Abstract:
The present invention relates to apparatus for treating sleep apnoea. More specifically, the present invention provides a nasal positive airway pressure device which is reliable and comfortable to wear and, consequently, more acceptable to the patient. The nasal device has inflatable cuffs worn in a patient&#39;s nasal cavities. A pair of inflating tubes are in gaseous communication with the interior of a respective one of the inflatable cuffs and when pressurised gases flow through each of the inflating tubes, each of the cuffs inflate to retain the cuff within each of the nasal cavities of the patient.

Description:
BACKGROUND TO THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to apparatus for treating sleep apnoea. More specifically, the present invention provides a nasal positive airway pressure device which is reliable and comfortable to wear and, consequently, more acceptable to the patient.  
           [0003]    2. Summary of the Prior Art  
           [0004]    Obstructive Sleep Apnoea (OSA) is a sleep disorder that affects up to at least 5% of the population in which muscles that normally hold the airway open relax and ultimately collapse, sealing the airway. The sleep pattern of an OSA sufferer is characterised by repeated sequences of snoring, breathing difficulty, lack of breathing, waking with a start and then returning to sleep. Often the sufferer is unaware of this pattern occurring. Sufferers of OSA usually experience daytime drowsiness and irritability due to a lack of good continuous sleep.  
           [0005]    In an effort to treat OSA sufferers, a technique known as Continuous Positive Airway Pressure (CPAP) was devised. A CPAP device consists of a gases supply (or blower) with a conduit connected to supply pressurised gases to a patient, usually through a nasal mask. The pressurised air supplied to the patient effectively assists the muscles to keep the patient&#39;s airway open, eliminating the typical OSA sleep pattern.  
           [0006]    The procedure for administering CPAP treatment has been well documented in both the technical and patent literature. Briefly stated, CPAP treatment acts as a pneumatic splint of the airway by the provision of a positive pressure, usually in the range 4 to 20 cm H 2 O. The air is supplied to the airway by a motor driven blower whose outlet passes via an air delivery hose to a nose (or nose and/or mouth) mask sealingly engaged to a patient&#39;s face by means of a harness or other headgear. An exhaust port is provided in the delivery tube proximate to the mask. More sophisticated forms of positive airway pressure devices, such as bi-level devices and auto-tritating devices, are described in U.S. Pat. No. 5,148,802 of Respironics, Inc. and U.S. Pat. No. 5,245,995 of Rescare Limited, respectively.  
           [0007]    U.S. Pat. No. 5,477,852 of Airways Ltd, Inc. discloses a nasal positive airway pressure device that has a pair of nasal members each having a cannula tip to be inserted into the nares of the patient. Each cannula is tapered from a substantially circular cross-section outside the patient&#39;s nostril to a substantially oval cross-section at the tip inserted into the nostril. An inflatable cuff surrounds each cannula with the interior space of the cuff communicating with the lumen of the cannula through at least one aperture in the sidewall of the cannula. The nasal members are connected to one or more flexible hoses that, in turn, are connected to a source of positive air pressure. In use, positive air pressure is supplied to each cannula tip through the air hoses and nasal members. The positive air pressure inflates the cuffs to hold the nasal members in place and to effect treatment. The nasal device of U.S. Pat. No. 5,477,852 are attached to headgear that is located about a patient&#39;s head. This headgear could be considered by many patient&#39;s as cumbersome and uncomfortable.  
           [0008]    Conventional nasal masks used for administrating CPAP treatment are also considered uncomfortable and cumbersome, also prior art nasal masks and the like are noisy, due to air leaks. These disadvantages in many cases are a formidable obstacle to patient acceptance of such treatment. Therefore, a substantial number of patients either cannot tolerate treatment or choose to forego treatment. It is believed a substantial number of such patients could benefit from a nasal positive airway pressure apparatus that is more convenient to use and comfortable to wear, thereby resulting in increased treatment compliance.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention to attempt to provide a nasal positive pressure device which goes some way to overcoming the abovementioned disadvantages in the prior art or which will at least provide the industry with a useful choice.  
