Abstract:
Intubation laryngoscope having reusable and disposable blades, an illumination system, and an advantageous fastening appliance for connecting the blades to the laryngoscope handle.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to the intubation laryngoscopes having reusable and disposable blades, an illumination system, and an improved fastening appliance for connecting the blades to the laryngoscope handle. 
         [0003]    2. Prior Art 
         [0004]    The most widely spread design of intubation laryngoscope  100 , for example fabricated by Welch Allyn company (see enclosed  FIGS. 1 to 3 ), comprises a blade set, including four detachable blades of curvilinear Macintosh profile of various sizes designed for operations with children and adults. Each blade  101 , made of stainless steel, extends from a lower end of handle  104  in a distal direction and has blade distal end portion  102  designed to expose a tracheal entrance in order to insert an endotracheal tube therein, as well as blade proximal end portion  103  designed for detachable connection with laryngoscope handle  104  through blade holder  105 . The latter consists of two parts including upper holder part  106  immovably affixed to a lower end of handle  104 , and lower holder part  107  immovably fastened to blade proximal end portion  103  and movably fastened to upper holder part  106  by a holder fastening means. The latter include: two lateral walls  108 ,  109  of upper holder part  106  spaced some distance apart, protruding downward and arranged in parallel with a plane passing through the distal direction of the detachable blade extension ( FIG. 3 ) and a longitudinal axis of the handle; axle  110  mounted between lateral walls  108 ,  109  at a distal edge of upper holder part  106 ; insertion portion  111  of lower holder part  107  to be inserted between lateral walls  108 ,  109  with a small gap; hook  112  in the form of straight-line groove  113 , opened from a distal lateral side, disposed at a distal edge of insertion portion  111  and adapted for putting on axle  110  to envelop the axle from upper, lower and proximal sides with a capability of rotating lower holder part  107  along with blade  101  around axle  110  clockwise in order to set lower holder part  107  into an operation position shown in  FIG. 3  and allowing an intubation execution, or counter-clockwise in order to set lower holder part  107  into inoperative position, specifically to detach blade  101  along with lower holder part  107  from handle  104 . 
         [0005]    The holder fastening means also comprise a holder locking means preventing lower holder part  107  from spontaneous dislocation relative to upper holder part  106  in the operation position and, specifically, including a detent means preventing lower holder part  107  from spontaneous rotation around axle  110  in the operation position. The detent means comprise detent recess  114  located on an inner side of lateral wall  108 , and ball springy detent  115  mounted at insertion portion  111  oppositely to the hook disposition and having a ball adapted to enter detent recess  114  in the operation position and to come out from the detent recess in the inoperative position. The holder locking means also include a keeping means made as ball keeper  116  mounted in a lower wall of hook groove  113 , interacting with axle  110  and preventing lower holder part  107  from spontaneous dislocating relative to upper holder part  107  in the operation position and from spontaneous falling out of upper holder part  106  in the inoperative position. Mounting the ball keeper  116  is implemented through upper window  119 , which substantially weakens hook  112 . 
         [0006]    Laryngoscope  100  is provided with an illumination means designed to illuminate a zone of endotracheal tube insertion in patient&#39;s mouth and comprising batteries housed in the handle, a light source disposed in upper holder part  106 , light guide  117  located in a unit of lower holder part  107  and blade  101 , and a switch for turning on/of an illumination light. The latter includes movable element  118  disposed on upper holder part  106  between lateral walls  108 ,  109  at some distance from axle  110 , protruding downward from an inner upper surface of upper holder part  106 , and interacting with lower holder part  107  so that, in the operation position of the lower holder part, movable element  118  is dislocated upward by pressure of lower holder part  107  thereby turning on the illumination light. In the inoperative position the movable element is released by the lower holder part that leads to returning downward the movable element and thereby to turning off the illumination light. 
         [0007]    In version embodiment of intubation laryngoscopes, fabricated by company “Penlon”, the blade is made of plastic and the locking means are made as latches including plastic projections located on resilient legs arranged on the holder lower part. 
         [0008]    In another version embodiment, fabricated by several companies, specifically by “Ismel Ltd”, the illumination means include a light source disposed on the blade and connected with the batteries housed in the handle through the switch identical to described above. 
         [0009]    There is a host of patents, devoted to the solutions of various laryngoscope problems, wherein the laryngoscopes identical to above are presented, for example, U.S. Pat. No. 4,579,108, U.S. Pat. No. 6,454,704, U.S. Pat. No. 5,003,962, U.S. Pat. No. 5,800,344, U.S. Pat. No. 5,575,758, US 2004/0242967A1, US 2007/0093693 A1. 
