Patent Publication Number: US-2020288961-A1

Title: Universal laryngoscope blade

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/818,484, filed Mar. 14, 2019, the content of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The invention relates to the field of laryngoscopes in general, and particularly for universal laryngoscope blades. 
     BACKGROUND 
     Laryngoscopes typically include a lamp that emits light to illuminate a field of view during intubation. The lamp for illuminating the larynx during use is attached either to the laryngoscope blade, or is provided in the handle and the blade includes a light guide that guides the light produced in the handle. Known laryngoscope blades that include the lamp are referred to herein as conventional blades. Known laryngoscope blades that include a light guide for guiding light produced from a lamp provided in the handle are referred to herein as fiber-illuminated blades. 
       FIGS. 1A-C  show views of an exemplary known conventional blade  100 .  FIG. 1A  shows a side view of the conventional blade  100 .  FIG. 1B  shows a rear view of the convention blade.  FIG. 1C  shows a magnified side view of the blade fitting  130  of the conventional blade  100 . Unless otherwise indicated, direction terms such as “top,” “bottom,” “front,” “rear,” “above,” “below,” “vertical,” “horizontal,” etc., when used to describe the position of a structure shown in the figures, are directed to the respective direction of the structure as oriented in the figures. For example, the blade fitting  130  of the conventional blade  100  (described in further detail below) is provided on the bottom of the conventional blade  100 , as oriented in  FIGS. 1A-C . Nevertheless, the direction terms used herein do not necessarily correspond to the orientation of the structure with respect to a user or a patient during intended use. 
     The conventional blade  100  includes a blade body  110 , a lamp  120 , and a blade fitting  130 . The blade fitting  130  includes a body  132 , a lock, an electrical contact  137 , and a hinge slot  134 . As shown in  FIG. 1B , the body  132  has a thickness T C . The lock includes a hinge lock  136  disposed within a bottom surface of the hinge slot  134 . The lock also includes a side lock  138  provided on a side of the body  132 . A center point of the side lock  138  is indicted at the intersection of side lock crosshairs, as shown in  FIG. 1C . The hinge lock  136  and the side lock  138  are detent mechanisms. The electrical contact  137  is provided on a bottom of the body  132 . The electrical contact  137  is in electrical communication with the lamp  120  via one or more wires that supply power to the lamp  120 . The hinge slot  134  extends into the body  132  at an angle from a front the body  132  towards a central region of the body  132  and terminates at a bearing surface  135 . The bearing surface  135  has a semicircular shape having a diameter and a virtual center point, indicated at the intersection of hinge slot crosshairs shown in  FIG. 1C , about which the bearing surface  135  forms the semicircular shape. 
     With reference to the magnified side view of the blade fitting  130  of the conventional blade  100  shown in  FIG. 1C , the center point of the side lock  138  is spaced from the virtual center point of the semicircular bearing surface  135  by a distance having a horizontal distance component D CL_h , and a vertical distance component D CL_v . The center point of the side lock  138  is spaced rearwardly from the virtual center point of the semicircular bearing surface  135  by the horizontal distance component D CL_h , and is spaced below the virtual center point of the bearing surface  135  by the vertical distance component D CL_v . 
       FIGS. 2A-C  show views of an exemplary known conventional handle  200 .  FIG. 2A  shows a perspective view of the conventional handle  200 .  FIG. 2B  shows a top view of a hook-on fitting  210  of the conventional handle  200 .  FIG. 2C  shows a cut-away side view of the hook-on fitting  210  of the conventional handle  200  taken along section B-B of  FIG. 2B . 
     The conventional handle  200  includes a grip  202  and a hook-on fitting  210  disposed at a top of the grip  202 . The grip  202  is configured to be grasped by the hand of a user of the laryngoscope. The conventional handle  200  also includes one or more batteries disposed within an interior of the grip  202 . The one or more batteries serve as a power source for the lamp  120  of the conventional blade  100 . 
     The hook-on fitting  210  of the conventional handle  200  is specifically designed for attachment to the blade fitting  130  of the conventional blade  100 , and vice versa. The hook-on fitting  210  includes an electrical contact  212 , first and second side supports  214   a ,  214   b , and a hinge pin  218 . The electrical contact  212  is in electrical communication with the batteries via one or more wires that supply power to the electrical contact  212 . The electrical contact  212  is configured to supply power to the electrical contact  137  of the blade fitting  130  of the conventional blade  100  when the conventional blade  100  is engaged with the conventional handle  200  in an operating position. 
     The first and second side supports  214   a ,  214   b  extend vertically from the top of the grip  202 . The first and second side supports  214   a ,  214   b  extend parallel to each other and are spaced apart from each other. The space bounded within the top of the grip  202  and the first and second side supports  214   a ,  214   b  forms a seat  219 . The seat  219  has a width W C  between the first and second side supports  214   a ,  214   b . The width W C  is greater than the thickness T C  of the body  132  of the blade fitting  130  such that the seat  219  is configured to receive the body  132  of the blade fitting  130  therein. 
     The hinge pin  218  is attached to (i.e., extends through) the front of each of the first and second side supports  214   a ,  214   b  and extends across the seat  219 . The hinge pin  218  is a cylinder having a diameter d C . The diameter d C  is less than the diameter of the semicircular bearing surface  135  of the blade fitting  130  such that the hinge pin  218  is configured to be received within, and be rotatably supported by, the hinge slot  134  of the conventional blade  100 . The hinge lock  136  is configured to lock the hinge pin  218  within the hinge slot  134 . 
     At least one of the side supports includes a lock slot protruding into a seat-facing side of the respective side support. For example, the first side support  214   a  includes a first lock slot  216   a  and the second side support  214   b  includes a second lock slot  216   b  (shown in  FIG. 9C ). The lock slot is configured to receive the side lock  138  of the blade fitting  130  to hold the body  132  within the seat  219 . To ensure that the side lock  138  fits within the lock slot when the conventional blade  100  is engaged with the conventional handle  200 , a center of each respective lock slot is spaced from a center point of the hinge pin  218 , designated by the intersection of the hinge pin crosshairs shown in  FIG. 2C , by a distance having a horizontal distance component D CLS_h , and a vertical distance component D CLS_v . The center of each respective lock slot is spaced rearwardly from the center point of the hinge pin  218  by the horizontal distance component D CLS_h , and is spaced below the center point of the hinge pin  218  by the vertical distance component D CLS_v . 
     The blade fitting  130  of the conventional blade  100  is configured to engage with hook-on fitting  210  of the conventional handle  200  to lock the conventional blade  100  within the conventional handle  200  in an operating position, in which the laryngoscope is ready-for-use. To place the conventional blade  100  in the operating position, the blade fitting  130  is first attached to the hook-on fitting  210 . The blade fitting  130  is attached to the hook-on fitting  210  by placing the hinge pin  218  of the hook-on fitting  210  within the hinge slot  134  of the blade fitting  130  and providing relative movement between the hinge pin  218  and the hinge slot  134  until the hinge pin  218  abuts against the semicircular bearing surface  135  of the hinge slot  134  and is locked therein by the hinge lock  136 . Relative rotational movement is provided between the conventional blade  100  and the conventional handle  200  such that the hinge slot  134  and the hinge pin  218  are rotated relative to one and other until the body  132  of the blade fitting  130  slides within the seat  219  of the hook-on fitting  210 . After the body  132  of the blade fitting  130  is fully received within the seat  219  of the hook-on fitting  210 , the side lock  138  of the blade fitting  130  engages with the lock slot of the hook-on fitting  210 . The conventional blade  100  is thus locked within the conventional handle  200  in the operating position. In the operating position, the electrical contact  137  of the blade fitting  130  is engaged with the electrical contact  212  of the hook-on fitting  210 , and the laryngoscope is ready-for-use. 
       FIGS. 3A-C  show views of an exemplary known fiber-illuminated blade  300 .  FIG. 3A  shows a side view of the fiber-illuminated blade  300 .  FIG. 3B  shows a rear view of the fiber-illuminated blade  300 .  FIG. 3C  shows a magnified side view of the blade fitting  330  of the fiber-illuminated blade  300 . 
