JP6788792B2 - Cannula - Google Patents

Description

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

Conventionally, there is known a cannula that is inserted into a blood vessel to allow blood to flow in an internal flow path. For example, Japanese Patent Application Laid-Open No. 8-196624 (Patent Document 1) proposes a cannula that is inserted into the aorta and used 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 circulated 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 become a jet stream and hit the inner wall of the blood vessel. In such a case, the vigorously spouted blood may damage the blood vessel, and for example, the thrombus adhering to the blood vessel may be peeled off and flowed downstream, causing 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 on the peripheral wall of the tip portion, and blood is discharged from the cannula in a dispersed manner through the plurality of discharge ports. We are trying to reduce the flow velocity of the discharged blood.

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

Japanese Unexamined Patent Publication No. 8-196624

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

Hereinafter, aspects of the present invention made to solve such problems will be described. The components adopted in each of the following aspects can be adopted in any combination as much as possible.

In the first aspect of the present invention, an internal flow path extending from the proximal end side toward the distal end side is closed on the distal end surface, and a plurality of discharge ports are provided on the peripheral wall of the distal end portion apart from each other in the circumferential direction. In a cannula in which blood flow is discharged from the plurality of discharge ports toward the tip side, the internal flow path is set on the inner peripheral side of the peripheral wall of the tip portion provided with the plurality of discharge ports. A projecting portion that protrudes from the tip closing portion that closes on the surface is provided, and a turning portion in which the inclination angle of the outer peripheral surface of the protruding portion is reduced on the outer peripheral side portion of the protruding portion in the tip closing portion. At least the tip end side of the columnar portion formed 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. It is characterized in that the blood flow guided and discharged by the turning portion is provided as an opening defining portion that is mutually continuous in the circumferential direction.

According to the cannula having a structure according to this aspect, the protrusions are provided on the inner peripheral side of the plurality of discharge ports, and the inclination angle of the outer peripheral surface of the protrusions is small on the outer peripheral side of the protrusions. Since the converted portion is formed, the flow direction of blood is changed by hitting the converted 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. In addition, the blood flow guided by the turning portion and discharged from the discharge port is continuously connected to each other in the circumferential direction by the opening defining portion of the discharge port. Then, due to the synergistic action of these turning portions and the opening defining portion, the blood flow discharged from the tip of the cannula is discharged in a hollow tube-shaped or umbrella-shaped flow mode that spreads in the discharge direction as a whole. It will be. As a result, the speed can be efficiently suppressed while ensuring the flow rate of blood discharge, and damage to blood vessels can be reduced.

A second aspect of the present invention is that, in the cannula according to the first aspect, the opening defining portion is provided with a tapered portion whose circumferential width gradually narrows at least at the end portion on the distal end side of the columnar portion. As a result, the circumferential width of each discharge port is gradually increased toward the tip.

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

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

According to the cannula having a structure according to this aspect, a columnar portion extending in the length direction is provided between the circumferential directions of the discharge port, and the circumferential width dimension at the tip end side of the columnar portion is 0. It is narrowed to 1.6 mm or less. That is, the separation distance between the discharge ports adjacent to each other in the circumferential direction can be reduced, and the blood discharged from the discharge ports adjacent to each other in the circumferential direction can be discharged by the synergistic action of the turning portion and the narrow width portion. It can be connected to each other more efficiently.

A fourth aspect of the present invention is that 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 cross section toward the inner peripheral side and extends in the length direction. It is what has been done.

According to the cannula having a structure according to this aspect, since the protruding ribs are provided on the inner peripheral side of the columnar portion, sufficient strength in the columnar portion is secured. In particular, since the protruding ribs are formed so as to extend in the length direction in a cross-sectional shape that tapers toward the inner peripheral side, there is 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 tip closing portion at the distal end side end portion of the columnar portion. It is what has been done.

According to the cannula having a structure according to this aspect, since the tip 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 a tapered portion is provided in the columnar portion. In addition, the strength of the tip end side of the columnar portion, which tends to be weak, can be improved more reliably.

