outer needle hub 42 increases. However, since the first region 72 is filled with blood in advance and the air in the first region 72 is discharged, even if turbulence occurs due to an increase in the flow rate, for example, mixing of air into the blood is suppressed.

When the inner needle 14 is pulled out from the outer needle 18, the needle tip 22 moves between the pair of needle tip protection parts 84a, 84b of the needle tip protector 78. The locking projections 26, 26 of the inner needle 14 are then locked in the axial direction with the needle insertion part 80. When the inner needle 14 is further pulled out toward the base end, the needle tip protector 78 moves toward the base end together with the inner needle 14, and the needle tip protector 78 passes through the input part 64 of the plunger 60. When the needle tip protector 78 passes through the input part 64, the pair of needle tip protection parts 84a, 84b abut against the stepped part of the plunger 60, and the pair of needle tip protection parts 84a, 84b deform and approach each other, and are locked to each other. The needle tip protection parts 84a and 84b, which are close to each other, are positioned to cover and protect the tip side of the needle tip 22 of the inner needle 14, as shown in FIG. 3, and the needle tip protector 78 prevents the tip side of the needle tip 22 from being exposed.

In addition, the pair of needle tip protection parts 84a, 84b in the needle tip protector 78 may be configured to cover the needle tip 22 by deforming from an initial position separated from each other to a closed position where they approach each other by contacting the stepped portion of the plunger 60, and may, for example, prevent the pair of needle tip protection parts 84a, 84b elastically held in the initial position from elastically returning to the initial position by locking them in the closed position. Preferably, for example, the base end parts of the pair of needle tip protection parts 84a, 84b may be configured to have a curved cross-sectional shape or the like to have spring characteristics, so that at the boundary position between the initial position separated from each other and the close protective position, they are elastically deformed alternatively to the initial position and the protective position, and the shape is stably held in either the initial position or the protective position. However, in order to prevent the re-exposure of the needle tip due to intentional or unintentional spreading of the pair of needle tip protection parts 84a, 84b of the closed needle tip protector 78 when the inner needle 14 is pulled out, it is desirable to provide a locking mechanism or the like to prevent the pair of needle tip protection parts 84a, 84b from deforming in the direction away from each other even when the shape of the pair of needle tip protection parts 84a, 84b is maintained in the protective position.

The inner needle 14, whose needle tip 22 is protected by the needle tip protector 78, is pulled out toward the base end relative to the outer needle hub 42 and separated from the outer needle hub 42. Even when the needle tip protector 78 is separated from the outer needle hub 42, the needle tip protection parts 84a, 84b are held in a protective position close to each other, so that the needle tip 22 continues to be protected.

The indwelling needle 16 separated from the inner needle unit 12 is placed in a state in which the outer needle 18 is inserted into the patient's blood vessel. The placed indwelling needle 16 is connected to the base end of the outer needle hub 42, for example, with an infusion line, connector, syringe, etc. (not shown). The male luer of the connector or syringe connected to the outer needle hub 42 is inserted into the luer insertion portion 56 of the outer needle hub 42 and pressed against the base end of the input portion 64 of the plunger 60, so that an external force that moves the plunger 60 toward the tip side is applied to the input portion 64, and the plunger 60 is pushed toward the tip. Then, as the plunger 60 moves toward the tip side, the action portion 66 of the plunger 60 is pressed against the valve body 70. This causes the valve body 70 to elastically deform, pushing open the slit 76 in the valve body 70, and the patient's blood vessel is connected to the infusion line, syringe, etc. through the open slit 76, allowing infusion or administration of medication through the indwelling needle 16.

Figures 4 and 5 show a valve body 90 constituting an indwelling needle assembly according to a second embodiment of the present invention. The valve body 90 can be used, for example, in place of the valve body 70 in the indwelling needle assembly 10 of the first embodiment. In the following description, the same reference numerals are used in the figures to denote components and parts that are substantially the same as those in the previous embodiment, and description thereof will be omitted. In addition, parts of the indwelling needle assembly that are not shown in the figures are the same as those in the first embodiment.

