Connector for a medical device

Abstract

The present invention provides a wound dressing tubing connector, comprising a first unit and a second unit which are releasably connectable and which when connected form a fluid path through the connector, wherein the first unit comprises an inlet and an outlet and wherein the second unit comprises an inlet and an outlet, in which the outlet of the first unit and the inlet of the second unit when connected together define the fluid path, and wherein the first unit and the second unit are connectable to form an air and fluid tight seal and wherein the first unit and/or the second unit comprises a pressure regulator valve in fluid communication with the fluid path. Also provided are systems, kits and methods of treatment.

Claims

1. A wound dressing tubing connector comprising a first unit and a second unit which are releasably connectable and which when connected form a fluid path through the connector wherein the first unit comprises an inlet and an outlet and the second unit comprises an inlet and an outlet, in which the outlet of the first unit and the inlet of the second unit when the first and second unit are connected together define the fluid path, and wherein the first unit and the second unit are connectable to form an air and fluid tight seal; and wherein the first unit and/or the second unit comprises: a connector body having a fluid-flow bore of fixed lateral extent extending between the said inlet and the said outlet, the fluid-flow bore forming at least part of the said fluid path; the said connector body having a tube-receiver portion at one end thereof to receive an end of a wound-dressing tube; the said connector body having a pressure regulator valve which is spaced from the tube-receiver portion along the fluid flow bore; the pressure regulator valve having a valve body which extends from a side of the fluid flow bore; the said valve body having a valve bore which intersects with the said fluid-flow bore, such that the pressure regulator valve is in fluid communication with the said fluid path; the pressure regulator valve having a valve seal and a spring which are in the said valve body to close the said valve bore; the spring is configured to act against the valve seal to close the pressure regulator valve when the pressure in the fluid path reaches a differential pressure relative to atmospheric pressure that is greater than or equal to the positive force of the spring, the pressure regulator valve being configured such that when the pressure in the fluid path is sufficiently low, whereby a differential pressure created relative to atmospheric pressure is equivalent to the positive force of the spring, the spring force is overcome to release the valve seal so that atmospheric air enters the valve bore and flows over the said spring along the valve bore to the said fluid flow bore in order to equalise the pressure in the fluid path.

2. The connector according to claim 1, wherein the pressure regulator valve is arranged adjacent the fluid path.

3. The connector according to claim 1, wherein an outlet of the fluid conduit is provided with a non-uniform boundary comprising an uneven surface, castellations, slots and/or openings.

4. The connector according to claim 3, wherein the non-uniform boundary is provided on a valve seat element.

5. The connector according to claim 1, wherein the pressure regulator valve is arranged substantially perpendicularly to the fluid path.

6. The connector according to claim 1, wherein the first unit and/or the second unit comprises more than one pressure regulator valve.

7. The connector according to claim 1, wherein the valve is provided in the fluid conduit.

8. The connector according to claim 1, wherein the connector is releasably connectable using a bayonet twist sealing system.

9. The connector according to claim 8, wherein the connector is releasably connectable by means of a male and female sealing system and wherein the outlet of the first unit is configured to provide a male spigot and the inlet of second unit is configured to provide a female spigot.

10. The connector according to claim 1, wherein the air and fluid tight seal is provided by means of one or more of a spring, a gasket or an O-ring, interposed between the first unit and the second unit.

11. The connector according to claim 1, further comprising a first tube connected to the inlet of the first unit.

12. The connector according to claim 1, further comprising a second tube connected to the outlet of the second unit.

13. A system for applying sub-atmospheric pressure to a wound dressing comprising a connector of claim 1, a vacuum source and a wound dressing, wherein the vacuum source is in fluid communication with the wound dressing via the connector.

14. A wound dressing tubing connection kit comprising: (a) the wound fluid connector of claim 1, (b) a first tube, wherein the first tube is connectable to an outlet of a wound dressing and the inlet of the first unit, (c) a second tube, wherein the second tube is connectable to the outlet of the second unit and optionally, (d) the wound dressing.