A sixth aspect of the present invention is that 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 a structure according to this aspect, since the columnar portion has a constant circumferential width dimension over a predetermined length on the proximal end side, the strength of the columnar portion is more stably secured. obtain.

A seventh aspect of the present invention is that in the cannula according to any one of the first to sixth aspects, the inner peripheral edge portion of the turning portion is smoothly connected to the outer peripheral surface of the protruding portion. Is provided.

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

In the eighth aspect of the present invention, in the cannula according to any one of the first to seventh aspects, the tip portion has a curved shape, and the discharge port located on the outer peripheral side of the curved shape has the curved shape. The length is smaller than that of the discharge port located on the inner peripheral side of the curved shape.

According to the cannula having a structure according to this aspect, since the tip portion has a curved shape, the cannula can be more easily inserted into the blood vessel. In addition, the difference in blood flow rate discharged from each discharge port due to the curved shape of the tip of the cannula can be reduced by the relative setting of the length dimension of the discharge port, and the entire circumference can be reduced. 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 rate while ensuring the flow rate of the discharged blood.

The perspective view which shows the tip part in the cannula as the 1st Embodiment of this invention. The front view of the tip portion in the cannula shown in FIG. The front view which shows the main part in FIG. 2 enlarged. Top view of the tip portion of the cannula shown in FIG. Bottom view of the tip portion of the cannula shown in FIG. The vertical sectional view of the tip portion in the cannula shown in FIG. FIG. 6 is an enlarged vertical sectional view showing a main part in FIG. FIG. 6 is a sectional view taken along line VIII-VIII in FIG. It is explanatory drawing for demonstrating the state which discharged the fluid using the cannula shown in FIG. 1 from the side view. An explanatory view for explaining a state in which a fluid is discharged using the cannula shown in FIG. 1 with a rear view different from that in FIG. The perspective view which shows the tip part in the cannula as the 2nd Embodiment of this invention. The front view which shows the main part in FIG. 11 enlarged.

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

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

More specifically, the cannula body 12 has a flexible tubular shape, and is made of polyamide, polyvinyl chloride, polyurethane, polyimide, polyethylene, polyethylene elastomer, polypropylene, polytetrafluoroethylene, polyether ketone, or polyvinylidene fluoride. It is formed of a soft synthetic resin such as vinylidene. The cannula main body 12 is provided with 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. The cannula main body may be reinforced by embedding a braided wire made of metal or the like, a coil spring such as a circular cross-section spring or a square spring, or the like inside the peripheral wall 18, for example.

A tip tip 14 is attached to the tip end side of the cannula body 12. The tip 14 has a substantially tubular shape as a whole, and is made of a hard synthetic resin such as polypropylene, polycarbonate, polyester, polyvinyl chloride, or polyurethane. That is, the tip tip 14 is provided with 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 main body 12 and the inner hole 24 of the tip tip 14 are communicated with each other, and these inner holes 20 and 24 form the internal flow path 16 of the cannula 10.

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

That is, the proximal end side portion 28 of the tip tip 14 has a substantially tapered tubular shape extending substantially linearly, and has a proximal end side peripheral wall portion 30 having a substantially constant wall thickness dimension and the proximal end side peripheral wall portion 30. The base end side inner hole 32 formed on the inner peripheral side of the above is provided. The inner peripheral surface and the outer peripheral surface of the base end side peripheral wall portion 30 are gradually reduced in inner diameter dimension and outer diameter dimension toward the tip end side. Since the cannula 10 of the present embodiment is intended for the aorta, it is thicker than the cannula for other blood vessels. The specific dimensions are set according to the application and are not limited, but for example, the inner diameter dimension φ _A (see FIG. 6) at the proximal end portion of the proximal 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 approximately 4 to 20 mm.

