Patent Publication Number: US-2013233311-A1

Title: Airway assembly and methods of using an airway assembly

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/966,767, filed Dec. 28, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 10/569,397 filed on Nov. 13, 2006, all hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     Embodiments described herein generally relate to an airway assembly and methods of using an airway assembly. More specifically, embodiments described herein relate to devices for endotracheal intubation and methods of performing endotracheal intubation. Tracheal intubation is a common and routine procedure for restoring or for maintaining the air passageway to ventilate the lungs by allowing for externally applied or artificial respiration when the patient is unable to breath. Endotracheal intubation is a procedure by which an endotracheal tube is inserted through the mouth into the trachea. Before surgery, this is often done under deep sedation. In emergency situations, the patient is often unconscious at the time of this procedure. Often, endotracheal intubation is used when patients are critically ill and cannot maintain adequate respiratory function to meet their needs. 
     Conventional endotracheal tubes consist generally of a semi-rigid flexible plastic tube having a beveled distal end, a ventilator connector at a proximal end for connecting an external ventilator to the endotracheal tube, a dilatable balloon positioned proximate the distal end of the tube and, coupled to an outer wall surface of the tube, an inflation tube or lumen associated with the tube wall that communicates air to the balloon to inflate the balloon and seat the balloon, and, hence, the tube, within the trachea and seal the trachea to prevent backflow of air. 
     Usually, an endotracheal tube is inserted using a laryngoscope that permits visualization of the vocal cords and the upper portion of the trachea and retracts the tongue during intubation. Proper intubation is critical in order to ventilate the lungs. If the tube is inadvertently placed in the esophagus, adequate lung ventilation will not occur, with possible concomitant neural injury, cardiac arrest or death. Aspiration of stomach contents can result in pneumonia and acute respiratory distress syndrome. Placement of the tube too deep can result in only one lung being ventilated and can result in a pneumothorax as well as inadequate ventilation. During endotracheal tube placement, damage can occur to the teeth, to the soft tissues in the back of the throat, as well as to the vocal cords. 
     Assuming that an endotracheal tube is placed properly and is secured within the trachea by an inflated balloon, the endotracheal tube provides a good air passageway to ventilate the lungs, however, having an endotracheal tube residing within the trachea implies several changes to the patient&#39;s airways. An important change when a patient is intubated is that the airway passages loses sterility and becomes colonized within a few hours of starting mechanical ventilation with a risk of ventilator associated pneumonia—around 8% to 28% of patients admitted in the intensive care unit. The risk for developing pneumonia has been clinically demonstrated to be associated with the current endotracheal tubes. Pneumonia is often the result of aspiration during intubation secondary to the large size of the endotracheal tubes being introduced through the narrow vocal cord space, contaminated secretions pooling above the endotracheal tube cuff or secretions leaking around the cuff. Leakage around an endotracheal cuff is commonly associated with a decreased pressure inside the cuff which occurs a few hours post-inflation and the resultant formation of creases or channels in the partially deflated cuff that allow contaminated secretions to pass into the more distal bronchial passages. Finally, pneumonia may occur due to decreased clearance of mucus produced by the lungs. Decreased mucus clearance frequently occurs in patients requiring mechanical ventilation due to the position of the tube in the middle of the trachea such that distal secretions are not removed by patient coughing but are only removed by a suction catheter advanced into the distal bronchial passages through the endotracheal tube. There are other drawbacks presented by currently available endotracheal tubes, specially related to the pressure transmitted from the cuff to the tracheal mucosa. This has been associated with post-intubation tracheal narrowing or stenosis which is a very serious complication with devastating implications for patients and requiring a very complex surgical management that is performed in few specialized centers. Accordingly, it is desirable to improve endotracheal tubes. 
     SUMMARY 
     Many embodiments of an airway assembly and methods of using an airway assembly are disclosed. In one embodiment, an airway assembly includes an outer tube, an inner tube disposed coaxially and reciprocally moveable within the outer tube, and a seal disposed on the inner tube. The seal is diametrically movable between a collapsed position in which the seal is constrained by the outer tube and an expanded position where the seal is released from the outer tube and engages an airway, such as a tracheal or a bronchial passage. 
     Another embodiment is an airway assembly that includes an outer tube having a proximal portion and a distal portion, and an inner tube disposed coaxially and reciprocally moveable within the outer tube. The inner tube has a proximal portion and a distal portion. The proximal portion of the outer tube has an outer diameter that is larger than an outer diameter of the distal portion of the outer tube. The proximal portion of the inner tube has an outer diameter that is larger than an outer diameter of the distal portion of the inner tube. 
