AU2013202645B1

AU2013202645B1 - Oscillatory positive expiratory pressure apparatus

Info

Publication number: AU2013202645B1
Application number: AU2013202645A
Authority: AU
Inventors: Brendan John Hall
Original assignee: PHYSIOTHERAPYDYNAMICS Pty Ltd
Current assignee: PHYSIOTHERAPYDYNAMICS Pty Ltd
Priority date: 2012-08-14
Filing date: 2013-04-05
Publication date: 2013-09-05
Anticipated expiration: 2033-04-05
Also published as: WO2014026227A1

Abstract

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -27 Apparatus for providing oscillatory positive expiratory pressure therapy to a subject, the apparatus including: a hollow container defining an internal volume that contains a liquid in use; a fluid conduit having an inlet and an outlet in fluid communication with the internal volume, the outlet being provided at a position proximate to a base of the container; and a one-way exhalation valve configured to permit fluid flow into the internal volume via the fluid conduit and to substantially prevent fluid flow out of the internal volume via the fluid conduit, so that in use the subject can exhale into the liquid via the inlet. Fig. 1A

Description

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1. doc-5/04/2013 OSCILLATORY POSITIVE EXPIRATORY PRESSURE APPARATUS Background of the Invention [0001] The present invention relates to apparatus for providing oscillatory positive expiratory pressure therapy to a subject. Description of the Prior Art [0002] There are a range of medical conditions which may cause a patient to suffer retention of mucus (or other secretions) in their lungs and/or airways. Example conditions include cystic fibrosis and bronchiectasis, and post-operative patients may also suffer similar respiratory issues. The mucus can be difficult for the patient to clear from their lungs and airways without assistance, especially if their lungs are in a weakened state. [0003] One form of treatment which has proved effective in assisting a patient in clearing mucus from their lungs and airways is positive expiratory pressure (PEP) therapy. In its simplest form PEP therapy involves having the patient breathe out into a device which provides a resistance against the patient's expiration. This generates a positive pressure in the airways during expiration, which can assist the patient to clear their lungs and airways. [0004] Several types of PEP devices are known. One type of available PEP device is a PEP mask having an air passageway including a resistor valve which is used to provide the necessary resistance. However, PEP masks generally provide a constant positive pressure in the patient's airways, and whilst this can be effective, it has been found that an oscillatory positive pressure can more effectively assist in the dislodgement of retained mucus. [0005] So-called "bubble" PEP devices may be used to provide such an oscillatory positive pressure. Bubble PEP devices are generally involve having the patient blow bubbles in a volume of liquid, such as water, using tubing having an outlet submerged in the liquid. The static pressure of the column of liquid above the outlet provides a positive pressure in the patient's airways. When the patient breathes out vigorously, the created bubbles displace and disturb the liquid and result in oscillatory variations in the pressure.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -2 [0006] Bubble PEP devices are typically provided in a rudimentary manner. A common bottle of the type used for packaging milk, juice or the like can be cleaned and repurposed to hold the liquid, and a length of common flexible tubing can be inserted into the bottle to construct an improvised bubble PEP device which can be provided to a patient at low cost. [0007] The liquid is usually water, although soap can be added to allow bubbles to be more readily formed and colouring can be added, to add visual stimulation for paediatric patients. The level of pressure provided using the bubble PEP device can be adjusted by varying the level of the liquid in the bottle and/or the position of the tubing, although sometimes this is difficult to control since the tubing is usually not supported in a fixed position in the bottle. [0008] Such improvised bubble PEP devices have several downsides. They can be unhygienic, particularly if not cleaned regularly, and proper cleaning can be difficult when repurposed packaging bottles are used. Furthermore, there is a risk of the patient inhaling the liquid through the tube, particularly if the patient cannot reliably control their exhalation and inhalation, or if the patient is young and may attempt to drink the liquid. [0009] In view of these downsides, improvised bubble PEP devices have been deemed unsuitable for use in medical environments by at least one state health provider in Australia. Other available PEP devices such as PEP masks are comparatively expensive alternatives, and this can be problematic where patients may be required to obtain their own PEP device for continuation of care after discharge. Also, as discussed above, PEP masks do not typically provide the beneficial oscillatory positive pressure provided using bubble PEP devices. [0010] Accordingly, there is a need for a new means of providing oscillatory positive pressure therapy to a patient, which either mitigates one or more of the issues described above or at least provides a suitable alternative to currently available PEP devices. [0011] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

H:\tw\Interwoven\NRPortbl\DCC\TW\5278084_1. doc -3 Summary of the Present Invention [0012] In a first broad form the present invention seeks to provide an apparatus for providing oscillatory positive expiratory pressure therapy to a subject, the apparatus including: a) a hollow container defining an internal volume that contains a liquid in use; b) a fluid conduit having: i) an inlet; and, ii) an outlet in fluid communication with the internal volume, the outlet being provided at a position proximate to a base of the container, at least a portion of the fluid conduit being formed integrally with a wall of the container; and, c) a one-way exhalation valve configured to permit fluid flow into the internal volume via the fluid conduit and to substantially prevent fluid flow out of the internal volume via the fluid conduit, so that in use the subject can exhale into the liquid via the inlet. [0012A] Typically the fluid conduit includes a wall conduit portion formed integrally with the wall and a base conduit portion formed integrally with the base, the outlet being provided at an end of the base conduit portion [0013] Typically the apparatus further includes a breathing adaptor connected to the inlet via an inlet tube, so that the subject can exhale into the liquid and inhale using the breathing adaptor. [0014] Typically the breathing adaptor includes: a) a breathing opening that the subject breathes through in use; b) an exhalation opening connected to the inlet; c) an inhalation opening; and, d) a one-way inhalation valve configured to permit fluid flow into the breathing adaptor via the inhalation opening and to substantially prevent fluid flow out of the breathing adaptor via the inhalation opening, so that the subject can inhale via the inhalation opening when using the breathing adaptor. [0015] Typically the breathing adaptor includes a mouthpiece having the breathing opening.