Further, the base end side peripheral wall portion 30 having such a substantially tapered tubular shape is provided with a connecting cylinder portion 34 protruding toward the base end side. The inner diameter of the connecting cylinder portion 34 is substantially equal to the inner diameter dimension at the proximal end of the proximal end side peripheral wall portion 30 (maximum inner diameter dimension of the proximal end side peripheral wall portion 30). On the other hand, the outer diameter of the connecting cylinder portion 34 is gradually increased toward the proximal end side as compared with the outer diameter dimension at the proximal end of the proximal end side peripheral wall portion 30 (maximum outer diameter dimension of the proximal end side peripheral wall portion 30). Has been made smaller. The tip portion of the cannula main body 12 is extrapolated to the connection cylinder portion 34, and is fixed by welding, adhesion, caulking fixing, etc. as necessary, whereby the cannula main body 12 and the tip tip 14 are connected to each other. It is supposed to be done.

On the other hand, the tip side portion 26 of the tip tip 14 has a curved tubular shape that curves downward in FIG. 2, and the tip side peripheral wall portion 36 having a substantially constant wall thickness dimension and the tip side peripheral wall portion 36. The 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 by including the tip side peripheral wall portion 36 and the proximal end side peripheral wall portion 30, and the tip end side inner hole 38 and the proximal end side inner hole 32 are included. The inner hole 24 of 14 is configured.

The inner diameter dimension and the outer diameter dimension of the tip end side peripheral wall portion 36 are substantially constant in the length direction, and the inner diameter dimension of the tip end side peripheral wall portion 36 is the inner diameter dimension (base end) at the tip of the proximal end side peripheral wall portion 30. It is substantially equal to the minimum inner diameter of the side peripheral wall portion 30). As a result, the inner peripheral surface (tip 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 tip of the proximal end side peripheral wall portion 30 (minimum outer diameter dimension of the proximal end side peripheral wall portion 30). Since the cannula 10 of the present embodiment is intended for the aorta, it is thicker than the cannula for other blood vessels. The specific dimensions are set according to the application and are not limited, but for example, the inner diameter dimension φ _C (see FIG. 6) of the tip side peripheral wall portion 36 is about 1 to 14 mm, while the tip side peripheral wall. 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 the present 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 protrusion 40 projecting to the outer peripheral side. The locking protrusion 40 has a substantially semicircular vertical cross section and has a substantially annular shape extending continuously over substantially the entire circumference in the circumferential direction, and the maximum outer diameter dimension of the locking protrusion 40 is large. , It is made larger than the outer diameter dimension at the tip of the base end side peripheral wall portion 30. 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.

At the tip of the tip-side peripheral wall portion 36, a plurality of notches 42 that open to the tip side are formed. 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 notches 42 are substantially equal. On the other hand, the length dimensions of two notches 42, 42 of these notches 42 are different from the length dimensions of the remaining two notches 42, 42. That is, in the tip side peripheral wall portion 36, the upper notches 42a and 42a in FIG. 2 located on the outer peripheral side of the curved shape are located on the inner peripheral side of the curved shape, and the lower notches 42b in FIG. , 42b, the length dimension is smaller than that of 42b.

By forming the notches 42a, 42a, 42b, 42b as described above, a columnar portion 44 composed of a peripheral wall portion 36 on the distal end side and extending in the longitudinal direction is formed between the notches 42, 42 adjacent to each other in the circumferential direction. , 44, 44, 44 are formed.

Each of the notches 42a, 42a, 42b, and 42b is formed with a substantially constant circumferential width dimension from the base end portion over a predetermined length, while the tip end side opening faces the tip end side. It is gradually expanding. That is, the columnar portions 44, 44, 44, 44 formed between the notches 42, 42 adjacent to each other in the circumferential direction have a substantially constant circumferential width dimension from the proximal end side over a predetermined length dimension. The monospaced portions 46, 46, 46, 46 having the same width are formed. On the other hand, at the tips of the columnar portions 44, 44, 44, 44, tapered portions 48, 48, 48, 48 whose circumferential width dimension gradually decreases toward the tip side are formed. Therefore, in the present embodiment, the tapered portions 48, 48, 48, 48 are provided at the distal end portions of the columnar portions 44, 44, 44, 44, so that the circumferential width dimension thereof is narrowed and the opening is opened. The regulation part is composed.

