# Patent

## Title
Ventilator to tracheotomy tube coupling

## Abstract

A coupling for connecting a ventilator tube to a tracheotomy tube has a latching mechanism which prevents the coupling from axially displacing a tapered tubular extension of the tracheotomy tube after they have been mated in a pneumatically discrete path. For use with known adult tracheotomy tubes which have inner and outer cannulas, the latching mechanism engages the coupling with the leading end of the outer cannula collar with the inner cannula collar sandwiched therebetween. For use with known one piece children's tracheotomy tubes, the latching mechanism is a clamshell contoured to concentrically grip the tapered tubular extension of the tracheotomy tube. Interlocking the coupling and the tracheotomy tube prevents them from inadvertently axially displacing from each other. Non-axial force disengages the coupling from the tracheotomy tube so that the coupling can be axially displaced without exertion of excessive axial force on the system and the patient.

## Background
BACKGROUND OF THE INVENTION
This invention relates generally to medical equipment and more particularly concerns devices used to connect ventilators to tracheotomy tubes.
For adult patients, two-piece tracheotomy tubes having inner and outer cannulas are presently in common use. The outer cannula is inserted into the patient's windpipe and the inner cannula is inserted into or removed from the outer cannula for use or for replacement, cleaning or disinfecting, respectively. The outer cannula of these two-piece devices has a collar on its trailing end which is configured to be positively engaged with a collar on the leading end of the inner cannula. The cannulas cannot be disengaged from each other affirmative release of their positive engagement. The trailing end of the combined cannulas has a tapered tubular extension which plugs into or into which is plugged, depending on the diameter of the tubular extension of the particular tracheotomy tube, the leading end of a flexible connector. The trailing end of the flexible connector is connected to a tube extending from the ventilator or other external equipment. The present tapered tubular extension connection to the ventilator is dependent on mere insertion of a tapered tube into a constant diameter tube in the hope of achieving a snug fit. To assist in making this connection, the flexible connectors have annular flanges with significantly wider diameters than the tubular portions of the connectors so as to facilitate manipulation of the connectors with the thumb and forefinger.
For children, a smaller, one piece tracheotomy tube is made from a very soft, pliant material. The entire tracheotomy tube must be frequently removed, at least once a week, from the child's trachea, cleaned and disinfected and reinserted into the trachea. The same flanged flexible connector used with the adult devices is also used with the children's devices. The tapered tubular extension of the children's tracheotomy tube is integral with the pliant tracheotomy tube and has a hard plastic outer sleeve which is inserted directly into the flexible connector. An annular flange on the trailing end of the tubular extension of the child's tracheotomy tube holds the hard plastic sleeve in place on the extension.
Because of their structural configuration and operational steps, there are some problems inherent in the known one or two piece tracheotomy tubes, in the known flexible connectors and in their combination.
One set of problems is related to the comfort of the patient. The profile of the flanged flexible connectors, falling generally between the underside of the patient's chin and the patient's chest, fosters a breakdown of skin and tissue on the chin or chest, depending on the head movements of the patient. This is especially true for children, their chin-to-chest cavity being comparatively small. This concern is sometimes addressed by after-market removal of all or a portion of the flange, but this solution generally results in a damaged connector, increasing the likelihood of infection-causing secretions and also becomes less secure due to removal of the firm portion of the connector. Also, the manipulation of the flange to connect or disconnect the connector to or from the tubular extension can cause considerable discomfort to the patient, since this often requires the application of manual pressure to the patient's neck, chin or chest. It is common practice to extend rubber bands from one side of a neck plate on the tracheotomy tube collar to the flexible connector and back to the other side of the neck plate in an effort to hold the flexible connector in place, but the rubber bands are likely either too elastic or too inelastic to properly accomplish this purpose. While a child's tracheotomy tube is smaller than an adult's, the available space between the chin and chest is significantly smaller and the flexible connector flange is the same size as used for adults, so the smaller device affords no relief for the connector flange related comfort problems. And, since the child's tracheotomy tubes are of one piece construction, the force necessary to disconnect the flexible connector may be directly applied to the patient's neck or windpipe.
