Patent Description:
For artificial dialysis, a catheter provided with a blood removal lumen which removes blood from the subject's body and a blood return lumen which returns the purified blood to the subject's body is used. Further, a quadruple-lumen catheter is known, which can handle cases where it is necessary to perform administration of drug solution, measurement of central venous pressure, or the like concurrently with the hemodialysis (e.g., see Patent Document <NUM>). Such a quadruple-lumen catheter is further provided with two infusion lumens in addition to the blood removal lumen and the blood return lumen. This eliminates the need for preparing a new route for the administration of drug solution or the measurement of central venous pressure, thereby reducing the burden on an operator and the patient.

When blood is sucked through the blood removal lumen, there would be such a case that the inner wall of blood vessel stick to an opening of the blood removal lumen due to the suction pressure. This would cause such a drawback that the opening of the blood removal lumen is blocked, thereby causing blood removal failure or a decrease in removal blood flow rate. In some cases, the drawback would be solved by reverse connection in which the blood removal lumen and the blood return lumen are exchanged to return the blood through the blood removal lumen, thereby solving sticking of the inner wall of the blood vessel to the opening (e.g., see Patent Document <NUM>).

<CIT> discloses a multi-lumen catheter including an elliptical cross-sectional profile configuration that enhances fluid flow rate while minimizing the average diameter of the catheter body. In one embodiment the catheter includes an elongate catheter tube defining a plurality of lumens. At least a portion of the longitudinal length of the catheter tube may define an elliptical cross section, in turn defined by a major axis and a minor axis. In one embodiment, a ratio of the major axis to the minor axis of the elliptical cross section is between about <NUM> and about <NUM>. The catheter body can define two, three, or more lumens. In one embodiment, a dual-lumen catheter tube includes an aspect ratio of about <NUM>:<NUM>, and each lumen thereof includes an inner surface defined by a plurality of radii and an hourglass-shaped septum.

<CIT> discloses a catheter including: a blood return lumen which is arranged in a first region and communicates with the outside via an opening part provided in a distal end part; a blood removal lumen which is arranged in a second region and communicates with the outside via a semicircular opening part arranged on a proximal end part side with respect to the opening part of the blood return lumen; three or more transfusion lumens arranged in the first region; and a narrow diameter part which is provided from the opening part of the blood removal lumen to the distal end part, has the blood return lumen and three or more transfusion lumens in the inside, and has a taper so that a diameter is reduced gradually toward the distal end part. Then, a cross section of the blood return lumen is formed to be bigger than cross sections of the respective transfusion lumens. The opening part of the blood removal lumen is slanted to the proximal end part side in an axial direction. The respective opening parts of the transfusion lumens are arranged in the narrow diameter part and are formed to follow the taper of the narrow diameter part.

<CIT> discloses a dialysis catheter including a first portion having an outer wall having a first diameter, an elongated distal portion having a second diameter smaller than the first diameter, and a transition region between the first portion and distal portion. A first longitudinally extending venous lumen is configured to deliver blood. First and second independent longitudinally extending arterial lumens are configured to withdraw blood from a patient. The venous lumen and arterial lumen have first and second regions each positioned a first distance from the outer wall of the catheter and a third region positioned a second distance, which is shorter than the first distance, from the outer wall of the catheter to form an arch-shaped wall portion progressively increasing in thickness from the third region toward the first region and from the third region to the second region.

<CIT> discloses a catheter assembly including an elongate catheter tube. The number of lumens defined by the catheter tube can vary as a function of longitudinal length along the catheter tube. For instance, the catheter tube can define three lumens from the proximal end of the catheter tube and terminate one of the lumens at an intermediate termination point such that only two lumens are defined further distally along the catheter tube. A sensor can be placed in the terminating lumen so as to isolate it from the other lumens and from blood or other body fluids while still enabling the sensor to reside within the patient body when the catheter tube is positioned in the patient for use. In addition to this, various other lumen transition and sensor configurations are disclosed.

The quadruple-lumen catheter disclosed in Patent Document <NUM> is provided with a blood return lumen in a distal end portion of the catheter. Thus, the quadruple-lumen catheter disclosed in Patent Document <NUM> has such a problem that such reverse connection for removing blood through the blood return lumen provided in the distal end portion will result in recirculation in which blood returning from the blood removal lumen provided more proximal than the blood return lumen reenters the blood return lumen in the distal end portion. The same is true in reverse connection for two infusion lumens for supplying drug solution, and such reverse connection also causes similar recirculation.

It is an object of the present disclosure to provide a quadruple-lumen catheter in which recirculation of blood and a drug solution is difficult to occur even when the blood is removed through the blood return lumen for a reason such as resolving the sticking to the inner wall of the blood vessel, or an erroneous connection.