         [0010]    The disadvantage of the above intubation laryngoscope is its relatively high cost and complexity caused with the necessity to provide each blade of the blade set with its own lower holder part. 
         [0011]    Another disadvantage is the need for special ball keeper to prevent the lower holder part from the lateral dislocation in the operation position and from spontaneous falling out from the upper holder part in the inoperative position, resulting in the design complication, rise in price, and weakening the hook strength. 
         [0012]    Another disadvantage is the application restrictions of laryngoscope design, specifically, eliminating the capability of the updated blade using without the handle refinement. 
         [0013]    Another disadvantage is the load distribution characterized by excessive loading the hook resulting in insufficient hook strength in the version of blade and lower holder part made of plastic. 
         [0014]    Another disadvantage is the necessity for arrangement of parts of the illumination system, such as the light guide or the light source, in each blade, leading to increasing the price of the blades and the illumination system. 
       SUMMARY OF THE INVENTION 
       [0015]    The objective of the present invention is substantial decrease in price of laryngoscope due to the capability of using a common single lower holder part for each blade of the blade set. 
         [0016]    Another objective is decrease in price of laryngoscope as a result of the elimination of the ball keeper due to fulfilling the ball keeper functions by the other elements of the lower holder part. 
         [0017]    Another objective is substantial reducing the requirements for the strength of the lower holder part, specifically in the plastic embodiment, due to the redistribution of loading the elements of the lower holder part. 
         [0018]    Another objective is the extension of the laryngoscope applicability by updating only its lower holder part resulting in the capability of using the blade various designs. 
         [0019]    Another objective is simplification and decreasing in the price of the detachable blade as a result of eliminating the illumination system parts from the blade design. 
         [0020]    The above noted objectives are accomplished with an intubation laryngoscope comprising a handle and at least one detachable blade extending from a lower end of said handle in a distal direction and having a blade distal end portion designed to expose a tracheal entrance in order to insert an endothracheal tube therein and a blade proximal end portion. There is also a holder designed for fastening the blade proximal end portion to the handle lower end and including an upper holder part immovably affixed to a lower end of said handle, and a lower holder part movably fastened to the upper holder part and adapted for detachable connection with the blade proximal end portion. 
         [0021]    Such lower holder part is a novelty allowing using a common single lower holder part for each blade of the blade set, thereby providing decrease in price of laryngoscope in comparison with the known versions having the lower holder part on each blade of blade set. Moreover, there is a capability of the easy laryngoscope adaptation to operation with various blade kinds by changing only the single lower holder part. 
         [0022]    The offered lower holder part is detachably fastened to the upper holder part by a holder fastening means including: two lateral walls of the upper holder part spaced some distance apart and protruding downward; an axle mounted between the lateral walls at an edge of the upper holder part; an insertion portion of the lower holder part to be inserted between the lateral walls with a small gap; a hook disposed at an edge of the insertion portion of lower holder part and adapted to putting on the axle with a capability of rotating the lower holder part around the axle to set a needed position of the lower holder part relative to the upper holder part; a holder locking means preventing the lower holder part from spontaneous dislocation relative to the upper holder part in the operation position allowing the intubation execution. 
         [0023]    The intubation laryngoscope comprises an illumination means designed to illuminate the patient&#39;s mouth zone of the endotracheal tube insertion, and provided with a light source and a switch for turning on/off an illumination light. The switch includes a movable element disposed on the upper holder part between the lateral walls at some distance from the axle, protruding downward from an inner upper surface of the upper holder part, and interacting with the lower holder part. In the operation position of the lower holder part the movable element is dislocated upward by pressure of the lower holder part thereby turning on the illumination light. In the inoperative position the movable element is released by the lower holder part that leads to returning downward the movable element and thereby to turning off the illumination light. 
         [0024]    The mentioned hook is formed as a groove having a U-shaped upper portion directed downward with its open side so that inner walls of the U-shaped upper portion are disposed substantially in parallel with a longitudinal axis of the handle and interact with the axle thereby preventing the lower holder part from dislocating in a lateral directions relative to the upper holder part in the operation position. Such arrangement of the hook groove is novelty allowing the groove inner walls to fulfill the function of the ball keeper. As a result, the ball keeper and the upper window used for the ball keeper mounting may be eliminated that reduces the laryngoscope price and strengthens the hook. 
         [0025]    In the inoperative position of lower holder part, used for detaching the hook from the axle, an outer surface of the hook wall is projected some upward relative to a lower surface of the movable element in its released state, thereby preventing the lower holder part from spontaneous falling out of the upper holder part in the inoperative position, and providing for a need for dislocating the movable element upward in order to detach the lower holder part from the upper holder part as well as in order to put the hook on the axle. Such design of the hook is novelty allowing the hook to fulfill the part of the functions fulfilled by the ball keeper in the existing laryngoscope. 