The circumferential width dimension of the columnar portions 44, 44, 44, 44 is not limited in any way, but the circumferential width dimension at the tip of the columnar portion 44, 44, 44, 44 (tapered portion 48, 48). , 48, 48, the minimum circumferential width dimension) w (see FIG. 3) is preferably 0.6 mm or less, more preferably 0.4 mm or less, and is approximately 0 in the present embodiment. It is said to be 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, the fluid discharged from the discharge port 64 can be stably formed into an umbrella shape or a tube shape, as will be described later.

Further, protruding ribs 49, 49, 49, 49 having a predetermined length dimension and projecting to the inner peripheral side are formed on the inner peripheral surfaces of the columnar portions 44, 44, 44, 44, respectively. .. In the present embodiment, the protruding ribs 49, 49, 49, 49 have substantially the same shape and have substantially the same length dimension, and are formed with a tapered cross section, respectively. The protruding ribs 49, 49, 49, 49 reinforce the columnar portions 44, 44, 44, 44 whose peripheral width dimension is reduced by being provided on the tapered portions 48, 48, 48, 48, and further. 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. Then, the protruding ribs 49, 49, 49, 49 are formed so as to extend over substantially the entire length of the columnar portions 44, 44, 44, 44, or further extend to the proximal end side from the columnar portions 44, 44, 44, 44. Has been done. In the present embodiment, the protruding ribs 49, 49, 49, 49 have a substantially triangular cross section, and the corners are rounded.

The tip-side opening of the tip-side peripheral wall portion 36 having such a structure is closed by the tip closing portion 50. The tip closing portion 50 is integrally formed with the tip side peripheral wall portion 36 or the like, or is fixed after being formed separately from the tip side peripheral wall portion 36 or the like. The tip closing portion 50 has a cylindrical block shape as a whole, and its outer diameter dimension is substantially equal to the outer diameter dimension of the tip 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 from each other, and the proximal end side end surface 54 of the distal end closing portion 50 is the distal end side of the distal end side peripheral wall portion 36. While extending substantially perpendicular to the opening, the distal end surface 52 of the distal closing portion 50 extends at a predetermined inclination angle with respect to the proximal end surface 54.

In the present embodiment, in the tip closing portion 50, the length dimension on the upper side in FIG. 2, which is the outer peripheral side of the curved shape of the tip side peripheral wall portion 36, is the inner peripheral side of the curved shape of the tip side peripheral wall portion 36. It is shorter than the lower length dimension in FIG. The tip closing portion 50 has a rounded chamfered shape with rounded corners on the outer peripheral edge of the cutting edge surface. As described above, since the distal end surface 52 of the distal end closing portion 50 has a predetermined inclination angle with respect to the proximal end surface 54, the tip of the cannula 10 can be easily inserted into the aorta.

Further, a tapered protruding portion 56 protrudes from the proximal end side end surface 54 of the tip closing portion 50, and in the present embodiment, the protruding portion 56 protrudes from a substantially central portion of the proximal end side end surface 54. Further, the protruding portion 56 of the present embodiment has a substantially conical shape, and the central axis of the protruding portion 56 is coaxially or slightly inclined with the central axis of the distal end side end surface 54 of the tip closing portion 50. That is, it projects in a direction substantially orthogonal to the base end side end surface 54 or substantially coaxially with the central axis of the tip end side peripheral wall portion 36.

The protruding tip, which is the top of the protruding portion 56, may have a sharp shape or may be rounded. Further, in the vertical cross section shown in FIG. 7, the central angle α of the protruding portion 56 corresponding to the apex angle of the cone is preferably 30 degrees to 50 degrees. That is, if the central angle α is smaller than 30 degrees, the protruding portion may have 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 protruding portion with respect to the blood flow direction becomes too large, and it may be difficult to realize a smooth flow of blood. The protrusion height dimension t of the protrusion 56 is preferably 5 mm to 10 mm. That is, if the protruding 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 it may be difficult to realize a smooth flow of blood. On the other hand, if the protruding height dimension t is larger than 10 mm, the protruding portion 56 may become longer than necessary and the flow path may be narrowed with the distal end side peripheral wall portion 36.