     A further embodiment provides a method of using an airway assembly in an airway. The method comprises the steps of: providing an airway assembly having an outer tube, an inner tube disposed coaxially and reciprocally movable within the outer tube, and a diametrically expandable seal disposed on the inner tube. The seal is inserted into the airway. The seal is moved from a constrained collapsed position to an expanded position where the seal engages the airway. Fluid is moved through the inner tube and the seal. 
     An additional embodiment provides a method of using an airway assembly in an airway. The method comprises the steps of: providing an airway assembly having an outer tube, and an inner tube disposed coaxially and reciprocally moveable within the outer tube. The airway assembly is placed in a first status. The airway assembly is inserted into an airway when the airway assembly is in the first status. The outer tube is moved with respect to the inner tube to place the airway assembly in a second status. The outer tube is moved with respect to the inner tube to place the airway assembly in a third status. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an airway assembly described herein in a collapsed configuration; 
         FIG. 2  is a side-elevational sectional view of the airway assembly of  FIG. 1 ; 
         FIG. 3  is a perspective view of an airway assembly of  FIG. 1  in an expanded configuration; 
         FIG. 4  is a side-elevational sectional view of the airway assembly of  FIG. 3 ; 
         FIG. 5  is an enlarged view of a portion of the airway assembly of  FIG. 3 ; 
         FIG. 6  is an elevational view of portions of the airway assembly of  FIG. 3 ; 
         FIG. 7  is an end view, taken along line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a perspective view of an airway assembly described herein in a collapsed configuration; 
         FIG. 9  is a side-elevational sectional view of the airway assembly of  FIG. 8 ; 
         FIG. 10  is a perspective view of the airway assembly of  FIG. 8  in an expanded configuration; 
         FIG. 11  is a side-elevational sectional view of the airway assembly of  FIG. 10 ; 
         FIG. 12  is an enlarged view of a portion of the airway assembly of  FIG. 10 ; 
         FIG. 13  is an side-elevational view of a portion of the airway assembly of  FIG. 12 ; 
         FIG. 14  is an end view, taken along line  14 - 14  of  FIG. 13 ; 
         FIG. 15  is a perspective view of an airway assembly described herein in a collapsed configuration; 
         FIG. 16  is a side-elevational sectional view of the airway assembly of  FIG. 15 ; 
         FIG. 17  is a perspective view of the airway assembly of  FIG. 15  in an expanded configuration; 
         FIG. 18  is a side-elevational sectional view of the airway assembly of  FIG. 17 ; 
         FIG. 19  is an enlarged view of a portion of the airway assembly of  FIG. 17 ; 
         FIG. 20  is an elevational view of a portion of the airway assembly of  FIG. 19 ; 
         FIG. 21  is an end view taken along line  21 - 21  of  FIG. 20 ; 
         FIG. 22  is a perspective view of an airway assembly described herein in a collapsed configuration; 
         FIG. 23  is a side-elevational sectional view of the airway assembly of  FIG. 22 ; 
         FIG. 24  is a perspective view of the airway assembly of  FIG. 22  in an expanded configuration; 
         FIG. 25  is a side-elevational sectional view of the airway assembly of  FIG. 24 ; 
         FIG. 26  is an enlarged view of a portion of the airway assembly of  FIG. 24 ; 
         FIG. 27  is an end view taken along line  27 - 27  of  FIG. 28 ; 
         FIG. 28  is an elevational view of a portion of the airway assembly of  FIG. 26 ; 
         FIG. 29  is a perspective view of an airway assembly described herein in a collapsed configuration; 
         FIG. 30  is a side-elevational sectional view of the airway assembly of  FIG. 29 ; 
         FIG. 31  is a perspective view of the airway assembly of  FIG. 29  in an expanded configuration; 
         FIG. 32  is a side-elevational sectional view of the airway assembly of  FIG. 31 ; 
         FIG. 33  is an enlarged view of a portion of the airway assembly of  FIG. 31 ; 
         FIG. 34  is an elevational view of a portion of the airway assembly of  FIG. 31 ; 
         FIG. 35  is an end view taken along line  35 - 35  of  FIG. 34 ; 
         FIG. 36  is a diagrammatic view of a portion of an airway assembly described herein used with a patient; 
         FIG. 37  is a diagrammatic view of a portion the airway assembly of  FIG. 36  located within a patient; 
         FIG. 37A  is a diagrammatic view of an embodiment of the airway assembly described herein; 
         FIG. 38  is a diagrammatic view of a portion the airway assembly of  FIG. 36  located within a patient; 
         FIG. 39  is a diagrammatic view of a portion of an airway assembly described herein used with a patient; 
         FIG. 40  is a diagrammatic view of a portion the airway assembly of  FIG. 36  located within a patient; 
         FIG. 41  is a diagrammatic view of a portion of an airway assembly described herein used with a patient; 
         FIG. 42  is a diagrammatic view of a portion the airway assembly of  FIG. 36  located within a patient; 
         FIG. 43  is a diagrammatic view of a portion of an airway assembly described herein used with a patient; 
         FIG. 44  is a diagrammatic view of a portion the airway assembly of  FIG. 36  located within a patient; and 
         FIG. 45  is a diagrammatic view of a portion of an airway assembly described herein used with a patient. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments described here relate generally to an airway assembly  10 . The airway assembly  10  can be used to intubate a patient. Structures common to the embodiments are provided with like reference numerals. As the embodiments are related, features, such as dimensions, materials and the like, may be shared. Differences among the embodiments are highlighted when present. Both structures of and methods of use of the embodiments are described below. Some features of the embodiments may become clear after consideration of the entirety of this description. 
