Abstract:
A medical apparatus that holds open a mouth of a patient. The apparatus contains a passage through which the patient can breathe by mouth. The apparatus contains a port to which an oxygen line is connected and which delivers oxygen to the passage for inhalation by the patient. The apparatus contains a sampling port which samples air in the passage and delivers sampled air to a monitoring device. The latter measures, for example, carbon dioxide content in the sampled gas, and issues a warning if carbon dioxide concentration is out-of-bounds. Phosphor material can be added to the apparatus, to make the apparatus glow in a darkened operating room, to allow technicians to easily find the patient&#39;s mouth and to insert tools, tubing, instruments and the like in the patient&#39;s mouth.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention concerns an appliance which comfortably holds open the mouth of a patient during a medical or surgical procedure, delivers breathable oxygen to the patient and samples carbon dioxide concentration in the air exhaled by the patient. 
         [0003]    2. Description of the Related Art 
         [0004]    During medical procedures, a device is sometimes used to hold open a patient&#39;s mouth while providing an airway through which the patient can breathe normally. Such devices or appliances are sometimes called endoscopic mouth guards or bite blocks. The airway also provides access for medical personnel to insert various devices, such as tubing, into the patient&#39;s mouth or throat for various purposes. This bite block facilitates protecting instruments, endoscopes, tubing, tools and the like from being bitten by the patient. 
         [0005]    U.S. Pat. Nos. 6,926,005, RE38,728, 6,491,643, 6,422,240, 6,186,958, 5,857,461, 5,174,284, 5,513,634, 348, 932, 329,901, 4,944,313, 4,640,273, and Publication Nos. 2005/0279362, 2005/0273016 show various prior art devices relating to bite blocks and similar devices used in the past. 
         [0006]    The invention offers advancements upon one or more of such devices. 
       SUMMARY OF THE INVENTION 
       [0007]    An object of the invention is to provide an improved medical device or appliance which holds open a patient&#39;s mouth during medical procedures. 
         [0008]    In one form of the invention, a mouthpiece is provided which holds open a patient&#39;s mouth, offers a passage through which the patient can breathe and through which medical devices can be inserted into the mouth and throat, delivers a stream of oxygen to the passage for the patient to breathe, and samples exhaled gases from the patient, to indicate the concentration of carbon dioxide in the patient&#39;s lungs for diagnostic purposes. 
         [0009]    In another form, this invention comprises a medical apparatus, comprising: 
         [0000]    a) an appliance which holds open a patient&#39;s mouth, comprising:
       i) a passage through which the patient can breathe ambient atmospheric air;   ii) a conduit effective to deliver oxygen from an external supply to the passage, and
 
b) an outlet conduit which connects to the passage, and extracts some air from the passage and delivers extracted air to a gas-monitoring apparatus.
       
 
         [0012]    In still another form, this invention comprises a medical apparatus, comprising: 
         [0000]    a) a body which fits into a patient&#39;s mouth and contains a passage through which the patient can breathe ambient atmospheric air;
 
b) a first conduit which connects the passage with an oxygen port; and
 
c) a second conduit which connects the passage with a sampling port.
 
         [0013]    In yet another form, this invention comprises a medical apparatus, comprising: 
         [0000]    a) an appliance which
       i) holds open a patient&#39;s mouth, and ii) provides a passage through which the patient can breathe ambient atmospheric air normally;
 
b) a manifold supported by the appliance, comprising:
   i) a first set of star-connected conduits, wherein
           A) a first conduit leads to an oxygen port,   B) a second conduit leads to the passage, and   C) a third conduit leads to a chamber;   
           ii) a second set of star-connected conduits, wherein
           A) a fourth conduit leads to a sampling port,   B) a fifth conduit leads to the passage, and   C) a sixth conduit leads to the chamber.   
               
 
         [0023]    In another form this invention comprises a method, comprising: 
         [0000]    a) maintaining a body within a patient&#39;s mouth which provides a passage through which the patient can breathe ambient atmospheric air;
 
b) delivering oxygen to the passage, for inhalation by the patient; and
 
c) sampling air in the passage, and detecting concentration of a gas in sampled air.
 
         [0024]    In yet another form this invention comprises a medical apparatus, comprising: 
         [0000]    a) an appliance which holds open a patient&#39;s mouth, which includes a passage through which the patient can breathe ambient atmospheric air;
 
b) an oxygen conduit in the appliance which delivers oxygen to the patient&#39;s mouth and nose;
 
c) a sampling conduit which samples air exhaled by the patient, and which is positioned such that exhaled air inhibits oxygen delivered by the oxygen conduit from reaching the sampling conduit.
 