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

Since the stepped surface 58 is provided 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 β of the outer peripheral surface 59 on the protruding tip side of the protruding portion 56 with respect to the proximal end side end surface 54 (see FIG. 7) with respect to the proximal end side end surface 54 of the stepped surface 58. γ (see FIG. 7) is reduced (γ <β), and in the present embodiment, γ is set to approximately 0 degrees (γ≈0). Therefore, in the present embodiment, in the outer peripheral side portion of the protruding portion 56, a turning portion for reducing the inclination angle of the outer peripheral surface 59 of the protruding portion 56 is formed by the stepped surface 58.

The radial width dimension r of the stepped 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. Further, when 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 stepped surface 58 becomes too small, and the action of changing the blood flow direction to the outer peripheral side becomes small. There is a risk that blood will not flow smoothly due to the stepped surface. In addition, if the radial width dimension r is larger than 1 mm, hemolysis may occur as the blood hits the stepped surface.

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

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

The tip closing portion 50 having such a structure closes the tip side opening of the tip side peripheral wall portion 36 in the tip tip 14. That is, the tips of the columnar portions 44, 44, 44, 44 of the tip side peripheral wall portion 36 are integrally formed with the proximal end side end surface 54 of the tip closing portion 50, or are fixed by welding or adhesion. There is.

As a result, the protruding portion 56 protruding from the base end side end surface 54 of the tip closing portion 50 is located on the inner peripheral side of each columnar portion 44, 44, 44, 44 (tip side peripheral wall portion 36) in the length direction. It protrudes to the base end side. In the present embodiment, the tips of the columnar portions 44, 44, 44, 44 are integrally connected to the projecting base end side connecting surface 62 continuous from the base end side end surface 54 of the tip 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 and the protruding tip side of the protruding portion 56, which is the outer peripheral portion 63 of the protruding portion 56. It is integrally connected to the connecting surface 60, the stepped surface 58, and the projecting base end side connecting surface 62.

In this way, the front end side opening of the tip side peripheral wall portion 36 has a closed structure by the tip closing portion 50, so that the tip side of the notches 42a, 42a, 42b, 42b provided at the tip of the tip side peripheral wall portion 36 The opening is covered by the tip closure portion 50. As a result, window-shaped discharge ports 64a, 64a, 64b, 64b that communicate 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 port 64a, 64a on the upper side in FIG. 2, which is the outer peripheral side of the curved shape of the peripheral wall portion 36 on the tip side, corresponds to the length dimension of the notches 42a, 42a, 42b, 42b. The length of the discharge ports 64b and 64b on the lower side in FIG. 2, which is the inner peripheral side of the curved shape of the side peripheral wall portion 36, is smaller than the length dimension. Further, since the tip side openings of the notches 42a, 42a, 42b, 42b are gradually widened toward the tip side, the discharge ports 64a, 64a, 64b, 64b are the tip side end portions. In, the circumferential width dimension gradually increases toward the tip side.

Then, the front end side opening of the front end side peripheral wall portion 36 is closed by the tip closing portion 50, so that the internal flow path 16 of the cannula 10 is closed by the tip surface (base end side end surface 54 of the tip closing portion 50). At the same time, the internal flow path 16 is communicated with the external space through the discharge ports 64a, 64a, 64b, 64b at the tip portion. Further, since the tips of the columnar portions 44, 44, 44, 44 are connected to the protruding base end side connecting surface 62, the stepped surface 58 located on the inner peripheral side of the protruding base end side connecting surface 62 discharges. It is located at the tip edge of the outlets 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 artificial heart-lung machine and discharged into the aorta via the internal flow path 16 of the cannula 10. This makes it possible for oxygenated blood to be circulated in the patient's body even during cardiac surgery.