           [0010]    In a first aspect the present invention consists in a device for delivering a supply of gases to a patient comprising or including:  
           [0011]    a pair of nasal members, the distal end of each said nasal member defining a cannula,  
           [0012]    a pair of inflatable cuff members, each said cuff member surrounding at least a portion of each of said cannula,  
           [0013]    a pair of inflating tubes each in gaseous communication with the interior of a respective one of said cuff members, said communication provided through an aperture in each of said cuff member in which a respective one of said inflating tubes extends there through,  
           [0014]    a source of pressurised gases connected to said inflating tubes to deliver pressurized air to the interior of said cuff members,  
           [0015]    wherein, in use, when a respective one of said cuff members is inserted within a respective nasal cavity of said patient and when said pressurised gases flow through each of said inflating tubes, each of said cuff members inflate to retain said cuff members within each of said nasal cavity of said patient.  
           [0016]    To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.  
           [0017]    The invention consists in the foregoing and also envisages constructions of which the following gives examples. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    One preferred form of the present invention will now be described with reference to the accompanying drawings.  
         [0019]    [0019]FIG. 1 is a block diagram of a humidified continuous positive airway pressure system as might be used in conjunction with the present invention,  
         [0020]    [0020]FIG. 2 is a front view of the nasal plugs and associated tubing of one embodiment of the present invention, where the nasal plugs are made from a foam type material,  
         [0021]    [0021]FIG. 3 is a close-up front view of the two nasal plugs of FIG. 2,  
         [0022]    [0022]FIG. 4 is a cross-sectional view of a nasal plug of FIG. 2 through AA as shown in FIG. 3,  
         [0023]    [0023]FIG. 5 is a front view of one of two nasal plugs of a further embodiment of the present invention, where the nasal plugs are made from a silicon type material,  
         [0024]    [0024]FIG. 6 is a cross-sectional view of the nasal plug through BB as shown in FIG. 5,  
         [0025]    [0025]FIG. 7 is a front view of the nasal plugs and associated tubing of yet another embodiment of the present invention, where the nasal plugs are inflatable cuffs,  
         [0026]    [0026]FIG. 8 is a front view of one the inflatable cuffs of FIG. 7,  
         [0027]    [0027]FIG. 9 is a cross-sectional view of the inflatable cuff, through CC as shown in FIG. 8, when the cuff is in the inflated condition,  
         [0028]    [0028]FIG. 10 is a cross-sectional view of the inflatable cuff, through CC as shown in FIG. 8, when the cuff is in the deflated condition,  
         [0029]    [0029]FIG. 11 is a perspective view of the nasal flap, nasal plugs and associated tubing of still a further embodiment of the present invention, where the nasal flap is in the in use, closed position,  
         [0030]    [0030]FIG. 12 is a front view of the nasal flap, nasal plugs and associated tubing of FIG. 11, where the nasal flap is in the in use, closed position,  
         [0031]    [0031]FIG. 13 is a side view of the nasal flap, nasal plugs and associated tubing of FIG. 11, where the nasal flap is in the in use, closed position,  
         [0032]    [0032]FIG. 14 is a perspective view of the nasal flap, nasal plugs and associated tubing of FIG. 11, where the nasal flap is in the open position,  
         [0033]    [0033]FIG. 15 is a front view of the nasal flap and nasal plugs of FIG. 11, where the nasal flap is in the open position,  
         [0034]    [0034]FIG. 16 is a side view of the nasal flap and nasal plugs of the forth form of the present invention, where the nasal flap is in the open position, 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]    It will be appreciated that the improvements to nasal plugs as described in the preferred embodiments of the present invention can be used in respiratory care generally or with a ventilator, but will now be described below with reference to their use in a humidified Continuous Positive Airway Pressure (CPAP) system.  
