Patent Publication Number: US-2020289780-A1

Title: Connectors for respiratory assistance systems

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/511,093, filed Mar. 14, 2017, which is a U.S. National Phase of International Patent Application No. PCT/NZ2015/050151, filed Sep. 17, 2015, which claims the priority benefit of U.S. Provisional Application No. 62/051,860, filed Sep. 17, 2014, the entirety of which is hereby incorporated by reference herein. Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure generally relates to respiratory assistance systems. More particularly, the present disclosure relates to conduit connectors for respiratory assistance systems. 
     Description of the Related Art 
     A respiratory assistance system may be used to provide respiratory gases to a patient from a gases source via an inspiratory conduit in fluid communication between the gases source and a patient interface. Examples of a patient interface may include an oral mask, a nasal mask, a nasal cannula, a tracheal mask, or an endotracheal tube. In a respiratory assistance system where the gases source is a ventilator, gases exhaled by the patient into the patient interface may be returned via an expiratory conduit in fluid communication between the patient interface and the ventilator. The inspiratory conduit and the expiratory conduit may be connected to the patient interface via a wye-piece. 
     A respiratory assistance system may include a humidification device to condition respiratory gases provided to the patient. The humidification device may include a humidification chamber containing liquid and a heater adjacent the humidification chamber to heat the liquid to produce vapor. The humidification device may be positioned in the fluid communication path between the gases source and the patient interface to heat and/or humidify respiratory gases prior to delivery via the inspiratory conduit to the patient interface. Respiratory gases delivered to a patient at 100% relative humidity and 37° C. mimic the properties resulting from the transformation of air that occurs as it passes through the patient&#39;s nose to the lungs. This promotes efficient gas exchange and ventilation in the lungs, aids defense mechanisms in the airway, and increases patient comfort during treatment. 
     An inspiratory conduit for use in a respiratory assistance system with a humidification device may include a heating component, such as a heater wire, to keep heated and humidified respiratory gases delivered via the inspiratory conduit to the patient interface warm and to reduce formation of condensate in the inspiratory conduit. However, a heated inspiratory conduit may be connected to an unheated wye-piece and/or an unheated patient interface. The passage of heated and humidified respiratory gases through an unheated wye-piece and/or an unheated patient interface can increase formation of condensate in the respiratory assistance system. Vapor present in gases exhaled by a patient can also increase formation of condensate in a respiratory assistance system. 
     SUMMARY 
     Condensate that forms in a respiratory assistance system may drain in one or more of three directions: toward the patient, into the inspiratory conduit toward the humidification device, and/or into the expiratory conduit toward the ventilator. Condensate that drains toward the patient may reduce effectiveness of respiratory treatment and/or decrease patient comfort. Thus, caregivers often may arrange the inspiratory conduit, the expiratory conduit, and/or the patient interface to reduce the amount of condensate that drains toward the patient. Condensate that drains toward the humidification device may cause at least partial occlusion of the inspiratory conduit which could reduce effective of respiratory treatment. Condensate that drains toward the ventilator may damage the ventilator. 
     In a respiratory assistance system where the expiratory conduit includes features adapted to reduce condensate in gases delivered via the expiratory conduit to a gases source, it may be useful to decrease the proportion of condensate that drains toward the patient and/or into the inspiratory conduit by increasing the proportion of condensate that drains into the expiratory conduit. Embodiments are disclosed of connectors configured to at least decrease the proportion of condensate that drains into the inspiratory conduit by causing the portion of the wye-piece connected to the expiratory conduit to be positioned below the portion of the wye-piece connected to the inspiratory conduit. This arrangement allows condensate that reaches the wye-piece to naturally drain through gravitational force into the expiratory. 
     According to an embodiment, a connector comprises a wye-piece, the wye-piece comprising a port for an inspiratory conduit, a port for an expiratory conduit, a port for a patient interface, a body formed by a fluid passageway between the port for the inspiratory conduit and the port for the patient interface and a fluid passageway between the port for the expiratory conduit and the port for the patient interface, and a ball for connecting the wye-piece to a medical stand, wherein the ball is attached to the body adjacent the port for the inspiratory conduit such that when the ball is connected to a medical stand, the port for the expiratory conduit is positioned below the port for the inspiratory conduit. 
     The ball may be attached directly to the body of the wye-piece, or it may be attached to a stem that is attached to the body of the wye-piece. The ball, or ball and stem, may be integrally formed with the body, detachable from the body, or formed separately from and securely adhered to the body. 
     According to an another example embodiment, a connector comprises a circuit hanger, the circuit hanger comprising a body, the body comprising a cradle for an inspiratory conduit, a cradle for an expiratory conduit, and a ball for connecting the circuit hanger to a medical stand, wherein the ball is attached to the body adjacent the cradle for the inspiratory conduit such that when the ball is connected to a medical stand, the cradle for the expiratory conduit is positioned below the cradle for the inspiratory conduit. 
     The ball may be attached directly to the body of the circuit hanger, or it may be attached to a stem that is attached to the body of the circuit hanger. The ball, or ball and stem, may be integrally formed with the body, detachable from the body, or formed separately from and securely adhered to the body. 
     The medical stand may be configured to securely hold the ball of the connector so that the connector may be held in a specific orientation or position. The medical stand may have a mechanism that allows the orientation or position of the connector to be changed by a user. The medical stand may have a ball-holding portion that is configured to attach to, hold, or secure the ball of a connector that comprises a circuit hanger. The ball-holding portion may be able to be tightened or loosened so that a user may change the orientation or position of the connector, such as by first loosening the ball-holding portion, changing the orientation or position of the connector to the desired orientation or position, and then tightening the ball-holding portion to secure the connector in the desired orientation or position. 
     According to an another example embodiment, a connector comprises a coaxial wye-piece, the coaxial wye-piece comprising a body, the body comprising an inspiratory branch with an inspiratory conduit port, an expiratory branch with an expiratory conduit port, a patient end with a patient interface port, a fluid passageway between the inspiratory conduit port and the patient interface port, and a fluid passage between the expiratory conduit port and the patient interface port. The inspiratory branch may comprise a tip that extends into the fluid passageway between the expiratory conduit port and the patient interface port of the body. The tip of the inspiratory branch may comprise a lip, the lip configured to obstruct or impede a condensate from draining toward the inspiratory branch. An MDI or pressure port may also be located on the inspiratory branch at a location far enough away from the inspiratory conduit port so that the inspiratory conduit port may be connected to an inspiratory conduit. The patient end may have a solid wall between an inner surface and an outer surface, as well as a dual taper design that allows the patient end to act as a male or female connector. 
     According to an another example embodiment, a connector comprises a coaxial wye-piece, the coaxial wye-piece comprising a body, the body comprising an inspiratory branch with an inspiratory conduit port, an expiratory branch with an expiratory conduit port, a patient end with a patient interface port, a fluid passageway between the inspiratory conduit port and the patient interface port, and a fluid passage between the expiratory conduit port and the patient interface port. The inspiratory branch may comprise a tip that extends into the fluid passageway between the expiratory conduit port and the patient interface port of the body. The tip of the inspiratory branch may comprise a lip, the lip configured to obstruct or impede a condensate from draining toward the inspiratory branch. An MDI or pressure port may also be located on the inspiratory branch at a location far enough away from the inspiratory conduit port so that the inspiratory conduit port may be connected to an inspiratory conduit. The patient end may have a gap in a wall between an inner surface and an outer surface, as well as a dual taper design that allows the patient end to act as a male or female connector. The gap may preserve the dual taper design while allowing less material to be used. 
     According to an another example embodiment, a connector comprises a coaxial wye-piece, the coaxial wye-piece comprising a body, the body comprising an inspiratory branch with an inspiratory conduit port, an expiratory branch with an expiratory conduit port, a patient end with a patient interface port, a fluid passageway between the inspiratory conduit port and the patient interface port, and a fluid passage between the expiratory conduit port and the patient interface port. The body may further comprise an inner coaxial inspiratory tube that extends from the inspiratory branch into the fluid passageway between the expiratory conduit port and the patient interface port. The inner coaxial inspiratory tube may be directed towards the patient end and may extend all up to the patient interface port of the patient end. The inner coaxial inspiratory tube may obstruct or impede a condensate from draining toward the inspiratory branch, and it may also direct the flow of inspiratory gas towards the patient end. The inspiratory branch may comprise a tip that extends into the fluid passageway between the expiratory conduit port and the patient interface port of the body. The tip of the inspiratory branch may comprise a lip, the lip configured to obstruct or impede a condensate from draining toward the inspiratory branch. An MDI or pressure port may also be located on the inspiratory branch at a location far enough away from the inspiratory conduit port so that the inspiratory conduit port may be connected to an inspiratory conduit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects of the present disclosure will be described with reference to the following drawings, which should be considered illustrative but not limiting. 
         FIG. 1  is a diagram of an example respiratory assistance system that may be used to provide respiratory gases to a patient. 
         FIG. 2  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a wye-piece. 
         FIG. 3A  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a circuit hanger. 
         FIG. 3B  is a diagram of a ball-holding end of a medical stand that may be attached to a connector for a respiratory assistance system that comprises a circuit hanger. 
         FIG. 3C  is a diagram of a medical stand that may be attached to a connector for a respiratory assistance system that comprises a circuit hanger. 
         FIG. 4  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
         FIG. 5A  is a diagram illustrating a perspective side view of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
         FIG. 5B  is a diagram illustrating a side cut-away view of a connector for a respiratory assistance system according to the example embodiment of  FIG. 5A  in which the connector comprises a coaxial wye-piece. 
         FIG. 6  is a diagram illustrating a cut-away view of the geometry and positioning of features of a connector for a respiratory assistance system in which the connector comprises a coaxial wye-piece. 
         FIG. 7A  is a diagram of where an MDI port may be located on a connector in a respiratory assistance system in which the connector comprises a coaxial wye-piece. 
         FIG. 7B  is a diagram illustrating a connector for a respiratory assistance according to an example embodiment in which the connector comprises a coaxial wye-piece with an MDI port. 
         FIG. 8A  is a diagram illustrating a cross-section view of the dimensions and lengths of a connector for a respiratory assistance system in which the connector comprises a coaxial wye-piece. 
         FIG. 8B  is a diagram illustrating a cross-section view of the dimensions and angles of a connector for a respiratory assistance system in which the connector comprises a coaxial wye-piece. 
         FIG. 9  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
         FIG. 10  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
         FIG. 11  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
         FIG. 12  is a diagram of a connector for a respiratory assistance system according to an example embodiment in which the connector comprises a coaxial wye-piece. 
     