     The fiber-illuminated blade  300  includes a blade body  310 , a light guide  320 , and a blade fitting  330 . The blade fitting  330  includes a body  332 , a lock, a light guide interface  339 , and a hinge slot  334 . As shown in  FIG. 3B , the body  332  has a thickness T F . The lock includes a hinge lock  336  disposed within a top surface of the hinge slot  334 . The lock also includes first and second side locks  338   a ,  338   b  respectively provided on opposite sides of the body  332 . A center point of the second side lock  338   b  is indicted at the intersection of side lock crosshairs, as shown in  FIG. 3C . The hinge lock  336  and the first and second side locks  338   a ,  338   b  are detent mechanisms. The light guide interface  339  is an end of the light guide  320  that is provided on a bottom of the body  332 . The light guide interface  339  is configured to interface with an optical pathway  412  of a fiber-illuminated handle  400  (described below) to receive light transmitted from a lamp disposed within the fiber-illuminated handle  400 . The hinge slot  334  extends into the body  332  at an angle from a front the body  332  towards a central region of the body  332  and terminates at a bearing surface  335 . The bearing surface  335  has semicircular shape having a diameter and a virtual center point, indicated by the intersection of hinge slot crosshairs shown in  FIG. 3C , about which the bearing surface  335  forms the semicircular shape. 
     With reference to the magnified side view of the blade fitting  330  of the fiber-illuminated blade  300  shown in  FIG. 3C , a center of the hinge lock  336  is spaced forwardly from the virtual center of the semicircular bearing surface  335  by a horizontal distance H FHL . The center point of the second side lock  338   b  is spaced from the virtual center point of the semicircular bearing surface  335  by a distance having a horizontal distance component D FL_h , and a vertical distance component D FL_v . The center point of the second side lock  338   b  is spaced rearwardly from the virtual center point of the semicircular bearing surface  335  by the horizontal distance component D FL_h , and is spaced below the virtual center point of the bearing surface  335  by the vertical distance component D FL_v . A center point of the first side lock  338   b  is provided at a corresponding position at the other side surface of the body  332  with respect to the virtual center point of the semicircular bearing surface  335  such that the first and second side locks  338   a ,  338   b  are spaced the same distance from the virtual center point of the semicircular bearing surface  335 . 
       FIGS. 4A-C  show views of an exemplary known fiber-illuminated handle  400 .  FIG. 4A  shows a perspective view of the fiber-illuminated handle  400 .  FIG. 4B  shows a top view of the hook-on fitting  410  of the fiber-illuminated handle  400 .  FIG. 4C  shows a cut-away side view of the hook-on fitting  410  of the fiber-illuminated handle  400  taken along section A-A of  FIG. 4B . 
     The fiber-illuminated handle  400  includes a grip  402  and a hook-on fitting  410  disposed at a top of the grip  402 . The grip  402  is configured to be grasped by the hand of a user of the laryngoscope. The fiber-illuminated handle  400  also includes one or more batteries, the lamp, and an optical pathway  412 . The one or more batteries serve as a power source for the lamp provided within the fiber-illuminated handle  400 . The optical pathway  412  supplies light, emitted from the lamp, to the light guide interface  339  of the fiber-illuminated blade  300  when the fiber-illuminated blade  300  is connected to the fiber-illuminated handle  400  in an operating position, described below. 
     The hook-on fitting  410  of the fiber-illuminated handle  400  is specifically designed for attachment to the blade fitting  330  of the fiber-illuminated blade  300 , and vice versa. The hook-on fitting  410  includes an end of the optical pathway  412 , first and second side supports  414   a ,  414   b , and a hinge pin  418 . The first and second side supports  414   a ,  414   b  extend vertically from the top of the grip  402 . The first and second side supports  414   a ,  414   b  extend parallel to each other and are spaced apart from each other. The space bounded within the top of the grip  402  and the first and second side supports  414   a ,  414   b  forms a seat  419 . The seat  419  has a width W F  between the first and second side supports  414   a ,  414   b . The width W F  is greater than the thickness T F  of the body  332  of the blade fitting  330  such that the seat  419  is configured to receive the body  332  of the blade fitting  330  therein. 
     The hinge pin  418  is attached to (i.e., extends through) the front of each of the first and second side supports  414   a ,  414   b  and extends across the seat  419 . The hinge pin  418  is a cylinder having a diameter d F . The diameter d F  is less than the diameter of the semicircular bearing surface  335  of the blade fitting  330  of the fiber-illuminated blade  300  such that the hinge pin  418  is configured to be received within, and be rotatably supported by, the hinge slot  334 . The hinge lock  336  is configured to lock the hinge pin  418  within the hinge slot  334 . 
     The first and second side supports  414   a ,  414   b  respectively include first and second lock slots  416   a ,  416   b  that protrude into a seat-facing side of the respective side support (the second lock slot  416   b  is shown in  FIG. 11C , discussed below). The first and second lock slots  416   a ,  416   b  are configured to receive a respective one of the first and second side locks  338   a ,  338   b  of the blade fitting  330  to hold the body  332  within the seat  419 . The first and second lock slots  416   a ,  416   b  are each respectively positioned with respect to a center point of the hinge pin  418  to ensure that the first and second side locks  338   a ,  338   b  fit within respective ones of the first and second lock slots  416   a ,  416   b  when the fiber-illuminated blade  300  is engaged with the fiber-illuminated handle  400  in the operating position. As shown in  FIG. 4C , a center of the first lock slot  416   a  is spaced from the center point of the hinge pin  418 , designated at the intersection of the hinge pin crosshairs, by a distance having a horizontal distance component D FLS_h , and a vertical distance component D FLS_v . The center of the first lock slot  416   a  is spaced rearwardly from the center point of the hinge pin  418  by the horizontal distance component D FLS_h , and is spaced below the center point of the hinge pin  418  by the vertical distance component D FLS_v . A center point of the second lock slot  416   b  is provided at a corresponding position at the seat-facing side of the second side support  414   b  with respect to the center point of the hinge pin  418  such that the first and second lock slots  416   a ,  416   b  are spaced the same distance from the center of the hinge pin  418 . 
     The blade fitting  330  of the fiber-illuminated blade  300  is configured to engage with hook-on fitting  410  of the fiber-illuminated handle  400  to lock the fiber-illuminated blade  300  within the fiber-illuminated handle  400  in an operating position, in which the laryngoscope is ready-for-use. To place the fiber-illuminated blade  300  in the operating position, the blade fitting  330  is first attached to the hook-on fitting  410 . The blade fitting  330  is attached to the hook-on fitting  410  of the fiber-illuminated handle  400  by placing the hinge pin  418  of the hook-on fitting  410  within the hinge slot  334  of the blade fitting  330  and providing relative movement between the hinge pin  418  and the hinge slot  334  until the hinge pin  418  abuts against the semicircular bearing surface  335  of the hinge slot  334  and is locked therein by the hinge lock  336 . Relative rotational movement is provided between the fiber-illuminated blade  300  and the fiber-illuminated handle  400  such that the hinge slot  334  and the hinge pin  418  are rotated relative to one and other until the body  332  of the blade fitting  330  slides within the seat  419  of the hook-on fitting  410 . When the body  332  of the blade fitting  330  is fully received within the seat  419  of the hook-on fitting  410 , the first and second side locks  338   a ,  338   b  of the blade fitting  330  respectively engage with the first and second lock slots  416   a ,  416   b  of the hook-on fitting  410 . The fiber-illuminated blade  300  is thus locked within the fiber-illuminated handle  400  in the operating position. In the operating position, the light guide interface  339  of the blade fitting  330  is engaged with the optical pathway  412  of the hook-on fitting  410 , and the laryngoscope is ready-for-use. 
     Critical dimensions of conventional blades, conventional handles, fiber-illuminated blades, and fiber-illuminated handles conform to International Organization for Standardization (i.e., ISO)—International Standard 7376 for “Anesthetic and respiratory equipment—Laryngoscopes for tracheal intubation,” which provides general requirements for laryngoscopes used for intubation. Because of the fitting standardization provided by ISO Standard 7376, conventional blades of varying types and sizes are interchangeably connectable with conventional handles of varying sizes and shapes. Similarly, fiber-illuminated blades of varying types and sizes are interchangeably connectable with fiber-illuminated handles of varying types and sizes. 
     With known interchangeable laryngoscope blades and handles, conventional blades will not function with fiber-illuminated handles, since fiber-illuminated handles do not include electrical contacts to supply the lamp of the conventional blade with power from batteries disposed within the handle. Similarly, fiber-illuminated blades will not function with conventional handles, since conventional handles include neither the lamp nor the optical pathway for interfacing with the light guide of the fiber-illuminated blade. 
