Abstract:
A nasally introduced catheter (nasal catheter) has a portion in which a user&#39;s breath (breathing air) air travels internally and a portion in which the breath travels externally. The portion in which air flow travels internally preferably includes a mesh or a whisk-like portion that expands and contracts, and the portion in which air flow travels externally preferably comprises a proximal tubular element having a sufficiently small cross-sectional area that at least 50% of the breathing air flows externally to the proximal portion. A sheath can optionally be positioned about the distal portion, and pulled back along the proximal portion to allow the distal portion to expand. In other aspects users can anchor the proximal and distal portions relative to the sheath using a nose clip or by removably coupling an extension arm to proximal portion

Description:
[0001]    This application claims the benefit of U.S. provisional application No. 60/823910 filed on Aug. 30, 2006 incorporated herein by reference in its entirety. 
     
     FIELD OF THE INVENTION  
       [0002]    The field of the invention is nasal catheters (class 128/207.18). 
       BACKGROUND  
       [0003]    There are several diseases, conditions, and situations in which it is desirable to artificially maintain patency of the nasal passageway and pharynx. 
         [0004]    The simplest solution is to insert a tube of sufficient length and internal diameter through a nostril and into to the nasal passageway. The lumen of the tube then provides the airway. With minor modifications, that approach was adopted in Dunlap 2006/0048775 (March 2006). Dunlap and all other referenced extrinsic materials are incorporated herein by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. 
         [0005]    The main problem with the Dunlap approach is that the inner diameter of the tube must be at least 5 mm, and more preferably at least 10 mm. Such tubes are very uncomfortable for the users. An alternative approach is typified by Dubrul 2004/0020492 (February 2004) in which a wire mesh is inserted in a compressed configuration, and then expanded along its entire length. Dubrul&#39;s approach might be somewhat better tolerated than Dunlap because the walls comprise a mesh as opposed to a solid barrier. But Dubrul still contemplates a filly deployed catheter that comprises a large tube over substantially the entire length of the device inside the user. 
         [0006]    There is another, very serious problem with Dubrul, namely lack of enablement as to how the sheath  4  is to be slid relative the mesh (support element)  6  and the proximal end  10 . There is no disclosure at all as to what the user can hold onto while pulling or pushing on the sheath  4 . When fully inserted, the only portion that could be held by the user is proximal end  10 , and that proximal end  10  would be inside the sheath  4  during at least some portion of the sheath travel. 
         [0007]    Thus, there is still a need for a practical nasal catheter, one that has an expandable portion and a more tolerable cross-section for a portion that is either not expandable or at least less expandable. 
       SUMMARY OF THE INVENTION  
       [0008]    The present invention provides apparatus, systems and methods in which a nasally introduced catheter (nasal catheter) has a portion in which a user&#39;s breath (breathing air) air travels internally and a portion in which the breath travels externally. 
         [0009]    In preferred embodiments, the portion in which airflow travels internally comprises a distal portion of the device, and can for example, include a mesh or a whisk-like portion that expands and contracts. Also in preferred embodiments, the portion in which air flow travels externally comprises a proximal tubular element having a sufficiently small cross-sectional area that at least 50% of the breathing air flows externally to the proximal portion. 
         [0010]    The distal, expandable portion preferably has a length of between 5 cm and 13 cm when in an expanded configuration, and between about 10 cm and 16 cm in a contracted or other non-expanded configuration. In typical contemplated configurations, the fully expanded configuration is no more than 30% shorter than the fully contracted configuration. Viewed from another perspective, the distal, expandable portion preferably has a maximum cross-section of no more than 18 mm 2  when in a non-expanded configuration and a maximum cross-section of no less than 50 mm 2  when in the expanded configuration. 
         [0011]    The proximal portion can comprise a single wire, braided or twisted wires, or even an inner member that is co-axial and slidable within an outer member. In that later embodiment, the inner member preferably extends to a nub or other functionally distal end of the distal portion. Pulling the inner member proximally pulls on the nub, and thereby bends wires in the distal portion from a substantially parallel configuration to a substantially whisk-like bulbous configuration. 
         [0012]    Nose clips or other stops are also contemplated. Preferred stops extend from the proximal portion and bend around one of the user&#39;s nostrils, at least sufficiently to prevent the end of the proximal portion from entering the nostril. In some contemplated variations, a nose clip is functionally coupled to the distal end of the distal portion, such that operation of the nose clip expands or reverses expansion of the distal portion, 
         [0013]    In some embodiments a sheath can be positioned about the distal portion, and pulled back along the proximal portion to allow the distal portion to expand. Pushing the sheath back over the distal portion causes reversal of the expansion. It is contemplated that users can anchor the proximal and distal portions relative to the sheath in any suitable manner, including: (1) using the nose clip as the anchor, and running the sheath along the outside of the proximal portion via a slit along the side of the sheath; and alternatively (2) removably coupling a extension aim to proximal portion, and using the extension arm as the anchor. 
         [0014]    Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. 
     