The valve body 90 has a needle insertion hole 92 that penetrates the radial center part in the axial direction, which is the thickness direction. As shown in FIG. 5, the needle insertion hole 92 is composed of a needle arrangement part 94 corresponding to the inner needle 14 and a plurality of grooves 96 that open to the inner peripheral surface of the needle arrangement part 94. As a result, the needle insertion hole 92 has an inside dimension larger than the outer diameter dimension of the inner needle 14 at the part where the groove 96 is formed, and has an inside dimension approximately the same as the outer diameter dimension of the inner needle 14 at the part outside the groove 96 in the circumferential direction. The number of grooves 96 that constitute the needle insertion hole 92 and their circumferential arrangement are not particularly limited, but in this embodiment, eight grooves 96 are arranged at approximately equal intervals in the circumferential direction.

As shown in FIG. 5, the inner needle 14 is inserted into the needle insertion hole 92 of the valve body 90. When the inner needle 14 is inserted, the needle insertion hole 92 is narrowed by the inner needle 14, and an exhaust hole 98 that penetrates the valve body 90 in the axial direction is formed between the inner peripheral surface of the needle insertion hole 92 and the outer peripheral surface of the inner needle 14. The exhaust hole 98 is formed by extending in the axial direction between the inner peripheral surface of the valve body 90 and the outer peripheral surface of the inner needle 14, as the opening of the groove 96 is covered by the inner needle 14. The groove cross-sectional area of the groove 96 is sufficiently small compared to the hole cross-sectional area of the needle arrangement portion 94, and the hole cross-sectional area of the exhaust hole 98 is sufficiently small compared to the needle insertion hole 92. The hole shape and hole cross-sectional area of the exhaust hole 98 are set so that air is allowed to pass and blood passage is restricted by flow resistance. In this embodiment, the outer circumferential surface of the inner needle 14 contacts the inner circumferential surface of the valve body 90 on both circumferential sides of the exhaust hole 98, and the needle placement portion 94 is substantially blocked by the inner needle 14, but for example, the inner needle 14 and the valve body 90 may be separated from each other not only in the portion where the groove 96 is formed, but also in the portion circumferentially outside the groove 96.

According to an indwelling needle assembly including a valve body 90 structured according to this embodiment, a first region on the distal side of the valve body 90 in the outer needle hub and a second region on the proximal side of the valve body 90 in the outer needle hub are in communication with each other through an exhaust hole 98. Therefore, when the outer needle is inserted into a blood vessel and blood flows into the first region of the outer needle hub, air in the first region is exhausted through the exhaust hole 98 to the second region and is then exhausted to the outside from the proximal opening of the outer needle hub. This reduces the amount of air remaining in the first region, and prevents air from being mixed into a medicinal solution or the like when the medicinal solution or the like is administered into a blood vessel through the inside of the outer needle hub.

When the inner needle 14 is pulled out of the valve body 90, the entire needle insertion hole 92 formed in the center of the valve body 90 is opened, allowing blood to flow from the first region to the second region through the needle insertion hole 92. Therefore, if the male luer is connected to the outer needle hub before blood leaks out from the base end opening of the outer needle hub, blood leakage can be prevented. In particular, if the outer needle is bent so that the base end opening of the outer needle hub faces upward, blood leakage from the outer needle hub can be more effectively prevented.

In this embodiment, the needle insertion hole 92 has a groove 96 that opens to the inner peripheral surface, and the exhaust hole 98 is formed in the enlarged portion of the needle insertion hole 92 by the groove 96. However, for example, the needle insertion hole may be made larger in diameter than the outer diameter of the inner needle 14, and the inner needle 14 may be inserted into the needle insertion hole with a gap to form an exhaust hole by utilizing the gap. In this case, the inner needle 14 may be inserted into the center of the needle insertion hole, and the exhaust hole may be provided continuously around the entire circumference, or the inner needle 14 may be in contact with the inner peripheral surface of the needle insertion hole at a portion of the circumference, and the exhaust hole may be provided in a portion excluding the contact point between the inner needle and the inner peripheral surface of the needle insertion hole.

