GB2468946A

GB2468946A - Closed system suction catheter assembly

Info

Publication number: GB2468946A
Application number: GB1002036A
Authority: GB
Inventors: Neil Steven Veasey
Original assignee: Smiths Medical International Ltd
Current assignee: Smiths Medical International Ltd
Priority date: 2009-03-26
Filing date: 2010-02-09
Publication date: 2010-09-29
Anticipated expiration: 2030-02-09
Also published as: GB201002036D0; GB0905219D0; GB2468946B

Abstract

A closed system suction catheter assembly has a suction catheter 20 extending between a suction control valve 30 and a patient end fitting 1 within a flexible envelope 23. The patient end fitting 1 has a flushing chamber 106 with an internal taper within which the patient end 22 of the catheter 20 is located when withdrawn. The flushing chamber 106 opens at its patient end via an opening 120 just large enough to allow passage of the suction catheter 20 and has a wiper seal 12 at the other end. The tip 22 of the suction catheter 20 is softer than the main part of the catheter to reduce trauma.

Description

SUCTION CATHETER ASSEMBLIES

This invention relates to suction catheter assemblies.

During intubated ventilation of a patient it is necessary periodically to remove secretions that collect in the respiratory passages or in the tracheal tube. A conventional suction catheter can be used for this purpose but it is usually preferred to use a closed system suction catheter assembly. A closed system assembly comprises a manifold at the patient end with a sliding, wiper seal through which a suction catheter can be advanced and withdrawn. A flexible envelope is joined at one end to the manifold and encloses the catheter along its length. The other end of the envelope and the catheter is joined with a machine end component including a suction control valve and a connector. The connector connects the catheter to a suction source; the valve enables the clinician to control the suction applied by the catheter. Examples of closed system suction catheters are described in US5269728, US5300043, US4569344, US4638539, US4872579, US5 167622, US5779687, US5325850, US5490503, US54 19769, US54606 13, US5349950, GB2394761, GB2400160, US6109259, US6227197, EP801577B, W096/09082, EP12399O7B, EP1478424B, US6588427, EP1620148B, US2004/0221852, EPI91 1482A, EP1795217A, US2007/0282250, W02007/143502, US2008/0188833, US6227200, US6543451, EP1239909B, US6602219, EP1347798, W002/49680, US6609520, WO/055 143, US6805125, US6923 184, US7O21313, US7191782, W02004/101045, US7263997, W02004/103448, W000/15276, EP637257B, EP1113835B, EP1210957A, EP1237612B, US7152603, EP1267957B, US6978783, US2004/0007236, US2005/021 1253, US2005/021 1245, US200510235987, US7059322, W02004/032817, US2008/0135051, US4836199, US4850350, US4967743, US5025806, US5083561, US5220916, US5215522, US5255676, US5277177, US5309902, US5333606, US5343857, US5487381, US55 13628, US5791337, EP1343552A, W002/49699, US6612304, EP1322371A, W002/28463, US6629530, W002/051485, US6769430, EP1330284, W002/36191, US6886561, W02004/034946, US7188623, W02006/014431, US7341059, W02005/094925, W02006/103233, W02007/030388, W02009/003135, US4838255, US5107829, US5133345, US5642726, US6702789, US7458955, US7273473, US5139018, US4327723, US45 15592, US6099519, EP695556B, US5065754, US5730123, US5207220, US5309903 and US7086402. Closed system suction catheters are available from various manufacturers including Smiths Medical, Kimberley Clark, Covidien and Viasys.

The patient end coupling of the suction catheter assembly may include provision for irrigating or flushing the suction catheter when it is withdrawn from the tracheal tube.

The coupling includes an irrigation port close to the wiper seal by which a flushing fluid, such as saline, can be supplied to a flushing chamber forwardly of the wiper seal. The flushing fluid enters the flushing chamber and is sucked along the catheter to help flush away any material that may have collected in its bore. The patient coupling may include a manually-operable isolation valve to prevent washing fluid flowing into the patient's

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respiratory passages. It can be desirable, especially in paediatric patients, to be able to introduce medication, such as a surfactant, into the respiratory passages. This can be difficult with paediatric patients because the very small diameter of the tracheal tube used with such patients severely restricts the passage of aerosol medication. In some prior closed system suction catheters it is necessary to disconnect the suction catheter assembly from the tracheal tube when different functions need to be carried out, or it may be necessary to connect an adaptor to the patient end fitting. It is undesirable in medical applications to supply instruments with many different, separate components because the need to assemble the components introduces complication and delay, and complicates safety auditing of instruments used during surgery.

