Abstract:
A medical ventilation device comprising a cannula having proximal and distal ends; an inflatable cuff adapted to be inflated to an inspiratory pressure, the cuff attached to and surrounding a portion of the cannula toward the distal end thereof; an inspiratory pressure inflation tube having first and second ends, the first end in communication with an interior of the inflatable cuff, the second end adapted to communicate with an inspiratory pressure source; and a pressure valve in communication with the inspiratory pressure inflation tube.

Description:
TECHNICAL FIELD  
       [0001]     The present disclosure, according to one embodiment, relates to inflatable cuffs for medical applications, and more particularly, to the controlled inflation of cuffs, such as, for example, cuffs surrounding a portion of tubes used in respiratory care such as tracheostomy or endotracheal tubes. For the purposes of the present disclosure, tracheostomy and endotracheal tubes will be referred to collectively as “tracheal tubes,” unless otherwise stated.  
       BACKGROUND  
       [0002]     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.  
         [0003]     Tracheal tubes may be inserted for a variety of reasons, including mechanical ventilation, bypass of an obstruction, removal of secretions, and easier ventilation due to less dead space. In some circumstances, it may be desirable to seal the outside of the tracheal tube to the inner tracheal lining, i.e., the tracheal mucosa. During mechanical ventilation, this may be particularly true, since a closed circuit may be desirable for a ventilator to force a given volume of air or oxygen under pressure into a subject&#39;s lungs. When a subject is not being mechanically ventilated, a seal may or may not be used. Whether a seal is used generally depends on whether there is a risk of aspiration. Therefore, sometimes a seal is used either to prevent aspiration or to create a closed circuit for mechanical ventilation.  
         [0004]     Tracheal tubes typically follow a basic concept that utilizes a curved, “L” shaped tube which serves as an artificial passage for exchange of air between a subject and an air source, typically either atmospheric air or a mechanical respirator. The tube is often enveloped at its distal end by a small, inflatable cuff, also called a balloon, which is inflated with a gas, such as air, or in some cases a liquid. The cuff engages the internal lining of the trachea in its cross-section to prevent air insufflated by a respirator into a subject from escaping to the environment through the tracheostomy or the larynx and pharynx, thus enabling the air or gas mixture to reach the lower airways by bulk flow and the pulmonary alveoli by diffusion (also referred to as positive pressure ventilation). The cuff also may aid in supporting the tube inside the trachea and in substantially the same axis as the trachea (e.g., to prevent the tube&#39;s tip from contacting the tracheal wall), as well as protecting the airway from aspiration.  
         [0005]     The cuffs are usually manually inflated with pressurized air from a syringe or a manometer through a small bore “pilot tube.” The air is injected into the proximal end of the pilot tube, which usually is a thin piece of tubing for its proximal half and a small diameter channel molded into the wall or on the surface of the tracheal tube for its distal half. The pilot tube terminates at its distal end within the inflatable cuff of the tracheal tube. The pilot tube may have a one-way valve at its proximal end to maintain pressure within the system.  
         [0006]     Experience has shown that the intracuff pressure is usually maintained at less than the arterial end-capillary pressure, which is typically about 25 cm H 2 O. This is consistent with experimental data suggesting that the capillary perfusion pressure in the tracheal mucosa is in the range of 30-40 cm H 2 O. Thus, a cuff pressure of 25 cm H 2 O normally allows some blood flow. However, the numbers noted above are not absolute. Cuff pressures of 25 cm H 2 O may be occasionally too high because perfusion pressures may be lower than expected due, for example, to low blood pressure. Therefore, the best approach is typically to use the lowest cuff pressure consistent with achieving a tracheal-cuff and mucosal seal that allows positive-pressure ventilation and prevents aspiration into the trachea.  
         [0007]     Intracuff pressure may increase when an anesthetic is administered, for example, during surgery. The anesthetic gas nitrous oxide may diffuse through the cuff material and into the cuff. The volume of gas within the cuff can increase because of nitrous oxide diffusion. The pressure within the cuff then increases and, therefore, the pressure against the tissue of the tracheal wall is also increased. This slowly increasing cuff pressure may not be detected by the clinician.  