         [0026]    The holder fastening means include a holder locking means preventing the lower holder part from spontaneous dislocation relative to the upper holder part in the operation position. The holder locking means comprises a detent means preventing the lower holder part from a spontaneous rotation around the axle in the operation position, including: a detent recess located on an inner side of at least one of the lateral walls; and a ball springy detent mounted at an insertion portion edge opposite to the edge, at which the hook is disposed, and having a ball adapted to enter the detent recess in the operation position and to come out from the detent recess in the inoperative position. 
         [0027]    According to the present invention, the intubation laryngoscope is provided with a blade fastening means designed for detachable fastening the detachable blade to the lower holder part, and a blade locking means preventing the detachable blade from disengagement from the lower holder part in the operation position. The blade fastening means include: a blade socket located at the blade proximal end portion and opened from a proximal side of the detachable blade; and a fastening protrusion of the lower holder part protruding distally of the insertion portion of lower holder part, adapted to inserting into the blade socket and having external configuration corresponding to an inner configuration of the blade socket to maximally restrict a displacement of the detachable blade relative to the lower holder part after inserting the fastening protrusion into the blade socket. 
         [0028]    After full inserting the fastening protrusion into the blade socket in the inoperative position and subsequent setting the operation position of the lower holder part, the blade proximal portion is extended some proximally of a proximal edge of the upper holder part and comprises at least one lug, which is located on a proximal end of the blade proximal portion proximally of a proximal edge of the upper holder part so that an extreme lug distal surface contacts with an extreme proximal surface of the upper holder part thereby fulfilling a function of the blade locking means preventing the detachable blade from displacement distally of the lower holder part in the operation position. As long as the holder locking means, specifically the ball springy detent, hold the lower holder part in the operation position, the blade locking means in the form of the lug hold the detachable blade from disengagement from the lower holder part. 
         [0029]    There is also an additional blade locking means designed for preventing the detachable blade from spontaneous detachment from the lower holder part in the inoperative position and providing for a need for some operator&#39;s effort to disconnect the detachable blade and the lower holder part in the inoperative position. The additional blade locking means is made as a latch appliance including a resilient leg located on the blade proximal portion and having a latch opening, as well as a latch projection located on the lower holder part and adapted to entering the latch opening, when the fastening protrusion of lower holder part is inserted into said blade socket. 
         [0030]    The offered blade locking means in the form of the lug is novelty, which along with the mentioned blade fastening means and additional blade locking means allow obtaining the extreme simple and inexpensive blade design in the form of a single plastic piece. 
         [0031]    In version embodiments, the axle is disposed at an acute angle up to a zero angle to a plane passing through a longitudinal axis of said handle and the distal direction of detachable blade extension, and internal surfaces of the two lateral walls are disposed at an acute angle up to a right angle to the mentioned plane. Specifically in one version, the angle of axle disposition is zero and the disposition angle of the internal surfaces of two lateral walls approximately is right. The use of these angles is novelty allowing maximal reduction of the requirements for the strength of the lower holder part, specifically for the strength of the hook, due to the redistribution of loading the elements of the lower holder part. As a result, the capability of lower holder part manufacture of plastic, having sufficient strength, arises. In another version, the angle of axle disposition is equal to 45° and the disposition angle of the internal surfaces of two lateral walls also is equal to 45°. This version is characterized with some decreased hook strength but has improved the transversal fixation of the lower holder part relative to the upper holder part in the operative position. 
         [0032]    The offered lower holder part allows the following versions of the illumination means:
   1) the illumination means include batteries located within the handle, the light source located in the upper holder part, and a light guide, which in the operation position is located in the lower holder part between the light source and a distal face of the lower holder part;   2) the illumination means include batteries located within the handle and electrically connected with the movable element, the light source located in the distal end of the lower holder part, and a lead wire located in the lower holder part and connecting the light source with an electric contact, which is disposed on an upper surface of the insertion portion of lower holder part and in the operation position contacting with the movable element;   3) the illumination means, including batteries and the light source, fully disposed in the lower holder part. The latter version is novelty, allowing considerable simplifying and price reducing the design of the handle and the upper holder part.   
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]      FIGS. 1 to 3  show the intubation laryngoscopes and their components of Prior Art, wherein: 
           [0037]      FIG. 1  shows a holder lower part immovably affixed to a detachable blade. 
           [0038]      FIG. 2  shows a holder upper part immovably affixed to a laryngoscope handle. 
           [0039]      FIG. 3  shows the laryngoscope assembly of company “Welch Allyn”. 
           [0040]    The drawings presented in the following relate to the present invention. 
