WO2018092823A1

WO2018092823A1 - Cannula

Info

Publication number: WO2018092823A1
Application number: PCT/JP2017/041193
Authority: WO
Inventors: 貴新井; 直朗安村
Original assignee: ニプロ株式会社
Priority date: 2016-11-17
Filing date: 2017-11-16
Publication date: 2018-05-24
Also published as: BR112019007961A2; JP6788792B2; JP2018079154A

Abstract

Provided is a cannula having a novel structure which can suppress a discharging speed of blood while ensuring a flow rate of the discharged blood. This cannula 10 is provided with: a protrusion part 56 which is provided on the inner peripheral side of a peripheral wall 22 of a tip portion in which a plurality of discharge ports 64 are provided and which protrudes from a tip closing part 50 which closes an internal flow passage 16 on a tip surface; and a direction change part 58 which is provided on the outer peripheral side of the protrusion part 56 at the tip closing part 50 and in which the inclined angle of the outer peripheral surface 59 of the protrusion part 56 is decreased. In pillar portions 44, which longitudinally extend between the plurality of discharge ports 64 neighboring each other in the circumferential direction, end portions of at least the tip sides serve as opening defining parts 48, 78 which define the opening widths of each of the corresponding discharge ports 64, thereby allowing the blood flow that is guided by the direction change part 58 and discharged to be continuous in the circumferential direction.

Description

Cannula

The present invention relates to a cannula that is inserted into a blood vessel and allows blood to flow in an internal flow path.

Conventionally, a cannula that is inserted into a blood vessel so that blood flows in an internal flow path is known. For example, Japanese Patent Laid-Open No. 8-196624 (Patent Document 1) proposes a cannula that is inserted into the aorta during cardiac surgery. That is, in Patent Document 1, blood taken out of the body during cardiac surgery is returned to the patient's aorta via a cannula inserted into the aorta and circulates in the patient's body.

By the way, in such an aortic cannula, the amount of blood flowing in the cannula is very large, and the blood discharged from the cannula may hit the inner wall of the blood vessel as a jet flow. In such a case, the blood ejected vigorously may damage the blood vessel. For example, a blood clot attached to the blood vessel may be peeled off and flowed downstream to cause embolism.

Therefore, in the cannula of Patent Document 1, the tip of the internal flow path is closed and a plurality of discharge ports are provided in the peripheral wall of the tip portion, and blood is discharged in a dispersed manner through the plurality of discharge ports, thereby allowing the cannula to be removed. The flow rate of the discharged blood is reduced.

However, in the cannula described in Patent Document 1, as shown in FIGS. 9 and 10 of Patent Document 1, blood is only discharged from each of a plurality of discharge ports. Therefore, it is difficult to sufficiently reduce the flow rate while ensuring the flow rate of the discharged blood, and there is a possibility that damage to the blood vessels cannot be avoided sufficiently.

JP-A-8-196624

The present invention has been made in the background of the above-described circumstances, and a solution to the problem is to provide a cannula having a novel structure capable of suppressing the discharge speed while ensuring the flow rate of the discharged blood. It is in.

Hereinafter, embodiments of the present invention made to solve such problems will be described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

In the first aspect of the present invention, the internal flow path extending from the proximal end side toward the distal end side is closed at the distal end surface, and a plurality of discharge ports are provided apart from each other in the circumferential direction on the peripheral wall of the distal end portion. In the provided cannula, a protruding portion that protrudes from a distal end closing portion that closes the internal flow path at the distal end surface is provided on the inner peripheral side of the peripheral wall of the distal end portion provided with the plurality of discharge ports. A plurality of discharge ports adjacent to each other in the circumferential direction are formed on the outer peripheral side portion of the protruding portion in the tip closing portion, while turning portions having a small inclination angle of the outer peripheral surface of the protruding portion are formed. At least the end of the columnar portion made of the peripheral wall extending in the lengthwise direction between the two ends is defined by the opening width of each of the discharge ports, thereby circulating the blood flow discharged and discharged by the turning portion. Apertures that are continuous with each other in direction And it is characterized in that it is a part.

According to the cannula configured according to this aspect, the protrusion is provided on the inner peripheral side of the plurality of discharge ports, and the inclination angle of the outer peripheral surface of the protrusion is small in the outer peripheral side portion of the protrusion. Since the directed turning portion is formed, the blood flow direction is changed by the blood hitting the turning portion. Therefore, the blood flowing in the internal flow path can be more reliably directed to the outer peripheral side, and the blood can be discharged so as to spread to the outer peripheral side through the discharge port. Moreover, the blood flows guided by the turning portion and discharged from the discharge port are continuously connected to each other in the circumferential direction by the opening defining portion of the discharge port. And, by the synergistic action of these turning portion and opening defining portion, the blood flow discharged from the tip of the cannula is discharged in a hollow tubular or umbrella-like flow manner that spreads in the discharge direction as a whole. It will be. Thereby, it is possible to efficiently suppress the speed while securing the flow rate of blood discharge, and damage to the blood vessels can be reduced.

According to a second aspect of the present invention, in the cannula according to the first aspect, as the opening defining portion, a tapered portion having a circumferential width gradually narrowing at least at an end portion on the distal end side of the columnar portion is provided. Accordingly, the circumferential width of each discharge port is gradually increased toward the tip.

According to the cannula having the structure according to this aspect, the columnar portion extending in the length direction is provided between the circumferential directions of the discharge ports, and the columnar portion has a circumferential width at least at the end on the distal end side. Since the taper-shaped part which becomes gradually narrow is provided, the circumferential direction width | variety of each discharge port is gradually enlarged toward the front-end | tip. Therefore, the blood discharged from the discharge ports adjacent in the circumferential direction can be more efficiently connected to each other by the synergistic action of the turning portion and the tapered portion.

