WOUND DRAINAGE

Abstract: Wound drainage which comprises a cylinder (10) arranged as a suction chamber, with a piston (17) displaceable therein. The cylinder is capable of being connected via a stop-valve (13) to a drainage catheter (15) at one end thereof, whilst an elastic strand (19) which is connected with the piston is withdrawn through the other end of the cylinder. The strand can be locked in the desired withdrawn position by means of a locking device (23) which prevents the movement of the strand into the cylinder.

Description: WOUND DRAINAGE The invention relates to a wound drainage compris¬ ing a suction chamber, expandable under spring bias, for connection to a drainage catheter. Such wound drainages are used for the continuous removal of secretions which can collect in wounds after surgical operations. In known wound drainages of the type referred to, the suction chamber comprises a bellows which, when the wound drainage is to be applied, is compressed against the inherent spring bias of the bellows and is then left to expand slowly, causing a vacuum in the bellows and sucking in the secretion through the drainage catheter. At one end the bellows have a hose for connec¬ tion to the drainage catheter and at the other. end a hose for emptying the bellows of air or secretions which have collected therein, and the passage through both of these hoses can be closed off by means of a hose clamp. When air has been emptied from the bellows by the bellows being pressed together, whereby the air has to leave through either of the hoses, both hose clamps are engaged and the bellows are then connected with the drainage catheter. The co-nnection with the drainage catheter is then opened so that suction is exerted in the drainage catheter when the bellows try to expand as a result of their inherent spring bias. Emptying is undertaken by closing the passage to the drainage catheter, whilst the passage through the other hose on the bellows is opened, whereupon the bellows are compressed and the collected secretion is forced out through said 1 atter,-hose. A wound drainage of this known type is difficult to use and furthermore does not represent a closed system, so that there is ve ry considerable risk of the spread of infection to the surroundings when handling the wound drainage. Another known wound drainage comprises a vessel , normally a vacuum-moulded bottle or container with a ' hand-operated vacuum pump connected thereto. Before connecting the container to the drainage catheter, a certain vacuum can be brought about in the .contai ner by means of the vacuum pump, but as there can sub¬ sequently be a shock-like suction action on connection to the drainage catheter, which is not only uncomfort¬ able for the patient but can also be painful because of body tissue being sucked towards the inlet apertures of the drainage catheter, it is sometimes preferred to evacuate the container to a suitable vacuum when the wound drainage is applied. In such a case, however, it is necessary to have sterile filters in the evacuation line and this results in the wound drainage becoming much more expensive. Furthermore, emptying of the con¬ tainer invol ves ' problems as regards the spread of bacteria to the surroundings. The object of the present invention is to provide a wound drainage of the type initially referred to comprising a suction chamber, expandable under spring bias, for connection to a drainage catheter, which is easy to bring into the operational state before it has to be applied to the patient, and which gives a mild suction action which does not cause the patient any discomfort. Furthermore, it is intended to provide by the invention a wound drainage of this type which is designed as a closed system so as to prevent the spread of bacteria to the surroundings when handling the wound drainage. To satisfy the objects mentioned above the wound drainage in accordance with the invention has obtained the characteristics according to claim 1. OV:?! Such a wound drainage is ve ry suitable for manufacture as a throw-away article at relatively low price, whereby the most stringent hygienic requirements can be satisfied. Furthermore, with the wound drainage in accordance with the invention it is possible to adapt in a simple manner the suction action imposed in the wound drainage to suit the conditions under which the wound drainage is to ba employed. To illustrate the invention one embodiment thereof will be described in greater detail with reference to the attached drawing in which FIG. 1 is a perspective view of the wound drainage in accordance with the invention, and FIG. 2 is an axial sectional view, partially a side view, of the wound drainage in FIG. 1. The wound drainage illustrated in the drawing comprises a cylinder 10 which is preferably made from transparent plastic material. At one end, the cylinder is formed integrally with an end wall 11 which is pro- vided with a socket 12 for connection of a slide valve 13 of the embodiment described in the international application PCT/SE80/00019. The slide valve is designed to interact with a coupling element 14, also designed in accordance with said international application, and this coupling element is located on a drainage catheter 15 which is designed to be inserted into a wound and which has inlet apertures 16 for sucking up secretions from the wound through the catheter. In the cy inder 10 a piston 17 is displaceable and this piston has sealing rings 18 to provide a seal against the inside of the cylinder wall . A rubber string 19 is fastened in an eye 20 on the piston 17 and is drawn out from the cylinder through a socket 21 on one end wall 22 which is located as a cover on the other end of the cylinder 10. In the socket 21 the rubber string 19 passes between a " pair of clamping members 23 in the form of rollers or wedges, which permit the rubber string to be drawn out from the cylinder 10 through the socket 21 but which on the other hand lock the rubber string firmly to prevent movement into the cyl i nde . A thin tube-shaped plastics foil 24 is fastened at one end to the piston 17 and at the other end to the end wall 22 arranged as a cover. When the wound drainage is to be applied, the piston 17 should be located close to the end wall 11, as shown in the drawing, and the slide valve 13 must be in the closed position. The rubber string 19 is tensioned by being drawn out to a certain extent through the socket 21, the piston being prevented from moving under the influence of the rubber string by virtue of the vacuum which forms between the piston and the end wall 11 when the slide valve 13 is closed. Dependent on how much of the rubber string 19 is drawn out through the socket 21, i.e. dependent on the extent to which the rubber string is extended, a larger or smaller force is exerted on the piston. This force governs the suction action in the wound drainage. The rubber string is prevented from returning into the cylinder by the clamping members 23. After a force has been applied to the piston 17, in the manner described above, by tensioning the rubber string 19, the coupling element 14 on the drainage catheter 15 which has been placed in the wound, is connected with the slide valve 13 in the manner which has been described in detail in said international application. The piston 17, under the influence of the force in the tensioned rubber string 19, is now dis¬ placed in the cylinder 10, sucking in wound secretions via the catheter 15 and the open slide valve 13 into the cylinder 10. The piston moves smoothly and softly in the cylinder under the influence of the rubber string, so that a uniform suction is exerted in the catheter 15 without risk of discomfort or pain on the part of the patient. If required during the use of the wound drainage, the suction action can be easily increased by drawing out the rubber string 19 still further. Thanks to the provision of the tubular plastics foil 24, the rubber string 19 is completely separated from the cylindrical space between the piston 17 and the end wall 11 which is being filled with wound secretions, so that bacteria from the wound secretions cannot come out from the cylinder via the rubber string 19 through the socket 21. As described in detail in said internat •i*•on*al application, the drainage catheter 15 can be connected to or disconnected from the cylinder 10 by means of the slide valve 13 and the coupling element 14 without any risk whatever that the secretions which pass through the drainage catheter into the cylinder will emerge at the coupling point. On the other hand, the plastics foil 24 also prevents secretions which might possibly be able to ooze past the piston 17 emerging from the cylinder via the rubber string 19 and socket 21. Thus, it can be seen that the wound drainage forms a completely closed system which absolutely prevents the spread of bacteria or contamination to the surroundings. Just as important is the fact that by virtue of the use of the slide valve 13 and the coupling element 14, the migra¬ tion of bacteria is prevented from the surroundings via the coupling element 14 and the catheter 15 to the wound which is being drained. When the cylinder 10 has become filled with secretions to the extent permitted by the tension of the rubber string 19, the cylinder 10 is disconnecte from the drainage catheter 15 and, since the wound drainage is of simple and cheap design, it can then be thrown away. Thus, it is not necessary to empty the wound drainage, with the hygienic risks which ar connected therewith. A new wound drainage is connect to the drainage catheter 15 in the manner described • previousl . The embodiment described of the wound drainage accordance with the invention can be modified within •the scope of the appended claims. Thus, the piston 1 which in the embodiment described here is relatively thick and provided with sealing rings 18, can be rep by a relatively thin disc and it is also possible to replace the rubber string 19 e.g. by a helical sprin which can be extended and tensioned in the same way the rubber string. Other connecting devices between the drainage catheter and the cylinder are feasible, but the arrangement in accordance with said interna- tional application is to be preferred, because when using this arrangement an absolutely sealed system i obtained. Finally, it should be mentioned that by suitabl choice of the material for the rubber string and its dimensions it is possible to achieve a spring rate o the rubber string such that the suction action in th wound drainage remains fairly constant throughout th major portion of the movement of the piston in the cylinder. Furthermore, the extended portion of the rubber string can be employed for hanging up the wou drainage during use. However, even a simple rubber band can be employed. Furthermore, the elastic stran whether this be a rubber string, a rubber band, or a helical spring, can be provided with graduations so that it is easily possible to adjust the strand to the desired bias, i.e. a predetermined collected amount of wound secretions.

