Apparatus for Aspirating Secreted Fluids From a Wound

FIG. 1 is a schematic illustration of the aspiration device;

FIG. 2 is a front view of the control device and the secretion aspiration pump;

FIG. 3 is a perspective view of the control device and the secretion aspiration pump;

FIG. 4 is a top view of the control device and the secretion aspiration pump;

FIG. 5 is a top view of the tube section to be placed into the secretion aspiration pump, together with the holder;

FIG. 6 is the circuit diagram of the aspiration device;

FIG. 7 is a schematic illustration of a first embodiment of a needle with a sleeve coupled thereto after the sleeve has been pressed through the tissue adjacent a wound;

FIG. 8 is a schematic illustration of the sleeve having been pressed through the tissue and of a drain at the beginning of its introduction into the sleeve;

FIG. 9 is a schematic illustration of the position of the drain after having passed through the sleeve and after withdrawal of the sleeve from the tissue;

FIG. 10 is an enlarged, partially illustrated longitudinal section through the sleeve and the needle according to the first embodiment;

FIG. 11 is a section according to the line XI--XI of FIG. 10;

FIG. 12 is a partially illustrated longitudinal section of a needle according to a second embodiment in connection with a sleeve;

FIG. 13 is a schematic illustration of a drain having passed through tissue by means of a needle according to FIG. 12; and

FIG. 14 is a schematic illustration of the drain placed according to FIG. 13 after separation of the needle and the subsequently completed connection with a tube.

An aspiration device for aspirating secreted fluid out of a wound consists as shown in FIG. 1, of a drain 1 to, be placed in the wound, a tube 3 running from the drain or catheter to a receptacle 2, a tube pump 4, a control device 5 which controls the pump, and a sensor device 6. The control device 5 and the sensor device 6 in the exemplary embodiment are located in a housing 7, on which the tube pump 4 is arranged. The receptacle 2 is preferably a plastic bag. The tube 3 in the exemplary embodiment is also made of plastic, with the exception of the section 3' to be attached in the tube pump 4, which is a silicon rubber tube. Because the tube 3 is nondetachably connected with the receptacle 2 and the drain 1, the drain 1, the tube 3 and the receptacle 2 form a closed system, the elements of which that come into contact with the wound and the wound's secreted fluid can be kept sterile and which does not have to be separated for use or during use.

The tube pump 4 includes a pump head 8 arranged on a rotatably mounted drive axis. This pump head 8 comprises, in the exemplary embodiment, a support 9 which is rigidly connected with the drive axis and in the exemplary embodiment is star-shaped, as well as respective rollers 10 arranged on each of the four arms of the support 9. These rollers 10 project over the arm ends and are rotatably mounted on and symmetric to axes lying parallel to the drive axis.

Referring now to FIG. 3, in order to bring the section 3' of the tube 3, on which the rollers 10 must act to achieve the pumping effect, comfortably into the correct position with respect to the pump head 8 and to also hold it in this position, a plastic, channel-like holder 11 is provided, which is provided at both ends with an elastic clamping element 12 that grasps the tube. The holder 11 is either formed as a reusable part of the tube pump or as a part of the throw-away system that always remains connected with the section 3'.

From the extended position illustrated with broken lines in FIG. 5, the holder 11 together with the section 3' of the tube 3 is bent into the U-shaped illustrated with solid lines in FIG. 5 and then placed into a holder 13 (FIG. 4) of a pump housing 14, which supports the pump head 8, whereby the holder 13 supports the U-shaped, bent holder 11 on its dies opposite the tube section 3'. Detent elements (not shown) secure the holder 11 against any shifting in its longitudinal direction.

The pump head 8 is driven via a transmission by an electric motor 15, which is formed in a known manner and is therefore shown only schematically (FIG. 6), the rotational speed of which is variable.

The adjustment of the rotational speed of the electric motor 15 takes place by means of the control device 5, which forms an interval control which is connected to two capacitive secretion sensors 16 and 17. The control device 5 has two oscillators 18, 18', behind which are connected voltage rectifiers 19, 19', which rectify the output voltage of the oscillators. The output of these two voltage rectifiers is connected to the input of respective amplifiers 20, 20'. These two amplifiers as well as the two voltage rectifiers and the two oscillators are identical. The output of the amplifier 20 is connected to one input and the output of the other amplifier 20' is connected to the other input of a logic circuit 21, in which an OR switch follows. The output voltage of the logic circuit 21 is led to the input of a power amplifier 22, which lies in the energy supply line of the electric motor 15 of the tube pump 4.

