Abstract:
A bite block that is inserted into a patient&#39;s mouth during an endoscopic diagnostic or surgical procedure that has a channel for receiving an endoscope or other surgical instrument through the patient&#39;s mouth and additional channels transmitting a gas to the patient and transmitting expired gas from the patient.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority benefit of U.S. provisional patent application Ser. No. 60/941,707, filed on Jun. 4, 2007, the contents of which are incorporated by reference in their entirety herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to bite blocks for use in endoscopic surgical procedures, and in particular, to endoscopic bite blocks for use in procedures involving sedation and analgesia systems. 
     BACKGROUND OF THE INVENTION 
     During some medical procedures, specifically endoscopic procedures, it is necessary to insert medical instruments, such as an endoscope, into the mouth and down the trachea or esophagus of a patient. It is common to use in such procedures a bite block or mouthguard to protect both the patient&#39;s mouth from the endoscope and the endoscope from the patient&#39;s mouth. The bite block or mouthguard essentially maintains the patient&#39;s mouth in the open position, providing an opening through which the endoscope can be passed, and prevents the patient from biting down on the endoscopic instruments, which are often quite expensive. Bite blocks capable of such function are generally known in the art; bite blocks designed for use with sedation and analgesia delivery and patient monitoring systems, however, are not. 
     In order to increase comfort and reduce patient resistance to the advancing of the scope, patients are often sedated during endoscopic procedures. In the case when the particular sedation drugs are respiratory depressants, there exist certain well-known risks related to patient respiration, including hypoventilation, oxygen desaturation, and apnea. In order to mitigate these risks, supplementary oxygen and respiratory monitoring are often utilized. Both the administration of supplementary oxygen and the sampling of respiratory gasses for monitoring require access to the patient&#39;s respiratory orifices, usually accomplished via oral-nasal cannula. Difficulties sometimes arise, however, when simultaneously managing the scope, delivering supplementary oxygen, and sampling respiratory gasses via the oral cavity. If the oral cavity could be reserved for exclusive use by the endoscope and the nasal passages used for oxygen delivery and respiratory sampling, the difficulty would be greatly reduced. Unfortunately, this method would require that the patient inhale and exhale only through the nasal passages for the duration of the procedure; in a real-world scenario, however, this is not the case. 
     It is therefore desirable for endoscopic procedures that require sedation to allow maneuvering of an endoscope into the oral cavity simultaneous with oral and nasal oxygen delivery and expired gas sampling. It indeed requires little imagination to see that accommodating all three activities simultaneously through the oral cavity with instruments not designed to be used together would prove troublesome. It follows that, as the endoscopy is the main focus of the procedure, it would take priority in use of the oral cavity over the other two functions. While focusing on the endoscope, an oral-nasal cannula is rather easily bumped and relocated during the maneuvering of the scope, leaving its oral ports situated too far from the oral cavity and occasionally causing bruising internal to the nasal passages. The consequence is decreased effectiveness in the administration of supplementary oxygen and sampling of respiratory gasses, which in turn may compromise patient safety. 
     In addition, in current practice, some doctors use a finger to help guide the endoscope into the mouth and down the trachea or esophagus of the patient. To do so, a doctor may stick a finger inside a patient&#39;s mouth, outside of the bite block, in order to control the endoscope near the opening to the trachea or esophagus. This requires that the finger be inserted at least to the depth of the end of the bite block, which may cause the bite block to move around. This adds to the risk that, during all of the jostling of the bite block associated with the maneuvering of the endoscope and insertion of a finger, the oral ports of the cannula may be unintentionally relocated away from the oral cavity. 
     It is therefore the object of the present invention to provide a bite block with means for locating and protecting the oral ports of an oral-nasal cannula and to facilitate simultaneous use of the oral cavity for an endoscopic diagnostic or surgical procedure, supplemental oxygen delivery, and respiratory sampling. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a front perspective view of a bite block in accordance with the present invention; 
         FIG. 2  is back perspective view of a bite block in accordance with the present invention; 
         FIG. 3  is a side view of a bite block in accordance with the present invention, shown in a section view of a patient&#39;s mouth; 
         FIG. 4  is a perspective view of a bite block in accordance with the present invention and a typical oral-nasal cannula, shown together, interfaced as they would be used during a procedure; 
         FIG. 5  is a front view of a bite block in accordance with the present invention; 
         FIG. 6  is a side section view of a bite block in accordance with the present invention and a typical oral-nasal cannula, shown together, interfaced as they would be used during a procedure; and 
         FIG. 7  is a rear perspective view of an alternate embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1  and  FIG. 2 , the bite block  8  of the present invention consists of a generally elliptical cylindrical main body  20 , having a proximal end, which sits outside of a patient&#39;s mouth, and a distal end, which sits inside a patient&#39;s mouth. Main body  20  surrounds main oral passage lumen or channel  7 , which is sized to allow for passage of an endoscope and ventilation of the patient. Oral passage  7  is defined by a lower surface  7   a  and an upper surface  7   b  ( FIG. 5 ). Upper surface  7   b  further defines an opening for internal gas channel or lumen  10  ( FIG. 5 ). Integral to the proximal end of main body  20  is flange  14 , which sits outside of a patient&#39;s lips and serves both to locate bite block  8  relative to the patient&#39;s mouth and protect the patient&#39;s lips and teeth from an endoscope. Flange  14  is integral to main body  20  at distal surface  22 . Attached at each side of flange  14  is strap attachment wing  6  for strap  19  that goes around the patient&#39;s head and helps secure bite block  8 . 
