Abstract:
An adapter couples a patient&#39;s breathing circuit to a ventilator. In the preferred embodiment, the adapter comprises an inhalation conduit having a first end for coupling the adapter to the ventilator and a second end for coupling the adapter to the patient breathing circuit; an exhalation conduit having a first end for coupling the adapter to the patient breathing circuit and a discharge conduit, the discharge conduit transversely oriented to the inhalation conduit; an exhaust port communicating with the discharge conduit for releasing breathed gas from same; a valve selectively opening and closing the discharge conduit to release gas from same; and a base comprising means for releasably coupling the adapter to the ventilator.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention is directed to an adapter for coupling a patient breathing circuit to a ventilator. In the preferred embodiment, the present invention relates to a breathing circuit adapter for interconnecting a patient&#39;s breathing circuit, a pressure monitor, a source of aerosolized medicine and a ventilator.  
         [0002]     Patients that have ventilatory difficulties are often placed on a ventilator. A ventilator is a mechanical device designed to provide all or part of the work a body must produce to move gas into and out of the lungs. The ventilator delivers breathable gas to a patient and carries breathed gas from the patient through a set of flexible tubes called a patient breathing circuit. Typically, the patient breathing circuit connects the ventilator to an endotracheal or tracheostomy tube that extends into the patient&#39;s throat or to a mask covering the patient&#39;s mouth and/or nose. Such a connection is often made via a Y-piece connector, which unites the inhalation and exhalation conduits and provides a means for permitting gas flow in either conduit based upon whether patient inhalation or exhalation is occurring. The endotracheal tube or tracheotomy tube may include a balloon cuff to provide a seal inside the trachea for the tracheal tubes or a mask may have a seal around the mouth and nose to sustain a predetermined air pressure within the circuit and patient lungs.  
         [0003]     Most ventilators have at least one pressure monitor that measures patient airway pressures to gauge the pressure of the breathing gas delivery and whether or not the patient is properly connected to the ventilator. Many ventilators have sophisticated pressure, volume and flow sensors that produce signals both to control the ventilator output and to provide displays of how the ventilator and patient are interacting.  
         [0004]     To medicate a patient on a ventilator, aerosolized medicine is often installed into the breathing circuit. A device for delivering aerosolized medicine, such as a nebulizer, introduces the aerosoled medication periodically as prescribed into the breathable gas flowing through the inspiratory conduit of the patient circuit and ultimately to the patient&#39;s airway and lungs. As with any dispensation of medication to a patient, it is desirable to provide a delivery device/ventilator/breathing circuit adapter that optimizes dosage control and maximizes deposition of aerosolized medicine in the inhaled gas.  
         [0005]     Typically, devices for delivering aerosolized medicine, such as nebulizers, have been coupled to the patient circuit proximate to the patient interface (i.e. the endotracheal or tracheostomy tube or mask) at the Y-piece connector. However, recent studies have concluded that in many instances coupling the nebulizing device to the patient circuit proximate to the ventilator provides better deposition of aerosolized medicine during the inhalation phase. During the exhalation phase the ventilator, or nebulizer, provides a small bias flow rate while the nebulizing device continuously atomizes medicine at a fixed rate. With the nebulizer placed proximate to the ventilator (at the distal end of the inspiratory circuit relative to the patient), the bias flow charges the inspiratory circuit with aerosol during the expiratory phase. In contrast, aerosol generated with the nebulizer positioned at the patient Y-piece is directed down the expiratory conduit of the patient circuit during the exhalation phase, reducing the amount of medicine available to the patient.  
         [0006]     For the foregoing reasons, an efficient means for coupling a patient breathing circuit to a ventilator is desirable. An efficient means for coupling a delivery device for aerosolized medicine to a patient breathing circuit proximate to a ventilator is also greatly desired. Specifically, it is desirable to provide a breathing circuit adapter for interconnecting a delivery device for aersolized medicine, such as a nebulizer, proximate to a ventilator and distal from the patient relative to the inspiratory circuit, thus maximizing efficiency and the amount of medicine provided to the patient. It is desirable to provide such a breathing circuit adapter which is simple, easy to use, and comprises minimal parts to therefore minimize chances for mechanical breakdown.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides an efficient means for coupling a patient breathing circuit to a ventilator. The present invention also provides an efficient means for coupling a delivery device for aerosolized medicine, such as a nebulizer, to a patient breathing circuit proximate to the ventilator.  