         [0036]    CPAP System  
         [0037]    With reference to FIG. 1 a CPAP system is shown in which a patient  1  is receiving humidified and pressurised gases through the nasal device  2 , such as nasal cannulae, that are connected to a humidified gases transportation pathway or inspiratory conduit  3 . It should be understood that delivery systems could also be VPAP (Variable Positive Airway Pressure) and BiPAP (Bi-level Positive Airway Pressure) or numerous other forms of respiratory therapy. Inspiratory conduit  3  is connected to the outlet  4  of a humidification chamber  5  that contains a volume of water  6 . Inspiratory conduit  3  may contain heating means or heater wires (not shown) that heat the walls of the conduit to reduce condensation of humidified gases within the conduit. Humidification chamber  6  is preferably formed from a plastics material and may have a highly heat conductive base (for example an aluminium base) which is in direct contact with a heater plate  7  of humidifier  8 . Humidifier  8  is provided with control means or electronic controller  9  which may comprise a microprocessor based controller executing computer software commands stored in associated memory.  
         [0038]    Controller  9  receives input from sources such as user input means or dial  10  through which a user of the device may, for example, set a predetermined required value (preset value) of humidity or temperature of the gases supplied to patient  1 . The controller may also receive input from other sources, for example temperature and/or flow velocity sensors  11  and  12  through connector  13  and heater plate temperature sensor  14 . In response to the user set humidity or temperature value input via dial  10  and the other inputs, controller  9  determines when (or to what level) to energise heater plate  7  to heat the water  6  within humidification chamber S. As the volume of water  6  within humidification chamber S is heated, water vapour begins to fill the volume of the chamber above the water&#39;s surface and is passed out of the humidification chamber  5  outlet  4  with the flow of gases (for example air) provided from a gases supply means or blower  15  which enters the chamber through inlet  16 . Exhaled gases from the patient are exhausted to the ambient surroundings.  
         [0039]    Blower  15  is provided with variable pressure regulating means or variable speed fan  21  that draws air or other gases through blower inlet  17 . The speed of variable speed fan  21  is controlled by electronic controller  18  (or alternatively the function of controller  18  could carried out by controller  9 ) in response to inputs from controller  9  and a user set predetermined required value (preset value) of pressure or fan speed via dial  19 .  
         [0040]    Nasal Plugs  
         [0041]    In a general form, the nasal device  2  generally consists of Y-shaped connector piece that connects the nasal device to the breathing circuit, transportation passageway or conduit  3 , which is connected to the source of pressurised gas. Each arm of the Y-shaped connector is connected to a nasal tube, which are each connected to nasal members. The nasal members have a tapered end terminating in an aperture (cannula), the tapered end has disposed about it nasal plugs. In use, when a patient inserts each of the nasal plugs into their nasal cavities and positive pressure ventilation therapy is commenced, pressurised gases pass through the conduit  3 , into the Y-shaped connector, through each of the nasal tubes exiting into the patient&#39;s nostrils through each nasal cannula, thereby administering positive pressure ventilation therapy to the patient.  
         [0042]    Referring to FIGS.  2  to  4 , there is shown a nasal positive airway pressure device  30  in accordance with a first embodiment of the present invention. Device  30  consists of a Y-shaped connector piece  31  (that is connected to the gases outlet end of the conduit  3 ), and a pair of nasal tubes  32 ,  33  each terminating in a nasal member  34 ,  35 . The Y-shaped connector  31  and each of the nasal members  34 ,  35  are hollow cylinders or tubes that allow for the flow of gases therein. The nasal members terminate in an aperture that is the outlet of pressurised gases from the ventilation system into the patient&#39;s nasal cavities. The end of each nasal member  34 ,  35  defines a cannula, which is basically a tapered end  36  terminating in an aperture. Fitted about each cannula  36  is a nasal plug  37 ,  38  configured and dimensioned to fit within the nasal cavities of a patient. In the first form of the present invention the nasal plugs  37  and  38  are made of a foam type material, preferably a closed-cell foam that has been moulded into the shape of a nostril, that shape being a generally frustoconical.  