The first capacitive secretion sensor 16 lies in the oscillating circuit of one oscillator 18 and the second capacitive secretion sensor 17 lies in that of the oscillator 18'. Both secretion sensors have two electrodes 23 and 24 (FIG. 1), between which lie two spaced tube sections running in the longitudinal direction of the tube. This distance of the two electrode pairs from each other is greater than the usual length of air bubbles carried along in the secreted fluid.

Because the two electrode pairs 23 and 24 are arranged inside the housing 7, a plastic measurement chamber insert 25 is provided, which, as shown in FIG. 3, has a U-shaped outer form as well as a thickness that is adapted to the diameter of the tube 3. The side surfaces of the measurement chamber insert 25 bordering the outer shape form a channel to receive a section of the tube 3 lying between the drain 1 and the section 3'. Respective shaped clamping elements 26 hold the tube 3 in contact against the measurement chamber insert 25, which can be led through an opening in the rear wall of the housing 7 into the measurement chamber provided in the inside of the housing 7. In the measurement chamber the two electrode pairs 23 and 24 are arranged in such a manner that one or the other of the shanks of the tube 3 that are bent into a U-shape by the abutment against the insert 25, lie between them. Since the measurement chamber insert 25 is an inexpensive plastic element, at the end of the aspiration it can be pulled out of the housing 7 and thrown away together with the tube 3. Of course, it would also be possible to release the tube 3 from the insert 25 and reuse it.

As long as there is no secretion fluid or only a very small quantity of secretion so that between the electrodes 23 and 24 there are only the tube 3 and air and possibly only a small amount of secretion, the two secretion sensors 16 and 17 hold the oscillators 18, 18' in a condition in which their output voltage has a low level. The two output voltages, which are joined with each other in the logic circuit 12, because of their low levels, provide the result that the power amplifier 13 yields such a small voltage that the electric motor 15 connected thereto operates at a selectable rotational speed which corresponds to a desired minimum suction force. A foil keyboard 27 (FIG. 2) is provided on the front plate of the housing 7 to adjust various minimum rotational speeds. However, something such as a dial could also be used in place of such a keyboard. As long as the electric motor 15 operates at its low rotational speed, a control light 28 provided above the foil keyboard 27 is illuminated. In addition, the key of the foil keyboard 27 that was activated to adjust the rotational speed is illuminated.

As soon as one of the two secretion sensors 16 or 17 recognizes a larger amount of secreted fluid, because the secretion rate has increased, the output voltage of one of the two oscillators 18 or 18' reaches a high enough level that the output voltage of the logic circuit 21 effects an output voltage of the power amplifier 22 which leads to an increased rotational speed of the electric motor 15 and thereby to increased force in the tube pump 14. The increased rotational speed of the electric motor 15 can be selected by means of a second foil keyboard 29, which is also provided on the front of the housing 7. And of course this keyboard could also be replaced by other adjusting means, such as a dial. A second control light 30 in the front plate lights up while the electric motor 15 operates with the increased rotational speed. The increased power of the tube pump 4 is selected such that it is sufficient to be able to deliver the maximum rate of occurring secretion into the receptacle 2.

Air bubbles carried with the secretion fluid do indeed result in the first secretion sensor 16 initially, and somewhat later the second secretion sensor 17 effecting a lower level of output voltage of the associated oscillator 18, 18'. But since by the time the second secretion sensor recognizes an air bubble the bubble has already left the effective area of the first secretion sensor, and therefore the level of the output voltage of the oscillator controlled by the first secretion sensor is already back to the higher level, the electric motor 15 continues to operate with the higher rotational speed. A switching of the tube pump to the minimum power is not released by the two secretion sensors 16 and 17 until both detect only air or a reduced quantity of secretion. The tube pump 4 remains in this operating condition until, once again, at least one of the sensors 16 and 17 recognizes a secretion quantity that requires a switching to the higher power level.

Normally, the energy for the operation of the electric motor 15 and for the operation of the control device 5 is drawn from the public power supply via a power supply connection line 31 (FIG. 2). In order to prevent the electric motor 15 from stopping during a failure in the power supply, the housing 7 also contains an emergency battery which takes over the energy supply in case of a loss of power. When the emergency battery is in use, a third control light 32 provided in the front plate of the housing 7 is illuminated. In addition, another power switch is provided in the front plate.

In order to prevent causative organisms found on the skin surface 34 (FIG. 7) from entering the the wound during placement of the drain or catheter 1, a sterile, plastic sheath or sleeve 35, which constitutes a part of a guide for insertion of the drain or catheter 1, is used, the inside diameter of which is somewhat larger than the outside diameter of the drain 1. This sleeve 35 is pressed into the tissue 37 adjacent the wound from the inside with the aid of a metal needle 36, and is pressed through this tissue 37 until the sleeve 35 projects somewhat out of the skin surface 34.

