in fig1 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 . 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 . 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 . 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 . 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 %. 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 . 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 fig2 , 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 . 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 . 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 fig1 . 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 . in an alternative shown in fig3 , 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 . 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 fig1 , or a combination plastic and metal piece such as that shown in fig3 . 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 . 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 . in fig4 a and 4b , a nasal catheter 400 generally includes a proximal portion 410 , a distal portion 420 with a collection of wires 420 a , 420 b terminating at a nub 422 , a sheath 430 , and a nose clip 440 . 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 fig4 b . 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 fig4 a , 4 b , the wires expand to the whisk - shaped distribution by bringing the ends towards one another ( i . e . bringing the nub 422 proximal ). 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 . 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 . 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 . in fig5 a , 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 fig5 a , 5 b , 5 c only depict two wires 420 b for the sake of clarity . a practical embodiment would likely have eight or more . 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 .
a nasally introduced catheter has a portion in which a user &# 39 ; s breath 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 .