It is an object of the present invention to provide an alternative suction catheter assembly.

According to one aspect of the present invention there is provided a closed system suction catheter assembly including a patient end fitting at one end adapted to be attached to the machine end of a tracheal tube, a machine end fitting at an opposite end, a suction catheter extending from the machine end fitting through a wiper seal at a machine end of a flushing chamber in the patient end fitting such that the patient end of the suction catheter locates within the flushing chamber on the patient side of the wiper seal when the catheter is retracted into the flexible envelope, a protective, flexible envelope extending around and along the suction catheter and attached to the machine end fitting at one end and to the patient end fitting at the other end, the suction catheter having a patient end tip portion that is softer than the main portion of the catheter and the flushing chamber being provided with an opening of restricted size at its patient end without a wiper seal so that the soft tip of the catheter can be extended out of the flushing chamber through the opening without substantial deformation.

According to another aspect of the present invention there is provided a method of cleaning a suction catheter extending within a protective envelope comprising the steps of pulling the catheter through a wiper seal at one end of a flushing chamber such that material collected on the outside of the catheter is wiped off into the flushing chamber, the catheter being pulled through an opening at an opposite end of the flushing chamber until its patient end passes through the opening and locates within a tapering region of the flushing chamber, and supplying a flushing liquid to the flushing chamber while applying suction to the catheter such that the wiped material is flushed into the tapering region and sucked along the bore of the catheter.

According to a further aspect of the present invention there is provided a closed system suction catheter assembly including a patient end fitting adapted to be attached to the machine end of a tracheal tube, a machine end fitting at an opposite end, a suction catheter extending from the machine end fitting through a wiper seal in the patient end fitting and a protective, flexible envelope extending around and along the suction catheter and attached to the machine end fitting at one end and to the patient end fitting at the

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other end, the patient end fitting including a ventilation port by which ventilation gas can flow to the patient, a flushing chamber extending from the wiper seal and an irrigation port opening into the flushing chamber, the flushing chamber having an internally tapering portion extending along a major part of its length with an opening at its patient end through which the suction catheter can be extended and withdrawn, the diameter of the opening being substantially the same as the external diameter of the suction catheter.

A closed system suction catheter assembly for paediatric use and its method of operation, according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation view of the assembly; Figure 2 is an enlarged perspective view of the patient end fitting in section along a plane aligned with the axis of the fitting and the axis of an irrigation port; and Figure 3 is an enlarged perspective view of the patient end fitting in section along a plane aligned with the axis of the fitting and of an access port.

With reference first to Figure 1, the assembly includes a forward or patient end manifold coupling 1 having a first port 10 adapted to connect to a standard 15mm or 8.5mm tracheostomy/tracheal connector 2 of the kind fitted to the machine end of a paediatric tracheal tube 3. The rear, machine end of the connector 2 is closed apart from a relatively small bore, so that it fills the space within a cooperating female connector and thereby minimizes deadspace. At the opposite end of the coupling 1 and aligned with the first port 10 is a second port 11 containing a wiper seal 12 through which the suction catheter 20 can be extended and withdrawn. The coupling 1 has three further ports 13 to 15, which are described in detail later.

The suction catheter 20 is flexible, typically being 300 to 500mm long and having an external diameter of about 1.5mm to 5mm. The rear, machine end 21 of the catheter 20 is connected to a suction control valve 30 of the kind described in GB2400 160 and this is connected to a conventional suction source 4. The tip or forward end 22 of the catheter 20 locates just forwardly of the seal 12 in the patient end coupling 1. The tip 22 is preferably softer than the main part of the catheter 20 rearwardly of the tip so as to reduce trauma during use where it might contact delicate paediatric tissue. The soft tip 22 may be provided in various ways but is preferably made by attaching a short length of a softer material to the forward end of the shaft of the catheter 20. The soft tip 22 is preferably attached by RF welding in a mould. A flexible, protective envelope 23 extends around and along the catheter 20, being joined at its forward end to the coupling 1 and at its rear end to the suction control valve 30. The flexible nature of the envelope 23 enables the catheter 20 to be manipulated through the envelope to allow it to be pushed forwardly or pulled rearwardly through the seal 12. The length of the envelope 23 is chosen to prevent the forward end 22 of the catheter 20 being pulled through the seal 12.

