US20070089743A1 - Portable continuous positive airway pressure system - Google Patents

Abstract

A portable, wearable vest supports an air supply tube to a patient mask or interface in a continuous positive air pressure system. In one embodiment, the vest contains and supports motor and battery components. In another embodiment, the vest couples a remote CPAP unit to a patient interface.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This application claims the benefit of U.S. Provisional Application No. 60/664,108, filed Mar. 22, 2005, and is a continuation of U.S. patent application Ser. No. 11/128,552, filed May 13, 2005, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
• Continuous positive airway pressure (CPAP) therapy is widely known. This therapy is predominately used to treat obstructive sleep apnea (OSA), as well as other disorders. CPAP therapy is used to deliver pressurized air, to a patient's airway. In general, conventional CPAP systems include a bedside “generator” that operates off either wall current or a large external battery. This generator is a blower or pump that creates a supply of pressurized air. A physician would typically prescribe a maximum CPAP in the range of 5-15 cm of water to treat the disorder. For patient comfort, the generator device may “ramp up” to the prescribed pressure over a period of several minutes.
• The bedside generator is connected to the patient via a long flexible hose that transports the pressurized air from the generator to an interface worn by the patient. The term of art in this industry for the mask-like portion of the system is “interface” and the term is generic for oral, oral-nasal, or nasal designs. There are a wide variety of interfaces that are used and preferred by patients. It is important that the interface fit the patient securely to deliver pressurized air without substantial leakage.
SUMMARY OF THE INVENTION
• The present invention is a portable CPAP unit that integrates a blower unit into a vest worn by the patient. In general the vest is relatively thick and made of foam covered with a cloth material. In one embodiment the vest provides space to house both the air handling system, power supply and control electronics in a balanced arrangement around the neck.
• The vest includes a collar portion that is worn around the neck. The collar portion connects with first and second extended panel portions carried over the shoulder onto the chest of the user. The vest is shaped such that its profile adjacent the patient's neck fits within the contours of the patient's neck and is sized so that it does not protrude beyond planes defined by the patient's body.
• In one preferred embodiment the vest contains a blower unit. The blower unit includes a clamshell housing defining a complex air path for a motor/impeller unit that is also contained within the clamshell housing. The motor/impeller unit and its associated diffuser housing are mechanically isolated from the clamshell housing, and together they form the blower unit.
• A motor control unit and battery pack are placed within the vest to create a self-contained portable wearable CPAP device for treating obstructive sleep apnea (OSA) and other disorders.
• In an alternate embodiment the vest itself is coupled to the remote air pressure generator and it serves to transfer air from the generator to the interface. In this embodiment the vest serves to decouple the user and most importantly the nasal interface from the remote generator. It has been found that decoupling the mask improves acceptance of the therapy and in this embodiment the vest allows air to pass through the vest from the generator to the interface.
BRIEF DESCRIPTION OF THE DRAWINGS
• Throughout several figures identical reference numerals refer to identical structure wherein:
• FIG. 1 is a schematic top view of a patient, lying down, wearing the wearable CPAP unit;
• FIG. 2 is a schematic side view of a patient wearing the portable CPAP unit;
• FIG. 3 is an isometric view showing the orientation, relationship and position of various elements of the wearable CPAP unit;
• FIG. 4 is an isometric view of the impeller diffuser inlet and outlet portion of the device;
• FIG. 5 is a schematic top view of an alternate embodiment;
• FIG. 6 is a view of an interface particularly suited for use in the system; and
• FIG. 7 is an enlarged perspective view of one of the cannulas of the interface ofFIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• FIG. 1 shows the general configuration of a portable self-containedwearable CPAP vest14 being worn by a patient oruser10 who is depicted in a supine position on abed11 with apillow16 under his head.
• Thevest14 has a rounded neck portion orcollar30 positioned at the nape of the neck of the user. Thecollar30 connects with and flares out onto afirst panel26 and asecond panel28 that lie over the chest of theuser10. Eachpanel26,28 has alower edge29,31, respectively, and aninner edge33,35, respectively. The optimal size and shape of thecollar30 and thepanels26 and28 will depend upon the stature of theuser10. In general, it is desirable that the cross-section of thecollar30 proximate the neck of the user be of reduced cross-section or diameter, and have a contoured shape such that it fits within the nape of the neck and does not act as a “pillow” or interfere with the patient'sactual pillow16 when thepatient10 reclines. This relationship is depicted inFIG. 2 which shows asupine patient10 and an associatedplane32 defined by and extending from the back of the head to the shoulder blades. It is preferred to have thecollar30 not completely fill the nape of the neck so that thecollar30 does not touch or extend beyond theplane32 toward thebed11.