       SUMMARY  
       [0008]     Therefore, there is a need for cuffed tubes that are more stable within a subject than currently available tubes, while minimizing pressures within the cuffs.  
         [0009]     In general, the tracheal tubes of the present disclosure may comprise an auto-inflating cuff to sealingly engage the trachea of a subject. “Auto-inflation,” as used herein, refers to inflation of a cuff through inspiratory pressure. The pressure within the auto-inflating cuff may be regulated, controlled, or adjusted through the use of an integrated or attached pressure valve, as well as by restricting the flow of air into and/or out of the cuff.  
         [0010]     When placed in the trachea, the devices and systems according to specific example embodiments of the present disclosure may perform a variety of functions. For example, they may be useful in preserving or maintaining the airway of a subject while, among other things, preventing ischemia of the tracheal mucosa and/or preventing aspiration. Such devices and systems may be particularly useful, among other things, in pediatric subjects, where damage to the tracheal mucosa occurs more readily. Such devices and systems also may be particularly useful in applications, for example, that require long term intubation.  
         [0011]     The devices and systems according to specific example embodiments of the present disclosure also may, among other things, reduce the occurrence of undesirable displacement during ventilation or movement of a subject, allow for stabilization of the cuff using lower intracuff pressures, and allow for smaller sized cuffs.  
         [0012]     The present disclosure, according to a specific example embodiment, provides a medical ventilation device comprising a cannula having proximal and distal ends; an inflatable cuff adapted to be inflated to an inspiratory pressure, the cuff attached to and surrounding a portion of the cannula toward the distal end thereof; an inspiratory pressure inflation tube having first and second ends, the first end in communication with an interior of the inflatable cuff, the second end adapted to communicate with an inspiratory pressure source; and a pressure valve in communication with the inspiratory pressure inflation tube.  
     
    
     DRAWINGS  
       [0013]     Some embodiments of the disclosure may be understood by referring, at least in part, to the following description and the accompanying drawings in which:  
         [0014]      FIG. 1A  is a schematic diagram of a ventilation system, according to a specific example embodiment of the present disclosure;  
         [0015]      FIG. 1B  is a schematic diagram of a ventilation system, according to another specific example embodiment of the present disclosure;  
         [0016]      FIG. 2A  is a schematic of a tracheal tube, according to a specific example embodiment of the present disclosure;  
         [0017]      FIG. 2B  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0018]      FIG. 3A  is a cross-sectional schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0019]      FIG. 3B  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0020]      FIG. 3C  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0021]      FIG. 3D  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0022]      FIG. 3E  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0023]      FIG. 4A  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0024]      FIG. 4B  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0025]      FIG. 4C  is a cross-sectional schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0026]      FIG. 4D  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure;  
         [0027]      FIG. 5  is a schematic of a tracheal tube, according to another specific example embodiment of the present disclosure. 
     
    
     DESCRIPTION  
       [0028]     One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.  
         [0029]     Referring now to the drawings, the details of specific example embodiments are schematically illustrated. Like elements in the drawings will be represented by like numbers, and similar elements will be represented by like numbers with a different lower case letter suffix.  
         [0030]     Referring to  FIG. 1A , depicted is a schematic diagram of a ventilation system, according to a specific example embodiment of the present disclosure. A subject  101  has a stoma  103  (opening) leading to trachea  105  in which tracheal tube  100  is inserted. A flange  109  may be attached to subject&#39;s  101  neck, for example, by tape, straps, and the like (not shown). Integrally formed with flange  109 , or proximate thereto, may be one or more of a pressure valve (not shown), a cuff connector site (not shown), a pilot balloon (not shown), and a tube (not shown). A ventilator hose  111  may couple a ventilator  113  to connector  108 . A heat and moisture exchange (“HME”) filter (not shown), which may include one or more ports and/or cuff connector sites, may be included between ventilator  113  and cannula  102 , for example, integral with connector  108 . An inflation cuff  110  may be proximate to the outer wall of cannula  102 , and an inflation tube  118  may be within the outer wall of cannula  102  or proximate thereto.  
