Abstract:
A disposable tracheostomy inner cannula connector that is compatible with prior art disposable inner cannula tracheostomy tube systems. The connector has an annular ring at a proximal end thereof which allows the inner cannula to snap in the connector and thereby secure the inner cannula in place. A locking mechanism of the connector, located at the distal end, permanently affixes the outer cannula to the connector.

Description:
FIELD OF THE INVENTION 
     The present device relates to an improvement concerning tracheostomy tubes. The tracheostomy tubes are generally comprised of an outer cannula and a disposable inner cannula. 
     BACKGROUND OF THE INVENTION 
     Tracheostomy tubes are used in the health care field to provide a bypass supply of air or gases to a patient having an obstruction of the larynx or pharynx and who is thus no longer able to breath through the normal route. Tracheostomy tubes are also placed in patients who, because of injury or disease, cannot breath on their own. These patients are chronically dependant on mechanical ventilation and the long-term artificial airway of choice is the tracheostomy tube. 
     An incision is made by the doctor below the obstruction and the tube inserted. The tube then acts as a gateway, allowing the patient to breath normally, the proximal end of the tube remaining stationary outside the trachea. 
     The tracheostomy tube has a tendency to become either partially or completely obstructed, over time, by the accumulation of mucus or phlegm. To resolve this problem, a system where two cannulas are placed one inside the other has been developed, which allows for the removal of the inner cannula to facilitate cleaning while still maintaining the outer cannula in the patient&#39;s trachea, U.S. Pat. No. 3,693,634 to Shiley/Mallinckrodt. Problems may occur due to accidental disconnection of the inner and outer cannulas of the tracheostomy tube, thereby allowing for spillage and/or slippage between the two. This slippage may cause a disconnection a ventilator resulting in the death of the patient. 
     There are several devices which contain a means of connecting the inner cannula to the outer cannula and the outer cannula to the ventilation system. These include, but are not limited to, U.S. Pat. No. 3,659,612 to Shiley et al., U.S. Pat. No. 4,009,720 to Crandall, et al. and U.S. Pat. No. 3,088,466 to Nichols. Inherent in these tracheostomy tube designs is the fact that two separate connectors are required. This means that there are two disconnection points which reduces the safety of the system, the accidental disconnection of the inner cannula with the ventilation system being increased. In addition, an air tight seal must be present between the inner and outer cannula to ensure that the respiration pressure from an artificial ventilation system is maintained and leakage does not occur. Another disadvantage is that while the inner cannula is removed, the ventilator cannot be connected to the tracheostomy tube, if needed. 
     U.S. Pat. No. 4,817,598 to LaBombard discloses a disposable inner cannula tracheostomy tube with a ventilator connector that is permanently fixed to the outer cannula. The proximal end of the inner cannula fits into the inner diameter of the connector and is fixed with opposing ribs and grooves that create a “SNAP” connection. The inner cannula has a proximal ring that is connected by a hinge to provide a gripping surface for removal of the inner cannula from the outer cannula. 
     The major problem with both the LaBombard and the Shiley devices is that they are not compatible with one another. This has created a strain on consumers in the disposable inner cannula market. What is needed is a connector device which can be used in conjunction with all the available disposable inner cannulas on the market to allow interchangability of the inner cannula with the tracheostomy tube and increase its safety. Such a connector will allow the care-giver and patient to take advantage of the product benefits of the Shiley device as well as those of the LaBombard tracheostomy tube. 
     SUMMARY OF THE INVENTION 
     Wherefore, it is an object of the present invention to overcome the aforementioned problems and drawbacks associated with the prior art designs. 
     The device, according to the present invention, relates to tracheostomy tubes, in particular, those that are disposable and composed of an outer cannula and a disposable inner cannula. The device will allow for the interchangability between various manufacturers as well as allowing for the permanent attachment of the ventilator connector thus increasing safety to the patient. 
     In a preferred embodiment of the invention, the connector, used to attach the outer cannula with the inner cannula, comprises: a) a locking means; b) a standard taper; c) an annular ring; and d) securing means. The connector may be constructed from material such as polypropylene, polyethylene, polycarbonate, polyvinyl chloride or another material that is capable of maintaining rigidity during the connector&#39;s attachment. The locking means of the device projects outward from the connector&#39;s distal end and has a lip to facilitate the connector&#39;s attachment to an outer cannula. A standard 1 in 40 taper is provided on the exterior surface of the connector with a nominal outer diameter of 15 mm throughout the length of the connector. In addition, there is a compression rib attached to the distal portion of the locking means which encompasses the connector to compensate for variances in the proximal end of the connector portion of the disposable inner cannula. The annular ring has a slightly smaller diameter than the diameter of the annular protrusion of the inner cannula to provide an interference fit therebetween. 