    
    
     DETAILED DESCRIPTION 
     Terms 
     The term conduit refers to any tube, channel, or passageway that may be used in a respiratory assistance system. Conduits that may be used to carry respiratory gas in a respiratory assistance system include smooth-bore conduits, which may have inner wall surfaces that are smooth. The width of the conduit wall of a smooth-bore conduit may be constant. An example of a smooth-bore conduit is disclosed in International Application No. PCT/NZ2015/050028, which is herein incorporated by reference in its entirety. Conduits that may be used to carry respiratory gas in a respiratory assistance system may also include conduits with inner wall surfaces that are not smooth. Examples of such conduits include corrugated conduits. A corrugated conduit may have a series of parallel ridges or grooves. A corrugated conduit may also be known as a concertina or bellows conduit. Other types of conduits with inner wall surfaces that are not smooth may have helical or spiraling ridges or grooves. A conduit may be designed to possess a combination of features from different conduit types. For example, a conduit may have a smooth bore while retaining a series of parallel ridges or grooves on the exterior of the conduit. Such a conduit would have a smooth inner wall surface and a wall width that is non-constant while retaining some of the benefits of a corrugated conduit, which are described in further detail below. 
     There may be certain benefits associated with a corrugated conduit. For example, the sizing and/or spacing of parallel ridges or grooves in a corrugated conduit may allow for specially-designed medical connectors that fit the ridges and grooves in order to hold or grasp the corrugated conduit in place. A corrugated conduit may allow for increased flexibility and bending. The parallel ridges or grooves present in a corrugated conduit may trap or hinder mobile condensate, making a corrugated conduit well-suited for preventing condensate from freely moving in a respiratory assistance system. 
     There may be certain benefits associated with the use of smooth-bore conduits. The smooth inner wall surface of smooth-bore conduits may allow for the flow of gas with less resistance and reduced turbulence. The smooth inner wall surface of smooth-bore conduits may allow for higher velocity gas flow. This may make smooth-bore conduits well-suited for high flow respiratory therapy. A connector designed to reduce the mobility of condensate within a respiratory assistance system may greatly improve the usability of the system with a smooth-bore conduit. 
     The term branch refers to a projection of a connector in a respiratory assistance system. For example, a connector may have a Y-shape. One end of this connector may be referred to as the inspiratory branch because it is designed to connect to, and interface with, the inspiratory conduit. Another end of this connector may be referred to as the expiratory branch because it is designed to connect to, and interface with, the expiratory conduit. A branch may have a port or opening in it which may allow the branch to be fluidly connected to another object. For example, an inspiratory branch may have an inspiratory conduit port for connecting to the inspiratory conduit and an expiratory branch may have an expiratory conduit port for connecting to the expiratory conduit. 
     The term metered-dose inhaler (MDI) port refers to a port in a respiratory assistance system that is configured to connect to, or interface with, a metered-dose inhaler, which is a device designed to deliver a specific amount of medication to the lungs of a patient. A metered-dose inhaler may be configured to deliver medication in aerosol form through the MDI port into the inspiratory gas flow of a respiratory assistance system. 
     General Respiratory Assistance System (FIG.  1 ) 
       FIG. 1  is a diagram of an example respiratory assistance system  100  that may be used to provide respiratory gases to a patient  101 . The respiratory assistance system  100  comprises a gases source  105  in fluid communication with a patient interface  115  via an inspiratory conduit  103  and an expiratory conduit  117 . In some configurations, the gases source  105  comprises a ventilator. The inspiratory conduit  103  and the expiratory conduit  117  are connected to the patient interface  115  via a wye-piece  113 . 
     In the configuration shown, the respiratory assistance system  100  also comprises a humidification device  107  to condition respiratory gases provided to the patient  101 . The humidification device  107  is positioned in the fluid communication path between the gases source  105  and the patient interface  115  to heat and/or humidify respiratory gases prior to delivery via the inspiratory conduit  103  to the patient interface  115 . The humidification device  107  comprises a humidification chamber  129  containing a liquid  130  and a heater  131  adjacent to the humidification chamber  129  to heat the liquid  130  to produce vapor that humidifies respiratory gases passing over the liquid  130 . In some configurations, the gases source  105  and the humidification device  107  are located within a common housing and/or comprise components of a single apparatus. In some configurations, the gases source  105  is connected directly to the patient interface  115  via the inspiratory conduit  103  with no intervening humidification device. 
     In some configurations, the inspiratory conduit  103  includes a heating component, such as a heater wire, to keep heated and humidified respiratory gases delivered via the inspiratory conduit  103  to the patient interface  115  warm and to reduce formation of condensate in the inspiratory conduit  103 . In some configurations, the wye-piece  113  and/or the patient interface  115  might not include a similar heating feature, so vapor present in heated and humidified respiratory gases delivered via the inspiratory conduit  103  to the wye-piece  113  may condense in the wye-piece  113  and/or the patient interface  115 . In some configurations, vapor present in gases exhaled by the patient  101  may condense in the wye-piece  113  and/or the patient interface  115 . 
     Condensate that forms in the respiratory assistance system  100 , particularly but not exclusively in the wye-piece  113  and/or the patient interface  115 , may drain in one or more of three directions: toward the patient  101 , into the inspiratory conduit  103  toward the humidification device  107 , and/or into the expiratory conduit  117  toward the gases source  105 . It may be considered undesirable to allow condensate to drain toward the patient  101 , because liquid introduced to the face or airway of the patient  101  may reduce effectiveness of respiratory treatment and/or decrease comfort. It may be considered undesirable to allow condensate to drain toward the humidification device  107 , because condensate formed of vapor present in gases exhaled by the patient may cause at least partial occlusion of the inspiratory conduit  103  which could reduce effective of respiratory treatment. It may be considered undesirable to allow condensate to drain toward the gases source  105 , because liquid may damage the gases source  105 . 
     In some configurations, the expiratory conduit  117  may include features configured to reduce condensate in gases delivered through the expiratory conduit  117  to the gases source  105 . See, for example, the embodiments and features disclosed in U.S. Patent Application Publication No. 2013/0098360. In some configurations, it may be appropriate to decrease the proportion of condensate that drains toward the patient  101  and into the inspiratory conduit  103  by increasing the proportion of condensate that drains into the expiratory conduit  117 . Multiple embodiments of connectors are disclosed that at least decrease the proportion of condensate that drains into the inspiratory conduit  103  by causing the portion of the wye-piece  113  connected to the expiratory conduit  117  to be positioned below the portion of the wye-piece  113  connected to the inspiratory conduit  103 . Other embodiments of connectors are disclosed that at least decrease the proportion of condensate that drains into the inspiratory conduit  103  regardless of the orientation or positioning of the inspiratory conduit  103  relative to the expiratory conduit  117 . 