     Accordingly, the dimensions of the blade fittings and hook-on fittings prescribed by ISO Standard 7376 intentionally limits the mechanical interchangeability of laryngoscope blades and handles to prevent handle/blade engagement that will not properly function (e.g., that will not produce light to illuminate the larynx). That is, blade fittings of conventional blades dimensioned to ISO Standard 7376 will not engage with hook-on fittings of fiber-illuminated handles dimensioned to ISO Standard 7376 for fiber-illuminated handles, and blade fittings of fiber-illuminated blades dimensioned to ISO Standard 7376 will not engage with hook-on fittings of conventional handles dimensioned to ISO Standard 7376 for conventional handles. For example, the thickness T C  of the body  132  of the conventional blade  100  is less than the thickness T F  of the body  332  of the fiber-illuminated blade  300 , and the width W C  of the seat  219  of the conventional handle  200  is less than the width W F  of the seat  419  of the fiber-illuminated handle  400 . Due to this configuration, engagement between the blade fitting  330  of the fiber-illuminated blade  300  and the hook-on fitting  210  of the conventional handle  200  is prevented because the thickness T F  of the body  332  of the fiber-illuminated blade  300  is thicker than the width W C  of the seat  219  of the conventional handle  200 . That is, the body  332  of the fiber-illuminated blade  300  is too thick to fit within the seat  219  of the conventional handle  200 . 
     Further, the diameter of the semicircular bearing surface  135  of the hinge slot  134  of the conventional blade  100  is smaller than the diameter of the semicircular bearing surface  335  of the hinge slot  334  of the fiber-illuminated blade  300 , and the diameter d C  of the hinge pin  218  of the conventional handle  200  is smaller than the diameter d F  of the hinge pin  418  of the fiber-illuminated handle  400 . Due to this configuration, engagement between the blade fitting  130  of the conventional blade  100  and the hook-on fitting  410  of the fiber-illuminated handle  400  is prevented because the diameter d F  of the hinge pin  418  of the fiber-illuminated handle  400  is too large to fit properly within the semicircular bearing surface  135  of the hinge slot  134  of the conventional blade  100 . 
     The limited interchangeability of laryngoscope blades and handles renders obsolete otherwise useful laryngoscope handles that do not interface with incompatible laryngoscope blades. The limited interchangeability can limit a users&#39; choice of laryngoscope blades. For example, if an institution (e.g., a hospital) makes a significant investment in fiber-illuminated laryngoscope blades and handles, it is costly to later switch to conventional blades because doing so would render obsolete the stock of otherwise useful fiber-illuminated handles that are not connectable with the conventional blades. 
     SUMMARY 
     The present inventors recognize that there exists a need for a universal laryngoscope blade that addresses the shortcomings of current laryngoscope blades. There exists a need for a universal laryngoscope blade that is interchangeably connectable to, and functional with, hook-on fittings of both conventional handles and fiber-illuminated handles that are dimensioned according to ISO Standard 7376. 
     According to one aspect of the invention, a universal laryngoscope blade comprises a blade body shaped to provide a direct view of a larynx. The blade body includes a first end and a second end. The second end is configured for insertion into the larynx. The universal laryngoscope blade further comprises a viewer connected to the blade body. The viewer being configured to function independently from each of a conventional handle and a fiber-illuminated handle. The universal laryngoscope blade further comprises a blade fitting disposed at the first end of the blade body. The blade fitting is removably connectable to, one at a time, each of a hook-on fitting of the conventional handle and a hook-on fitting of the fiber-illuminated handle. The hook-on fitting of the conventional handle having at least one physical dimension that is different from at least one physical dimension of the hook-on fitting of the fiber-illuminated handle. 
     According to another aspect of the invention, the universal laryngoscope blade may further comprise a power source configured to be in electrical communication with the viewer to supply power to the viewer when the laryngoscope blade is engaged to one of the conventional handle and the fiber-illuminated handle in an operating position. The blade fitting may include a first electrical contact in electrical communication with the power source and a second electrical contact in electrical communication with the viewer, wherein the first electrical contact is configured to be in electrical communication with the second electrical contact via a hinge pin of one of the conventional handle and the fiber-illuminated handle when the laryngoscope blade is in the operating position. The first electrical contact may be in electrical communication with the power source via a first electrical wire, and the second electrical contact may be in electrical communication with the viewer via a second electrical wire. 
     According to another aspect of the invention, a method of engaging universal laryngoscope blades with a conventional handle and a fiber-illuminated handle comprises providing a first universal laryngoscope blade of the universal laryngoscope blades. The first universal laryngoscope blade comprises a blade body including a first end and a second end. The first universal laryngoscope blade further comprises a viewer connected to the blade body. The viewer is configured to function independently from each of the conventional handle and the fiber-illuminated handle. The first universal laryngoscope blade further comprises a blade fitting disposed at the first end of the blade body. The method further comprises providing a second universal laryngoscope blade of the universal laryngoscope blades. The second universal laryngoscope blade comprises a blade body including a first end and a second end. The second universal laryngoscope blade further comprises a viewer connected to the blade body. The viewer is configured to function independently from each of the conventional handle and the fiber-illuminated handle. The second universal laryngoscope blade further comprises a blade fitting disposed at the first end of the blade body. The blade fitting of the first universal laryngoscope blade and the blade fitting of the second universal laryngoscope blade being identically dimensioned. The method further comprises providing the conventional handle. The conventional handle including a hook-on fitting comprising a seat having a width and a hinge pin having a diameter. The method further comprises providing the fiber-illuminated handle. The fiber-illuminated handle including a hook-on fitting comprising a seat having a width and a hinge pin having a diameter. The width of the seat of the fiber-illuminated handle is greater than the width of the seat of the conventional handle, the diameter of the hinge pin of the fiber-illuminated handle is greater than the diameter of the hinge pin of the conventional handle. The method further comprises engaging the blade fitting of the first universal laryngoscope blade with the hook-on fitting of the conventional handle such that the first universal laryngoscope blade is provided in an operating position and ready-for-use. The method further comprises engaging the blade fitting of the second universal laryngoscope blade with the hook-on fitting of the fiber-illuminated handle such that the second universal laryngoscope blade is provided in an operating position and ready-for-use. 
     There are, of course, additional aspects of the various embodiments of the invention disclosed herein that will be described below and which will form the subject matter of the claims. In this respect, before explaining at least one aspect of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of aspects in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the Abstract, are for description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this invention is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order that the invention may be readily understood, aspects of the invention are illustrated by way of examples in the accompanying drawings; however, the subject matter is not limited to the disclosed aspects. 
         FIG. 1A  shows a side view of a known conventional blade. 
         FIG. 1B  shows a rear view of the known convention blade. 
         FIG. 1C  shows a magnified side view of the blade fitting of the known conventional blade. 
         FIG. 2A  shows a perspective view of a known conventional handle. 
         FIG. 2B  shows a top view of a hook-on fitting of the known conventional handle. 
         FIG. 2C  shows a cut-away side view of the hook-on fitting of the known conventional handle taken along section B-B of  FIG. 2B . 
         FIG. 3A  shows a side view of a known fiber-illuminated blade. 
         FIG. 3B  shows a rear view of the known fiber-illuminated blade. 
         FIG. 3C  shows a magnified side view of the blade fitting of the known fiber-illuminated blade. 
         FIG. 4A  shows a perspective view of a known fiber-illuminated handle. 
         FIG. 4B  shows a top view of the hook-on fitting of the known fiber-illuminated handle. 
         FIG. 4C  shows a cut-away side view of the hook-on fitting of the known fiber-illuminated handle taken along section A-A of  FIG. 4B . 
         FIG. 5A  shows a side view of an exemplary universal laryngoscope blade having at least one cable for direct connection to an external device in accordance with aspects of the invention. 
         FIG. 5B  shows a schematic representation of an exemplary embodiment of a viewer of the universal laryngoscope and of an external device in accordance with aspects of the invention. 
         FIG. 6A  shows a side view of another exemplary universal laryngoscope blade embodiment having a viewer without any direct connection to an external device in accordance with aspects of the invention. 
