Abstract:
A laryngeal blade assembly for a laryngoscope includes a light pipe assembly releasably attachable to a blade, the light being disposed along a major dimension of the blade. The light pipe assembly includes a support which fixedly retains the light pipe, the support further including a bore sized for receiving a non-axially disposed engagement member of the blade. The bore includes a first receiving cavity which is sized to receive the engagement member and a contiguous second receiving cavity having a slotted portion sized to receive only an undercut portion of the engagement member. The support can be axially shifted between the first and the second contiguous cavities to effect attachment and release of the light pipe assembly in a toolless fashion.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the field of laryngoscopes, and specifically to a hand-held laryngoscope having a removable blade assembly. 
     BACKGROUND OF THE INVENTION 
     As is known, laryngoscopes are medical diagnostic instruments used to displace the tongue and epiglottis to permit a direct view of the larynx in the introduction of tracheal tubes during intubation, narcosis and other life-threatening situations. 
     Most laryngoscopes consist of a handle containing at least one battery used as a power source. A pivotable laryngeal blade assembly extends from an upper portion of the handle, the blade being pivotable to permit the blade to fold substantially flat against the handle for storage or to a deployed position for use thereof. Furthermore, the blade assembly is completely detachable from the handle. 
     At least two general types of laryngoscopes are presently known. In one version, the handle interior contains a miniature incandescent lamp and a bundle of optical fibers, defining a light pipe, guides illumination from the contained lamp to the distal end of the blade. According to a second version, a miniature lamp is not provided within the handle, but rather is disposed at the distal end of the light pipe. In each version, the light pipe is attached to the blade. 
     It is often desirable that the light pipe be removed from the laryngeal blade assembly to allow for cleaning, disinfecting, and sterilization. 
     It is a further desire to be able to remove the light pipe from the laryngeal blade assembly without the use of tools. For example, U.S. Pat. No. 4,958,624 to Stone et al. describes a light pipe assembly which is mounted to a laryngeal blade using a removable threaded fastener, requiring that a screwdriver or similar tool be utilized to effect disassembly. This removal procedure, given the totality of situations in which a laryngoscope can be used, can be both tedious and time consuming. 
     Another known instrument which is commercially available from Heine, Inc. of Germany includes a laryngeal blade having a light pipe assembly which releasably slides onto the blade in an axial direction; that is, the light pipe assembly is attached and released along the major dimension of the blade. A problem with this particular design is that the light pipe assembly may be prematurely ejected due to a sudden impact such as might occur if the blade were to be inadvertently dropped. It is also conceivable that the light pipe may also be prematurely ejected during assembly to the handle. Due to the urgency of use of these instruments in an operating theater, emergency room, or similar location, an inadvertent release of the light pipe assembly is obviously not desirable. 
     A second toolless version is described in a recently issued and commonly assigned U.S. Pat. No. 6,013,026 to Krauter et al., the entire contents of which are herein incorporated by reference. As described therein, according to a supporting block fixedly retains a light pipe. The supporting block includes a bore disposed in a direction which, when assembled to the blade assembly, is substantially perpendicular to the major dimension of the blade. A projecting engagement member of the blade engages the bore of the supporting block, the engagement member further including an undercut portion and an annular engagement member fitted within the undercut. When engaged together, the annular engagement member retains the light pipe within the laryngeal blade assembly until a predetermined holding force is exceeded. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a laryngeal blade assembly that overcomes the above-described deficiencies of the prior art. 
     It is another primary object of the present invention to provide a laryngeal blade assembly which can be easily detached from the remainder of the blade assembly without the use of tools. 
     It is yet a further object of the present invention to provide a light pipe assembly which permits selective detachment from the laryngeal blade assembly, but in which the light pipe assembly remains relatively secure to the blade and instrument handle when dropped or subjected to a jarring impact. 
     It is still a further object of the present invention to provide a laryngeal blade assembly that can be used with either an incandescent lamp and/or a fiberoptic type laryngoscope. 
     Therefore, and according to a preferred aspect of the present invention, there is provided a blade assembly for a laryngoscope comprising a laryngeal blade configured for viewing the larynx of a patient and a light pipe assembly releasably attachable to the laryngeal blade. The light pipe assembly includes a supporting block for supporting the light pipe, the supporting block having an elongated bore for receiving an engagement member of the laryngeal blade in which the elongated bore includes a pair of contiguous receiving cavities, a first receiving cavity sized for initially engaging the supporting block and a second receiving cavity having a slot which substantially locks the light pipe assembly into place on the blade. 