     Wye-Piece Connector With Ball (FIG.  2 ) 
       FIG. 2  is a picture of a connector for the respiratory assistance system  100  according to a first example embodiment, where the connector comprises a wye-piece  200 . The wye-piece  200  comprises a body  210 , an inspiratory conduit port  225 , an expiratory conduit port  220 , and a patient interface port  215 . The body  210  includes a fluid passageway between the inspiratory conduit port  225  and the patient interface port  215  and a fluid passageway between the expiratory conduit port  220  and the patient interface port  215 . The wye-piece  200  comprises a ball  205  for connecting the wye-piece  200  to a medical stand. The ball  205  is attached to the body  210  adjacent the inspiratory conduit port  225  such that when the ball  205  is connected to a medical stand, the expiratory conduit port  220  is positioned below the inspiratory conduit port  225 . 
     In the configuration shown, the ball  205  is attached to a stem  230  and the stem  230  is attached to the body  210 . The ball  205  may be integrally formed with the stem  230 . The ball  205  may be detachable from the stem  230 . The ball  205  may be formed separately from and securely adhered to the stem  230 . The stem  230  may be integrally formed with the body  210 . The stem  230  may be detachable from the body  210 . The stem  230  may be formed separately from and securely adhered to the body  210 . Any combination of the above types of attachment between the ball  205  and the stem  230  and between the stem  230  and the body  210  may be used. 
     In some configurations, the ball  205  is attached directly to the body  210 . The ball  205  may be integrally formed with the body  210 . The ball  205  may be detachable from the body  210 . The ball  205  may be formed separately from and securely adhered to the body  210 . 
     In use, the wye-piece  113  is replaced by the wye-piece  200 , such that the inspiratory conduit  103  is connected to the inspiratory conduit port  225 , the expiratory conduit  117  is connected to the expiratory conduit port  220 , and the patient interface  115  is connected to the patient interface port  215 . In use, the wye-piece  200  is connected, via the ball  205 , to a medical stand, which positions the expiratory conduit port  220  below the inspiratory conduit port  225 , which causes the expiratory conduit  117  to be positioned below the inspiratory conduit  103 , at least causing a larger proportion of any condensate formed in the respiratory assistance system  100  that reaches the wye-piece  200  to drain into the expiratory conduit  117  than into the inspiratory conduit  103 . 
     Circuit Hanker Connector With Ball (FIG.  3 A) 
       FIG. 3A  is a picture of a connector for the respiratory assistance system  100  according to a second example embodiment, where the connector comprises a circuit hanger  127 . The circuit hanger  127  includes a body  310 , and the body  310  includes an inspiratory conduit cradle  325  and an expiratory conduit cradle  320 . The circuit hanger  127  comprises a ball  305  for connecting the circuit hanger  127  to a medical stand. The ball  305  is attached to the body  310  adjacent the inspiratory conduit cradle  325  such that when the ball  305  is connected to a medical stand, the expiratory conduit cradle  320  is positioned below the inspiratory conduit cradle  325 . 
     In the configuration shown, the ball  305  is attached to a stem  330  and the stem  330  is attached to the body  310 . The ball  305  may be integrally formed with the stem  330 . The ball  305  may be detachable from the stem  330 . The ball  305  may be formed separately from and securely adhered to the stem  330 . The stem  330  may be integrally formed with the body  310 . The stem  330  may be detachable from the body  310 . The stem  330  may be formed separately from and securely adhered to the body  310 . Any combination of the above types of attachment between the ball  305  and the stem  330  and between the stem  330  and the body  310  may be used. 
     In some configurations, the ball  305  is attached directly to the body  310 . The ball  305  may be integrally formed with the body  310 . The ball  305  may be detachable from the body  310 . The ball  305  may be formed separately from and securely adhered to the body  310 . 
     Referring again to  FIG. 1 , the circuit hanger  127  is shown connected to the inspiratory conduit  103  and the expiratory conduit  117 , such that the inspiratory conduit  103  passes through, or is held by, the inspiratory conduit cradle  325  and the expiratory conduit  117  passes through, or is held by, the expiratory conduit cradle  320 . In use, the circuit hanger  127  is connected, via the ball  305 , to a medical stand, which positions the expiratory conduit cradle  320  below the inspiratory conduit cradle  325 , which causes the expiratory conduit  117  to be positioned below the inspiratory conduit  103 , at least causing a larger proportion of any condensate formed in the respiratory assistance system  100  that reaches the wye-piece  113  to drain into the expiratory conduit  117  than into the inspiratory conduit  103 . 
     In some configurations, the inspiratory conduit cradle  325  may include a shape suitable for holding the inspiratory conduit  103  that is different from the shape of the inspiratory conduit cradle  325  depicted in  FIG. 3A . In some configurations, the expiratory conduit cradle  320  may include a shape suitable for holding the expiratory conduit  117  that is different from the shape of the expiratory conduit cradle  320  depicted in  FIG. 3A . In a preferred configuration, the inspiratory conduit cradle  325  may include a different shape from the expiratory conduit cradle  320 , which may help ensure that the connections are correct, i.e. the inspiratory conduit  103  is connected to the inspiratory conduit cradle  325  and the expiratory conduit  117  is connected to the expiratory conduit cradle  320 . In some configurations, the inspiratory conduit cradle  325  and the expiratory conduit cradle  320  may include the same shape. 
     In some configurations, the inspiratory conduit cradle  325  may be adapted to connect to a circuit accessory that is adapted to attach to the inspiratory conduit  103 . In some configurations, the expiratory conduit cradle  320  may be adapted to connect to a circuit accessory that is adapted to attach to the expiratory conduit  117 . For example, but without limitation, either or both of the inspiratory conduit cradle  325  or the expiratory conduit cradle  320  may be adapted to connect to any one or more of the locking clips disclosed in U.S. Patent Application Publication No. 2014/0236041. In a preferred configuration, the inspiratory conduit cradle  325  is adapted to connect to a different type of circuit accessory from a type of circuit accessory to which the expiratory conduit cradle  320  is adapted to connect, which may help ensure that the inspiratory conduit  103  is connected to the inspiratory conduit cradle  325  and the expiratory conduit  117  is connected to the expiratory conduit cradle  320 . In some configurations, the inspiratory conduit cradle  325  and the expiratory conduit cradle  320  are adapted to connect to the same type of circuit accessory. 
     In some configurations, the body  310  may be adapted to connect to a circuit accessory that is adapted to attach to both the inspiratory conduit  103  and to the expiratory conduit  117  in such a way that when the ball  305  is connected to a medical stand, the expiratory conduit  117  is positioned below the inspiratory conduit  103 . For example, but without limitation, the body  310  may be adapted to connect to any one or more of the locking clips disclosed in U.S. Patent Application Publication No. 2014/0236041 that is engageable with multiple tubes. 
     Medical Stand to Secure Ball (FIGS.  3 B and  3 C) 
