Patent Publication Number: US-2007122784-A1

Title: Test lung devices

Description:
CROSS-REFERENCES TO OTHER RELATED PATENT APPLICATIONS  
      This application claims the benefit of U.S. Provisional Application Ser No. 60/680,737 filed May and 13, 2005 and U.S. Provisional Application Ser. No. ______ filed May 15, 2006 which are incorporated herein by reference in their entireties. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not Applicable.  
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX  
      Not Applicable.  
     BACKGROUND  
      Embodiments of the claimed subject matter relate generally to lung simulators which are used with ventilators for training, testing and troubleshooting. More particularly, the embodiments relate to devices and methods used to simulate human or other animal lungs and to test how lung simulators can be coupled to a ventilator. Test lung devices simulate certain aspects of human or animal lungs which allow for training of medical technicians as well as the testing and troubleshooting of ventilators without having to use human or animal subjects.  
     SUMMARY  
      One aspect of the present teachings relates to a test lung device that includes a plurality of air chambers. Each chamber includes an inflatable bag, and the plurality of inflatable bags of the plurality of air chambers are coupled to an air interface that connects to an external device. Each chamber further includes first and second interconnected panel portions positioned so that the inflatable bag is interposed therebetween. The interconnected panel portions flex as the bag is inflated, and the flexing panel portions provide a restoring force that deflates the bag_ Such panel portions corresponding to the plurality of air chambers are interconnected by connecting panel portions that provide mechanical coupling between the plurality of air chambers.  
      Another aspect of the present teachings relates to an air chamber of a test lung device. The air chamber includes an inflatable bag that has a deformable and restorable insert therein. The insert inhibits the inflatable bag from collapsing when in a relaxed configuration. The bag can be collapsed by squeezing the bag. The restorative property of the insert restores the bag to its non-collapsed relaxed configuration when the squeezing force is removed. As the bag is restored to its relaxed configuration, a negative pressure situation is created temporarily in the air chamber.  
      Yet another aspect of the present teachings relates to a flow adapter for coupling a test lung device to a ventilator. The flow adapter includes a plurality of tubular members having first and second ends. Each tubular member defines first and second spaces adjacent the first and second ends. Each tubular member further defines a partition that is positioned between the first and second spaces. The partition defines an aperture that allows air to flow between the first and second spaces. The first and second spaces of the plurality of tubular members are dimension to receive air interface portions of the test lung device and the ventilator. The apertures of the plurality of tubular members can be dimensioned differently so as to provide different flow rates for different tubular members.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows one embodiment of a test lung assembly coupled to ventilator hoses via one embodiment of a flow adapter having a plurality of conduits having different flow characteristics;  
       FIG. 2  shows a partially unassembled view of  FIG. 1 ;  
       FIG. 3  shows the test lung and the flow adapter in a coupled configuration;  
       FIG. 4  shows a close-up of an uncoupled configuration of the test lung and the flow adapter;  
       FIG. 5  shows an isolated view of one embodiment of the flow adapter, showing that different flow characteristics of the plurality of conduits can be achieved by different sized restricting apertures;  
       FIG. 6  shows an isolated view of one embodiment of a coupler that couples ventilator hoses to one of the conduits of the flow adapter;  
       FIG. 7  shows an isolated view of one embodiment of a test lung having two or more air chambers;  
       FIG. 8  shows a partially unassembled view of the test lung of  FIG. 7 , showing that the air chambers include separate expandable bags that are Y-coupled to allow coupling to one of the conduits of the flow adapter;  
       FIG. 9  shows an isolated breakaway view of one embodiment of a flexible panel that can be shaped to accommodate the expandable bags as they expand and contract;  
       FIG. 10  shows an isolated view of one embodiment of the expandable bag; and  
       FIGS. 11A and 11B  show cross-sectional views of one embodiment of an expandable bag having an insert that allows generation of a negative pressure in the bag;  
       FIG. 12  illustrates a top view of another embodiment of the air interface;  
       FIG. 13  illustrates a side view of the embodiment of  FIG. 12 ;  
       FIG. 14  is a front side perspective view of an embodiment of the air interface.  
       FIG. 15A  is a top perspective view of an embodiment of the annulate accommodating air interface with the annulate removed.  
