Abstract:
A laryngeal mask of the type used to facilitate lung ventilation and the insertion of endotracheal tubes or related medical instruments through a patient&#39;s laryngeal opening as used during general anesthesia, intensive care, or critical patient care. The mask includes an inflatable positioning shield formed to fit within a patients oropharynx and seal around the circumference of the laryngeal opening, the shield having an inflatable annular toroid peripheral portion, a contoured rear portion, and a recessed front. The mask also includes a flexible respiratory tube having a proximal end lumen, a gently curved tubular body of sufficient size to permit passage of endotracheal tubes, and related medical instruments, and a distal end passing through and secured to the proximal edge of the annular toroid peripheral portion. The distal end of the tube terminates at the distal lumen within the recessed front of the inflatable positioning shield such that tubes and instruments passing through the flexible respiratory tube will be directed into the laryngeal opening. An adapter for use with medical devices is also disclosed. The adapter includes a body, a first end, a second end, and a passage therethrough wherein one end has an elliptical cross-section.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application is a continuation-in-part of U.S. application Ser. No. 09/179,928 filed on Oct. 27, 1988, which is a divisional of U.S. Pat. No. 5,937,860 issued on Aug. 17, 1999.  
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    This invention relates to an artificial airway device designed to facilitate lung ventilation and the insertion of endotracheal tubes or related medical instruments into the laryngeal opening of an unconscious patient.  
           [0004]    In general, laryngeal masks allowing for both rapid lung ventilation and the insertion of medical instruments and tubes into the laryngeal openings of patients have been described in patents such as Brain, U.S. Pat. No. 4,509,514. Consisting of two essential parts, a breathing tube and an inflatable mask, these instruments or devices are inserted blindly into a patient&#39;s throat, and when properly positioned, terminate at the laryngeal opening. A seal is then formed around the circumference of the laryngeal opening by the inflation of a ring-like structure located on the front of the mask. Inflation of the ring exerts pressure against both the front and rear portions of the oropharynx, securing the device in place such that the laryngeal opening is positioned within a recessed cavity in the mask face. Extending from a point external to the oral cavity, the flexible breathing tube terminates within the recessed cavity, aligned axially with the laryngeal opening. The positioning of the flexible breathing tube allows the passage of small diameter endotracheal tubes or related medical instruments into the laryngeal opening, in addition to allowing for lung ventilation.  
           [0005]    It has been discovered that laryngeal masks of the above-mentioned type have superior performance if its associated respiratory tube has an elliptical cross-section. This shape, however, can present a problem, since medical tubing (including the tubing for connecting to respiratory tubes) is typically circular in cross-section. This mismatch can create connection problems, leakage problems or even disconnections.  
         SUMMARY OF THE INVENTION  
         [0006]    Among the several objects and advantages of the present invention include:  
           [0007]    The provision of a new and improved laryngeal mask for the facilitation of lung ventilation and the insertion of endotracheal tubes and related medical instruments into the laryngeal opening;  
           [0008]    The provision of the aforementioned laryngeal mask which includes an adapter for connection to medical instruments or devices, wherein the adapter includes at least one end that has an elliptical cross-section; and  
           [0009]    The provision of the aforementioned laryngeal mask which includes an adapter for connection to medical instruments or devices, which includes raised ribs disposed circumferentially about the adapter for positioning of tubing.  
           [0010]    Other objects will be in part apparent and in part pointed out hereinafter.  
           [0011]    Briefly, a laryngeal mask of the present invention includes an inflatable positioning shield formed to fit within a patient&#39;s oropharynx and seal around the circumference of the laryngeal opening. The shield has a recessed front to securely surround the trachea after inflation, preventing lateral movement of the laryngeal mask. The mask also includes a flexible respiratory tube having a proximal end, a distal end, a gently curved tubular body of sufficient size to permit passage of endotracheal tubes, and related medical instruments, and a lumen therethrough terminating within the recessed front of the inflatable positioning shield such that tubes and instruments passing through the flexible respiratory tube are directed into the laryngeal opening. The flexible respiratory tube has an elliptical cross-section, facilitating insertion of the laryngeal mask through the oral cavity. An adapter is coupled to the proximal end of the respiratory tube for connection of medical instruments or devices, the adapter including a body having a first end, a second end and a passage therethrough. The first end of the adapter has an elliptical cross-section for communication with the lumen of the flexible respiratory tube, and said second end has a cross-section which differs from the cross-section of the first end.  
