Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
   The present invention is related to and claims priority from now abandoned U.S. Provisional Patent Application Ser. No. 60/413,174, filed Sep. 24, 2002, incorporated by reference in its entirety. 

   FIELD OF THE INVENTION 
   The invention relates to establishing and maintaining an airway and, in particular, to an oropharyngeal device for establishing and maintaining an airway. 
   BACKGROUND OF THE INVENTION 
   The administration of anesthesia via a face mask technique usually requires continuous hands-on management. This is inconvenient during certain medical procedures that require access to the face because the face mask technique may obstruct access to the face. 
   For example, access to the face may be necessary for ophthalmologic examination, radiation therapy, MRIs (magnetic resonance imaging), and CT (computed tomography) or CAT (computed axial tomography) scans. If a mask is used to administer anesthesia during such procedures, access the patient&#39;s face may be hindered. Further, in such circumstances, anesthesiologists often use awkward hand positioning to allow access to the face which then requires repeated manipulation of the mask to ensure a patent airway. 
   The administration of anesthesia via a face mask technique is also inconvenient when the anesthesiologist must be distant from the patient such as during radiation therapy, CT or CAT scans, and during MRIs. Although the anesthesiologist may repeatedly instrument the trachea in such circumstances, the stimulation may result in irritation of the trachea especially when treatment is necessary on an on-going basis. For example, during radiation therapy, patients may be repeatedly treated each day over a period of several weeks. Repeated instrumentation during this on-going treatment will irritate the patient&#39;s trachea and may result in other adverse consequences such as a sore throat and loss of appetite due to the irritated trachea and hypopharynx. 
   The above situations are conventionally resolved by using general anesthesia with endotracheal intubation, by using intravenous techniques without securing the airway with adjunctive devices, by using a laryngeal mask airway (LMA), or by using a cuffed oropharyngeal airway (COPA). Each of these solutions has its respective drawbacks especially during procedures such as radiation treatment where deep anesthetization is not necessary, where the patient breathes by himself, and where treatment is on an on-going basis. 
   An endotracheal tube may be used to deliver anesthetic gases and to maintain a patient&#39;s airway. Endotracheal intubation is very stimulating because the endotracheal tube extends through the vocal chords and into the trachea. This requires that the patient be deeply anesthetized or partially paralyzed with neuromuscular blocking agents to keep him from reaction to the intubation. Thus, endotracheal intubation is not desirable for circumstances that do not require deep anesthetization. Endotracheal intubation also subjects the patient to laryngoscopy for inserting the endotracheal tube and to tracheal irritation which makes it undesirable for circumstances requiring repeated instrumentation. Generally, endotracheal intubation is better suited for more invasive procedures when the patient is deeply anesthetized and not responsive to the stimulation caused by the endotracheal tube and can not breathe on his own. 
   Intravenous techniques may obviate the use of inhalational agents, but still necessitate maintenance of a patent airway. Moreover, end-tidal carbon dioxide monitoring may be desirable in addition to supplemental oxygen during total intravenous anesthesia. Further, suction catheters must be introduced to suction secretions from the patient&#39;s pharynx. 
   An LMA may be used to provide oxygen to a patient and to monitor end-tidal carbon dioxide and is less invasive than an endotracheal tube because it does not go through the patient&#39;s vocal chords. However, the LMA must be connected to a conventional anesthesia circuit, does not provide a mechanism for suctioning secretions, and requires technical facility for its insertion that may require adjunctive equipment for its application. Further, the LMA is very stimulating because it includes a cuff that inflates in the patient&#39;s trachea to prevent reflux from the stomach from entering the trachea. This stimulation is undesirable in circumstances requiring repeated instrumentation. 
   A COPA is a device consisting of an airway with a cuff. A COPA device may be used to provide oxygen to a patient and to monitor end-tidal carbon dioxide. However, the COPA must be connected to a conventional anesthesia circuit or to an adapter to connect the COPA to an oxygen source and may cause the patient discomfort due to the inflated cuff. Further, the COPA does not include a suctioning mechanism which may result in a medical procedure being interrupted in order for an anesthesiologist to suction the patient when secretions are building up. 
   For the administration of anesthesia, there is a need for a device that will maintain a patent airway while providing the capability to oxygenate the patient, to provide suctioning, and to monitor end-tidal carbon dioxide. Further, there is a need for such a device that is minimally stimulating to allow for repeated use during on-going treatments, that does not block access to the face of a patient, and that allows an anesthesiologist to be distant from the patient. 