       FIG. 15B  is a top perspective view of an embodiment of the annulate. 
    
    
      These and other aspects, advantages, and novel features of the present teachings will become apparent upon reading the following detailed description and upon reference to the accompanying drawings. In the drawings, similar elements have similar reference numerals.  
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
      With reference now to the various figures in which identical elements are numbered identically throughout, a description of various exemplary aspects of the claimed subject matter will now be provided.  
      The present teachings relate to a test lung assembly, and also how any test lungs can be coupled to a ventilator. As is known, test lung devices simulate certain aspects of human lungs, thereby allowing testing of ventilators without having to rely on human subjects. For the purpose of description herein, “air” can refer to any gas compound or mixture that can be used with ventilators.  
       FIG. 1  shows one embodiment of an assembly  100  having a test lung  102  coupled to ventilator hoses  106  via a flow adapter  104 . The test lung  102  and the flow adapter  104  are described below in greater detail.  
       FIG. 2  shows the assembly of  FIG. 1  in a partially unassembled configuration. As shown, the test lung  102  includes a test lung air interface  110 . As also shown, the ventilator hoses  106  can be Y-coupled by a coupler having a ventilator air interface  112 .  
      As further shown in  FIG. 2 , the flow adapter  104  includes a plurality of tubular members  114   a ,  114   b ,  114   c  that extend in a generally parallel manner, so as to define a first end  116  and a second end  118 . In one embodiment as shown in  FIG. 2 , the flow adapter  104  includes three tubular members coupled to each other in a substantially fixed manner so as to form a closely-packed type configuration. In other embodiments, the tubular members are not necessarily attached to each other in a fixed manner. Also, other embodiments may have more than three, or less than three tubular members. Also, other embodiments may have the tubular members arranged in a non-closepacked configuration.  
      Each of the example tubular members  114   a ,  114   b ,  114   c  defines a first space adjacent the first end  116 , and a second space adjacent the second end  118 . In one embodiment, each of the tubular members  114   a ,  114   b ,  114   c  can have a cross-sectional shape that is substantially circular, such that the first and second spaces have a generally cylindrical shape. In one embodiment, the first and second spaces can be dimensioned to receive the test lung air interface  110  and the ventilator air interface  112 , respectively.  
      Additionally, the diameters of the test lung air interface  110  can be selected to be approximately same as that of the ventilator air interface  112 , and the first and second spaces can be dimensioned accordingly, so that the first end  116  can be interchanged with the second end  118 .  
       FIG. 3  shows a view of the flow adapter  104  coupled to the test lung  102  via the air interface  110 . As described herein, such a coupling allows air to flow in and out of the test lung  102  in a generally regulated manner. Furthermore, as also described herein, the test lung  102  having a plurality of air chambers provides flexibility in the manner in which the test lung  102  can be utilized in testing a given respirator.  
       FIG. 4  shows a closer unassembled view of the coupling between the test lung  102  and the flow adapter  104 . In one embodiment, as described above, the test lung air interface  110  can be dimensioned to fit into one of the plurality of spaces defined adjacent the first end  116  (or the second end  118  in the interchangeable-end embodiment). Thus, the test lung interface  110  inserted in a first space  120   a  adjacent the first end  116  is air-coupled to a second space  126   a  adjacent the second end  118 ; and a ventilator air interface (not shown) inserted into the second space  126   a  would then be air-coupled to the test lung  102 . Similar air-coupling can be achieved using the combinations of spaces  120   b / 126   b  and  120   c / 126   c  ( 126   c  hidden from view).  
      The foregoing arrangement can provide for different flow rates between the test lung  102  and the ventilator at the flow adapter  104 .  FIG. 5  shows one example of how such different flow rates can be achieved. In one embodiment as shown in  FIG. 5 , each of the tubular members  114   a ,  114   b ,  114   c  define first and second spaces  120 ,  126  (second spaces  126  not shown in  FIG. 5 ). In one embodiment, each of the tubular members  114   a ,  114   b ,  114   c  includes a partition  122  interposed between the first and second spaces  120 ,  126 . Each partition  122  defines an aperture  124  that allows flow of air between the first and second spaces  120 ,  126 . The apertures  124  can be dimensioned differently to allow different flow rate of air.  