Claims: CLAIMS . - 1. Wound drainage comprising a suction chamber (10) expandable under spring bias for connection to a drainage catheter (15), c h a r a c t e r i z e d in that a cylinder (10) forming the suction chamber, with a piston 17 displaceable therein can be connected via a stop valve (13) to the drainage catheter (15) at one end, whilst an elastic strand (19) connected with the piston is pulled out through the other end of the cylinder and can be locked in the desired extended position by means of a locking device (23) which pre¬ vents movement thereof into the cylinder. 2. Wound drainage according to claim 1 , c h a r a c t e r i z e d in that the elastic strand (19) comprises a rubber string .or a rubber band. 3. Wound drainage according to claim 1 ^ o 2, c h a r a c t e r i z e d in that a tubular plastics foil (24) is arranged inside the cylinder (10), one end of which is fastened to the piston (17) and the other end of which is fastened to the cylinder at the said other end thereof, the tubular plastics foil sur- ' roundi n<f the elastic strand (19). 4. Wound drainage according to claim 3, c h a r a c t e r i z e d in that the tubular plastics foil (24) is connected to an end cap (22) provided at said other end of the cylinder (10) and having a lead- -through aperture for the elastic strand (19), said locking means (23) being arranged in the end cap. 5. Wound drainage according to any of claims 1 to 4, c h a r a c t e r i z e d in that the elastic strand (19) is provided with a grading for indicating the length of extension.

Inventors: SVENSSON J
Applicants: SVENSSON J
Application year: 1980
Main classification: A61M27
IPC codes: A61M1, A61M27