• Returning toFIG. 1, it is also preferred to have the exterior edges of thepanel portions26 and28 lie within the shoulder-width of the patient and within the head-to-shoulder plane identified byreference numeral34 inFIG. 1. It has been found that when these several conditions are met thepatient10 may rest on his side and roll over in his sleep with the head and shoulders in a natural posture. When appropriately sized, thecollar30 andpanels26,28 do not interfere with the comfort of the patient. These geometric and dimensional attributes define the shape of avest14 that may be worn unobtrusively during sleep. It has been found that these design attributes associated with these cross-sectional areas and bulk of the panels are designed not to interfere with patient comfort.
• Also shown inFIG. 1, theconnection hose22 couples thevest14 to a user interface ormask24. Themask24 serves as an air delivery device and other interfaces may be readily substituted within the context of the invention. The proximal end of thehose22 couples to onepanel portion26 of thevest14 at anoutlet20. In operation, air entering the vest viainlet18 is pressurized within thevest14 and transferred to thehose22 and thence to themask24 or other interface structure.
• The distal ends of thepanels26 and28 may be connected together by aclasp27 or other device to keep the vest oriented on the patient. In a similar fashion the panels may be fixed to the clothing of theuser10 by structures (not shown) to maintain orientation of thepanels26,28 with respect to the chest of the user.
• FIG. 3 shows ablower unit housing40 inpanel26 of thevest14. Thisblower unit housing40 contains within it, a motor/impeller and associateddiffuser scroll unit42. Many mechanical features and structures and relationships further described, have been found to be effective in suppressing noise generated by the pressurization of air within thevest14. These features are described in connection withFIG. 4. In general theblower unit housing40 and motor/impeller unit have together several attributes that will, in combination, produce a very quiet blower that is believed to be an important characteristic for acceptance of the vest by the user. It is advantageous for the motor impeller unit to use very low power to allow portable battery operation and to prevent excessive heat build up in the device or in air exiting the device.
• Thesecond panel28 of thevest14 contains abattery pack36 coupled to an electronicmotor control unit38. Thebattery pack36 being compact in nature and has sufficient capacity to operate thevest14 for periods of time approximating ten hours or so. Buttons (not shown) on thecontrol unit38 are exteriorized for use by thepatient10. Thecontrol unit38 carries motor control functions (e.g. an on/off switch) and a charging receptacle or jack to permit the patient10 to recharge thebattery pack36.
• The partitioning of thebattery pack36,control unit38 andblower unit housing40 is intended to equalize the weight of theside panels26 and28 to make them roughly equivalent, which helps maintain thevest14 in position on the wearer oruser10. To achieve this result, it is permissible to reorganize the distribution of weight throughout the vest and it is anticipated that the battery pack may be split or placed elsewhere in thevest10. Electrical connections, not shown to simplify the figure, are buried within the foam of thevest10 and connect thecontrol unit38 with thebattery pack36 and the motor within theblower unit housing40.
• It is preferred, but not essential, that themotor blower unit40 exhaust its output to a location near the center line of thepatient10. Ashort hose22 couples theoutlet20 to a user interface or distribution device, such as a mask24 (shown inFIG. 1) or nasal cannula (not shown) to provide CPAP flow to the patient's airways. Ashort light hose22 produces less pull on themask24 or interface worn by the patient promoting less movement of the mask on the patient face with subsequently a better seal. Also, not being connected to a bed-side CPAP unit provides freedom of movement for the patient.
• It is also preferred, but not essential, to have theair inlet18 for theblower unit housing40 near the bottom of one side, or adjacent one panel, of thevest14 as seen with reference toinlet18 onFIG. 1 andFIG. 2. This location directs noise away from patient and bed partner and is generally unobstructed during sleep for most patients. Other alternative locations are contemplated including connections on the upper surface of the collar or panel away from the patient.
• It is the applicants' view that acceptance of a portable CPAP unit depends in large measure upon suppressing to the extent possible noise created by the motor blower unit. The existence of a loud motor next to the patient would be disconcerting and uncomfortable, and thereby may reduce usage, so every effort is made and a substantial effort is directed to designing the motor to suppress sound described in connection withFIG. 4.