         [0025]    These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  illustrates one form of the invention in the form of a bite block or manifold, fastened to the face of a patient; 
           [0027]      FIG. 2  is a cross-sectional view of the device of  FIG. 1  taken along the line  2 - 2  in  FIG. 1 ; 
           [0028]      FIG. 3  is a perspective view of the device of  FIG. 1 , viewed from a front of the device, that is, viewed by a person facing the patient; 
           [0029]      FIG. 4  is a perspective view of the device of  FIG. 1 , viewed from the rear of the device which is placed inside the mouth of the patient; 
           [0030]      FIG. 5  is a sectional perspective view of the device of  FIG. 3 , viewed in the direction of line  5 - 5  point in  FIG. 3 ; 
           [0031]      FIG. 6  is a sectional perspective view of the device of  FIG. 3 , viewed in the direction of line  6 - 6  point in  FIG. 3 ; 
           [0032]      FIG. 7  is a cross-sectional view of the device of  FIG. 4 , taken in the direction of line  7 - 7  in  FIG. 4 ; 
           [0033]      FIG. 8A  is a simplified and diagrammatic view providing and explanation of how carbon dioxide measured by the invention may vary during inhalation and exhalation of a patient; 
           [0034]      FIG. 8B  is a graph illustrating a CO 2  versus time of the inhalation and exhalation of a patient; 
           [0035]      FIGS. 9-11  are simplified diagrammatic representations of a plurality of passageways, flow paths, conduits or channels within the bite block or manifold of  FIG. 1 ; 
           [0036]      FIG. 12  is a diagrammatic representation of a plurality of passageways, illustrating air being exhaled from a nose of a patient toward a receiving area of the bite block or manifold in  FIG. 1 ; and 
           [0037]      FIG. 13  is a diagrammatic representation of a plurality of passageways, illustrating air being exhaled from the mouth of a patient toward the bite block or manifold in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0038]      FIG. 1  illustrates a system for directing oxygen and providing diagnostic information relative to a patient. The system comprises a bite block, appliance, bite block, manifold or mouthpiece  10 . The bite block  10  is an integral one-piece molded construction, which for ease of reference shall be referred to as bite block  10 . In one embodiment, the bite block  10  is molded from a thermoplastic or polymer material, such as a polypropylene, polyethylene or other material. In one embodiment, it is preferable that the material be approved by the United States Food and Drug Administration. To produce or mold the bite block  10 , a multi-cavity plastic injection mold (not shown) is used. The mold is placed in a conventional plastic injection molding press (not shown) to process. A high pressure injection of, for example, a thermoplastic material that has been melted at a high temperature is injected into the mold. Typically, the mold is cooled with cold water to cure the plastic to form the bite block  10  in approximate thirty seconds. This cycle is then repeated over and over. 
         [0039]    The bite block  10  comprises an inlet port, connecting portion or member  12  and sampling port, outlet port, connecting portion or member  14 . As illustrated in  FIG. 1 , the inlet port, connecting portion or member  12  is coupled to an oxygen supply  16  via an oxygen line or tubing  18  having a nipple or end portion  18   a  coupled to the inlet port, connecting portion or member  12  as shown. The outlet port, connecting portion or member  14  has a threaded end or coupling  14   a  ( FIG. 4 ) that is connected to a monitoring system  20  via a suitable line or tubing  22  and adapted or configured to mate with a conventional quick-connect connector  24 . 
         [0040]    The oxygen line  18  originates in the oxygen supply  16  and is coupled to and in fluid communication therewith so that oxygen may be provided therefrom, through the line  18  and to an inlet, conduit or passageway  28  defined by a wall  12   a  ( FIG. 1 ) of the connecting portion  12 . The passageway  28  directs the fluid, such as oxygen, into and through at least one or a plurality of passageways, conduits, channels or ducts  34  and  36  associated with a mouth and nose, respectively, of a patient. The passageways or channels  34  and  36  ( FIG. 6 ) are defined by walls  38  and  40 , respectively, that are integrally formed in the bite block  10 . The oxygen supply  16  can take the form of an oxygen tank (not shown) to which is attached a pressure regulator (not shown), which regulates oxygen through line  18 . Advantageously, the circuit of conduits and passageways  28 ,  34  and  36  provide a substantially constant oxygen supply to the patient&#39;s nose N and oral/throat passage. 