H:\tw\Interwoven\NRPortbl\DCC\TW\5278084_L doc -4 100161 Typically the breathing adaptor includes an adaptor connector for allowing the breathing adaptor to be connected to a corresponding connector of at least one of: a) a breathing mask; b) a mouthpiece; and, c) a tracheostomy tube. [0017] Typically the breathing adaptor is formed as an assembly including: a) a mouthpiece part; and, b) a valve fitting part connected to the mouthpiece part, the valve fitting part including the inhalation opening and the inhalation valve. [0018] Typically at least a portion of the fluid conduit is formed from tubing. [0019] Typically the apparatus includes a tubing connector for allowing the tubing to be connected to the apparatus. [0020] Typically at least a portion of the fluid conduit is formed integrally with the container. [0021] Typically the fluid conduit extends inside the internal volume of the container. [0022] Typically the exhalation valve is positioned along the fluid conduit. [00231 Typically the exhalation valve is a ball valve provided in the fluid conduit. [0024] Typically the container includes a) a container body having an open end; and, b) a lid for closing the open end of the body. [0025] Typically the body includes a body conduit portion and the lid includes a lid conduit portion, the respective conduit portions being aligned when the lid closes the open end of the body and forming portions of the fluid conduit. [0026] Typically the lid includes a tubing connector coupled to the lid conduit portion. [00271 Typically the lid includes a first opening for allowing the fluid conduit to extend through the lid and a second opening for at least one of allowing the container to be filled H:\tw\lnterwoven\NRPortbl\DCC\TW\5278084_ .doc -5 with the liquid via the second opening and allowing fluids exhaled into the liquid by the subject to exit the internal volume. [00281 Typically the apparatus includes a cap for covering the openings in the lid. [0029] Typically the cap includes respective seals for sealing the openings in the lid. [0030] Typically the body includes one or more walls and a base. [0031] Typically at least a portion of the walls is at least partially transparent to allow visual determination of a level of liquid contained in the internal volume in use. [0032] Typically the walls include measurement markings for allowing measurement of the level of liquid contained in the internal volume with reference to the measurement markings. [00331 Typically the base is detachable from the walls. [0034] Typically the walls includes a wall conduit portion and the base includes a base conduit portion, the respective conduit portions being aligned when the base is attached to the walls and forming portions of the fluid conduit. [0035] Typically the outlet is provided at an end of the base conduit portion. [0036] Typically the outlet is positioned proximate a centre of the base. [0037] Typically the inlet acts as a connector to receive an inlet tube. [0038] In a second broad form the present invention seeks to provide a method for providing oscillatory positive expiratory pressure therapy to a subject, the method using an apparatus including: a) a hollow container defining an internal volume; b) a fluid conduit having an inlet and an outlet in fluid communication with the internal volume, the outlet being provided at a position proximate to a base of the container, at least a portion of the fluid conduit being formed integrally with a wall of the container; and, H:\tw\Interwoven\NRPortbl\DCC\TW\5382908_ 1.doc-5/04/2013 -5A a) a one-way exhalation valve configured to permit fluid flow into the internal volume via the fluid conduit and to substantially prevent fluid flow out of the internal volume via the fluid conduit, wherein the method includes: i) at least partially filling the internal volume of the container with a liquid; and, ii) having the subject exhale into the liquid via the inlet.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1. doc-5/04/2013 -6 Brief Description of the Drawings [0039] An example of the present invention will now be described with reference to the accompanying drawings, in which: [0040] Figure 1A is a schematic representation of an example apparatus for providing oscillatory positive expiratory pressure when used by a subject; [0041] Figure 1B is a schematic representation of the apparatus of Figure 1A in use; [0042] Figure IC is a schematic representation of the apparatus of Figure 1A further including a mouthpiece; [0043] Figure ID is a schematic representation of the apparatus of Figure IC in use; [0044] Figure 2A is a schematic perspective view of an example embodiment of the apparatus of Figure 1A; [0045] Figure 2B is a schematic perspective cutaway view of the container of Figure 2A; [0046] Figure 2C is a schematic perspective cutaway view at Detail C of Figure 2B; [0047] Figure 2D is a schematic perspective cutaway view at Detail D of Figure 2B; [0048] Figure 3A is a schematic perspective cutaway view of a body of the apparatus of Figure 2A; [0049] Figure 3B is a schematic perspective cutaway view at Detail B of Figure 3A; [0050] Figure 4A is a schematic perspective view of a base of the apparatus of Figure 2A; [0051] Figure 4B is a schematic top view of the base of Figure 4A; [0052] Figure 4C is a schematic side cross-section view of the base of Figure 4A; [0053] Figure 5A is schematic perspective view of an example of a lid of the apparatus of Figure 2A; [0054] Figure 5B is a schematic perspective view of a rear of the lid of Figure 5A; [0055] Figure 5C is a schematic perspective view of an underside of the lid of Figure 5A; [0056] Figure 5D is a schematic top view of the lid of Figure 5A; [0057] Figure 5E is a schematic side cross-section view of the lid of Figure 5A; [0058] Figure 5F is a schematic bottom view of the lid of Figure 5A; [0059] Figure 6A is a schematic perspective view of a cap of the apparatus of Figure 6A; [0060] Figure 6B is a schematic top view of the cap of Figure 6A; [0061] Figure 6C is a schematic side cross-section view of the cap of Figure 6; H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -7 [0062] Figure 7A is a schematic perspective view of a breathing adaptor for use with the apparatus of Figure 2A; [0063] Figure 7B is a different schematic cutaway perspective view of the breathing adaptor of Figure 7A; [0064] Figure 