         FIG. 6B  shows a schematic representation of another exemplary embodiment of the viewer of the universal laryngoscope and of the external device in accordance with aspects of the invention. 
         FIG. 7A  shows a magnified rear view of a blade fitting in accordance with aspects of the invention. 
         FIG. 7B  shows a magnified side view of the blade fitting in accordance with aspects of the invention. 
         FIG. 8A  shows a side view of the universal laryngoscope blade hooked-on to the hinge pin of the conventional handle in accordance with aspects of the invention. 
         FIG. 8B  shows a side view of the universal laryngoscope blade engaged with the conventional handle in the operating position in accordance with aspects of the invention. 
         FIG. 9A  shows a rear view of the universal laryngoscope blade engaged with the conventional handle in the operating position in accordance with aspects of the invention. 
         FIG. 9B  shows a magnified cross-sectional view of the engagement between blade fitting of the universal laryngoscope blade and the hook-on fitting of the conventional handle of  FIG. 9A  taken along section F-F. 
         FIG. 9C  shows a magnified cross-sectional view of the engagement between the blade fitting of the universal laryngoscope blade and the hook-on fitting of the conventional handle of  FIG. 9A  taken along section H-H. 
         FIG. 10A  shows a side view of the universal laryngoscope blade hooked-on to the hinge pin of the fiber-illuminated handle in accordance with aspects of the invention. 
         FIG. 10B  shows a side view of the universal laryngoscope blade engaged with the fiber-illuminated handle in the operating position in accordance with aspects of the invention. 
         FIG. 11A  shows a rear view of the universal laryngoscope blade engaged with the fiber-illuminated handle in the operating position in accordance with aspects of the invention. 
         FIG. 11B  shows a magnified cross-sectional view of the engagement between blade fitting of the universal laryngoscope blade and the hook-on fitting of the fiber-illuminated handle of  FIG. 11A  taken along section C-C. 
         FIG. 11C  shows a magnified cross-sectional view of the engagement between the blade fitting of the universal laryngoscope blade and the hook-on fitting of the fiber-illuminated handle of  FIG. 11A  taken along section J-J. 
         FIG. 12A  shows another implementation of a universal laryngoscope blade engaged to a conventional handle in an operating position. 
         FIG. 12B  shows a magnified view of  FIG. 12A  depicting the blade fitting of the universal laryngoscope blade engaged to a hook-on fitting of the conventional handle in an operating position. 
         FIG. 13  shows a process of using universal laryngoscope blades in accordance with aspects of the invention. 
     
    
    
     Features of the universal laryngoscope blade and associated methods according to aspects of the invention are described with reference to the drawings, in which like reference numerals refer to like parts throughout. 
     DETAILED DESCRIPTION 
       FIGS. 5A-7B  show exemplary views of universal laryngoscope blades in accordance with aspects of the invention.  FIG. 5A  shows a side view of an exemplary universal laryngoscope blade  500  having at least one cable  523  for direct connection to an external device  600 .  FIG. 5B  shows a schematic representation of an exemplary embodiment of the viewer  520  and the external device  600 .  FIG. 6A  shows a side view of another exemplary universal laryngoscope blade  500 ′ having a viewer  520 ′ without any direct connection to an external device  600 ′.  FIG. 6B  shows a schematic representation of another exemplary embodiment of the viewer  520 ′ and the external device  600 ′.  FIG. 7A  shows a magnified rear view of the blade fitting  530  in accordance with aspects of the invention.  FIG. 7B  shows a magnified side view of the blade fitting  530  in accordance with aspects of the invention. 
     The universal laryngoscope blade  500  includes a blade body  510 , a viewer  520 , and a blade fitting  530 . The universal laryngoscope blade  500  may be, entirely or partially, reusable or disposable. The blade body  510  may be shaped to provide a direct view of a larynx. The blade body  510  may be provided in any number of shapes and sizes depending, e.g., on the size of the patient, as would be readily understood by a person having ordinary skill in the art. The blade body  510  may include a first end and a second end. The second end may be inserted into the larynx of a patient. 
     The viewer  520  is connected to the blade body  510  and may illuminate the larynx when the second end of the blade body  510  is inserted therein. The viewer  520  may function (e.g., emit light, capture at least one image, etc.) independently from each of the conventional handle  200  and the fiber-illuminated handle  400 . That is, the viewer  520  does not rely on a laryngoscope handle for power, signal transmission, light emission, etc. The viewer  520  may include a housing  521 . The housing  521  may be provided within a chamber of the blade body  510 . Additionally, or alternatively, the housing  521  may be attached to an outer side of the blade body  510 . The housing  521  may include an opening  522 , positioned between the second end of the blade body  510  and the central portion of the blade body  510 . The opening  522  may open towards the second end of the blade body  510 . The opening  522  may be covered with a transparent window to seal an interior of the housing  521 . The transparent window may include a lens. The viewer  520  may include one or more cables  523 . The one or more cables  523  may define the housing  521 . The one or more cables  523  may extend from a rear of the blade body  510  for connection to an external device  600 . The external device  600  may be a device other than a laryngoscope handle. The external device  600  may include one or more of, e.g., a processor  602 , a display  604 , a power source  606 , a lamp, a transceiver  608  (the term “transceiver” as used herein includes one or more of each of a transmitter and a receiver combined into a single circuitry, or provided separately, capable of transmitting and receiving electronic signals), etc. The one or more cables  523  may be capable of transmitting light, electricity, data, etc., between the viewer  520  and the external device  600 . 
     The viewer  520  may include a lamp  524  that emits light from the opening  522  of the housing  521  in a direction towards the second end of the blade body  510  to illuminate the second end of the blade body  510  and/or the larynx. The lamp  524  may be provided within the housing  521 . The lamp  524  may be hermetically sealed within the housing  521 . Alternatively, the external device  600  may include the lamp  524 , and light may be directed through the one or more cables  523  to the opening  522  to illuminate the second end of the blade body  510  and/or the larynx. 
     The viewer  520  may include a camera  525  that may capture one or more images, from the perspective of the opening  522  of the housing  521 , of the second end of the blade body  510  and/or of the larynx. At least a portion of the camera  525 , and in embodiments the entire camera  525 , may be provided within the housing  521 . The camera  525  may be hermetically sealed within the housing  521 . Images collected by the camera  525  may be electronically transferred to the external device  600 . For example, the images may be electronically transferred via the one or more cables  523 . Additionally, or alternatively, the viewer  520  may include a transceiver  526  that may wirelessly transmit the images to the external device  600 . The transceiver  526  may receive control instructions from the processor  602 . The viewer  520  may also include a processor  527  that may control any of the lamp  524 , camera  525 , transceiver  526 , etc. The processor  527  may independently control the lamp  524 , camera  525 , and/or transceiver  526 , or may be used to implement control instructions transmitted from the external device  600  and received by the transceiver  526 . 
     The viewer  520  may include a power source  528  (e.g., a battery) that supplies power to the lamp  524 , camera  525 , transceiver  526 , processor  527 , etc. The power source  528  may be provided on the blade body  510 . The powers source  528  may be positioned within, or connected to, the housing  521 . Additionally, or alternatively, power may be supplied to the lamp  524  and/or the camera  525  from the external device  600  via the one or more cables  523 . 
     As shown in  FIGS. 5A and 5B , according to an embodiment of the invention, the viewer  520  may include the one more cables  523  that may supply light, electricity, and/or data. The viewer  520  may also include the lamp  524 , and optionally the camera  525 . The external device  600  may include a processor  602 , a display  604 , and a power source  606 . The one or more cables  523  provide electronic communication between, e.g., the external device  600 , and the lamp  524  and the camera  525 . For example, the one or more cables  523  transmit power to the lamp  524  and to the camera  525 . Images captured by the camera  525  are transmitted to the external device  600  via the one or more cables  523 . The processor  602  may control the lamp  524  and the camera  525  via signals sent through the at one or more cables  523 . 