     
       BRIEF DESCRIPTION OF THE DRAWING  
         [0015]      FIG. 1  is a perspective side view of a preferred embodiment. 
           [0016]      FIG. 2  is a perspective side view of an alternative embodiment in which the proximal portion has an inner member slidable against an outer member. 
           [0017]      FIG. 3  is a perspective side view of an alternative preferred embodiment having a removable extension arm. 
           [0018]      FIG. 4A  is a perspective side view of a preferred embodiment in which the wires of the distal portion are parallel. 
           [0019]      FIG. 4B  is a perspective side view of the embodiment of  FIG. 4A , where wires of the distal portion are distorted into a whisk-type configuration. 
           [0020]      FIG. 5A-5C  are a perspective side views of a distal portion of the embodiment of  FIGS. 4A and 4B , in varying stages of deployment. 
       
    
    
     DETAILED DESCRIPTION  
       [0021]    In  FIG. 1  a nasal catheter  100  generally includes a proximal portion  110 , a distal portion  120  with a nub  122  at the end, a removable sheath  130 , and a nose clip  140 . 
         [0022]    The proximal portion  110  is a wire of satisfactory length, which is currently contemplated to include lengths sufficient to reach from the external nares to the posterior choanae. Currently preferred lengths are 5-10 cm, with this and all ranges being inclusive of their endpoints unless the context clearly dictates the contrary. Wire  110  can be made of any suitable material or materials, provided they are sufficiently flexible to be inserted in the nasal passageway of a typical human without causing substantial damage to the tissues, but also having sufficient column strength to enable proper insertion of the distal portion. The wire  110  should also be non-kinkable under ordinary operating conditions. Wires  110  can be mono- or poly-filamentous, and in the later case can be twisted, wound, or woven. At present, the most preferred wires  110  are wound, comprise a nitinol or other shape-memory metal or alloy, and have an outside diameter of less than 6 Fr. (2 mm), and are coated with a terephthalate or other suitable bio-compatible polymer to reduce friction. 
         [0023]    The distal portion  120  can have any suitable dimensions, including for example a length of between 7 cm and 13 cm when in an expanded configuration, and more preferably between about 9 and 11 cm. Preferred distal portions also have a maximum cross-section of no more than 10 mm 2  when in the non-expanded configuration, and no less than 75 mm 2  when in the expanded configuration. Both length and diameter dimensions are derived from typical adult anatomy, and other sizes are also contemplated, such as to accommodate children and very large adults. 
         [0024]    Distal portion  120  can advantageously comprise the same material(s) and coating(s) as the proximal portion, but could be also be quite different. Where the distal portion comprises a mesh, it is important that the mesh defines spacing sufficient to accommodate both expected airflow and ordinary fluid drainage. In a currently preferred embodiment the spacing is approximately a square measuring about 2 mm on a side in the expanded configuration. In the expanded state the mesh would need to have sufficient radial force to part the pharyngeal tissue and provide a patent physiologic airway. But at the same time the radial force should advantageously be less than the tissue perfusion pressure to ensure adequate tissue oxygenation. 
         [0025]    It is important that the distal portion  120  is biased to the expanded configuration, but that the expansion can be manually reversed to a compressed configuration by sliding the sheath  130  over the expanded distal portion with a reasonable amount of effort. The distal portion  120  has a length in an expanded configuration that is at least 50% less than in a contracted configuration, more preferably at least 20% and most preferably at least 25%. 
         [0026]    Nub  122  is optional. One could alternatively leave the distal portion open at its distal end. In that case the end is preferably woven back or otherwise adapted to reduce injury to adjacent tissues. Where nub  122  is present, it is preferably made of a plastic or other relatively soft material, and is preferably bull-nosed to allow for convenient insertion. 
         [0027]    It is also considered advantageous that the nub can be withdrawn into the mesh so that it does not irritate or tickle the vocal chords. This could be accomplished by inherent design of the mesh, so that when the mesh is expanded the nub is automatically pulled back. In the embodiment of  FIG. 2 , a nasal catheter  200  generally includes a proximal portion  210 , a distal portion  220  with a nub  222  at the end, a removable sheath  230 . But in this case the proximal portion  210  has an outer member having a lumen through which an inner member  215  slides. Inner member  215  is coupled to nub  222 , and can be used to invaginate nub  222  back into the lumen of the mesh of distal portion  220 . In this instance nub  222  should be considered a functionally distal end of the distal portion  220 . 
         [0028]    Removable sheath  130 ,  230  is preferably similar to cardiovascular guide catheter in that it needs both considerable column strength and lateral bending flexibility, with a relatively thin wall. This can readily be accomplished using a plastic embedded with metal strands. At its distal end, the sheath  130 ,  230  is preferably tapered to fit flush with the proximal end of the nub  122 ,  222 . This expected to facilitate atraumatic insertion. Sheaths  130 ,  230  can be any convenient length, because it will likely not be left in the body. 