A second set of problems is related directly to the ability, or inability, of the system to accomplish its primary purpose of keeping the patient's trachea connected to the ventilator. To begin with, tapered connections tend to easily separate in the best of circumstances, there being minimal surface contact between the tapered and constant diameter components. Moreover, the connector and tracheotomy tube parts are always wet and slippery due to the very nature of their application and are not very tightly mated because of the neck pressure problems. The end result is a connection so tenuous that a mere sneeze, cough or turn or tip of the head can cause the connector and the tapered tubular extension to separate, defeating the operation of the system. Even without a sneeze, cough, turn or tip, the flange itself functions as a lever against the chin or chest in response to the patient's head movements, and the reciprocal levering by the flange will eventually cause the connector and the tubular extension to disconnect.
A third set of problems concerns the performance of the medical staff as a result of these other problems. The inherent comfort issues result in more pains-taking, time-consuming effort by the staff in an effort to reduce the impact of these discomforts on the patient. And, because of the ease of inadvertent disconnection of the system, the staff unnecessarily spends valuable time monitoring and reconnecting the connectors to the tubular extensions of the tracheotomy tubes.
It is, therefore, a primary object of this invention to provide an improved tracheotomy tube coupling. Another object of this invention is to provide a tracheotomy tube coupling which reduces a likelihood of associated patient discomfort. It is also an object of this invention to provide a tracheotomy tube coupling which is more suitably profiled for positioning between a patient's chin and chest. Still another object of this invention is to provide a tracheotomy tube coupling which is profiled to reduce a likelihood of skin or tissue breakdown on a patient's chin and chest. A further object of this invention is to provide a tracheotomy tube coupling which simplifies manipulation of the coupling in relation to the patient. Yet another object of this invention to provide a tracheotomy tube coupling which reduces a likelihood of exertion of discomforting pressure on the chin, neck, chest or windpipe of a patient during connection or disconnection of the coupling from the tracheotomy tube. An additional object of this invention is to provide a tracheotomy tube coupling which makes inadvertent disconnection of the tracheotomy tube from the connected medical equipment less likely. Another object of this invention is to provide a tracheotomy tube coupling which does not rely on tapered to constant diameter connections to maintain connection between the tracheotomy tube and its related equipment. It is also an object of this invention to provide a tracheotomy tube coupling which is profiled to reduce a likelihood that the coupling will operate as a self-disconnecting lever. Still another object of this invention to provide a tracheotomy tube coupling which can be easily connected and disconnected from the tracheotomy tube by the medical staff. A further object of this invention is to provide a tracheotomy tube coupling which can reduce the time expended by the medical staff to monitor and maintain the coupling connections. Yet another object of this invention is to provide a tracheotomy tube coupling which facilitates more rapid disassembly and reassembly of associated components from the tracheotomy tube for cleaning and disinfecting purposes.
SUMMARY OF THE INVENTION
In accordance with the invention, a coupling is provided for connecting a ventilator tube to a tracheotomy tube. The ventilator tube has a connector at its leading end and the tracheotomy tube has a tapered tubular extension on its trailing end. The coupling is a preferably expandable, flexible tubular member with a first adapter on its trailing end for connecting its trailing end in a pneumatic flow path to the ventilator tube leading end connector and a second adapter on its leading end for mating its leading end in a pneumatic flow path with the trailing end of the tracheotomy tube. The second adapter has a latching mechanism for engaging the leading end of the coupling to the tracheotomy tube to prevent the leading end of the tubular member from axially displacing from the trailing end of the tracheotomy tube after they have been mated in the pneumatic flow path. An unlatching mechanism is provided for disengaging the latching mechanism from the tracheotomy tube so as to permit the leading end of the tubular member to axially displace from the trailing end of the tracheotomy tube. The unlatching mechanism is operated by non-axial forces so that the coupling can be disengaged from the tracheotomy tube without exertion of excessive axial force on the patient's neck.