8A is a schematic perspective view of a mouthpiece of the breathing adaptor of Figure 7A; [0065] Figure 8B is a schematic end view of the mouthpiece of Figure 8A; [0066] Figure 8C is a schematic side view of the mouthpiece of Figure 8A; [0067] Figure 8D is a schematic side cross-section view of the mouthpiece of Figure 8A; [0068] Figure 9A is schematic perspective view of a valve fitting of the breathing adaptor of Figure 7A; [0069] Figure 9B is a different schematic perspective view of the valve fitting of Figure 9A; [0070] Figure 9C is a schematic perspective cutaway view of the valve fitting of Figure 9A; [0071] Figure 9D is a schematic end view of a first end of the valve fitting of Figure 9A; [0072] Figure 9E is a schematic end view of a second end of the valve fitting of Figure 9A; [0073] Figure 10A is a schematic perspective view of another example of a breathing adaptor for use with the apparatus of Figure 2A; and, [0074] Figure 1 OB is a different schematic cutaway perspective view of the breathing adaptor of Figure 10A. Detailed Description of the Preferred Embodiments [0075] An example apparatus 100 for providing oscillatory positive expiratory pressure therapy to a subject S will now be described with reference to Figures 1A and 1B. [0076] In a broad form, the apparatus includes a hollow container 110 defining an internal volume 101, a fluid conduit 120, and a one-way exhalation valve 130. The container 110 contains a liquid L in use, as depicted in Figures 1A and 1B. [0077] The fluid conduit 120 has an inlet 121 and an outlet 122 in fluid communication with the internal volume 101. The outlet 122 is provided at a position proximate to a base 111 of the container 110.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -8 [0078] The one-way exhalation valve 130 is configured to permit fluid flow into the internal volume 101 via the fluid conduit 120 and to substantially prevent fluid flow out of the internal volume 101 via the fluid conduit 120. [0079] Accordingly, in use the subject S can exhale into the liquid L via the inlet 121, as shown in Figure 1B, in which the flow of fluid exhaled by the subject S is indicated using a series of arrows. When the subject S exhales into the liquid L, static pressure in the liquid L provides a resistance to the exhalation by the subject S. This generates a positive expiration pressure in the airways of the subject S, which can assist the subject S in clearing retained mucus or the like from the subject's lungs and airways. [0080] With reference to Figure 1B, it can be seen that the subject S exhales into the inlet 121 for example, via an inlet tube 123 coupled to the inlet 121, which acts as a connector for receiving the inlet tube 123. The exhalation valve 130 permits the exhaled fluid to flow through the fluid conduit 120. The exhaled fluid exits the fluid conduit 120 at the outlet 122 where it can form bubbles B in the liquid L. As the subject S exhales, the bubbles B generate disturbances in the liquid L, which can cause oscillation in the resistance the liquid L provides to the exhalation by the subject S. Thus, the apparatus can provide an oscillating positive expiration pressure in the airways of the subject S due to the disturbances caused through the formation of bubbles B in the liquid L. [0081] The one-way exhalation valve 130 allows the subject S to exhale into the liquid L, via the fluid conduit 120, but substantially prevents the subject from inhaling via the fluid conduit 120. Accordingly, the subject S will generally be unable to inhale the liquid L through the fluid conduit 120, which might otherwise occur if the exhalation valve 130 was not provided. This helps to ensure that the subject S does not accidentally inhale the liquid L as the subject S breathes in after an exhalation. [0082] It will be appreciated that the exhalation valve 130 can allow the apparatus 100 to be used by a subject S that does not have good control over their exhalation and inhalation, with a greatly reduced risk of inhaling the liquid L. The exhalation valve 130 can also help to prevent a subject S from drinking the liquid L via the fluid conduit 120, which may be attempted by a child or mentally incapacitated subject S.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -9 [0083] Since the subject S can only exhale through the fluid conduit 120, the subject S will typically inhale using different means. This can involve simply having the subject inhale from the surrounding environment, in between exhalations into the inlet 121. [0084] Alternatively, as depicted in Figures IC and ID, the apparatus 100 may further include an optional breathing adaptor 140 connected to the inlet 121, via the inlet tube 123, so that the subject S can exhale into the liquid L and also inhale using the breathing adaptor 140. [0085] In general, the breathing adaptor 140 may include a breathing opening 141 that the subject S breathes through (i.e. both inhales and exhales through) in use, an exhalation opening 142 connected to the inlet 121, via the inlet tube 123, and an inhalation opening 143. The inhalation opening 143 may simply be open to the surrounding environmental air, but may also be adapted to connect to a gas source, such as an oxygen tank or the like, as required. [0086] In one example, the breathing adaptor 140 further includes a one-way inhalation valve 150 configured to permit fluid flow into the breathing adaptor 140 via the inhalation opening 143 and to substantially prevent fluid flow out of the breathing adaptor 140 via the inhalation opening 143. Accordingly, the subject S can exhale via the exhalation opening 142 and into the liquid L via the inlet tube 123 and fluid conduit 120 as discussed above, and the subject can also inhale via the inhalation opening 142 when using the breathing adaptor 140, as depicted in Figure ID. [0087] When such a breathing adaptor 140 is provided in the apparatus 100, the subject S is able to perform complete respiration cycles using the breathing adaptor 140, without needing to inhale separately from the apparatus 100 and with a greatly reduced risk of inhaling the liquid L. [0088] The breathing adaptor 140 may include a mouthpiece for providing the breathing opening 141, such that the subject S can place the mouthpiece in their mouth and breathe through the mouthpiece in order to use the breathing adaptor 140.