           [0012]    In a second aspect of the present invention, a laryngeal mask includes an inflatable positioning shield formed to fit within a patient&#39;s oropharynx and seal around the circumference of the laryngeal opening, said shield having an inflatable annular toroid peripheral portion, a contoured rear portion, and a distal front portion. The mask also includes a flexible respiratory tube having proximal and distal ends, and a lumen therebetween defined by a gently curved tubular body. The distal end of the respiratory tube terminates within the front of the inflatable positioning shield such that tubes and instruments passing through the flexible respiratory tube are directed into the laryngeal opening. The flexible respiratory tube has an elliptical cross-section facilitating insertion of the laryngeal mask through the oral cavity. An adapter is coupled to the proximal end of said respiratory tube for connection of medical instruments or devices, said adapter comprising a body having a first end that has an elliptical cross-section, a second end that has a circular cross-section, a wall member disposed substantially centrally between said first end and said second end, and a passage therethrough.  
           [0013]    In a third aspect of the present invention an adapter of the type suitable for connection of medical instruments or devices includes a body having a first end, a second end, and a passage therethrough. The first end has an elliptical cross-section for connection of tubing having an elliptical cross-section, and the second end has a cross-section that differs from the cross-section of the first end.  
           [0014]    In a fourth aspect of the present invention, an adapter of the type suitable for connection of medical instruments or devices includes a body having a first end, a second end, a wall member disposed substantially centrally between said first end and said second end, and a passage therethrough. The first end has an elliptical cross-section for connection of tubing of a first kind and at least one raised rib disposed circumferentially around an external portion of said first end. The second end has a circular cross-section for attachment of tubing of a second kind.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    In the drawings,  
         [0016]    [0016]FIG. 1 is a top view of the laryngeal mask illustrating the flexible breathing tube and the inflatable positioning shield;  
         [0017]    [0017]FIG. 1A is a cross-sectional view taken along line  1 A- 1 A in FIG. 1;  
         [0018]    [0018]FIG. 2 is a side view of the inflatable positioning shield after inflation;  
         [0019]    [0019]FIG. 3 is a sectional view of the inflatable positioning shield after inflation, taken along line  3 - 3  of FIG. 1;  
         [0020]    [0020]FIG. 4 is bottom view of the inflatable positioning shield;  
         [0021]    [0021]FIG. 5 is a sectional view of the inflatable positioning shield after inflation, taken along line  5 - 5  of FIG. 4, illustrating the recessed front of the positioning shield and the unobstructed distal lumen of the flexible breathing tube;  
         [0022]    [0022]FIG. 6 is a rear view of the inflatable positioning shield after inflation, with the flexible breathing tube removed;  
         [0023]    [0023]FIG. 7 is an artists rendition of a patient&#39;s oral cavity, illustrating the elliptical nature of the opening into the oropharynx region;  
         [0024]    [0024]FIG. 8 is a plan view of the endotracheal tube retainer, illustrating the soft cap portion;  
         [0025]    [0025]FIG. 9 is a plan view of the endotracheal tube retainer, illustrating the separation of the tube retainer body from the connection adapter;  
         [0026]    [0026]FIG. 10 is a front view of the distal end of the connection adapters, illustrating the air-flow grooves;  
         [0027]    [0027]FIG. 11 is a plan view of the laryngeal mask of the present invention during use, showing interaction with an endotracheal tube and the endotracheal tube retainer;  
         [0028]    [0028]FIG. 12 is a plan view of endotracheal tube retainer during use, illustrating proper position of the tube retainer within an endotracheal tube;  
         [0029]    [0029]FIG. 13 is a plan view of the laryngeal mask during removal, illustrating the operation of the endotracheal tube retainer; and  
         [0030]    [0030]FIG. 14 is a plan view of the adapter of the present invention illustrating the first end having an elliptical cross-section and ribs disposed therein, the wall portion, and the second end having a circular cross-section;  
         [0031]    [0031]FIG. 15A is a side cross-sectional view of the adapter of FIG. 14;  
         [0032]    [0032]FIG. 15B is a top cross-sectional view of the adapter of FIG. 14;  
         [0033]    [0033]FIG. 15C is a front view of the adapter, illustrating the gradual reduction in inside diameter between the first and second ends of the adapter.  