           [0041]      FIGS. 4 to 8  show a version of an offered laryngoscope having a light source arranged in an upper holder part, as well as a hook of a lower holder part enveloping an axle of the upper holder part from above, from below and from a proximal side in an operation position, wherein: 
           [0042]      FIG. 4  shows a subassembly of the holder upper part immovably affixed to a laryngoscope handle and including the light source. 
           [0043]      FIG. 5  shows a subassembly of the lower holder part including a hook and a light guide, to be movably affixed to the holder upper part, and adapted to detachable connection with a laryngoscope blade. 
           [0044]      FIG. 6  shows the detachable blade depleted of any components of illumination means. 
           [0045]      FIG. 7  shows an external view of a laryngoscope assembly. 
           [0046]      FIG. 8  shows a cross-sectional view of the offered laryngoscope. 
           [0047]      FIGS. 9 to 17  show another version of the offered laryngoscope having a light source arranged in an upper holder part, as well as a hook of a lower holder part enveloping an axle of the upper holder part from above, from a distal side and from a proximal side in an operation position, wherein: 
           [0048]      FIG. 9  shows a subassembly of the lower holder part including the light guide and the hook. 
           [0049]      FIG. 10  shows a subassembly of the upper holder part comprising the light source. 
           [0050]      FIG. 11  shows the detachable blade. 
           [0051]      FIG. 12  shows an external view of a laryngoscope assembly. 
           [0052]      FIG. 13  shows a cross-sectional view of the offered laryngoscope in an operation position. 
           [0053]      FIG. 14  shows a cross-sectional view of the offered laryngoscope in an inoperative position. 
           [0054]      FIGS. 15 to 17  show three stages of attaching the detachable blade to a holder. 
           [0055]      FIGS. 18 to 32  show another version of an offered laryngoscope having a light source arranged in a holder lower part, as well as a hook of a lower holder part enveloping an axle of the upper holder part from above, from a distal side and from a proximal side in an operation position, wherein: 
           [0056]      FIG. 18  shows a detachable blade. 
           [0057]      FIG. 19  shows a subassembly of the upper holder part adapted for transmitting electrical energy from batteries housed in a handle to the light source. 
           [0058]      FIG. 20  shows a subassembly of the lower holder part. 
           [0059]      FIG. 21  shows an external view of a laryngoscope assembly. 
           [0060]      FIG. 22  shows an external view of an illuminating insertion appliance including components of an electrical circuit of the laryngoscope illumination means. 
           [0061]      FIG. 23  shows a ball springy detent. 
           [0062]      FIG. 24  shows a cross-sectional view of the illuminating insertion appliance. 
           [0063]      FIG. 25  shows the holder lower part. 
           [0064]      FIG. 26  shows a close-up view of a lower holder part subassembly including the illuminating insertion appliance. 
           [0065]      FIGS. 27 to 30  show a version embodiment of the lower holder part subassembly, wherein the components of an electrical circuit are incorporated immediately into a holder plastic body. 
           [0066]      FIG. 31  shows a cross-sectional view of the laryngoscope assembly in an operation position. 
           [0067]      FIG. 32  shows a cross-sectional view of the laryngoscope assembly in an inoperative position. 
           [0068]      FIGS. 33 to 38  show another version of the offered laryngoscope with a modified arrangement of an insertion portion of a lower holder part, wherein: 
           [0069]      FIG. 33  shows a detachable blade. 
           [0070]      FIG. 34  shows an upper holder part. 
           [0071]      FIG. 35  shows a subassembly of the lower holder part. 
           [0072]      FIG. 36  shows an external view of the laryngoscope in an operation position. 
           [0073]      FIG. 37  shows an external view of the laryngoscope in an inoperative position. 
           [0074]      FIG. 38  shows a cross-sectional view of the laryngoscope in the operation position. 
           [0075]      FIGS. 39 to 41  show a laryngoscope version having a modified arrangement of an insertion portion of a lower holder part and a non-detachable affixation of the lower holder part to a blade, wherein: 
           [0076]      FIG. 39  shows a subassembly of a handle and an upper holder part. 
           [0077]      FIG. 40  shows a detachable unit including the lower holder part and the blade. 
           [0078]      FIG. 41  shows an external view of the laryngoscope in an operation position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0079]    The explanation of the present invention is offered with references made to the attached drawings in  FIGS. 4 to 41 . 