     One embodiment of an airway assembly  10  is shown in  FIG. 1 . This embodiment is similar to the airway assembly disclosed in co-pending PCT patent application International Publication Number WO 2005/018713 which is assigned to the assignee of the present case. The disclosure of that PCT patent application is incorporated herein in its entirety. 
     Drawing attention to  FIGS. 1 and 2 , the airway assembly  10  comprises an inner tube  12  having a central lumen, an inner surface  16  and an outer surface  18 , an outer tube  14  having a central lumen, having an inner surface  20  and an outer surface  22  and a diametrically expansive seal  30 . The inner tube  12  is disposed coaxially and reciprocally moveable within the outer tube  14 . There is sufficient clearance provided between the inner surface  20  of the outer tube  14  and the outer surface  18  of the inner tube  12  to permit movement of the inner tube  12  with respect to the outer tube  14 . A connector  24  is joined to the inner tube  12 , at a proximal end thereof, so that a fluid, such as a gas, a liquid and the like, can flow between the connector  24  and the inner tube  12 . Typically, a ventilator (not shown) is connected to connector  24  to provide an airflow to the patient. A distal end  28  of the inner tube  12  opposite to the proximal end thereof joined to the connector  24  is open to permit flow of fluid through the inner tube  12 . A port  26  is formed on the outer tube  14  so that fluid may flow between the port  26  and a space between the outer surface  18  of the inner tube  12  and the inner surface  20  of the outer tube  14 . In some embodiments, at least one perforation  72  is disposed on the outer tube  14 . The at least one perforation  72  passes between the inner surface  20  and the outer surface  22  of the outer tube  14 . The at least one perforation  72  allows for secretions collecting in the area above the diametrically expansive seal  30  to flow and be aspirated from an airway, it also allows for drug infusion or the like, between the outer tube  14  and the airway. The at least one perforation  72  may be positioned about 2 cm from the distal end  28  of the outer tube  14  and may be of any suitable shape, such as oblong, circular and the like, and any suitable size. Further, more than one perforation  72  may be included, and the more than one perforation  72  may be distributed along the length of the outer tube  14  in any desired manner. 
     Distal end  28  of the outer tube  14  is configured to facilitate introduction of the airway assembly  10  to a patient. The distal end  28  may have a bevel to facilitate passage through the vocal chords. Distal end  28  may also have a tapered diametric profile along its length, within the range of about 5 cm to about 7 cm in length, of a distal section of outer tube  14 . This distal taper may also be collapsible and allows for easier visualization during the intubation procedure. In some embodiments, the outer diameter of the outer tube  14  is substantially within the range of about 10 mm to about 12 mm at its proximal end and can be reduced to an outer diameter substantially within the range of about 6 mm to about 8 mm at the distal end  28   
     A diametrically expansive seal  30  is disposed at a distal end of the inner tube  12  opposite to the end thereof attached to the connector  24 . There is a substantially smooth transition between the inner tube  12  and the expansive seal  30 . The expansive seal  30  may comprise a generally tubular member having walls, a proximal end fixedly coupled to the inner tube  12 , and an uncoupled distal end which opens distally to the anatomical airway. The proximal end of the seal is coupled to a distal end of the inner tube  12  and is in fluid flow communication with the central lumen of the inner tube  12 . The walls and the distal end of the seal  30  may expand diametrically such that the distal end forms a diametrically enlarged distal opening sealingly seated against and in fluid flow communication with the airway. In some embodiments, the expansive seal  30  is movable between a diametrically collapsed position, shown in  FIGS. 1 and 2 , and a diametrically expanded position, shown in  FIGS. 3 through 7 . The expansive seal  30  has an inner surface  32  and an outer surface  34 . The diametrically expansive seal  30  serves to seal the airway while exerting minimal pressure in the mucosa sufficient to prevent aspiration of secretions from the upper airways and trachea into the lungs, while preventing back leakage of air given during respiratory ventilation or while ventilating anesthesia gas. 