A quadruple-lumen catheter according to an aspect of the present disclosure A quadruple-lumen catheter, including: a cylindrical body extending from a proximal end to a distal end and being surrounded by an outer wall, the body having an inner space divided into a first region and a second region by a partition extending in a longitudinal direction, the first region being divided into a first lumen and a third lumen being smaller in cross-sectional area than the first lumen, the second region being divided into a second lumen and a fourth lumen being smaller in cross-sectional area than the second lumen, the third lumen and the fourth lumen facing each other with the partition interposed therebetween, the second lumen having a second opening plane at its distal end, and the first lumen having a first opening plane at its distal end, and the second opening plane being more distal than the first opening plane, the third lumen having a third opening plane at its distal end, and the third opening plane being more distal than the second opening plane, the fourth lumen having a fourth opening plane at its distal end, and the fourth opening plane being more distal than the third opening plane, and the partition being such that, between the distal end of the body and the second opening plane, a width of the partition is gradually narrowed toward the third lumen and the fourth lumen.

Such a configuration makes it difficult to cause recirculation of blood and a drug solution even when the blood is removed through the first lumen or the second lumen. Such a configuration further makes it easy to insert the catheter into a blood vessel, thereby making it difficult to damage the blood vessel. In such a configuration, the first lumen and the second lumen can be large in cross-sectional area. This can more effectively making it difficult that the blood vessel sticks to the first lumen or the second lumen even when blood is removed through the first lumen or the second lumen.

The quadruple-lumen catheter according to an aspect may be so configured that the first lumen and the second lumen are symmetrical with respect to the partition, and the third lumen and the fourth lumen are symmetrical with respect to the partition. Such a configuration makes it difficult to cause recirculation of blood and a drug solution. Further, each lumen is symmetrical with respect to the partition. This facilitates extrusion molding in manufacturing of the quadruple-lumen catheter.

The quadruple-lumen catheter according to an aspect may be configured such that the first opening plane and the second opening plane are identical in size. With such a configuration, even when the first lumen or the second lumen is used as a blood removal lumen, the amount of blood removed can be secured, and the suction pressure can be lowered to more effectively make it difficult that the inner wall of the blood vessel sticks to the first opening plane or the second opening plane.

The quadruple-lumen catheter according to an aspect may be so configured that the first opening plane, the second opening plane, and the third opening plane are inclined toward the proximal end of the body with respect to the partition, and the fourth opening plane is orthogonal to the partition. Such a configuration facilitates insertion of the quadruple-lumen catheter into a blood vessel, thereby making it difficult to damage the blood vessel.

The quadruple-lumen catheter according to an aspect may be configured such that a portion of the body between the distal end thereof and the second opening plane has a lower hardness than a portion of the body between the second opening plane and the proximal end. Such a configuration facilitates insertion of the quadruple-lumen catheter into a blood vessel, thereby making it further difficult to damage the blood vessel.

The quadruple-lumen catheter according to an aspect may include a plurality of branch pipes provided to the proximal end of the body, the plurality of branch pipes being connected respectively to the first lumen, the second lumen, the third lumen, and the fourth lumen and being each provided with a connector at a proximal end thereof. With such a configuration, hemodialysis can be performed by connecting between the body and a blood circuit and the like via the connectors.

The quadruple-lumen catheter according to an aspect may be configured such that the first lumen has a plurality of first lumen side pores in its distal end portion, and the second lumen has a plurality of second lumen side pores in its distal end portion. With such a configuration, even when the first lumen or the second lumen is used as a blood removal lumen, the suction pressure can be lowered to make it difficult that the inner wall of the blood vessel sticks to the first opening plane or the second opening plane. Further, the removal blood flow rate can be easily ensured.

The quadruple-lumen catheter according to an aspect may be such that the outer wall has, in a portion where the first lumen is provided, a first lumen slit notching a distal end of the outer wall and/or in a portion where the second lumen is provided, a second lumen slit notching the distal end. With such a configuration, even when the first lumen or the second lumen is used as a blood removal lumen, the suction pressure can be diffused to more effectively make it difficult that the inner wall of the blood vessel sticks to the first opening plane or the second opening plane. Further, the configuration allows to easily ensure the removal blood flow rate.

The invention is defined by claim <NUM> and further defined in dependent claims <NUM>-<NUM>.

According to the quadruple-lumen catheter of the present disclosure, recirculation is difficult even when blood is removed through the blood return lumen for a reason such as resolving the sticking to the inner wall of the blood vessel, or an erroneous connection.