       FIG. 3B  is a diagram of a ball-holding end  350  of a medical stand that may be attached to a connector for a respiratory assistance system that comprises a circuit hanger. The ball-holding end  350  of the medical stand is attached to an arm  355 . The arm  355  may be a flexible arm that allows the ball-holding end  350  to be positioned and oriented by a user. 
     The ball-holding end  350  has a first clamp  365  and a second clamp  370 . The first clamp  365  and the second clamp  370  have a hole in which a screw  375  may be disposed. The screw  375  may be mated with a handle  360 . The handle  360  may have threads such that rotating the handle in one direction will bring the first clamp  365  and a second clamp  370  closer together, while rotating the handle in another direction will bring the first clamp  365  and the second clamp  370  further apart. The connector may have a ball  335  that may be held within the jaws of the first clamp  365  and the second clamp  370 . By bringing the first clamp  365  and the second clamp  370  closer together, the ball  335  and the connector may be held in a specific orientation or position. By bringing the first clamp  365  and the second clamp  370  further apart, the ball  335  may be loosened from the grip of the first clamp  365  and the second clamp  370  enough that the orientation or position of the ball  335  and the connector may be changed. 
     However, the ball-holding end  350  may not necessarily be configured to tighten or loosen so that the orientation or position of the connector may be changed. Instead, a different mechanism may be used to attach to, hold, or secure the ball  335  of the connector. 
       FIG. 3C  is a diagram of a medical stand that may be attached to a connector for a respiratory assistance system that comprises a circuit hanger. It has a ball-holding end attached to the arm  355 , with the ball-holding end having a first clamp  365  and a second clamp  370 . A handle  360  is mated to a screw (not shown) running through the first clamp  365  and the second clamp  370 . The first clamp  365  and the second clamp  370  securely hold the ball  335  of a connector. 
     The medical stand also has additional features which allow the orientation and positioning of the ball-holding end and, by extension, the ball  335  and connector, to be changed and fixed as desired. The arm of the medical stand may be articulated at various joints. For example, there is a handle  380 A attached to a joint  385 A. The handle  380 A may be rotated in order to tighten or loosen the joint  385 A. Loosening the joint  385 A may allow the arm of the medical stand to be articulated at joint  385 A. The arm of the stand may then be rotated into a desired orientation or position for the joint  385 A to be tightened, after which the arm will be secured in its new desired orientation or position. Similarly, there may be a handle  380 B for controlling a joint  385 B, a handle  380 C for controlling a joint  385 C, and so forth. 
     Coaxial Wye-Piece Connector (FIG.  4 ) 
       FIG. 4  illustrates a connector for the respiratory assistance system  100  according to a third example embodiment, where the connector includes a coaxial wye-piece  400 . 
     The coaxial wye-piece  400  has a smooth inner wall surface, so that it has a similar resistance to flow as other wye-piece connectors, such as the wye-piece  113  shown in 
       FIG. 1 . The coaxial wye-piece  400  may be a single-use wye-piece or a reusable wye-piece. The coaxial wye-piece  400  may be configured to work with various types of conduits, such as smooth-bore conduits, in order to reduce the amount of condensate entering the inspiratory conduit  103  during invasive or non-invasive ventilation. 
     The coaxial wye-piece  400  has an inspiratory branch  405  that connects to, or interfaces with, the inspiratory conduit  103 . Respiratory gases from the inspiratory conduit  103  flow into the coaxial wye-piece  400  through the inspiratory branch  405 . The orientation of the inspiratory branch  405  directs respiratory gases from the inspiratory conduit  103  towards the patient  101 . The respiratory gases flows towards a patient end  415  of the coaxial wye-piece  400 , where it may travel through the patient interface  115  before being breathed in by the patient  101 . 
     Once the patient  101  exhales, the exhaled gases may enter the coaxial wye-piece  400  through the patient end  415 . The exhaled gas will flow towards an expiratory branch  410  of the coaxial wye-piece  400 , which connects to, or interfaces with, the expiratory conduit  117 . The coaxial wye-piece  400  provides a straight path from the patient end  415  to the expiratory branch  410 . A lip or extension  420  prevents or obstructs condensate in the exhaled gas from entering the inspiratory branch  405  and the inspiratory conduit  103 . This decreases the proportion of condensate that drains into the inspiratory conduit  103  regardless of the orientation or positioning of the inspiratory conduit  103  relative to the expiratory conduit  117 . The condensate is directed towards the expiratory conduit  117 . 
     The diameter of the inspiratory branch  405  narrows from the conduit interface end of inspiratory branch  405  to the lip  420 . The narrowing of the diameter near the lip  420  causes the respiratory gas that flows into the coaxial wye-piece  400  through the inspiratory branch  405  to move faster as the diameter narrows based on Pouseuille&#39;s Law. This increased speed of gas flow may discourage or prevent condensate from traveling against the flow direction and entering the inspiratory branch  405 , thereby keeping condensate out of the attached inspiratory conduit  103 . 
     A solid wall  425  on the patient end  415  of the coaxial wye-piece  400  has a dual taper design, so that the patient end  415  may act as a female or male connector. There is a taper on the outside surface of the solid wall  425  so that the patient end  415  may act as a male connector. For example, the patient end  415  may be configured to have a  22  mm male connection to fit into a standard  22  mm female taper. There is a taper on the inner surface of the solid wall  425  so that the patient end  415  may act as a female connector. For example, the patient end  415  may be configured to have a  15  mm female connection for connecting to a  15  mm male taper of a trachea mount, the patient interface  115 , and so forth. Other embodiments of the coaxial wye-piece  400  for which the wall of the patient end  415  is not a solid wall, such as the solid wall  425 , but still maintains the dual taper design is described below with regard to  FIGS. 5A and 5B . 
     The solid wall  425  may be further configured or designed to meet desired commercial goals. Making the solid wall  425  as thin as possible may aid in the manufacturing of the wye-piece  400 . For example, if the wye-piece  400  is injection moulded then having the solid wall  425  as thin as possible will reduce the time needed for the wye-piece  400  to cool and improve the moulding stability of tapered portions of the solid wall  425 . A thin embodiment of the solid wall  425  will also reduce the amount of material (such as plastic) needed to produce the wye-piece  400 , which results in lower unit costs and shorter manufacturing times. 
     The coaxial wye-piece  400  drains condensate to the expiratory branch  410  regardless of the orientation of the coaxial wye-piece  400 . In a scenario where the orientation of the coaxial wye-piece  400  has the inspiratory branch  405  pointed downwards towards the ground with no flow coming from the inspiratory branch  405 , it will be unlikely that condensate flows into the inspiratory branch  405 . The lip  420  prevents condensate from entering the inspiratory branch  405  in such an orientation. In more common scenarios where the inspiratory branch  405  is not pointed downwards, any condensate that splashes into the inspiratory branch  405  falls back down into the straight flow path between the patient end  415  and the expiratory branch  410 . The design of the coaxial wye-piece  400  allows condensate to be kept out of the inspiratory conduit  103  for seven days or more, in comparison to some wye-piece designs in which condensate may be found in the inspiratory conduit  103  within six hours of use. Furthermore, the design of the coaxial wye-piece  400  provides these benefits without greatly increasing the resistance to flow of respiratory gases passing through any portion of the wye-piece  400 . In particular, there may be little change to the resistance to flow between the patient end  415  and the expiratory branch  410  in comparison to other wye-piece designs. The flow path between the patient end  415  and the expiratory branch  410  is a straight path in which the lip  420  creates a relatively minor obstruction to flow. 