     
    
       [0034]    Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.  
       DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]    The following detailed description illustrates the invention by way of example and not by way of limitation.  
         [0036]    Referring to the drawings, and particularly FIGS.  1 - 3  inclusive, a removable laryngeal mask is shown generally at  20 . The laryngeal mask  20  comprises an inflatable positioning shield  22  secured to the distal end  24  of a respiratory tube  26 , forming a smooth arcuate curve as shown in FIG. 3. Composed of a flexible silicone-rubber polymer, respiratory tube  26  has an elliptical cross-section (see FIG. 1A), approximating, for ease of insertion, the shape of the human throat shown in FIG. 7. Capable of spreading radially, respiratory tube  26  can accommodate the passage of cuffed endotracheal tubes and related medical instruments or devices up to 8.0 French in diameter. The length of respiratory tube  26  is such that when the laryngeal mask  20  is properly positioned for use within the oropharynx, the attachment end  28  of respiratory tube  26  is located exterior to the oral cavity. The attachment end  28  of the respiratory tube  26  terminates in an unobstructed proximal lumen  30 , providing a direct pathway through the respiratory tube  26  to the distal end  24  and distal lumen  32 . In alternative embodiments, the attachment end  28  may be fitted with adapters or connectors (see FIGS. 14 and 15A-C) suitable for connection to a variety of medical instruments or devices, for example, lung ventilation machines.  
         [0037]    The distal end  24  is the continuous portion of respiratory tube  26  which has passed through an airtight peripheral seal  34  at the rear of the inflatable positioning shield  22 , and into the shield recess  36 . The distal end  24  terminates at an angle to its length, forming the elongated elliptically shaped distal lumen  32  open to the interior of the shield recess  36 . The elongated lower surface of the distal end forms the shield support  37 , and provides a semi-rigid structure onto which the positioning shield  22  is secured. Numerous ventilation lumen  38  perforate the distal end  24  to provide alternate airways in the event the distal lumen  32  becomes obstructed during patient lung ventilation. The ventilation lumen  38  prevent the formation of a pressure differential between the shield recess  36  and flexible respiratory tube  26 . Absent a pressure differential, any object obstructing the distal lumen  32  will not become inextricably lodged within the distal end  24 .  
         [0038]    The inflatable positioning shield  22  is composed of a wedge-shaped toroid  40 , and a pliable molded posterior base  42 . Inflation of the toroid  40  is accomplished by means of a conventional inflation device (not shown), forming an ovoid shape conforming to the approximate available space in the oropharynx region. The posterior base is secured longitudinally in an airtight manner to the lower surface of the shield support  37 . The posterior base  42  forms an elongated and tapered hemisphere, best seen in FIGS.  2 - 4 . Two semi-rigid raised runners  44  formed of molded silicone rubber are positioned longitudinally parallel to each other along the lower surface of the posterior base  42 . During insertion of the laryngeal mask  20 , the raised runners  44  guide the placement of the inflatable positioning shield  22 , aid in preventing lateral movement by fitting to the rear anatomy of the oropharynx region, and facilitate placement by decreasing drag. In fluid communication with the posterior base  42 , the annular toroid  40  is secured to the peripheral upper surface of the posterior base  42 , and inflates simultaneously to form the shield recess  36 . A tracheal notch  46  is formed in the portion of the annular toroid  40  traversing the front of the inflatable positioning shield  22 , best seen in FIG. 1. The tracheal notch  46  surrounds the trachea after proper positioning and inflation of the laryngeal mask  20 , preventing lateral movement and creating a better airtight fit with the trachea.  