         [0008]     The adapter includes an inhalation conduit having a first end for coupling the adapter to the ventilator and a second end for coupling the adapter to the patient breathing circuit; an exhalation conduit having a first end for coupling the adapter to the patient breathing circuit and a discharge conduit, the discharge conduit transversely oriented to the inhalation conduit; an exhaust port communicating with the discharge conduit for releasing breathed gas from same; a valve selectively opening and closing the discharge conduit to release gas from same; and a base comprising means for releasably coupling the adapter to the ventilator.  
         [0009]     In the preferred embodiment, the adapter also includes a pressure sensing port for interconnecting a ventilator monitor with a monitoring port that is located in the breathing circuit proximate to the patient. A medicine delivery conduit communicates with the inhalation conduit intermediate its first and second ends and receives medicine and provides same to the inhalation conduit.  
         [0010]     The adapter is releasably mounted to the ventilator. Means for releasably mounting the adapter to the ventilator may include a camming mechanism that is manually actuated by the caregiver to uncouple the adapter from the ventilator.  
         [0011]     The adapter efficiently unites the necessary components for treating a patient on a ventilator with medicine. In one embodiment, the adapter is uniquely designed to couple the source of aerosolized medicine proximate to the ventilator and in a vertical orientation to provide better deposition of liquid aerosolized medicine during the inhalation phase of the patient&#39;s breathing cycle.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of the adapter of the present invention.  
         [0013]      FIG. 2  is a side view of the adapter.  
         [0014]      FIG. 3  is a sectional view of the adapter taken along section  3 - 3  shown in  FIG. 1 .  
         [0015]      FIG. 4  is a sectional view of the adapter taken along section  4 - 4  shown in  FIG. 3 .  
         [0016]      FIG. 5  is a sectional view of the adapter taken along section  5 - 5  shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     In the preferred embodiment of the present invention described in detail below, an adapter for a ventilation system employing a source of aerosolized medicine interconnects a patient&#39;s breathing circuit, a pressure monitor, a source of aerosolized medicine and a ventilator. It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention, which is more particularly defined in the appended claims. For example, although an adapter having coaxial breathing conduits is shown, it is contemplated that an adapter having non-coaxial or separate conduits is contemplated. In addition, although the adapter shown employs a source of aerosolized medicine, it is understood that an adapter without means for coupling to a source of aerosolized medicine is conceived.  
         [0018]     As shown in  FIG. 1 , the adapter  20  of the present invention is mounted to a ventilator  22 . The adapter  20  is designed to facilitate coupling of a source of aerosolized medicine, namely a nebulizer  24  (illustratively shown in  FIGS. 2 and 5 ) to a patient breathing circuit  26  proximate to the ventilator  22 . As described above, placement of the nebulizer  24  proximate to the ventilator  22  provides improved deposition of aerosolized medicine during a patient inhalation phase. Although in the preferred embodiment shown, the nebulizer  24  provides a source of aerosolized medicine to the breathed gas, it is contemplated that the adapter may be designed to function either with or without a variety of known delivery devices for aerosolized medicine.  
         [0019]     The adapter  20  is further designed to couple the nebulizer  24  in a vertical orientation, as shown. The vertical orientation is preferred for the nebulizer  24  to efficiently facilitate dispensation of liquid aerosolized medication to the patient, as is well known in the art.  
         [0020]     As shown in  FIGS. 1-3 , the adapter  20  of the present invention includes several components. The adapter  20  includes coaxial breathing conduits  28  including a central inhalation conduit  30  and surrounding exhalation conduit  32 . The coaxial breathing conduits  28  in the particular embodiment shown are tubular and designed to facilitate gas flow from the ventilator  22  to the patient breathing circuit  26 , and then back from the patient breathing circuit  26  to an exhaust port  34 , as shown in  FIG. 3  by arrows  35  and  37 . It should be recognized that the coaxial breathing conduits  28  may comprise a variety of shapes and sizes and are not limited by the particular shape depicted in the drawings.  
         [0021]     Referring to  FIG. 3 , the central inhalation conduit  30  has a first end portion  36  for coupling the adapter  20  to the patient breathing circuit  26 , an outwardly tapered portion  38 , and a second end portion  40  for coupling the adapter to the ventilator  22 . As will be explained further below, when the adapter  20  interconnects the ventilator  22  and the patient breathing circuit  24 , breathable gas flows from the ventilator  22 , through the central inhalation conduit  30 , to the inhalation tube  42  of the patient breathing circuit  26 , as shown by arrows  35 .  