Some known adult tracheotomy tubes have an inner cannula inserted into a trailing end of an outer cannula with the tubular extension on the trailing end of the inner cannula. For such tracheotomy tubes, the coupling tubular member has a first means on its leading end for mating the tubular member in the pneumatic flow path with the tubular extension of the inner cannula which is operable by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the outer cannula during mating to prevent the leading end of the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the inner cannula for disengaging the engaging means from the outer cannula by application of force to the mating means in other than the generally axial direction to permit the leading end of the tubular member to axially displace from the tubular extension of the inner cannula. Typically, the trailing end of the outer cannula has opposed annular flanges and the engaging means consists of opposed means for resiliently snapping over the flanges. The disengaging means consists of means on the inner cannula for spreading the opposed flanges during rotational motion of the mating means about a longitudinal axis of the tubular member.
Other known adult tracheotomy tubes have an inner canula inserted into a trailing end of an outer cannula with the tubular extension on the trailing end of the inner cannula. For such tracheotomy tubes, the coupling tubular member has a first means on a leading end of the tubular member for mating the tubular member in the pneumatic flow path with the tubular extension of the outer cannula by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the outer cannula during mating to prevent the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the outer cannula which is operable by application of force on the mating means in a direction other than the generally axial direction for disengaging the engaging means from the outer cannula to permit the tubular member to axially displace from the tubular extension of the outer cannula. Typically, the trailing end of the outer cannula has annularly opposed flat notches. The disengaging means consists of means on the outer cannula for spreading the opposed flanges during rotational motion of the mating means about a longitudinal axis of the tubular member.
Known child tracheotomy tubes have a tubular extension on their trailing end. For such tracheotomy tubes, the coupling tubular member has a first means for mating the leading end of the tubular member in the pneumatic flow path with the tubular extension of the tracheotomy tube by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the tracheotomy tube to prevent the leading end of the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the mating means which is operable by application of force on the mating means in other than the generally axial direction for disengaging the engaging means from the tracheotomy tube to permit the tubular member to axially displace from the tubular extension of the tracheotomy tube. The mating means consists of a nozzle insertable into the tubular extension. The engaging means consists of a clamshell, the clamshell and the tubular extension having complementary three-dimensional surfaces which prevent axial displacement of the clamshell from the tubular extension gripped therein. Half of the clamshell has diametrically opposite lugs and another half of the clamshell has diametrically opposite fingers which resiliently snap over the lugs when the clamshell is closed. The disengaging means consists of means on the fingers for spreading the fingers in response to inward radial pressure on the spreading means to release the lugs.



BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
FIG. 1 is a perspective view of a first type of known tracheotomy tube outer cannula;
FIG. 2 is a perspective view of a first embodiment of an inner cannula for use with the outer cannula of FIG. 1;
FIG. 3 is a perspective view of a first embodiment of a coupling connected to the inner cannula of FIG. 2;
FIG. 4 is a side elevation assembly view of the coupling and cannulas of FIGS. 1-3;
FIG. 5 is a top plan assembly view from the line 5-5 of FIG. 4;
FIG. 6 is a side elevation view of the assembled coupling and cannulas of FIGS. 1-3;
FIG. 7 is a perspective assembly view of the leading end adapter of the coupling of FIG. 3 and the outer cannula of FIG. 1;
FIG. 8 is a side elevation view of the assembled leading end adapter of the coupling of FIG. 3 and inner cannula of FIG. 2;
FIG. 9 is a trailing end elevation view of the assembly of FIG. 8;
FIG. 10 is a top plan view of the assembly of FIG. 8;
FIG. 11 is a leading end elevation view of the assembly of FIG. 8;