         [0080]    The drawings in  FIGS. 4 to 8  show intubation laryngoscope  200  comprising handle  204  and detachable blade  201 , extending from a lower end of handle  204  in a distal direction and having blade proximal end portion  203  and blade distal end portion  202  designed to expose a tracheal entrance in order to insert an endothracheal tube therein. This blade is one of several blades having different sizes and forming a laryngoscope blade set. There is also holder  205  designed for fastening blade proximal end portion  203  to the lower end of handle  204 . Holder  205  consists of upper holder part  206  constantly immovably affixed to the lower end of handle  204  and lower holder part  207  to be movably fastened to the upper holder part and adapted for detachable connection with blade proximal end portion  203 . Laryngoscope  200  is provided with an illumination means ( FIG. 8 ) designed to illuminate a zone of the endotracheal tube insertion and including light source  255  housed in upper holder part  206  and connectable with batteries  221 ,  222  through turning means  220 . The latter is designed for turning on/off an illumination light. The illumination means also comprises light guide  217  disposed in lower holder part  207  and along with the latter forming lower holder part assembly  249 . 
         [0081]    Such lower holder part is a novelty allowing using the same single lower holder part for each blade of the blade set, thereby providing a decrease in the price of laryngoscope in comparison with the prior art, where each blade has its own lower holder part. Specifically, this novelty provides substantial design simplification and decrease in price of the detachable blades due to eliminating the lower holder part and the light guide from the blade design. At the same time, the offered lower holder part allows to maintain the movable connection of upper and lower holder parts for turning on/off the illumination light. Moreover, there is a capability of the easy laryngoscope adaptation to operation with various blade kinds by modifying only the single lower holder part without modifying the handle and upper holder part. 
         [0082]    Lower holder part  207  has an operation position and an inoperative position relative to upper holder part  206 . The operation position, shown in  FIGS. 7 ,  8 , allows an intubation execution and is characterized by substantially immovable fixation of lower holder part  207  to upper holder part  206 , substantially immovable fixation of detachable blade  201  to lower holder part  207 , and a switched-on position of turning means  220  to provide the illumination light. The inoperative position, obtained by rotating the lower holder part counter-clockwise and demonstrated subsequently with identical design in  FIG. 14 , allows attachment/detachment of detachable blade  201  to/from lower holder part  207 , provides a capability of detachment of lower holder part  207  from upper holder part  206 , and is characterized by a switched-off position of turning means  220  disconnecting light source  255  and battery  222  and thereby turning off the illumination light. Upper surface  223  of insertion portion  211  and a longitudinal axis of handle  204  are disposed substantially at right angle in the operation position, and at angle more than 90° in the inoperative position. 
         [0083]    Lower holder part  207  is detachably fastened to upper holder part  206  by a holder fastening means. The latter includes two lateral walls  208 ,  209  of upper holder part  206  spaced some distance apart and protruding downward. Axle  210  is mounted between lateral walls  208 ,  209  at a distal edge of upper holder part  206 . Lower holder part  207  has insertion portion  211  to be inserted between lateral walls  208 ,  209  with a small gap, and having hook  212  formed by groove  213 , disposed at a distal edge of insertion portion  211  and adapted to putting on axle  210  with a capability of rotating the lower holder part  207  around axle  210  to set one of the above mentioned positions of the lower holder part. There is also a holder locking means preventing lower holder part  207  from spontaneous dislocation relative to upper holder part  206  in the operation position. 
         [0084]    Turning means  220  includes movable element  218  disposed in upper holder part  206  between lateral walls  208 ,  209  at some distance from axle  210 , protruding downward from inner upper surface  224  of upper holder part  206  in the inoperative position, and interacting with lower holder part  207  so that in the operation position of lower holder part  207  the movable element  218  is dislocated upward by pressure of lower holder part  207  ( FIG. 8 ), thereby turning on the illumination light. In the inoperative position, movable element  218  is released by lower holder part  207  that leads to returning downward the movable element and thereby to turning off the illumination light. 
         [0085]    The above mentioned holder locking means comprises a detent means preventing lower holder part  207  from a spontaneous rotation around axle  210  in the operation position. The detent means includes detent recess  214  located on an inner side of at least one of lateral walls  208 ,  209 , and ball springy detent  215  mounted at a proximal edge of insertion portion  211  opposite to the edge, at which hook  212  is disposed, and having a ball adapted to enter detent recess  214  in the operation position and to come out from detent recess  214  in the inoperative position. 
         [0086]      FIGS. 9 to 17  show offered laryngoscope version  300  wherein hook  312  of lower holder part  307  has a modified form. Laryngoscopes  200  and  300  have many elements having identical design and operation and designated by figures with the same two last numerals. Therefore, the description of version  300  is mainly devoted to its distinctions. 