   SUMMARY OF THE INVENTION 
   The invention provides an oropharyngeal device for insertion into the mouth of a patient. The device includes a body having a distal end and a proximal end. The device body is sized such that when the distal end of the body is inserted into the mouth of the patient until the proximal end is disposed outside and adjacent to the patient&#39;s mouth, the distal end is disposed within the pharynx above the epiglottis. At least one channel extends between the proximal end and the distal end of the device body to form at least one airway in the device body. Inhalant gas may be conveyed to the patient via at least one first conduit that extends from the proximal end to the distal end of the device body. Suctioning may be applied via at least one second conduit that extends from the proximal end to the distal end of the device body. End-tidal carbon dioxide of gas exhaled by the patient may be monitored via at least one third conduit that extends from the proximal end of the device body and terminates at a position within the channel. 
   The invention also provides a method of establishing and maintaining an airway of a patient. The oropharyngeal device described above is inserted into the mouth of the patient until the proximal end is outside and adjacent to the patient&#39;s mouth. An inhalant gas source, a suctioning device, and a gas sampling device are connected to the first, second, and third conduits, respectively. 
   For purposes of illustrating the invention, the distal end of the device shall refer to the end which penetrates into the patient&#39;s airway (marked  106  in  FIG. 1 and 206  in  FIG. 2 ). The proximal end shall refer to the end which is held adjacent to the mouth (marked  104  in  FIG. 1 and 204  in  FIG. 2 ). The terms “proximal” and “distal” with respect to orientation and direction in the patient&#39;s airway shall mean, respectively, the directions toward and away from the patient&#39;s mouth. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown. 
       FIG. 1A  is an isometric view of an oropharyngeal device according to the present invention; 
       FIG. 1B  is a cross-sectional view of the oropharyngeal device shown in  FIG. 1A  taken along line  1 B- 1 B; 
       FIG. 1C  is a cross-sectional view of the oropharyngeal device shown in  FIG. 1A  taken along line  1 C- 1 C; 
       FIG. 1D  is a cross-sectional view of the oropharyngeal device shown in  FIG. 1A  taken along line  1 D- 1 D; 
       FIG. 1E  is a sagittal view of a patient showing the oropharyngeal device of  FIG. 1A  inserted into the mouth of the patient; 
       FIG. 2A  is a front isometric view of an oropharyngeal device according to the present invention; 
       FIG. 2B  is a rear isometric view of the oropharyngeal device shown in  FIG. 2A ; 
       FIG. 2C  is a front view of the proximal end of the oropharyngeal device shown in  FIG. 2A  without the conduits extending from the proximal end of the device; 
       FIG. 2D  is a sagittal view of a patient showing the oropharyngeal device of  FIG. 2A  inserted into the mouth of the patient; 
       FIGS. 3A-3C  are three cross-sectional views of the oropharyngeal device shown in  FIG. 2A  taken along line  3 - 3  in  FIG. 2A  illustrating three different lengths of the third conduit; 
       FIG. 4A  is an isometric view of an oropharyngeal device according to the present invention; 
       FIG. 4B  is a cross-sectional view of the oropharyngeal device shown in  FIG. 4A  taken along line  4 B- 4 B; 
       FIG. 4C  is a front view of the proximal end of the oropharyngeal device shown in  FIG. 4A  without the conduits extending from the proximal end of the device; 
       FIG. 5A  is an isometric view of an oropharyngeal device according to the present invention; 
       FIG. 5B  is a cross-sectional view of the oropharyngeal device shown in  FIG. 5A  taken along line  5 B- 5 B; 
       FIG. 6A  is an isometric view of an oropharyngeal device according to the present invention; 
       FIG. 6B  is a front view of the proximal end of the oropharyngeal device shown in  FIG. 6A ; and 
       FIG. 6C  is a cross-sectional view of the oropharyngeal device shown in  FIG. 6A  taken along line  6 C- 6 C. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings in which like reference numerals indicate like elements, there is shown in  FIGS. 1A-E  an oropharyngeal device  100  according to an exemplary embodiment of the present invention. The device  100  includes a body  102  having a proximal end  104  and a distal end  106 . 
   A channel  108  forms an airway through the body  102  that extends through the body  102  from its proximal end  104  to its distal end  106 . As illustrated in  FIG. 1E , the body  102  is sized such that when the distal end  106  of the body  102  is inserted into the mouth  152  of a patient  150  until the proximal end  104  is disposed outside and adjacent to the patient&#39;s mouth  152 , the distal end  106  of the body  102  is disposed within the pharynx  154  above the epiglottis  156 . The body  102  may be formed of a rigid material to serve as a bite block to prevent the patient from biting any conduits inserted through the channel. 
