The invention relates to a drainage tube for use in wound drainage, in particular in deep drainage, having a drainage lumen surrounded by a tube jacket and extending parallel to the tube axis, as well as a treatment kit equipped with such a drainage tube.

Drainage tubes are required in wound care for draining wound fluid, in particular exudates, i.e. inflammation-related discharges from the wound.

In some cases, in order to promote wound drainage and the overall wound healing process, a negative pressure is also generated in the area of the wound. For this purpose,

the drainage lumen of a drainage tube may be connected to a device for generating a negative pressure, such as a pump, on the side facing away from the wound. In this case, the wound space is usually closed off by way of an occlusive film, in order to counteract any pressure compensation in the wound space. At the same time, to promote drainage, aeration of the wound space may also be provided in the drainage lumen in order to maintain a flow draining off the wound fluid. In particular in the treatment of deep-seated wounds, hence in deep drainage, it has been shown that only insufficient drainage of the wound fluid from the wound space is achieved, even if a negative pressure and possibly also flow-promoting aeration are used.

In view of these problems in the state-of-the-art, the invention is based on the object of providing a drainage tube by means of which wound drainage can be assured even in the case of deep-seated wounds.

According to the invention, this object is achieved by an enhancement of the prior art drainage tubes, which is essentially characterized in that the tube jacket has at least one perforation, which, starting at an outer boundary area of the tube jacket, extends in a transverse direction, in particular approximately perpendicular to the tube axis and opens out into the drainage lumen.

Using drainage tubes enhanced according to the invention, the aspiration of wound fluid, in particular of exudates, can take place over a larger area, i.e. the frontal opening area of the drainage lumen and the opening area of the perforation in the area of the outer boundary area of the drainage tube. This assures that even in the case of deep-seated wounds, in which large-area aspiration is required, satisfactory drainage of the wound fluid takes place.

Within the scope of the invention, the improvement of wound drainage in the case of deep-seated wounds can even be achieved using only one perforation of the tube jacket. It has, however, proven to be particularly advantageous if the tube jacket has at least one drainage section of a given length, for example approx. 300 mm, with two, three or a plurality of perforations opening out into the drainage lumen and a line section without any perforation, wherein the axial length of said line section without any perforation is longer than the axial distance between said perforations in said drainage section.

Homogeneous drainage of wound fluids can take place if the perforations are arranged at invariable axial distances from each other. For this purpose, 15 to 25 perforations having axial distances of 5 mm to 20 mm may be provided. This results in a total length of the perforation section of 75 mm to 500 mm. In general, it suffices if the perforation section has a length of 250 mm to 350 mm, in particular approx. 300 mm. The line section may have a length of 400 mm to 700 mm, in particular 500 mm to 650 mm, particularly preferred approx. 600 mm.

For the purpose of aerating the wound space, the tube jacket may also, in addition to the drainage lumen, be penetrated by at least one aeration lumen, which is arranged radially offset thereto and preferably also extends approximately parallel to the tube axis and which is, at least in sections, separated from the drainage lumen by a tube jacket area situated radially inside and has a radial thickness of preferably 0.2 mm to 0.7 mm, in particular at least 0.4 mm. As a result of this arrangement, drainage and aeration of the wound can take place using only one multilumen tube.

In order to assure reliable aeration of the wound, within the scope of the invention, it has proven to be particularly expedient if the tubular jacket is penetrated by two, three or a plurality of aeration lumens, which penetrate the tube jacket and are offset against each other in the circumferential direction of the tube jacket. In this and other embodiments of the invention, the drainage lumen may extend coaxial to the tube axis, while the axes of the aeration lumens are arranged in a radial intersecting plane on a circular line encircling the tube axis. In this case, the aeration lumens are radially offset at equal intervals with respect to the exudate lumen.

The creation of the perforation connecting the tube jacket to the drainage lumen for providing large-area aspiration will be facilitated if the offset between two adjacent aeration lumens in the circumferential direction is larger than 360°/n, where n denotes the number of aeration lumens. The perforation for creating an additional drainage port then takes place in the area between the aeration lumens, which are particularly strongly offset against each other, in order to reduce thereby the risk of any accidental damage to an aeration lumen. Related thereto, it has proven to be particularly expedient if the offset between two adjacent aeration lumens in the circumferential direction of the drainage tube is in the range between 120° and 240°, preferably between 150° and 210°, in particular between 170° and 190°.