     In another preferred embodiment, the connector is described through its use. Its use being a method of permanently attaching a connector to a tracheostomy outer cannula comprising a series of steps. First, a connector with an elongate housing must be provided, having a through bore extending longitudinally completely through the elongate housing. Then an inwardly facing annular ring must be located within the through bore, adjacent one end thereof, for facilitating engagement with a recess of an inner cannula. Finally, a locking mechanism is required on the connector for supporting the outer cannula in a locking engagement with the connector. 
     The present invention relates to a connector for interconnecting an inner cannula with an outer cannula, the connector comprising: an elongate housing defining a through bore extending longitudinally completely therethrough; an inwardly facing annular ring being located within the through bore, adjacent one end thereof, for facilitating engagement with a recess of an inner cannula; and the connector supporting a locking mechanism for facilitating a locking engagement with an outer cannula. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The device will now be described by way of example, with reference to the accompanying drawings in which: 
     FIG. 1A is a diagrammatic side elevational view of a prior art inner cannula; 
     FIG. 1B is a diagrammatic cross-sectional view of the prior art inner cannula of FIG. 1A; 
     FIG. 1C is a diagrammatic front elevational view of the prior art inner cannula of FIG. 1A; 
     FIG. 2 is a partial diagrammatic cross-sectional view of the prior art inner cannula of FIG. 1A in combination with a 15 mm connector according to the present invention; 
     FIG. 3A is a diagrammatic transverse cross-sectional view of the 15 mm connector according to the present invention; 
     FIG. 3B is a diagrammatic top elevational view of the 15 mm connector of FIG. 3A; 
     FIG. 3C is a diagrammatic bottom elevational view of the 15 mm connector of FIG. 3A; 
     FIG. 3D is a diagrammatic side elevational view of the 15 mm connector of FIG. 3A; and 
     FIG. 4 is a partial diagrammatic cross-sectional view of the prior art inner cannula of FIG. 1A located within a prior art outer cannula both coupled to the 15 mm connector according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is in no way meant to limit the scope of the connector device in size, shape, materials used in its construction, or in the orientation of the components. The 15 mm connector  2 , according to the present invention, is envisioned being made from a material including, but not limited to, polypropylene, polyethylene, polycarbonate, polyvinyl chloride or other similar materials capable of maintaining rigidity to facilitate remaining permanently attached to the outer cannula  38  of a disposable tracheostomy tube  3  once “SNAPPED” in position. The 15 mm connector  2  typically remains located on the tracheostomy tube  3  for the life of the tracheostomy tube  3  which, in most applications, is approximately thirty (30) days. 
     Turning first to FIGS. 1A-1C, a brief description concerning a known prior art inner cannula  4  will now be provided. As can be seen in these three Figures, the inner cannula  4  comprises an elongate hollow tube  6  having an interior surface  8  and an exterior surface  10  and a length of about between three and six inches. The elongate hollow tube  6  has a proximal end  12  and a distal end  14 . The proximal end  12  of the elongate tube  4  has an enlarged head  16  formed integrally therewith to facilitate securement of the inner cannula  4  to the 15 mm connector  2 , according to the present invention, and a further discussion concerning the same will follow. 
     The enlarged head  16  has an exterior annular recess  18  formed therein which is located adjacent an exterior annular protrusion  20 . The purpose of these two components will become apparent from the following discussion of the present invention. The enlarged head  16  has a handle grip  22  which separates both the annular recess  18  and the annular protrusion  20  from a remainder of the proximal end  26  of the enlarged head  16 . The handle grip  22  facilitates removal of the inner cannula  4  from the tracheostomy tube  3 , by a user, and a further discussion concerning the same will be provided below. 
     Turning now to FIGS.  2  and  3 A- 3 D, a detailed description concerning the 15 mm connector  2 , according to the present invention, and its interaction with the inner cannula  4  and the outer cannula  38  will now be provided. As can be seen in these five Figures, the 15 mm connector  2  has an elongate housing  25  which is provided with a longitudinal through bore  26  extending completely therethrough. The through bore  26  has an interior surface  28  and an exterior surface  29 . The exterior surface  29  is provided with a slight (standard) taper, e.g. a 1 in 40 slope, to facilitate connection to a ventilator system in a conventional manner. The proximal end  30  of the interior surface  28  of the 15 mm connector  2  has an inwardly facing annular ring  32  which is located to engage with and lockingly retain the annular recess  18  of the inner canula  4 . 