Figure 6 shows a valve body 100 constituting an indwelling needle assembly according to a third embodiment of the present invention. The valve body 100 can be used, for example, in place of the valve body 70 in the indwelling needle assembly 10 of the first embodiment. The valve body 100 is shaped like an elliptical plate, with the up-down direction in Figure 6 being the long axis direction. The valve body 100 has an opening 102 penetrating the central portion in the thickness direction. The opening 102 is an approximately elliptical hole that is flattened overall in the up-down direction, with the left-right direction being the long axis direction in the cross section of the hole. The opening 102 has a main opening 104 which is an elliptical hole, and groove-shaped sub-openings 106, 106 that open on the inner peripheral surface of the main opening 104 and extend in the thickness direction of the valve body 100.

The sub-opening 106 has a substantially semicircular cross section. Pairs of sub-openings 106, 106 are formed at corresponding positions in the up-down direction, and are arranged at positions where the openings of the pair of sub-openings 106, 106 are butted together due to elastic deformation of the valve body 100, which will be described later. In this embodiment, pairs of sub-openings 106, 106 are provided at three locations spaced apart from each other in the left-right direction in FIG. 6.

The valve body 100 is attached to the outer needle hub 42. The valve body 100 is an oval disk with its long axis extending in the vertical direction. By fitting into the inner peripheral surface of the cylindrical outer needle hub 42, it is significantly compressed in the vertical direction and is disposed inside the outer needle hub 42 in a state in which it is elastically deformed into a roughly circular shape, as shown in FIG. 7.

When the valve body 100 is attached to the outer needle hub 42, it is compressed in the vertical direction, and the opening width dimension of the main opening 104 of the opening 102 in the vertical direction is reduced. In this embodiment, in the valve body 100 after it is attached to the outer needle hub 42, the inner circumferential surfaces of the main opening 104 are in contact with each other in the vertical direction, and the main opening 104 is closed. In the valve body 100 of this embodiment, a slit extending linearly in the left-right direction is formed by utilizing the main opening 104 whose inner surfaces are in contact with each other in the vertical direction and closed.

By making the opening width dimension of the main opening 104 approximately 0 in the vertical direction, the opening edges of the pair of sub-openings 106, 106 in the vertical direction are butted against each other, and the sub-openings 106, 106 form an exhaust hole 108 with a substantially circular cross section. In this embodiment, three exhaust holes 108 are formed side by side in the left-right direction. The exhaust holes 108 have a cross-sectional area smaller than that of the opening 102, and the hole shape and cross-sectional area are set so as to allow the passage of air and restrict the passage of blood. In this embodiment, the central exhaust hole 108 is blocked by the inner needle when the inner needle is inserted, and is opened by pulling the inner needle out of the outer needle. However, the central exhaust hole 108 may be made larger in diameter than the outer diameter of the inner needle, for example, and may be narrowed by the insertion of the inner needle to form an exhaust hole on the outer peripheral surface of the inner needle.

According to the valve body 100 of this embodiment, air in a first region inside the outer needle hub 42, which is closer to the tip side than the valve body 100, is exhausted through the exhaust hole 108 to a second region, which is closer to the base end than the valve body 100. Therefore, air is less likely to remain in the first region, and the amount of air injected into the blood vessel together with the medicinal solution or the like can be reduced, improving safety.

6 and 7 show an example of an opening 102 having a main opening 104 provided in the middle portion without opening to the outer peripheral surface of the valve body 100, but the main opening may be, for example, an inverted V-shaped groove that opens to the outer peripheral surface on either the left or right side of the valve body 100. In this case, a sub-opening 106 is formed opening to the inner surface of the main opening, and the main opening is closed by compression accompanying attachment of the valve body 100 to the outer needle hub, thereby forming an exhaust hole 108 by the sub-opening 106.

Figure 8 shows a valve body 110 constituting an indwelling needle assembly according to a fourth embodiment of the present invention. The valve body 110 can be used, for example, in place of the valve body 70 in the indwelling needle assembly 10 of the first embodiment. The valve body 110 is elliptical plate-shaped, and the vertical direction in Figure 8 is the long axis direction. The valve body 110 has a pair of openings 112, 112 penetrating in the thickness direction. The openings 112 are substantially circular holes, and are provided on both sides in the vertical direction at the center in the horizontal direction. Note that in this embodiment, a slit 76 that extends linearly in the horizontal direction is illustrated, but the shape and size of the slit 76 are not particularly limited.