         [0041]    The sampling or outlet port  14  is coupled to the tubing  22  and provides an outlet conduit or passageway  32  defined by wall  14   a  adapted to extract or receive fluid or fluid samples, such as CO 2 , from the patient&#39;s nose and throat via at least one or a plurality of passageways, conduits, channels or ducts  42  and  44 , described later herein relative to  FIG. 5 . The fluid or samples are delivered via tubing  22  to the monitoring system  20 . These channels  42  and  44  are defined by walls  46  and  48 , respectively, as shown, which are also integrally formed in the bite block  10 . In the illustration being described, the monitoring system  20  measures carbon dioxide concentration in the samples or patient&#39;s exhale received in the line  22 . Carbon dioxide monitoring systems are commercially available from manufacturers, such as Nellcor Incorporated of Pleasanton, Calif.; Welch Allyn, Inc. of Skaneateles Falls, N.Y.; and Hewlett-Packard Company of Palo Alto, Calif. For example, one monitoring system  20  may comprise the Model No HP M1026A available from Hewlett-Packard Company of Palo Alto, Calif. 
         [0042]    Another feature of the illustrative embodiment, as shown in  FIG. 1 , is that the inlet port  12  and outlet port  14  have indicia applied thereto, embossed or integrally molded therein that indicates the fluid (“O 2 ” and “CO 2 ” in the illustration being described) to be received in the inlet passageway  28  and outlet passageway  32  ( FIG. 4 ). 
         [0043]    As shown in  FIG. 2 , the bite block  10  contains a generally cylindrical, curved or an annular body  51  which comprises a wall  56  that defines or surrounds the internal air or primary passageway  54 . In one illustration, the wall  56  comprises a general diameter of about 22 millimeters for ease of instrument access, tool or tubing insertion and the like. For example, in the illustration, the primary passageway  54  is adapted to receive a number  60  esophageal dilator. 
         [0044]    Notice in  FIGS. 2 ,  5  and  6  that the bite block  10  comprises an oval-shaped wall  49  that extends radially away from an axis A ( FIG. 2 ). The wall  49  defines a common opening, aperture or area  50  that defines or provides a well or receiving area that becomes operatively positioned beneath the nose N ( FIG. 2 ) of the patient after the bite block  10  is inserted into the patient&#39;s mouth as described later herein. Notice that the area  50  provides fluid communication to the passageways  36  and  44 . This area  50  becomes associated with a patient&#39;s nose N, as illustrated in  FIGS. 1 and 2 , during use of the bite block  10 . Notice also that the channels, conduits or passageways  34  and  42  are in fluid communication with the opening  50  defined by the wall  56  which is integrally formed in the bite block  10 . 
         [0045]    In the illustration being described, the wall  56  is generally arcuate or curved in cross-section along its longitudinal axis as shown in  FIGS. 5 and 6 . The wall  56  is generally circular or oval shaped, as viewed in  FIG. 7 , in a cross-section perpendicular to its axis. The opening  50  is in communication with the patient&#39;s oral cavity, throat or mouth M. Notice that the wall  56  has an upper area or surface  56   a  ( FIG. 5 ) that becomes situated in proximity to that patient&#39;s upper jaw UJ ( FIG. 2 ) and teeth  58 . The wall  56  also has a bottom area or surface  56   b  that becomes associated with a lower jaw LJ and teeth  59 . The wall  56  facilitates retaining the mouth in an open position. This permits, among other things, the patient&#39;s mouth M to be retained in an open position so that tubing, instruments, tools, dilators or other items (not shown) may be inserted through the opening  50  and into the throat of the patient. 
         [0046]      FIGS. 9 and 10  illustrate that during operation, fluids, such as oxygen, enter conduit  28  from tubing  18  and exits into the patient&#39;s mouth M via conduit  34  and toward the patient&#39;s nose via conduit  36  for inhaling by the patient. Sampled fluid, such as the patient&#39;s exhaled gas or breath (represented by CO 2  in  FIG. 1 ), enters or is received in passageways or conduits  42  and  44 . The patient&#39;s exhale is received in passageway or conduit  32  and received in tube  22  and ultimately received by the monitoring system  20 . 
         [0047]      FIGS. 9-13  are simplified diagrammatic representations of the bite block  10  of the fluid circuit and passageways in bite block  10  of  FIG. 1 . The figures illustrate that at least one inlet passageway comprising one or more passageways, ducts or channels  28 ,  34  and  36  that are connected together and in fluid communication; that is, fluid is free to flow from any of the three ducts into any other of the three ducts (subject, of course, to pressure gradients which may be present). At least one outlet passageway, comprising the plurality of passageways, ducts or channels  32 ,  42  and  44  are similarly connected together and in fluid communication. 