A quadruple-lumen catheter of the present disclosure is for use in performing administration of drug solution, measurement of central venous pressure, or the like concurrently when performing blood purification by hemodialysis using a blood removal lumen and a blood return lumen. As illustrated in <FIG>, the quadruple-lumen catheter of the present disclosure includes: a cylindrical body (a catheter tube) <NUM> surrounded by an outer wall <NUM>. A partition <NUM> extending in a longitudinal direction is provided inside the body <NUM>. The partition <NUM> divides an inner space of the body <NUM> into a first region <NUM> and a second region <NUM>. The first region <NUM> is divided into a first lumen <NUM> and a third lumen <NUM>, and the second region <NUM> is divided into a second lumen <NUM> and a fourth lumen <NUM>. During normal forward connection, the first lumen <NUM> serves as a blood removal lumen, and the second lumen <NUM> serves as a blood return lumen. During a reverse connection in which the blood removal lumen and the blood return lumen are switched to solve sticking to the blood vessel wall, the first lumen <NUM> serves as a blood return lumen, and the second lumen <NUM> serves as a blood removal lumen. The third lumen <NUM> and the fourth lumen <NUM> serve as an infusion lumen to be used as routes for administration of drug solution, measurement of central venous pressure, or the like.

The third lumen <NUM> and the fourth lumen <NUM> are each circular in cross section, and the third lumen <NUM> and the fourth lumen <NUM>, being on one of sides where the outer wall <NUM> and the partition <NUM> are in contact with each other, are positioned to face each other with the partition <NUM> interposed therebetween. The first lumen <NUM> and the second lumen <NUM> are positioned to face each other with the partition <NUM> interposed therebetween. In such a configuration, the third lumen <NUM>, which serves as an infusion lumen, is provided in the first region <NUM>, and the fourth lumen <NUM>, which serves as the other infusion lumen, is provided in the second region <NUM>. This allows to have the first lumen <NUM> and the second lumen <NUM> with larger cross-sectional areas, while two infusion lumens are provided. Therefore, even when either the first lumen <NUM> or the second lumen <NUM> is used as the blood removal lumen, the amount of blood removed can be secured and the suction pressure can be lowered to make the sticking of the blood vessel difficult. Further, the first lumen <NUM> and the second lumen <NUM>, and the third lumen <NUM> and the fourth lumen <NUM> are symmetrically formed, in pair, with the partition <NUM> interposed therebetween. This facilitates extrusion molding for producing the quadruple-lumen catheter.

The distal ends of the first lumen <NUM>, the second lumen <NUM>, the third lumen <NUM>, and the fourth lumen <NUM> are of an end hole-type with an opening at the distal end, thereby forming a first opening plane <NUM>, a second opening plane <NUM>, a third opening plane <NUM>, and a fourth opening plane <NUM>, respectively. At the first opening plane <NUM>, the outer wall <NUM> is so trimmed that the outer wall <NUM> becomes farther from the partition <NUM> toward the proximal end. Thus, the first opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. The second opening plane <NUM> is provided more distally than the first opening plane <NUM>, and, at the second opening plane <NUM>, the outer wall <NUM> is so trimmed that the outer wall <NUM> becomes farther from the partition <NUM> toward the proximal end. Thus, the second opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. The third opening plane <NUM> is provided more distally than the second opening plane <NUM>, and, at the third opening plane <NUM>, the outer wall <NUM> is so trimmed that the outer wall <NUM> becomes farther from the partition <NUM> toward the proximal end. Thus, the third opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. The fourth opening plane <NUM> is provided more distally than the third opening plane <NUM>, and located at the distal end of the body <NUM>, and the fourth opening plane <NUM> is orthogonal to the partition <NUM>.

Although the use of the quadruple-lumen catheter of the present embodiment is not limited in terms of which direction is the upward, downward, rightward, or leftward direction of the quadruple-lumen catheter, the following description assumes that, with respect to the partition <NUM>, the upper side is the side on which the first region <NUM> provided with the first lumen <NUM>, and the lower side is the side on which a second region <NUM> provided with the third lumen <NUM> is located, and the right side is the side on which the first lumen <NUM> and the second lumen <NUM> are located, while the left side is the side on which the third lumen <NUM> and the fourth lumen <NUM> are located, when the body <NUM> is viewed from the distal end with the first region <NUM> on the upper side.

In the quadruple-lumen catheter of the present embodiment, the partition <NUM> is provided between the first lumen <NUM> and the second lumen <NUM>, and the partition <NUM> extends toward the distal end beyond the first opening plane <NUM> of the first lumen <NUM>. Thus, during the reverse connection, blood which returns through the first lumen <NUM> to flow above the partition <NUM> is less likely to be sucked via the second opening plane <NUM> below the partition <NUM>, thereby making it difficult for the recirculation to occur. The making it difficult to cause the recirculation is advantageous not only in the case where the reverse connection is intentionally performed to resolve the sticking to the blood vessel wall, but also in the case of erroneous reverse connection.