H:\ ljr\Interwoven\NRPortbI\DCC\LJR\5017462 1.doc-5/04/2013 - 10 [0089] Alternatively, the breathing adaptor 140 may include an adaptor connector instead of a mouthpiece, the adaptor connector being configured to allow the breathing adaptor 140 to be connected to a corresponding connector of another breathing device, such as a breathing mask, a separate mouthpiece, a tracheostomy tube, or the like. [0090] It will be appreciated that the breathing adaptor 140 can allow a range of subjects S to use the apparatus 100 for providing oscillation positive expiratory pressure therapy, under a range of conditions. [0091] The fluid conduit 120 may be formed from tubing, such as flexible plastic tubing commonly used as breathing tubes for medical applications. Additionally or alternatively, at least a portion of the fluid conduit 120 may be formed integrally with the container 110. For example, the fluid conduit 120 extending between the inlet 121 and outlet 122 can be formed integrally with the container 110, and this can be beneficial in ensuring the outlet 122 of the fluid conduit 120 remains in a fixed position relative to the base 111 of the container 110. [0092] Examples of practical embodiments of elements of the apparatus 100 will now be described with reference to the Figures. [0093] An example of a container 110 for use with the apparatus 100 is shown in Figures 2A to 2D. In this example, the container 110 generally includes a container body having one or more walls 210 and a base 220 which collectively define the internal volume 101 for containing the liquid L in use. In this case the container body has a cylindrical shape and thus includes a single cylindrical wall 210 and a round base 220, although it will be appreciated that container bodies having different shapes can be used. [0094] Further details of the container wall 210 can be seen in Figure 3A and 3B and further details of the base 220 can be seen in Figures 4A to 4C, and particular features of the wall 210 and base 220 will be discussed in due course. [0095] The container body has an open upper end which can be closed by a lid 230 as shown in Figure 2A. Further details of the lid 230 can be seen in Figures 5A to 5F. [0096] In this example, the lid 230 includes a first opening 231 and a second opening 232. The first opening 231 is provided at an end of a lid conduit portion 233 extending through the H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 11 lid, as can be seen in Figure 2B and in further detail in Figure 2C. In use, the first opening 231 functions as the inlet 121 discussed above, and in one particular example further acts as a tubing connector to allow the inlet tubing 123 to be connected to the container 110. Thus, the inlet tubing 123 can be urged over the first opening 231, so that the inlet tubing 123 is held in place through frictional engagement with an outer surface of the lid conduit portion 233. [0097] As shown in Figure 2B, the second opening 232 extends through the lid 230 to allow fluid communication between the internal volume 101 of the container 110 and the surrounding environment outside the lid 230. The second opening 232 can allow the container 110 to be filled with the liquid L whilst the lid 230 closes the open end of the body. Furthermore, the second opening can allow pressure within the internal volume 101 to be equalised with the pressure in the surrounding environment to thereby prevent pressure from accumulating in the internal volume 101 due to fluids exhaled into the internal volume 101 by the subject S as the subject S exhales into the liquid L. Accordingly, exhaled fluid which forms bubbles in the liquid L is allowed to escape the internal volume 101 via the second opening 232 in use. Typically, the second opening 232 is significantly larger than the first opening 231 as shown in this example. [0098] The container 110 may also be provided with a cap 240 for covering the openings 231, 232 in the lid 230 when the container 110 is not in use. The cap includes first and second seals 241, 242 for sealing the opening 231, 231 in the lid 230 when the cap 240 is engaged with the lid 230. Accordingly, the seals 241, 242 are configured to align with and seal respective openings 231, 232 in use. Specifically, the first seal 241 is for sealing the first opening 231 and the second seal 242 is for sealing the second opening 232. Further details of the cap 240 are shown in Figures 6A to 6C. [0099] As shown in Figures 6A to 6C, the first seal 241 and the second seal 242 are interconnected by an elongated connecting member 243, and a further extension of the connecting member 243 is provided on one side of the first seal 241 in the form of an extension member 244 having an attachment ring 245 provided on a distal end. [0100] In this example, the attachment ring 245 is configured to allow the cap 240 to be attached to the lid 230 by having the attachment ring 245 engage with a groove 234 partially H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 12 surrounding the lid conduit portion 233. This groove 234 can be seen in closer detail in Figure 2C and can also be seen from a different angle in Figure 5B. [0101] At least the extension member 244 will typically be constructed of a resilient material such as rubber or a flexible plastic to allow the cap to be flexed between an open position as shown in Figure 5A and a closed position in which the seals 241, 242 seal the openings 231, 232 in the lid 230. It may be convenient to form the entire cap 240 from the same resilient material. [0102] As can be seen in closer detail in Figures 5A and 5D, the lid 230 may be provided with markings 501 on an external surface. These markings 501 may be used to indicate the functionalities of the respective openings 231, 232 to a subject S or a medical professional or carer providing the container 110 to the subject S. [0103] The markings 501 can also be used to provide a template for allowing details to be written on to the lid 230 by a subject S or a medical professional or carer. For example, the markings 501 may include fields for writing the name of the subject S, details of dates of the first use of the container 110, date of filling the container with liquid L, or any other pertinent information. Desirably, the fields will promote the recording of information for allowing tracking of the usage of the container 110 for ensuring that the hygiene of the container 110 is adequately maintained. [0104] In this example portions of the fluid conduit 120 provided with the container 110 are formed integrally with the side walls 210 and the base 220 of the container 110. As shown in Figure 2B, the integral portion of the fluid conduit 120 extends inside the internal volume 101 of the container 110, in the form of a wall conduit portion 211 extending along an internal surface of the wall 210 of the body and a base conduit portion 221 extending along an internal surface of the base 220. [0105] Each of the lid conduit portion 233, the wall conduit portion 211 and the base conduit portion 221 are aligned and connected together to effectively form a continuous portion of the conduit 130 extending between the conduit opening 231 at an end of the lid conduit portion 233 in the lid 230 to the outlet 122 provided at an end of the base conduit portion 221 in the base 220.