         [0048]    As best illustrated in  FIGS. 9-11 , note that the first inlet passageway comprises the first leg portion  29  that defines the first passageway, duct or channel  28 , a second leg portion  31  that defines the second passageway, duct or channel  36  and a third leg portion  33  that defines the third passageway, duct or channel  36 . Note that the first, second and third leg portions are in fluid communication yet their respective axes are not coaxial. Likewise, the at least one outlet passageway comprises the fourth leg portion  35 , fifth leg portion  37  and sixth leg potion  39 , which define the passageways  32 ,  44  and  42 , respectively. Note that the fourth leg portion  35 , fifth leg portion  37  and sixth leg portion  39  are in fluid communication and also have axes that are not coaxial. 
         [0049]    As illustrated diagrammatically by the  FIGS. 9-11 , the first leg portion  29  defines the passageway  28  that receives fluid, such as oxygen, from the fluid source or supply  16  ( FIG. 1 ) and may deliver it to at least one or both of the passageway, duct or channel  36  defined by second leg portion  31 , and passageway, duct or channel  34  defined by third leg portion  33 . In the illustration being described, the second and third leg portions  31  and  33  are adapted or arranged to deliver the fluid to at least one or both of the nose and mouth, respectively, of the patient. Although not shown, it should be appreciated that more or fewer outlets or leg portions may be provided. For example, the bite block  10  could be molded to provide a passageway that comprises just leg portions  29  and  31  or  29  and  33  in combination so that the inlet passageway only delivers fluid to the nose or mouth, respectively. In one embodiment, the inlet passageway is defined by walls  12   a ,  38  and  40  and the outlet passageway is defined by walls  14   a ,  46  and  48 . The walls  12   a ,  38 ,  40 ,  14   a ,  46  and  48  may be integrally formed onto bite block  10 . Although not shown, the inlet and outlet passageways may be provided as a separate assembly. However, in the illustration being described, the bite block  10  comprises the passageway  28  that delivers fluid to both the mouth and the nose of the patient. 
         [0050]    Similarly, the at least one outlet passageway may receive fluid from both the mouth and nose of the patient after the bite block  10  is inserted into the patient&#39;s mouth. Thus, the fifth leg portion  37  may receive exhaled air, for example, into passageway  44  from the patient&#39;s nose, while fluid, such as exhaled air, may be received in the sixth leg portion  39  and passageway  42  from the patient&#39;s mouth. As mentioned earlier herein, note that the leg portions  35 ,  37  and  39  are in fluid communication and have axes that are not coaxial. In one embodiment, the axes of the respective leg portions  29 - 39  may be situated at angles such that the outlet of the leg portions  31  and  37  are in proximity to the patient&#39;s nose, while the outlets of leg portions  33  and  39  become associated with the patient&#39;s mouth. 
         [0051]    As shown in  FIG. 10 , passageways, channels or ducts  36  and  44  communicate, via the area  50 , to provide oxygen to one or both nostrils of the patient&#39;s nose N ( FIG. 1 ). As mentioned later herein, the passageways or ducts  34  and  42  may define a Y-shaped or star-shaped connection. These passageways, channels or ducts  36  and  44  are also shown in  FIG. 4 . As shown in  FIGS. 7 and 11 , passageways or ducts  34  and  42  communicate with the patient&#39;s mouth, throat or oral cavity. These ducts  34  and  42  are also shown diagrammatically in  FIGS. 9-13 . Notice that  FIG. 2  shows the communication of duct  44  with the nose and duct  42  with the mouth. 
         [0052]    The bite block  10  in  FIG. 1  may contain at least one or a plurality of molded strap, holders, connectors or ears  55  in  FIGS. 1 and 7 , to which is attached a band (such as a latex-free band), Velcro® strip or other elastic strap or band  57  (shown in phantom in  FIG. 1 ), which retains the bite block  10  in position to the head of the patient. It should be understood, however, that the bite block  10  may be used with or without straps. 