Moreover, the partition <NUM> extends toward the distal end of the body <NUM> beyond the position of the second opening plane <NUM>, and, from the position of the second opening plane <NUM> to the distal end, the partition <NUM> becomes narrower in width toward the left side on which the third lumen <NUM> and the fourth lumen <NUM> are disposed, and disappears at the distal end. This makes it easy to inset the catheter by the Seldinger technique or the like, and also makes the partition <NUM> less damaging to the blood vessel. In the present embodiment, the partition <NUM> has a width gradually narrowed toward the distal end from the position of the second opening plane <NUM>. However, in view of preventing recirculation, the partition <NUM> has a width gradually narrowed toward the distal end from somewhere between the second opening plane <NUM> and the distal end.

For the blood removal via the first lumen <NUM>, it is preferable that the first opening plane <NUM> be located as far away from the third opening plane <NUM> and the fourth opening plane <NUM> as possible for the sake of avoiding recirculation of the drug solution supplied through the third lumen <NUM> and the fourth lumen <NUM>. In view of the length of the catheter, it is preferable that the distance from the distal end of the body <NUM> be not too long. More specifically, a distance L1 from the distal end (the fourth opening plane <NUM>) of the body <NUM> to the first opening plane <NUM> is preferably <NUM> or longer, or more preferably <NUM> or longer, but preferably <NUM> or shorter, more preferably <NUM> or shorter, or yet more preferably <NUM> or shorter.

The first opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. The inclination of the first opening plane <NUM> toward the proximal end can reduce insertion resistance in intracorporeally inserting the catheter by the Seldinger technique or the like, whereby the insertion of the catheter can be smooth, as compared with the case where the first opening plane <NUM> is orthogonal to the partition <NUM>. Further, the inclination also makes the first opening plane <NUM> less damaging to the blood vessel. Further, the inclination gives the first opening plane <NUM> a larger size (a larger opening plane area) than that in the case where the first opening plane <NUM> is orthogonal to the partition <NUM>. This makes it easier to ensure the blood flow rate and lower of the suction pressure in removing the blood through the first lumen <NUM>.

To be less damaging to the blood vessel, the first opening plane <NUM> has an inclination angle θ1 that may be preferably <NUM>° or less, more preferably <NUM>° or less, or yet more preferably <NUM>° or less. On the other hand, for performing the blood removal through the first lumen <NUM> in such a way that the wall of the blood vessel is prevented from sticking to the first opening plane <NUM> due to the suction pressure caused by the blood removal and consequently closing the first opening plane <NUM>, the inclination angle θ1 may be preferably <NUM>° or more, or more preferably <NUM>° or more.

It is preferable that the second opening plane <NUM> be located as far away from the first opening plane <NUM> as possible in light of preventing recirculation between the first lumen <NUM> and the second lumen <NUM>. On the other hand, it is preferable that the second lumen <NUM> be located as far away from also the third opening plane <NUM> as possible in light of preventing recirculation between the second lumen <NUM> used as a blood removal lumen during reverse connection and the third lumen <NUM>. Thus, a distance L1 - L2 between the first opening plane <NUM> and the second opening plane <NUM> may be preferably <NUM>% or more, more preferably <NUM>% or more, and preferably <NUM>% or less, or more preferably <NUM>% or less of the distance L1 between the first opening plane <NUM> and the fourth opening plane <NUM>.

Similarly to the first opening plane <NUM>, the second opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. This reduces the insertion resistance in intracorporeally inserting the catheter by the Seldinger technique or the like, whereby the insertion of the catheter can be smooth, as compared with the case where the second opening plane <NUM> is orthogonal to the partition <NUM>. Further, the inclination makes the second opening plane <NUM> less damaging to the blood vessel. Further, the inclination gives the second opening plane <NUM> a larger size (a larger opening plane area) than that in the case where the second opening plane <NUM> is orthogonal to the partition <NUM>. This makes it easier to ensure the blood flow rate in removing the blood through the second lumen <NUM>, and allows lowering the suction pressure. The second opening plane <NUM> and the first opening plane <NUM> may be identical in size in consideration of using the second lumen <NUM> as a blood removal lumen.

An inclination angle θ2 of the second opening plane <NUM> may be preferably <NUM>° or less, more preferably <NUM>° or less, or yet more preferably <NUM>° or less. The inclination angle θ2 may be preferably <NUM>° or more, or more preferably <NUM>° or more in light of making it possible to remove blood through the second lumen <NUM>.