     By being able to function in different orientations, the coaxial wye-piece  400  allows the respiratory assistance system  100  to be simple to set up and use effectively by taking the orientation of the coaxial wye-piece  400  out of consideration during setup. Thus, the coaxial wye-piece  400  may be particularly useful in reusable respiratory assistance systems, which may have breathing circuits that are not preassembled and more prone to user error in circuit setup. The coaxial wye-piece  400  may also be particularly suitable for use at home. 
     Coaxial Wye-Piece Connector With Gap (FIGS.  5 A and  5 B) 
       FIGS. 5A and 5B  both show a connector for the respiratory assistance system  100  according to an example embodiment where the connector includes a coaxial wye-piece  500 .  FIG. 5A  illustrates a perspective view of the coaxial wye-piece  500  while  FIG. 5B  illustrates a side cutaway view of the same coaxial wye-piece  500 . 
     The coaxial wye-piece  500  is very similar in design and operation to the coaxial wye-piece  400  described above in reference to  FIG. 4 . For example, the coaxial wye-piece  500  also has an inspiratory branch  505 , an expiratory branch  510 , and a patient end  515 . Observable in  FIG. 5B  is a lip  520  which is similar to the lip  420  shown in the embodiment of  FIG. 4 . The main difference between the embodiments is that the coaxial wye-piece  500  has a wall gap  525 , whereas the coaxial wye-piece  400  from  FIG. 4  has the solid wall  425 . Instead of the solid wall  425  between the inner surface and the outer surface of the patient end  415  of the coaxial wye-piece  400 , the coaxial wye-piece  500  has the wall gap  525  that separates the inner surface and the outer surface of the patient end  515 . 
     Normally in a reusable circuit, the presence of the wall gap  525  may act as a dirt trap which may make the wye-piece connector difficult to clean for reuse. However, this drawback of the wall gap  525  is mitigated in single-use applications. The wye-piece  500  is generally a single-use coaxial wye-piece connector with the wall gap  525 , such that cleaning the wall gap  525  is unnecessary. 
     The wall gap  525  may have a thickness defined in part by the distance between the outer surface and the inner surface of the patient end  515 . If the patient end  515  is configured to have a dual taper design that supports a  15  mm female connection and a  22  mm male connection, then the wall gap  525  may have a thickness that is associated with the distance between the  15  mm female connection and the  22  mm male connection. Thus, the patient end  515  having a dual taper design does not exclude the possibility of having the wall gap  525 . 
     If the patient end  515  is has a solid wall, then more material (such as plastic) would be used in comparison to having the wall gap  525  in the patient end  515 , which reduces the material used by the volume of the cylindrical shell defined by the thickness of the wall gap  525 . Thus, the wall gap  525  may reduce the amount of material needed to manufacture the coaxial wye-piece  500  as well as reduce the manufacturing time of the coaxial wye-piece  500  since the thinner walls of the patient end  515  would take less time to cool. Otherwise, the wye-piece  500  maintains many of the features described of the wye-piece  400  shown in  FIG. 4 . The wye-piece  500  has a similar inspiratory branch and expiratory branch with tapers at the end of both. The patient end  515  of the wye-piece  500  may preserve the dual taper design such that the patient end  515  may act as either a male connector or a female connector. Note that wall gap  525  is a feature that may be present in combination with any of the embodiments of connectors disclosed herein including the embodiment of wye-piece  200  shown in  FIG. 2 . As further examples, it may also be applied in combination with the embodiments shown in  FIGS. 4, 6, 7A, 7B, 9, 10, 11, and 12 . 
     Wye-Piece Geometry (FIGS.  6 ,  7 A,  7 B,  8 A,  8 B, and  9 ) 
       FIG. 6  is a cutaway view illustrating the geometry and positioning of features for a connector in the respiratory assistance system  100  that includes a coaxial wye-piece  600 . 
     The coaxial wye-piece  600  may be the same embodiment as the coaxial wye-piece  400  shown in  FIG. 4 . The wye-piece  600  may be opaque or it may be transparent to some degree in order to show the internal construction of the wye-piece  600 . In some embodiments, the wye-piece  600  may have a certain colour and/or degree of transparency to indicate whether it is a single-use wye-piece or a reusable wye-piece. The coaxial wye-piece  600  has some similar features to the coaxial wye-piece  400 , including an inspiratory branch  605 , an expiratory branch  610 , a patient end  615 , and a lip  620 . However, there may be minor changes with regards to the spacing, angle, or length of the ports and branches. 
     A length  630  is the length between the tapered end of the inspiratory branch  605  and the intersection of the main body of the wye-piece  600 . Over the length  630 , the inspiratory branch  605  narrows. This configuration speeds up the flow of respiratory gas moving towards the patient end  615 . However, in some embodiments, the inspiratory branch  605  does not narrow. In various embodiments, the length  630  may be altered to serve specific design goals. In various embodiments, the length  630  may be increased in order to provide more space for connectors. 
     An angle  640  is the angle between the inspiratory branch  605  and the expiratory branch  610 . In various embodiments, the angle  640  may be in the range of between 0 and 180 degrees. In various embodiments, the angle  640  may be in the range of between 0 and 90 degrees. For practical reasons, the angle  640  is normally within the range of 0 and  90  degrees, such that gas flowing into the inspiratory branch  605  is naturally directed towards the patient end  615 . In some embodiments, the angle  640  is between 30 and 60 degrees. In some embodiments, the angle  640  is between 40 and  50  degrees. In some embodiments, the angle  640  is  45  degrees. 
     A length  635  is the length between the dual-tapered patient end  615  and the expiratory branch  610 . In various embodiments, the length  635  may be altered to serve specific design purposes. In various embodiments, the length  635  is at least the distance from the lip-end of the inspiratory branch  605  to the patient end  615 . In various embodiments, including the one shown in  FIG. 6 , the length  635  is significantly greater (by a factor of two in the illustration) than the distance from the lip-end of the inspiratory branch  605  to the patient end  615 , in order to accommodate at least any taper at the end of the expiratory branch  610 . This allows the expiratory branch  610  to be connected to other objects in the respiratory assistance system  100 , such as the expiratory conduit  117 . In some embodiments, the length  635  may be altered in order to accommodate or fit an MDI port or other feature, such as a pressure port. Further discussion on MDI port placement is provided below in reference to  FIG. 7A . 
     A dotted line  645  shows how the tip or end of the inspiratory branch  605  near the lip  620  may be trimmed. In various embodiments, the tip of the inspiratory branch  605  may be trimmed in order to reduce resistance to flow from the patient end  615  toward the expiratory branch  610 , as well as material usage and cost, in comparison to having an extended tip. The shortened tip can still prevent condensate from entering the inspiratory branch  605  since the lip  620  will still be present. The shortened tip will also still direct respiratory gas flow towards the patient end  615 . A minimum amount of tip is desirable in order to direct a flow of gases to the patient  101 . 