         [0053]    A generally planar wall  64  extends radially from the bottom surface  56   b  and lies in a plane P that is generally perpendicular to an axis A of said bite block  10 . Notice that a first surface  64   a  abuts the lips L or the teeth  59 , or both lips L and teeth  58  and  59 , of the patient, and is held in place by the combined action of the lips, teeth, and the band  57  ( FIG. 1 ). A pair of generally opposed, crescent-shaped lip retainer walls or flanges  66   a  and  66   b  ( FIGS. 2 and 6 ) are integrally molded onto wall  56  and provides means and apparatus for a bottom lip and a top lip, respectfully of the patient between wall  64  and flanges  66   a  and  66   b.    
         [0054]    In operation, the bite block  10  receives incoming oxygen in passageway or duct  28 , as illustrated in  FIGS. 1 and 9 . The incoming oxygen is directed to exit passageways or ducts  34  and  36 , which deliver the oxygen to the oral cavity or mouth and nose, respectively, as illustrated diagrammatically in  FIGS. 10 and 11 . The patient breathes the incoming oxygen, together with ambient air drawn through passageway  54  and area  50  in  FIG. 2 . 
         [0055]    During exhalation, the patient exhales air from the nose, the mouth, or both, as indicated in  FIGS. 9-11 , part of which may be captured by the passageways or ducts  42  and  44 , respectively. The captured air forms a sample, which is delivered to the passageway  32  ( FIGS. 9 and 10 ) and, thereafter, to line  22  in  FIG. 1 . As mentioned earlier, line  22  leads to the monitoring system  20  which measures a gas concentration, such as carbon dioxide concentration, in the exhaled air. Concentration generally refers to the amount of carbon dioxide present per unit of exhaled air, in units such as parts per hundred by volume, for example. 
         [0056]    A possible source of error in measuring the carbon dioxide concentration will now be discussed. If no oxygen is being delivered from passageway  28  in  FIG. 1 , then the air sampled through connecting portion  14  and on line  22  will accurately represent the air exhaled from the patient&#39;s lungs. However, a possible source of error lies in ambient air which may also enter the connecting portion  14  and line  22 . This ambient air can enter passageway  54  in  FIG. 2  from the left side of  FIG. 5 , or it may leak through the interface between the bite block  10  and the patient&#39;s cheek or lips. This ambient air may then reach the outlet or sampling port  14  in  FIG. 4  via conduit  42 , for example, thereby diluting the sample. However, this stray ambient air may be considered insignificant in amount, so that the sampled air in line  22  is considered an accurate representation of the exhaled air in the patient&#39;s lungs. 
         [0057]    The stray ambient air may be considered insignificant for at least two reasons. One is that the seal between the bite block  10  and the patient&#39;s face is considered very good. The bite block  10  provides a tight fit between the patient&#39;s lips and the wall  64 . 
         [0058]    A second reason is that, as explained below, during the exhalation phase of the patient&#39;s breathing, exhaled air is moving out of the passageway  54  (i.e., from right to left in  FIG. 2 ), thereby blocking ambient air from entering passageway  54 , contrary to the situation considered above. 
         [0059]    The situation just discussed presumed that no oxygen was being delivered on line  18  in  FIG. 1 . If, on the other hand, oxygen is being delivered on line  18  in  FIG. 1 , then, in theory, the air being exhaled through passageway  54  in  FIG. 2  can be diluted by the oxygen delivered through the passageway or duct  34 . Also, it is possible that oxygen present in the passageway or duct  44  in  FIG. 4 , which is intended to reach the nose, can travel to the passageway or duct  36 , through the well; opening or area  50 , also shown in  FIGS. 7 and 11 . This dilution, in theory, may cause the carbon dioxide concentration measured by the monitoring system  20  to be incorrectly low. 
         [0060]    However, this dilution issue is not seen to be of significance because the monitoring system  20  is capable of detecting low levels of CO 2 , which provides an indication that the patient is breathing During a medical procedure, it is typically only desired or important to monitor for confirming that the patient is breathing. 
         [0061]    Even if oxygen flow is not blocked as in the two approaches just outlined, the structure of the bite block  10  itself tends to block migration of oxygen from the passageway or ducts  34  and  36  in  FIG. 10  to ducts  42  and  44 , respectively, during the exhalation cycle. During exhalation, for oxygen exiting conduit  36  in  FIG. 12  to reach conduit  32  through area  50 , the oxygen must overcome the pressure or flow from the nose, indicated by the dashed arrows. Only a very small amount of oxygen, if any, will successfully overcome this flow and reach conduit  32 . 