With reference now also to Figures 2 and 3, the patient end fitting 1 is a unitary, one-piece integral moulding from a rigid transparent plastics material, such as ABS. The fitting I has a main body portion 100 of tubular shape and circular section, being about 50mm long and 20mm in diameter externally at its patient end. The inside of the forward, patient end of the body portion 100 provides the first port 10 in the form of a 15mm or 8.5mm female tapered connector. This connector portion 10 extends for about 16.5mm.

About midway along the body portion 100 a single ventilator port 13 projects rearwardly at an angle a of about 60° to the axis of the body portion. The open end of this port 13 has a male taper adapted to receive a standard 15mm or 8.5mm female connector connected to a conventional ventilation circuit (not shown). Alternatively, the port 13 may be left open to atmosphere where the patient is breathing unaided. Alternative patient fittings may include two ventilator ports, one for supplying gas to the patient and the other for taking exhaled gas away from the patient. The interior of the ventilator port 13 opens into the interior of body portion 100 and the patient end port 10 so that gas flows directly between the two ports. The patient and ventilation ports 10 and 13 could include swivel couplings.

The rear, machine end port 11 has a slightly smaller external diameter than the patient end port 10 and receives a collet 101 on its outside under which the patient end of the envelope 23 is trapped. The collet 101 is bonded onto the body portion 100 such as by means of a solvent or by a heat bond. The collet 101 has an inturned lip 102 that traps and retains the wiper seal 12 fitted into the machine end port 11. The seal 12 is moulded from an elastomeric material and has a short cylindrical bore 104 close to its patient end, the diameter of which is slightly smaller than the external diameter of the suction catheter 20 so that the catheter can be slid through the bore as a wiping seal. This prevents or reduces flow of gas past the seal 12 into the interior of the envelope 23 and also helps wipe any material from the outside of the catheter 20 as it is pulled back through the seal. The forward cylindrical bore 104 at the patient end opens into a rear flared portion 105, which helps guide the patient end 22 of the suction catheter 20 into the forward bore. The seal 12 forms the rear end of a flushing or irrigation chamber 106. The major part of the length of the flushing chamber 106 is provided by a tapering frusto-conical portion 107.

The portion 107 extends forwardly from a location just in front of the seal 12 by about 20mm. The tapering portion 107 tapers at an angle 0 of about 30° from an internal diameter of about 10mm adjacent the seal 12 for a length of about 16mm. At its forward, patient end, the passage through the tapering portion 107 continues through a restricted portion 120 provided by a cylindrical central portion 121 and tapered opposite end portions 122 and 123. The diameter of the central portion 121 is selected according to the diameter of the suction catheter 20 being used, being slightly larger than the catheter so that it can slide freely through it in an unrestricted manner. A cylindrical extension 125 projects forwardly from the central portion 121 to a position just forwardly of the opening of the ventilation port 13 into the interior of the main body portion 100. The extension has a constant diameter, smaller than the internal diameter of the connector portion 10, so that an annular recess 126 is formed between the outside of the extension and the inside of the connector portion. The ventilation port 13 opens into the extension 125 close to its forward, patient end.

A small diameter flushing or irrigation port 14 (Fig 2) projects externally, vertically from the body portion 100 and opens into the interior of the flushing chamber 106 adjacent the seal 12. The flushing port 14 is normally closed by a removable tethered cap (not shown) or, alternatively, by a valve.