      In an embodiment shown in  FIG. 5 , the first partition  122   a  defines the first aperture  124   a  having a first dimension. The second partition  122   b  defines the second aperture  124   b  having a second dimension that is larger than the first dimension, thereby allowing a greater air flow than the first aperture  124   a . Similarly, the third partition  122   c  defines the third aperture  124   c  having a third dimension that is larger than the second dimension, thereby allowing a greater air flow than the second aperture  124   b.    
      In one embodiment, the partitions  122  can be positioned at an approximately midpoint between the first and second ends  116 ,  118 , such that the first and second spaces  120 ,  126  are substantially similar for a given tubular member  114 . For such an embodiment, either of the first and second spaces  120 ,  126  can receive either of the air interfaces ( 110  for the test lung, and  112  for the ventilator).  
       FIG. 6  shows one embodiment of a coupler  130  having the air interface ( 112  or  110 ) that is dimensioned to fit into the foregoing first or second space  120 ,  126 . The air interface ( 112  or  110 ) is shown to be split into a first conduit  132  and a second conduit  134  so as to form a “Y” shaped coupling. Such a coupling allows the air interface ( 112  or  110 ) to be coupled to two air conduits (such as two ventilator hoses or two air chambers.) Of course, if there are more than two conduits, then the air interface can be split into more-than two conduits. Not shown is an additional embodiment that includes one or more resistors disposed within one or more conduits  132  or  134  so as to provide increased resistance to one or both of the air flows. In use, one or more resistors may be used to simulate the resistive load of one or more particular air chambers at a time or one portion of the air chamber or air flow at a time. This allows the testing of air flow in a variety of different configurations for testing, training or troubleshooting a variety of real world conditions.  
      In one embodiment, the coupler  130  can provide a similar “Y”-coupling functionality on both the test lung side and the ventilator side. In one embodiment, substantially similar couplers  130  couple both the test lung and the ventilator to the flow adapter  104 . In another embodiment, the test lung side coupler  130  has a different dimension than the ventilator side coupler  130 .  
       FIG. 7  shows an isolated view of the example test lung  102  having a first air chamber  152  and a second air chamber  154 . In one embodiment as described below in greater detail, the first and second air chambers  152 ,  154  are coupled to the flow adapter  104  via a “Y” shaped coupler.  
      In one embodiment, the first air chamber  152  includes a first expandable bag  156 , and the second air chamber  154  includes a second expandable bag  158 . The first and second expandable bags  156 ,  158  are interposed between a first panel member  140  and a second panel member  142 . In one embodiment, the first and second panel members  140 ,  142  are interconnected at locations  148  (on the first air chamber side),  150  (on the second air chamber side), and  144 ,  146  (between the first and second air chambers). Thus, the first and second panel members  140 ,  142  partially constrain the bags  156 ,  158  as the bags expand and contract due to the operation of the ventilator.  
      In one embodiment, each of the first and second panel members  140 ,  142  defines a first panel portion  160  and a second panel portion  162 . The first and second panel portions  160 ,  162  can be interconnected by a connecting panel portion  164 . One can see that the interconnecting panel portion  164  can be dimensioned differently to provide different mechanical interconnecting property between the first and second panel portions  160 ,  162 . For example, a larger area of the interconnecting panel portion  164  can increase the mechanical coupling between the first and second panel portions  160  and  162 . Conversely, a smaller area of the interconnecting panel portion  164  can decrease the mechanical coupling between the first and second panel portions  160 ,  162 . Based on the foregoing mechanical coupling of the first and second panel portions  160 ,  162 , one can see that the constraining property of the first and second panel members  140 ,  142  (as the bags expand and contract) can be selected to provide a desired configuration. In other embodiments additional walls may be used to provide increased resistance in the inflation of the bags or decreased compliance of the lung load such as in a simulated situation of the breakdown of lung capacity.  
      As shown in  FIG. 7 , the first and second panel members  140 ,  142  can be interconnected to each other via a plurality of interconnections, such as those indicated as  144 ,  146 ,  148 ,  150 . With such example interconnections, the first and second panel members  140 ,  142  can maintain a substantially relaxed configuration when the bags  156 ,  158  are deflated. As the bags  156 ,  158  become inflated, the panel portions  160 ,  162  of the first and second panel members  140 ,  142  can bulge out. That is, the first panel portions  160  of the first and second panel members  140 ,  142  bulge away from each other at locations between the interconnections  148  and  144 . Similarly, the second panel portions  162  of the first and second panel members  140 ,  142  bulge away from each other at locations between the interconnections  150  and  146 .  