         [0043]    The Y-connector  31  and nasal members  34 ,  35  are each moulded from a polycarbonate type material, although other substantially rigid materials may be used, such as rigid plastics or metal. Suitable plastics include homopolymers, copolymers, blends and mixtures of polystyrene, ABS, polycarbonate, acrylics, or polyethylene. Suitable metals include stainless steel, titanium, aluminium and alloys thereof One end of each nasal tube  32 ,  33  is fitted over the arms  39 ,  40  of the Y-connector  31  and the other end of each nasal tube  32 ,  33  is adapted to be connected to each nasal member  34 ,  35 , for example the nasal member may be fitted within the nasal tubes  32 ,  33 . These fittings may be of any convenient manner suitable for coupling without substantial loss of gas pressure, such as by friction fit, snap fit, gluing, welding, threading or the like. The foam nasal plugs  31 ,  38  are fixed about the cannulae  36  by appropriate fixing means, for example by gluing, in a manner that preserves gas pressure.  
         [0044]    The nasal tubing  32 ,  33  are conduits  44  that is, in the preferred form, molded from an elastomeric material such as a Polyethylene/EVA mixture or silicon rubber. The conduit preferably has a “ribbed” “or corrugated” construction to allow bending, (the ribs are referenced as  45 ). This conduit construction may be accomplished by blowing the molten elastomeric material to form an endless cylinder that is forced outwards against the internal surface of a rotating mould that impresses the ribs onto the conduit. The conduit  44  may also have within it a helically wound heater wire (not shown) that preferably sits against or adjacent to the internal wall of the conduit along its length. The purpose of having a conduit with a heater wire is to reduce the condensation of the gases within the conduit. The nasal tubing  32 ,  33  being a “ribbed” conduit provides the advantage of being able to be easily manipulated by the patient for additional patient comfort.  
         [0045]    In use, the patient need only apply pressure to the sides of the foam nasal plugs  37 ,  38  thereby depressing the foam deforming the shape of each of the nasal plugs so that each is easily insertable into each nasal cavity. Once each plug is within each cavity the foam will expand to its original form where the external surface of the foam abuts the internal surface of the patient&#39;s nasal cavity, thereby filling the area within each nostril. The foam nasal plug provides a seal between the cavity and the cannula, effectively eliminating gases leakage, as the expanding foam provides an outward force upon the inner surface of each of the patient&#39;s nasal cavities, which also prevents each plug from falling from the nasal cavity.  
         [0046]    Nasal members  34 ,  35  have disposed in them at least one, but preferably a number of, small holes (not shown) that act as vents to exhaust the gases that are exhaled by the patient. The holes and thus the nasal members may be covered with an appropriate type of material that acts as a diffuser.  
         [0047]    In a further form of the nasal device of the present invention, the nasal plugs may be constructed from a silicon type material. With reference to FIGS. 5 and 6, the, nasal device in this form is almost identical to that as shown in FIG. 2, the difference being the nasal plugs are manufactured from a silicon type material that is formed in an inverted U-shape. The nasal plug and nasal member, as shown in FIG. 6, is a cross-section through BB of FIG. 5. The silicon nasal plug  41  is adapted to be connected to the tapered end  42  of the respective nasal member  40 . This connection may be provided by any appropriate means as discussed earlier in relation to the embodiment of the nasal plugs, but more preferably by a type of glue.  
         [0048]    Again, to allow for exhaust and diffusion of exhaled gases from the patient each of the nasal members (of which only one, labelled  40 , is shown in FIGS. 5 and 6 have disposed in them at least one, but preferably a number of, small holes (not shown) that act as vents to exhaust the gases that are exhaled by the patient into the ambient air. The holes and thus the nasal members may be covered with an appropriate type of material that acts as a diffuser.  