     As shown in  FIGS. 6A and 6B , according to another embodiment of the invention, the viewer  520 ′ may be provided without any direct connection (i.e., cable link) with the external device  600 ′. For example, the viewer  520 ′ may include the lamp  524 , and optionally the camera  525 . The viewer  520 ′ also may include a power source  528  (e.g., a battery), a transceiver  526 , and a processor  527 . The external device  600 ′ may include a processor  602 , a display  604 , and a transceiver  608 . According to aspects invention, the viewer  520 ′ is fully functional (i.e., capable of producing/transmitting light/data, capable of capturing one or more images, etc.) without the need for the blade fitting  530  to interface with functional elements (e.g., the electrical contact  212  of the conventional handle  200  or the optical pathway  412  of the fiber-illuminated handle  400 ) on the conventional handle  200  or the fiber-illuminated handle  400 . In other words, the viewer  520 ′ is self-contained in that it may draw power form a source (e.g., an internal power source  528 ) other than the handle. 
     The blade fitting  530  is disposed at the first end of the blade body  510 . As discussed above, the hook-on fitting  210  of the conventional handle  200  has at least one physical dimension (e.g., the diameter d C  of the hinge pin  218 , the width We of the seat  219 , etc.) that is different from at least one physical dimension (e.g., the diameter d F  of the hinge pin  418 , the width W F  of the seat  419 ) of the hook on fitting of the fiber-illuminated blade  300 . Further, the hook-on fitting  210  of the conventional handle  200  is dimensioned to conform to ISO standard 7376 for conventional handles and the hook-on fitting  410  of the fiber-illuminated handle  400  is dimensioned to conform to ISO standard 7376 for fiber-illuminated handles. Nevertheless, the blade fitting  530  of the present invention is removably connectable to, and functional with, each of the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400 . The blade fitting  530  of the invention may also be adapted for removable connection to, and functionality with, hook-on fittings of other handles that differ from the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400  described herein. 
     The blade fitting  530  of the universal laryngoscope blade  500  includes a body  532 , a lock, and a hinge slot  534 . As shown in  FIG. 7A , the body  532  has a thickness T U . The thickness T U  of the body  532  of the universal laryngoscope blade  500  may be greater than the thickness T C  of the body of the conventional blade  100  but less than the thickness T F  of the body  332  of the fiber-illuminated blade  300 . For example, the thickness T U  may be between 12.74 and 12.84 mm, and more particularly may be 12.80 mm. According to aspects of the invention, because the thickness T U  of the body  532  of the universal laryngoscope blade  500  may be greater than the thickness T C  of the body  132  of the conventional blade  100  but less than the thickness T F  of the body  332  of the fiber-illuminated blade  300 , the body  532  of the universal laryngoscope blade  500  may be small enough to be received within the seat  219  of the conventional handle  200  while large enough to limit excessive play (wobbling) when received within the seat  419  of the fiber-illuminated handle  400 . That is, the body  532  of the universal laryngoscope blade  500  may be accommodated within, one at a time, the seat  219  of the conventional handle  200  and the fiber-illuminated handle  400 , improving the universality of blade fitting  530  of the universal laryngoscope blade  500 . A bottom of the body  532  may not include (i.e., may be free of) functional elements (e.g., electrical contacts, light guides, etc.) that would otherwise protrude from the body  532 . By not including functional elements on the body  532  of the blade fitting  530 , the bottom of the body  532  of the blade fitting  530  may not interfere with functional elements (e.g., electrical contacts, optical pathways, etc.) provided on the hook-on fittings of conventional handles and/or fiber-illuminated handles when connected thereto. Alternatively, the bottom of the body  532  may be equipped with a switch that activates the viewer  520  when the universal laryngoscope blade  500  is engaged with the conventional handle  200 /the fiber-illuminated handle  400  in the operating position. 
     The lock may include a hinge lock  536  disposed within a top surface of the hinge slot  534 . In embodiments, the hinge lock  536  may be disposed within a bottom surface of the hinge slot  534 . The lock may also include at least one side lock provided on at least one side of the body  532 . As is shown in  FIG. 7A , the at least one side lock may include first and second side locks  538   a ,  538   b  respectively provided on opposite sides of the body  532 . A center point of the second side lock  538   b  is indicted at the intersection of side lock crosshairs, as shown in  FIG. 7B . The hinge lock  536 , the first side lock  538   a , and/or the second side lock  538   b  may be detent mechanisms. The hinge slot  534  may extend into the body  532  at an angle from a front of the body  532  towards a central region of the body  532  and may terminate at a bearing surface  535 . The bearing surface  535  has semicircular shape having a diameter and a virtual center point, indicated by the intersection of hinge slot  534  crosshairs shown in  FIG. 7B , about which the bearing surface  535  forms the semicircular shape. The diameter of the semicircular bearing surface  535  of the hinge slot  534 , and a width of the hinge slot  534  in general, are dimensioned to accommodate, one at a time, the hinge pin  218  of the conventional handle  200  and the hinge pin  418  of the fiber-illuminated handle  400  such that the respective hinge pin is received within and abuts against the semicircular bearing surface  535 . That is, the hinge slot  534  is dimensioned to receive in abutment with the semicircular bearing surface  535 , one at a time, the hinge pin  218  of the hook-on fitting  210  of the conventional handle  200  and the hinge pin  418  of hook-on fitting  410  of the fiber-illuminated handle  400 . For example, the diameter of the semicircular bearing surface  535  of the hinge slot  534 , and a narrowest width of the hinge slot  534  in general, are each at least greater than 4.58 mm. 
     As shown in  FIG. 7B , a center of the hinge lock  536  is spaced forwardly from the virtual center of the semicircular bearing surface  535  by a horizontal distance H UHL . The horizontal distance H UHL  that the hinge lock  536  of the universal laryngoscope blade  500  is spaced forwardly from the virtual center of the semicircular bearing surface  535  of the universal laryngoscope blade  500  is less than the horizontal distance H FHL  that the hinge lock  336  of the fiber-illuminated blade  300  is spaced forwardly from the virtual center of the semicircular bearing surface  335  of the fiber-illuminated blade  300 . For example, the horizontal distance HURL that the hinge lock  536  of the universal laryngoscope blade  500  is spaced forwardly from the virtual center of the semicircular bearing surface  535  of the universal laryngoscope blade  500  may be between 0.86 and 0.90 mm, and more particularly may be 0.88 mm. By locating the hinge lock  536  the horizontal distance H UHL  forwardly from the virtual center of the semicircular bearing surface  535 , the hinge lock  536  may securely hold, one at a time, the hinge pin  218  of the conventional handle  200  and the hinge pin  418  of the fiber-illuminated handle  400  within the hinge slot  534  of the blade fitting  530 . That is, the hinge slot  534  and the hinge lock  536  of the universal laryngoscope blade  500  may accommodate, one at a time, the hinge pin  218  of the conventional handle  200 , and the larger hinge pin  418  of the fiber-illuminated handle  400 , improving the universality of the blade fitting  530  of the universal laryngoscope blade  500 . 
     The center point of the second side lock  538   b  may be spaced from the virtual center point of the semicircular bearing surface  535  by a distance having a horizontal distance component D UL_h , and a vertical distance component D UL_v . The center point of the second side lock  538   b  may be spaced rearwardly from the virtual center point of the semicircular bearing surface  535  by the horizontal distance component D UL_h , and may be spaced below the virtual center point of the bearing surface  535  by the vertical distance component D UL_v . A center point of the first side lock  538   a  may be provided at a corresponding position at the other side surface of the body  532  with respect to the virtual center point of the semicircular bearing surface  535  such that the first and second side locks  538   a ,  538   b  are spaced the same distance from the virtual center point of the semicircular bearing surface  535 . 
     The horizontal distance component D UL_h , and the vertical distance component D UL_v  may be set such that the side lock (i.e., the first side lock  538   a  or the second side lock  538   b ) may be accommodated within a respective lock slot of the conventional handle  200  when the universal laryngoscope blade  500  is engaged with the hook-on fitting  210  of the conventional handle  200  in an operating position, in which the laryngoscope is ready-for-use. The horizontal distance component D UL_h , and the vertical distance component D UL_v  may be set such that the side lock (i.e., the first side lock  538   a  or the second side lock  538   b ) may also be accommodated within a respective lock slot of the fiber-illuminated handle  400  when the universal laryngoscope blade  500  is engaged with the hook-on fitting  410  of the fiber-illuminated handle  400  in the operating position. For example, the horizontal distance component D UL_h  may be of a magnitude greater than the horizontal distance component D CL_h  of the blade fitting  130  of the conventional blade  100  and less than the horizontal distance component D FLh  of the blade fitting  330  of the fiber-illuminated blade  300 . The horizontal distance component D UL_h  may be 13.0 mm. The vertical distance component D UL_v  may be 0.8 mm. 