   The airway channel may be completely enclosed within the body of the oropharyngeal device, as illustrated by channel  108 , such that the airway channel has a closed cross section. Alternatively, one or more channels may be formed by a ridge, flange or protrusion running the length of the body, as illustrated by channels  508  and  509  in  FIGS. 5A and 5B . 
   The device  100  includes three conduits  110 ,  112 ,  114  that may be used during the administration of anesthesia. The first conduit  110  is for conveying an inhaling gas to the patient  150 . Conduit  110  extends from the proximal end  104  to the distal end  106  of the body  102 . The second conduit  112  is for suctioning. It also extends from the proximal end  104  to the distal end  106  of the body  102 . The third conduit  114  is for sampling gas exhaled by the patient  150 . Conduit  114  extends in the channel  108  from the proximal end  104  of the body  102  and terminates at a position  116  in the channel  108 . Conduit  114  extends to a position  116  within the channel  108  that corresponds to the location of the mouth of the patient  150 , when the device is inserted. 
   Although the body  102  is illustrated in  FIGS. 1A-E  as having a rectangular closed cross-section, the body  102  may alternatively be formed in other shapes including a body having an oval, round or square-section. The channel  108  is also illustrated in  FIGS. 1A-E  as having a rectangular cross-section and may also be formed in other shapes, not necessarily the same shape as the body  102 . Similarly, although the first, second, and third conduits  110 ,  112 ,  114  are illustrated as having round cross-sections, they too may be independently formed in other shapes. 
   In the embodiment illustrated in  FIGS. 1A-E , the first and second conduits  110 ,  112 , are formed within the body  102  and the third conduit  114  is formed within the channel  108 . Alternatively, each conduit  110 ,  112 ,  114  may be formed either within the body  102 , within the channel  108 , or partially within the body  102  and partially within the channel  108 . The first, second and third conduits each may have an internal diameter between 2 mm and 5 mm. 
   A further embodiment of the oropharyngeal device of the invention is shown in  FIGS. 2A-2D . The oropharyngeal device  200  includes a flange  220  at the proximal end  204  of the body  202 . As illustrated in  FIG. 2D , the distal end  206  of the body  202  is inserted into the mouth of a patient  250  such that the proximal end  204  of the body  202  is outside and adjacent to the patient&#39;s mouth  252 . The flange  220  abuts the entrance of the patient&#39;s mouth and serves to prevent the oropharyngeal device  200  from further proceeding into the patient&#39;s mouth. 
   In certain embodiments of the invention, the third conduit  214  (for sampling patient exhaled gas) is contained in channel  208 . In such embodiments, the third conduit  214  may terminate at various positions within the channel  208 .  FIGS. 3A-C  are cross-sectional views of the oropharyngeal device  200  taken along line  3 - 3  in  FIG. 2A  which illustrate various positions within the channel  208  at which the third conduit  214  may terminate. Although end-tidal carbon dioxide is optimally monitored at the distal end  206  of the device body, a third conduit  214  having its distal end positioned at or terminating at the distal end  206  of the device body may be clogged by secretions. In  FIG. 3A , the third conduit  214   a  extends from the proximal end  204  of the body  202  to a position  316   a  within the channel  208  located in the middle-third  302  of the body  202 . In this central position  302 , the third conduit  214   a  terminates at a position distant from the proximal end  204  for better gas sampling and at a position distant from the distal end  206  to avoid clogging. The third conduit  214   b  shown in  FIG. 3B  extends from the proximal end  204  of the body  202  to a position  316   b  within the channel  208  located within the first-third  301  of the body  202  as measured from the proximal end  204 . The third conduit  214   c  shown in  FIG. 3C  extends from the proximal end  204  of the body  202   a  to a position  316   c  within the channel  208  located in the farthest-third  303  of the body  202  as measured from its proximal end  204 . 
   The oropharyngeal device may include more than three conduits, where more than one inhalant gas conduit, suctioning conduit, or exhalation gas sampling conduit is present. The oropharyngeal device  400  shown in  FIGS. 4A-C  includes two conduits  410 ,  411  for administering an inhalant gas which may be used, for example, to separately administer two different inhalant gases or to administer a larger volume of a single inhalant gas. The oropharyngeal device  400  includes two conduits  414 ,  415  for sampling exhalant gas which may each be coupled, for example, to a different device for sampling different components of the exhalant gas. Alternatively, the second conduits  414 ,  415  may be used in a redundant fashion where one serves as the active conduit and the other serves as the standby conduit. In the event that the active conduit ceases to function as a result of clogging, for example, the standby conduit may instead be used to sample the exhalant gases. 