     The expansive seal  30  may have many appropriate dimensions in length, diameter, or in its general shape, all of which depend upon the patient criteria or the anatomy of the target airway, e.g., trachea or bronchus. For purposes of example, only, one set of dimensions are appropriate for pediatric patients and another set of dimensions are appropriate for a patient with a very large airways. In one embodiment, the expansive seal  30  has an expanded outer diameter of about 25 mm while, in another embodiment, the expansive seal  30  has an expanded outer diameter of about 20 mm. The outer diameter of expansive seal  30  may be within the range of about 18 to 20 mm for adult males and within the range of about 16 to 18 mm for adult females. It is understood by those skilled in the art that as one places the expansive seal  30  further distally within the bronchial branches, the anatomical diameter decreases, necessitating smaller diameter expansive seals  30 . It is preferable, therefore, that the outer diameter of the expansive seal  30  be between about 10 to 25 mm in order to accommodate a wide variety of variances in anatomical structures of the trachea and bronchial branches. 
     An aperture  36  is on the expansive seal  30  adjacent the inner tube  12 . The aperture  36  permits fluid flow through the inner surface  32  of the expansive seal  30 . The aperture  36  is fluidly associated with the inner tube  12  to permit fluid flow between the inner tube  12  and the expansive seal  30 . 
     The expansive seal  30  is preferably fabricated of a biocompatible material, such as silicone, which is suitable for use in the pulmonary system, particularly the trachea and bronchi. The expansive seal  30  may be fabricated using a single material, wherein the seal is formed as a single monolithic or unitary element, or of plural joined elements formed of the same biocompatible material. Alternatively, the expansive seal  30  may be fabricated of plural biocompatible materials may be joined as a composite. In either construct of the expansive seal  30 , but more preferably, in the case of a composite construction of the expansive seal  30 , at least one reinforcing member  38  is operably associated with the expansive seal  30  to facilitate movement of the expansive seal  30  between its diametrically collapsed and diametrically expanded positions. In accordance with the illustrated embodiments, plural reinforcing members  38  are associated with the expansive seal  30  and extend longitudinally along the expansive seal  30  in a radially spaced apart relationship relative to each other. The at least one reinforcing member  38  may be coupled to the expansive seal  30  on either its luminal or abluminal surfaces, or may be embedded within expansive seal  30  such that it resides at least partially within a wall thickness of the expansive seal  30 . Alternatively, the at least one reinforcing member  38  may comprise a relatively thickened region, such as a rib or a pattern or ribs, of the same material employed in fabricating the expansive seal  30 . The at least one reinforcing member  38  is preferably an elastic, shape memory or superelastic material, such as stainless steel, silicone, nitinol, chromium-molybdenum alloys, or similar materials. In this manner the expansive seal  30  is self-expanding upon being released from a constraining sheath or covering, such as the outer tube  14 . For purposes of this application, when reference is made to expansive seal  30 , such reference is intended to be inclusive of the at least one reinforcing member  38 , where appropriate. Those of ordinary skill in the art will understand that the at least one reinforcing member  38  may or may not be necessary, depending upon the construction and materials employed in fabricating the expansive seal  30 , in order to provide for either expansion or collapse, or to facilitate or aid in apposition or sealing of the expansive seal  30  against the anatomical airway. 
     When in its diametrically expanded position, the expansive seal  30  is intended to achieve the size of the airway while exerting low pressure against the tracheal wall, thereby inhibiting passage of secretions beyond the expansive seal  30  to areas of the airway beyond the expansive seal  30 , and improving clearance from secretions deposited distal of the expansive seal  30 . The expansive seal  30  also reduces the likelihood of unintended fluid passage through the airway. In some embodiments, the expansive seal  30  may include at least one radiopaque or fluoroscopic marker to facilitate imaging the position of the expansive seal  30  after placement. The expansive seal  30  may take on any appropriate shape, for instance, the expansive seal  30  can be substantially elongated, substantially rounded or substantially horseshoe shape in transverse cross section. In longitudinal aspect, expansive seal  30  preferably has an elongate generally tubular shape with a rounded taper at a proximal end thereof that connects with the distal end of the inner tube  12 . The shape of the expansive seal  30  may be dictated by airway anatomy, by compatibility with the cough mechanism and by a need to reduce the likelihood of aspiration of secretions. In some embodiments, a distal portion of the expansive seal  30 , sometimes measuring about 2 to about 3 mm in axial length, may be everted to afford a smoother circumferential surface area for tissue engagement. Everting a distal portion of the expansive seal  30  may reduce potential tissue growth around the expansive seal  30 , and possibly facilitate advancement of the inner tube  12  with reduced risk of trauma to the patient. 