FIG. 12 is a leading end perspective view of the leading end adapter of the coupling of FIG. 3;
FIG. 13 is a trailing end perspective view of the leading end adapter of the coupling of FIG. 3;
FIG. 14 is a side elevation view of the leading end adapter of the coupling of FIG. 3;
FIG. 15 is a trailing end elevation view of the trailing end adapter of the coupling of FIG. 3;
FIG. 16 is a top plan view of the leading end adapter of the coupling of FIG. 1;
FIG. 17 is a leading end perspective view of the inner cannula of FIG. 2 and leading end adapter of the coupling of FIG. 3 in an operatively assembled condition;
FIG. 18 is a leading end perspective view of the inner cannula of FIG. 2 and leading end adapter of the coupling of FIG. 3 in a ready-to-disconnect condition;
FIG. 19 is a perspective assembly view of a second embodiment of the coupling and inner cannula in relationship to a second type of known tracheotomy tube outer cannula;
FIG. 20 is a top plan assembly view of the coupling and cannulas of FIG. 19;
FIG. 21 is a trailing end view of the leading end of the coupling of FIG. 19;
FIG. 22 is a leading end view of the leading end of the coupling of FIG. 19;
FIG. 23 is a side elevation view of the leading end of the coupling of FIG. 19;
FIG. 24 is a top plan view of the leading end of the coupling of FIG. 19;
FIG. 25 is a side elevation assembly view of the cannulas and coupling of FIG. 19;
FIG. 26 is a side elevation view of the assembled cannulas and coupling of FIG. 19;
FIG. 27 is a perspective assembly view of a third embodiment of the coupling in relationship to a third type of known tracheotomy tube;
FIG. 28 is a top plan assembly view of the coupling and tracheotomy tube of FIG. 27;
FIG. 29 is a leading end perspective view of the coupling of FIG. 27 in an open condition;
FIG. 30 is a leading end elevation view of the coupling of FIG. 27 in the open condition;
FIG. 31 is a top plan view of the leading end of the coupling of FIG. 27 in the open condition;
FIG. 32 is a side elevation view of the leading end of the coupling of FIG. 27 in the open condition;
FIG. 33 is a side elevation assembly view of the coupling and tracheotomy tube of FIG. 27;
FIG. 34 is a side elevation view of the coupling and tracheotomy tube of FIG. 27 with the leading end of the coupling in the open condition; and
FIG. 35 is a side elevation view of the assembled coupling and tracheotomy tube of FIG. 27.



While the invention will be described in connection with preferred embodiments thereof, it will be understood that it is not intended to limit the invention to those embodiments or to the details of the construction or arrangement of parts illustrated in the accompanying drawings.
DETAILED DESCRIPTION
Tracheal Inserts:
Adult tracheotomy tubes are illustrated in FIGS. 1-18, showing a tracheotomy tube with outer and inner cannulas 100 and 130 and a tapered tubular extension 139 on the trailing end of the inner cannula 130 and FIGS. 19-26, showing a tracheotomy tube with outer and inner cannulas 200 and 230 and a tapered tubular extension 223 on the trailing end of the outer cannula 200. A child's tracheotomy tube is illustrated in FIGS. 27-35. A child's tracheotomy tube has only one cannula which, for purposes of explanation of the invention is identified as an outer cannula 300.
All three known outer cannulas 100, 200 and 300 are, in some respects, substantially similar, being arced tubes 101, 201 or 301 of approximately a quarter circle extending from a leading end 103, 203 or 303 to a collar 105, 205 or 305 at the trailing end 107, 207 or 307 of the arced tube 101, 201 or 301. A cuff 109, 209 or 309 on the leading half of the arced tube 101, 201 or 301 is inflatable via an air supply line 111, 211 or 311. The arced tube 101, 201 or 301 is the tracheal insert portion of the tracheotomy tube and, once inserted, the cuff 109, 209 or 309 is inflated to hold and seal the tube 101, 201 or 301 in position in the trachea. Each of the outer cannulas 100, 200 or 300 has a neck plate 115, 215 or 315 which positions the outer cannulas 100, 200 or 300 against the patient's neck and is adapted to maximize its manipulability relative to the collar 105, 205 or 305 by connecting hinges 117 or by openings 217 or contours 317 in its body. Each of the neck plates 115, 215 or 315 also has openings 119, 219 or 319 for connection of an adjustable strap to pass around and secure the neck plates 115, 215 or 315 against the patient's neck. The adult outer cannulas 100 and 200 are comparatively hard and the child's outer cannula 300 is very soft. From the collars 105, 205 and 305 on the trailing ends of the arced tubes 101, 201 and 301 toward the trailing ends of the outer cannulas 100, 200 and 300, the configurations of the outer cannulas 100, 200 and 300 are quite different.