The patient end fitting 1 is completed by the fifth port 15 (Fig 3), which takes the form of a general purpose access port. The port 15 is provided by a small diameter tubular extension projecting externally from about midway along the length of the body portion 100 and angled rearwardly at an angle f3 of about 30° to the axis of the body portion. The access port 15 is located in the same plane as the ventilation port 13 but on the opposite side of the body portion 100. The access port 15 opens into the interior of the body portion 100 via the tubular extension 125, opening into the extension opposite the ventilation port 13 opening. When not in use, the access port 15 is closed by a removable, tethered cap (not shown).

The fitting 1 also has a magnifying viewing window 110 (Fig 2) moulded in the wall of the body portion 100 as a transparent region with a concave external surface to afford some viewing enlargement. The window 110 is located over the restricted portion in two regions on opposite sides of the fitting so that it can be viewed from either side. In this way, the clinician is able to view markings on the suction catheter 20 where it passes through the restricted portion 120.

In use, the patient end coupling 10 of the fitting 1 is connected to the 15mm male connector 2 attached to the machine end of the paediatric tracheal tube 3 and the ventilation port 13 is connected to a ventilation circuit (not shown) of conventional kind.

The suction assembly can remain attached to the tracheal tube 3 without impeding ventilation. In its normal state, the suction catheter 20 is fully retracted within the envelope 23 with its tip 22 located in the flushing chamber 106 and with the flushing and access ports 14 and 15 capped. When suctioning is required, the clinician grips the suction catheter 20 through the envelope 23 and pushes it forwardly through the wiper seal 12 and through the restriction 120 at the forward end of the flushing chamber 106.

Continued advancement causes the tip 22 of the catheter 20 to enter the tracheal tube connector 2 and the tracheal tube 3 itself. The clinician actuates the valve 30 to start suctioning as soon as the tip 22 of the catheter 20 enters the tracheal tube 3, while viewing the extent of insertion through the window 110. When suctioning has been completed, the suction catheter 20 is pulled back until its tip 22 is just inside the flushing chamber 106. The wiping action of the seal 12 causes material collected on the outside of the catheter 20 to be wiped off into the flushing chamber 106. This material is removed by uncapping the flushing port 14 and dispensing a small quantity of saline into the flushing chamber 106, such as from a syringe, while suction continues to be applied through the catheter 20. The saline flows into the chamber 106, dissolving and loosening the wiped secretions, which are then drawn through the bore of the suction catheter 20.

The flow of fluid along the bore of the catheter 20 also helps clean this bore and reduce the build up of bacteria in the catheter.

The tapering shape of the flushing chamber 106 is chosen to minimise escape of the flushing liquid out of the patient end of the chamber. The relatively narrow taper of about 30° and the close fit of the catheter 20 within the restricted portion 120 forms a narrow clearance between the tip 22 of the catheter and the inside surface of the flushing chamber 106 along at least the forward half of the chamber. This causes any fluid flowing forwardly along the chamber 106 to pass close to the tip 22 of the catheter 20, thereby ensuring that it is sucked into the catheter by the applied suction. In this way, cleaning can be carried out in an efficient manner with little escape of flushing liquid into the patient, which is particularly important in paediatric applications. The arrangement of the present invention avoids the need to provide a valve to close the flushing chamber although a valve could be used in addition for extra restriction of the escape of flushing liquid.

The present arrangement also has the advantage of avoiding the need for any manually-operated isolation valves of the kind used in some prior assemblies, which add to the cost and complexity of such assemblies and make their use more complicated. The efficient cleaning possible with the present arrangement enables the assembly to be used safely on the same patient for up to around 72 hours before replacement is needed. The absence of a wiping seal with the suction catheter 20 at the forward end of the flushing chamber 106 reduces the amount of secretions on the outside of the catheter that are wiped off the catheter outside the flushing chamber when the catheter is retracted. Also, the absence of a wiping seal at the forward end of the flushing chamber 106 enables the suction catheter 20 to have a soft tip 22 without the risk that this would be damaged or defonned by having to be forced through a wiper seal. It will also be appreciated that if a soft tip catheter were used with a wiper seal such that the tip had to be pushed through the seal there would be a risk that the tip would fold over and impede passage through the seal, making extension of the catheter difficult.