According to a third aspect of the present invention, in the cannula according to the first aspect, as the opening defining portion, a narrow width in which a circumferential width dimension at least at an end portion of the columnar portion is 0.6 mm or less. The part is provided.

According to the cannula having the structure according to this aspect, the columnar portion extending in the length direction is provided between the circumferential directions of the discharge ports, and the circumferential width dimension at the end portion on the distal end side of the columnar portion is 0. .6 mm or less and narrowed. That is, the separation distance between the discharge ports adjacent in the circumferential direction can be reduced, and the blood discharged from the discharge ports adjacent in the circumferential direction can be reduced by the synergistic action of the turning portion and the narrow width portion. They can be connected more efficiently.

According to a fourth aspect of the present invention, in the cannula according to any one of the first to third aspects, the columnar portion is provided with a protruding rib that protrudes in a tapered direction toward the inner peripheral side and extends in the length direction. It is what has been.

According to the cannula having a structure according to this aspect, the projecting rib is provided on the inner peripheral side of the columnar portion, so that the strength in the columnar portion is sufficiently ensured. In particular, since such protruding ribs are formed to extend in the length direction in a cross-sectional shape that tapers toward the inner peripheral side, there is also a possibility that the flow of blood flowing in the internal flow path may be adversely affected. Can be reduced.

A fifth aspect of the present invention is the cannula according to the fourth aspect, wherein the protruding rib is connected to the outer peripheral portion of the protruding portion in the distal end closing portion at the distal end side end portion of the columnar portion. It is what has been.

According to the cannula having the structure according to this aspect, since the tip side end portion of the protruding rib is connected to the outer peripheral portion of the protruding portion in the tip closing portion, for example, when the tapered portion is provided in the columnar portion Therefore, it is possible to more reliably improve the strength of the end portion on the front end side of the columnar portion which tends to be weak.

According to a sixth aspect of the present invention, in the cannula according to any one of the first to fifth aspects, the columnar portion extends with a constant circumferential width over a predetermined length on the proximal end side.

According to the cannula having the structure according to this aspect, the columnar portion has a constant circumferential width dimension over a predetermined length on the proximal end side, so that the strength in the columnar portion is more stably secured. obtain.

According to a seventh aspect of the present invention, in the cannula according to any one of the first to sixth aspects, the curved connecting surface smoothly connected to the outer peripheral surface of the projecting portion is provided on the inner peripheral edge portion of the deflecting portion. Is provided.

According to the cannula having the structure according to the present aspect, the outer peripheral surface of the protruding portion and the turning portion are smoothly connected by the curved connecting surface, so that the discharged blood is guided more smoothly.

According to an eighth aspect of the present invention, in the cannula according to any one of the first to seventh aspects, the distal end portion has a curved shape, and the discharge port located on the outer peripheral side of the curved shape includes Compared to the discharge port located on the inner peripheral side of the curved shape, the length is made smaller.

According to the cannula having the structure according to this aspect, since the tip portion has a curved shape, the cannula can be inserted into the blood vessel more easily. In addition, the difference in blood flow rate discharged from each discharge port due to the curved tip of the cannula can be reduced by the relative setting of the length of the discharge port, The discharge in a continuous tubular flow mode can be realized more stably.

According to the cannula having a structure according to the present invention, it is possible to suppress the discharge speed while ensuring the flow rate of the discharged blood.

The perspective view which shows the front-end | tip part in the cannula as the 1st Embodiment of this invention. The front view of the front-end | tip part in the cannula shown by FIG. The front view which expands and shows the principal part in FIG. The top view of the front-end | tip part in the cannula shown by FIG. FIG. 2 is a bottom view of the distal end portion of the cannula shown in FIG. 1. The longitudinal cross-sectional view of the front-end | tip part in the cannula shown by FIG. The longitudinal cross-sectional view which expands and shows the principal part in FIG. VIII-VIII sectional drawing in FIG. Explanatory drawing for demonstrating the state which discharged the fluid using the cannula shown by FIG. 1 with a side view. Explanatory drawing for demonstrating the state which discharged the fluid using the cannula shown by FIG. 1 by the back view different from FIG. The perspective view which shows the front-end | tip part in the cannula as the 2nd Embodiment of this invention. The front view which expands and shows the principal part in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, FIGS. 1 to 8 show an aorta cannula 10 as a first embodiment of the present invention. The cannula 10 has a tubular shape as a whole, and is configured by attaching a distal tip 14 to a distal end portion of a cannula main body 12. The distal tip 14, which is the distal end portion of the cannula 10, is inserted into the aorta, so that blood that has flowed in from the proximal end side of the cannula 10 passes through the internal channel 16 formed in the cannula 10. It is designed to be discharged. In the following description, the length direction is a direction in which the central axis of the cannula 10 extends, and is a direction from the right to the left in FIG. 2 and then curved to the lower left in FIG. It is. Further, the distal side refers to the left side in FIG. 2 where the distal tip 14 is attached to the cannula body 12, while the proximal side refers to the flow of blood into the cannula body 12. The right side inside.