In the present embodiment, since the tip end side portion 26 of the tip tip 14 has a curved shape, it can be easily inserted into the aorta. Further, a locking protrusion 40 projecting to the outer peripheral side is provided at the intermediate portion in the length direction of the tip tip 14, and the tip tip 14 is brought into contact with the locking protrusion 40 and the inner wall of the aorta. It can be prevented from being inserted too deep into the aorta.

Here, in the cannula 10, the discharge ports 64a, 64a, 64b, 64b are provided at the tip portions, and the columnar portions 44, 44, 44, located between the discharge ports 64a, 64a, 64b, 64b in the circumferential direction, The tip portion of the 44 is provided with tapered portions 48, 48, 48, 48 whose circumferential width dimension gradually decreases toward the tip side. Then, the widening structure on the tip side of the discharge ports 64a, 64a, 64b, 64b and the protruding portion 56 having the stepped surface 58 on the outer peripheral side portion synergistically act as a rectifying effect on the blood flow. By doing so, the blood discharged from the discharge ports 64 and 64 adjacent to each other in the circumferential direction is 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-shaped or tube-shaped flow mode in which the blood is continuously and gradually expanded over the entire circumference in the circumferential direction as a whole. As a result, the width of the annular flow path is connected all around the circumference in the circumferential direction, and a large flow path width is secured as compared with the conventional linear flow path width, so that the blood flow amount is secured. At the same time, it is possible to reduce the blood flow velocity and thus the discharge rate.

Incidentally, in FIGS. 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 inflowed from the proximal end side of the cannula 10 is discharged from the tip. Is shown, and it can be confirmed that the fluid is continuously discharged over the entire circumference in the circumferential direction. That is, the fluid discharged from the tip of the cannula 10 becomes an umbrella-shaped or tube-shaped flow of a thin film that is continuous over the entire circumference in the circumferential direction, and gradually expands in diameter from the discharge port 64 toward the tip side in the discharge direction. After that, it shows a flow mode in which the diameter is gradually reduced.

In the fluid discharge experiment shown in FIGS. 9 and 10, a cannula 10 having a diameter of _C = 6 mm was used and water was used as the fluid, and the fluid was fed from the proximal end side of the cannula 10 using a roller pump. It was allowed 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 widened portion of the discharged fluid was approximately 5 cm at a position 60 mm from the discharge port 64 to the tip side.

In the present embodiment, since the tip 14 of the tip of the cannula 10 has a curved shape, it can be easily inserted into a blood vessel. 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 making the sizes of 64a and 64a (length dimensions in this embodiment) smaller than the length dimensions of the discharge ports 64b and 64b formed on the inner peripheral side, the amount of blood discharged can be increased to the entire circumference. It can be homogenized over. As a result, even in the curved tip 14, blood can be discharged more stably with a continuous flow mode over the entire circumference in the circumferential direction.

Further, since the protruding ribs 49, 49, 49, 49 are provided on the inner peripheral surfaces of the columnar portions 44, 44, 44, 44 located between the discharge ports 64a, 64a, 64b, 64b in the circumferential direction. , The strength of each columnar portion 44 can be sufficiently secured. Further, since the protruding rib 49 has a tapered cross section toward the inner peripheral side, a rectifying effect on flowing blood is exhibited, and discharge ports 64 located on both sides in the circumferential direction with respect to the protruding rib 49, It also exerts the action of leading to 64 in a split flow manner.

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

In addition, since the columnar portions 44, 44, 44, 44 are provided with the equal width portions 46, 46, 46, 46 having substantially constant circumferential width dimensions, the columnar portions 44, 44, 44 , 44 strength can be secured more reliably.