         [0031]     Referring to  FIG. 1B , depicted is a schematic diagram of a ventilation system, according to a specific example embodiment of the present disclosure. Tracheal tube  100  is inserted through subject&#39;s  101  mouth  107  and into trachea  105 . A ventilator hose  111  may couple a ventilator  113  to connector  108 . Integrally formed with flange  109 , or proximate thereto, may be one or more of a pressure valve (not shown), a cuff connector site (not shown), a pilot balloon (not shown), and a tube (not shown). A heat and moisture exchange (“HME”) filter (not shown), which optionally may include one or more ports and/or cuff connector sites, may be included between ventilator  113  and cannula  102 . An inflation cuff  110  may be proximate to the outer wall of cannula  102 , and an inflation tube  118  may be within the outer wall of cannula  102  or proximate thereto.  
         [0032]     Referring to  FIG. 2A and 2B  depicted are schematic diagrams of tracheal tubes, according to specific example embodiments of the present disclosure. Tracheal tube  100  may comprise cannula  102  having a proximal end  104  and a distal end  106 . Cannula  102  may be sized to fit within the trachea of a subject, and may be formed, for example, from a length of flexible, tissue-compatible plastics, such as polyvinyl chloride or another plastic, silicon rubber, or another sufficiently flexible material. The proximal end  104  of cannula  102  may include connector  108  having flange  109 . If desired, connector  108  may be used to connect tracheal tube  100  to a breathing apparatus or appropriate ventilator. Connector  108  may have standard sizes, among other things, to conveniently mate with commercially available breathing equipment. Tracheal tube  100  also may include an HME filter. Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0033]     An inflatable cuff  110  sheathes cannula  102  at the distal end  106 . Cuff  110  may be adapted to provide, when placed in a subject, an airway seal during positive-pressure ventilation, protection from aspiration, or both, without causing significant trauma to the trachea. Accordingly, cuff  110  may be formed so as to have a sufficiently large cuff volume to fill a gap between the outer wall of cannula  102  and the inner wall of a subject&#39;s trachea (not shown). Cuff  110  may comprise a flexible, inflatable, circumferential cuff or balloon. Cuff  110  may be formed from any biocompatible material. For example, cuff  110  may be formed from a thin film of plastic (e.g., polyurethane), rubber, or another flexible material. Cuff  110  may be formed from a material resistant to gas (e.g., nitrous oxide, oxygen) permeation, such as a crosslinked, polyester polyurethane resin, or cuff  110  may be formed from a material having a thickness which resists gas permeation; however, resistance to gas permeation may not be necessary, as cyclic inflation evacuates additional amounts of gases.  
         [0034]     The cuff  110  may be inflated by means of inflation tube  118  extending along cannula  102 . Tube  118  may be separate from cannula  102 , or tube  118  may be integrally formed with the wall of cannula  102  (not shown). Tube  118  is in communication with the interior of cuff  110  for inflation and deflation thereof, and the other end of tube  118  may be in communication with both an inspiratory pressure source (e.g., a ventilator), as well as in communication with one or more of the internal lumen of cannula  102 , cuff connector site  114 , HME filter (not shown), T-Piece-adapter (not shown), and a pressure valve (not shown). The term pressure valve, as used herein, refers a device for one or more of controlling, regulating, adjusting, maintaining, and releasing intracuff pressure. Examples of pressure valves include, but are not limited to, pressure regulators, pressure release valves, adjustable valves, and air passageways configured to trap or restrict air flow to or from a cuff. Tube  118  may be adapted to receive pilot balloon  116 . Alternatively, tube  118  may be integrally formed with pilot balloon  116 , for example, by expanding tube  118  into a balloon shape having sufficient compliance. Pilot balloon  116  is in communication with cuff connector site  114 , which may be located on flange  109  at the proximal end  104  of the tracheal tube  100 . Cuff connector site  114  may be adapted to receive pilot balloon  116  and communicates with the lumen of connector  108 , thereby providing a passageway to inflate cuff  110 . Pilot balloon  116  and cuff connector site  114  may be disposed distally to flange  109  (e.g., axially to cannula  102 ) (shown in  FIG. 2B ). Such a configuration may place pilot balloon  116  and cuff connector site  114  within a subject. Alternatively, pilot balloon  116  and cuff connector site  114  may be disposed proximally to flange  109  (shown in  FIG. 2A ).  