The access port 15 can be used for various functions such as monitoring, sensing, gas sampling or the introduction of substances such as gas, vapour, aerosols, humidified gas or the like. The angled orientation of the port 15 also enables it to be used to introduce a secondary catheter or tube into the tracheal tube 3 since the angle of the port ensures that such a catheter or tube will be directed towards the tracheal tube 3 without kinking or catching on surface formations within the patient end fitting 1. Where

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medication or other treatment agent needs to be administered to the respiratory passages of an adult this can be achieved by dispensing the medication in aerosol form into the machine end of the tracheal tube. In paediatric applications, however, the diameter of the tracheal tube is much smaller and any attempt to administer aerosol medication in the same way, at the machine end, would result in loss of the majority of the medication by collection on the inside surface of the tracheal tube. This would lead to unreliable or insufficient dosing. Instead, in such paediatric applications it is usual practice to disconnect the suction catheter assembly and to connect an adaptor between the tracheal tube and the ventilation system that enables a small-bore catheter to be extended along the tracheal tube. Medication can then be dispensed from the patient end of this catheter when it is located beyond the patient end of the tracheal tube. This ensures that all the medication or treatment agent dispensed reaches the desired location. In the present arrangement, however, a treatment agent delivery catheter 130 can be inserted into the tracheal tube 3 without the need to interrupt ventilation and without the need for additional components. The access port 15 built in to the patient end fitting I is simply uncapped and the patient end of the delivery catheter 130 is pushed through the port, the angle of the port directing the catheter into the connector 2 and into the tracheal tube 3 itself. The catheter 130 is advanced along the tracheal tube 3 until its tip 131 is level with or projects slightly beyond the patient end of the tracheal tube. The clinician then administers the medication or other treatment agent (most usually in the case of paediatric patients the agent is a surfactant) to the machine end of the delivery catheter 130 50 that it flows along the catheter and sprays out of its patient end 131 into the patient's respiratory passages. The clinician then pulls the delivery catheter 130 rearwardly out of the port 15, which can then be recapped.

Although the above invention is described for paediatric application where it has particular advantages, it can be seen that it could also be used in adult applications.

Claims

CLAIMSA closed system suction catheter assembly including a patient end fitting at one end adapted to be attached to the machine end of a tracheal tube, a machine end fitting at an opposite end, a suction catheter extending from the machine end fitting through a wiper seal at a machine end of a flushing chamber in the patient end fitting such that the patient end of the suction catheter locates within the flushing chamber on the patient side of the wiper seal when the catheter is retracted into the flexible envelope, a protective, flexible envelope extending around and along the suction catheter and attached to the machine end fitting at one end and to the patient end fitting at the other end, wherein the suction catheter has a patient end tip portion that is softer than the main portion of the catheter and the flushing chamber is provided with an opening of restricted size at its patient end without a wiper seal so that the soft tip of the catheter can be extended out of the flushing chamber through the opening without substantial deformation.
2. A method of cleaning a suction catheter extending within a protective envelope comprising the steps of pulling the catheter through a wiper seal at one end of a flushing chamber such that material collected on the outside of the catheter is wiped off into the flushing chamber, the catheter being pulled through an opening at an opposite end of the flushing chamber until its patient end passes through the opening and locates within a tapering region of the flushing chamber, andSsupplying a flushing liquid to the flushing chamber while applying suction to the catheter such that the wiped material is flushed into the tapering region and sucked along the bore of the catheter.
3. A closed system suction catheter assembly including a patient end fitting adapted to be attached to the machine end of a tracheal tube, a machine end fitting at an opposite end, a suction catheter extending from the machine end fitting through a wiper seal in the patient end fitting and a protective, flexible envelope extending around and along the suction catheter and attached to the machine end fitting at one end and to the patient end fitting at the other end, the patient end fitting including a ventilation port by which ventilation gas can flow to the patient, a flushing chamber extending from the wiper seal and an irrigation port opening into the flushing chamber, wherein the flushing chamber has an internally tapering portion extending along a major part of its length with an opening at its patient end through which the suction catheter can be extended and withdrawn, the diameter of the opening being substantially the same as the external diameter of the suction catheter.
4. A closed system suction catheter assembly substantially as hereinbefore described with reference to the accompanying drawings.
5. Any novel and inventive feature as hereinbefore described.