More specifically, the cannula body 12 has a flexible tube shape, and is made of polyamide, polyvinyl chloride, polyurethane, polyimide, polyethylene, polyethylene elastomer, polypropylene, polytetrafluoroethylene, polyetherketone, polyfluoride. It is made of a soft synthetic resin such as vinylidene. The cannula body 12 includes a peripheral wall 18, and an inner hole 20 penetrating in the length direction is formed on the inner peripheral side of the peripheral wall 18. As the cannula body, for example, a braided wire made of metal or the like, a coil spring such as a circular cross-section spring or a square spring, etc. may be embedded inside the peripheral wall 18 to be reinforced.

A tip tip 14 is attached to the tip end side of the cannula main body 12. The tip chip 14 has a generally cylindrical shape as a whole, and is formed of a hard synthetic resin such as polypropylene, polycarbonate, polyester, polyvinyl chloride, or polyurethane. That is, the tip 14 has a peripheral wall 22, and an inner hole 24 extending in the length direction is formed on the inner peripheral side of the peripheral wall 22. The inner hole 20 of the cannula body 12 and the inner hole 24 of the distal tip 14 are communicated with each other, and the inner flow path 16 of the cannula 10 is constituted by these

inner holes

20 and 24.

In the present embodiment, the shape of the distal tip 14 is different in the length direction, and is composed of a distal end portion 26 and a proximal end portion 28.

That is, the proximal end side portion 28 of the distal tip 14 has a substantially tapered cylindrical shape extending substantially linearly, and has a proximal end peripheral wall portion 30 having a substantially constant thickness, and the proximal end peripheral wall portion 30. The base end side inner hole 32 formed in the inner peripheral side is provided. The inner peripheral surface and the outer peripheral surface of the base end side peripheral wall portion 30 are configured such that the inner diameter dimension and the outer diameter dimension become gradually smaller toward the distal end side. In addition, since the cannula 10 of the present embodiment is for the aorta, it is thicker than other blood vessel cannulas. The specific dimension is set according to the application and is not limited. For example, the inner diameter φ _A (see FIG. 6) at the base end portion of the base end side peripheral wall portion 30 is about 3 to 19 mm. The outer diameter dimension φ _B (see FIG. 6) at the base end portion of the base end side peripheral wall portion 30 is about 4 to 20 mm.

Further, the base end side peripheral wall portion 30 having a substantially tapered cylindrical shape is provided with a connecting tube portion 34 protruding to the base end side. The connecting cylinder part 34 has an inner diameter dimension substantially equal to an inner diameter dimension at the proximal end of the proximal end side peripheral wall part 30 (maximum inner diameter dimension of the proximal end side peripheral wall part 30). On the other hand, as the outer diameter dimension of the connecting tube portion 34 becomes closer to the base end side than the outer diameter dimension at the base end of the base end side peripheral wall portion 30 (the maximum outer diameter dimension of the base end side peripheral wall portion 30), Has been made smaller. The tip portion of the cannula body 12 is extrapolated with respect to the connecting tube portion 34, and is fixed by welding, adhesion, caulking, or the like as necessary, whereby the cannula body 12 and the tip tip 14 are connected to each other. It has come to be.

On the other hand, the distal end portion 26 of the distal tip 14 has a curved cylindrical shape that curves downward in FIG. 2, and includes a distal end side peripheral wall portion 36 having a substantially constant thickness dimension, and the distal end side peripheral wall portion 36. A tip side inner hole 38 formed on the inner peripheral side is provided. Therefore, the peripheral wall 22 of the tip tip 14 is configured including the tip side peripheral wall portion 36 and the base end side peripheral wall portion 30, and the tip tip including the tip side inner hole 38 and the base end side inner hole 32. 14 inner holes 24 are formed.

The inner diameter dimension and the outer diameter dimension of the distal end side peripheral wall portion 36 are substantially constant in the length direction, and the inner diameter dimension of the distal end side peripheral wall portion 36 is the inner diameter dimension (base end) at the distal end of the proximal end side peripheral wall portion 30. It is substantially equal to the minimum inner diameter dimension of the side peripheral wall portion 30. Thereby, the inner peripheral surface (front end side inner hole 38) of the distal end side peripheral wall portion 36 and the inner peripheral surface (base end side inner hole 32) of the proximal end side peripheral wall portion 30 are smoothly connected to each other. On the other hand, the outer diameter dimension of the distal end side peripheral wall portion 36 is smaller than the outer diameter dimension at the distal end of the proximal end side peripheral wall portion 30 (the minimum outer diameter dimension of the proximal end peripheral wall portion 30). In addition, since the cannula 10 of the present embodiment is for the aorta, it is thicker than other blood vessel cannulas. The specific dimension is set according to the application and is not limited. For example, the inner diameter dimension φ _C (see FIG. 6) of the distal end side peripheral wall portion 36 is approximately 1 to 14 mm, while the distal end side peripheral wall is The outer diameter dimension φ _D (see FIG. 6) at the base end portion of the portion 36 is approximately 2 to 15 mm.

In this embodiment, the outer peripheral surface of the distal end side peripheral wall portion 36 and the outer peripheral surface of the proximal end side peripheral wall portion 30 are connected by a locking projection 40 that protrudes to the outer peripheral side. The locking projection 40 has a substantially semicircular longitudinal section and has a substantially annular shape extending continuously over substantially the entire circumference in the circumferential direction. The maximum outer diameter of the locking projection 40 is The outer diameter of the proximal end peripheral wall 30 is larger than the outer diameter. The outer peripheral surface of the locking protrusion 40 and the outer peripheral surface of the distal end side peripheral wall portion 36 are connected with a smooth curved surface.