     Another embodiment of the airway assembly  10  is illustrated in  FIGS. 8 through 14 . As elements of this embodiment are substantially similar to elements of the embodiment shown in  FIG. 1 through 7 , like reference numerals are used for similar elements. The modifications in the airway assembly  10  are intended to provide independent ventilation to each one of the lungs as commonly required for surgical procedures such us lobectomies or in cases in which independent or single lung ventilation is desired. The following discussion highlights elements not previously emphasized. 
     The embodiments shown in  FIGS. 8 through 14  include modifications to provide both single and double lung ventilation. An inflatable member  40 , such as a balloon, is disposed proximate the distal end  28  of the outer tube  14 . The inflatable member  40  has an inner surface  42  and an outer surface  44  and is movable between a deflated position, shown in  FIGS. 8 and 9 , and an inflated position shown in  FIGS. 10 through 14 . In one embodiment, the inflatable member  40  is intended to fully inflate at a pressure substantially within the range of about 15 to about 30 cm H 2 O. At least one aperture  48  is disposed in the inner tube  12 . It is preferable according to this embodiment to provide at least two apertures  48 , as shown in  FIGS. 9 and 11  to permit the ventilation fluid to have sufficient flow to the second lung. The at least one aperture  48  is movable between an open position and a closed position by axially moving the inner tube  12  relative to outer tube  14 , the at least one aperture  48  is exposed to an open position or retracted within the outer tube  14  to a closed position. The at least one aperture  48  allows fluid movement through the aperture  48  and passing between the interior and exterior of the inner tube  12 . However, it is to be noted that, because the inner tube  12  is moveable with respect to the outer tube  14 , the tubes  12  and  14  may be positioned such that fluid flow through the at least one aperture  48  is restricted, i.e. the at least one aperture  48  is in a closed position.  FIGS. 8 and 9  illustrate the relative position between inner tube  12  and outer tube  14  wherein the at least one aperture  48  is in the closed position within the outer tube  14 . Hence, it is to be appreciated that fluid flow through the at least one aperture  48  is dependent upon relative position of the inner tube  12  and the outer tube  14 . It is to be noted that while the Figures show that the inflatable member  40  is in its inflated position when the expansive seal  30  is in its expanded position, and the inflatable member  40  is in its deflated position when the expansive seal  30  is in its collapsed position, this does not always have to be the case. For example, the inflatable member  40  may be in its deflated position when the expansive seal  30  is in its expanded position or the inflatable member  40  may be in its inflated position while expansive seal  30  is in its collapsed position. 
     An inflation port  46  is disposed in communication with the outer tube  14  and communicates with the inner surface  42  of the inflatable member  40  so that fluid can flow between the port  46  and the inflatable member  40 . A suitable conduit, not shown for clarity, is disposed on or in the outer tube  14  for conveying an inflation fluid between the inflation port  46  and the inflatable member  40 . In this manner, this fluid flow controls inflation or deflation of the inflatable member  40  between its inflated and deflated positions. Once the endotracheal tube is placed such that the distal end of the inner tube  12  is positioned at a desired location in the right or left bronchus, the outer tube  14  is retracted to release the expansive seal  30  permitting expansive seal  30  to diametrically expand and sealingly conform against the bronchus. The outer tube  14  is retracted sufficiently to position the inflation member  40  at a desired location within the trachea and inflated into sealing conformity against the trachea. If the apertures  48  are exposed, ventilation will occur to both lungs, with one lung being ventilated through the expansive seal  30  and the other lung being ventilated through the apertures  48 . If the apertures  48  are in their closed position, ventilation will only occur within the lung communicating with the bronchus in which the expansive seal  30  is positioned. 
     Another embodiment of the airway assembly  10  is shown in  FIGS. 15 through 21 . This embodiment is substantially similar to the embodiment shown in  FIGS. 8 through 14 , hence the like reference numerals for similar structures. However, the embodiment illustrated in  FIGS. 15 through 21  includes at least one aperture  48  and two seals, including a first expansive seal  30 A and a second expansive seal  30 B. Each of the seals  30 ,  30 A and  30 B are preferably similar construction and include at least one reinforcing member  38  as previously described. Both seals  30 A and  30 B are carried on the inner tube  12  and diametrically expand independently between expanded and collapsed positions, depending on relative position of the inner tube  12  and the outer tube  14 . While  FIGS. 15 and 21  show both seals  30 A and  30 B being simultaneously in the same position, either expanded or collapsed, it is to be noted that the expansive seal  30 A may be in its expanded position while the expansive seal  30 B is in its collapsed position, depending upon the relative position of the inner tube  12  relative to the outer tube  14 . Significantly, as can be appreciated by considering  FIGS. 15 ,  16  and  18 , when expansive seal  30 B is in its collapsed position, expansive seal  30 B covers aperture  48  thereby restricting fluid flow through the aperture  48 . 