The valve body 110 is attached to the outer needle hub 42. The oval disk-shaped valve body 110, whose long axis is in the vertical direction, is fitted into the inner peripheral surface of the cylindrical outer needle hub 42, and is significantly compressed in the vertical direction. As shown in FIG. 9, the valve body 110 is disposed inside the outer needle hub 42 in a state in which it is elastically deformed into a substantially circular shape.

The valve body 110 is compressed in the vertical direction by being attached to the outer needle hub 42, and the opening width dimension in the vertical direction of the openings 112, 112 is reduced. In the valve body 110 attached to the outer needle hub 42 shown in FIG. 9, the inner circumferential surfaces of the openings 112, 112 are separated in the vertical direction and are maintained in an open state. Therefore, in the valve body 110 attached to the outer needle hub 42, the vertical width dimension of the opening 112 is reduced, the opening 112 has a flat opening shape in the vertical direction, and the hole cross-sectional area of the opening 112 is reduced. In this way, the opening 112 that is reduced and deformed due to the elastic deformation caused by the attachment of the valve body 110 to the outer needle hub 42 forms an exhaust hole 114 that penetrates the valve body 110. In the valve body 110 attached to the outer needle hub 42, the hole cross-sectional area and hole shape of the exhaust hole 114 are set so as to allow the passage of air and restrict the passage of blood.

According to the valve body 110 of this embodiment, air in a first region inside the outer needle hub 42, which is closer to the tip side than the valve body 110, is exhausted through the exhaust hole 114 to a second region, which is closer to the base end than the valve body 110. Therefore, air is less likely to remain in the first region, and the amount of air injected into the blood vessel together with the medicinal solution, etc., can be reduced, improving safety.

10 and 11 show a valve body 120 constituting an indwelling needle assembly according to a fifth embodiment of the present invention. The valve body 120 can be used, for example, in place of the valve body 70 in the indwelling needle assembly 10 of the first embodiment. The valve body 120 is composed of a first valve member 122 and a second valve member 124 that are overlapped in the axial direction.

The first valve member 122 is an elastic body having a generally circular disk shape. The first valve member 122 has a pair of upper and lower first through holes 126, 126. The first through holes 126 are generally circular holes that penetrate the first valve member 122 in the thickness direction. The first valve member 122 has a linear first slit 128 that extends in the left-right direction in the central portion in the up-down direction.

The second valve member 124 is an elastic body having a substantially circular plate shape. The second valve member 124 has a circular second through hole 130 that penetrates the center in the thickness direction. The second through hole 130 may be formed in a different shape and size from the first through hole 126, but may be formed in the same shape and size as the first through hole 126. In this embodiment, the first through hole 126 and the second through hole 130 are the smallest holes that can be formed when molding the first valve member 122 and the second valve member 124, and are formed in substantially the same shape and size.

A narrowing groove 132 is formed in the second valve member 124. The narrowing groove 132 extends in the vertical direction with a groove cross-sectional area smaller than the hole cross-sectional area of the second through hole 130. The narrowing groove 132 opens on one surface of the second valve member 124 and extends in the vertical direction. The narrowing groove 132 passes through the center of the second valve member 124, and the second through hole 130 that penetrates the center of the second valve member 124 opens into the narrowing groove 132. In other words, the narrowing groove 132 is formed on one surface of the second valve member 124 so as to extend linearly from the opening of the second through hole 130 to both sides in the radial direction.

As shown in FIG. 11, the second valve member 124 is formed with a second slit 134. The second slit 134 is a straight line that passes through the center of the second valve member 124 and extends in the vertical direction. One opening of the second slit 134 is located within the narrowing groove 132 on one surface of the second valve member 124.

The first valve member 122 and the second valve member 124 are overlapped in the thickness direction to form the valve body 120. The first valve member 122 and the second valve member 124 are desirably positioned relative to each other, and may be fixed to each other, or may be positioned relative to each other by a separate member such as an outer needle hub (not shown).