         [0062]    Similarly, for oxygen exiting conduit  34  in  FIG. 13  to reach conduit  42 , it must cross and overcome the exhalation flow indicated by the dashed arrows, analogous to a boat crossing a current in a flowing river. The exhalation flow will drive the oxygen out of passageway  54  ( FIG. 2 ) before the oxygen can make the lateral transit in  FIG. 13  from conduit  34  to conduit  42 . It should be appreciated that the monitoring system  20  can sense CO 2  from either or both the mouth and the nose. 
         [0063]    Therefore, the structure, design and placement of the passageways  28 ,  34 ,  36  and  32 ,  44  and  42  is thought to have the advantage of dilution of the sampled gas obtained in conduit  32  by incoming oxygen. Exhaled air tends to drive incoming oxygen away from the sampling conduits  42  and  44 . 
         [0064]    In addition, another resolution to the dilution issue lies in the fact that the amount of oxygen passing through conduit  28  in  FIGS. 9 and 10  is relatively small. Even if all this oxygen is mixed into the exhaled air, thereby diluting the exhaled air, the resulting dilution will be small, but the monitoring system  20  is sensitive enough that it is capable of detecting small amounts of CO 2 . 
         [0065]    It is noted that the carbon dioxide concentration, as measured by the present invention, will not be constant, as will be explained with reference to  FIGS. 8A and 8B .  FIG. 8A  figuratively shows one breath cycle: inhalation, wherein the lungs L expand in the illustration, followed by exhalation, wherein the lungs L contract. 
         [0066]    During inhalation, the bite block  10  will sample ambient air, that is, air originating from point P 1  on the left side of the  FIG. 8A . Consequently, the measured carbon dioxide concentration will be that of ambient air, at a first level, such as L 1  in the plot shown in  FIG. 8B . Inhalation ends at time T 1  in the plot. 
         [0067]    Then, during exhalation, the air in the mouth, throat, and larynx will be first expelled. This air is indicated by dashed block  70  in  FIG. 8B . The carbon dioxide concentration in this air should also equal that of the ambient air because, with respect to this air, no gas exchange has occurred in the lungs. This expulsion occurs for a length of time T 2 , indicated in the graph shown in  FIG. 8B . Measured carbon dioxide concentration remains the same as previous, as indicated. 
         [0068]    Then air from the lungs, represented by outgoing air passing points P 2  and P 3  is expelled. This air contains carbon dioxide from the patient&#39;s metabolism, and measured carbon dioxide will increase to a level, such as level L 2  as indicated in  FIG. 8B . 
         [0069]    Therefore, this simplified explanation illustrates that if air is sampled during the full inhalation-exhalation cycle of the patient, measured carbon dioxide concentration will indicate two general levels, which alternate with each other: (1) the level in the ambient air and (2) the level in the patient&#39;s lungs. This can be considered by the technician, or apparatus, which adjusts the rate of oxygen flow, based on the carbon dioxide concentration. For example, the technician may use an average value of the two levels L 1  and L 2  as indicating the relevant carbon dioxide concentration or oxygen level. 
         [0070]    In one form of the invention, the monitoring system  20  in  FIG. 1  detects whether carbon dioxide concentration (1) rises above a limit, (2) falls below a limit, or (3) both (1) and (2) and, if so, issues a warning signal in response, such as an audible sound or visual alarm. Systems which accomplish this notification or alarm function are known in the art and referred to earlier herein. 
         [0071]    In one embodiment, the cross-sectional area of passageway  54  in  FIG. 2  is less than the average cross-sectional area of the adult human mouth, held wide open. In one form of the invention, passageway  54  is approximately 22 millimeters as mentioned earlier. However, bite blocks of different sizes can be made for smaller persons, such as infants, or in larger sizes as well, as for large mouths or even for veterinary purposes. Also, more or fewer passageways  32 - 44  may be provided, and a bite block could be molded with, for example, multiple oxygen or fluid ports and multiple CO 2  or exhaust ports for monitoring purposes. Also, multiple ports could be provided for both delivering, for example, oxygen to the patient or for receiving CO 2  from the patient if desired. 
