Suction systems

Abstract: A medico-surgical suction system has a container 1 with an outlet 10 connected to a vacuum pump 2, and an inlet 11 connected to a suction catheter 3 via a dual-lumen tube assembly 4 one end of which is connected to the container 1 and the other end of which has a suction control 43 and a coupling 45 for the catheter. A valve 100 located in the outlet 10 of the container 1 is connected to the suction control 43 via a minor lumen 41 of the tube 4. A side lumen 106 enables the vacuum pump 2 to apply reduced pressure to one end of the valve 100, which holds the valve off against the action of a spring 107. Actuating the suction control 43 allows air to flow to the valve 100 via the minor lumen 41 so that the effect of the reduced pressure is overcome and the spring 107 opens the valve 100, thereby applying suction to the catheter 3.

Description: This invention relates to medico-surgical suction systems of the kind including a suction container having an inlet and outlet, a vacuum source connected to the container outlet, a suction tube assembly having a first end connected with the container inlet and a second end having a first coupling, a suction catheter assembly having a first end with a second coupling that is removably engageable with the first coupling on the second end of the suction tube assembly, and a manually-operable suction control device that controls suction applied by the catheter assembly The invention is more particularly concerned with systems used for aspirating secretions from a patient's trachea or an artificial airway such as a tracheostomy or other tracheal tubes. The invention can also be used for removing blood and debris from surgical sites. Suction systems of this kind generally comprise a container and a suction catheter connected to the container inlet, the outlet of the container being connected to a vacuum pump so that a reduced pressure is created in the container, which, in turn, applies suction to the catheter. In such systems, the vacuum pump generally operates continuously and the catheter includes a valve by which suction at the tip of the catheter can be controlled. In its simplest form, the valve comprises an aperture in the wall of the catheter, which, when open, allows air to enter the catheter and thereby prevents any significant suction effect at the tip. The aperture can be closed, when desired, by the thumb of the user, or by a movable flap, so that the suction effect is confined to the tip of the catheter. The valve is located close to the patient end of the catheter so that the surgeon can control the valve with the same hand as he uses to manipulate the tip of the catheter. Examples of such catheters are described in US 3,911,919 and US 4,468,216. The problem with this form of valve is that the suction control aperture provides a path through which contaminated material sucked into the catheter can leak out. This is a significant disadvantage in view of the present concern about cross-infection and the transmission of infectious diseases. In order to reduce the risk of escape of material, catheters have been made including a sealed valve. Examples of suction catheters with a push-down spool valve are shown in US 4,680,026, US 4,526,573 and US 4,502,508. A suction catheter with a resilient valve member is described in US 4,569,344. Many other forms of suction catheter with different suction control valves are also known, such as described in US-A-4062360 where a vacuum is applied externally of a resilient, normally-closed tube to cause it to open and permit flow through it. One problem with these valves is that, because they must have a high integrity seal to prevent escape of suction fluid externally of the device and inadvertent suctioning of the patient, the cost of the valve forms a large part of the total cost of the system. This is a particular disadvantage in a product that is disposed of after use on one patient. Another problem is that there can be a risk of blockage in the valve, especially where the catheter is used for suctioning of fluid containing thick tenacious mucous, tissue debris or blood clots. Currently-available valves form an integral part of the suction system and are specified for 24 hour use on a single patient. The valves cannot be re-used because this would involve re-use of the system as a whole and the attendant risk of cross-infection. It is an object of the present invention to provide an improved suction system. According to the present invention there is provided a medico-surgical suction system of the above-specified kind, characterised in that the suction catheter assembly is provided without any valve and that the suction control device is provided on the second end of the suction tube assembly, the suction tube assembly extending through the suction control device to the first coupling, such that the suction control device may be used with a plurality of suction catheter assemblies. The suction catheter assembly may include an aspiration catheter that extends from the second coupling, a flexible envelope that extends from the second coupling around the outside of the aspiration catheter to a third coupling that mates with a tracheal tube, and the aspiration catheter being capable of being advanced through the third coupling into the tracheal tube.The suction control device may include a valve. Alternatively, the system may include a valve located adjacent the container and a connection between the suction control and the valve such that the valve can be controlled remotely. The valve may be located at the outlet of the suction container and be operable to control suction applied at the container inlet. The valve preferably includes a valve member that is