         [0087]    As distinct from above version, hook  312  ( FIGS. 9 ,  13 ) is formed by groove  313  having U-shaped upper portion  325  directed downward with its open side, so that inner walls  326 ,  327  of U-shaped upper portion  325  are disposed substantially in parallel with a longitudinal axis of handle  304  and interact with axle  310  thereby preventing lower holder part  307  from dislocating in a distal and proximal directions relative to upper holder part  306  in the operation position. Inner walls  326 ,  327  of U-shaped upper portion  325  of hook  312  also are disposed substantially at a right angle to upper surface  323  of insertion portion  311  of lower holder part  307  with a permissible deviation ±30° from the right angle. In other words, in the operation position, inner walls of hook  312  envelop axle  310  from above, from distal side and from proximal side, while in the prior art (laryngoscope versions  100 ) and in version  200  the hook inner walls envelop the axle from above, from below and from proximal side. This modification of hook groove  313  is novelty preventing lower holder part  307  from a dislocation relative to upper holder part  306  in the proximal and distal directions (in the prior art the hook groove restricted the dislocation only in the distal direction) and allowing the groove inner walls to fulfill the function of ball keeper  216 , shown in  FIG. 5 . As a result, ball keeper  216  and upper window  219  used for the ball keeper mounting are eliminated in lower holder part  307  that strengthens the hook and the lower holder part and reduces the laryngoscope price. 
         [0088]    In inoperative position of lower holder part  307  ( FIG. 14 ), used for disconnecting hook  312  and axle  310 , upper outer surface  328  of a hook wall is projected some upward relative to lower surface  329  of movable element  318  in its released state. In other words, in the inoperative position, surfaces  328  and  329  are disposed with some overlap in the vertical direction. As a result, lower holder part  307  is prevented from spontaneous falling out of upper holder part  306  in the inoperative position. To detach the lower holder part  307  from upper holder part  306  as well as to put hook  312  on axle  310  movable element  318  must be dislocated upward by operator. 
         [0089]    Laryngoscope  300  has a blade fastening means designed for detachable fastening the detachable blade  301  to lower holder part  307 , as well as a blade locking means preventing detachable blade  301  from disengagement from lower holder part  307  in the operation position. The blade fastening means includes blade socket  330  made as a cavity, located below blade upper operating wall  356  at blade proximal end portion  303  and opened from a proximal side, as well as fastening protrusion  331  of lower holder part  307  protruding distally of insertion portion  311 , adapted to inserting into blade socket  330  and having external configuration corresponding to an inner configuration of blade socket  330  to maximally restrict a displacement of detachable blade  301  relative to lower holder part  307  after inserting fastening protrusion  331  into blade socket  330 . Specifically, fastening protrusion  331  and blade socket  300  have a substantially rectangular form in a transversal section, providing restricting the very important transverse dimensions of blade socket  300  and fastening protrusion  331  as well as preventing twisting the detachable blade  301  during the intubation procedure. Fastening protrusion  331  serves also as a support of detachable blade  301  during the intubation procedure. As a result, the substantial decrease in the requirements for blade strength and the corresponding decrease in the thickness of blade walls and blade weight are achieved. In a longitudinal section ( FIG. 13 ), blade socket  330  and fastening protrusion  331  have a conical form easing the insertion of fastening protrusion  331  into blade socket and decreasing their vertical dimensions at their distal portions. 
         [0090]    The blade locking means includes lugs  333 ,  334  disposed on the blade proximal end.  FIGS. 15 to 17  show the process of fastening detachable blade  301  to laryngoscope holder  305 . In the first stage of the fastening ( FIG. 15 ), fastening protrusion  331  of lower holder part  307  is partly inserted into blade socket  330  in the inoperative position of lower holder part  307 , therewith the conical form of fastening protrusion  331  and blade socket  330  allow free passing the lugs  333 ,  334  past lower edge  335  of upper holder part  306 . In the second stage ( FIG. 16 ), fastening protrusion  331  is fully inserted into blade socket  330  in the inoperative position of lower holder part  307 . In the third stage ( FIG. 17 ), lower holder part  307  along with detachable blade  301  is transferred into the operation position by rotating them clockwise around axle  310 . In the operation position ( FIGS. 12 ,  13 ,  17 ), blade proximal end portion  303  is extended some proximally of proximal edge  332  of upper holder part  306  so that lugs  333 ,  334  are located proximally of proximal edge  332  of upper holder part  306  thereby preventing detachable blade  301  from displacement distally of lower holder part  307  as long as lower holder part  307  is in the operation position. In order to detach detachable blade  301  from lower holder part  307 , the latter must be transferred into the inoperative position ( FIG. 16 ) by its rotating counter-clockwise. 
         [0091]    There is an additional blade locking means designed for preventing detachable blade  301  from spontaneous detachment from lower holder part  307  in the inoperative position. This means ( FIG. 13 ) is made as latch appliance  336  including resilient leg  337  located on blade proximal end portion  303  and having latch opening  338 , as well as latch projection  339  located on lower holder part  307  and adapted to entering latch opening  338 , when fastening protrusion  331  of lower holder part  307  is inserted into blade socket  330 . To detach detachable blade  301  from lower holder part  307  in the inoperative position, some operator&#39;s effort directed distally is necessary. 