Furthermore, since the outer peripheral surface 59 of the protruding portion 56 is formed with a stepped surface 58 extending in a direction substantially orthogonal to the blood flow, the direction of the blood flow can be changed more stably to the outer peripheral side. In particular, in the present embodiment, since the protruding tip side connecting surface 60 and the protruding base end side connecting surface 62 are provided on the inner peripheral edge portion and the outer peripheral edge portion of the stepped surface 58, blood flows smoothly. Therefore, the risk of hemolysis due to 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 shape of the tip tip 72, particularly the tip side portion 74, of the cannula 70 of the present embodiment is different from that of the cannula 10 of the first embodiment. In the description of the present embodiment, the members and parts substantially the same as those of the first embodiment will be described in detail by adding the same reference numerals as those of the first embodiment in the drawings. Omit.

That is, in the above embodiment, in the tip end side portion 26 of the tip tip 14, columnar portions 44, 44, 44, 44 are provided between the circumferential directions of the four discharge ports 64a, 64a, 64b, 64b. The ends of the columnar portions 44, 44, 44, 44 on the distal end side are tapered portions 48, 48, 48, 48 whose circumferential width gradually narrows, so that the columnar portions 44, 44, 44, 44 The circumferential width at the tip side end was narrowed. On the other hand, in the present embodiment, by providing a larger number of discharge ports 76 on the circumference, the columnar portion 78 is not provided, that is, the columnar portion 78 is substantially constant in the circumferential width dimension in the length direction. The circumferential width dimension at the distal end of the portion 78 is narrowed.

Specifically, in the present embodiment, in the tip end side portion 74 of the tip tip 72, 20 discharge ports 76 are formed at substantially equal intervals on the circumference, and the discharge ports 76 adjacent to each other in the circumferential direction. A columnar portion 78 as 20 narrow width portions is formed between the and 76. The circumferential width dimension w'(see FIG. 12) of these 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. Although not, w'is preferably 0.6 mm or less, more preferably 0.4 mm or less, and in the present embodiment, about 0.4 mm. That is, since the circumferential width w'of the columnar portion 78 is 0.6 mm or less, the discharge port 76 is located at least on the tip side (over the entire length in the present embodiment) in close proximity to each other in the circumferential direction. A plurality of slit-shaped discharge ports 76 are provided, and the fluid discharged from these discharge ports 76 can be stably formed into an umbrella shape or a tube shape.

Also in this 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 wall portion 80, is the inner circumference of the curved shape of the distal wall portion 80. It is smaller than the length dimension of the lower 10 discharge ports 76b in FIG. 12, which are on the side.

The present inventors also conducted experiments on the cannula 70 having the above-mentioned structure, and confirmed that the fluid discharged from the discharge port 76 has an umbrella shape or a tube shape. That is, the same effect as that of the above-described embodiment can be exhibited in the cannula 70 of the present embodiment.

Although the embodiments of the present invention have been described above, the present invention is not limitedly interpreted by the specific description in the embodiments, and various changes, modifications, improvements, etc. are made based on the knowledge of those skilled in the art. It can be carried out in the form of adding.

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

Further, the shape of the protruding portion is not limited to a conical shape, and even if it is a pyramid or a hemispherical shape having a polygonal bottom surface such as a triangular pyramid or a quadrangular pyramid, or various tapered shapes such as a combination thereof. Good. The protruding tip of the protruding portion does not have to have a sharpened shape, and may have a truncated cone shape, a truncated cone shape, a concave shape, or the like, but the risk of hemolysis due to hitting the protruding tip surface is reduced. Therefore, it is preferable to have a sharpened shape.

Further, the outer peripheral surface of the tapered protruding portion (inner peripheral side of the turning portion) does not have to have a substantially constant inclination angle, and the inclination angle may differ depending on the protruding direction of the protruding portion. The inclination angle β of the protrusion located on the inner peripheral side of the turning portion with respect to the base end side end surface 54 is made larger than the inclination angle γ with respect to the proximal end side 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 protruding portion is obtained as the average inclination angle from the apex of the protruding portion to the inner peripheral edge portion of the turning portion.