displaceable between an open state in which suction is applied at the container inlet and a closed state in which no substantial suction is applied at the container inlet, the valve including a spring urging the valve member to one of the open and closed states, a side lumen connecting the vacuum source with the valve member, which is operable to apply a reduced pressure to the valve member and urge it to the other of the open and closed states, and the suction control device controlling the application of reduced pressure to the valve member and thereby controlling operation of the valve. The system may include a suction control lumen extending between the suction control device and the side lumen, the suction control including an orifice that can be opened and closed by the user to control entry of air into the suction control lumen and thereby control the application of reduced pressure to the valve member. The spring may urge the valve member to an open state, the side lumen being connected to apply suction to urge the valve member to a closed state, and the suction control device having a normally-closed orifice that can be opened to allow air into the side lumen so as to reduce the effect of the reduced pressure on the valve member and allow the valve member to be displaced to an open state. Alternatively, the spring may urge the valve member to a closed state, the side lumen being connected to apply reduced pressure to urge the valve member to an open state, and the suction control device having a normally-open orifice which can be closed to prevent air entering the side lumen so as to enable a reduced pressure to be applied on the valve member and thereby allow the valve member to be displaced by the reduced pressure to an open state. The valve means preferably includes a recess along which the valve member is displaceable, the side lumen opening into one end of the recess such that reduced pressure applied by the vacuum source via the side lumen urges the valve member to the one end of the recess, and a control lumen extending from the suction control device and opening into the one end of the valve recess. A suction system including a suction catheter assembly, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:. Figure 1 shows one form of the system; Figure 2 is a sectional side elevation view of a part of the container shown in Figure 1 to an enlarged scale; Figure 3 is a sectional side elevation view of the suction control shown in Figure 1 to an enlarged scale; Figure 4 is a sectional side elevation view of an alternative suction control; Figure 5 is a sectional side elevation view of a part of an alternative container used with the suction control of Figure 4; Figure 6 is a side elevation view of a part of a further alternative system; and Figure 7 is a side elevation view of a part of another alternative system. With reference first to Figures 1 to 3, the suction system comprises a container 1, a vacuum pump 2 connected to the outlet 10 of the container, a suction catheter assembly 3 and a suction tube assembly 4 connected between the suction catheter assembly and the inlet 11 of the container. The container 1 has a cylindrical moulded plastics vessel 12 closed at its lower end by an integral base. The upper end of the vessel 12 is closed by a separate cap assembly 13 sealed to the vessel. The cap 13 assembly is moulded from plastics and includes integrally within it, the inlet 11 and outlet 10 of the container. The inlet 11 comprises a vertical spigot 14, at its lower end, projects downwardly close to the base of the container 1. A main inlet bore 15 extends through the spigot 14 which, at its lower end opens into the container 1, and at its upper end, communicates with a major lumen 40 through the suction tube assembly 4. The suction tube assembly 4 is permanently sealed into an annular recess 16 at the upper end of the spigot 14. In an alternative arrangement, the suction tube assembly 4 could be connected to the spigot 14 by removable couplings. Extending parallel to the inlet bore 15, within the wall of the spigot 14, is a valve control lumen 17 communicating with a minor lumen 41 extending along the suction tube assembly 4. The valve control lumen 17 extends down the upper part of the spigot 14 and along a conduit 18 extending between the inlet 11 and outlet 10. At its left-hand end, the lumen 17 opens into a valve 100. The valve 100 is located within the outlet 10 of the container 1. The outlet 10 takes the form of a vertical spigot 101 projecting a short distance down into the vessel 12. At its upper end, the spigot 101 is shaped into a coupling 102 to which can be mated a cooperating coupling 20 on the end of tubing 21 extending to the vacuum pump 2. An outlet bore 103 extends along the spigot 101 and opens into the vacuum tubing 21. Extending transversely across the bore 103 within the spigot 101, is a valve recess 104 in which is located a slidable valve member 105. At its right-hand end, the valve recess 104 communicates with the control lumen 17 and with a side lumen 106 extending to that part of the bore 103 above the valve 100. The right-hand end of the valve recess 104 also contains a helical spring 107, which urges the valve member 105 to the left. In the position shown, the valve member 105 is in its right-hand, closed position, blocking the bore 103. When displaced to the left, an aperture 108 in the valve member 105 aligns with the bore 103 so that the valve 100 is open. The suction tube assembly 4 comprises a flexible tube 42 extruded with two lumens namely the major, suction lumen 40 and the minor, control lumen 41, which is of smaller cross-section. The dual-lumen tube 42 may be several metres long and extends to a suction