A plurality of notches 42 that open to the distal end side are formed at the distal end of the distal end side peripheral wall portion 36. In the present embodiment, four notches 42, 42, 42, 42 are provided at substantially equal intervals in the circumferential direction, and the circumferential width dimensions of the respective notches 42 are substantially equal. On the other hand, the length dimension of the two notches 42 and 42 among these notches 42 is different from the length dimension of the remaining two notches 42 and 42. That is, in the distal end side peripheral wall portion 36, the

upper notches

42a and 42a in FIG. 2 positioned on the outer peripheral side of the curved shape are positioned on the inner peripheral side of the curved shape, and the lower notch 42b in FIG. , 42b, the length is made smaller.

By forming the

notches

42a, 42a, 42b, and 42b as described above, a columnar portion 44 that is configured by the distal end side peripheral wall portion 36 and extends in the length direction between the notches 42 and 42 that are adjacent in the circumferential direction. , 44, 44, 44 are formed.

Each

notch

42a, 42a, 42b, 42b is formed with a substantially constant circumferential width dimension from the base end portion over a predetermined length, while the front end side opening portion faces the front end side. It is gradually expanding. That is, the

columnar portions

44, 44, 44, 44 formed between the notches 42, 42 adjacent in the circumferential direction have a substantially constant circumferential width dimension over a predetermined length dimension from the base end side.

Equivalent width portions

46, 46, 46, 46 are formed. On the other hand, tapered

portions

48, 48, 48, 48 are formed at the tips of the

columnar portions

44, 44, 44, 44 that gradually decrease in the circumferential width dimension toward the tip side. Therefore, in this embodiment, by providing the

tapered portions

48, 48, 48, 48 at the end portions on the front end side of the

columnar portions

44, 44, 44, 44, the circumferential width dimension thereof is narrowed and the openings are opened. The defining part is configured.

The circumferential width dimension of the

columnar portions

44, 44, 44, 44 is not limited in any way, but the circumferential width dimension (tapered

portions

48, 48 at the tips of the

columnar portions

44, 44, 44, 44 is not limited. , 48, 48 is preferably 0.6 mm or less, more preferably 0.4 mm or less. In this embodiment, the minimum circumferential width dimension w) (see FIG. 3) is approximately 0. 4 mm. That is, by setting the circumferential width w at the tip of the columnar portion 44 to 0.6 mm or less, as will be described later, the fluid discharged from the discharge port 64 can be stably made into an umbrella shape or a tube shape.

Further, projecting

ribs

49, 49, 49, 49 are formed on the inner peripheral surfaces of the

columnar portions

44, 44, 44, 44, respectively, having a predetermined length and projecting toward the inner peripheral side. . In the present embodiment, the protruding

ribs

49, 49, 49, 49 are substantially the same shape and have substantially the same length, and each has a tapered cross section. The protruding

ribs

49, 49, 49, 49 reinforce the

columnar portions

44, 44, 44, 44 that are provided in the tapered

portions

48, 48, 48, 48 to reduce the circumferential width dimension, In the present embodiment, the protruding

ribs

49, 49, 49, 49 extend to the

equal width portions

46, 46, 46, 46 of the

columnar portions

44, 44, 44, 44. The protruding

ribs

49, 49, 49, 49 are formed so as to extend substantially over the entire length of the

columnar portions

44, 44, 44, 44 or further to the base end side than the

columnar portions

44, 44, 44, 44. Has been. In the present embodiment, the protruding

ribs

49, 49, 49, 49 have a substantially triangular cross section, and the corners are rounded.

The front end side opening portion of the front end side peripheral wall portion 36 having such a structure is closed by a front end closing portion 50. The distal end closing portion 50 is formed integrally with the distal end side peripheral wall portion 36 or the like, or is fixed after being formed separately from the distal end side peripheral wall portion 36 or the like. The distal end closing portion 50 has a cylindrical block shape as a whole, and the outer diameter dimension thereof is substantially equal to the outer diameter dimension of the distal end side peripheral wall portion 36. Further, the distal end side end surface 52 and the proximal end side end surface 54 of the distal end closing portion 50 have different inclination angles, and the proximal end side surface 54 of the distal end closing portion 50 is connected to the distal end side of the distal end side peripheral wall portion 36. While extending substantially perpendicular to the opening, the distal end side end surface 52 of the distal end closing portion 50 expands with a predetermined inclination angle with respect to the proximal end side end surface 54.

In the present embodiment, in the distal end closing portion 50, the length dimension on the upper side in FIG. 2 that is the outer peripheral side of the curved shape of the distal end side peripheral wall portion 36 is the inner peripheral side of the curved shape of the distal end side peripheral wall portion 36. It is made shorter than the length dimension of the lower side in FIG. In addition, this front-end | tip closing part 50 is made into the rounded chamfering shape which rounded the corner | angular part of the outer periphery of the most advanced surface. As described above, the distal end side surface 52 of the distal end closing portion 50 has a predetermined inclination angle with respect to the proximal end surface 54, whereby the distal end of the cannula 10 can be easily inserted into the aorta.

Further, a tapered projecting portion 56 projects from the proximal end surface 54 of the distal end closing portion 50, and the projecting portion 56 projects from a substantially central portion of the proximal end surface 54 in this embodiment. Furthermore, the protrusion 56 of the present embodiment has a substantially conical shape, and the central axis of the protrusion 56 is coaxially or slightly inclined with respect to the central axis of the proximal end surface 54 of the distal end closing part 50, That is, it protrudes in a direction substantially orthogonal to the proximal end surface 54 or substantially coaxial with the central axis of the distal peripheral wall portion 36.