     As a result of the above-described features and dimensions (e.g., the thickness T U  of the body  532 , the width of the hinge slot  534 , the diameter of the semicircular bearing surface  535  of the hinge slot  534 , the horizontal distance H UHL , the horizontal distance component D UL_h , the vertical distance component D UL_v , etc.), the blade fitting  530  of the universal laryngoscope blade  500  may engage with, one at a time, both the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400 . Further, and as discussed above, the viewer  520  (or the viewer  520 ′) is fully functional (i.e., capable of producing/transmitting light/data, capable of capturing one or more images, etc.) without the need for the blade fitting  530  to interface with functional elements (e.g., the electrical contact  212  of the conventional handle  200  or the optical pathway  412  of the fiber-illuminated handle  400 ) on the conventional handle  200  or the fiber-illuminated handle  400 . Accordingly, the universal laryngoscope blade  500  may be attached to, and fully functional with, each of the conventional handle  200  and the fiber-illuminated handle  400  that are dimensioned to conform to the requirements of ISO Standard 7376. This may allow a user to remove handle compatibility from laryngoscope blade purchasing decisions to leverage initial investments in otherwise useful conventional handles and/or fiber-illuminated handles. Universal laryngoscope blades may also reap the benefits of economies of scale, since the universal laryngoscope blades may be produced in greater numbers due to the compatibility with both existing conventional handles and fiber-illuminated handles. 
       FIGS. 8A-9C  depict engagement of the universal laryngoscope blade  500  and the conventional handle  200 .  FIG. 8A  shows a side view of the universal laryngoscope blade  500  hooked-on to the hinge pin  218  of the conventional handle  200 .  FIG. 8B  shows a side view of the universal laryngoscope blade  500  engaged with the conventional handle  200  in the operating position.  FIG. 9A  shows a rear view of the universal laryngoscope blade  500  engaged with the conventional handle  200  in the operating position.  FIG. 9B  shows a magnified cross-sectional view of the engagement between blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  210  of the conventional handle  200  of  FIG. 9A  taken along section F-F.  FIG. 9C  shows a magnified cross-sectional view of the engagement between the blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  210  of the conventional handle  200  of  FIG. 9A  taken along section H-H. 
     The blade fitting  530  of the universal laryngoscope blade  500  is configured to engage with the hook-on fitting  210  of the conventional handle  200  to lock the universal laryngoscope blade  500  within the seat  219  of the conventional handle  200  in an operating position, in which the laryngoscope is ready-for-use. As shown in  FIG. 8A , to place the universal laryngoscope blade  500  in the operating position, the blade fitting  530  is first attached to the hook-on fitting  210 . The blade fitting  530  is attached to the hook-on fitting  210  of the conventional handle  200  by placing the hinge pin  218  of the hook-on fitting  210  within the hinge slot  534  of the blade fitting  530  and providing relative movement between the hinge pin  218  and the hinge slot  534  until the hinge pin  218  abuts against the semicircular bearing surface  535  of the hinge slot  534  and is locked therein by the hinge lock  536 .  FIG. 9B  shows the hinge lock  536  locking the hinge pin  218  of the conventional handle  200  within the hinge slot  534  of the universal laryngoscope blade  500  in the operating position. Relative rotational movement is provided between the universal laryngoscope blade  500  and the conventional handle  200  such that the hinge slot  534  and the hinge pin  218  are rotated relative to one and other until the body  532  of the blade fitting  530  slides within the seat  219  of the hook-on fitting  210 , as shown in  FIGS. 8B-9C . After the body  532  of the blade fitting  530  is fully received within the seat  219  of the hook-on fitting  210 , the first and second side locks  538   a ,  538   b  of the blade fitting  530  respectively engage with the first and second lock slots  216   a ,  216   b  of the hook-on fitting  210 , as shown in  FIG. 9C . With the side locks engaged with the respective lock slots and the hinge lock  536  engaged with the hinge pin  218 , the body  532  of the universal laryngoscope blade  500  is locked within the seat  219  of the conventional handle  200  in the operating position, and the laryngoscope is ready-for-use. The one or more cables  523  of the universal laryngoscope blade  500  may be connected to the external device  600  at any time prior to use. 
     Although  FIGS. 8A-9C  depict engagement between the universal laryngoscope blade  500  having one or more cables  523  and the conventional handle  200 , the invention also includes engagement between the universal laryngoscope blade  500  having the viewer  520 ′ without any direct connection (i.e., cable link) with the external device  600  and the conventional handle  200 . That is, the mechanical engagement between the blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  210  of the conventional handle  200  is the same regardless of the type of viewer employed by the universal laryngoscope blade  500 . Each universal laryngoscope blade  500  is self-contained in that the universal laryngoscope blade  500  does not require power or light from the conventional handle  200  (although in some embodiments power or light may be provided by an external device  600  other than the conventional handle  200 ). 
       FIGS. 10A-11C  depict engagement of the universal laryngoscope blade  500  and the fiber-illuminated handle  400 .  FIG. 10A  shows a side view of the universal laryngoscope blade  500  hooked-on to the hinge pin  418  of the fiber-illuminated handle  400 .  FIG. 10B  shows a side view of the universal laryngoscope blade  500  engaged with the fiber-illuminated handle  400  in the operating position.  FIG. 11A  shows a rear view of the universal laryngoscope blade  500  engaged with the fiber-illuminated handle  400  in the operating position.  FIG. 11B  shows a magnified cross-sectional view of the engagement between blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  410  of the fiber-illuminated handle  400  of  FIG. 11A  taken along section C-C.  FIG. 11C  shows a magnified cross-sectional view of the engagement between the blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  410  of the fiber-illuminated handle  400  of  FIG. 11A  taken along section J-J. 
     The blade fitting  530  of the universal laryngoscope blade  500  is also configured to engage with the hook-on fitting  410  of the fiber-illuminated handle  400  to lock the universal laryngoscope blade  500  within the seat  419  of the fiber-illuminated handle  400  in an operating position, in which the laryngoscope is ready-for-use. As shown in  FIG. 10A , to place the universal laryngoscope blade  500  in the operating position, the blade fitting  530  is first attached to the hook-on fitting  410 . The blade fitting  530  is attached to the hook-on fitting  410  of the fiber-illuminated handle  400  by placing the hinge pin  418  of the hook-on fitting  410  within the hinge slot  534  of the blade fitting  530  and providing relative movement between the hinge pin  418  and the hinge slot  534  until the hinge pin  418  abuts against the semicircular bearing surface  535  of the hinge slot  534  and is locked therein by the hinge lock  536 .  FIG. 11B  shows the hinge lock  536  locking the hinge pin  418  of the fiber-illuminated handle  400  within the hinge slot  534  of the universal laryngoscope blade  500  in the operating position. Relative rotational movement is provided between the universal laryngoscope blade  500  and the fiber-illuminated handle  400  such that the hinge slot  534  and the hinge pin  418  are rotated relative to one and other until the body  532  of the blade fitting  530  slides within the seat  419  of the hook-on fitting  410 , as shown in  FIGS. 10B-11C . After the body  532  of the blade fitting  530  is fully received within the seat  419  of the hook-on fitting  410 , the first and second side locks  538   a ,  538   b  of the blade fitting  530  respectively engage with the first and second lock slots  416   a ,  416   b  of the hook-on fitting  410 , as shown in  FIG. 11C . With the side locks engaged with the respective lock slots and the hinge lock  536  engaged with the hinge pin  418 , the body  532  of the universal laryngoscope blade  500  is locked within the seat  419  of the fiber-illuminated handle  400  in the operating position, and the laryngoscope is ready-for-use. The one or more cables  523  of the universal laryngoscope blade  500  may be connected to the external device  600  at any time prior to use. 
     Although  FIGS. 10A-11C  depict engagement between the universal laryngoscope blade  500  having one or more cables  523  and the fiber-illuminated handle  400 , the invention also includes engagement between the universal laryngoscope blade  500  having the viewer  520 ′ without any direct connection (i.e., cable link) with the external device  600  and the fiber-illuminated handle  400 . That is, the mechanical engagement between the blade fitting  530  of the universal laryngoscope blade  500  and the hook-on fitting  410  of the fiber-illuminated handle  400  is the same regardless of the type of viewer employed by the universal laryngoscope blade  500 . Each universal laryngoscope blade  500  is self-contained in that the blade does not require power or light from the fiber-illuminated handle  400  (although in some embodiments power or light may be provided by an external device  600  other than the fiber-illuminated handle  400 ). 