Both inner cannulas 130 and 230 are also, in some respects, substantially similar, being arced tubes 131 or 231 of approximately a quarter circle extending from a leading end 133 or 233 to a collar 135 or 235 on a trailing end 137 or 237 of the arced tube 131 or 231. The inner cannulas 130 and 230 are inserted at their leading ends 131 and 231 into the trailing ends of their outer cannulas 100 and 200 until their trailing ends mate. From the collars 135 and 235 toward the trailing ends of the inner cannulas 130 and 230, the inner cannulas 130 and 230 are quite different.
The outer cannulas 100, 200 and 300 and their associated known inner cannulas have mechanisms which positively engage them against separation in their mated condition. They all present tapered tubular extensions for connection with known flexible connectors. The connection to known flexible connectors is universally accomplished by mere insertion of a tapered end of a tube into a constant diameter tube. The following illustrated embodiments of the outer cannulas 100, 200 and 300 are substantially the same as the known outer cannulas. The illustrated embodiments of the inner cannulas 130 and 230 and the flexible connectors or couplings 160, 260 and 360 are substantially different from the known inner cannulas and connectors so as to permit a positive engagement of the outer cannulas with their flexible connectors. However, they have been configured to work with the known outer cannulas 100, 200 and 300. The principles of the invention, however, are fully applicable to the connection of flexible connectors to outer cannulas other than those herein illustrated.
First Adult Tracheotomy Tube Embodiment:
Looking now at FIGS. 1-18, the first type of adult tracheotomy tube is illustrated. As best seen in FIG. 1, the collar 105 on the outer cannula 100 has an annular ring 121 which is concentric about the trailing end 107 of the outer cannula tube 101 and has top and bottom quarter arcs 123 which extend concentrically on and in a trailing direction from the ring 121. A concentric groove 125 is also provided in the face of the trailing end 107 of the outer cannula tube 101.
Looking at FIGS. 1-3 and 8-11, the inner cannula 130 applies the principles of the invention to the outer cannula 100. A soft arced tube 131 extends upwardly and rearwardly from its leading end 133 to a hard collar 135 on its trailing end 137. The collar 135 tapers outwardly to a wider, concentric, hard, tapered tubular extension 139 which extends in a trailing direction from the collar 135. The extension 139 tapers toward its trailing end face 141. The collar 135 has a pair of diametrically opposed latches 143, as shown appearing at approximately the 2 and 8 o'clock orientations when looking at the trailing end face 141 of the inner cannula 130. The latches 143 have fingers 145 which extend radially inwardly therefrom for engagement against the trailing face of the annular ring 121 on the trailing end 103 of the outer cannula 100. The fingers 145 extend in the leading end direction from resiliently flexible supports 147 on the collar 135. Squeeze plates 149 extend in the trailing end direction from the fingers 145. The leading faces 151 of the fingers 145 are beveled so that, as the inner cannula 130 is inserted into the outer cannula 100 and the beveled faces contact the annular ring 121, the supports 147 flex to widen the distance between the fingers 145. Once the fingers 145 pass over the annular ring 121, the supports return to their unbiased condition in which the trailing faces of the fingers 145 engage the leading face of the ring 121, thus locking the inner cannula 130 in place on the outer cannula 100. The squeeze plates 149 provide suitable surfaces and leverage for the thumb and forefinger to apply pressure to flex the support 147 and spread the fingers 145 so that the fingers 145 can be disengaged from the annular ring 121. The squeeze plates 149 have alignment indicia such as arrows 153, as shown diametrically opposed and pointing in the trailing end direction. As best seen in FIGS. 6, 8, 9, 11, 17 and 18, the collar 135 also has diametrically opposed rotational and longitudinal ramps 155 and 157 and longitudinal beads 159 for reasons hereinafter explained.