control 43 at the patient end of the assembly 4. The suction control 43 has a plastics casing 44 within which the tube 42 is split into its two component lumens 40 and 41. That part of the tube providing the major, suction lumen 40 extends to a female coupling 45 formed at the right-hand, patient end of the casing 44. The remaining part of the tube 42, providing the control lumen 41, extends to a conduit 46 formed in the casing 44 and which opens on its surface via an orifice 47. A whistle 48 may be mounted in the orifice 47 to provide audible feedback when suctioning is in progress. In the position shown, air flow along the conduit 46 is prevented by a valve member 49, which projects into the conduit. The valve member 49 is formed at one end of U-shape resilient plastic component 50. The lower arm 51 of the component 50 rests on the inside of the casing 44 whereas the upper arm 52 is provided with ribs 53 and is exposed through an opening 54 in the casing. The resilience of the component 50 urges its two arms 51 and 52 apart, the separation of the arms being limited by engagement of the lower arm 51 with the casing 44 and by engagement of a lip 55 on the upper arm with the underside of a ledge 56 on the casing. The upper arm 52 can be pushed down, through the opening 54, to displace the valve member 49 so that an aperture 59 in the valve member aligns with the conduit 46 and the suction control 43 is thereby turned on. The suction catheter assembly 3 includes a male machine end coupling 30 adapted to mate with the female coupling 45 on the suction control 43. A flexible aspirating tube or catheter 31 extends from the coupling 30 within an outer protective, flexible envelope 32. At the patient end of the assembly 3 there is a patient connecting member or T-coupling 33 to which the envelope 32 is joined. The T-coupling 33 has a first port 34 through which the aspirating tube 31 extends and which is shaped to mate with a coupling 6 at the end of a tracheal tube 7. The side ports 35 and 36 enable the coupling 33 to be connected in a ventilating circuit so that ventilation can take place in the usual way whilst suctioning is in progress. A sliding seal 37 in the coupling prevents gas flow into the envelope. The suction catheter assembly 3 does not require any valve. The suction catheter assembly 3 and the suction tube assembly 4 together provide a suction inlet assembly 5 of the system. In order to effect suctioning, the pump 2 is switched on and the port 34 on the T-coupling 33 is connected to the coupling 6 on the tracheal tube 7. In its natural state, the suction control 43 is off, preventing passage of air into the control lumen 41 of the tube 42 and hence into the control lumen 17 of the container cap assembly 13. Because no air can enter the control lumen 17, and hence the right-hand end of the valve recess 104, a reduced pressure is created in the recess by the pump 2, via the side lumen 106. This reduced pressure is sufficient to overcome the force of the spring 107 and hold the valve member 105 towards the right-hand end of the valve recess 104 so that the valve 100 is held off. The vacuum pump 2 is, therefore, isolated by the valve 100 from the container 1 so that no suction is created in the suction tube assembly 4 or at the tip of the aspirating tube 31. When suction is required, the user grips the suction control 43 and squeezes down the upper arm 52 of the resilient component 50, so that the valve member 49 is displaced down to its open position in which the aperture 59 aligns with the conduit 46. This allows air to be drawn through the orifice 47 into the conduit 46 and into the control lumen 41 of the tube 42. Air flows from the control lumen 41 of the tube 42, via the control lumen 17 in the container cap assembly 13 and into the right-hand end of the valve recess 104. The effect of the reduced pressure in the right-hand end of the recess 104 is thereby reduced and the pressure rises close to atmospheric pressure, which is too high to overcome the force of the spring 107. The spring 107 is, therefore, now free to displace the valve member 105 to the left-hand end of the recess 104 so that the aperture 108 aligns with the bore 103, thereby opening the valve 100 and allowing the vacuum pump 2 to create a reduced pressure in the container 1. This applies suction, via the major bore 40 through the tube 42, to the aspirating tube 31. The aspirating tube 31 is advanced into the tracheal tube 7 by manipulating through the envelope 32 so that secretions and other material are sucked into the aspirating tube, along the major lumen 40 of the suction tube 42 and into the container 1. The whistle 48 sounds while suctioning takes place. When the suction control 43 is released, the resilience of the component 50 displaces the valve member 49 upwardly to a closed, off position. The control lumen 17 is now sealed from atmospheric pressure and the pump 2 will create a negative pressure in the right-hand side of the valve recess 104 via the side lumen 106. This causes the valve 100 in the container 1 to close, terminating suction. After suctioning of the tracheal tube, the aspirating tube 31 is pulled back into its envelope 32 and the assembly 3 is uncoupled from the suction control 43 for disposal. The suction tube assembly 4 can be coupled to a fresh catheter assembly 3 when it is next required for suctioning. The suction tube assembly 4 is reused until the container 1 is full. When this happens, the vacuum tubing 21 is uncoupled from the outlet coupling 102 on the container cap assembly 13. The coupling 45 on the suction control 43 is preferably arranged so that it can be coupled onto the outlet coupling 102, thereby sealing the contents in the container 1 so that