Patent Publication Number: US-2016228035-A1

Title: Naso-oral device

Description:
The present invention relates to a naso-oral device for use in medical procedures such as endoscopy. The device facilitates the administration of gas (generally comprising oxygen) to a patient, and the sampling of exhaled gas. 
     EP 1 659 939 discloses an endoscopic mouthguard consisting of a bite block releasably coupled to a gas distribution manifold. The bite block has an annular body, like a napkin ring, with a peripheral flange at one end. In use the annular body is passed into a patient&#39;s mouth until the flange abuts around the mouth. A gas delivery passage is formed in the flange. It extends upwardly to an inlet opening and downwardly and inwardly to an outlet within the bore of the annular body. The gas distribution manifold is a small chamber, adapted to fit on top of the bite block, just under the patient&#39;s nose. It has a gas inlet tube. There are one or more upper outlet openings for passing gas to the patient&#39;s nostrils, and a back outlet for passing gas into the gas delivery passage in the bite block&#39;s flange, for passage through the annular body, into the patient&#39;s mouth. 
     In a commercial product embodying the patented invention (the TwinGuard (trademark) device of Trawax Pty Ltd), the bite block is adapted to be coupled to a CO 2  monitoring assembly for sampling CO 2  in exhaled air from the patient&#39;s nose and mouth. For this purpose, a nasal sampler is passed into one nostril. 
     The assembly is typically used while the patient is undergoing endoscopy, endoscopic apparatus being passed in and out through the annular body. After the procedure has finished, it may still be desired to administer gas to the patient. The bite block is uncoupled from the gas distribution manifold, and removed from the patient&#39;s mouth. The manifold remains adjacent the patient&#39;s nose and can continue to supply gas. 
     Broadly, the invention provides an endoscopic bite block system for oxygen delivery and carbon dioxide monitoring, the bite block system comprising: 
     a bite block for positioning at least partially within a human mouth, the bite block comprising an endoscope channel sized to enable an endoscope to pass therethrough; and 
     a nasal cannula detachably connected to the bite block, the nasal cannula comprising: 
     a delivery portion comprising a nasal outlet port to provide oxygen to a human nostril and an oral outlet port to provide oxygen to a human mouth, the oral outlet port positioned opposite the nasal outlet port; and 
     a monitoring portion comprising a nasal tube terminating at a nasal in port to sample air expelled from a human nostril. It may include: 
     a nasal sampling line in fluid communication with a main sampling line and the nasal tube of the monitoring portion of the nasal cannula; and 
     an oral sampling line in fluid communication with the main sampling line and an oral sampling channel of the bite block, wherein the oral sampling line comprises a valve. The oral sampling line may comprise a connector enabling the oral sampling line to be separated into at least two pieces. Desirably the valve is part of the connector, and the valve automatically closes upon separating the oral sampling line into the at least two pieces. The connector may comprise a Luer connector. 
     There is preferably a main delivery line connected to an inlet port of the delivery portion to provide oxygen to the delivery portion, the main delivery line being monolithically attached to the main sampling line along a length of the main delivery and sampling lines. 
     The delivery portion and monitoring portion may form a unitary structure. 
     The delivery portion may have a second nasal outlet port, the nasal outlet ports being separated by a distance that enables the outlet ports to each be positioned beneath a different nostril. 
     The monitoring portion may include a second nasal tube terminating at a second nasal inlet port to sample air expelled from a second human nostril, the nasal tubes separated by a distance that enables the nasal tubes to each be positioned within a different nostril. 
     The oral outlet port may be positioned at an end of an oral delivery channel extending in a direction opposite the nasal outlet port. 
     The nasal cannula may be detachably connected to the bite block by the oral delivery channel being positioned within a cavity of the bite block, the cavity of the bite block in fluid communication with at least one oral outlet channel of the bite block, the at least one oral outlet channel positioned within the endoscope channel. 
     The bite block may have an outer surface extending around the endoscope channel, the outer surface having a first durometer (hardness); and 
     an elastomeric layer overmolded on at least a portion of the outer surface, the elastomeric layer having a second durometer, which is softer than the first durometer. 
     The nasal and oral sampling lines preferably comprise tubing having a channeled inner lumen to resist kinks and occlusion. 
     According to a preferred class of embodiment of the present invention there is provided a naso-oral device comprising an annular bite block and a gas manifold, wherein the gas manifold is releasably engageable with the bite block to communicate with a gas supply path through the block for supplying gas to a patient&#39;s mouth; the gas manifold also including a nasal supply passage for supplying gas to a patient&#39;s nose; the device also having a first CO 2  monitoring line connected to a central region of the bite block for monitoring orally exhaled gas; and a second CO 2  monitoring line connected to the gas manifold for monitoring nasally exhaled gas; wherein the gas manifold can be disconnected from the bite block and used to supply gas and to monitor exhaled gas. 
    