Looking at FIGS. 1-16, the flexible connector 160 for use with the above outer and inner cannulas 100 and 130 has a leading end adapter 161, best seen in FIGS. 5, 7 and 12-15. The leading end adapter 161 has a hard outer sleeve 167 with a soft tube liner 169. The trailing end 171 of the sleeve 167 is of narrower diameter so as to provide a connecting ring 173 for reasons hereinafter explained. The outer sleeve 167 has diametrically opposed posts 175 on its wide circumference at the leading end of the connecting ring 173. A pair of diametrically opposed resiliently flexible arms 177 extend longitudinally from the sleeve 167 to radially inwardly extending fingers 179. The sleeve 167 also has alignment indicia such as arrows 181 pointing in the leading end direction. The flexible connector 160 is in proper rotational orientation for connection to the outer and inner cannulas 100 and 130 when the arrows 153 on the inner cannula 130 are aligned with the arrows 181 on the connector sleeve 167. As best seen in FIG. 6, when the arrows 153 and 181 are aligned, the connector arms 177 can pass under the squeeze plates 149 of the inner cannula latches 143 with the flexible connector fingers 179 at approximately the 4 and 10 o'clock orientations. This positions the connector fingers 179 on the clockwise side of the rotational and longitudinal ramps 155 and 157 when the connector 160 is connected to the outer and inner cannulas 100 and 130. The leading faces 183 of the connector fingers 179 are beveled so that, as the flexible connector 160 is moved longitudinally into the tapered tubular extension 139 of the inner cannula 130, the fingers 179 will be spread apart by and slide across the ring 121, on the outer cannula 100. Once the fingers 179 pass the ring 121 they resiliently close to secure the flexible connector 160 to the outer cannula 100. The inner cannula collar 135 is sandwiched between them.
As best seen in FIG. 12, the interior surfaces of the connector arms 177 are provided with longitudinal grooves 185 and the counterclockwise inside edges of the connector arms 177 are provided with longitudinal bevels 187. To remove the flexible connector 160 from the outer and inner cannulas 100 and 130, the connector 160 is rotated counterclockwise, as indicated by the rotational arrows 189, using the thumb and forefinger on the posts 175. As the connector 160 rotates, the longitudinal bevels 187 on the connector arms 177 ride on the rotational ramps 155 on the inner cannula collar 135 to unlatch the connector fingers 179 from the collar 135. The rotation is limited to the point of abutment of the inner cannula and connector fingers 145 and 179, whereupon longitudinal beads 159 on the inner cannula collar 135 and grooves 185 on the connector arms 177 engage to provide an audible click indicating that the connector 160 can be longitudinally displaced and disconnected from the outer and inner cannulas 100 and 130. As the connector 160 is withdrawn in the trailing direction, the connector fingers 179 ride on the longitudinal ramp 157 of the inner cannula collar 135 to assure that the connector fingers 179 cannot relatch during the process.
Second Adult Tracheotomy Tube Embodiment:
Turning to FIGS. 19-26, the other type of adult tracheotomy tube is illustrated. The collar 205 of the outer cannula 200 has a hard annular ring 221 which is concentric about the trailing end 207 of the outer cannula tube 201. The hard tapered tubular extension 223 of the ring 221 narrows toward the trailing end 225. Top and bottom approximately quarter notches 227 are provided in the outer circumference of the tapered tubular extension 223 at the trailing end of the ring 221.
The inner cannula 230 applies the principles of the invention to the outer cannula 200. A soft arced tube 231 extends upwardly and rearwardly from its leading end 223 to a concentric collar 235 on its trailing end 237. A tapered tubular extension 239 extends in a trailing direction from the collar 235 to a trailing end face 241 of an annular ring 243 on the extension 239. The outside wall of the extension 239 has annular ridges 245 which complement the annular grooves 229 in the inside wall of the outer cannula tapered extension 223 to secure the inner cannula 230 in place in the outer cannula 200. A pair of vertically aligned studs 247 are provided on the trailing end face 241 of the inner cannula extension 239 for reasons hereinafter explained. A concentric pull ring 249 is hinged 251 to the bottom of the end face 241 of the extensions 239 to facilitate removal of the inner cannula 230 from the outer cannula 200. An annular outer flange 253 on the midportion of the inner cannula arced tube 231 helps to hold the inner cannula tube 231 concentrically within the outer cannula tube 201.