It is preferable that the third opening plane <NUM> be located as far away from the first opening plane <NUM> and the second opening plane <NUM> as possible in light of preventing recirculation between the first lumen <NUM> serving as a blood removal lumen during forward connection and the third lumen <NUM> and between the second lumen <NUM> serving as a blood removal lumen during reverse connection and the third lumen <NUM>. Thus, a distance L1 - L3 between the first opening plane <NUM> and the third opening plane <NUM> may be preferably <NUM>% or more, or more preferably <NUM>% or more, but preferably <NUM>% or less, or more preferably <NUM>% or less of the distance L1 between the first opening plane <NUM> and the fourth opening plane <NUM>. Moreover, a distance L2 - L3 between the second opening plane <NUM> and the third opening plane <NUM> may be preferably <NUM>% or more, or more preferably <NUM>% or more, but preferably <NUM>% or less, or more preferably <NUM>% or less of the distance L2 between the second opening plane <NUM> and the fourth opening plane <NUM>.

Similarly to the first opening plane <NUM> and the second opening plane <NUM>, the third opening plane <NUM> is inclined toward the proximal end with respect to the partition <NUM>. This reduces the insertion resistance in intracorporeally inserting the catheter into the subject's body by the Seldinger technique or the like, whereby the insertion of the catheter can smooth, as compared with the case where the third opening plane <NUM> is orthogonal to the partition <NUM>. Further, the inclination makes third opening plane <NUM> less damaging to the blood vessel. The inclination angle θ3 of the third opening plane <NUM> may be preferably <NUM>° or less, more preferably <NUM>° or less, or yet more preferably <NUM>° or less. The inclination angle θ1 of the first opening plane <NUM>, the inclination angle θ2 of the second opening plane <NUM>, and the inclination angle θ3 of the third opening plane <NUM> may be identical to or different from one another.

The fourth lumen <NUM> has a circular cross-sectional outer shape at the distal end of the body <NUM>. This makes the fourth lumen <NUM> less damaging to the blood vessel, as compared with the case where the fourth lumen <NUM> has an angular cross-sectional outer shape. The fourth lumen <NUM> has such an outer diameter between the distal end and the third opening plane <NUM> that may be preferably <NUM> or greater, or more preferably <NUM> or greater, but preferably <NUM> or smaller, or more preferably <NUM> or smaller in light of the ease insertion of the catheter.

In the quadruple-lumen catheter of the present embodiment, the third opening plane <NUM> and the fourth opening plane <NUM> are located more distally than the second opening plane <NUM>. Accordingly, when the second lumen <NUM> serves as a blood return lumen during the forward connection, a drug solution supplied through the third lumen <NUM> and the fourth lumen <NUM> is carried by the blood flow through the blood vessel and blood flowing out of the second opening plane <NUM>, and flows away from the first opening plane <NUM> through which blood is removed. This makes it difficult to cause recirculation of the drug solution. On the other hand, even when the second lumen <NUM> in the second region <NUM> serves as a blood removal lumen during the reverse connection, the location of the third opening plane <NUM> being in the first region <NUM> which is on the opposite side to the second region <NUM> across the partition <NUM> results in that a drug solution supplied through the third lumen <NUM> is carried by the blood flow flowing out of the first opening plane <NUM>, and flows away from the second opening plane <NUM> through which blood is removed. This makes it difficult to cause recirculation of the drug solution. Further, the fourth opening plane <NUM> is located at the distal end of the body <NUM>. Thus, even when the second lumen <NUM> serves as a blood removal lumen during the reverse connection, the drug solution supplied through the fourth lumen <NUM> is carried by the blood flow through the blood vessel and the blood flow flowing out of the first opening plane <NUM> and through the first region <NUM>, and flows away from the second opening plane <NUM> through which blood is removed. This makes it difficult to cause recirculation of the drug solution.

In the quadruple-lumen catheter according to the present embodiment, the third lumen <NUM> and the fourth lumen <NUM> are provided in the vicinity of a portion where the outer wall <NUM> of the body <NUM> and the partition <NUM> are in contact with each other, in such a way that the third lumen <NUM> and the fourth lumen <NUM> face each other with the partition <NUM> interposed therebetween, and are disposed on one side (the left side) of the body <NUM>. This makes it possible to provide the third opening plane <NUM> at a position more distal than the second opening plane <NUM>, while gradually narrowing the width of a portion of the partition <NUM> from the second opening plane <NUM> toward the distal end. Thus, the quadruple-lumen catheter can be easily inserted into the blood vessel. The second opening plane <NUM> and the third opening plane <NUM> are arranged on opposite sides with respect to the central axis of the body <NUM>, thereby being distanced from each other. Thus, recirculation is less likely to occur even in reverse connection. If the third lumen <NUM> and the fourth lumen <NUM> are arranged opposite sides with respect to the central axis of the body <NUM>, it is necessary to separate the second opening plane <NUM> and the third opening plane <NUM> from each other by the partition <NUM> in order to prevent recirculation during reverse connection. Thus, the third opening plane <NUM> cannot be provided closer to the distal end than the second opening plane <NUM>, while gradually narrowing the width of a portion of the partition <NUM> from the second opening plane <NUM> toward the distal end.