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 13 [0106] In this example, the outlet 122 is positioned proximate to a centre of the base 220. This central positioning of the outlet 122 can result in the formation of bubbles B in the liquid L in use which float upwardly through the liquid L in a central location relative to the wall 210 of the container 110, which can help to promote increased disturbance in the liquid L due to the bubbles B. [0107] As shown in closer detail in Figure 2C, the one-way exhalation valve 130 may be positioned along the fluid conduit 120, and in this case the exhalation valve 130 is provided in the wall conduit portion 211 and is positioned at an upper end of the wall conduit portion 211 proximate to the connected lid conduit portion 233. [0108] In this example, the exhalation valve 130 is provided in the form of a ball valve arrangement having a ball 250 positioned inside the fluid conduit 120 in a ball housing 212 formed in the wall conduit portion 211. The ball housing 212, which is shown in closer detail in Figure 3B, provides an enlarged cavity inside the wall conduit portion 211 sized to retain the ball 250 inside. [0109] The ball 250 and the ball housing 212 cooperate to allow fluid to flow through the fluid conduit 120 in an exhalation direction so that the subject S can exhale into the liquid L, by having the ball 250 rest on a stop 213 at a first, lower end of the ball housing 212. Conversely, the ball 250 and the ball housing 212 cooperate to substantially prevent fluid flow through the fluid conduit 120 in a direction opposite to the exhalation direction. In the event the subject S attempts to inhale through the fluid conduit 120, the ball 250 will be drawn upwardly inside the ball housing 212 by suction generated as the subject S attempts to inhale, and this causes the ball 250 to engage with a shoulder 214 at a second, upper end of the ball housing 212 opposite to the aforementioned first end. When the ball 250 engages with the shoulder 214, this effectively closes the wall conduit portion 130. Additionally, the ball 250 may be formed of a material having a density less than that of the liquid, so that if fluid 101 flows up the conduit portion 211, the ball 250 will float on the liquid and be urged against the shoulder 214, thereby closing the wall conduit portion 130 and prevent egress of liquid through the inlet 121.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 14 [0110] The wall 210 and the base 220 forming the body of the container 110 can be provided as separate parts, which is the case in the present example. Accordingly, the wall 210 and the base 220 may be assembled together such that the wall conduit portion 211 and the base conduit portion 221 align to form a continuous portion of the fluid conduit 120. It will be appreciated, however, that the wall 210 and the base 220 can be integrally formed in other examples. [0111] The parts of the container 110 may be formed from a suitable plastic material. In a preferred embodiment, the parts of the container 110 are formed from a poly lactic acid (PLA) plastic, which may be formed from corn starch, and may be biodegradable, to allow the container 110 be disposable with a reduced impact to the environment following disposal. [0112] The wall 210 may be fixed to the base 220 by any known attachment means, such as by using an adhesive or fasteners, or by fusing the respective parts together, for example by welding a lower rim 310 of the wall 210 (as seen in Figure 3A) to a corresponding rim 410 of the base 220 (as seen in Figures 4A to 4C), in order to provide a combined effective body part including the walls 210 and the base 220. [0113] In one example, the base 220 may be removably attached to the wall 210, for example by providing a snap or interference fit connection, or a threaded connection. This can allow the base 220 to be detached to facilitate cleaning of the base conduit portion 221 and the wall conduit portion 211. It will be appreciated that the separate wall 210 and base 220 in this example each only include generally straight portions of the fluid conduit 120 which can greatly assist in cleaning. The base 220 should be fitted to the wall 210 in such a way as to ensure that an end 222 of the base conduit portion 221 opposite to the end having the outlet 121 is aligned with a corresponding end 215 of the wall conduit portion 211. [0114] Similarly, the lid 230 may be attached to the wall 210 in either a permanent or a removable manner. In one example, an annular rim 510 of the lid 230 (as seen in Figures 5A to 5C) may be fixed to an upper rim 320 of the wall 210 (as seen in Figure 3A) using a similar technique as discussed above for fixing the base 220 to the wall 211. [0115] In another example, the lid 230 and wall 210 may be configured to allow removal of the lid 230. Accordingly, the lid 230 may be removably attached to the wall 210 using known H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 15 techniques, such as a snap or interference fit, or a threaded connection. The lid 230 should be fitted to the wall 210 in such a way as to ensure that the lid conduit portion 233 aligns with the wall conduit portion 211 to form a continuous portion of the fluid conduit 120. [0116] It may be desirable to permanently fix together all of the parts of the container 110 including the wall 210, the base 220 and the lid 230 to provide an effectively unitary container 110 which can not be disassembled. [0117] In one example, the parts of the container 110 may be sterilised before or after they are assembled and the entire container 110 may be provided in a sterile packaging for use. Accordingly, when a container 110 is required for use in