       FIGS. 12A-12B  show exemplary views of another implementation of a universal laryngoscope blade  500 ″ in accordance with aspects of the present disclosure. The universal laryngoscope blade  500 ″ includes a blade body  510 ″, a viewer  520 ″, a power source  528 ″, and a blade fitting  530 ″. The universal laryngoscope blade  500 ″ may be, entirely or partially, reusable or disposable. The blade body  510 ″ may be the same as the blade body  510  previously discussed in detail above with regards to the other universal laryngoscope blade implementations. For instance, the blade body  510 ″ may be shaped to provide a direct view of a larynx. The blade body  510 ″ may be provided in any number of shapes and sizes depending, e.g., on the size of the patient. The blade body  510 ″ may include a first end and a second end, the power source  528 ″ disposed at the first end, and the second end operable for insertion into the larynx of a patient. 
     For illustrations purposes,  FIG. 12A  depicts engagement of the universal laryngoscope blade  500 ″ with the conventional handle  200 . In particular, a side view of the universal laryngoscope blade  500 ″ hooked-on to the hinge pin  218  of the conventional handle  200  is illustrated, such that the universal laryngoscope blade  500 ″ is engaged with the conventional handle  200  in the operating position.  FIG. 12B  shows a magnified view of the engagement between blade fitting  530 ″ of the universal laryngoscope blade  500 ″ and the hook-on fitting  210  of the conventional handle  200 . 
     The viewer  520 ″ is connected to the blade body  510 ″ and is operable to illuminate the larynx when the second end of the blade body  510 ″ is inserted therein. The viewer  520 ″ is operable to function (e.g., emit light, capture at least one image, etc.) independently with each of the conventional handle  200  and the fiber-illuminated handle  400 . The viewer  520 ″ may include a lamp  524 ″, such as an LED, that emits light in a direction towards the second end of the blade body  510 ″ to illuminate the second end of the blade body  510 ″ and/or the larynx. Similar to the other implementations discussed above, the lamp  524 ″ may be provided within a housing. The viewer  520 ″ may include a camera that may capture one or more images, from the perspective of an opening of the housing, of the second end of the blade body  510 ″ and/or of the larynx. The viewer  520 ″ may include a power source  528 ″ (e.g., one or more batteries) that supplies power to the lamp  524 ″, camera, etc. The power source  528 ″ may be provided on the blade body  510 ″, such as the first end of the blade body. 
     The universal laryngoscope blade  500 ″ is configured to be removably connectable, one at a time, to each of the conventional handle  200  and the fiber-illuminated handle  400 . The blade fitting  530 ″ of the laryngoscope blade  500 ″ is disposed at the first end of the blade body  510 ″. The blade fitting  530 ″ is configured to be removably connectable, one at a time, to each of the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400 . Moreover, the blade fitting  530 ″ is removably connectable to and functional with, one at a time, each of the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400 . In other implementations, the blade fitting  530 ″ may also be adapted for removable connection to, and functionality with, hook-on fittings of other handles that differ from the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400  described herein. 
     The blade fitting  530 ″ of the universal laryngoscope blade  500 ″ includes a body  532 ″, a lock, and a hinge slot  534 ″. The body  532 ″ is similar to the body  532  shown in  FIG. 7A  and has a thickness T U . The thickness T U  of the body  532 ″ of the universal laryngoscope blade  500 ″ may be greater than the thickness T C  of the body of the conventional blade  100  but less than the thickness T F  of the body  332  of the fiber-illuminated blade  300 . For example, the thickness T U  may be between 12.74 and 12.84 mm, and more particularly may be 12.80 mm. According to aspects of the invention, because the thickness T U  of the body  532 ″ of the universal laryngoscope blade  500 ″ may be greater than the thickness T C  of the body  132  of the conventional blade  100  but less than the thickness T F  of the body  332  of the fiber-illuminated blade  300 , the body  532 ″ of the universal laryngoscope blade  500 ″ may be small enough to be received within the seat  219  of the conventional handle  200  while large enough to limit excessive play (wobbling) when received within the seat  419  of the fiber-illuminated handle  400 . That is, the body  532 ″ of the universal laryngoscope blade  500 ″ may be accommodated within, one at a time, the seat  219  of the conventional handle  200  and the fiber-illuminated handle  400 , improving the universality of blade fitting  530 ″ of the universal laryngoscope blade  500 ″. 
     The lock may include a hinge lock  536 ″ disposed within a top surface of the hinge slot  534 ″. In some implementations, the hinge lock  536 ″ may be disposed within a bottom surface of the hinge slot  534 ″. The lock may also include at least one side lock provided on at least one side of the body  532 ″. The at least one side lock may include first and second side locks respectively provided on opposite sides of the body  532 ″, similar to slide locks  538   a ,  538   b  previously described above. The hinge lock  536 ″ and the at least one side lock may be detent mechanisms. The hinge slot  534 ″ may extend into the body  532 ″ at an angle from a front of the body  532 ″ towards a central region of the body  532 ″ and may terminate at a bearing surface  535 ″. The bearing surface  535 ″ may have a semicircular shape having a diameter and a virtual center point about which the bearing surface  535 ″ forms the semicircular shape. The diameter of the semicircular bearing surface  535 ″ of the hinge slot  534 ″, and a width of the hinge slot  534 ″ in general, are dimensioned to accommodate, one at a time, the hinge pin  218  of the conventional handle  200  and the hinge pin  418  of the fiber-illuminated handle  400  such that the respective hinge pin is received within and abuts against the semicircular bearing surface  535 ″. That is, the hinge slot  534 ″ is dimensioned to receive in abutment with the semicircular bearing surface  535 ″, one at a time, the hinge pin  218  of the hook-on fitting  210  of the conventional handle  200  and the hinge pin  418  of hook-on fitting  410  of the fiber-illuminated handle  400 . For example, the diameter of the semicircular bearing surface  535 ″ of the hinge slot  534 ″, and a narrowest width of the hinge slot  534 ″ in general, are each at least greater than 4.58 mm. 
     A center of the hinge lock  536 ″ is spaced forwardly from the virtual center of the semicircular bearing surface  535 ″ by a horizontal distance H UHL . The horizontal distance H UHL  that the hinge lock  536 ″ of the universal laryngoscope blade  500 ″ is spaced forwardly from the virtual center of the semicircular bearing surface  535 ″ of the universal laryngoscope blade  500 ″ is less than the horizontal distance H FHL  that the hinge lock  336  of the fiber-illuminated blade  300  is spaced forwardly from the virtual center of the semicircular bearing surface  335  of the fiber-illuminated blade  300 . For example, the horizontal distance H UHL  that the hinge lock  536 ″ of the universal laryngoscope blade  500 ″ is spaced forwardly from the virtual center of the semicircular bearing surface  535 ″ of the universal laryngoscope blade  500 ″ may be between 0.86 and 0.90 mm, and more particularly may be 0.88 mm. By locating the hinge lock  536 ″ the horizontal distance H UHL  forwardly from the virtual center of the semicircular bearing surface  535 ″, the hinge lock  536 ″ may securely hold, one at a time, the hinge pin  218  of the conventional handle  200  and the hinge pin  418  of the fiber-illuminated handle  400  within the hinge slot  534 ″ of the blade fitting  530 ″. That is, the hinge slot  534 ″ and the hinge lock  536 ″ of the universal laryngoscope blade  500 ″ may accommodate, one at a time, the hinge pin  218  of the conventional handle  200 , and the larger hinge pin  418  of the fiber-illuminated handle  400 , improving the universality of the blade fitting  530 ″ of the universal laryngoscope blade  500 ″. 
     As a result of the above-described features and dimensions (e.g., the thickness T U  of the body  532 ″, the width of the hinge slot  534 ″, the diameter of the semicircular bearing surface  535 ″ of the hinge slot  534 ″, the horizontal distance H UHL , etc.), the blade fitting  530 ″ of the universal laryngoscope blade  500 ″ may engage with, one at a time, both the hook-on fitting  210  of the conventional handle  200  and the hook-on fitting  410  of the fiber-illuminated handle  400 . Accordingly, the universal laryngoscope blade  500 ″ may be attached to, and fully functional with, each of the conventional handle  200  and the fiber-illuminated handle  400  that are dimensioned to conform to the requirements of ISO Standard 7376. 