it can be disposed of in the usual way. By locating the valve 100 remotely of its control 43, there is no risk that leakage from the valve will contaminate the user. It will be appreciated that various modifications are possible to the invention. The suction catheter need not be a tracheal tube aspirating catheter but could be a short rigid tube used for suctioning of, for example, a surgical site. By making the suction control reusable, the suction catheter assembly itself need not have any valve and can, therefore, be made at lower cost. The use of a female coupling on the suction control reduces the risk of contact with suction substances after uncoupling the catheter assembly. The suction control and the valve on the container could take various different forms. The valve need not be built into the top of the container but could be a separate component plugged in-line between the container outlet and the suction pump 2. Figure 6 shows an arrangement in which a filter 60 is connected between the inlet 10 of a conventional container 1, and a valve 61 is connected between the filter and the suction pump 2. A length of tubing 62 extends from a coupling 63 on the container inlet 11, which has a branch arm 64 that connects with the control lumen 41 extending along the tubing 4. The valve 61 may be the same as the valve 100 shown in Figure 2. The valve could be located on the inlet instead of the outlet, although there is less risk of the valve sticking when it is located on the outlet where it will not come in contact with liquid and suction debris. The consequences of leakage from the valve are also less if the valve is located on the outlet. In the arrangement of Figure 7, the valve 61' and the suction control 43' are independent of the tubing 4' so that the tubing can be disposed of periodically and the valve reused. The suction control 43' is clipped onto the tubing 4' close to the coupling 45' which connects with the suction catheter assembly 3. The suction control lumen 41' which connects the suction control 43' to the valve 61' is independent of the tubing 4' but is clipped to it during use by one or more releasable clips 80. The valve 61 is connected in the vacuum tubing 21' so that the container 1', tubing 4' and suction catheter assembly 3 can all be disposed of whilst retaining the valve, its control 43' and the connecting control lumen 41' for reuse. The suction control 43' could be clipped onto the suction catheter assembly 3, close to its patient end, so that the user can control suction at a point very close to where the aspirating tube is inserted. With reference to Figures 4 and 5, there is shown an alternative suction control 43' and valve 100' on the container 1'. In the suction control 43', the control lumen 41' of the suction tubing 42' is connected to a conduit 46' which opens through an orifice 47' without the interruption of any valve. The surface of the casing 44' around the orifice 47' is provided with a shallow concave recess 56' on which the user's finger or thumb is rested to cover the orifice. The valve 100' is similar to that shown in Figure 2 and differs only in the construction the valve member 105' and its mode of operation. In particular, the valve member 105' differs from the earlier described valve member 105 in that its through aperture 108' is located at the left-hand end of the valve member so that the bore 103' is closed when the valve member 105' is located at the left-hand end of the recess 104'. In its rest position, with the orifice 47' in the suction control 43' exposed, the right-hand end of the valve recess 104' is close to atmospheric pressure; the spring 107' is in its expanded state, forcing the valve member 105' to the left-hand end of the recess 104'. The bore 103' is, therefore, blocked and the vacuum pump is isolated from the container 1'. When the user places his finger or thumb on the recess 56' of the suction control 43', it covers the orifice 47' and prevents air entering the control lumen 41'. This allows the vacuum pump 2 to reduce the pressure at the right-hand end of the valve recess 104' which in turn causes the valve member 105' to be displaced to the right along the recess, compressing the spring 107'. In its right-hand position, the aperture 108' in the valve member 105' is aligned with the bore 103' so that the valve 100' is opened and the vacuum pump is connected to the interior of the container 1'. Various other forms of valve are possible, for example, it might be desirable in some circumstances to use a valve that is completely sealed against the escape of liquid. Such a valve could take the form of a continuous fluid passageway that is deformable to prevent flow through it. The suction control could itself include a valve that prevents flow into the suction tube assembly, which in this arrangement need only have a single bore. The valve could, for example, be a spool valve or a pinch valve that opens and closes the passage along the suction lumen at the suction control itself. The container may take various different forms. For example, the container might have a flexible liner 110' such as of the kind described in GB 2207709 or US 3,780,738 and as illustrated in Figure 5. In this arrangement, the inlet 11' of the cap assembly 13' communicates with the interior of the liner 110' whereas the outlet 10' communicates with the space in the container 1' outside the liner 110'. In such an arrangement, the cap assembly 13' with the liner 110' attached can be disposed of and the vessel reused. Where the container does not have a liner, the outlet may be provided with a safety valve to prevent over-filling, and a filter to prevent passage of airborne bacterial or aerosol droplets to the vacuum pump.