In addition, the protrusion front end used as the top part of this protrusion part 56 may be a sharp shape, and may be rounded. In the longitudinal section shown in FIG. 7, the central angle α of the protrusion 56 corresponding to the apex angle of the cone is preferably 30 to 50 degrees. That is, when the central angle α is smaller than 30 degrees, the protruding portion has an excessively sharp shape, and the action of changing the direction of blood flow to the outer peripheral side may be reduced. On the other hand, if the central angle α is larger than 50 degrees, the inclination angle of the protrusion with respect to the blood flow direction becomes too large, and there is a concern that it is difficult to realize a smooth blood flow. The protrusion height t of the protrusion 56 is preferably 5 mm to 10 mm. That is, if the protrusion height dimension t is smaller than 5 mm, the action of changing the direction of blood flow to the outer peripheral side may be reduced, or a smooth blood flow may not be realized. On the other hand, when the protruding height dimension t is larger than 10 mm, the protruding portion 56 becomes longer than necessary, and the flow path may be narrowed between the distal end side peripheral wall portion 36 and the protruding portion 56.

The maximum outer diameter dimension of the protruding portion 56 (the outer diameter dimension of the protruding proximal end of the protruding portion 56) is smaller than the outer diameter dimension of the proximal end surface 54 of the distal end closing portion 50. From the outermost edge portion of the proximal end surface 54 to the projecting proximal end of the projecting portion 56, the outer diameter dimension gradually decreases toward the distal end side in the projecting direction of the projecting portion 56. In the present embodiment, a predetermined radial width dimension r on the outer peripheral side of the protruding portion 56 (see FIG. 7) between the length directions of the proximal end surface 54 of the distal end closing portion 50 and the protruding proximal end of the protruding portion 56. An annular step surface 58 is formed.

And, by providing the stepped surface 58 on the outer peripheral side portion of the protruding portion 56, the inclination angle of the outer peripheral surface 59 of the protruding portion 56 is different. That is, the inclination angle of the stepped surface 58 with respect to the base end side end surface 54 with respect to the inclination angle β (see FIG. 7) with respect to the base end side end surface 54 of the outer peripheral surface 59 on the protruding tip side with respect to the stepped surface 58 in the protruding portion 56. γ (see FIG. 7) is reduced (γ <β), and in the present embodiment, γ is approximately 0 degrees (γ≈0). Therefore, in this embodiment, the turning portion that reduces the inclination angle of the outer peripheral surface 59 of the protrusion 56 is formed by the step surface 58 in the outer peripheral side portion of the protrusion 56.

The radial width dimension r of the step surface 58 is preferably 0 <r ≦ 1 mm. That is, when the radial width dimension r is set to 0, the action of changing the direction of blood flow to the outer peripheral side may be reduced. On the other hand, if the radial width dimension r is larger than 1 mm, the outer diameter dimension of the protrusion provided on the inner peripheral side of the step surface 58 becomes too small, and the effect of changing the direction of blood flow to the outer peripheral side becomes small. There is a risk that blood may not flow smoothly on the stepped surface. In addition, if the radial width dimension r is larger than 1 mm, hemolysis may occur as blood hits the step surface.

The step surface 58 extends in a direction substantially orthogonal to the length direction of the cannula 10, and the inner peripheral edge portion of the step surface 58 and the protruding proximal end of the protruding portion 56 are connected to each other, The outer peripheral edge portion of the step surface 58 and the outermost edge portion of the proximal end surface 54 of the distal end closing portion 50 are connected to each other.

In particular, in the present embodiment, the inner peripheral edge portion of the step surface 58 and the outer peripheral surface 59 at the projecting proximal end of the projecting portion 56 are connected by the projecting distal end side connecting surface 60 as a curved connecting surface that is curved. The outer peripheral edge portion of the surface 58 and the outermost edge portion of the proximal end surface 54 of the distal end closing portion 50 are connected by a protruding proximal end connecting surface 62 that is curved. The projecting distal end side connecting surface 60 has a cross-sectional shape having a curved surface that has a center of curvature on the outer peripheral side of the projecting portion 56 on the outer side and is concave toward the inner side. The side connecting surface 62 has a cross-sectional shape including a curved surface having a curvature center on the inner peripheral side with respect to the outer peripheral surface of the tip closing portion 50 and convex outward.

The distal end side opening portion of the distal end side peripheral wall portion 36 in the distal end tip 14 is closed by the distal end closing portion 50 having such a structure. That is, the distal ends of the

columnar portions

44, 44, 44, 44 of the distal end side peripheral wall portion 36 are integrally formed with the proximal end side end surface 54 of the distal end closing portion 50, or are fixed by welding or bonding. Yes.

Thereby, the protrusion part 56 which protrudes from the base end side end surface 54 of the front-end | tip closing part 50 is located in the inner peripheral side of each

columnar part

44,44,44,44 (front end side peripheral wall part 36), and is length direction Projects to the proximal side. In the present embodiment, the distal ends of the

columnar portions

44, 44, 44, 44 are integrally connected to the protruding proximal end connecting surface 62 that continues from the proximal end surface 54 of the distal end closing portion 50. On the other hand, the protruding

ribs

49, 49, 49, 49 provided on the inner peripheral surfaces of the

columnar portions

44, 44, 44, 44 are the outer peripheral surface 59 of the protruding portion 56, which is the outer peripheral portion 63 of the protruding portion 56, and the protruding tip side. The connecting surface 60, the step surface 58 and the protruding proximal end connecting surface 62 are integrally connected.