The flexible connector 260 for use with the above outer and inner cannulas 200 and 230 has a leading end adapter 261, best seen in FIGS. 21-24. The leading end adapter 261 has a hard outer sleeve 267 with a soft tube liner 269. The trailing end 271 of the sleeve 267 is of narrower diameter so as to provide a connecting ring 273 for reasons hereinafter explained. The outer sleeve 267 has a corrugated surface 275 to facilitate manipulation of the flexible connector 260. Diametrically vertically opposed arms 277 with radially inwardly extending fingers 279 at their leading ends are defined by longitudinal slots 281 in the sleeve 267. The fingers 279 are contoured to engage in the opposed notches 227 in the outer cannula tapered tubular extension 223. As best seen in FIG. 23, valleys 283 in the inner and outer surfaces of the arms 277 at their trailing ends permit the arms 277 to flex easily. As best seen in FIGS. 21 and 22, the leading face of the connecting ring 273 of the leading end adapter 261 has notches 285 which receive the studs 247 on the trailing end face 241 of the inner cannula 230. The notches 285 extend clockwise from the point of longitudinal insertion of the studs 247 to stops 287. Counterclockwise rotation of the leading end adapter 261 of the connector 260, indicated by the rotational arrows 289 on the sleeve 267, is terminated by the studs 247 striking the stops 287. At this point, the connector arms 277 will have flexed sufficiently to disengage the connector fingers 279 from the notches 227 in the outer cannula extension 223 so that the connector 260 can be longitudinally withdrawn from the outer and inner cannulas 200 and 230.
Child Tracheotomy Tube Embodiment:
Turning to FIGS. 27-35, the child's tracheotomy tube is illustrated. As best seen in FIG. 27, the collar 305 on the soft tube 301 has a concentric annular ring 321 extending in a trailing direction with a soft tapered extension 323 extending in a trailing direction from the ring 321. The extension 323 has annular ridges 325 in its circumference and a beveled flange 327 with an annular groove 329 in its trailing end face. A hard sleeve 331 is tapered to concentrically cover the tapered extension 323. The hard sleeve 331 has a pair of annular flanges 333 at its leading end defining an annular groove 335 therebetween. When the sleeve 331 is mounted on the soft tapered extension 323, the leading face 337 of the sleeve 331 abuts the trailing end face of the ring 321 on the collar 305 and the trailing end face 341 of the sleeve 331 abuts the leading end face of the beveled flange 327 on the tapered extension 323, locking the hard sleeve 331 in place on the soft extension 323.
Looking at FIGS. 27-35, the flexible connector 360 for use with the cannula 300 has a leading end adapter 361, best seen in FIGS. 29-32. The leading end adapter 361 is a clamshell-type grip with bottom and top shells 367 and 369. The shells 367 and 369 extend from a trailing end face 371 on a trailing connecting ring 373 to a leading connecting ring 375 separated by a narrower body 377. As best seen in FIG. 35, the shells 367 and 369 are defined by a radial cut 379 splitting the top half of the trailing connecting ring 373 and a horizontal diametric cut 381 extending from the radial cut 379 through the leading connecting ring 375. The shells 367 and 369 are hinged 383 at the top of the radial cut 379. The leading connecting ring 375 has grooves 385 defining a ridge 387 which will engage in the groove 335 on the leading end of the hard sleeve 331 mounted on the soft tapered tubular extension 323 of the cannula 300. A tapered nozzle 397 extends in a leading direction from the leading face of the trailing connecting ring 373. The nozzle 397 has an annular bead 399 on the perimeter of its leading face. A concentric bead 401 is provided on the leading face of the trailing connecting ring 373 around the nozzle 397. The annular bead 399 on the nozzle 397 abuts the inside wall of the soft tapered tubular extension 323 of the cannula 300 and the concentric bead 401 on the leading connecting ring 375 seats in the groove 329 on the leading face on the beaded flange 327 of the soft tapered tubular extension 323 of the cannula 300 when the soft extension 323 with the hard sleeve 331 are longitudinally inserted into the clamshell of the connector 360. As best seen in FIGS. 29-32, flexibly resilient supports 403 extend radially outwardly from the top shell portion of the body 377 at the diametric cut 381. Arms 405 extend downwardly, considering the clamshell in the closed condition of FIG. 35, from each of the supports 403 to fingers 407 which extend diametrically inwardly from the arms 405. The fingers 40 have beads 409 on their upper inside edges. The arms 405 also extend upwardly from the supports 403 to corrugated squeeze plates 411 which aid in manually flexing the arms 405 between the thumb and forefinger. To cooperate with the fingers 407, L-shaped lugs 413 extend upwardly, again considering the clamshell in the closed condition of FIG. 35, from the bottom shell portion of the body 377 at the diametric cut 381. When the top shell 369 is closed on the bottom shell 367, the fingers 407 snap under the lugs 413 and the beads 409 engage the inside edges of the lugs 413 to assure a stable engagement.