As shown in FIG. 11, the sleeve 35 is provided with a longitudinal slot 38 which extends over its entire length. Diametrically opposite the longitudinal slot 38 is a recess 39 which also extends over the entire length and forms a film hinge. A thin foil tube 40 made of a plastic foil that is easy to cut is drawn over the sleeve 35 and holds the longitudinal slot 38 closed.

As shown in FIG. 10, a displaced pin 41 is coaxially threaded to the rear end of the needle 36. A plastic conical bushing 42 is pushed onto the smaller diameter portion of this pin adjacent to the end of the needle. The outside diameter of this conical bushing 42 at the end bordering on the needle 36 is equal to the outside diameter of the cylindrical lance and uniformly increases toward the other end until it reaches a value somewhat larger than the outside diameter of the sleeve 35. At this end there is joined thereto, in one piece therewith, a collar 43, the wall thickness of which is selected to be small enough that the collar 43 can easily be deformed. As shown in FIG. 10, the collar 43 has a conical shape so that it forms an extension of the conical bushing 42 which overlaps a portion of the end of the sleeve 35 adjacent the conical bushing 42 as well as the associated end section of the foil tube 40. The larger diameter section of the pin 41 has an outside diameter adapted to the inside diameter of the sleeve 35, so that the sleeve 35 can be pushed over this section of the pin 41 until it abuts the end of the conical bushing 42. Two diametrically opposite radial projections 44 on the portion of the pin 41 containing the sleeve 35, together with respective bent-angle slots 45 on the end section adjacent the conical bushing 42 form a bayonet closure by means of which the sleeve 35 can be form-fittingly connected with the needle 36 via the pins 41 and can be easily separated from the needle by a simple rotation. After the sleeve 35, with the aid of the needle 36, has been pushed from the inside through the tissue 37 to the point that the full length of the collar 43 is exposed, the needle 36 is rotated relative to the sleeve 35 in the direction of release for a bayonet closure and it is then removed from the end of the sleeve together with the pin 41, the conical bushing 42, and the collar 43. Thanks to the collar 43, the end of the sleeve 35 projecting out of the skin surface 34 has not come into contact with the surface of the skin 34 over a sufficiently large length so that when the drain 1 is then introduced into the outwardly extending end of the sleeve 35, the drain safely does not come into contact with the portions of the sleeve 35 that are contaminated, i.e., have come into contact with the surface of the skin 34.

After the drain 1 has been placed in the wound, the sleeve 35 is drawn out of the tissue 37 over the drain or the tube 3, as shown in FIG. 9. One need then only cut through the foil tube 40 in the longitudinal direction with the scalpel in order to be able to open the sleeve 35 and remove it from the tube 3. After closure of the wound the tube pump is first placed into operation at the low suction rate. It then automatically increases the suction force when necessary due to the secretion sensors 16 and 17.

A modified embodiment of a needle is illustrate FIG. 12 which is distinguished from the above-described needle illustrated particularly in FIG. 10 only in that in the area of its end section opposite the conical bushing, the collar 43' of the conical bushing 42' placed on the rear needle end lies closely against the outer surface of the foil tube 40 and is glued thereto. This reliably excludes the possibility of causative organisms being able to enter the section of the sleeve 35 and of the foil tube 40 overlapped by the collar 43'. Because of further details concerning the embodiment of the needle 36', the conical bushing 42', and the connection of the needle 36' with the sleeve 35, reference will be made to FIG. 10 and the associated text to the extent that there are no differences.

As shown in FIGS. 13 and 14, the needle 36' with its conical bushing 42' and the collar 43' formed in one piece therewith can also be used to advantage in the placement of a drain even when the sleeve 35 has not previously been pressed through the tissue 37 adjacent the wound.

This is also true, of course, for the needle 36 with its conical sleeve 42 and the collar 43.

Both the collar 43 and the collar 43' namely enclose the end section of the drain 101 to be connected with the needle 36 and thereby prevent this end section from coming into contact with causative organisms on the surface of the skin 34 as the skin is penetrated. If a needle 36' with a collar 43' is used, the free end section of which is secured to the end of the drain, then the end section 43" securely connected with the drain 101 is separated from the remaining portion of the collar 43' by a cut with a scalpel before the needle 36' is separated from the drain 101. The separation of the needle from the drain is easily performed with the use of a needle 36 with a collar 43. The end section of the drain 101 no longer covered by the collar 43 or 43' is free of germs. Therefore, no germs can enter the system from this area if the drain 101 is then coupled with a tube 103, as illustrated in FIG. 14.

Although only preferred embodiments are specifically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.