      In one embodiment, the first and second panel members  140 ,  142  are formed from a flexible panel so as to facilitate the foregoing bulging. When bulged, the panel portions  160 ,  162 , in conjunction with the interconnections  144 ,  146 ,  148 ,  150 , can provide a restorative force so as to induce deflation of the bags  156 ,  158 , thereby simulating the function of a lung. In one embodiment, the first and second panel members  140 ,  142  are configured so as to provide the deflating restorative force when the bags  156 ,  158  are substantially far within their elastic limit. Because the bags do not need to stretch much to provide the “exhale” portion, one can see that the useful “lifetime” of the bags can be improved.  
      As described above, the first and second panel portions  160 ,  162  can mechanically coupled by the interconnecting panel portion  164 . As the test lung operates (expansion-relaxation cycles), the mechanically-coupled air chambers  152 ,  154  can provide a significantly greater ranges and types of mechanical responses than a single-chamber devices or devices where the air chambers are substantially independent.  
       FIG. 8  shows a partially unassembled view of the example test lung of  FIG. 7 , showing by example how the bags  156 ,  158  can be installed and coupled to the air interface  110 .  FIG. 8  also shows how the example interconnections  144 ,  146 ,  148 ,  150  can be configured to allow a quick assembly of the first and second panel members  140 ,  142 .  
      In one embodiment of the first panel member  140  as shown in  FIG. 8 , the example interconnection  144  defines a recess  174  that is dimensioned to receive a protrusion similar to a protrusion  176  of the interconnection  146 . Similarly, the example interconnection  148  defines a recess  178  that is dimensioned to receive a protrusion similar to a protrusion  180  of the interconnection  150 . In one embodiment, the second panel member  142  (not shown) can be substantially similar to the first panel member  140 , such that when being assembled facing each other, the recess  174  of the first panel member  140  receives the protrusion  176  of the second panel member  142 , and so on. In one embodiment, such matching recesses and protrusions are dimensions so as to allow snap-fitting, such that the first and second panel members  140 ,  142  can be assembly by simply snapping the matching interconnections together.  
      In one embodiment as shown in  FIG. 8 , the bags  156 ,  158  include loops  200  and  202  which are positioned generally opposite from their mouths  196 ,  198 . The first and second panel members  140 ,  142  can be dimensioned to generally accommodate the bags  156 ,  158 , and the interconnections  148 ,  150  can be positioned so as to allow retaining of the loops  200 ,  202 . The mouth ends  196 ,  198  are shown to receive first and second conduits  192 ,  194  of one embodiment of a Y-coupler  190 , such that the first and second bags  156 ,  158  can be air-coupled to the air interface  110 . In addition to providing the air-coupling, the Y-coupler  190  can be retained by the first and second panel members  140 ,  142 , thereby retaining the bags  156 ,  158 .  
       FIG. 9  shows an isolated view of the example panel member  140 . In one embodiment, the panel member  140  includes a plurality of walls  214  about the air interface ( 110 , not shown) end. A portion of the walls  214  is shown to define a cutout  216  dimensioned to receive the air interface  110  portion of the Y-coupler  190 . Thus, when the first and second panel members  140 ,  142  are assembled, the Y-coupler  190  can be retained by the walls  214 .  
       FIG. 10  shows an isolated view of one embodiment of a bag  220  that can be used in the test lung described herein. In one embodiment, the bag  220  is substantially hollow inside. In another embodiment, the bag  220  includes an insert that provides a relaxed configuration where the bag  220  is not collapsed. While the hollow bag  220  can be in a non-collapsed configuration, it may not be consistent. For example, if the bag  220  is squeezed, it may not recover to the non-collapsed configuration. On the other hand, the insert can provide the non-collapsed relaxed configuration in a generally consistent manner. The non-collapsed configuration of the bag  220  can provide a negative pressure situation, where the action of the bag draws air inward. Such a feature can be useful in testing a triggering mechanism of a ventilator.  