     There is an inner diameter change  625  in the inner surface of the body of the wye-piece  600  between the expiratory branch  610  and the patient end  615 . In some embodiments, the inner diameter change  625  is not present. The inner diameter change  625  accommodates a smaller inner surface diameter at the patient end  615  due to the taper needed for the patient end  615  to serve as a  15  mm female connector. In some embodiments, the dual taper of the patient end  615  does not conform to the standard  15  mm female connection. The patient end  615  may have a taper for any size female connection, such as  13  mm,  17  mm,  19  mm, and so forth. The inner diameter change  625  may be different to accommodate the taper or the inner surface diameter of the patient end  615 . The inner diameter change  625  may be a smooth inner transition in diameter from the expiratory branch  610  and the patient end  615 . A stepwise, or other similarly abrupt, change in diameter may affect the cleaning and flow characteristics of the wye-piece  600 . The wye-piece  600 , with the inner diameter change  625  having a smooth transition, has a resistance to flow that is very similar to a wye-piece with no inner diameter change. 
     To the implement inner diameter change  625 , an upper wall  650  of the wye-piece  600  that is near the lip  620  can be straight rather than angled in order to aid in manufacturing. In some embodiments, the upper wall  650  will be straight. In other embodiments, the upper wall  650  will be angled to contribute to the inner diameter change  625 . If the upper wall  650  is straight, then the inner diameter change  625  may not be attributed to a change in the upper wall  650 , but rather a change in the wall thickness of the wall on the opposite side of the upper wall  650 . This can be seen in  FIG. 6  in the lower wall directly below the inner diameter change  625 . 
     Changing the diameter of the inspiratory conduit  103 , which may be a smooth-bore conduit, may also be reflected in a change in the diameter of the inspiratory branch  605  and may affect the function and design of the wye-piece  600 . For instance, a decrease in the diameter of the smooth-bore conduit may be reflected in the inspiratory branch  605  in a variety of ways. For example, there may be an aggressive taper at the end of the inspiratory branch  605  in order to fit the decreased smooth-bore conduitdiameter. The respiratory gases flowing through the smooth-bore conduitwill slow down once it enters the inspiratory branch  605 . The respiratory gases flow may speed up again as the diameter of the inspiratory branch  605  narrows. As another example, the inner diameter of the inspiratory branch  605  may be decreased in order to match the decreased smooth-bore conduitdiameter. This may be accomplished by reducing the outer diameter of the inspiratory branch  605  and/or by increasing the thickness of the walls of the inspiratory branch  605 . The result will be faster respiratory gas flow through the smooth-bore conduit and the inspiratory branch  605  due to the decreased diameter. 
     Thus, the length  630 , the length  635 , the angle  640 , the length of the tip of inspiratory branch  605 , the diameter of inspiratory branch  605 , and the inner diameter change  625  all may be changed independently or in consideration of one another in order to facilitate a specific design purpose. For example, if directing respiratory gas flow from the inspiratory branch  605  towards the patient end  615  is a priority, then the angle  640  may be chosen to be smaller, and the tip of the inspiratory branch  605  may be chosen to be longer. All of these changeable features described here in connection to  FIG. 6  may be applied to any other embodiment of a coaxial wye-piece described herein, including but not limited to, the embodiments shown in  FIGS. 4, 5A, 5B, 9-12 . 
       FIG. 7A  illustrates an embodiment where an MDI port may be located on a coaxial wye-piece connector in the respiratory assistance system  100 . The coaxial wye-piece connector shown has an inspiratory branch  705 , an expiratory branch  710 , and a patient end  715 . In some cases, it may be desirable for the coaxial wye-piece connector to have an MDI port. However, such an MDI port should generally not be located on the tapers towards the ends of inspiratory branch  705 , expiratory branch  710 , and patient end  715 . Locating an MDI port on a taper would impair the taper and interfere with the ability of that end of the wye-piece to serve as a connector. The MDI port should also be associated with inspiratory gases, such that any medication delivered through the MDI port is delivered to the patient during inspiration. Thus, the MDI port may be positioned anywhere on the inspiratory branch  705  of the wye-piece that does not form the taper of the inspiratory branch  705 . This permissible area of placement is shown in  FIG. 7A  as section  730  of the inspiratory branch  705 . 
       FIG. 7B  is a diagram illustrating a connector for a respiratory assistance according to an example embodiment in which the connector comprises a coaxial wye-piece with an MDI port  735 . The figure is similar to  FIG. 7A , with the connector having the same inspiratory branch  705 , an expiratory branch  710 , and a patient end  715 . Inspiratory branch  705  has an MDI port  735  located in section  730  of the inspiratory branch  705 . Note that MDI port  735  may actually be located anywhere within section  730 . 
       FIGS. 8A and 8B  are cross-sectional views that further show the geometry and dimensions for a connector in the respiratory assistance system  100  that comprises a coaxial wye-piece. 
     In  FIG. 8A , representations of the lengths and distances of various features are shown. 
     A length  805  represents the distance between where the inspiratory branch begins to narrow and where the inspiratory branch connects to the body of the wye-piece. The length  805  may be measured along the axis of the inspiratory branch. Changing the length  805  may alter the rate at which the inspiratory gas flow speed changes as the inspiratory branch narrows. 
     For the portion of wye-piece between the patient end and the expiratory branch, a length  810  represents the horizontal distance between where the inspiratory branch joins the wye-piece to the inner diameter change. Changing the length  810  may alter the resistance to flow of the wye-piece. 
     A length  815  represents the distance between where the inspiratory branch connects to the body of the wye-piece to the tip of the inspiratory branch. The length  815  may be measured along the axis of the inspiratory branch. Changing the length  815  may alter the resistance to flow of the wye-piece. The length  815  may be shortened such that the tip of the inspiratory branch still has a lip, allowing for condensate to still be obstructed from entering the inspiratory branch. One side of the inspiratory branch may be shortened so that the tip of the inspiratory branch still has a lip, as shown in  FIG. 6  in which the inspiratory branch may be shortened up to the dotted-line  645 . 
     A length  820  represents the distance from the upper wall to the lip of the tip of the inspiratory branch. The length  820  may be measured along the outer surface of the tip of the inspiratory branch. Changing the length  820  may alter the size of the lip. 
     A length  825  represents the inner surface diameter of the tip of the inspiratory branch. The length  825  may be changed to affect the inspiratory gas flow speed being delivered towards the patient end. A smaller diameter will result in higher flow speed, and increased resistance to flow, while a larger diameter will result in lower flow speed, and decreased resistance to flow. 
     The table below provides approximate dimensions of the lengths illustrated in  FIG. 8A . 
     