Claims: A medico-surgical suction system including a suction container (2) having an inlet (11) and outlet (10), a vacuum source (2) connected to the container outlet (10), a suction tube assembly (4) having a first end connected with the container inlet (11) and a second end having a first coupling (45), a suction catheter assembly (3) having a first end with a second coupling (30) that is removably engageable with the first coupling (45) on the second end of the suction tube assembly (4), and a manually-operable suction control device that controls suction applied by the catheter assembly, characterised in that the suction catheter assembly (3) is provided without any valve and that the suction control device (43, 43') is provided on the second end of the suction tube assembly (4), the suction tube assembly (4) extending through the suction control device (43, 43') to the first coupling (45), such that the suction control device (43, 43') may be used with a plurality of suction catheter assemblies (3). A suction system according to Claim 1, characterised in that the suction catheter assembly (3) includes an aspiration catheter (31) that extends from the second coupling (30), a flexible envelope (32) that extends from the second coupling (30) around the outside of the aspiration catheter to a third coupling (33) that mates with a tracheal tube (7, 6), and that the aspiration catheter (31) can be advanced through the third coupling (33) into the tracheal tube (7, 6). A suction system according to Claim 1 or 2, characterised in that the suction control device includes a valve. A suction system according to Claim 1 or 2, characterised in that the system includes a valve (100, 100') located adjacent the container (1) and a connection (41, 41') between the suction control device (43, 43') and the valve (100, 100') such that the valve can be controlled remotely. A suction system according to Claim 4, characterised in that the valve (100, 100') is connected at the outlet (10) of the suction container (1), and that the valve is operable to control suction applied by the container inlet (11). A suction system according to Claim 4 or 5, characterised in that the valve (100, 100') includes a valve member (105, 105') that is displaceable between an open state in which suction is applied at the container inlet (11) and a closed state in which no substantial suction is applied at the container inlet, that the valve (100, 100') includes a spring (107, 107') urging the valve member (105, 105') to one of the open and closed states, a side lumen (106) connecting the vacuum source (2) with the valve member, which is operable to apply a reduced pressure to the valve member (105, 105') and urge it to the other of the open and closed states, and that the suction control device (43, 43') controls the application of reduced pressure to the valve member (105, 105') and thereby controls operation of the valve. A suction system according to Claim 6, characterised in that the system includes a suction control lumen (41, 41') extending between the suction control device (43, 43') and the side lumen (106), and that the suction control device (43, 43') includes an orifice (47, 47') that can be opened and closed by the user to control entry of air into the suction control lumen (41, 41') and thereby control the application of reduced pressure to the valve member (105). A suction system according to Claim 6 or 7, characterised in that the spring (107) urges the valve member (105) to an open state, that the side lumen (106) is connected to apply suction to urge the valve member (105) to a closed state, and that the suction control device (43) has a normally-closed orifice (47) that can be opened to allow air into the side lumen (106) so as to reduce the effect of the reduced pressure on the valve member (105) and allow the valve member (105) to be displaced to an open state. A suction system according to Claim 6 or 7, characterised in that the spring (107') urges the valve member (105') to a closed state, that the side lumen is connected to apply reduced pressure to urge the valve member (105') to an open state, and that the suction control device (43') has a normally-open orifice that can be closed to prevent air entering the side lumen so as to enable a reduced pressure to be applied on the valve member (105') and thereby allow the valve member to be displaced by the reduced pressure to an open state. A suction system according to any one of Claims 6 to 9, characterised in that the valve (100, 100') includes a recess (104, 104') along which the valve member (105, 105') is displaceable, that the side lumen (106) opens into one end of the recess such that reduced pressure applied by the vacuum source (2) via the side lumen (106) urges the valve member (105, 105') to the one end of the recess, and that a control lumen (41, 41') extends from the suction control device (43, 43') and opens into the one end of the valve recess (104, 104').

Inventors: DEVLIN THOMAS, ULRICH KARL, WILLIS FRANK, DEVLIN, THOMAS, ULRICH, KARL, WILLIS, FRANK
Applicants: SIMS PORTEX INC, SIMS PORTEX, INC.
Application year: 1993
Main classification: A61M1
IPC codes: A61M1