In the valve body 120, the first through holes 126, 126 and the second through hole 130 are provided at positions spaced apart from each other when viewed in the axial direction, and are arranged so as not to be lined up in series in the axial direction (left-right direction in FIG. 11). In this embodiment, the first through holes 126, 126 are arranged at positions spaced apart above and below the second through hole 130, which is located in the center.

The opening of the narrowing groove 132 of the second valve member 124 is covered by the first valve member 122. As a result, a narrowing passage 136 extending linearly in the vertical direction is formed between the overlapping surfaces of the first valve member 122 and the second valve member 124. The narrowing groove 132 extends from the first through holes 126, 126 to the second through hole 130, and the narrowing passage 136 is connected to the first through holes 126, 126 at both ends in the vertical direction and to the second through hole 130 at the center in the vertical direction. The first through holes 126, 126, the narrowing passage 136, and the second through hole 130 form an exhaust hole 138 that penetrates the valve body 120. The exhaust hole 138 has a smaller flow passage cross-sectional area at the middle portion formed by the narrowed flow passage 136 compared to both ends formed by the first through holes 126, 126 and the second through hole 130, and the flow resistance of the exhaust hole 138 is set mainly by the narrowed flow passage 136. The flow resistance of the exhaust hole 138 is set to allow the passage of air and restrict the passage of blood.

According to the valve body 120 of this embodiment, a narrowed flow path 136 formed by a narrowed groove 132 is provided between the first valve member 122 and the second valve member 124, and the exhaust hole 138 is configured to include the narrowed flow path 136. This makes it possible to set a flow resistance in the exhaust hole 138 that cannot be achieved by a simple through hole such as the first through hole 126 or the second through hole 130, and makes it possible to exhaust air from within the outer needle hub while suppressing blood leakage.

The shape, number, arrangement, etc. of the first through hole 126 and the second through hole 130 are not particularly limited and may be changed as appropriate. The narrowing groove 132 is provided across the first through hole 126 and the second through hole 130, and when the first valve member 122 and the second valve member 124 are combined to form the valve body 120, it is sufficient to form a narrowing flow path 136 connecting the first through hole 126 and the second through hole 130, and the arrangement and shape of the narrowing groove 132 may be changed. In addition, for example, when there are multiple first through holes 126 and multiple second through holes 130, it is also possible to provide multiple narrowing grooves 132, and in that case, multiple independent exhaust holes 138 may be formed. In addition, three or more valve members may be stacked to form a valve body, and in that case, the narrowing groove may be formed on only one side of one valve member, the narrowing groove may be formed on both sides of one valve member, or the narrowing groove may be formed on one or both sides of two or more valve members.

The valve bodies 90, 100, 110, and 120 shown in the second to fifth embodiments may be used in combination with the inner needle 14 having an exhaust structure with the outlet opening 28 and the return opening 30 shown in the first embodiment, or may be used in combination with a conventional inner needle that does not have an exhaust structure.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific description. For example, in the above embodiment, an indwelling needle assembly equipped with a needle tip protector is exemplified, but a needle tip protector is not essential. Furthermore, when a needle tip protector is provided, the structure of the needle tip protector is not particularly limited, and various structures including conventionally known structures can be adopted.

The specific shape of the plunger 60 shown in the above embodiment and the structure in which the needle tip protector is housed in the plunger 60 are not essential. For example, the plunger may be in a tapered cylindrical shape, and the needle tip protector may be housed in the outer needle hub proximal to the plunger.

As shown in the first embodiment, when the inner needle 14 is provided with an outflow opening 28 and a return opening 30, it is desirable to provide a narrowing portion 24 between the outflow opening 28 and the return opening 30, but the narrowing portion 24 is not essential. The narrowing portion 24 does not necessarily have to be a crushed portion formed at the same time as the locking protrusions 26, 26, and the locking protrusions 26, 26 may be provided separately from the narrowing portion 24, or if there is no narrowing portion 24, only the locking protrusions 26, 26 can be provided. Also, for example, an inner needle having a structure in which the narrowing portion 24 is provided and the locking protrusions 26, 26 are not provided can be used.