     A further embodiment of the airway assembly  10  is shown in  FIGS. 22 through 28 . This embodiment is substantially similar to the embodiments shown in  FIGS. 8 through 14 . However, in this embodiment, both the expansive seal  30  and the inflatable member  40  are disposed on the inner tube  12  and in an order reversed from the order of those items as depicted in  FIGS. 8 through 14 . This embodiment demonstrates that elements of the airway assembly  10  may be arranged in any appropriately desired way to arrive at an airway assembly  10  that meets particular needs. 
     Drawing attention to  FIG. 22 , the inflation port  46  is associated with and positioned at a proximal end of the inner tube  12 . A suitable conduit, not shown for clarity, is provided in association with the inner tube  12  for conveying fluid between the port  46  and the inflatable member  40  that is disposed on the inner tube  12  as described above. The expansive seal  30  is connected with the inner tube  12  at a position between the inflatable member  40  and the connector  24  relative to the longitudinal axis of the inner tube  12 . The at least one aperture  48  passes through the inner tube  12  and is positioned such that the expansive seal  30 , when in its collapsed position, covers and closes the at least one aperture  48 . As discussed previously, the positions of the inflatable member  40  and the expansive seal  30  can be changed from what is shown in  FIGS. 22 through 28 . For example, the inflatable member  40  may be in its collapsed position while the expansive seal  30  is in its expanded position or the longitudinal spacing of the inflatable member  40  and expansive seal  30  along the longitudinal axis of the inner tube  12  may be altered. 
     An additional embodiment of the airway assembly  10  is shown in  FIGS. 29 through 35 . This embodiment is similar to the embodiment illustrated in  FIGS. 8 through 14  in that both include an expansive seal  30 , an inflatable member  40  and at least one aperture  48 . However, in this embodiment, the expansive seal  30 , the inflatable member  40  and the at least one aperture  48  are all disposed on the inner tube  12 . 
     The inflation port  46  is disposed at a proximal end of the inner tube  12  proximate the connector  24 . As described above with reference to other embodiments, a suitable inflation conduit, not shown for clarity, is associated with the inner tube  12  for conveying an inflation fluid between the inflation port  46  and the inflatable member  40  that is disposed on the inner tube  12  as well. The expansive seal  30  is disposed on the inner tube  12  such that the inflatable member  40  is located between the expansive seal  30  and the connector  24 . The at least one aperture  48  passes through the inner tube  12  and is positioned between the expansive seal  30  and the inflatable member  40 . In this configuration, fluid flow through the at least one aperture  48  is not dependent upon whether the expansive seal  30  is in its expanded or collapsed position. Fluid flow through the at least one aperture  48  is limited by appropriate relative positioning of the inner tube  12  and the outer tube  14 , as shown in  FIGS. 31 through 34 . 
     With structure of the airway assembly  10  having been discussed with reference to the foregoing embodiments now an exemplary method of use of an airway assembly will be explained. To ease understanding, the embodiment of the airway assembly  10  similar to that shown in  FIGS. 8 through 14  will be used. It is to be understood that any of the embodiments described herein can be used with this method with suitable modifications to either the method or to the assembly  10 . Furthermore, additional features of the airway assembly  10  may become apparent to those skilled in the art upon review of the following description. 
     Beginning with  FIG. 36 , the airway assembly  10 , including inner tube  12  and outer tube  14 , is prepared for insertion into a patient to provide single or double lung ventilation. Positioning marks may be placed on the inner tube  12  to indicate to the physician the relative positions of the inner tube  12  and the outer tube  14  and whether the airway assembly  10  is in a single lung ventilation mode or in a dual lung ventilation mode. A first positioning mark  50  and a second positioning mark  52  indicate the status of the expansive seal  30  and the condition of the at least one aperture  48 . Specifically, the first positioning mark  50  is provided distally to indicate that an expansive seal  30  is collapsed and within the outer tube  14 , a first intermediate mark (not shown), proximal to the distal positioning mark  50 , may indicate that the expansive seal  30  is expanded and that the at least one aperture  48  is closed and covered within the outer tube  14 , a second intermediate mark (not shown), proximal to the first intermediate mark, may indicate that the expansive seal  30  is expanded and that the at least one aperture  48  is exposed and uncovered by the outer tube  14 , and the second positioning mark  52  is provided proximally to indicate that the expansive seal  30  is expanded, the at least one aperture  48  is open and, where present, a proximal expansive seal is expanded. It will be understood that depending upon the specific configuration and number of expansive seals  30  and apertures  48 , variations in the number and positioning of the positioning marks  50 ,  52  are contemplated in order to provide the physician with an indicator of the status of the respective expansive seals  30  or apertures  48 . 