         [0072]    The bite block can, in one embodiment, comprise a phosphor, photoluminescent or “glow-in-the-dark” material incorporated into or integrally formed as a part of the bite block  10 . This is illustrated diagrammatically by the dots D in  FIG. 1 . In general, phosphor or photoluminescent materials are believed to absorb light, store energy obtained from the light, and then re-emit light over a period of time, in a process which is sometimes called “glowing in the dark.” The glow-in-the-dark bite block or bite block  10  can be useful because frequently the patient is present in a dimly lit room, such as an operating room in a hospital. The glow emitted by the luminescent bite block  10  provides assistance to medical technicians, such as providing a circular glowing target (wall  64 ) to facilitate inserting tubing or other apparatus into the mouth or throat of the patient. 
         [0073]    Although not shown, the bite block  10  could be made of any desired color and could be molded with or without the glow-in-the-dark material referred to earlier. 
         [0074]    It was stated that the monitoring system  20  in  FIG. 1  is used to measure carbon dioxide concentration. The monitoring system  20  may be selected to detect other fluids, such as gases other than CO 2 . 
         [0075]    Because the conduits  28 ,  34  and  36  in FIGS.  7  and  9 - 11  meet at a common area  50  or point, they can be said to be “Y-connected,” or “star-connected,” by analogy to the arms of the letter “Y,” the arms of a starfish, or the rays of an asterisk. A similar comment applies to conduits  32 ,  42  and  44 . 
         [0076]    It is pointed out that oxygen supply  16  in  FIG. 1  need not provide absolutely pure oxygen, but can supply other fluids, such as other gas mixtures. The patient breathes ambient atmospheric air through passageway  54  in  FIG. 2 . Other apparatus exist which a person may place into the mouth, which contain passages through which the person may breathe air. The mouthpiece of a SCUBA diving apparatus provides an example. However, the SCUBA mouthpiece does not deliver ambient atmospheric air. Similarly, aircraft pilots and astronauts may wear face masks which deliver breathable air, or oxygen. However, many of those masks do not deliver ambient atmospheric air, but air from a stored, pressurized source. Neither of these masks provide a system for diagnosing or diagnostic means or process, such as the monitoring system  20 . 
         [0077]    During use, the technician or doctor positions the bite block  10  in the mouth of the patient as illustrated in  FIGS. 1-2 . Before or after, the tubing  18  is connected to inlet port  12  and tubing  22  is connected to passageway  44  as shown in  FIG. 1 . The oxygen supply  16  and monitoring system  20  are activated. The monitoring system  20  generates information and may provide an audio or visual alarm or signal if no CO 2  exhale is detected. The technician or doctor may respond thereto by, among other things, changing the amount of oxygen supplied to the patient, changing an anesthesia or otherwise changing a course of care for the patient. 
         [0078]    Advantageously, the bite block  10  is unique in that it provides channel(s) or passageway(s) to supply oxygen to the patient, as well as a system to monitor patient&#39;s CO 2  level. The bite block  10  is attached to the oxygen supply  16  via the tubing  18 . The oxygen travels from the oxygen supply  16  through the tubing  18  and is delivered into the patient&#39;s nostrils and mouth M via the opening  50  at the top of the bite block  10  and the aperture  42  on the inside of the bite block  10 . When the patient exhales, the CO 2  enters the tube  22  attached to the opposite side of the bite block  10  via the nostril opening  44  at the area  50  as well as the aperture  42  on the inside of the bite block  10 , and the CO 2  is then monitored by the monitoring system  20 . The bite block  10  acts as a channel or manifold to deliver, channel or direct oxygen and CO 2 . Oxygen is supplied and the CO 2  level is monitored by the supply  16  and monitor  20 , respectively. The nurse or technician may then read and monitor the systems and care for the patient in response thereto. 
         [0079]    Note that, once the bite block  10  is inserted, the integral glow-in-the-dark material D may provide guidance to assist the doctor or technician to locate opening  54 , so that tubing, instruments, tools and the like may be inserted. 
         [0080]    In one form of the invention, the pressure of oxygen delivered to line  18  in  FIG. 1  is equal to that used in ordinary oxygen-assist systems, such as the ambulatory tanks used by people having lung impairment. 
         [0081]    Advantageously, the bite block  10  is an integral, one-piece molded construction that provides a manifold for direction both O 2  and CO 2  as described herein. 
         [0082]    While the process and product herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise process and product, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.