10 Indwelling needle assembly (first embodiment)
12 Inner needle unit 14 Inner needle 16 Indwelling needle 18 Outer needle 20 Inner needle hub 21 Inner cavity 22 Needle tip 24 Narrowed portion 26 Locking projection (protector locking portion)
28 Outflow opening 30 Reflux opening 32 Hub body 34 Inner needle holding portion 36 Flange-shaped portion 38 Cap member 40 Breathable filter 42 Outer needle hub 44 Needle fixing member 46 Luer connecting member 48 Tapered portion 50 Engagement hole 54 Hub connecting portion 56 Luer insertion portion 58 Engagement claw 60 Pusher 62 Protector accommodating portion 64 Input portion 66 Action portion 70 Valve body 72 First region 74 Second region 76 Slit 78 Needle tip protector 80 Needle insertion portion 82 Circular hole 84 Needle tip protection portion 90 Valve body (second embodiment)
92 Needle insertion hole 94 Needle placement portion 96 Groove 98 Exhaust hole 100 Valve body (third embodiment)
102 Opening 104 Main opening 106 Sub-opening 108 Exhaust hole 110 Valve body (fourth embodiment)
112 Opening 114 Exhaust hole 120 Valve body (Fifth embodiment)
122 First valve member 124 Second valve member 126 First through hole 128 First slit 130 Second through hole 132 Narrowed groove 134 Second slit 136 Narrowed flow passage 138 Exhaust hole

Claims (6)

An indwelling needle assembly in which a hollow inner needle having an inner needle hub on a base end side is inserted removably into an outer needle having an outer needle hub on a base end side, and a valve body for switching between communication and blocking of the outer needle hub is disposed inside the outer needle hub,
an outlet opening and a reflux opening are formed through a peripheral wall of the inner needle;
the reflux opening provided proximally relative to the outflow opening is initially open inside the outer needle hub distal to the valve body ,
a distance between the reflux opening and the valve body is closer than a distance between the reflux opening and the distal end of the outer needle hub;
The blood flowing into the inner cavity of the inner needle due to puncture is discharged into the outer needle hub through the outlet opening and is also discharged into the inner cavity of the inner needle through the return opening.
The inner needle hub is provided with a breathable filter,
The indwelling needle assembly in which air pushed into the inner needle hub by blood flowing in from the lumen of the inner needle passes through the breathable filter and is discharged to the outside . a crushed portion is provided in which the inner needle is crushed between the outflow opening and the return opening in an axial direction,
2. The indwelling needle assembly according to claim 1 , wherein a protector engagement portion that engages with a needle tip protector that protects the tip of the inner needle when the inner needle is pulled out from the outer needle is provided on the inner needle by radial expansion that accompanies crushing of the inner needle at the crushed portion . the valve body is formed with a needle insertion hole through which the inner needle is inserted,
3. The indwelling needle assembly according to claim 1, wherein an exhaust hole penetrating the valve body is formed between the inner needle and the needle insertion hole when the inner needle is inserted into the needle insertion hole. an opening is formed in the valve body, the opening penetrating in a needle axis direction of the inner needle,
the valve body is disposed inside the outer needle hub in a state where it is radially compressed by the outer needle hub,
3. The indwelling needle assembly according to claim 1, wherein the opening is reduced by radial compression of the valve body, and an exhaust hole penetrating the valve body is formed by the reduced opening. the opening portion includes a main opening and a groove-shaped sub-opening that opens on an inner circumferential surface of the main opening and penetrates the valve body in a needle axis direction of the inner needle,
5. The indwelling needle assembly according to claim 4, wherein the main opening is closed by radial compression of the valve body, and the sub-opening constitutes the exhaust hole. the valve body includes a first valve member and a second valve member which are overlapped in a needle axis direction of the inner needle,
a first through hole is formed in the first valve member and a second through hole is formed in the second valve member, the first through hole and the second through hole being spaced apart from each other when viewed in the axial direction;
a narrowed groove is formed in at least one of the mating surfaces of the first valve member and the second valve member, the narrowed groove extending across the first through hole and the second through hole;
The first through hole, the second through hole, and the narrowed groove form an exhaust hole penetrating the valve body,
3. The indwelling needle assembly according to claim 1, wherein a cross-sectional area of the narrowed groove is smaller than cross-sectional areas of the first through hole and the second through hole.