     When a proximal end  53  of the outer tube  14  is located distally of the first mark  50  (a first status of the airway assembly  10 ), the expansive seal  30  is in a collapsed position and the at least one aperture  48  is in its closed position. When a proximal end  53  of the outer tube  14  is adjacent the first mark  50  (a second status of the airway assembly  10 ), the expansive seal  30  is in its expanded position and the at lest one aperture  48  is in its close position. When in the second status of the airway assembly  10 , ventilation of a single lung, through the inner tube  12  and the aperture  36  in the expansive seal  30 , is possible. Ventilation of both lungs is accomplished by positioning the proximal end  53  of the outer tube  14  adjacent the second mark  52  (a third status of the airway assembly  10 ), the expansive seal  30  is in its expanded position and the at least one aperture  48  positioned in the inner tube  12  is in its open position, and the inflatable member  40  is inflated to seal the airway, thereby allowing an operator, such as a doctor and the like, of the airway assembly  10  to provide ventilation to both lungs. Thus, it can be appreciated that the first status of the airway assembly  10  corresponds to an initial status of the airway assembly  10 , the second status of the airway assembly  10  corresponds to a single lung ventilation status of the airway assembly  10 , and the third status of the airway assembly  10  corresponds to a dual lung ventilation status of the airway assembly  10 . In some embodiments, there may be more or less marks provided on the inner tube  12  or the outer tube  14  or both, thereby providing more airway assembly  10  status indicators. In operation, the first mark  50  is a distal mark that indicates that the outer tube  14  is pulled back to expose the aperture  48 , the inflation member  40  is expanded, and double lung ventilation is being performed. The second mark  53  is a proximal mark that indicates that the outer tube  14  is positioned to cover and close the aperture  48 , the inflation member  40  is deflated, and the expansive seal  30  is deployed in a bronchi and single lung ventilation is being performed. 
     As shown in  FIGS. 36 through 38 , after the airway assembly  10  is passed through the vocal chords using a laryngoscope, an endoscope  54 , such as a bronchoscope and the like, is placed coaxially through the central lumen of the inner tube  12  to visualize distally the airway assembly  10  and provide placement guidance for the airway assembly  10 . Once the intended position for placement of the expansive seal  30  is identified, the endoscope  54  acts like a guidewire for the airway assembly  10  to permit placement of the expansive seal  30  in the patient&#39;s right or left bronchial tree to permit single lung ventilation to the right or left lung respectively. 
       FIG. 37  illustrates portions of the airway assembly  10  and the endoscope  54  inserted into a patient. For ease of understanding, elements of the airway assembly  10  are represented transparently. A distal end  56  of the endoscope  54  is positioned within a first bronchus  58  of the patient. The first bronchus  58  is associated with a first lung  60 . Of course, there is a second bronchus  62  associated with a second lung  64 . The operator positions the distal end  56  of the endoscope  54  at a desired position in the first bronchus  58 . The airway assembly  10  is advanced along the endoscope  54  to the desired position. As shown in  FIG. 37A , some embodiments of the airway assembly  10  include a narrowed distal region  66 , located adjacent distal ends, where the diameter of the inner tube  12  and the diameter of the outer tube  14  are reduced from other more proximal portions of those elements. In this embodiment, the expansive seal  30  may have an outer diameter within the range of about 10 to 15 mm. In some embodiments, the reduced dimensions are outer diameters which, adjacent distal ends, are smaller than outer diameters adjacent proximal ends of the same element, such as the inner tube  12 , the outer tube  14  and the expansive seal  30 . These reduced dimensions facilitate introduction of the airway assembly  10  into the patient by, for example, increasing ease of moving the distal end  28  of the outer tube  14  beyond vocal cords or glottic space of the patient. In some embodiments, the narrowed distal region  66  is substantially within the range of about 5 to about 8 cm in axial length, and has a maximum outer diameter substantially within the range of about 6 to about 10 mm. In some embodiments, when the expansive seal  30  is in its collapsed position, the expansive seal  30  has an outer diameter substantially equal to the outer diameter of the inner tube  12  adjacent the expansive seal  30 . 
