Abstract:
An airway device for use with deep sedation has a pair of conduits, one to supply oxygenated gas and the other to extract exhaled gas. The conduits are encompassed in a permeable sleeve with a stylet to facilitate positioning of the device in the airway.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Application No. 61/812,287 filed Apr. 16, 2013; the entire contents of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to methods and apparatus for facilitating surgical procedures performed under deep sedation. 
       BACKGROUND 
       [0003]    Most surgical procedures require some form of intervention to alleviate pain and/or discomfort and/or stress for the patient. Dental procedures such as dental operations are recognized as potentially highly stressful for the patient and this can be exacerbated when the patient is a younger person or child. In some situations, the stress induced by the procedure is sufficient to impair the ability of the dentist or dental surgeon to perform the procedure and may be sufficiently traumatic for the patient that further procedures will not be contemplated. 
         [0004]    To overcome the difficulties in performing the dental procedure, it is sometimes necessary to resort to the use of anesthetics for dental procedures, such as removing the wisdom teeth, or for patients who are highly stressed or to treat younger children. 
         [0005]    Deep sedation is now frequently performed in hospitals for out of operating procedures that are painful or require lack of movement. Deep sedation is also used in out of hospital settings which would include pediatric dental offices. Anesthetic machine (delivering anesthetic gases) is not needed for deep sedation anesthesia. However the monitoring would be similar for both—the difference being the lack of need to monitor inhaled and exhaled anesthetic gases for those patients receiving deep sedation. There is however a reticence to the use of deep sedation with dental procedures because of historical issues regarding substandard monitoring, inadequate training and distraction resulting from the dentist taking responsibility for the procedure and the anesthesia. 
         [0006]    The monitoring of the patient condition includes the maintenance of the level of oxygen in the blood and the continuous monitoring of the patients breathing. Monitoring of the patients breathing, includes monitoring the carbon dioxide exhaled by the patient. Nasal prongs are typically used for such monitoring, but with dental procedures they may be unreliable due to the fact that breathing may take place through the open mouth, the nasal passages or both. These concerns are exaggerated in children who have proportionally smaller nasal passages that may be partially occluded by adenoids or secretions. 
         [0007]    A further difficulty associated with the supply of oxygen and monitoring of the patient arises from the need to perform the procedure within the mouth so that there is a risk that the oxygen supply and carbon dioxide monitoring apparatus will impinge upon the area in which the dental surgeon may wish to work. 
         [0008]    It is therefore an object of the present invention to provide an apparatus and method in which the above disadvantages are obviated or mitigated. 
       SUMMARY OF THE INVENTION 
       [0009]    In general terms, the present invention provides an airway device having a pair of gas conduits, one to supply oxygen and the other to receive carbon dioxide. The conduits terminate within a porous sleeve and a malleable stylet allows positioning of the device to maintain the desired location of the sleeve. 
         [0010]    In the preferred embodiment, the sleeve is effective to distribute the oxygen within the airway of the patient and to receive carbon dioxide expelled by the patient. The sleeve spaces the conduits from the sidewall of the patient&#39;s oropharynx and avoids direct impingement of the oxygen supply with the surrounding wall and thereby avoids subcutaneous injection of the oxygen. 
         [0011]    In a further aspect there is provided a method of monitoring the condition of a patient during sedation by providing a supply of oxygen to the patient through a first conduit, monitoring carbon dioxide delivered through a second conduit, maintaining the first and second conduits in spaced relationship from the patients oropharynx by encompassing the conduits in a sleeve, and maintaining the position of the sleeve using a malleable stylet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Embodiments of the invention will now be described by way of an example only with reference to the accompanying drawings in which: 
           [0013]      FIG. 1  is a schematic representation of a patient undergoing a surgical procedure; 
           [0014]      FIG. 2  is a side view of a dental probe; 
           [0015]      FIG. 3  is a section of the probe of  FIG. 2 ; 
           [0016]      FIG. 4  is an end view of the probe of  FIG. 3 ; 
           [0017]      FIG. 5  is a view, similar to  FIG. 2 , of an alternative embodiment of probe; 
           [0018]      FIG. 6  is a view, similar to  FIG. 3 , of a still further embodiment of probe; 
           [0019]      FIG. 7  is an end view of the probe of  FIG. 6 ; and 
           [0020]      FIG. 8  is a view similar to  FIG. 1  of an alternative surgical procedure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring therefore to  FIG. 1 , a patient indicated at P is supported on a dental chair or operating table C to undergo a dental procedure. The patient P is sedated using an intravenous injection and an airway oxygenator  10  inserted into the patients mouth to monitor the patient&#39;s condition at the back of the mouth adjacent to the patients oropharynx. An oxygen supply  12  is connected to an airway oxygenator  10  to deliver oxygen to the patient and a carbon dioxide monitor  14  is connected to the probe to monitor the carbon dioxide levels in air expelled by the patient. 
         [0022]    As can best be seen in  FIGS. 2-4 , the airway oxygenator  10  has a pair of conduits  16 ,  18  that are connected respectively through the oxygen supply  12  and the CO 2  monitor  14 . The conduits  16 ,  18  are typically lumens made from a flexible plastics material and having an internal diameter in the order of 2 mm, capable of delivering an oxygen stream to the patient in the order of 1-3 litres per minute. 