         [0092]    The offered blade locking means in the form of lugs  333 ,  334  is novelty, which along with the mentioned blade fastening means and additional blade locking means allow obtaining the extreme simple and inexpensive design of detachable blade  301  in the form of a single plastic piece. 
         [0093]    The presented above laryngoscope versions  200  and  300  are provided with the illumination means including batteries  221 ,  222  ( FIG. 3) and 321 ,  322  ( FIGS. 13 ,  14 ) located within handles  204  and  304  respectively, light sources  255  and  355  located in upper holder parts  206  and  306  respectively, and light guides  217  and  317  located in lower holder parts  207  and  307  respectively between the light source and a distal face of the lower holder part in the operation position of the lower holder part. Therewith the light source may be a conventional lamp or a light emitting device (LED). 
         [0094]    Version embodiment  400  of the offered intubation laryngoscope, shown in  FIGS. 18 to 32 , and above laryngoscopes  200 ,  300  include many elements having identical design and operation and designated by figures with the same two last numerals. Therefore, the following description of version  400  is mainly restricted with its distinctions. 
         [0095]    As distinct from the above laryngoscopes  200  and  300 , laryngoscope  400  has the illumination means ( FIG. 31 ) including batteries  421 ,  422  located within handle  404 , and light source  455  in the form of lamp or LED located in a distal end of lower holder part  407 . The batteries and light source are connectable through first lead wire  446  and second lead wire  445  located in lower holder part  407 . Therewith, first lead wire  446  connects light source  455  immediately with electrical contact  444 , which is disposed at upper surface  423  of lower holder part  407  and in the operation position of lower holder part  407  contacting with movable element  418  of turning means  420 . Movable element  418 , insulated from upper holder part  406  by movable element keeper  447  with its cover  452  made of plastic, in turn contacts with a positive pole of battery  422 . Second lead wire  445  connects light source  455  with metal contacting bushing  443 , which in the operation position of lower holder part  407  is connected with a negative pole of battery  421  through ball springy detent  415 , metallic upper holder part  406 , metallic handle  404  and spring  441 . Electrical contact  444  and contacting bushing  443  are contacting members allowing said lead wires  445 ,  446  to interact with turning means  420 . 
         [0096]    In version embodiment ( FIGS. 22 to 26 ), electrical contact  444 , contacting bushing  443 , lead wires  445 ,  446  and light source  455  are incorporated into plastic housing  442  forming the illuminating insertion appliance  449 . The latter is inserted into holder socket  450  of lower holder part  407  and fastened to it by ball springy detent  415 , thereby forming lower holder part assembly  451 . As a result, assembly  451  consists of the illuminating insertion appliance  449 , whose housing  442  is made of plastic, and lower holder part  407  made of metal or plastic. 
         [0097]    In another version embodiment, shown in  FIGS. 27 to 30 , contacting bushing  443 , electrical contact  444 , light source  455  and lead wires  445 ,  446  are incorporated immediately into plastic body  453  of lower holder part  407 , thereby forming a subassembly  454  of the lower holder part. 
         [0098]    In inoperative position of lower holder part ( FIG. 32 ), the contacts between electrical contact  444  and movable element  418  as well as between ball springy detent  415  and upper holder part  406  are interrupted and the illumination light is turned off. 
         [0099]    The batteries  421 ,  422  are constantly squeezed between spring  441  and movable element  418  thereby providing a reliable electrical contact between components  444 ,  418 ,  422 ,  421 ,  404 ,  406  in the operation position of lower holder part  407  ( FIG. 32 ). In the inoperative position ( FIG. 32 ), spring  441  continues pressing onto movable element  418  due to that the latter protrudes upward from cover  452  of movable element keeper  447 . This protrusion is provided with the ratio of the lengths of movable element  418  and keeper  447 , as well as disposition of limiting flange  448  on movable element  418 . As a result, in the inoperative position, spring  441  holds movable element  418  in an extreme lower position needed for preventing lower holder part  407  from spontaneous falling out of upper holder part  406 . Thus, batteries  421 ,  422  are contacting with movable element  418  in any position. The offered mechanism of interacting spring  441 , batteries  421 ,  422  and movable element  418  is novelty allowing simplifying the design of turning means  420  due to using only one spring  441  both as a battery holding means and as a spring of turning means  420 , as well as enhancing a reliability of the electrical circuit due to decreasing the number of disconnectable contacts, while in the identical mechanism in the prior art at least two springs as well as the disconnecting contact of the movable element and battery are used. In  FIGS. 31 ,  32  is used holder subassembly  454 , shown in  FIGS. 27 to 30  and having a plastic housing  453  eliminating a short circuit between movable element  448  and lower holder part  407  in the inoperative position ( FIG. 32 ). 