       
         
           
               
            
               
                   
               
               
                 Dimensions of FIG. 8A 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 Illustrated Dimension 
                 Alternative Dimensions 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Length 805 
                 13 
                 mm 
                 10-25 
                 mm 
               
               
                 Length 810 
                 31 
                 mm 
                 20-40 
                 mm 
               
               
                 Length 815 
                 16 
                 mm 
                 5-20 
                 mm 
               
               
                 Length 820 
                 8 
                 mm 
                 4-10 
                 mm 
               
               
                 Length 825 
                 10 
                 mm 
                 5-15 
                 mm 
               
               
                   
               
            
           
         
       
     
     In  FIG. 8B , representations of the angles of various features are shown. 
     An angle  830  is the angle between the axis of the inspiratory branch and the axis of the expiratory branch. Changing the angle  830  may alter how the inspiratory gas flowing through inspiratory branch is directed towards the patient end. At higher values for the angle  830 , the inspiratory gas becomes less directed towards the patient end and increasingly directed towards the opposing wall facing the tip of the inspiratory branch. 
     An angle  835  is the angle between the narrowing portion of the inspiratory branch and the axis of the inspiratory branch. Changing the angle  835  may alter the rate of change of the narrowing of the inspiratory branch. At higher values for the angle  835 , the inspiratory branch may narrow quickly. This may result in the flow speed of inspiratory gases increasing more rapidly over the narrowing portion as opposed to lower values for the angle  835 . 
     An angle  840  is the angle between the tip of the inspiratory branch and the axis of the expiratory branch. Changing the angle  840  may alter the resistance to flow of the wye-piece as well as how inspiratory gas is directed towards the patient end. For greater values of the angle  840 , there may be greater resistance to flow. However, inspiratory gas is better directed towards the patient end. For lower values of the angle  840 , there may be less resistance to flow but inspiratory gas is not as well directed towards the patient end. The angle  840  may be chosen in order to achieve the desired features of the wye-piece and strike the right balance between resistance to flow and directing gas towards the patient end. 
     The table below provides approximate dimensions of the angles illustrated in  FIG. 8B . 
     