15. The kit of claim 14, further comprising a vacuum source having an inlet, the second tube being connectable to the inlet of the vacuum source.

16. The kit of claim 15, wherein the vacuum source is a peristaltic pump, a hospital wall suction device, a portable suction device, a bellows suction device or a suction device powered by a spring means.

17. The connector according to claim 1, wherein the pressure regulator valve comprises only one said spring.

18. The kit of claim 14, wherein the wound dressing comprises a pad for placing in the wound composed of reticulated open cell foam, gauze, and/or an absorbent dressing material.

19. A wound dressing tubing connector comprising a first unit and a second unit which are releasably connectable and which when connected form a fluid path through the connector wherein the first unit comprises an inlet and an outlet and the second unit comprises an inlet and an outlet, in which the outlet of the first unit and the inlet of the second unit when the first and second unit are connected together define the fluid path, and wherein the first unit and the second unit are connectable to form an air and fluid tight seal; and wherein the first unit and/or the second unit comprises a pressure regulator valve in fluid communication with the fluid path; the pressure regulator valve having a valve seat element, a valve seal and a spring, the valve seal and spring being located between the valve seat element and an inlet to the fluid path; wherein the spring is configured to act against the valve seal to close the pressure regulator valve when the pressure in the fluid path reaches a differential pressure relative to atmospheric pressure that is greater than or equal to the positive force of the spring, the pressure regulator valve being configured such that when the pressure in the fluid path is sufficiently low, whereby a differential pressure created relative to atmospheric pressure is equivalent to the positive force of the spring, the spring force is overcome and atmospheric air enters the connector to equalise the pressure in the fluid path.

Description

(1) The invention will now be described by way of example with reference to the following drawings in which:

(2) FIG. 1 shows a cross-sectional view of a connector as separate male and female units before connection.

(3) FIG. 2 shows a cross-sectional view of a connector after separate male and female units are connected with operation under normal conditions.

(4) FIG. 3 shows a cross-sectional view of a connector with separate male and female units connected with operation under conditions where internal negative pressure has reached a level equivalent or greater than the compressive force exerted by the spring means.

(5) FIGS. 4, 5 and 6 show embodiments of the invention in which two valves are present.

(6) FIG. 7 is an isometric view of a wound dressing tubing connector (1) of the invention.

(7) FIGS. 8 and 9 show specific embodiments of the invention.

(8) FIG. 10 is an isometric view of a wound dressing tubing connector (1) of the invention in which the pressure regulator valve is connected indirectly to the fluid path.

(9) As shown in FIG. 1, wound dressing tubing connector (1) consists of first unit or dressing side (connector) half (5) configured as a male spigot to which tube (3) is fitted. The second unit or pump side (connector) (7) is configured as a female spigot and consists of tube (11) fitted to the connector in which region (9) is connectable to the first unit.

(10) First and second connector units (5) and (7) can be mated via a latching mechanism to form a continuous internal path (25) and an air tight seal. Tube (3) typically will be connected to a wound dressing and tube (11) to a pumping mechanism or vacuum source (12).

(11) O-ring (13) provides and air tight seal between connector halves (5) and (7), additionally providing an opposing force when it is compressed by connector region (9) that exerts a constant frictional force between the two connector halves which reduces the risk of accidental disconnection.

(12) Wound dressing tubing connector (1) has an integrated valve body (15). Valve body (15) accommodates a compression spring (17) which acts between spring locator (19) and valve seal (21). This arrangement allows seal (21) to press against the valve seat (23) thus sealing the inside of the connector assembly and tubing from atmospheric pressure.