Within the scope of the invention, it is particularly preferred if the drainage tube has three aeration lumens. For this purpose, a particularly large distance between two aeration lumens can be created subject to geometrically easily producible conditions if the longitudinal axes of two aeration lumens are situated on a common radial line of the tube and the axis of the drainage lumen. Between two aeration lumens, a tube jacket area is then provided, which extends over a circumferential angle of 180° and is available for creating a perforation, while, on the other hand, an additional aeration lumen can be made available in the remaining circumferential section. If, in the last-described embodiment of the invention, the longitudinal axis of the aeration lumens in a radial intersecting plane form the vertices of a right triangle, while, at the same time, making sure that the longitudinal axis of the aeration lumens are situated on a circular line encircling the tube axis, continuous perforation of the tube having a particularly large perforation radius can take place without any damage to the aeration lumens.

In this respect, it has proven to be particularly expedient if at least one, preferably all, aeration lumens in a radial intersecting plane have a smaller sectional area than the drainage lumen.

It is equivalent to the arrangement of the axes of the aeration lumens on a circular line encircling the tube axis if the aeration lumens have approximately the same radial distances from the longitudinal axis of the drainage lumen, provided the drainage lumen per se is coaxial with the tube axis.

A further improvement of the drainage of wound fluid, in particular of exudates, can be achieved if the aeration of the wound does not take place at only one face of the drainage tube, but if the tube jacket has at least one aeration perforation, which, starting at an outer boundary area of the tube jacket, extends in a transverse direction, in particular approximately perpendicular to the tube axis and opens out into at least one aeration lumen. Aeration of the wound space across this aeration perforation can, additionally or alternatively, take place via frontal openings of the aeration lumens. As the case may be, these frontal openings must be closed or caused to be closed.

The aeration lumens may also be arranged distributed over a given axial length of the drainage tube. For this purpose, the tube jacket has at least one aeration section of a given length having two, three or a plurality of aeration perforations that open out into at least one aeration lumen as well as a line section without any perforation, wherein the axial length of said line section without any perforation is longer than the axial distance between said perforations in said drainage section.

Within the scope of the invention, aeration section and drainage section may, at least in parts, overlap or even coincide in the axial direction. In terms of manufacturing technology and for the purpose of effective aeration of the wound, it has proven to be expedient if at least one aeration perforation penetrates an aerating lumen, preferably in the radial direction, and opens out into a drainage lumen.

In the interest of effective wound monitoring, it has proven to be expedient if the drainage tube is equipped with an X-ray contrast strip extending in the longitudinal direction of the tube. In a particularly preferred embodiment of the invention, in this arrangement, this X-ray contrast strip may extend in the axial direction in a jacket area without any aeration lumen, preferably in the jacket area of the drainage tube, which is arranged between the aeration lumens that are particularly far apart from each other in the circumferential direction. As a result, the X-ray contrast strip simultaneously forms a marking for the location, at which the perforation of the tube jacket can be implemented in a particularly easy manner without any damage to any aeration lumen.

In all the embodiments of the invention, the drainage tube is preferably made of silicone having a Shore hardness of preferably approx. 50 A. In this case, the tube can receive a so-called “LowTack” surface treatment to reduce the surface roughness. An additional coating (e.g., Parylene) for reducing the surface roughness/tack/gas permeability is also possible, but only required in a few cases. According to all the embodiments of the invention, the drainage tube may have an outside diameter of 6 mm to 10 mm, preferably approx. 8 mm. In all the embodiments of the invention, the cross-section of the exudate lumen is approximately 3 mm to 4 mm, preferably approximately 3.9 mm, The aeration lumens may have a diameter of approx. 0.5 mm to 1.5 mm, preferably approx. 1 mm. The perforations opening out into the exudate lumen, may, just like the aeration perforations, have a diameter of 2 mm to 4 mm, preferably approx. 2.8 mm.

In all the embodiments of the invention, the X-ray contrast strip may contain barium sulfate (approx. 40%). The silicone to be used within the scope of the invention is preferably gas-tight. For this purpose, care is taken to assure that the system does not lose more than 5 mm Hg at 200 Hg initial pressure within 7.5 minutes.

The special utility of a drainage tube according to the invention was explained above related to deep drainage. But a drainage tube according to the invention can also be successfully used in planar drainage. It can then be expedient for the drainage tube in the area of the surface of the wound to be treated or the wound covering to extend, at least in sections, in arcuate form. It may be designed annular, helical and/or spirally.

In this respect, it has proven to be particularly expedient if, at least in sections, the drainage tube is made of a material having a Shore hardness in the range between 40 A and 60 A. It may, for instance, be made of silicone. If the Shore hardness is less than 40 A, the tube will be so soft that it tends to kink, thus blocking the exudate lumen and/or one or a plurality of aeration lumens. When using tubes having a Shore hardness of more than 60 A, the placement of the tube extending in arcuate form is problematic because, in that case, the restoring forces counteracting the tube bend may cause detachment of the tube from the wound or the wound packing material.