When blood is removed through the first lumen <NUM> and returns through the second lumen <NUM>, the cross-sectional area of the first lumen <NUM> is preferably as large as possible to easily ensure the blood flow rate. However, in light of making it possible to remove blood also through the second lumen <NUM>, the ratio of the cross-sectional area of the second lumen <NUM> to the cross-sectional area of the first lumen <NUM> may be preferably <NUM> or more, or more preferably <NUM> or more. The ratio of the cross-sectional area of the second lumen <NUM> to the cross-sectional area of the first lumen <NUM> may be <NUM>, but may be preferably <NUM> or less, or more preferably <NUM> or less in light of ensuring the rate of blood removed through the first lumen <NUM>. The cross-sectional area of the first region <NUM> and the cross-sectional area of the second region <NUM> into which the inside of the body <NUM> is divided by the partition <NUM> may be identical with each other, but the cross-sectional area of the first region <NUM> may be larger than the cross-sectional area of the second region <NUM> in light of increasing the cross-sectional area of the first lumen <NUM>.

The cross-sectional areas of the first lumen <NUM> and the second lumen <NUM> and the sizes (the areas of the opening plane) of the first opening plane <NUM> and the second opening plane <NUM> may be such that the cross-sectional areas of the first lumen <NUM> and the second lumen <NUM> differ from each other, while the sizes of the first opening plane <NUM> and the second opening plane <NUM> are identical with each other. As an alternative, these may be so configured that the cross-sectional areas of the first lumen <NUM> and the second lumen <NUM> are identical with each other, while the sizes of the first opening plane <NUM> and the second opening plane <NUM> are identical with each other.

It is preferable that the first lumen <NUM> have such a cross-sectional area that is as large as possible in a portion of the first region <NUM> where the third lumen <NUM> is not present. Thus, the first lumen <NUM> may have a cross section other than a circular cross section. For example, the cross-sectional shape of the first lumen <NUM> may be a substantially circular shape such as an elliptical shape, a sector shape, or shapes distorted therefrom, in accordance with the shape of the portion of the first region <NUM> where the third lumen <NUM> is not present. Similarly, it is preferable that the second lumen <NUM> has such a cross-sectional area that is as large as possible in a portion of the second region <NUM> where the fourth lumen <NUM> is not present. Therefore, the second lumen <NUM> may have a substantially circular cross section in accordance with the shape of the portion of the second region <NUM> where the fourth lumen <NUM> is not present. The configuration in which the first lumen <NUM> and the second lumen <NUM> each are substantially circular in cross section can provide efficient utilization of the lumen of the body <NUM>, and allows both the first lumen <NUM> and the second lumen <NUM> to be large in cross-sectional area. At least either one of the first lumen <NUM> or the second lumen <NUM> may have a circular cross section.

On the other hands, because the third lumen <NUM> and the fourth lumen <NUM> which each serve as an infusion lumen do not require a large flow rate, the cross-sectional areas of the third lumen <NUM> and the fourth lumen <NUM> are smaller than the cross-sectional areas of the first lumen <NUM> and the second lumen <NUM>, and may be preferably <NUM> or more, more preferably <NUM> or more, and preferably <NUM> or less, more preferably <NUM> or less. The cross-sectional areas of the third lumen <NUM> and the fourth lumen <NUM> may be identical from each other, but the ratio of the cross-sectional area of the third lumen <NUM> to the cross-sectional area of the fourth lumen <NUM> may be changed within the range of about <NUM> to about <NUM> according to the intended use of each lumen.

The configuration in which the third lumen <NUM> and the fourth lumen <NUM> are each circular in cross section can reduce the resistance of fluid, thereby facilitating pumping, and also makes it easy to form the third lumen <NUM> and the fourth lumen <NUM>. However, the third lumen <NUM> and the fourth lumen <NUM> may not be circular in cross section, and may be substantially circular in cross section.

The distal end portion of the first lumen <NUM> may be provided with a first lumen side pore <NUM> or first lumen side pores <NUM> communicating between the first lumen <NUM> and the outside. This configuration can reduce the suction pressure at the first opening plane <NUM> when the first lumen <NUM> serves as a blood removal lumen, thereby preventing the inner wall of the blood vessel from sticking to the first opening plane <NUM>. Further, this configuration makes is possible to easily ensure the removal blood flow rate.