         [0035]     Tube  118  may be configured to decrease deflation of the cuff  110  during expiration, or to partially trap air in cuff  110 . In this way, expansion of cuff  110  may be maintained during expiration while ensuring that the pressure within cuff  110  does not exceed the peak airway inflation pressure during inspiration. Suitable configurations include, but are not limited to, forming tube  118  to progressively expand distally, narrowing the inner diameter of tube  118 , and providing an adjustable regulator or valve capable of restricting airflow through tube  118 . Optionally, the upper inflation pressure may be regulated with a pressure release valve (not shown).  
         [0036]     For fully deflating the cuff  110  (e.g., for extubation and/or air leak testing), the pilot balloon  116  may be disconnected from connector site  114  and manually deflated using, for example, a syringe connected to the pilot balloon  116 . Alternatively, an additional port (not shown) for evacuating air from cuff  110  may be integral with connector  108 , for example, at flange  109 . When included, the port may be in communication with tube  118 . The port also may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  and/or to equalize the pressure in cuff  110  to ambient pressure. The port may be adapted to receive a cap (not shown). The port also may be used for attachment of a monitoring device or regulator, for example, an electronic cuff pressure regulator (not shown) to, among other things, measure intracuff pressure. A separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at the port or integral with the port.  
         [0037]     In use, tracheal tube  100  may be placed into the windpipe through the mouth, through the nose, or through a tracheotomy, for example, to facilitate narcosis respiration or therapeutic respiration. Inspiratory pressure from a ventilator (not shown) provides air through tube  118  and into cuff  110 . In this way, the inspiratory pressure may provide the means to inflate cuff  110  to sealingly engage tracheal tube  100  in the trachea of a subject. Such auto-inflation may allow, among other things, sealing of the trachea without the acute and sustained hyperinflation arising from syringe or manometer inflation. Auto-inflation of cuff  110  may allow the intracuff pressure to be equal to, or less than, the airway pressure in the trachea. In this regard, use of the tracheal tubes according to present disclosure may prevent damage to a subject&#39;s trachea, among other things, because cuff  110  may engage the trachea in proportion to the inspiratory pressure. In addition, insufflated gases that may diffuse into cuff  110  should not increase intracuff pressure, among other things, because with expiration, diffused gases are allowed to escape from cuff  110 . Use of tracheal tube  100 , as well as other tracheal tubes of the present disclosure, may free a clinician from monitoring cuff pressure, among other things, because upper inspiratory pressure may be noted from, for example, a ventilator.  