     The engagement member is defined by a cylindrical shaft having an undercut portion. The first receiving cavity of the bore provided in the supporting block has a diameter which is sized to receive the diameter of the cylindrical shaft while the second contiguous cavity includes a slot sized only to receive the diameter of the undercut portion. 
     According to another preferred aspect of the invention, there is disclosed a hand-held laryngoscope for the examination of the larynx comprising a handle, a laryngeal blade attachable to said handle; and a light pipe assembly attachable to said laryngeal blade such that a light pipe is disposed along a major dimension of said blade. The light pipe assembly includes a supporting block for fixedly retaining said light pipe, said supporting block having a bore which is disposed non-axially with respect to a major dimension of said laryngeal blade. The bore is sized for receiving an engagement member of the blade and includes a first receiving cavity for initially receiving the engagement member and a contiguous second receiving cavity having a slot sized for releasably attaching the light pipe assembly to the laryngeal blade. 
     According to yet another preferred aspect of the invention, there is disclosed a method for releasably attaching a light pipe assembly to a laryngeal blade, said method including the steps of: 
     engaging a projecting member of the laryngeal blade with a bore of a supporting block of said light pipe assembly sized for receiving said member, said bore including a pair of contiguous receiving cavities and in which the projecting member is engaged with a first receiving cavity; and 
     sliding the supporting block to align the projecting member with the second contiguous cavity of the bore to releasably lock the light pipe assembly to the blade. 
     An advantage of the present invention is that the light pipe assembly can easily be attached or detached from a laryngeal blade assembly without requiring tools while still maintaining a reliable connection therewith. 
     Another advantage of the present invention is that the light pipe assembly can be fitted by simply aligning the projecting member with the bore of the supporting block and using only finger pressure to complete the assembly. As such, the entire assembly and disassembly process can be completed using one hand. 
     These and other objects, advantages and features will be described in the following Detailed Description which should be read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial sectional view of a fiberoptic laryngoscope having a pivotable laryngeal blade assembly in accordance with the present invention, the blade being shown in a folded position; 
     FIG. 2 is a sectional view of the laryngoscope of FIG. 1 in a deployed or use position; 
     FIG. 3 is an exploded perspective view of the laryngeal blade assembly of FIGS. 1 and 2; 
     FIG. 4 is an assembled rear perspective view of the laryngeal blade assembly of FIGS. 1-3; 
     FIG. 5 is a partial sectional view of a conventional, standard incandescent lamp-type laryngoscope having a laryngeal blade assembly made in accordance with the present invention; 
     FIG. 6 is an exploded perspective view of the laryngeal blade assembly of FIG. 5; 
     FIG. 7 is a partial perspective view of the laryngoscope of FIG. 1, illustrating an interlocking mount on the handle for receiving the laryngeal blade assembly of FIG. 6; 
     FIG. 8 is an elevated view of the laryngeal blade assembly of FIG. 1; 
     FIG. 9 is a side perspective view of the laryngeal blade assembly of FIG. 8; 
     FIG. 10 is a partial side perspective view of the laryngeal blade assembly of FIGS. 8 and 9 with a light pipe assembly according to a preferred embodiment of the invention prior to attachment thereof; 
     FIG. 11 is an enlarged partial side elevational view of the laryngeal blade assembly following initial attachment of the light pipe assembly; and 
     FIG. 12 is a sectional view of the assembly shown in FIG.  11 . 
    
    
     DETAILED DESCRIPTION 
     Before discussing that which Applicant regards as the main features of the present invention, a discussion of the two primary types of laryngoscopes is herein provided for background purposes. In brief, the first type of laryngoscope (also herein referred to as “the fiberoptic laryngoscope”) and discussed with reference to FIGS. 1-4 , includes a fiberoptic light pipe assembly, while the second type of instrument (also herein referred to as “the incandescent lamp laryngoscope”) discussed with reference to FIGS. 5-7 includes a blade assembly which includes both a light pipe assembly having a contained miniature incandescent lamp. Each type of laryngoscope commonly includes a handle and a laryngeal blade assembly. It should be noted, however, that the handle of the first type of laryngoscope is not interchangeable with the handle of the second type of laryngoscope. In addition, each of the following embodiments is herein described using a MacIntosh-type blade assembly, though it will be readily apparent to one of sufficient skill that other blade designs, such as Miller blade assemblies among others, can easily be substituted using the inventive concepts described herein. 