Furthermore, the size of the radial width dimension r of the stepped surface (converted portion) may be set to 0. That is, the protruding base end of the protruding portion and the proximal end side end surface of the tip 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 side end surface 54 rather than the protruding portion. It suffices to provide a turning portion with a reduced angle.

Further, a curved surface (curved articulated surface) connecting the protruding base end of the protruding portion and the inner peripheral edge portion of the turning portion, or a curved surface connecting the outer peripheral edge portion of the turning portion and the proximal end side end surface of the tip closing portion. , Or both are not required. That is, the protruding base end of the projecting portion and the inner peripheral edge portion of the diversion portion may be connected via a linear connecting surface, or the outer peripheral edge portion of the diversion portion and the proximal end side end surface of the tip closing portion. May be connected via a linear articulating 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 or the tip closing portion with a corner portion.

Further, in the above-described embodiment, the stepped surface 58 extends in a direction orthogonal to the length direction of the cannula 10 (that is, substantially parallel to the base end side end surface 54 and an inclination angle γ≈0). The stepped surface (converted portion) may be widened at a predetermined inclination angle with respect to the length direction of the cannula in an manner of reducing the inclination angle of the hem portion of the protruding portion. The turning portion may have a region extending in the radial direction at a constant inclination angle, or the inclination angle gradually changes in the radial direction without having a region extending in the radial direction at a constant inclination angle. It may be an embodiment.

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

Further, the tip end side portion of the tip tip does not have to be curved, and may be linear, for example. In such a case, the plurality of discharge ports may have substantially the same length dimension.

Further, in the above-described embodiment, the projecting rib 49 having a substantially triangular shape is provided on the inner peripheral surface of the columnar portion 44, but the cross-sectional shape of the projecting rib may be a semicircular shape or a polygonal shape of a quadrangle or more. .. 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 intended for the aorta, the cannula according to the present invention is not limited to the aorta, and can be applied to, for example, a cannula used for a blood vessel other than the aorta.

10, 70: Cannula, 16: Internal flow path, 22: Peripheral wall, 44: Columnar part, 48: Tapered part (opening regulation part), 49: Protruding rib, 50: Tip closing part, 56: Protruding part, 58: Step surface (converted part), 59: outer peripheral surface, 60: projecting tip side connecting surface (curved connecting surface), 62: protruding base end side connecting surface, 64, 64a, 64b, 76, 76a, 76b: discharge port, 78: Columnar portion as a narrow width portion (opening regulation portion)

Claims (8)

An internal flow path extending from the base end side to the tip end side is closed on the tip end surface, and a plurality of discharge ports are provided on the peripheral wall of the tip end portion in the circumferential direction so as to be separated from each other. In a cannula where blood flow is discharged toward the tip side
On the inner peripheral side of the peripheral wall of the tip portion provided with the plurality of discharge ports, a projecting portion protruding from the tip closing portion that closes the internal flow path on 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, while
At least the tip end portion of the columnar portion formed 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 it is an opening regulation part that makes the blood flow guided and discharged by the above continuous with each other in the circumferential direction. As the opening defining portion, a tapered portion whose circumferential width gradually narrows is provided at least at the end portion on the tip side of the columnar portion, so that the circumferential width of each discharge port is gradually increased toward the tip. The cannula according to claim 1. The cannula according to claim 1, wherein a narrow portion having a circumferential width dimension of 0.6 mm or less at at least the end portion on the distal end side of the columnar portion is provided as the opening defining portion. The cannula according to any one of claims 1 to 3, wherein the columnar portion is provided with a protruding rib that protrudes in a tapered cross section toward the inner peripheral side and extends in the length direction. The cannula according to claim 4, wherein at the distal end of the columnar portion, the protruding rib is connected to an outer peripheral portion of the protruding portion in the tip closure. 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 the proximal end side. The cannula according to any one of claims 1 to 6, wherein the inner peripheral edge portion of the turning portion is provided with a curved articulated surface that smoothly connects to the outer peripheral surface of the protruding portion. The tip 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.