       FIGS. 11A and 11B  show cross-sectional views of one embodiment of a bag  230  having an insert  232 . In  FIG. 11A , the bag  230  is shown to be in a squeezed configuration such that the overall inside air volume is reduced. Such squeezed configuration can be achieved by, for example, an operator squeezing (depicted as arrows  234 ) the panels ( 236 ) of the corresponding air chamber of the test lung.  
      In  FIG. 11B , the bag  230  is shown to substantially restore itself to its relaxed configuration due to the insert restoring itself when the squeezing force is removed. As the bag restores itself, the air volume is increased, thereby creating a temporary negative pressure situation. In one embodiment, the insert  232  can be formed from materials such a foam that has mechanical restorative properties. Other embodiments may use any other suitable material such as sponge, rubber or silicone. A latex free foam may be used in other embodiments.  
       FIG. 12  illustrates a top view of another embodiment of the air interface  110  having an annulet  250  employed to close or open an aperture  252 . The annulate  250  is slidably disposed over the surface of the air interface  100 . When turned by the user, it covers or uncovers one or more apertures  252 . When uncovered, aperture  252  allows air to flow out of the air interface  100  into the environment simulating an air leak.  
       FIG. 13  illustrates a side view of the embodiment of  FIG. 12  with the annulate  250  slidably engaged along the surface of the air interface  110 . In use, annulate  250  can be snapped into place and set to restrict air flow or allow air flow to leak into the environment. A no leak position for annulate  250  is indicated as numeral  258  in  FIG. 13 .  FIG. 14  is a front side perspective view of the air interface  110  and annulate  250  of  FIGS. 12 and 13 .  FIG. 14  also illustrates a lanyard tether  260  which can be used to secure the air interface  110 . Tether  260  can also be disposed on any other component of the embodiments of the claimed subject matter, for example the coupler  130  and/or the ventilator interface  112 .  FIG. 15A  is a top perspective view of the annulate showing the air interface  110  with aperture  256  exposed and annulate  250  removed. Aperture  256  can be aligned with one or more apertures found in the annulate  250  so that air can flow at varying rates from air interface  100  into the environment.  FIG. 15B  is a top perspective view of an embodiment of annulate  250  showing two apertures, aperture  252  and  254  having differing diameters so that the rate of air flow can be varied depending on the aperture selected by the user.  
      In another embodiment, one or more annulate  250  and one or more apertures  252  or  254  may be accommodated within and disposed on one or more of the tubular members  114 . The annulate  250  in other embodiments may be a partial annulate and the aperture  252  may be of any suitable diameter. A no leak position on an air intake  110  or a tubular member  114  may also be provided to indicate the position in which the annulate will cover the apertures  252  so no loss of air will occur.  
      Embodiments of the claimed subject matter can be used to simulate a large amount of varying quantities of breaths, for example from 25 mL to 2.5 Liters. They can also be used with varying ventilation and triggering modes. The size of embodiments can similarly vary according to the needs of the users. For example, embodiments can be used in neonatal sized, adult sizes or any other variation. Embodiments may also be easily transported in small cases. One embodiment has dimensions of 10.5×11.5×1.5 includes allowing it to fit in a standard sized suitcase.  
      Embodiments also include various modes such as volume and pressure control. Triggers include but are not limited to the flow trigger and the pressure trigger. In some embodiments the usable pressure can vary greatly, for example from 0 to 120 cmH 2 O. The sensitivity can also vary, for example from 0 to −20 cmH 2 O so that embodiments may be used with any commercially available ventilator.  
      Example resistances of the coupler  130  includes conduits with resistances of Rp5 cmH 2 O/l/s (for example used for Vt&gt;300 ml,) Rp20 cmH 2 O/l/s (for example in use for Vt 30-300 ml,) and Rp50 cmH 2 O/l/s (for example used for Vt&lt;30 ml.) Any other suitable resistance may be used with the one or more conduits  132  or  134  in the coupler  130 .  
      Although the above-disclosed embodiments have shown, described and pointed out the fundamental novel features of the claimed subject matter as applied to the above-disclosed embodiments, it should be understood that various omissions, substitutions, and changes in the form of the detail of the devices, systems and/or methods shown may be made by those skilled in the art without departing from the scope of the claimed subject matter. Consequently, the scope of the claimed subject matter should not be limited to the forgoing description.