     More specifically and referring to FIG. 1, the fiberoptic laryngoscope  10  includes a handle  12  and a laryngeal blade assembly  14  which is mounted on the upper portion of the handle about a pin  16  which is held in an operative position (see FIG. 2) by a latch (not shown). Slidably mounted in a tube  20  provided in an upper portion of the handle  12  is a miniature incandescent lamp  18 . The lamp  18  is disposed in relation to a battery contact  19  which electrically connects the lamp to a contained battery power source  21 . Movement of the laryngeal blade assembly  14  into the folded position of FIG. 1 releases the miniature lamp  18  from electrical connection with the contact  19 , causing the lamp to de-energize. In order to energize the miniature lamp  18 , the laryngeal blade assembly  14  is moved to its operative position (FIG. 2) which axially depresses the lamp  18  into intimate engagement with the battery contact  19 . Additional details relating to the interrelations between the handle and blade assembly are found in U.S. Pat. No. 4,958,624 to Stone et al., the entire contents of which are herein incorporated by reference. 
     Referring to FIGS. 1,  3  and  4 , the blade assembly  14  consists of a blade  22 , sometimes referred to as a spatula, which is usually made from a stainless steel or other easily sterilizable material and a fiberoptic light pipe assembly  24  which is mounted in a receiving pocket  26  formed in an interior wall  27  of the blade  22 . The blade  22  is shaped to permit passage into the throat and examination of the larynx, the blade further including a recessed proximal portion  33  having a projecting engagement member  36 . The engagement member  36  extends in a direction which is substantially perpendicular to the major dimension of the blade  22 . 
     Referring to FIGS. 1-4, the light pipe assembly  24  consists of a narrow cylindrical light pipe  29  and a supporting block  28  formed into a unitary subassembly, as shown in FIG.  3 . The light pipe  29  is bent into a generally right-angled shape and is hollow to permit the passage therethrough of a plurality of optical fibers (not shown) that are used to transmit light from the miniature lamp  18  disposed within the handle  12  to a distal end  25  of the light pipe  29 . 
     The supporting block  28  includes a top surface  30  having an opening  32  which fixedly receives the other or proximal end of the light pipe  29 . A bore  35  disposed through the side of the supporting block  28  is sized for receiving the projecting engagement member  36  of the blade  22  with the supporting block being fitted within the recessed proximal portion  33 . The bore  35  includes a pair of contiguous receiving cavities  84  and  88 , FIG. 11, to provide locking engagement. Salient features relating to the interconnection of the light pipe assembly  24  to the blade assembly  14  are described in greater detail below. 
     Referring briefly to FIGS. 3,  4 , and  7 , the supporting block  28  further includes a base portion  37  and an elongated tongue  41  extending from one end. A slot  39  cut into the base portion  37  is sized to fit onto the pin  16  which is provided within a mounting bracket  40 , shown most clearly in FIG. 7, in the upper portion of the handle  12 . A similar slot  38  is defined in the recessed proximal portion of the blade  22  for fitting to the pin  16 . The mounting bracket  40  is defined by a pair of side walls  42 , defining a spacing  43  therebetween. 
     The width of the supporting block  28  is chosen such that when mounted on the blade  22 , the overall combined width of the blade  22  and the supporting block will fit within the spacing  43  between the side walls  42  of the mounting bracket  40 , FIG.  7 . The mounting bracket  40  can be sized to fit either a fiberoptic or incandescent-type laryngeal blade assembly depending on the handle. As shown in FIGS. 1,  2  and  7 , the sides of the mounting bracket  40  are spaced in accordance with ASTM F965, ASTM F1195, ISO7376-1, ISO7376-3 and EIN 1819 standards to receive the assembly defined by the blade  22  and the supporting block  28 . 
     Thus and in operation, the described laryngeal blade assembly  14  will smoothly and snugly fit within the mounting bracket  40  when raised to the operative position shown in FIG.  2  and will force the lamp  18  into contact with the battery contact  19  in order to illuminate the lamp. The light from the miniature lamp  18  is then transmitted via the bundle of optical fibers (not shown) provided in the hollow light pipe  29  to the distal end  25  thereof to allow the desired target to be illuminated. With the laryngeal blade assembly  14  in the folded position of FIG. 2, the lamp  18  is deenergized in the manner previously described. 
     Before describing the present invention, reference is herein first made to FIGS. 5-7 which illustrate a standard incandescent lamp laryngoscope  50 . For the sake of clarity, similar parts are labeled with the same reference numerals. 