Thus, the front end side of the

notches

42 a, 42 a, 42 b, 42 b provided at the front end of the front end side peripheral wall portion 36 is formed by the front end side opening portion of the front end side peripheral wall portion 36 being closed by the front end closing portion 50. The opening is covered with a tip closing portion 50. Thus, window-

like discharge ports

64a, 64a, 64b, and 64b communicating with each other inside and outside are formed on the tip side of the tip tip 14 so as to be separated from each other by a predetermined distance in the circumferential direction.

It should be noted that the length dimension of the

discharge ports

64a and 64a on the upper side in FIG. 2, which is the outer peripheral side of the curved shape of the distal end side peripheral wall portion 36, depends on the length dimension of the

notches

42a, 42a, 42b and 42b. It is made small compared with the length dimension of

discharge port

64b, 64b of the lower side in FIG. 2 used as the inner peripheral side of the curved shape of the side peripheral wall part 36. FIG. Further, the

notches

42a, 42a, 42b, and 42b are configured such that the front end side opening portion gradually expands toward the front end side, and thus the

discharge ports

64a, 64a, 64b, and 64b are provided at the front end side end portions. , The circumferential width dimension gradually increases toward the tip side.

Then, the distal end side opening portion of the distal end side peripheral wall portion 36 is closed by the distal end closing portion 50, whereby the internal flow path 16 of the cannula 10 is closed by the distal end surface (the proximal end side end surface 54 of the distal end closing portion 50). In addition, the internal flow path 16 communicates with the external space through the

discharge ports

64a, 64a, 64b, and 64b at the tip portion. Further, since the distal ends of the

columnar portions

44, 44, 44, 44 are connected to the protruding proximal end connecting surface 62, the step surface 58 located on the inner peripheral side of the protruding proximal end connecting surface 62 is discharged. It is located in the front-end | tip edge part of

exit

64a, 64a, 64b, 64b.

The cannula 10 as described above is used by inserting the tip 14 into the aorta during cardiac surgery. That is, during cardiac surgery, blood taken out of the body is oxygenated by an oxygenator and discharged through the internal channel 16 of the cannula 10 into the aorta. Thus, oxygenated blood can be circulated through the patient's body even during cardiac surgery.

In the present embodiment, since the distal end portion 26 of the distal tip 14 has a curved shape, insertion into the aorta is facilitated. In addition, a locking projection 40 that protrudes to the outer peripheral side is provided at the middle portion in the length direction of the distal tip 14, and the distal tip 14 is brought into contact with the locking projection 40 and the inner wall of the aorta. It can be prevented that it is inserted too deeply into the aorta.

Here, in the cannula 10, the

discharge ports

64a, 64a, 64b, and 64b are provided at the tip portion, and the

columnar portions

44, 44, 44, and 44b positioned between the

discharge ports

64a, 64a, 64b, and 64b in the circumferential direction.

Tapered portions

48, 48, 48, 48 that gradually decrease in the circumferential width dimension toward the distal end side are provided at the distal end portion of 44. The widening structure on the distal end side of the

discharge ports

64a, 64a, 64b, and 64b and the protrusion 56 having the stepped surface 58 on the outer peripheral side act synergistically on the blood flow. By doing so, the blood discharged from the discharge ports 64 and 64 adjacent in the circumferential direction are connected to each other immediately after being discharged from the discharge port 64.

As a result, the blood discharged from the cannula 10 exhibits an umbrella-like or tube-like flow mode in which the blood gradually expands continuously over the entire circumference in the circumferential direction. As a result, it becomes an annular channel width that is connected to the entire circumference in the circumferential direction, and a large channel width is ensured compared to the conventional linear channel width, thereby ensuring blood flow. On the other hand, it becomes possible to reduce the blood flow rate and thus the discharge speed.

9 and 10 showing the experimental results using the prototype having the structure as described in the present embodiment, the state in which the fluid actually introduced from the proximal end side of the cannula 10 is discharged from the distal end. It can be confirmed that the ink is continuously discharged over the entire circumference in the circumferential direction. That is, the fluid discharged from the tip of the cannula 10 becomes a thin-film umbrella-like or tube-like flow continuous over the entire circumference in the circumferential direction, and the diameter gradually increases from the discharge port 64 toward the tip in the discharge direction. After that, a flow mode in which the diameter is gradually reduced is shown.

In the fluid discharge experiment shown in FIGS. 9 and 10, the cannula 10 with φ _C = 6 mm is used and water is used as the fluid, and the fluid is removed from the proximal end side of the cannula 10 using a roller pump. It was made to flow in and was discharged from each discharge port 64. The flow rate of the fluid was 3 L / min. The size (maximum diameter) of the most spread portion in the discharged fluid was approximately 5 cm at a position 60 mm from the discharge port 64 to the tip side.

In this embodiment, since the distal tip 14 of the cannula 10 has a curved shape, insertion into a blood vessel is facilitated. However, the curved shape may cause a difference in the amount of blood discharged through the discharge port 64 between the inner peripheral side and the outer peripheral side of the curved shape, but the discharge port formed on the outer peripheral side of the curved shape. By reducing the size of 64a, 64a (the length dimension in this embodiment) compared to the length dimension of the

discharge ports

64b, 64b formed on the inner peripheral side, the amount of blood to be discharged is made to the entire circumference. It can be made uniform throughout. As a result, even in the curved tip tip 14, blood can be discharged more stably with a continuous flow mode over the entire circumference.