     Such locking retainment is achieved by passing the inner canula  4 , the distal end  14  first, in the through bore  26  until the protrusion  20  contacts the inwardly facing annular ring  32 . Further insertion of the inner canula  4 , in the same insertion direction, causes one or both of the annular ring  32  and the annular protrusion  20  to be slightly compressed as the annular ring  32  slides over the annular protrusion  20  and thereafter the annular ring  32  is received, e.g. “SNAPPED”, and retained by the annular recess  18  to lock the position of the inner canula  4  relative to the 15 mm connector  2 . 
     The distal end  31  of the 15 mm connector  2  supports a pair of opposed locking mechanisms or flexible arms  34  which are located to engage with an annular flange  36  provided on the proximal end of the hollow outer canula  38  (FIG.  4 ). The opposed flexible arms  34  have a substantially U-shaped longitudinal cross-section (see FIG.  3 A). The free end  40  of each flexible arm  34  is provided with a chamfer  42  to facilitate receiving of the annular flange  36  of the outer cannula  38  and maintain a permanent locking engagement between the outer cannula  38  and the 15 mm connector  2 . 
     A thin, flat annular seal or gasket  44 , such as an lastomeric O-ring, is provided between a flat planar end ace  46  of the 15 mm connector  2  and a mating flat planar end face  48  located on the proximal end of the outer annula  38 , e.g. on the annular flange  36 . The annular gasket  44  compensates for manufacturing and/or tolerance errors of these two components to facilitate a fluid tight sealing engagement therebetween. 
     The flexible arms  34  are sized so that when the annular flange  36  of the outer cannula  38 , as well as the annular gasket  44 , are accommodated between the U-shaped transverse cross-section of the flexible arms  34 , the annular flange  36  and the annular gasket  44  are compressed somewhat against the opposed end faces  46  and  48  to provide a fluid tight seal between the outer cannula  38  and the 15 mm connector  2 . 
     As can be seen in FIG. 4, the outer cannula  38  also comprises an elongate hollow tube  50  having an interior surface (not shown in detail) and an exterior surface  52 . The elongate hollow tube  50  also has a proximal end  54  and a distal end (not shown in detail). The elongate hollow tube  50  is sized to receive the inner cannula  4  therein, with sufficient clearance between the two cannulas  4 ,  38 , to facilitate easy relative movement therebetween. 
     The connection between the inner cannula  4  and the 15 mm connector  2  is maintained for the life of the inner cannula  4  which, on average, is about twenty-four (24) hours or so. To remove and/or replace the inner cannula  4 , a user firmly grasps the exposed handling grip  22  of the inner cannula  4 , e.g. two or more exposed ribs  56  facilitate such grasping, and pulls the inner cannula  4  with one hand while stabilizing a remainder of the tracheostomy tube  3  with the other hand. Such pulling action causes one or both of the annular ring  32  and the annular protrusion  20  to be slightly compressed, as the annular ring  32  once again slides over the annular protrusion  20 , and is released from the annular recess  18  to “unlock” the inner cannula  4  from the 15 mm connector  2 . Thereafter, the inner cannula  4  can be completely removed from the 15 mm connector  2  and a new inner cannula  4  can be inserted in place thereof in the previously discussed manner. During this replacement procedure, as well as during the entire life of the tracheostomy tube  3 , the 15 mm connector  2  remains attached to the tracheostomy tube  3 —on average the life of the tracheostomy tube  3  is about thirty (30) days. 
     FIG. 4 illustrates a diagrammatic cross sectional view of the Shiley/Mallinckrodt tracheostomy tube  3  showing the inner cannula  4  located within the outer cannula  38  with the 15 mm connector  2 , according to the present invention, interconnecting both components with one another. 
     It is to be appreciated that the locking mechanism  34  is sized to be compatible with the proximal end of the prior art Shiley/Mallinckrodt tracheostomy tube  3 . The annular ring  32  of the 15 mm connector  2  is also compatible with a prior art connector of the SIMS tracheostomy tube, which is not shown. 
     Since certain changes may be made in the above described, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.