   As illustrated in  FIG. 4B , the conduit  414  for sampling exhalant gases extends entirely within the channel  408  from the proximal end  404  of the body  402  to a position  416  where it terminates within the channel  408 . The other conduit  415  for sampling exhalant gases is formed within the body  402  and extends from the proximal end  404  of the body  402  and terminates at a position  418  within the channel  408 . 
   The present invention may be applied to oropharyngeal devices having bodies of various shapes. For example, the oropharyngeal device  500  shown in  FIG. 5A  includes two U-shaped channels  508 ,  509  formed within a body  502  having an I-shaped cross-section. 
   The oropharyngeal device  500  includes a first conduit  510  for administrating an inhalant gas that extends through the body  502  from its proximal end  504  to its distal end  506 . A second conduit  512  for suctioning also extends through the body  502  from its proximal end  504  to its distal end  506 . A third conduit  514  for sampling exhalant gases is formed adjacent to a sidewall  520  of the channel  509  and extends from the proximal end  504  of the body  502  to a position  516  within the channel  509 . 
   To facilitate connection and disconnection of conventional devices such as inhalant gas sources, gas sampling devices, and suctioning devices to the conduits of an oropharyngeal device according to the present invention, the oropharyngeal device may include standard connectors for connecting to such devices. The connectors may be connected to the first, second, and third conduits at the proximal end of the body. Alternatively, as shown in  FIGS. 6A-C , the oropharyngeal device  600  may include flexible hoses,  632 ,  634 ,  636  coupled to the ends of the first, second, and third conduits  610 ,  612 ,  614 , respectively, at the proximal end  604  of the body  602 . The ends of the flexible hoses  632 ,  634 ,  636  may include connectors  638 ,  640 ,  642 . 
   During some medical procedures the mouth of the patient may be covered and it may be desirable for the hoses  632 ,  634 ,  636  or connections to other devices be coupled to the oropharyngeal device  600  from the side. In such cases, a right-angle connector  644  may be used to connect a conduit  612  to the hose  634 . Alternatively, instead of the conduits  610 ,  612 ,  614  extending to the proximal end  604  of the body  602 , the conduits may exit a side of the body  602  adjacent to the proximal end  604  or may exit through the side of the flange. 
   An oropharyngeal device according to the present invention allows for maintenance of an airway while simultaneously administering an inhalant gas, suctioning, and sampling an exhalant gas. This is possible without obstructing access to the face of a patient because first, second, and third conduits for each purpose are integrated into the device. This facilitates the administration of anesthesia during treatment of a patient&#39;s head or neck despite lack of or obstructed access to the patient&#39;s mouth, face, or airway. In the event that mechanical ventilation or “positive pressure” is required to augment a patient&#39;s breathing while an oropharyngeal device according to the present invention is in use, a mask for providing mechanical ventilation may be applied over the device and the patient&#39;s mouth. 
   The oropharyngeal device is sized to terminate above or proximal to the path of travel of the epiglottis and avoids manipulation of the larynx and subglottic structures. This avoids increased stimulation and avoids medical complications associated with devices which may impinge on or cause damage to the delicate laryngeal and supra-laryngeal structures and makes the oropharyngeal device suitable for circumstances requiring repeated use such as during on-going radiation treatment. A patient may be taken to a recovery area with the oropharyngeal device still in position and it can then be easily removed as the patient awakens, with very little discomfort to the mouth or throat. 
   The oropharyngeal device may be inserted in a similar fashion to conventional oropharyngeal airways and thus is simple to apply, does not require extensive training or instruction to use, and does not require any special or additional equipment such as an anesthesia circuit. Further, the device is recognizable as an anesthesia device and will be readily acceptable to anesthesia personnel. The device may be used to assist in the placement of an endotracheal tube by inserting a fiber optic scope device in the channel for placing the endotracheal device through or adjacent to the oropharyngeal device. 
   All documents referred to herein are incorporated by reference. While the present invention has been described in connection with the preferred embodiments and the various figures, it is to be understood that other similar embodiments may be used or modifications and additions made to the described embodiments for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather should be construed in breadth and scope in accordance with the recitation of the appended claims.

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