     To further facilitate introduction and maneuvering of the airway assembly  10 , portions of the inner tube  12  and the outer tube  14  may be comprised of different materials having different physical and/or material properties. For example, proximal portions of the tubes  12  and  14  may be stiffer and more rigid than distal portions of the tubes  12  and  14 . This construction may ease the advancement of the airway assembly  10  in the patient with reduced deformation or curving of the tubes  12  and  14 . Further, the relatively softer and more malleable material comprising the distal portions of the tubes  12  and  14  may allow for deformation or compression of distal ends of the tubes  12  and  14 , and also may be more accommodating to the operator. 
     In some embodiments, instead of having a tapered distal region  66 , the inner tube  12  can have a substantially constant outer diameter similar to the outer diameter of the tapered distal region  66 . This construction can reduce an outer diameter or profile of the airway assembly  10 , and can facilitate aspiration through the space between the outer surface  18  of the inner tube  12  and the inner surface  20  of the outer tube  14 . In other embodiments, both the inner tube  12  and the outer tube  14  can have substantially constant outer diameters, thereby making the region  66  unnecessary. 
     As shown in  FIG. 38 , the airway assembly  10  is moved with respect to the patient to position the distal end  28  within the first bronchus  58 . At this location, it is desired to move the expansive seal  30  from its collapsed position to its expanded position. Related conditions of a proximal end of the airway assembly  10  are shown in  FIG. 39  (first location with expansive seal  30  collapsed) and  FIG. 41  (second location with seal expanded). Note the relative locations of the marks  50  and  52  and the end  53 . The outer tube  14  is moved to allow the expansive seal  30  to diametrically expand from its collapsed position to its expanded position. The endoscope  54  is then removed from the airway assembly  10  as shown in  FIG. 40 . 
     In its expanded position, the outer surface  34  of the expansive seal  30  contacts an inner surface of the first bronchus  58 . The contact pressure between the outer surface  34  and the first bronchus  58  is sufficient to exclude secretions from passing across expansive seal  30  and into the first lung  60 . However, that contact is insufficient to harm the first bronchus  58 . With the expansive seal  30  in its expanded position, fluid can flow among the connector  24 , the inner tube  12 , the aperture  36 , the first bronchus  58  and the first lung  60 . This fluid flow is indicated generally by arrow  68  of  FIGS. 40 and 41 ; under this condition the airway assembly is providing single lung ventilation to the first lung  60 . This arrangement allows fluid to flow among the connector  24 , the inner tube  12 , the aperture  36 , the first bronchus  58  and the first lung  60  while limiting fluid flow to or from the second bronchus  62  and the second lung  64 . This configuration permits single lung ventilation while excluding ventilation to the other lung. 
     It is not necessary to have the inflatable member  40  in its expanded position to ventilate a single lung. During single lung ventilation, the inflatable member  40  may be either in its deflated or inflated positions. When the patient&#39;s condition requires ventilation of both lungs, the outer tube  14  is moved with respect to the inner tube  12  so that the aperture  48  is moved to its open position. The proximal end  53  is adjacent the second mark  52 . This is the third location (the at least one aperture  48  in its open position) and is shown in  FIGS. 42 and 43 . The inflatable member  40  is moved to its inflated position. By doing this, unintended back fluid flow is limited. 
     This status of the airway assembly  10  permits fluid flow among the connector  24 , the inner tube  12 , the aperture  48 , the second bronchus  62  and the second lung  64 . This fluid flow is represented by arrow  70  of  FIG. 42 . Fluid flow  68  occurs as well. The inflatable member  40  is changed to its inflated position. The proximal end of the airway assembly  10  is shown in  FIG. 43 . This configuration permits both lungs to be ventilated. 
     When the clinical condition does not require single lung ventilation, such as at the end of a surgical procedure, as shown in  FIG. 44 , the inner tube  12  is moved pulled back proximally with respect to the outer tube  14  thereby capturing the expansive seal  30  within the outer tube  14  and collapsing the expansive seal  30 . Fluid then flows to both the first lung  60  and the second lung  64 . In this position, the airway assembly  10  is its delivery configuration, as shown in FIG.  45 , and the airway assembly  10  may remain within the patient to provide continued intubation or the airway assembly  10  may be removed. 
     Those of ordinary skill in the art will understand and appreciate that the foregoing description of the invention has been made with reference to certain exemplary embodiments of the invention, which describe airway assemblies suitable for single and/or dual lung ventilation, while excluding passage of secretions across the expansive seal  30 . Those of skill in the art will understand that obvious variations in construction, materials, dimensions or properties may be made without departing from the scope of the invention which is intended to be limited only by the claims appended hereto.