     The laryngoscope  50  includes a handle  70  and a laryngeal blade assembly  55  having a light pipe assembly  48  which is releasably attached thereto. The light pipe assembly  48  includes a hollow light pipe  54 , but in lieu of providing a bundle of optical fibers, a halogen or other suitable miniature lamp  18  is mounted into the distal end  44  of the light pipe, the distal end being further positioned within a receiving pocket  26  provided along an interior wall  27  of the blade  22 . The lamp  52  is electrically connected by a wire  62  within the hollow light pipe  54  to a contact  60  providing one side of a connection circuit with the blade  22  providing the other side of the circuit. When the laryngeal blade assembly  14  is in the operative position shown in FIG. 5, the contact  60  engages a contact button  64  which is connected to a battery power source  21  provided within the interior of the handle  70  which is urged by a spring  74  to maintain contact therewith. 
     The remainder of the light pipe assembly  48 , however, for purposes of the present invention, is identical to that previously described including a supporting block  28  which retains a proximal end  31  of the hollow light pipe  54  in fixed relation within a top surface  30  of the block. 
     As clearly shown in FIGS. 5 and 7, and as in the preceding fiberoptic laryngoscope embodiment, the upper portion of the handle  70  includes a mounting bracket  40  having a pair of spaced walls  42  sized for accommodating the supporting block  28  and the blade  22  when assembled. The block  38  and a recessed proximal portion  33  of the blade  22  further includes corresponding slots  39 ,  38 , respectively, sized to engage a pin  16  provided in the bracket  40  to provide the necessary attachment to the handle  70 . 
     Referring to FIGS. 8-12, the bore  35  of the supporting block  28  includes a pair of contiguous receiving cavities  84 ,  88  which are aligned with and positioned relative to a projecting engagement member  36  of the blade  22 . The first or upper receiving cavity  84  is substantially circular and is sized to adequately receive the diameter of the engagement member  36 . The second or lower receiving cavity  88  includes a T-shaped slot  87  which is sized to receive the diameter of an undercut portion  56  of the engagement member  36 . 
     Referring to FIGS. 8-12, the assembly of the light pipe assembly  24  to the laryngeal blade assembly  14  is herein described. Initially, the distal end  25  of the light pipe assembly  24  is placed into the receiving pocket  26  defined in the interior wall  27  of the blade  22 . In this position, the supporting block  28  is placed in substantial proximity with the engagement member  36 . The bore  35 , and more specifically the circular upper receiving cavity  84  is then aligned with and fitted to the engagement member  36 . Preferably, the thumb of the user is then placed on the bottom surface of the supporting block  28  and pushed in an upward direction  90 , causing the undercut portion  56  to be snap-fitted within the T-shaped slot  87  of the lower receiving cavity  88 . 
     After using the laryngoscope shown in FIG. 10, the blade  22  and the light pipe assembly  24  must be sanitized. Therefore, the light pipe assembly  24  must be removed from the blade assembly  14 . According to the present invention, the light pipe assembly  24  can easily be released from the blade  22  by reversing the above assembly procedure and pushing the supporting block  28  in a downward direction displacing the engagement member  36  of the blade  22  into the first receiving cavity  84 . The light pipe can then slid off the engagement member  36  and the receiving pocket  26  for cleaning. 
     In use, the light pipe assembly  24  is securely, but releasably, fastened to the laryngeal blade assembly  14 . Moreover, the described attachment is adequately secure such that the light pipe assembly will not be dislodged, even if the above assembly is dropped or subjected to an impact load. 
     PARTS LIST FOR FIGS. 1-12 
       10  fiberoptic laryngoscope 
       12  handle 
       14  laryngeal blade assembly 
       16  pin 
       18  miniature lamp 
       19  electrical or battery contact 
       20  tube 
       21  battery power source 
       22  laryngeal blade 
       24  light pipe assembly 
       25  distal end 
       26  receiving pocket 
       27  interior wall 
       28  supporting block 
       29  light pipe 
       30  top surface 
       31  proximal end 
       32  opening 
       33  recessed proximal portion 
       35  bore 
       36  engagement member 
       37  base portion 
       38  slot 
       39  slot 
       40  mounting bracket 
       41  elongated tongue 
       42  spaced walls 
       44  distal end 
       48  light pipe assembly 
       50  incandescent lamp laryngoscope 
       52  cylindrical shaft 
       54  light pipe 
       55  laryngeal blade assembly 
       56  undercut portion 
       64  contact button 
       70  handle 
       84  receiving cavity 
       87  slot 
       88  receiving cavity 
       90  direction of movement 
     While the present invention has been particularly shown and described with reference to certain particular embodiments, it should be readily apparent to one skilled in the art that various changes and variations are possible without departing from the spirit and scope of the invention as defined by the following claims.