(13) In normal conditions as shown in FIG. 2, fluid or air passes through internal path (25) at the pressure determined by the pump or vacuum source (12). As shown in FIG. 3, once the internal negative pressure reaches a level that is equivalent or greater than the compressive force exerted by spring (17), the atmospheric air will overcome the spring force and air will enter the connector by bypassing seal (21) creating a fluid conduit (27). This will have the effect of lowering the internal negative pressure until equilibrium is restored by the spring force exerted by the spring (17).

(14) In normal operation a seal is obtained between the negative pressure source (12) which is connected either directly or indirectly to (7) and this in turn is connected to a sealed wound dressing. Fluid is drawn up the fluid path (25) away from the wound site towards the negative pressure source (12). In order to regulate the pressure at a pre-determined level, a valve (15) is connected to one or both halves of the connector. This valve (15) provides a means of air at atmospheric pressure entering the fluid conduit (27) and reducing the negative pressure in the connector and subsequently at the wound site.

(15) Various configurations of connectors are possible including those that have a twist bayonet action in order to lock the mating halves (5) and (7) together. Other configurations include a buckle style system and twist lock system such as used in a Luer lock device. A seal is used in the form of an O-ring or a gasket between the two halves to ensure atmospheric air does not enter the connector in an uncontrolled manner and also to prevent fluid leaks from the fluid path (25).

(16) Due to the arrangement of the valve(s) body (15), fluid is free to flow unimpeded through pathway (25) irrespective of the action of the valve. A non-uniform boundary, for example, an uneven surface, castellations, slots or openings can be provided on valve body (15) to prevent the air entry into the connector from becoming blocked.

(17) FIGS. 4, 5 and 6 show the invention with two valves as an alternative embodiment. The advantage of two valves over one is that it reduces the risk of the system failing due to a valve blockage.

(18) The connector halves (the male unit and the female unit) are mated using a latching mechanism to provide a continuous internal path for fluid or air and to seal the internal path from atmospheric air.

(19) The latching mechanism consists of a barbed arrangement that locks in place when the two halves are rotated in an opposing direction. The O-ring provides a compression force that prevents the two halves accidentally becoming undone.

(20) Other latching mechanisms may be employed including Luer-lock type connector systems, screw threads, buckle style snap fits or ball detent systems.

(21) FIG. 7 is a diagrammatic representation in isometric view of a wound dressing tubing connector (1) of the invention.

(22) FIG. 8 shows a first unit (5) of the invention configured as a male spigot. The first unit (5) of FIG. 8 may be connected as shown in FIG. 9 to a second unit (7) configured as a female spigot using a twist bayonet action.

(23) FIG. 9 shows connector (1) which consists of two mating halves (5) and (7) which are connected to form an air and fluid tight seal.

(24) In order to control the pressure in a controlled manner a pressure regulating valve (15) is required as shown in FIG. 1. One configuration of this valve is shown in FIGS. 8 and 9, in which the valve body (15) is fitted into a cavity within the connector body (5), compression spring (17) is fitted between the connector body and valve seal (21). When the pressure inside the fluid path (25) is equivalent to pressure outside the conduit path then the valve seal (21) is closed due to the positive pressure of the spring (17), this prevents air at atmospheric pressure entering the connector or fluid leaking out of the connector. When the pressure in fluid path (25) reaches a differential pressure to atmospheric pressure that is equivalent to the positive force of the spring, the spring force will be overcome and atmospheric air will enter the connector to equalise the pressure. By this configuration the selection of spring rate can control the negative pressure within the connector to provide accurate therapeutic pressure at the wound site and aid the removal of fluid whilst ensuring it does not leak out of the connector. In this example an O-ring (13) provides the means of ensuring a seal between the fluid conduit path on both halves of the connector.

(25) In the example illustrated in FIGS. 8 and 9 two valves are incorporated into a single connector body to provide an additional safety feature if one valve should malfunction or become blocked.

(26) Alternative configurations include arranging the valves in a Y configuration.