         [0049]    The nasal plug  41  may be made from other appropriately flexible materials that will be deformed under a pressure applied by the user of the nasal device. In use, as a patient inserts the U-shaped plugs into his or her nares the arms of each of the U-shaped plugs are compressed, effectively reducing the space  43  between the tapered end  42  and the interior surface of the nasal plug  41 . Once the plugs are completely inside the nares, the arms of each U-shaped plug expand to their natural position, causing the plugs to be retained within the nares by way of friction.  
         [0050]    In both of the abovementioned forms the nasal plugs provide a good seal within the patient&#39;s nasal cavities, thereby reducing the effects of gases leakage. As the nasal plugs are deformable, they are easily fitted by the patient and provide greater patient comfort when in use. In addition, the forces of the expanding materials, once inserted, hold the nasal plugs within the nasal cavities in a manner that is more comfortable to the patient than prior treatment devices.  
         [0051]    Inflatable Cuffs  
         [0052]    In accordance with a further embodiment of the present invention, FIGS.  7  to  9  show a nasal device  50  that utilises inflatable cuffs  51 ,  52 . The cuffs are attached by appropriate means, for example by moulding or gluing or the like, to the nasal members  53 ,  54 . The nasal members  53 ,  54  are adapted to be connected to nasal tubes  55 ,  56  and the nasal tubes to the Y-connector as described above.  
         [0053]    Each inflatable cuff  51 ,  52  surrounds the tapered end  58  (see FIG. 8) and provides a force, when in use, within the nasal cavity, to hold the tapered end  58  in position within the patient&#39;s nares in a manner to be explained below. Each tapered end  58  of the nasal members  53 ,  54  are preferably substantially oval or elliptical in cross-section at the open end that is distal to nasal members  53 ,  54 , and gradually tapers to a substantially circular cross-section outside the patient&#39;s nares. The inflatable cuffs  51 ,  52  surrounding each tapered end  58  are made of a plastics material, and a small inflation tube  59 ,  60 , made from a flexible plastics material communicates with the interior space of each cuff, preferably through the cuff wall. Both inflation tubes  59 ,  60  are connected to an inflation device, where when the inflation device provides gases to the tubes ( 59 ,  60 ) the cuffs are inflated with the gases. FIG. 9 shows one such inflatable cuff  51  in cross-section when the cuff is inflated in an “in use” form, whereas FIG. 10 shows one such cuff  51 ′ in cross-section when the cuff is the deflated “insertion” form.  
         [0054]    The inflation device that could be used to provide gases to the inflation tubes may be a non-return valve with a fitting at one end, in which a plastic syringe (without the needle) could be placed. The syringe can then be used to force air into each of the cuffs. When the syringe is removed the non-return valve would keep the air in the cuffs. This is similar to the inflation system on an ET tube. To deflate the cuff, the syringe can be inserted into the inflating tubes and valve and draw the gases from the cuff.  
         [0055]    Alternatively, a further inflation device is anticipated which is a small pump mechanism. This would involve having a plastic gases holding compartment with two non-return valves attached on either side of the compartment. One valve would allow air to pass into the compartment from the atmosphere, and once the compartment is compressed, for example, by the patient&#39;s fingers, gases are forced through the second non-return valve, into the inflating tubes, inflating the cuffs. To deflate the cuffs, the pump mechanism would be supplied with a bleed valve, that is preferably hand operated.  
         [0056]    In use, when the patient wishes to commence positive pressure ventilation therapy, he or she must place each cuff within his or her nasal cavities and start the inflation device. As air flows through the inflation tubes  59 ,  60  the cuffs  51 ,  52  will inflate and provide a force against the internal walls of the nasal cavities, preventing the cuffs from falling from the cavities. Again, this embodiment of the nasal plugs of the present invention has the advantage of providing the patient with a comfortable alternative to prior art nasal devices.  