It is preferable to provide a plurality of the first lumen side pores <NUM> in order to attain a greater effect of dispersing the suction pressure. The number of first lumen side pores <NUM> is not particularly limited, but it is preferable to provide two first lumen side pores <NUM> each on an upper side and a right side of the first lumen <NUM>. However, the first lumen side pores <NUM> may be provided as needed and may be omitted.

The distal end portion of the second lumen <NUM> may be provided with a second lumen side pore <NUM> or second lumen side pores <NUM> communicating between the second lumen <NUM> and the outside. This configuration can reduce the suction pressure at the second opening plane <NUM> when the second lumen <NUM> serves as a blood removal lumen, thereby preventing the inner wall of the blood vessel from sticking to the second opening plane <NUM>. Further, this configuration makes it possible to easily ensure the removal blood flow rate.

It is preferable to provide a plurality of the second lumen side pores <NUM> in order to attain a greater effect of dispersing the suction pressure. The number of second lumen side pores <NUM> is not particularly limited, but it is preferable to provide two second lumens <NUM> each on an upper side and a right side of the second lumen <NUM>. However, the second lumen side pores <NUM> may be provided as needed and may be omitted.

The length of the body <NUM> is not particularly limited, but may be preferably <NUM> or longer, or more preferably <NUM> or longer, but preferably <NUM> or shorter, or more preferably <NUM> or shorter.

The outer diameter of the body <NUM> is not particularly limited, but may be preferably <NUM> or greater, or more preferably <NUM> or greater in light of ensuring the blood flow rate. Moreover, for being insertable into the blood vessel, the outer diameter of the body <NUM> may be preferably <NUM> or smaller, or more preferably <NUM> or smaller.

The thickness of the outer wall <NUM> of the body <NUM> is not particularly limited, but is preferably <NUM> or more, more preferably <NUM> or more, and preferably <NUM> or less, more preferably <NUM> or less in light of the strength and flexibility of the catheter.

The body <NUM> may be formed of a material which is hard enough to maintain a stable shape in the blood vessel and but soft enough not to damage the blood vessel, such as polyurethane, polyvinyl chloride, silicone, polyethylene, polypropylene, an ethylene-vinyl acetate copolymer, or a polyamide. The material of the body <NUM> is particularly preferably polyurethane, which maintains such a hardness that does not impair the ease of insertion of the catheter and becomes harder at normal temperatures and softer at internal body temperatures. A distal end portion of the body <NUM>, e.g., a portion of the body <NUM> between the distal end and the second opening plane <NUM> may be configured to be less damaging to blood vessels by being softer than the rest of the body <NUM>. At least a portion of the body <NUM> may be formed of a material containing a contrast agent such as barium sulfate, bismuth tungstate, or bismuth oxide, so as to facilitate finding out where the body <NUM> is inserted. For example, by configuring such that the distal end of the body <NUM> has a color different from the color of the other portion of the body <NUM>, the position of the distal end portion of the body <NUM> can be easily recognizable.

The body <NUM> is provided with branch pipes 103A to 103D extending from the proximal end of the body <NUM> via a branch portion <NUM>. Distal ends of the branch pipes 103A to 103D are connected to the first lumen <NUM> to the fourth lumen <NUM>, respectively. Each of the proximal ends of the branch pipes 103A to 103D is provided with a connector (not shown) connected thereto. The connectors, which are covered respectively with protection caps 131A to 131D in the illustrations in <FIG>, allow the body <NUM> to be connected to a blood circuit and the like via the connectors. The branch pipes 103A to 103D are provided respectively with clamps 132A to 132D attached thereto. With the clamps 132A to 132D, the branch pipes 103A to 103D can be closable for performing a treatment such as heparin rock.

The quadruple-lumen catheter of the present embodiment may be biocompatible-treated on at least one of an inner surface or an outer surface thereof with a biocompatible treatment of various types. For example, the quadruple-lumen catheter of the present embodiment may be antithrombotic-surfaced so as to prevent thrombus formation due to contact with blood during indwelling. The antithrombotic surfacing is not particularly limited and may be carried out by any methods such as a method of immobilizing a plasminogen activator such as urokinase or a method of immobilizing an anticoagulant such as heparin.

The catheter according to the present embodiment can be modified in various ways. In the following variations, only portions different from the present embodiment will be described. The description of the configuration common to the present embodiment will be omitted as appropriate. In addition, like portions are denoted with like reference numerals as in the present embodiment.

As a variation of the catheter according to the present embodiment, as shown in <FIG>, a first lumen slit <NUM> notching a portion of the distal end may be provided in a portion of the outer wall <NUM> where the first lumen <NUM> is provided. Further, a second lumen slit <NUM> notching a portion of the distal end may be provided in a portion of the outer wall <NUM> where the second lumen <NUM> is provided.