         [0023]    The conduits  16 ,  18  terminate in a sleeve  20  so that the ends of the conduits  16   18  are enclosed by the sleeve. As can been in  FIG. 3 , the termination of the conduits  16 ,  18  are staggered in the longitudinal direction with the conduit  16  connected to the oxygen supply extending beyond the termination of the conduit  18  connected to the carbon dioxide monitor. The ends can be coterminous if preferred. 
         [0024]    The sleeve  20  is permeable and typically is formed from a porous soft material, such as an open cell foam to allow the free passage of gas through the sleeve. The sleeve  20  is sufficiently resilient to maintain a spacing between the conduits  16 ,  18  and the internal surface of the mouth or oropharynx. The sleeve  20  will typically have free body dimensions of 9 mm diameter and 25 mm length, and an internal diameter to receive snugly the conduits  16 ,  18 . The sleeve is secured to the conduits  16 ,  18 , by adhesive or laser welding to prevent separation in use. 
         [0025]    Located between the conduit  16 ,  18  is a stylet  22  that is bonded or connected to each of the conduits  16  over several inches, sufficient for the stylet to extend outside the mouth. The stylet  22  is a malleable material such as a wire formed from a biocompatible material and has sufficient bending stiffness to resist any bias exerted by the conduits  16 ,  18 . 
         [0026]    The stylet  22  and conduits  16 ,  18  are inter-connected as a unitary body over at least several inches to ensure compact placement within the patient. 
         [0027]    In Use, the oxygenator  10  is connected to the oxygen supply  12  and the CO 2  monitor  14  via the conduit  16 ,  18  and the sleeve  20  located on the terminal portion of the probe  10 . The oxygenator  10  may then be inserted into the patient&#39;s mouth and the malleable stylet  22  adjusted so that the sleeve  20  is located in the optimum position within the patients mouth. The stylet  22  maintains the conduit  16 ,  18  in the required position adjacent to the oropharynx and the sleeve  20  is effective to maintain the conduit  16 ,  18  in spaced relationship to the mouth of the patient. 
         [0028]    Oxygen delivered through the conduit  16 , permaeates through the sleeve  20  to be available for the patient, and the as expelled by the patient during normal breathing is collected in the conduit  18  and processed by the CO 2  monitor. The CO 2  monitor will ensure that there is an expected level of CO 2  in the collected gas which is used as an indication of satisfactory breathing of the patient. In the event that an abnormal level is noted, an alarm alerts the anesthesiologist to the adverse condition. 
         [0029]    The resilient material of the sleeve  20  prevents damage to the patients mouth and avoids direct contact of the oxygen conduit  16  with the patients to avoid subcutaneous injection of the oxygen. 
         [0030]    Upon completion of the dental procedure, the probe may simply be removed from the patient and discarded for hygienic reasons. 
         [0031]    If during the procedure it is necessary to reposition the probe, the stylet  22  may be reconfigured to move the probe into a different portion of the patient&#39;s mouth, allowing the surgeon to continue with the procedure. 
         [0032]    As shown in  FIG. 3 , the stylet  22  is formed as a single wire that is coextensive with and connected to each of the conduits  16 ,  18 . An alternative configuration is shown in  FIG. 5  in which like reference numerals will be used to denote like components with a suffix a added far clarity. In the embodiment of  FIG. 5 , the conduits  16   a,    18   a  are located within the sleeve  20   a  and a stylet  22   a  is wound about the pair of conduits in a generally helical configuration. The stylet contains the conduit within the confines of the helical winding and provides the necessary rigidity to maintain the conduits in the required location. In this manner, the stylet may be wound for varying extents along the conduits,  16 ,  18  to suite the particular operating environment. 
         [0033]    A further embodiment is shown in  FIGS. 6 and 7  where like components will be designated by a like reference number with a suffix b added for clarity. In the embodiment of  FIGS. 6 and 7 , the conduits  16 ,  18  are arranged coaxially with the conduit  16   b  extending beyond the termination of the conduit  18   b.  The stylet  22   b  may be connected to the outer surface of the conduit  18   b,  as shown above with respect to the embodiment of  FIGS. 2-4 , or may be wound about the outer body of the conduit  18   b  as shown above with respect to  FIG. 5 . 
         [0034]    As shown in  FIG. 8 , the airway oxygenator  10  may also be used with nasopharyngeal airways, indicated at N. The nasopharyngeal airways N are inserted into the nostril of the deeply sedated patient to provide a clear passage for the patient to breath, 
         [0035]    The airway oxygenator  10  is inserted in to the nasopharyngeal airway N and positioned adjacent the distal end of the nasopharyngeal airway. The airway oxygenator  10  is dimensioned to suit the nasopharyngeal airway. The sleeve  20  typically has a diameter of 3 mm and length of 20 mm for use with a 4-6 nasopharyngeal airway and Err diameter and 20 mm length when used with a 7-9 nasopharyngeal airway. 
         [0036]    In each case, the airway oxygenator does not completely occlude the nasopharyngeal airway and the porous sleeve allows flow along the airway as well as distribution of oxygen in to the region of the oropharynx. 
         [0037]    It will be seen from the above description that an airway oxygenator is provided in which oxygen is delivered to the required location without inhibiting access to the mouth and facial regions and carbon dioxide may be monitored during the surgical procedure. The provision of the porous sleeve  22  ensures diffusion of the oxygen supplied whilst maintaining the conduits  16 ,  18  in spaced relationship to the patient&#39;s oropharynx.