     An electrical contact may be provided on the bearing surface  535 ″ of the blade fitting  530 ″. The electrical contact may be in electrical communication with the power source  528 ″ (i.e., batteries) via one or more wires  512 ″ for supplying power to the electrical contact. The electrical contact is further configured to be in electrical communication with the hinge pin  218  of the hook-on fitting  210  when the laryngoscope blade  500 ″ is in the operating position. The hinge pin  218  is metal or another electrically conductive material. An electrical hinge contact  537 ″ may be disposed on a surface of the hinge slot  534 ″ and may be adjacent to the hinge lock  536 ″. The electrical hinge contact  537 ″ is also configured to be in electrical communication with the hinge pin  218  when the laryngoscope blade  500 ″ is in the operating position. The electrical hinge contact  537 ″ may further be in electrical communication with the viewer  520 ″ via one or more wires  514 ″ for supplying power to the viewer, such as to the lamp  524 ″, when the laryngoscope blade  500 ″ is engaged with the conventional handle  200  in the operating position. 
     Although the universal laryngoscope blade  500 ″ is shown attached to and fully functional with the conventional handle  200  for illustrations purposes, the universal laryngoscope blade  500 ″ is also attachable to and fully functional with the fiber-illuminated handle  400  as previously discussed above. Accordingly, power may be supplied from the power source  528 ″ to the lamp  524 ″ using the existing metal hinge pin  218  of the conventional handle  200  or the metal hinge pin  418  of the fiber-illuminated handle to complete the electrical circuit between the power source and the lamp, thus reducing manufacturing costs as it would be unnecessary to include additional components, such as a microswitch, into the blade. 
     In some implementations, the hinge lock  536 ″ may be metal or another electrically conductive material, and furthermore may be configured to be in electrical communication with both the hinge pin  218  and the electrical hinge contact  537 ″ when the laryngoscope blade  500 ″ is in the operating position. Thus, a bottom of the body  532 ″ may not include (i.e., may be free of) functional elements (e.g., electrical contacts, light guides, etc.) that would otherwise protrude from the body  532 ″. By not including functional elements on the body  532 ″ of the blade fitting  530 ″, the bottom of the body  532 ″ of the blade fitting  530 ″ may not interfere with functional elements (e.g., electrical contacts, optical pathways, etc.) provided on the hook-on fittings of conventional handles and/or fiber-illuminated handles when connected thereto. 
       FIG. 13  shows a process  1200  of using universal laryngoscope blades in accordance with aspects of the invention, including engaging universal laryngoscope blades with a conventional handle and a fiber-illuminated handle (e.g., the conventional handle  200  and the fiber-illuminated handle  400 ). The process  1200  may include, at a first step  1201 , providing a first universal laryngoscope blade. The first universal laryngoscope blade may be any of the universal laryngoscope blades discussed above in accordance with aspects of the invention. For example, the first universal laryngoscope blade may include a blade body shaped to provide a direct view of a larynx. The blade body may include a first end and a second end. The second end may be inserted into the larynx of a patient. The first universal laryngoscope blade may further include a viewer connected to the blade body. The viewer may function independently from each of the conventional handle and the fiber-illuminated handle. That is, the viewer is fully functional (i.e., able to emit light or capture images) without requiring power or light from the conventional handle or the fiber-illuminated handle. The first universal laryngoscope blade may further include a blade fitting disposed at the first end of the blade body. 
     The process  1200  may include, at a second step  1202 , providing a second universal laryngoscope blade. The second universal laryngoscope blade may be any of the universal laryngoscope blades discussed above in accordance with aspects of the invention. For example, the second universal laryngoscope blade may include a blade body shaped to provide a direct view of a larynx. The blade body may include a first end and a second end. The second end may be inserted into the larynx of a patient. The second universal laryngoscope blade may further include a viewer connected to the blade body. The viewer may function independently from each of the conventional handle and the fiber-illuminated handle. That is, the viewer is fully functional (i.e., able to emit light or capture images) without requiring power or light from the conventional handle or the fiber-illuminated handle. The second universal laryngoscope blade may further include a blade fitting disposed at the first end of the blade body. the blade fitting of the second universal laryngoscope blade being identically dimensioned with the blade fitting of the first universal laryngoscope blade. That is, the physical dimensions of each of the above described components of the blade fitting of the universal laryngoscope blade (e.g., the body, the lock, the hinge slot, etc.) may be identical so that the blade fitting of each of the first and second universal laryngoscope blades is the same. “Identically dimensioned,” as used herein, means machined to the same size, but includes normal variations resulting from manufacturing tolerances, which would be readily understood by persons having ordinary skill in the art. 
     The process  1200  may include, at a third step  1203 , providing the conventional handle, as discussed above. That is, providing the conventional handle including a hook-on fitting having a seat having a width and a hinge pin having a diameter. The dimensions of the hook-on fitting of the conventional handle may conform to dimensions prescribed for conventional handles in ISO standard 7376. 
     The process  1200  may include, at a forth step  1204 , providing the fiber-illuminated handle, as discussed above. That is, providing the fiber-illuminated handle including a hook-on fitting comprising a seat having a width and a hinge pin having a diameter. The dimensions of the hook-on fitting of the fiber-illuminated handle may conform to dimensions prescribed for fiber-illuminated handles for ISO standard 7376. As is clear from ISO standard 7376, the width of the seat of the fiber-illuminated handle is greater than the width of the seat of the conventional handle, and the diameter of the hinge pin of the fiber-illuminated handle is greater than the diameter of the hinge pin of the conventional handle. 
     The process  1200  may include, at a fifth step  1205 , engaging the blade fitting of the first universal laryngoscope blade with the hook-on fitting of the conventional handle such that the first universal laryngoscope blade is provided in an operating position and ready-for-use. An example of engaging the blade fitting of the first universal laryngoscope blade with the hook-on fitting of the conventional handle is shown, for example, in  FIGS. 8A-9C  and is discussed in greater detail above. 
     The process  1200  may include, at a sixth step  1206 , engaging the blade fitting of the second universal laryngoscope blade with the hook-on fitting of the fiber-illuminated handle such that the second universal laryngoscope blade is provided in an operating position and ready-for-use. An example of engaging the blade fitting of the second universal laryngoscope blade with the hook-on fitting of the fiber-illuminated handle is shown, for example, in  FIGS. 10A-11C  and is discussed in greater detail above. 
     Because the blade fittings of the first and second universal laryngoscope blades are identically dimensioned (including e.g., the thickness T U  of the body, the width of the hinge slot, the diameter of the semicircular bearing surface of the hinge slot, the horizontal distance H UHL , the horizontal distance component D UL_h , the vertical distance component D UL_v , etc.), the blade fitting of the universal laryngoscope blades may each engage with, one at a time, both the hook-on fitting of the conventional handle and the hook-on fitting of the fiber-illuminated handle. Further, and as discussed above, the viewers of each of the universal laryngoscope blades are fully functional (i.e., capable of producing/transmitting light/data, capable of capturing one or more images, etc.) without the need for the blade fitting to interface with functional elements (e.g., the electrical contact of the conventional handle or the optical pathway of the fiber-illuminated handle) on the conventional handle or the fiber-illuminated handle. Accordingly, the universal laryngoscope blades may be attached to, and fully functional with, each of the conventional handle and the fiber-illuminated handle that conform to the requirements of ISO Standard 7376. This allows a user to remove handle compatibility from laryngoscope blade purchasing decisions to leverage initial investments in otherwise useful conventional handles and/or fiber-illuminated handles. Universal laryngoscope blades may also reap the benefits of economies of scale, since the universal laryngoscope blades may be produced in greater numbers due to the compatibility with both existing conventional handles and fiber-illuminated handles. 
     The many features and advantages of the universal laryngoscope blade described herein are apparent from the detailed specification, and thus, the claims cover all such features and advantages within the scope of this application. Further, numerous modifications and variations are possible. As such, it is not desired to limit the universal laryngoscope blade to the exact construction and operation described and illustrated and, accordingly, all suitable modifications and equivalents may fall within the scope of the claims.