With such a configuration, the flow of blood sucked into the first lumen <NUM> is dispersed also into the first lumen slit <NUM> during forward connection. This reduces the suction pressure, thereby making it difficult to cause sticking to the blood vessel wall. With this configuration, even if the first opening plane <NUM> is clogged due to thrombus or the like, the first lumen <NUM> can be kept open. Further, with the second lumen slit <NUM>, the same effect as in the configuration with the first lumen slit <NUM> can be obtained during the reverse connection.

Moreover, the body <NUM> may be so configured that the distal end portion of the body <NUM>, e.g., a portion of the outer wall <NUM> between the distal end and a proximal end of the first lumen slit <NUM> is softer than the rest of the body <NUM> excluding the distal end portion. The configuration in which the first lumen slit <NUM> and the second lumen slit <NUM> notching portions of the distal end of the outer wall <NUM> are provided makes the outer wall <NUM> more easily deformable, but the configuration in which the distal end portion of the outer wall <NUM> is softer makes the outer wall <NUM> even more easily deformable. These configurations bring about such an effect that, when the catheter is inserted, the outer walls <NUM> forming the first lumen <NUM> and the second lumen <NUM> are easily deformed by bending inwardly toward the inside of the first lumen <NUM> and the inside of the second lumen <NUM>. This provides such an excellent insertability to the catheter that, at inserting the catheter, the cross-sectional areas of the body <NUM> at the first opening plane <NUM> and the second opening plane <NUM> become smaller, thereby avoiding a sudden increase in insertion resistance.

The length L4 of the first lumen slit <NUM> and the length L5 of the second lumen slit <NUM> are not particularly limited, but may be preferably <NUM> or more but <NUM> or less, or more preferably <NUM> or more but <NUM> or less in light of reducing sticking of the catheter to the blood vessel wall. The length L4 of the first lumen slit <NUM> and the length L5 of the second lumen slit <NUM> may be identical to or different from each other.

It is sufficient that the widths of the first lumen slit <NUM> and the second lumen slit <NUM> are as predetermined. The widths of the first lumen slit <NUM> and the second lumen slit <NUM> are not particularly limited, and may be preferably <NUM> or more but <NUM> or less, or more preferably <NUM> or more but <NUM> or less in light of ensuring rigidity of the outer wall <NUM>. The widths of the first lumen slit <NUM> and the second lumen slit <NUM> may be identical to or different from each other.

The first lumen slit <NUM> and the second lumen slit <NUM> illustrated in <FIG> each are constant in width in the longitudinal direction, but the width is not limited to this, and the width may change in the longitudinal direction. For example, the first lumen slit <NUM> or the second lumen slit <NUM> may become wider gradually from its distal end to its proximal end.

Although the above discusses a variation in which the quadruple-lumen catheter is configured with the first lumen slit <NUM> and the second lumen slit <NUM>, but the quadruple-lumen catheter may be configured with either the first lumen slit <NUM> or the second lumen slit <NUM>.

Claim 1:
A quadruple-lumen catheter, comprising:
a cylindrical body (<NUM>) extending from a proximal end to a distal end and being surrounded by an outer wall (<NUM>),
the body (<NUM>) having an inner space divided into a first region (<NUM>) and a second region (<NUM>) by a partition (<NUM>) extending in a longitudinal direction,
the first region (<NUM>) being divided into a first lumen (<NUM>) and a third lumen (<NUM>) being smaller in cross-sectional area than the first lumen (<NUM>),
the second region (<NUM>) being divided into a second lumen (<NUM>) and a fourth lumen (<NUM>) being smaller in cross-sectional area than the second lumen (<NUM>), characterized in that
the third lumen (<NUM>) and the fourth lumen (<NUM>) face each other with the partition (<NUM>) interposed therebetween,
the second lumen (<NUM>) has a second opening plane (<NUM>) at its distal end, and the first lumen (<NUM>) has a first opening plane (<NUM>) at its distal end, the second opening plane (<NUM>) being more distal than the first opening plane (<NUM>),
the third lumen (<NUM>) has a third opening plane (<NUM>) at its distal end, the third opening plane (<NUM>) being more distal than the second opening plane (<NUM>),
the fourth lumen (<NUM>) has a fourth opening plane (<NUM>) at its distal end, the fourth opening plane (<NUM>) being more distal than the third opening plane (<NUM>), and
the partition (<NUM>) is such that, between the distal end of the body (<NUM>) and the second opening plane (<NUM>), a width of the partition (<NUM>) is gradually narrowed toward the third lumen (<NUM>) and the fourth lumen (<NUM>).