         [0039]    During use, the laryngeal mask  20  is inserted through the oral cavity with the annular toroid  40  fully deflated. The smooth arcuate curve of the combined respiratory tube  26  and positioning shield  22  ensures proper positioning of the laryngeal mask  20  within the anatomy surrounding the laryngeal opening. Upon proper positioning, as determined by a resistance to further forward motion, the annular toroid  40  is inflated as described above. When fully inflated, the annular toroid  40  exerts sufficient pressure against the structures of the oropharynx to form a tight seal surrounding the laryngeal opening. Positioned within the shield recess  36 , the distal lumen  32  is axially aligned with the laryngeal opening, permitting positive lung ventilation to be performed, or allowing endotracheal tubes or related medical instruments inserted through the respiratory tube  26  to exit the distal lumen  32 , directly aligned for passage into the laryngeal opening.  
         [0040]    Removal of the laryngeal mask  20  is normally the reverse of the insertion procedure described above. In some situations, however, it is desired to remove the laryngeal mask  20  without simultaneously removing or dislodging endotracheal tubes or related medical instruments or devices passing through respiratory tube  26  into the laryngeal opening. Referring generally to FIGS.  8 - 13 , removal of the laryngeal mask  20  under such circumstances is facilitated by means of a tube retainer, shown generally at  48 .  
         [0041]    Tube retainer  48  comprises a connection adapter  50 , a stylet rod  52 , and an endcap  68 . Connection adapter  50  is composed of a soft semi-rigid material forming a truncated conical structure having four equidistantly positioned longitudinal ventilation grooves  56 . Each ventilation groove  56  permits the passage of air around the connection adapter  50  after insertion within an endotracheal tube as shown generally in FIGS.  11 - 13 . The exterior surface of connection adapter  50  between each ventilation groove  56  is threaded with threads  60 . Each thread  60  is angled and shaped so as to facilitate insertion of the connection adapter  50  into an endotracheal tube by means of a longitudinally directed force applied to the adapter, but to exert a resistive force against the removal of connection adapter  50  from an endotracheal tube in opposition to an oppositely directed longitudinally applied force. Alternatively, the adapter may be screwed into place, and unscrewed, as desired. The conical nature of the connection adapter  50  permits the tube retainer  48  to fit securely within the opening of a variety of endotracheal tubes, ranging from standard size No. 6 through standard size No. 8 tubes. The size and shape may be adapted as desired to accommodate larger and/or smaller tubes. As the tube retainer  48  is inserted within the opening of an endotracheal tube, the increasing exterior diameter of the connection adapter  50  prevents insertion beyond a certain point, limited by the interior diameter of the endotracheal tube.  
         [0042]    The connection adapter  50  is secured at its base to a disk-shaped adapter base  62 . Stylet rod  52  is a semi-rigid, circular cross-section rod. The length of stylet rod  52  is sufficient to traverse the distance between a point external to a patient&#39;s oral cavity and the laryngeal opening. During the insertion of the rod retainer  48  within an endotracheal tube or related medical instrument, the end of stylet rod  52 , external to the oral cavity, consists of a softer stylet cap  68 . Of course, rod  52  may be used separately as an intubating stylet for direct visualization by unscrewing connector adapter  50  from rod  52  and placing cap  68  into the trachea directly. The soft cap  68  is designed and configured to reduce potential tracheal trauma when used as an intubating stylet.  
         [0043]    FIGS.  11 - 13  illustrate the use of the tube retainer  48  during removal of an laryngeal mask  20 . As described above, the use of a tube retainer  48  prevents the displacement of any inserted endotracheal tubes during removal of the laryngeal mask  20 . The connection adapter  50  of tube retainer  48  is secured to the stylet rod  52  and passed through the respiratory tube  26 . The connection adapter  50  partially enters the proximal opening of the inserted endotracheal tube  70  as shown in FIG. 11. The length of the stylet rod  52  is sufficient to extend beyond the oral cavity after insertion within the endotracheal tube  70 , allowing manipulation of the tube retainer as needed to ensure a secure insertion. As shown in FIG. 13, the laryngeal mask  20 , may then be removed from the oropharynx without dislodging the endotracheal tube  70  by sliding the laryngeal mask  20  along the tube retainer  48 . Tube retainer  48  allows force to be exerted through the stylet rod  52  and connection adapter  50  on the endotracheal tube  70 , resisting the tendency of the endotracheal tube  70  to withdraw from the laryngeal opening as the laryngeal mask  20  is removed. Once clear of the oral cavity, the laryngeal mask  20  is simply slid over the stylet cap  68  on the tube retainer  48 , allowing the endotracheal tube to remain in place within the patient&#39;s laryngeal opening. The stylet is then removed by unscrewing it from the endotracheal tube.  