         [0038]     Referring to  FIG. 3A , depicted is a cross-sectional schematic diagram of a portion of a tracheal tube  100 , according to another specific example embodiment of the present invention. In this embodiment, cuff  110  (not shown) may be inflated by means of inflation tube  318  extending along and integrally formed with cannula  102 . Tube  318  is in communication with the interior of cuff  110  (not shown) for inflation and deflation thereof, and the other end of tube  318  is in communication with the lumen of cannula  102  via opening  322 , thereby providing a passageway to inflate cuff  110 . Port  320  may be attached to the wall of cannula  102  and is in communication with tube  318 . Port  320  may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  or to equalize the pressure in cuff  110  to ambient pressure. Port  320  may be adapted to receive a cap (not shown) and a pressure valve  330  (e.g., a pressure release valve). Pressure valve  330  may be adjustable or fixed. Such a pressure valve, among other things, may help prevent excessive intracuff pressure during intermittent positive pressure ventilation (“IPPV”). Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0039]     Referring to  FIG. 3B  and  FIG. 3C , depicted are schematic diagrams of tracheal tubes  100 , according to other specific example embodiments of the present disclosure. In these embodiments, an adjustable pressure valve  220  may be positioned distally to connector  108  or integral to connector  108  (not shown), and be in communication with the lumen of cannula  102  and cuff connector site  114 . In this way, adjustable pressure valve  220  may be placed so as to affect the pathway of air to cuff  110 . Examples of adjustable pressure valves include, but are not limited to, pressure regulators, pressure release valves, adjustable valves, and air passageways configured to trap or restrict air flow to or from a cuff. Such a pressure valve may help ensure that sufficient intracuff pressure is provided to cuff  110  and/or maintained in cuff  110  during IPPV, as well as during spontaneous ventilation, such that cuff  110  remains substantially sealingly engaged to the trachea. The use of a pressure valve may substantially minimize any air leakage from the higher tracheal airway pressure as compared to ambient pressure at the positive-end expiratory pressure (“PEEP”) values that occur during expiration. In one aspect, adjustable pressure valve  220  may also act as a positive pressure inflation valve, among other things, to limit the upper intracuff pressure during inspiration (peak inspiratory pressure, “PIP”). In another aspect, a separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at connector site  114  or integral with connector site  114 . Adjustable pressure valve  220  may be adjusted in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. Adjustment of pressure valve  220  may be achieved, for example, by turning adjustment ring  222  having, for example, an adjustable orifice (not shown). Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0040]     For fully deflating cuff  110  (e.g., for extubation), the pilot balloon  116  may be disconnected from connector site  114  and manually deflated using, for example, a syringe connected to the pilot balloon  116 . Alternatively, an additional port (not shown) for evacuating air from cuff  110  may be integral with pressure valve  220  or flange  109 . In this regard, air may be evacuated positioning adjustment ring  222  to allow evacuation through the port using, for example, a syringe or ambient pressure. When included, the port may be in communication with tube  118 . The port also may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  or to equalize the pressure in cuff  110  to ambient pressure. The port may be adapted to receive a cap (not shown). The port also may be used for attachment of a monitoring device or regulator, for example, an electronic cuff pressure regulator (not shown) to, among other things, measure intracuff pressure. A separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at the port or integral with the port.  
         [0041]     Referring to  FIG. 3D , depicted is a schematic diagram of a portion of a tracheal tube  100 , according to another specific example embodiment of the present invention. In this embodiment, cuff  110  (not shown) may be inflated by means of inflation tube  118  extending along cannula  102 . Tube  118  is in communication with the interior of cuff  110  (not shown) for inflation and deflation thereof, and the other end of tube  118  is in communication with the internal lumen of an interposed T-piece  221  via pilot balloon  116  and connector site  114 , thereby providing a passageway to inflate cuff  110 . The T-piece  221  is interposed between connector  108  and respirator circuit tube (not shown). Adjustable pressure valve  220  may be integral to T-piece  221  and be in communication with the lumen of the T-piece and cuff connector site  114 . In this way, adjustable pressure valve  220  may be placed so as to affect the pathway of air to cuff  110 . Adjustable pressure valve  220  includes connector site  114  and adjustment ring  222 . The cuff connector site  114  on pressure valve  220  may be adapted to receive a pilot balloon  116  and a cap (not shown). Pilot balloon  116  may be adapted to receive tube  118 . Alternatively, tube  118  may be integrally formed with pilot balloon  116 , for example, by expanding tube  118  into a balloon shape having sufficient compliance. T-piece  221  also may include an HME filter (not shown).  
         [0042]     Adjustable pressure valve  220  may help ensure that sufficient intracuff pressure is provided to cuff  110  and/or maintained in cuff  110  during IPPV, as well as during spontaneous ventilation, such that cuff  110  remains substantially sealingly engaged to the trachea. The use of a pressure valve may substantially minimize any air leakage from the higher tracheal airway pressure as compared to ambient pressure at the PEEP values that occur during expiration. In one aspect, adjustable pressure valve  220  may also act as a positive-pressure inflation valve, among other things, to limit the upper intracuff pressure during inspiration. Adjustment of adjustable pressure valve  220  may be achieved by positioning adjustment ring  222  having, for example, an adjustable orifice (not shown).  