       
         
           
               
            
               
                   
               
               
                 Angles of FIG. 8B 
               
            
           
           
               
               
               
            
               
                   
                 Illustrated Dimension 
                 Alternative Dimensions 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Angle 830 
                 50° 
                 50-90° 
               
               
                   
                 Angle 835 
                 12° 
                 10-90° 
               
               
                   
                 Angle 840 
                 20° 
                  0-35° 
               
               
                   
                   
               
            
           
         
       
     
     Thus, the dimensions of the various lengths described in reference to  FIG. 8A , the dimensions of the various angles described in reference to  FIG. 8B , and the dimensions of the various features described in reference to  FIG. 6  (which include the length  630 , the length  635 , the angle  640 , the length of the tip of the inspiratory branch  605 , the diameter of the inspiratory branch  605 , and the inner diameter change  625 ) may all be chosen in order to facilitate the desired functionality of the wye-piece. The desired wye-piece connector may be designed to have at least one of a specific resistance to flow (especially with regards to the expiratory branch), inhibit condensate movement into the inspiratory branch to a certain degree, minimize carbon dioxide build-up, have an MDI port for the patient&#39;s convenience, and/or meet a certain degree of usability (such as by eliminating the need for a user to set up the wye-piece in a specific orientation). 
       FIG. 9  illustrates a connector for the respiratory assistance system  100  according to another example embodiment, where the connector comprises a coaxial wye-piece  900 . 
     The coaxial wye-piece  900  has an inspiratory branch  905 , an expiratory branch  910 , and a patient end  915 . An angle  930  between the inspiratory branch  905  and the expiratory branch  910  is greater than the angles in some of the other embodiments shown in the figures, such as the embodiment shown in  FIG. 4 . The larger angle  930  makes inspiratory gas from the inspiratory branch  905  less directed towards the patient end  915  of the wye-piece  900 . For example, the inspiratory gas retains a significant horizontal momentum that may carry it into the wall of the wye-piece  900  directly opposing the tip of the inspiratory branch  905  (not shown). 
     The inspiratory branch  905  shown is also shorter in length than the inspiratory branch of the embodiment in  FIG. 4 . The taper on the end of the inspiratory branch  905  takes up most of the length of the inspiratory branch  905 . The length of the narrowing portion of the inspiratory branch  905  is very short. 
     Coaxial Wye-Piece With Inner Coaxial Tube (FIGS.  10 ,  11 , and  12 ) 
       FIG. 10  illustrates a connector for the respiratory assistance system  100  according to an example embodiment, where the connector includes a coaxial wye-piece  1000 . 
     Coaxial wye-piece  1000  has an inspiratory branch  1005 , an expiratory branch  1010 , and a patient end  1015 . There is also an inner coaxial inspiratory tube  1050  which runs the length of the patient end  1015  of the wye-piece  1000 . Inner coaxial inspiratory tube  1050  is an extension of inspiratory branch  1005  that extends from the inspiratory branch  1005  into the wye-piece  1000 . Inner coaxial inspiratory tube  1050  helps to ensure that condensate is directed away from the inspiratory gas flow because inner coaxial inspiratory tube  1050  is pointed towards patient interface  115 . The interface connector of patient interface  115  does not contact the inner coaxial inspiratory tube  1050 . The interface connector would connect to patient end  1015  so that inspiratory and expiratory gas may pass through the interface connector. 
     However, the inner coaxial inspiratory tube  1050  may have a negative impact on resistance to flow as there may only be a small amount of available space within the  15  mm taper of the patient end  1015  to fit a completely coaxial tube. The presence of the inner coaxial inspiratory tube  1050  may also restrict the expiratory flow towards the expiratory branch since it takes up a significant portion of the cross-section of the wye-piece  1000 . 
       FIG. 11  illustrates a connector for the respiratory assistance system  100  according to an example embodiment, where the connector comprises a coaxial wye-piece  1100 . 
     The coaxial wye-piece  1100  has an internal coaxial tube  1150  that terminates before the connection point with the interface at the patient end. The internal coaxial tube  1150  has a relatively short lip. The internal coaxial tube  1150  takes up a significant portion of the cross section of the flow path towards the expiratory branch, which may be a factor in condensate entering the inspiratory branch under certain conditions. 
       FIG. 12  illustrates a connector for the respiratory assistance system  100  according to an eighth example embodiment, where the connector comprises a coaxial wye-piece  1200 . 
     The coaxial wye-piece  1200  has an internal coaxial tube  1250  that also terminates before the connection point with the interface at the patient end. The internal coaxial tube  1250  has a relatively longer lip than the lip of the internal coaxial tube  1150  shown in  FIG. 11 . Like in  FIG. 11 , here the internal coaxial tube  1250  takes up a significant portion of the cross section of the flow path towards the expiratory branch, which may be a factor in condensate entering the inspiratory branch under certain conditions. 
     Additional Description 
     It should be understood that any examples used in this description are in no way limiting, but merely illustrative of possible embodiments for purposes of clarification. Unless the context clearly requires otherwise, throughout this description and the claims that follow, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”. 
     Reference to any prior art in this description is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art referenced forms part of the common general knowledge in any relevant field of endeavour in any country in the world. 
     The present invention may be said broadly to consist in the parts, elements, and features referred to or indicated in this description and the claims that follow, individually or collectively, in any or all combinations of two or more of said parts, elements, or features. Where reference is made to integers or components having known equivalents thereof, those equivalents are herein incorporated as if individually set forth. 
     It should be noted that various modifications to the embodiments disclosed herein will be apparent to those skilled in the art. Such modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. For instance, various components may be repositioned or reshaped as desired. It is therefore intended that such modifications be included within the scope of the invention. Moreover, not all of the features, aspects, and advantages disclosed herein are necessarily required to practice the present invention. Accordingly, the scope of the present invention is intended to be defined only by the claims that follow.