(27) Alternative sealing systems to the male and female sealing system may be employed including a face sealing system, an external locking collar and/or a magnetic latching system. The alternative sealing systems may be implemented by use of connector halves that do not have a male and female spigot but are coupled by alternative means such as face sealing utilising a barb latch, external rotating collar or magnetic sealing. Any of the above sealing systems may be used in conjunction with a male and female sealing system and/or the latching systems described above or as alternatives thereto.

(28) FIG. 10 is a diagrammatic representation in isometric view of a connector (1) where the pressure regulator valve (15) is connected to the fluid path (28) via a separate conduit, an air pathway (29) that runs in parallel to the fluid path (28) and may interconnect to the fluid path (28) remotely from the connector or separately, for example at the wound site. The fluid inlet tube (28) extends between the wound dressing and the first unit (5) of the connector. The air pathway (29) may extend between the pressure regulator valve and the wound dressing (not shown). The distal end of the fluid inlet tube (28) may terminate at the wound dressing and allows air from the air pathway (29) to enter the wound site. The outlet (8) extends between the second unit (7) of the connector and the pump. When the first unit (5) is attached to the second unit (7) a fluid path through the connector is formed.

(29) The following example is provided also for the purposes of illustration only and is not to be construed as being limiting on the invention.

(30) Experiment 1: Testing the Connector

(31) With a closed system (air only) utilising a peristaltic pump it was demonstrated that the pressure could not be controlled adequately, as the pump speed increased the pressure correspondingly increased to in excess of 350 mmHg. Decreasing the pump speed did not effectively reduce the pressure and it remained at over 200 mmHg even at the lowest setting used of 5 RPM. Any pressure decrease was only due to connector leakages and the breathability of the drape.

(32) With the proposed pressure valve fitted at the dressing site at full speed of 200 mmHg the wound site pressure was limited to 125 mmHg+/−25 mmHg with a momentary maximum of 150 mmHg as the valve initially opened.

(33) With fluid introduced at 30 rpm a constant flow rate was achieved. The fluid flow was aided by small amounts of air being drawn through the valve which allowed mobility of the fluid from the dressing to the container.

(34) Changing the height of the dressing relative to the pump (0.5 metres) did not result in any measurable pressure change at the wound-site.

(35) Results

(36) A standard pressure control valve was used in the reverse orientation i.e. the normal outlet to atmosphere was connected to the fluid side, the variance of negative pressure readings was well within the stated manufacturers tolerance of +/−20%, which would normally relate to a total tolerance of 25 mmHg at the normal working pressure. The pressures measured after the valve originally opened and the pressure stabilised to be in the order of 10 mmHg total working tolerance.

(37) This is believed to be significantly more accurate than electronic control systems that rely on multiple conduit pathways and multiple electronic components.

(38) The introduction of the pressure valve had a second effect beyond pressure control that was not anticipated, this was to allow the introduction of small amounts of air into the system at the dressing site. This had two effects, the first was to allow constant flow of fluid from the dressing at a very low flow rates, the second was to provide a mechanism to reduce pressure at the wound site when sealed pump systems such as a peristaltic pump is used. Additionally the valve had the effect of aerating the fluid evenly causing mobility which appeared to be different in nature when a basic leak is introduced through an orifice. One explanation for this may be due to the design of the valve and the characteristics of the sprung loaded component and seat, although this valve is designed to relieve positive air pressure it has an advantageous effect in regulating air inflow under negative pressure when fitted in reverse. A second major advantage of the valve arrangement is due to the reverse nature of the sprung loaded action when fluid is forced back into the dressing the valve will be forced closed effectively sealing the dressing. Several scenarios exist when this can happen; one example is when therapy is paused for when the patient is taken a shower, in this case gravity or pressure against the dressing could cause fluid to pool in the dressing, and normally if the dressing contained any passage to atmosphere then fluid could leak out causing an infection risk.

(39) In the case of devices that contain sensing tubes or conduits to the control unit to control pressure these can potentially fill with fluid when negative pressure is paused that may cause blockages, this situation is eliminated in the present invention.