     Referring to  FIG. 3 , extending from the proximal to distal end of main body  20 , are a raised top surface  17  and bottom surface  18  for seating patient&#39;s upper teeth and lower teeth, respectively. Located at the distal end of top surface  17  is upper protruding retention feature  9 , protruding up generally perpendicular to top surface  17 . Upper protruding retention feature  9  serves as a stop to keep bite block  8  from being expelled from a patient&#39;s mouth by requiring the mouth (or more particularly, the teeth) to be opened wide enough to get around retention feature  9 . Similarly, on bottom surface  18  is lower protruding retention feature  11  serving the same purpose. 
     Referring also now to  FIGS. 4 and 6 , some features of the present invention are intended to interface with an oral-nasal cannula  1 , generally known in the art, with oxygen outlet port  2  and CO 2  sampling inlet port  3 . A representative oral-nasal cannula is described in pending application US-2006-0042636, the contents of which are incorporated by reference in its entirety herein. Oxygen outlet port  2  is the end of the oxygen delivery fluid line that delivers oxygen into the patient&#39;s oral cavity, and CO 2  sampling inlet port  3  is the end of the fluid line of a capnometry or capnography system through which expired CO 2  enters from a patient&#39;s oral cavity. Oxygen outlet port  2  and CO 2  sampling inlet port  3  consist of tubular extensions downward from the main body of cannula  1 , bent in a generally perpendicular fashion towards the patient&#39;s mouth. In the absence of a bite block, the openings of oxygen outlet port  2  and CO 2  sampling inlet port  3  would rest at the opening to the oral cavity. 
     Referring also now to  FIG. 5 , internal to main body  20 , and extending from the proximal end to the distal end of main body  20 , and adjacent to main oral passage  7 , is internal gas channel  10 . Internal gas channel  10  consists of two parallel adjacently-connected sub-channels  10   a  and  10   b , each of semi-circular cross section, which define a top surface  17   a . Internal gas channel  10  occupies the area under raised surface  17 . Internal gas channel  10  allows the exchange of gas from the proximal end (external to the patient&#39;s mouth) of bite block  8  to the distal end (internal to the patient&#39;s mouth), and vice versa, without using a significant amount of the cross-sectional area of main oral passage  7 , which is reserved for use by the endoscope. As seen in  FIG. 4 , internal gas channel  10  provides a path via one sub-channel  10   a  (for example) for oxygen to flow from oxygen outlet port  2  of an oral-nasal cannula  1  into the patient&#39;s mouth and, via the other sub-channel  10   b  (for example), for CO 2  to flow from the patient&#39;s mouth into CO 2  sampling inlet port  3  of cannula  1 . The sub-channels  10   a ,  10   b  of internal gas channel  10  can be used interchangeably for either oxygen or CO 2 , depending on where the respective ports are located on cannula  1 . 
     Oxygen port support  4  and CO 2  port support  5  protrude from proximal surface  21  of flange  14 , and proximal from internal gas channel  10 . Oxygen port support  4  and CO 2  port support  5 , each consist of a generally flat extension extending from proximal surface  21 , and generally symmetrical with respect to the vertical plane aligned longitudinally along main body  20 . From their points of attachment located on the side away from the center axis of main body  20 , oxygen port support  4  and CO 2  port support  5  slope slightly downward toward the center of main oral passage  7 . Oxygen port support  4  and CO 2  port support  5  also extend in the distal direction for approximately the thickness of flange  14 , as best seen in  FIGS. 1 and 6 , partially separating main oral passage  7  and internal gas channel  10 . This arrangement is designed to allow the ends of oxygen outlet port  2  and CO 2  sampling inlet port  3  of cannula  1  to rest inside internal gas channel  10 , as shown in  FIG. 6 . Oxygen port support  4  and CO 2  port support  5  each terminate on their proximal ends in an upward-curving quarter-circular shaped feature, which provides a means for more securely locating near the oral cavity oxygen outlet port  2  of the oxygen delivery system and CO 2  sampling inlet port  3  of a capnometry or capnography system. Oxygen port support  4  and CO 2  port support  5  are intended to provide a means for protecting the location of oxygen outlet port  2  and CO 2  sampling inlet port  3  against jostling from the movement of the scope. The terms “oxygen port support” and “CO 2  port support” are used only illustratively in this description; since the supports are generally symmetrical, they could be used interchangeably, depending on which side of cannula  1  each port was located. 
     An alternate embodiment of the present invention, shown in  FIG. 7 , adds additional functionality by allowing a doctor to insert a finger a short distance into the patient&#39;s mouth to help guide the endoscope down into the trachea or esophagus, while again preventing excessive jostling of bite block  8  and cannula  1 . In the alternate embodiment, main body  20  has curved cutouts  23  on its distal end, on both of its sides. In addition, integral to flange  14 , and extending out on both of its sides, are strap attachment wing extenders  24 , each consisting of a thin arced, ‘c’-shaped protrusion, defining an opening. Cutouts  23  and strap attachment wing extenders  24  are sized and located such that a finger may be inserted through the open side of the ‘c’ of strap attachment wing extender  24  and past cutout  23  into the patient&#39;s mouth. Strap attachment wing extenders  24  also locate the strap attachment wings  6  such that the strap is not in the way of a finger. In this manner, a doctor would be able to easily guide an endoscope with a finger without using any of the cross sectional area of main oral passage  7 , and without too much jostling of bite block  8  and cannula  1 . 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.