         [0029]    Sheaths  130 ,  230  can be split, so that they can be placed over the protrusion of the proximal portion out of the nose, which is likely continuous with the nose clip  140 . See  FIG. 1 . At the proximal end of the sheath  130 ,  230 , one could have a handle, grip or other protuberance that facilitates gripping and manipulating of the sheath  130 ,  230  by the user or his health care provider. 
         [0030]    In an alternative shown in  FIG. 3 , a nasal catheter  300  generally includes a proximal portion  310 , a distal portion  320  with a nub  322  at the end, a removable sheath  330 , and a nose clip  340 . Here, however, the nose clip  340  is removably attached to the proximal portion  310  (such as for example with a snap or a threaded connection) and there is an extension arm  350  that is removably coupled to the proximal portion  310 . In practice one would insert the catheter  300  by sliding the sheath  330  over the distal portion  320 , inserting the catheter  300  into the nose of a user (not shown) an appropriate distance connect the extension arm  350  to the proximal end of the proximal portion  310 , withdrawing the sheath  330  over the proximal portion  310  and then over the extension arm  350 , detach the extension arm  350  from the proximal portion  310 , and finally attach the nose clip  340  to the proximal portion  310 . When removing the catheter  300 , one reverses the steps above. Extension arm  350  can, of course, be made of any suitable materials and have any suitable length. 
         [0031]    Nose clip  140 ,  340 ,  440  primarily functions to prevent the proximal portion  110 ,  210 ,  310  from sliding further than intended into the nasal cavity, and in extreme situations, advancing to a point that it cannot be easily retrieved. In that light the term nose clip should be construed euphemistically as including any sort of position retaining device that can prevent such untoward events. Thus, for example, a nose clip can be a simple bent wire  140  such as that shown in  FIG. 1 , or a combination plastic and metal piece such as that shown in  FIG. 3 . In still further alternative embodiments (not shown), the retaining device could be a flared segment, a band that can be positioned about the head, and so forth. 
         [0032]    Another purpose for the nose clip is to act as a positioning guide, indicating that the device is appropriately inserted. The nose clip can also be rotated clock-wise or counter-clockwise by a few degrees, which would also tend to rotate the entire length of the device, and thereby reducing potential for repetitive contact injury and areas of ischemic tissue damage. Users should in fact be encouraged to rotate the nose clip by a few degrees each day. 
         [0033]    In  FIGS. 4A and 4B , a nasal catheter  400  generally includes a proximal portion  410 , a distal portion  420  with a collection of wires  420 A,  42013  terminating at a nub  422 , a sheath  430 , and a nose clip  440 . 
         [0034]    One of the wires  420 A is slidable with respect to the sheath  430 , and the other wires  420 B are not slidable with respected to the sheath. In that arrangement, the distal and proximal portions  410 ,  420  can be inserted through the nose, with the distal portion  420  being in a contracted configuration. Retracting the slidable wire actuates the device by distorting the orientation of the remaining wires  420 B to form a whisk-shaped distribution shown in  FIG. 4B . The motion is similar to that found in the guidewire system of Cordis™ Angioguard XP™, except that in the Cordis device the guidewires go flush by pulling the ends apart, and in the embodiments of  FIGS. 4A ,  4 B, the wires expand to the whisk-shaped distribution by bringing the ends towards one another (i.e. bringing the nub  422  proximal). 
         [0035]    Catheter  400  preferably has between  8 - 20  wires  420 B. It is currently contemplated that operation at the lower end of the range and below would tend to allow excessive tissue prolapse between the wires, and operation at the higher end of that range and above would tend to have inadequate radial separation and cause inspisated mucus buildup. 
         [0036]    The wires  420 B can extend proximally any suitable distance. They could, for example, terminate at or approximately at the distal end  432  of the sheath  430  (as shown in the figures), pass all the way to the proximal end of the sheath  430 , or terminate anywhere in between. 
         [0037]    It should also be appreciated that wires  420 B need not have a round cross-section. They could, for example, be flattened into ribbons, or have ovoid cross-sections. 
         [0038]    In  FIGS. 5A ,  5 B,  5 C the nub  422  is coupled to the wires  420 B at pivot points  423 . This is intended to reduce breakage of the wires  420 B and increase the lifespan of the device  400 . The nub  422  also preferably includes grooves  424  that allow the wires to become flush with the surface of the nub  422 , which is expected to facilitate insertion. Those of ordinary skill in the art will appreciate that the  FIGS. 5A ,  5 B,  5 C only depict two wires  420 B for the sake of clarity. A practical embodiment would likely have eight or more. 
         [0039]    Thus, specific embodiments and applications of nasal catheters have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.