the apparatus 100, the container 110 can be removed from its sterile packaging in a sterile state. The container 110 can then be used for as long as it is hygienic to do so and may be subsequently disposed of, without requiring any cleaning processes. In this regard, it will be appreciated that by marking the container 110 with a subject's details and allowing the apparatus to be sealed using the cap 240, this in turn allows the apparatus to be reused a number of times by the same subject, without the risk of contamination of other subjects. [0118] The container 110 may be constructed from relatively inexpensive materials such as moulded plastic, to provide a relatively cheap and disposable container 110 which would not need to be cleaned. Alternatively, the container 110 may be constructed using more expensive materials and/or manufacturing techniques to provide a more durable container 110 which can allow repeated cleaning processes and/or repeated assembly and disassembly if the parts of the container 110 are not permanently fixed together. [0119] Desirably, at least a portion of the wall 210 of the container 110 may be at least partially transparent to allow a visual determination of the liquid L contained in the internal volume 101 whilst the container 110 is in use. The wall 210 may be constructed of a transparent material such as a clear plastic. [0120] The base 220 and the lid 230 need not be provided in the same transparent material and may be formed from a different opaque plastic material which is able to be joined to the transparent material forming the walls 210. However, the same material can be used to form each of the parts of the container 110. The wall 210 may be formed to include distinct opaque H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 16 and transparent portions, for example by providing a transparent window extending upwardly along the length of the wall 210, rather than forming the entire wall 210 from a transparent material. [0121] An at least partially transparent portion in the wall 210 can allow the subject S to see the bubbles B as they are formed in the liquid L inside the internal volume 101. A detergent may be added to the liquid L to promote the formation of longer lasting bubbles B on the surface of the liquid L which can add visual stimulation to the use of the apparatus 100. Similarly, a dye may be added to the liquid L to change the colour of the liquid L and further increase the visual stimulation effect. [0122] The at least partially transparent portion in the wall also allows the subject S, or a medical practitioner or carer, to obtain a visual indication of the level of the liquid L in the internal volume 101. In one example, the walls 210 may also include measurement markings for allowing measurement of the level of the liquid L contained in the internal volume 101 with reference to the measurement markings. [0123] It will be appreciated that the static pressure at the outlet 122 which in turn provides the positive expiratory pressure experienced by the subject S will be determined based on the level of the liquid L in the container 110. Accordingly, by filling the container 110 with liquid L to a predetermined level using the measurement gage markings, the level of positive expiratory pressure can be controlled and measured more accurately. The fixed positioning of the outlet 122 in the base 220 of the container 110 further helps to prevent variation in the relative difference between the surface of the liquid L and the outlet 122 which might otherwise impact on the accuracy of determining the pressure based on the level of the liquid L in the container 110. [0124] An example of a breathing adaptor 140 will now be described with reference to Figures 7A and 7B. In this example, the breathing adaptor 140 includes a mouthpiece part 710 configured to allow the subject S to breathe into the breathing adaptor 140 through the breathing opening 141 formed in the mouthpiece part 710, and a valve fitting part 720 connected to the mouth piece part 710.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 17 [0125] The valve fitting part 720 includes the inhalation opening 143 and the inhalation valve 150 as discussed above. The valve fitting part 720 further includes the exhalation opening 142 which in this case is provided via an adaptor tubing connector 721 extending from the valve fitting part 720. The tubing connector 721 is configured to allow connection of the inlet tubing 123 to the breathing adaptor 140 such that the inlet tubing can be used to connect the breathing adaptor 140 to the container 110. [0126] Further details of the mouthpiece part 710 can be seen in Figures 8A to 8D. The mouthpiece part 710 includes a body 810 which defines an internal passageway 801 between a first end 811 providing the breathing opening 141 for interfacing with the mouth of the subject S and a second end 812 for connection to the valve fitting part 720. [0127] Turning to Figures 9A to 9E, which show further details of the valve fitting part 720, the inhalation valve 150 in the valve fitting part 720 is provided in the form of a check valve which is adapted to close the inhalation opening 143 during exhalation by the subject S but to open the inhalation opening 143 as the subject inhales and generates suction which acts on the check valve. [0128] The tubing connector 721 is connected to a main body 910 of the valve fitting part 720, such that when the subject S exhales and the inhalation valve 150 prevents exhaled fluids from exiting the valve fitting part 720 via the inhalation opening 143, the exhaled fluids are instead allowed to flow from the valve fitting part 720 into the inlet tubing 123 via the tubing connector 721. [0129] Accordingly, as can be seen in Figure 9C, the valve fitting part 720 include a main passageway 901 extending through the main body 910 between a first end 911 for connection to the mouthpiece part 710 and a second end 912 providing the inhalation opening 143, and an exhalation passageway 902 which is in fluid communication with the main passageway 901 and extends through the tubing connector 721 to the exhalation opening 142. [0130] It will be appreciated that the breathing adaptor 140 may be provided in a range of different configurations yet provide functionalities similar to those discussed above. In order to illustrate some possible variations, another example of a breathing adaptor 1000 having a different shape compared to the previous example is shown in Figures 1OA and 1OB.