Moreover, since the projecting

ribs

49, 49, 49, 49 are provided on the inner peripheral surfaces of the

columnar portions

44, 44, 44, 44 located between the circumferential directions of the

discharge ports

64a, 64a, 64b, 64b. The strength of each columnar portion 44 can be sufficiently ensured. Further, since the protruding rib 49 has a tapered cross section toward the inner peripheral side, the rectifying effect on the flowing blood is exhibited, and the discharge ports 64 located on both sides in the circumferential direction with respect to the protruding rib 49, The effect of leading to 64 in a diverted state is also exhibited.

Furthermore, since the tip portion of the projecting rib 49 is connected to the projecting portion 56, the strength of the tip portion of the columnar portion 44, which tends to be weakened by providing the tapered portion 48, can be stably secured. Can do.

In addition, the

columnar portions

44, 44, 44, 44 are provided with

equal width portions

46, 46, 46, 46 having substantially constant circumferential width dimensions. , 44 can be more reliably ensured.

Furthermore, since the stepped surface 58 extending in the direction substantially orthogonal to the blood flow is formed on the outer peripheral surface 59 of the protrusion 56, the direction of the blood flow can be changed more stably toward the outer peripheral side. In particular, in the present embodiment, since the projecting distal end side connecting surface 60 and the projecting proximal end side connecting surface 62 are provided at the inner peripheral edge and the outer peripheral edge of the step surface 58, blood smoothly flows. Thus, the risk of hemolysis associated with the blood hitting the wall surface or the like can be effectively reduced.

Next, FIGS. 11 and 12 show a cannula 70 as a second embodiment of the present invention. The cannula 70 of the present embodiment is different from the cannula 10 of the first embodiment in the shape of the distal tip 72, particularly the distal end portion 74. In the description of the present embodiment, members and parts that are substantially the same as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment in the drawings, and detailed description thereof will be given. Omitted.

That is, in the above-described embodiment,

columnar portions

44, 44, 44, 44 are provided between the circumferential directions of the four

discharge ports

64 a, 64 a, 64 b, 64 b in the distal end side portion 26 of the distal tip 14. The end portions on the front end side of the

columnar portions

44, 44, 44, 44 are tapered

portions

48, 48, 48, 48 in which the circumferential width gradually decreases, so that the

columnar portions

44, 44, 44, 44 are The circumferential width at the tip end was narrowed. On the other hand, in the present embodiment, by providing a larger number of discharge ports 76 on the circumference, without providing a tapered portion, that is, while making the circumferential width dimension of the columnar portion 78 substantially constant in the length direction, the columnar shape. The circumferential width dimension at the tip end portion of the portion 78 is narrowed.

Specifically, in the present embodiment, in the distal end side portion 74 of the

distal end tip

72, 20 discharge ports 76 are formed at substantially equal intervals on the circumference, and the discharge ports 76 adjacent in the circumferential direction are formed. , 76, 20 columnar portions 78 are formed as narrow portions. The circumferential width dimension w ′ (see FIG. 12) of the columnar portions 78 constituting the narrow width portion as the opening defining portion is substantially constant in the length direction, and the size is not limited in any way. However, w ′ is preferably 0.6 mm or less, more preferably 0.4 mm or less, and in the present embodiment, it is approximately 0.4 mm. That is, by setting the circumferential width w ′ of the columnar portion 78 to 0.6 mm or less, the discharge ports 76 are positioned close to each other in the circumferential direction at least on the tip side (over the entire length in the present embodiment). A plurality of slit-like discharge ports 76 are formed, and the fluid discharged from these discharge ports 76 can be stably umbrella-shaped or tube-shaped.

Also in the present embodiment, the length dimension of the ten discharge ports 76a on the upper side in FIG. 12, which is the outer peripheral side of the curved shape of the distal end side peripheral wall portion 80, is the inner circumference of the curved shape of the distal end side peripheral wall portion 80. It is made smaller than the length dimension of the ten discharge ports 76b on the lower side in FIG.

The present inventors have also experimented with the cannula 70 configured as described above, and have confirmed that the fluid discharged from the discharge port 76 has an umbrella shape or a tube shape. That is, also in the cannula 70 of this embodiment, the effect similar to the said embodiment can be exhibited.

Although the embodiments of the present invention have been described above, the present invention is not limited to the specific descriptions in the embodiments, and various changes, modifications, improvements, and the like based on the knowledge of those skilled in the art. It is feasible in the form which added.

For example, the number of discharge ports provided in the tip portion of the cannula is not limited to four as described in the first embodiment or 20 as described in the second embodiment, and may be a plurality (two Above)

Further, the shape of the protruding portion is not limited to the conical shape, and may be various tapered shapes such as a pyramid or a hemispherical shape whose bottom is a polygon, such as a triangular pyramid or a quadrangular pyramid, and combinations thereof. Good. Note that the protruding tip of the protruding portion does not need to have a sharp shape, and may have a truncated cone shape, a polygonal frustum shape, a concave shape, etc., but the risk of hemolysis associated with hitting the protruding tip surface is reduced. Therefore, it is preferable to have a sharp shape.

Furthermore, the outer peripheral surface of the projecting portion having a tapered shape (inner peripheral side with respect to the turning portion) does not need to have a substantially constant tilt angle, and the tilt angle may differ depending on the projecting direction of the projecting portion. Note that the inclination angle β of the projecting portion located on the inner peripheral side with respect to the turning portion with respect to the proximal end surface 54 is larger than the inclination angle γ with respect to the proximal end surface 54 of the turning portion (γ <β). However, the protruding portion located on the inner peripheral side of the turning portion may be provided with a portion whose inclination angle is partially smaller than that of the turning portion. That is, the inclination angle on the outer peripheral surface of the protrusion is obtained as an average inclination angle from the apex of the protrusion to the inner peripheral edge of the turning portion.