         [0100]    Version embodiment  500  of the offered intubation laryngoscope, shown in  FIGS. 33 to 38 , and above laryngoscopes  200 ,  300 ,  400  include many elements having identical design and operation and designated by figures with the same two last numerals. Therefore, the description of version  500  is mainly devoted to its distinctions. 
         [0101]    In version embodiment  500  ( FIGS. 33 to 38 ), axle  510  of upper holder part  506  is disposed in parallel to a middle plane passing through a longitudinal axis of handle  504  and a distal direction of extending the detachable blade  50 . The middle plane is a secant plane in the cross-sectional view in  FIG. 38 . Internal surfaces  556 ,  557  of two lateral walls  508 ,  509 , respectively, are disposed at right angle to the middle plane, while in the prior art and in the above laryngoscopes  200 ,  300 ,  400  the axle of upper holder part is disposed at right angle to the middle plane and two lateral walls of the upper holder part have internal surfaces disposed in parallel to the middle plane. In accordance with new arrangement of axles  510  and lateral walls  508 ,  509 , the groove  513  of hook  512  is disposed in parallel to the middle plane, and insertion portion  511  of lower holder part  507  is disposed transversely to the middle plane ( FIG. 35 ). As a result, the load of lower holder part  507 , specifically in the form of a torque acting in the middle plane and arising during the intubation procedure, to a great extent is applied to lateral walls  508 ,  509 , instead of the hook in the prior art. This leads to substantial increase of the resistance power of the lower holder part due to that walls  508 ,  509  are thicker and stronger than hook  512 . In inoperative position, shown in  FIG. 37 , upper holder part  506  along with handle  504  is some rotated around axle  510  in a plane perpendicular to the middle plane, thereby obviating obstacle for passing lug  533  and allowing putting the detachable blade  501  on lower holder part  507 . After returning in the operation position ( FIG. 36 ), lug  553  is disposed proximally of wall  508  thereby preventing detachable blade  501  from spontaneous detachment from lower holder part  507  in the operation position. 
         [0102]    The offered arrangement of axle  510 , hook grove  513 , insertion part  511  and lateral walls  508 ,  509  is novelty allowing maximal reduction of the requirements for the strength of lower holder part  507 , specifically for the strength of hook  512 , due to the redistribution of the load between the elements of the lower holder part. As a result, the capability of manufacturing the plastic lower holder part, having sufficient strength, is achieved. 
         [0103]    In another versions of laryngoscope  500  (not shown), the angle between axle  510  and the middle plane is acute, for example it is equal to 45°, with corresponding changes of the disposition of another elements such as  511 ,  513 ,  508 ,  509  relative to the middle plane. Therewith, the less is this acute angle the more is the resistance power of the lower holder part. The maximal resistance power of the lower holder part is achieved when the mentioned angle is equal to zero, i.e. in the version, shown in  FIGS. 34 to 38 . The necessity of some increasing the mentioned angle more than zero may be caused with the need for some enhancing the operation effectiveness of the detent means, specifically ball spring detent  515 . 
         [0104]    All above presented laryngoscope versions  200 ,  300 ,  400 ,  500  have the illumination system, wherein all components of the illumination means are disposed in a laryngoscope subassembly consisting of the handle and the both holder parts. 
         [0105]    The modified arrangement of the axle and other elements of the upper and lower holder parts, shown in  FIGS. 33 to 38 , in principle, may be also applied to the laryngoscopes, which are beyond the offered laryngoscopes having the lower holder part detachable from the blade. Specifically,  FIGS. 39 to 41  show laryngoscope  600 , wherein lower holder part  607  is constantly attached to bade  601  and along with the blade is detachable from upper holder part  606  identically to laryngoscope  100  of the prior art. However, the arrangement of axle  610 , lateral walls  608 ,  609 , insertion portion  611  and groove  613  of hook  612  is identical to one of above laryngoscope  500 . Laryngoscopes  500  and  600  have the same two last numerals of the identical element designations. This allows applying the description of the peculiarity of laryngoscope  500  also to laryngoscope  600 . Specifically, the offered arrangement of axle  610  and the other above pointed elements allows considerable reduction in the requirements for the strength of lower holder part  607 , specifically for the strength of hook  612 , due to the redistribution of the load between the elements of lower holder part  607 . As a result, the capability of manufacturing plastic lower holder part  607 , as well as a plastic unit of lower holder part  607  and blade  601  as a whole, having sufficient strength, is achieved.