H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 18 [0131] In a similar fashion to the previous example, the breathing adaptor 1000 includes a mouthpiece part 1010 which provides a breathing opening 141, and a valve fitting part 1020 which provides the inhalation opening 143 and the exhalation opening 142. The use of separate parts for the mouthpiece part 1010 and the valve fitting part 1020 allows parts to be replaced or cleaned separately as required for hygienic purposes, maintenance, or the like. [0132] One difference in this example, compared to the previous example, is that a first end 1011 of the mouthpiece part 1010 is wider in a first direction than in a perpendicular second direction, so as to define a generally oval-shaped breathing opening 141 as can be seen in Figure 10A. This breathing opening 141 shape may improve comfort when a subject S uses the breathing adaptor 1000 and may aid in ensuring a good seal between the mouth of the subject S and the breathing opening 141. [0133] The valve fitting part 1020 has a generally similar functionality as the example previously described, in that the inhalation valve 150 allows air to enter through the inhalation opening 143 as the subject S inhales through the breathing opening 141 yet prevents air from exiting the inhalation opening 143 and instead causes air exhaled by the subject S to exit through the exhalation opening 142 via a tube connector 1021. [0134] However, as best seen in Figure 10B, in this case the tubing connector 1021 is of a relatively larger diameter compared to that of the previous example, and the terminating end of the tubing connector 1021 which provides the exhalation opening 142 does not protrude beyond the inhalation opening 143. In this example, the tubing connector 1021 is configured to receive the inlet tube 123 internally such that an outer wall of the inlet tube 123 engages with an inner wall of the tubing connector 1021. This can help to prevent restriction of the effective internal diameter available for airflow though the inlet tube 123 and the tubing connector 1021. [0135] It will be appreciated that a similar design approach may also be taken for other tubing connections, such as the connection of the other end of the inlet tube 123 to the lid 230 of the container 110. In particular, in some examples, the fluid conduit opening 231 of the lid 230 may be configured to receive and engage with an end portion of the inlet tube 123 so as to minimise airflow restrictions in the connection between the inlet tube 123 and the lid H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 19 conduit portion 233. The lid conduit portion 233 may be configured to have the same inside diameter as the inlet tube 123, with the fluid conduit opening 231 being enlarged sufficiently to accommodate the tubing wall thickness. [0136] It will be understood that suitable forms of the apparatus 100 may include numerous other variations in the shape and configuration of other elements compared to the previously discussed examples. For example, significant alterations in the size and shape of the container 110 may be possible whilst still allowing similar functionality. [0137] A range of different inlet tube 123 sizes may also be used, although it will be appreciated that the inside diameter of tubing used to provide the inlet tube 123 will generally dictate its capacity for airflow. Whilst the inside diameter of tubing used in the apparatus 100 is not particularly limited, an inside diameter of 8 mm or greater may be preferable because this has been found to allow improved airflow when the apparatus 100 is used by a subject S. In this regard, clinical studies have shown that the use of 8 mm inside diameter tubing for the inlet tube 123 provides significantly reduced airflow resistance compared to tubing having a smaller insider diameter. [0138] It will be understood that the sizes of other components which are used to supply air to or receive air from the inlet tube 123 in use will typically be provided with corresponding inside diameter dimensions, so as to reduce airflow resistance throughout the path of the air exhaled by the subject S. Accordingly, in one example in which the inlet tube 123 has an inside diameter of about 8 mm, the fluid conduit 120 and at least the tubing connector 1021 of the breathing adaptor 140, 1000 components will preferably have an insider diameter of about 8 mm, or greater. [0139] A practical example of usage of the apparatus 100 including the container 110 and the breathing adaptor 140 as described above will now be outlined. This example assumes that the container 110 is packaged in a sterilised manner as discussed above, with the cap 140 being used to seal the openings 131,132 in the lid 130. [0140] When it is determined that a subject may benefit from oscillatory positive expiratory pressure therapy, a medical professional or carer can obtain a packaged container 110 and remove the container 110 from its sterilised packaging. The cap 140 can then be removed H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 -20 from its sealing position so that the openings 131,132 are open. The cap 240 may remain attached to the container 110 using the attachment ring 245 as discussed above. [0141] A liquid L, usually water, can then be added to the container 110 using the second opening 232. A desired level of liquid L can be provided by measuring the level through a transparent portion of the wall 210 and with reference to measurement markings provided on the walls 210 as discussed above. After the container 110 is filled with liquid L, the container 110 should be maintained in an upright position such that the openings 231, 232 of the lid 230 are positioned at the top of the container 110. [0142] Inlet tubing 123 can then be attached to the container at the fluid conduit opening 231. The tubing may engage with the groove 234 surrounding the lid conduit portion 233. The tubing may also be provided in the same sterile packaging along with the container 110, or may be obtained separately, by using common tubing commonly used in medical situations. [0143] Typically the subject S will be provided with instructions on use of the apparatus 100 before therapy commences. [0144] If the subject S is deemed competent to use the apparatus 100 without a