         [0043]     Referring to  FIG. 3E , depicted is a schematic diagram of a portion of a tracheal tube  100 , according to another specific example embodiment of the present invention. In this embodiment, cuff  110  (not shown) may be inflated by means of inflation tube  118  extending along cannula  102 . Tube  118  is in communication with the interior of cuff  110  (not shown) for inflation and deflation thereof, and the other end of tube  118  is in communication with the lumen of HME filter  325 , thereby providing a passageway to inflate cuff  110 . Adjustable pressure valve  324  may be integral of the HME filter  325 , and be in communication with it&#39;s lumen and cuff connector site  114 . In this way, adjustable pressure valve  324  may be placed so as to affect the pathway of air to cuff  110 . Adjustable pressure valve  324  includes connector site  114 , port  320   a  and  320   b,  and adjustment ring  222   a  and  222   b.  Cuff connector site  114  may be adapted to receive tube  118 , a pilot balloon (not shown), and a cap (not shown). Port  320   a  and  320   b  may be adapted to receive a cap (not shown) and a pressure valve (not shown), for example, a pressure release valve. Port  320   a  may be selectively openable, for example, by positioning adjustment ring  222   a  and/or  222   b  to allow access to cuff  110  for, among other things, evacuation of the cuff through the port using, for example, a syringe or ambient pressure. Port  320   b  may be used for attachment of a monitoring device, for example, an anesthesia gas monitoring unit (not shown).  
         [0044]     Adjustable pressure valve  324  may help ensure that sufficient intracuff pressure is provided to cuff  110  during IPPV, as well as during spontaneous ventilation, such that cuff  110  remains substantially sealingly engaged to the trachea. The use of adjustable pressure valve  324  may minimize any air leakage from the higher tracheal airway pressure as compared to ambient pressure at the PEEP values that occur during expiration, as well as limit the upper PIP. Adjustable pressure valve  324  may be capable of separately adjusting the pressure inside cuff  110  during expiration and inspiration. Both adjustments may be made in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. Adjustment of adjustable pressure valve  324  may be achieved by positioning adjustment ring  222   a  and  222   b,  each of which may correspond to adjustment of either the inspiratory pressure or the expiratory pressure. Adjustment of pressure valve  324  may be achieved, for example, by turning adjustment ring  222   a  and  222   b  having, for example, an adjustable orifice (not shown).  
         [0045]     Referring to  FIG. 4A , depicted is a schematic diagram of a tracheal tube, according to another specific example embodiment of the present disclosure. In this embodiment, cuff  110  may be inflated by means of inflation tube  318  extending along cannula  102 . Tube  318  may be separate from cannula  102  (not shown), or tube  318  may be integrally formed with cannula  102 . Tube  318  is in communication with the interior of cuff  110  for inflation and deflation thereof, and the other end of tube  318  is in communication with connector  108 , thereby providing a passageway to inflate cuff  110 . Port  320  may be attached to connector  108  and is in communication with tube  318 . Port  320  may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  or to equalize the pressure in cuff  110  to ambient pressure. Port  320  may be adapted to receive a cap (not shown). Port  320  also may be used for attachment of a monitoring device or regulator, for example, an electronic or mechanical cuff pressure regulator (not shown) to, among other things, measure intracuff pressure. A separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at port  320  or integral with port  320 . Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0046]     Referring to  FIG. 4B , depicted is a schematic diagram of a tracheal tube, according to another specific example embodiment of the present disclosure. In this embodiment, an adjustable pressure valve  220  may be positioned distally to connector  108 , or integral to connector  108  (not shown), and in communication with cannula  102  and port  320 . In this way, adjustable pressure valve  220  may be placed so as to affect the pathway of air to cuff  110 . Such a pressure valve may help ensure that sufficient intracuff pressure is provided to cuff  110  and/or maintained in cuff  110  during IPPV, as well as during spontaneous ventilation, such that cuff  110  remains substantially sealingly engaged to the trachea. The use of a pressure valve may substantially minimize any air leakage from the higher tracheal airway pressure as compared to ambient pressure at the PEEP values that occur during expiration. In one aspect, adjustable pressure valve  220  may also act as a positive-pressure inflation valve, among other things, to limit the upper intracuff pressure during inspiration. In another aspect, a separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at port  320  or integral with port  320 . Adjustable pressure valve  220  may be adjusted in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. In addition, adjustable pressure valve  220  may be adjusted to help regulate, prevent, or allow air flow between tube  318  and port  320 . Adjustment of pressure valve  220  may be achieved, for example, by turning adjustment ring  222 . Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0047]     Referring to  FIG. 4C , depicted is a cross-sectional schematic diagram of a tracheal tube  100 , according to another specific example embodiment of the present disclosure. In this embodiment, cuff  110  (not shown) may be inflated by means of inflation tube  318  extending along cannula  102 . Tube  318  may be separate from cannula  102  (not shown), or tube  318  may be integrally formed with cannula  102 . Tube  318  is in communication with the interior of cuff  110  for inflation and deflation thereof, and the other end of tube  318  is in communication with connector  108 , thereby providing a passageway to inflate cuff  110 . Port  320   a  and  320   b  may be integral with flange  109 , or they may be separate from flange  109  (not shown). Port  320   a  may be attached to connector  108  and is in communication with tube  318 . Port  320   a  may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  or to equalize the pressure in cuff  110  to ambient pressure. Optionally, a pressure valve (not shown), for example, a fixed or adjustable pressure release valve, may be attached to port  320   a.  Port  320   a  and Port  320   b  may be adapted to receive cap  410   a  and  410   b,  respectively. Port  320   a  may be used for attachment of a monitoring device or regulator, for example, an electronic cuff pressure regulator (not shown) to, among other things, measure intracuff pressure. Port  320   b  also may be used for attachment of a monitoring device, for example, an anesthesia gas monitoring unit (not shown) to, among other things, monitor end-tidal CO 2 . Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0048]     An adjustable pressure valve  220  may be positioned distally to connector  108  (not shown), or integral to connector  108 , and in communication with cannula  102  and port  320   a.  In this way, adjustable pressure valve  220  may be placed so as to affect the pathway of air to cuff  110 . In one aspect, adjustable pressure valve  220  may also act as a positive-pressure inflation valve, among other things, to limit the upper intracuff pressure during inspiration. In another aspect, a separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at port  320   a  or integral with port  320   a.  Adjustable pressure valve  220  may be adjusted in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. In addition, adjustable pressure valve  220  may be adjusted to help regulate, prevent, or allow air flow between tube  318  and port  320   a.  Adjustment of pressure valve  220  may be achieved, for example, by turning adjustment ring  222  having, for example, an adjustable orifice  420 . For fully deflating cuff  110  (e.g., for extubation), the adjustment ring  222  may be positioned to close orifice  420  and a syringe, for example, may be affixed to port  320   a  to manually deflated cuff  110 .  
         [0049]     Referring to  FIG. 4D , depicted is a schematic diagram of a tracheal tube  100 , according to another specific example embodiment of the present disclosure. In this embodiment, cuff  110  (not shown) may be inflated by means of inflation tube  318  extending along cannula  102 . Tube  318  may be separate from cannula  102  (not shown), or tube  318  may be integrally formed with cannula  102 . Tube  318  is in communication with the interior of cuff  110  for inflation and deflation thereof, and the other end of tube  318  is in communication with connector  108 , thereby providing a passageway to inflate cuff  110 . Port  320   a  may be integral with flange  109 , or separate from flange  109  (not shown). Port  320   a  may be attached to cannula  102  and is in communication with tube  318 . Port  320   a  may be selectively openable and provide a means to access cuff  110 , for example, to inflate or deflate cuff  110  or to equalize the pressure in cuff  110  to ambient pressure. Optionally, a pressure release valve  330 , which may be fixed or adjustable, may be attached to port  320   a.  In another aspect, a separate positive pressure inflation valve (not shown), which may be adjustable or fixed, may be added to tracheal tube  100 , for example, at port  320   a  or integral with port  320   a.  Port  320   a  may be adapted to receive a cap (not shown). Port  320   a  may be used for attachment of a monitoring device or regulator, for example, an electronic cuff pressure regulator (not shown). Integral with connector  108  is HME filter  430  in communication with the lumen of cannula  102 . Port  320   b  on HME filter  430  may be selectably openable and used for, among other things, attachment of a monitoring device (not shown).  