    
     
       An embodiment of the invention will be described with reference to the accompanying drawings in which: 
         FIG. 1  is a front perspective view of a naso-oral assembly comprising a device embodying the invention; and 
         FIG. 2  is a rear perspective view showing the bite block and nasal cannula assembled together. 
     
    
    
     The illustrated assembly  10  includes a bite block  12  and a gas manifold (or nasal cannula)  14 . The bite block  12  comprises a unitary plastics moulding. A tubular body portion  16  has a rounded rectangular cross-section and slightly increases in diameter from front to rear. At the rear it terminates with a peripheral rim  18 . At the bottom there is a recessed area  20  for accommodating a patient&#39;s tongue. The external surface of the body portion  16  has an overmolding  22  of softer, rubbery plastic, engageable more comfortably and safely by a patient&#39;s teeth. 
     At the front of the body portion  16  it is surrounded by a peripheral flange portion  24 . There is a smooth transition from the front of the flange portion  24  to the interior of the tubular body portion  16 , for guiding objects that are to be passed in through the body portion  16 . As viewed from the front, the opening  26  of the body portion  16  is wide and uncluttered. 
     The central upper region of the flange portion  24  defines a gas passage  28  extending downwardly from a laterally elongate upper opening  30 . At the bottom, the passage  28  turns inwardly, the final section being within the tubular body portion  16 , defined between the upper surface  32  of the body portion and a U-shaped projecting flange  34  that extends parallel to that surface a short distance below it, terminating a little in front of the recessed area  20 . The flange  34  is connected to the upper surface  32  by two webs  36  that define a central conduit  38  and two side passages  40 . The central conduit  38  leads to a front opening  42  where a monitor tube  44  is connected. The side passages  40  join the main gas passage  28 . In the front wall of the gas passage  28 , there is a small opening  46 . 
     A-shaped limbs  48  extend on each side of the peripheral flange portion  24  for attachment of a strap  50 . Adjacent to the flange portion  24 , there are several grooves  52  constituting living hinges, to facilitate flexing of the limbs  48 . 
     The gas manifold or nasal cannula  14  has a front portion which is a gas conduit  54 . It is a tubular body, open at the bottom. Its top surface, provided by a top plate portion  56 , is laterally arcuate, rising from the centre. The top plate portion  56  has an opening  58  at each lateral end. The spacing of the openings  58  is similar to the typical spacing of human nostrils. There are short internal partitions such that the openings  58  lead into respective tubular conduits extending about half way down the body  54 . A lateral port  59  opens into one of the tubular conduits and is coupled to an oxygen supply line  60 . The front face of the body  54  has a raised nib  62 . The body is formed of flexible plastics material, dimensioned so that it can be pushed into the gas passage  28  in the bite block  12 , through the opening, resiliently deforming the body  54  to allow passage of the nib  62  until this can project through the small opening  46  in the front wall of the gas passage  28 . The gas manifold  14  is then securely, but releasably, coupled to the bite block  12 , in a precise location. 
     The gas manifold  14  also has a rear portion which is a monitoring chamber  64 . This has a laterally-extending tubular body  66 , closed at one end  68  and having a port  70  at the other end, coupled to a CO 2  monitoring line  72 . 
     Two narrow tubular extensions  74  rise up from the body  66  for about 1 cm, curving slightly to the rear. They terminate in smooth apertures  76 . They are very soft and flexible, so they can be passed into a patent&#39;s nostrils without risk of injury or discomfort. 
     A main monitoring line  78  extends from a connector  80  (for connection to a gas monitor) to a branch unit  82  from which the two monitoring lines  44 , 72  extend. The branch unit  82  is designed so that the line  44  leading to the front opening  42  of the bite block  12  can be uncoupled, and the unit  82  seals the inlet from which the line  44  was uncoupled. Communication along the other monitoring line  72  is unaffected. 
     In use, the assembly as shown in  FIG. 1  is coupled to an oxygen source and a CO 2  monitor. The body portion  16  of the bite block  12  is passed into a patient&#39;s mouth, and the tubular extensions  74  are carefully positioned to extend into the patient&#39;s nostrils. The assembly is held in place by means of the straps. The patient can now breathe in supplied oxygen by mouth and/or through the nostrils. The CO 2  content of gas exhaled through either mouth or nostrils can be monitored. An endoscopic procedure can be carried out, endoscopy probes etc. being fed through the tubular body portion  16  of the bite block. 
     After the procedure has finished, the bite block  12  is removed. The nasal cannula  14  is separated from the bite block  12 . The bite block&#39;s monitoring line  44  is separated from the branch unit  82 . The nasal cannula  14  is then re-mounted adjacent the patient&#39;s nose so it can continue to supply oxygen (to the nose via the tubular extensions  74 , and to the mouth, through the opening at the bottom of the tubular body  66 ), and to monitor exhaled gas.