breathing adaptor 140, for example if the subject is capable of exhaling through the tubing and inhaling separately from the tubing, the subject S may be allowed to use the apparatus 100 without the breathing adaptor 140. However, if the subject is mentally or physically incompetent, if a medical professional or carer deems it necessary, or if the subject S has a tracheostomy tube forming an artificial airway, a breathing adaptor 720 may be fitted to a distal end of the inlet tubing 123 opposite to the end attached to the container 110. A mouth piece 710 may be provided on the breathing adaptor 720 if the patient is going to be using their mouth to exhale, or alternatively the breathing adaptor 720 may be connected to a corresponding connector of a tracheostomy tube if the subject has an artificial airway provided. [0145] In any case, exhaled fluids from the subject S will be permitted to flow through the fluid conduit 120 into the liquid L in the container 110 to form bubbles B in the liquid L as discussed above, to thereby provide an oscillatory positive expiratory pressure to the airways of the subject S. The exhalation valve 130 is designed to prevent the subject S from inhaling the liquid L if the subject attempts to inhale through the inlet tubing 123, and when a H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 21 breathing adaptor is used the subject S will be able to inhale through the breathing adaptor 140 without needing to inhale separately from the apparatus 100. As the subject S exhales, the exhaled fluids from the subject S are allowed to escape the container 110 via the second opening 232 at the top of the container 110. [0146] By suitable selection of the position, size and shape of the second opening 232, the exhaled fluids can pass freely through the second opening 232 whilst the disturbed liquid L can be retained inside the container 110 by the lid 230. [0147] Following use by the subject S, the breathing adaptor 140 and inlet tubing 123 can be removed from the container 110 and the openings 231, 232 in the lid 230 can be sealed using the attached cap 240, such that the container 110 is closed and can contain the liquid L until the next use of the apparatus 100. In general, the liquid L in the container should be replaced regularly, such as every three days, to ensure hygienic conditions are maintained. As mentioned above, the container 110 may be provided as a disposable product and thus may be disposed of and replaced with a new container 110 if the previous container 110 has become visibly soiled. [0148] In a further detailed clinical usage example, consider the hypothetical case where an elderly patient is admitted to hospital with pneumonia from a high care nursing home with dementia. The patient is productive of thick sputum and has some lower lobe lung collapse, nil by mouth and at risk of aspiration. Oxygen levels are also decreasing secondary to sputum retention. [0149] A physiotherapist may obtain a sterile packaged container 110, and remove it from the sterile packaging, then assemble the apparatus 100 by removing the cap 140 to expose the openings 231, 232 and connecting inlet tubing 123 to the first opening 231. Water would be added through the second opening 232 to provide a predetermined level of pressure (in cm of H20), with reference to measurement markings on the side of the container 110. [0150] Use of the apparatus 100 would follow, with the physiotherapist instructing the subject S to blow through the tubing for approximately 5 seconds and repeating 4-5 times. Bubbles B would be created by the exhaled fluids from the subject creating oscillatory positive expiratory pressure. This would then be followed by the subject S coughing or a H:\ ljr\Interwoven\NRPortbl \DCC\LJR\5017462 1.doc-5/04/2013 - 22 huffing to clear any loosened sputum. After a short break this can be used as an adjunct to other lung clearance techniques or can be repeated. [0151] The use of the apparatus 100 can help to shear secretions off the lung wall, making it easier for the subject S to clear. The resistance to expiration via the apparatus provides end expiratory pressure assisting to decrease atelectasis and lower lobe collapse. Due to the one way exhalation valve 130, the subject S is unable to ingest the water, therefore removing the risk of aspiration to the patient, as well as reducing the chance of the subject being exposed to any contaminants that may be contained in the apparatus 100. The subject S would also be instructed that the water is required to be changed every three days with a date on next change being marked on the lid as a reminder. Additionally, the subject's name is provided on the lid thereby preventing accidental usage by other individuals, which is important in maintaining hygiene. The product would also typically be replaced when visibly soiled. [0152] In any event, in view of the above it will be appreciated that the apparatus 100 provides a convenient means for providing oscillatory positive expiratory pressure therapy to the subject S, and furthermore may significantly reduce the risk of the subject S inhaling liquid L during the course of administration of the therapy. [0153] The practical embodiments discussed above can be constructed using inexpensive manufacturing techniques and may be provided as a disposable product, to thereby eliminate the need to sterilise the apparatus 100 after a period of use. The container 110 may be disposed after a period of use and simply replaced by a new container 110. This allows a low cost solution for providing continuation of care to a subject S without the need for the subject S to obtain an expensive device. Alternatively, the apparatus 100 may be constructed as an assembly of parts which can be easily detached from one another to allow simple cleaning and sterilisation in the event the apparatus 100 is to be reused and not disposed of. [0154] Accordingly, the apparatus 100 provides an improved liquid-based bubble PEP device which helps to mitigate problems associated with improvised bubble PEP devices. [0155] Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be H:\ ljr\Interwoven\NRPortbI\DCC\LJR\5017462 1.doc-5/04/2013 - 23 understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. [0156] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.