         [0050]     An adjustable pressure valve  220  may be positioned distally to cannula  102 , and in communication with cannula  102  and port  320   a.  In this way, adjustable pressure valve  220  may be placed so as to affect the pathway of air to cuff  110 . In one aspect, adjustable pressure valve  220  may also act as a positive-pressure inflation valve, among other things, to limit the upper intracuff pressure during inspiration. Adjustable pressure valve  220  may be adjusted in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. In addition, adjustable pressure valve  220  may be adjusted to help regulate, prevent, or allow air flow between tube  318  and port  320   a.  Adjustment of pressure valve  220  may be achieved, for example, by turning adjustment ring  222  having, for example, an adjustable orifice  420 . For fully deflating cuff  110  (e.g., for extubation), the adjustment ring  222  may be positioned to close orifice  420  and a syringe, for example, may be affixed to port  320   a  to manually deflated cuff  110 .  
         [0051]     Referring to  FIG. 5 , depicted is a schematic diagram of a tracheal tube, according to another specific example embodiment of the present disclosure. In this embodiment, cuff  110  may be inflated by passageway for air formed by one or more of tube  118 , pilot balloon  116 , cuff connector site  114 , adjustable regulator  520 , regulator tube  518 , and port  320 . Tube  118  may be separate from cannula  102 , or tube  118  may be integrally formed with the wall of cannula  102  (not shown). Tube  118  is in communication with the interior of cuff  110  for inflation and deflation thereof, and the other end of tube  118  may be adapted to receive pilot balloon  116 . Alternatively, tube  118  may be integrally formed with pilot balloon  116 , for example, by expanding tube  118  into a balloon shape having sufficient compliance. Pilot balloon  116  may be in communication with cuff connector site  114 , which may be located on adjustable regulator  520 . Cuff connector site  114  may be adapted to receive pilot balloon  116  and may communicate with adjustable regulator  520 . Tracheal tube  100  also may include an HME filter (not shown). Such an HME filter may be in communication with the lumen of cannula  102 , for example, integral to connector  108  or attached to connector  108 .  
         [0052]     Adjustable regulator  520  may also communicate with regulator tube  518 , and regulator tube  518  may communicate with port  320 . In this way, adjustable regulator  520  may be placed so as to affect the pathway of air to cuff  110 . Port  320  may be attached to connector  108  and be in communication with an air supply (not shown). Port  320  may be selectively openable and provide access to cuff  110 , for example, to inflate or deflate cuff  110 . Port  320  may also be used for attachment of a monitoring device or regulator, for example, an electronic or mechanical cuff pressure regulator.  
         [0053]     Adjustable regulator  520  may help ensure that sufficient intracuff pressure is provided to cuff  110  during IPPV, as well as during spontaneous ventilation, such that cuff  110  remains substantially sealingly engaged to the trachea. The use of a regulator may minimize any air leakage from the higher tracheal airway pressure as compared to ambient pressure at the PEEP values that occur during expiration, as well as limit the upper PIP. Adjustable regulator  520  may be capable of separately adjusting the pressure inside cuff  110  during expiration and inspiration. Both adjustments may be made in a range from about a value corresponding to approximately the PEEP to about a value corresponding to approximately the PIP. Adjustment of adjustable regulator  520  may be achieved by positioning inspiration controller  530  and expiration controller  540 .  
         [0054]     While embodiments of this disclosure have been depicted, described, and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and are not exhaustive of the scope of the disclosure.