Common Connector Components:
Each of the flexible connectors 160, 260 and 360 has its own unique leading end adapter 161, 261 and 361 as above described. The trailing end adapters 163, 263 and 363 and intermediate tubes 165, 265 and 365 are substantially the same. Each of the intermediate tubes 165, 265 and 365 has a hard annular seat 191, 291 and 391 at its leading end. The connecting ring 173, 273 and 373 at the trailing end of each leading end adapter 161, 261 and 361 fits in and is fixed to the seat 191, 291 and 391 of the leading end of the intermediate tube 165, 265 and 365, as by ultrasonic welding. The trailing end adapters 163, 263 and 363 have hard tubular extensions 193, 293 and 393 with annular flanges 195, 295 and 395 to facilitate manipulation of the connectors 160, 260 and 360 during attachment to the ventilator. The trailing end adapters 161, 261 and 361 are fixed to the trailing ends of their intermediate tubes 165, 265 and 365, also as by ultrasonic welding.
Common Operational Features of the Embodiments:
For each of the different tracheotomy tube outer cannulas 100, 200 and 300, the corresponding coupling 160, 260 and 360 has a leading end adapter 161, 261 and 361 which interlocks with its respective tracheotomy tube outer cannulas 100, 200 and 300 preventing them from inadvertently axially displacing from each other. However, non-axial force applied to the unlatching mechanisms disengage the associated adapters 161, 261 and 361 from its tracheotomy tube outer cannula 100, 200 and 300 so that the coupling 160, 260 and 360 can be axially displaced without exertion of excessive axial force on the system and the patient.
Thus, it is apparent that there has been provided, in accordance with the invention, a ventilator to tracheotomy tube coupling that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.

## Claims

1. A coupling for extending a pneumatic flow path from a trailing end of an inner cannula inserted into a trailing end of an outer cannula of a tracheotomy tube, the inner cannula having a tubular extension on a trailing end thereof and the trailing end of the outer cannula having radially opposed flanges, the coupling comprising:
a lengthwise-extendible tubular member;
an adapter on a leading end of said lengthwise-extendible tubular member mating said leading end of said lengthwise-extendible tubular member in the pneumatic flow path to the tubular extension of the inner cannula by motion of said adapter in a generally axial direction relative to the tubular extension of the inner cannula;
opposed resiliently snapping connectors on said adapter engaging, during motion of said adapter in the generally axial direction relative to the tubular extension of the inner cannula, against the flanges of the trailing end of the outer cannula with the trailing end of the inner cannula between said adapter and the trailing end of the outer cannula to prevent said adapter from axially displacing from the tubular extension of the inner cannula after mating; and
ramps positioned on the trailing end of the inner cannula to spread said resiliently flexible connectors during rotational motion of said adapter about a longitudinal axis of said lengthwise-extendible tubular member to permit said adapter to axially displace from the tubular extension of the inner cannula.