Furthermore, the size of the radial width dimension r of the step surface (turning portion) may be zero. That is, the protruding proximal end of the protruding portion and the proximal end surface of the distal end closing portion may be connected by one curved surface, and the outer peripheral side portion of the protruding portion is inclined with respect to the proximal end surface 54 rather than the protruding portion. It is only necessary to provide a turning portion with a reduced angle.

Also, a curved surface (curved connecting surface) that connects the protruding proximal end of the projecting portion and the inner peripheral edge of the deflecting portion, or a curved surface that connects the outer peripheral edge of the deflecting portion and the proximal end surface of the distal end closing portion. Neither or both are not mandatory. That is, the projecting proximal end of the projecting portion and the inner peripheral edge of the turning portion may be connected via a linear connecting surface, or the outer peripheral edge of the turning portion and the proximal end surface of the distal end closing portion. May be connected via a linear connecting surface. Further, without providing such a connecting surface, the inner peripheral end and the outer peripheral end of the turning portion may be directly connected to the outer peripheral surface of the protruding portion and the tip closing portion with a corner.

Further, in the above embodiment, the step surface 58 spreads in a direction orthogonal to the length direction of the cannula 10 (that is, substantially parallel to the proximal end surface 54 and inclined angle γ≈0). The step surface (diverting portion) may be widened at a predetermined inclination angle with respect to the length direction of the cannula in such a manner that the inclination angle of the skirt portion of the protruding portion is reduced. The turning portion may have a region that expands in the radial direction at a constant inclination angle, or the inclination angle gradually changes in the radial direction without having a region that expands in the radial direction at a constant inclination angle. An aspect may be sufficient.

Furthermore, in the first embodiment, a uniform width portion 46 having a substantially constant circumferential width dimension is provided over a predetermined length from the base end of the columnar portion 44, while only at the distal end portion of the columnar portion 44. The tapered portion 48 whose circumferential width dimension gradually decreases toward the distal end side is provided, but is not limited to such a mode. That is, for example, the columnar portion may have a tapered shape in which the circumferential width dimension gradually decreases toward the distal end side over substantially the entire length direction.

Further, the tip side portion of the tip is not necessarily curved, and may be, for example, a straight shape. In such a case, each of the plurality of discharge ports may have substantially the same length.

Further, in the above embodiment, the substantially triangular protruding ribs 49 are provided on the inner peripheral surface of the columnar portion 44. However, the cross-sectional shape of the protruding ribs may be a semicircular shape or a polygonal shape equal to or more than a quadrangle. . However, in the present invention, the protruding rib provided on the inner peripheral surface of the columnar portion is not essential.

Although the cannula 10 of the above embodiment is for the aorta, the cannula according to the present invention is not limited to the aorta, and can be applied to a cannula used for blood vessels other than the aorta, for example.

10, 70: cannula, 16: internal flow path, 22: peripheral wall, 44: columnar portion, 48: tapered portion (opening defining portion), 49: protruding rib, 50: tip closing portion, 56: protruding portion, 58: Step surface (turning portion), 59: outer peripheral surface, 60: projecting distal end side connecting surface (curved connecting surface), 62: projecting proximal end side connecting surface, 64, 64a, 64b, 76, 76a, 76b: discharge port, 78: Columnar portion (opening defining portion) as narrow portion

Claims

In the cannula in which the internal flow path extending from the proximal end side toward the distal end side is closed at the distal end surface, and a plurality of discharge ports are provided apart from each other in the circumferential direction on the peripheral wall of the distal end portion.
On the inner peripheral side of the peripheral wall of the tip portion where the plurality of discharge ports are provided, a protruding portion that protrudes from a tip closing portion that closes the internal flow path at the tip surface is provided,
On the outer peripheral side portion of the protruding portion in the tip closing portion, a turning portion in which the inclination angle of the outer peripheral surface of the protruding portion is reduced is formed,
At least the end portion on the tip side of the columnar portion made of the peripheral wall extending in the length direction between the plurality of discharge ports adjacent to each other in the circumferential direction defines the opening width of each discharge port. A cannula characterized in that the cannula is an opening defining portion that continuously guides and discharges the blood flow guided in the circumferential direction.
As the opening defining portion, a tapered portion having a circumferential width gradually narrowing at least at an end portion on the tip side of the columnar portion is provided so that the circumferential width of each discharge port is gradually increased toward the tip. The cannula of claim 1.
2. The cannula according to claim 1, wherein the opening defining portion is provided with a narrow width portion having a circumferential width dimension of 0.6 mm or less at least at an end portion on a distal end side of the columnar portion.
The cannula according to any one of claims 1 to 3, wherein the columnar part is provided with a protruding rib that protrudes in a tapered direction toward the inner peripheral side and extends in the length direction.
The cannula according to claim 4, wherein the protruding rib is connected to an outer peripheral portion of the protruding portion in the distal end closing portion at an end portion on a distal end side of the columnar portion.
The cannula according to any one of claims 1 to 5, wherein the columnar portion extends with a constant circumferential width over a predetermined length on a proximal end side.
The cannula according to any one of claims 1 to 6, wherein a curved connecting surface that is smoothly connected to an outer peripheral surface of the projecting portion is provided at an inner peripheral edge portion of the turning portion.
The distal end portion has a curved shape, and the discharge port located on the outer peripheral side of the curved shape has a smaller length than the discharge port located on the inner peripheral side of the curved shape. The cannula according to any one of claims 1 to 7.