         [0057]    Nasal Snap Flap  
         [0058]    In accordance with a fourth form of the present invention, FIGS.  11  to  16  show a nasal device  60  that utilises an engagement means located about nasal cannulae to engage and secure the cannulae within the nares of a patient. The engagement means is a nasal sealing flap  61 . The flap  61  in its natural bias is tapered, the wide-open end of which is shaped to conform to the facial contours of a patient&#39;s nose around the outside of the nose. Thus in a closed form, as shown in FIGS.  11  to  13 , the flap provides a cup-like device that is fitted around the patient&#39;s nose and prevent the nasal device  60  from falling from the patients nose. In the open form, that allows for placement and fitting of the nasal device  60 , the flap  61  is intended to be in a bent back position, as shown in FIGS.  14  to  16 , to aid insertion of the nasal cannulae  63 ,  64  into the patient&#39;s nares.  
         [0059]    The nasal device comprises the nasal sealing flap  61  connected by appropriate means to a nasal member  62  that terminates in at least one nasal cannula, although in the preferred form two cannulae  63 ,  64  are provided, one for each of the patient&#39;s nares. The flap  61  and cannulae  63 ,  64  may be integrally formed or the flap  61  may be attached about the cannulae  63 ,  64  (by appropriate means, such as gluing) after the cannulae have been formed. Furthermore, the cannulae  63 ,  64 , flap  61  and nasal member  62  may all be integrally formed by injection moulding or the like methods. The cannulae  63 ,  64  extend through the proximate end of the flap  61 , so that in use, upon placing the flap about the patient&#39;s nose the cannulae extend into the nasal cavities of the patient&#39;s nose. The other end of the nasal member  62  is connected, again by appropriate fixing means, such as by friction fit, snap fit, gluing, welding, threading or the like, to a nasal tube  65 .  
         [0060]    The nasal tube  65  is a conduit that is, in the preferred form, moulded from an elastomeric material such as a Polyethylene/EVA mixture or silicon rubber. The conduit preferably has a “ribbed” “or corrugated” construction to allow bending that is constructed as described above with relation to the tubing  32 ,  33  of FIG. 2. The nasal tube  65  is preferably connected to the inspiratory conduit  3  and thus to the rest of the ventilation system as detailed with reference to FIG. 1 above. In an alternative form the nasal tube  65  and conduit  3  may be one tube.  
         [0061]    In use, to attach the nasal device to the nose and nares, the patient bends back the flap  61  to the open position, as shown in FIGS.  14  to  16 , and inserts the nasal cannulae  63 ,  64  into each nostril. To enable the retaining of the cannulae  63 ,  64  within the nares the flap  61  is bent into the closed position, the flap  61  providing a cup-like seal around the patient&#39;s nose. The flap is bent back into the open position to enable removal from the patient, by simply pressing on its outer periphery  66 , until it snaps into the bent back position, in which it will stay unaided. The flap  61  may be adjusted into its operational position by pressing on its outer periphery  66  until it snaps forward to press against the outside of the nose.  
         [0062]    It will be appreciated that as well as providing a substantially airtight seal the flap provides enough compressive force on the nose to keep the nasal device and conduit in place without the need for straps. This allows the administering of positive airway pressure ventilation therapy to be considerably less obtrusive than traditional methods.  
         [0063]    In all forms of the nasal device as discussed above, the friction between the plugs or cuff of the device and the interior surface of the patient&#39;s nares prevents the plugs or cuffs from falling from the patient&#39;s nares. Although it is appreciated that headgear could be used to ensure securement of the nasal device to the patient. Thus, the device may be secured to the head of the user with headgear (not shown) by attaching straps of the headgear at an appropriate point along the length of each nasal tube or at the nasal members. Furthermore, a clip or the like could be used to attach the tubing associated with the nasal device to the patient&#39;s clothes.