         [0044]    In FIGS. 14 and 15, laryngeal mask  20  is connectable to a variety of medical instruments or devices, for example, lung ventilation machines having connecting tubes that have substantially circular or conical shaped cross-sections, using an adapter  80 . Referring to FIGS.  14 - 15 , the attachment end  28  (which has an elliptical cross-section, see FIG. 1A) of laryngeal mask  20  may be fitted with adapter  80  to facilitate connection to tubing of a different cross-section or configuration. During use, adapter  80  is connected to the attachment end  28  and other tubing, for example tubing from lung ventilation machines, by a friction fit.  
         [0045]    Adapter  80  is comprised of a body  82  having a first end  84 , a second end  86  and a passage  88  therethrough. First end  84  has an elliptical cross-section for communication with the attachment end  28  of respiratory tube  26  (see FIG. 1), or any other tubing having an elliptical cross-section. The outside diameter of the first end  84  is of sufficient diameter to facilitate secure attachment to the attachment end  28  or other tubing thereby forming a fluid-tight connection when adapter  80  is inserted. The body  82  of adapter  80  further includes a second end  86  having a circular cross-section. During use, second end  86  is inserted into tubing from a pre-selected medical device and held in place by a friction fit. In most cases, such tubing has a circular cross-section. Second end  86  is of sufficient outside diameter to form a fluid-tight connection with pre-selected tubing, which is beneficial to ensure proper ventilation of the patient. In one alternate embodiment, the outside diameter of the second end  86  is in the range of between about 15 mm to about 15½ mm to facilitate fitting onto standard tubing from anesthetic medical devices. As illustrated best in FIGS. 15B and 15C, body  82  gradually transitions from the first end  84  having a substantially elliptical cross-section to the second end  86  having a substantially circular cross-section, such that the first end  84  has a smaller inside diameter than the second end  86  and preferably the diameter tapers therebetween. Accordingly, the outside diameter of first end  84  is slightly smaller than the outside diameter of second end  86 .  
         [0046]    Optionally, a wall  90  is disposed on the body  82  of adapter  80 . The location of the wall  90  is not critical. However, in the embodiment shown, wall  90  is disposed substantially centrally between the first end  84  and the second end  86  of body  82  and includes the aforementioned passage  88  therethrough. The wall is adapted to enable the fitting of medical instruments or devices onto the first end  84  and second end  86  of adapter  80 . Accordingly, the wall may be any size or shape suitable to enable the fitting of medical instruments or devices on adapter  80 . Examples of shapes and sizes that are suitable for fitting of medical instruments or devices on adapter  80  include, but are not limited to disk, rectangle, circular and square shapes. During use, the wall  90  is held between the fingers and utilized to hold the adapter  80  stationary while a user maneuvers tubing onto and off of each of the first end  84  and the second end  86  of adapter  80 . The wall  90  may optionally also create a seal between the attached tubing and the adapter  80 .  
         [0047]    In one embodiment, at least one raised rib  92  is disposed circumferentially around an external portion of the first end  84  for positioning of tubing about the end  84 . The ribs  92  are adapted for positioning and retention of the attachment end  28  of respiratory tube  26  or other tubing into the adapter  80 . Accordingly, any number of raised ribs  92  may be included that are beneficial for positioning or retention of tubing onto the adapter  80 . Alternatively, adapter  80  may be attached to attachment end  28  by adhesive or the like.  
         [0048]    After the patient has recovered sufficiently, laryngeal mask  20  and any endotracheal instruments or devices can be removed from the patient and adapter  80  can be removed from the attachment end  28  of respiratory tube  26  or any other attached tubing. The adapter  80  can be cleaned and sterilized for subsequent use with another patient or with another patient.  
         [0049]    In view of the above, it will be seen that all the objects and features of the present invention are achieved, and other advantageous results obtained. The description of the invention contained herein is illustrative only, and is not intended in a limiting sense.