• InFIG. 4, theblower unit housing40 is shown with a cross-section taken at line4-4 inFIG. 3. This figure depicts the motor/impeller and associatedscroll housing42 contained within theblower housing40. Theclamshell housing40 defines a labyrinthine air path between aninlet18 to the motor/impellerunit inlet annulus54. The motor/impeller andscroll unit42 accelerate the airflow and increase the kinetic energy in the airflow. The diffuser scroll is formed integrally with the motor and it serves to convert the kinetic energy to a static pressure delivered to theoutlet20 that is also the end of the “scroll” passage shown as theshort tube21.
• DC brushless motor elements are adjacent to theimpeller wheel55. Theimpeller wheel55 is supported cantilever fashion on an axle by twobearings53 and57, each of which is below theimpeller55. The motor elements,impeller55, anddiffuser scroll42 form an independent mechanical unit that is isolated from theblower housing40. It may be suspended by or mounted on a foam pad or a set of rubber standoffs (not shown). Thus, the motor/impeller elements lie within a “cocoon” likechamber58 and are mechanically isolated from the remainder of theblower unit40.
• Returning to theblower housing40 the preferred construction is a clamshell with a top44 or lid fitting on top of a lower46 clamshell portion. The housing is lined with a foam and it has a complex passage diverting air flowing alongpath60 through two ninety degree turns depicted in the figure byflow arrows62 and64 to turn the airflow through a tortuous path to theinlet annulus54 of theimpeller55. As the airflow approaches theannulus54 it passes over a firstannular baffle48 and then a secondannular baffle50. These baffles help suppress the radiation or conduction of noise emanating from the motor/impeller.
• In the preferred embodiment ofFIG. 1, thevest14, as described above, houses and supports operational components such as theblower unit housing40 with motor impeller andscroll unit42, thebattery pack36 and thecontrol unit38. In addition, thevest14 supports thehose22 that carries air from the operational components to theuser interface24. One of the advantages achieved by this arrangement over the conventional bedside CPAP machine is that forces that tend to pull a mask away from a patient's nose and mouth are significantly reduced. Thus, the “head gear” required to hold the interface to the patient's face need not be elaborate. The embodiment ofFIG. 1 lacks the conventional straps used to secure the interface to the face. The vest is very stable in position on the patient and most patient motion does not result in significant forces applied to the mask or interface. If thecompliant tube22 is biased toward the face, then a force is generated to retain the interface on the face.
• FIG. 5 depicts an alternative embodiment where auser interface105 connects via avest114 to a traditionalbedside CPAP unit115. Thevest114 supports ahose section120 between thevest114 and theCPAP unit115. In addition, thevest114 supports ahose section125 between thevest114 and theuser interface105.Hose sections120 and125 are in fluid communication, and may be continuous or may be in discrete sections, to allow air from the CPAP unit to pass to theuser interface105. The vest may include aconduit126 passing from theinside edge130 of onepanel131 to theoutside edge132 of thepanel131, withhose section125 connected to the inside edge andhose section120 connected to the outside edge.
• Thevest114 bears and disperses to the patient's torso the mechanical forces transmitted by thehose section120, so that those forces are not transmitted to thehose section125. In this manner, theuser interface105 is de-coupled from these forces and therefore the interface is held in place without significant head gear. TheFIG. 5 embodiment provides no straps to hold the mask in place. Thevest114 may include operational components, as described above with respect to theFIG. 1 embodiment, and allow the user to selectively couple thehose section125 to the outlet of the in-vest blower or to the outlet of a conventional bedside CPAP unit, as desired.
• FIG. 6 shows a nasal mask orinterface200 that uses only very “light” retention straps210 to keep theinterface200 on the face of the user. Themask200 includes twonasal cannulas220,221 which, in use, are inserted into the patient's nostrils. These cannulas orportals220,221 are designed to experience minimal lateral movement and are stabilized by themask200 fitted over the patient's nose. Themask200 is sized to cover the patient's nose, but not the mouth.FIG. 7 illustrates one of thecannulas220.

Claims (1)

1. A portable wearable continuous positive air-pressure system of the type used for the treatment of obstructive sleep apnea and other disorders by a patient comprising:

a blower unit housing having an air inlet and having an outlet to provide output air at a pressure of between 5 and 15 cm water;

brushless DC motor elements coupled to an impeller wheel located within said blower unit housing supplying air to an outlet from an inlet;

said brushless DC motor elements coupled to a motor control unit;

a battery pack coupled to the control unit, the control unit having motor control functions; and

a compliant hose coupled to an interface positioned on the face of the patient, said hose coupled to said outlet, whereby air is transferred from said blower to the patient;

said blower unit, motor and battery pack being disposed within a wearable vest.

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