         [0022]     Referring briefly to  FIG. 5 , the adapter  20  further includes a medicine delivery or nebulizer conduit  44  designed to facilitate flow of aerosolized medicine from the nebulizer  24  to the central inhalation conduit  30 . The nebulizer conduit  44  extends orthogonally from the coaxial breathing conduits  28  and has a first end  46  for coupling to the nebulizer  24  and a second tapered end  48  connecting to the central inhalation conduit  30 . As will be described further below, when breathable gas is flowing through the central inhalation conduit  30 , the nebulizer  24  deposits aerosolized medicine to the nebulizer conduit  44  and into the breathable gas stream. The vertical orientation of the nebulizer  24  advantageously enhances the efficiency of dispensation of aerosolized medication to the patient breathing circuit  24 , and thus to the patient.  
         [0023]     Referring back to  FIG. 3 , the surrounding exhalation conduit  32  may extend along the same axis as the central inhalation conduit  30  and has a first end  50  for coupling the adapter  20  to the patient breathing circuit  26  and a second end  52  connecting to a depending discharge conduit  54 . The depending discharge conduit  54  is shown as a tube that extends orthogonally from the exhalation conduit  32  and connects to a base  56  of the adapter  20 .  
         [0024]     The base  56  is an outwardly tapered member, which mounts the adapter  20  to the ventilator  22 . The base  56  includes the exhaust port  34 , shown in  FIG. 5 , for discharging breathed gas from the discharge conduit  54 . Discharge conduit  54  is selectively opened and closed by a valve  58  which is preferably part of the adapter  20  and actuated by the ventilator  22 . The structure and function of valve  58  will be described more fully below.  
         [0025]     The exterior of the base  56  of the adapter  20  includes several features designed to facilitate simple removable mounting of the adapter  20  to the ventilator  22 . As shown in  FIG. 3 , the rear portion  60  of the base  56  includes an outwardly extending peripheral lip  62  and a downwardly extending finger  64 . The bottom rim  66  of the base  56  includes an outwardly extending lip  68 . The front portion  70  of the base includes a downwardly extending keyhole  72 . The function and structure of these elements will be further described below.  
         [0026]     Referring briefly to  FIG. 2 , the adapter  20  further comprises a pressure sensing port  74  for interconnecting a monitoring port located proximal to the patient in the breathing circuit with a ventilator pressure sensor (not shown) via flexible tube  76 . As is well known in the art, a pressure sensor output may be connected to a control system, which assures that the breathing pattern produced by the ventilator is the one intended by the patient&#39;s caregiver. The pressure sensing port  74  comprises a nipple  77 , which is sized to fit snugly within the flexible tube  76  for the pressure monitoring port. Air pressure from the patient&#39;s airway is supplied to the tube  76  and passageway  78  ( FIG. 5 ) and ultimately to the ventilator monitor in the direction shown by arrow  79 .  
         [0027]     Referring back to  FIG. 3 , a significant advantage of the adapter  20  of the present invention is that it may be quickly and easily connected to and disconnected from the ventilator  22 . To connect the adapter  20  to the ventilator  22 , the second end portion  40  of the central inhalation conduit  30  is inserted into and retained in a press-fit sealing relation by elastomeric sealing ring  80  on the ventilator outlet  82 . Rim  84  on ventilator outlet  82  engages sealing ring  80 , securing it to ventilator outlet  82 .  
         [0028]     As the second end portion  40  of the surrounding exhalation conduit  32  is inserted into the elastomeric ring  80 , the base  56  of the adapter  20  is simultaneously mounted to surface  86  of ventilator  22 . As shown in  FIG. 3 , the peripheral lip  62  of the base  56  is secured beneath a retaining ledge  88  on the surface  86  of the ventilator  22 . Bottom rim  66  and peripheral lip  68  of the base  56  fits within retaining rim  85  of elastomeric seal  87 . As such, a sealing relationship between the base  56  of the adapter  20  and the surface  86  of the ventilator  22  is formed. Finger  64  of the base  56  further prevents the adapter  20  from disconnecting from the ventilator  22 .  
         [0029]     Referring to  FIG. 4 , as the peripheral lip  62  is inserted beneath the ledge  88 , keyhole member  72  on the front portion  70  of the base is inserted into slot  90  in the surface  86  of the ventilator. Bar  92  is biased in a closed position by spring  94 , and has an angled end surface  73 . As keyhole member  72  is inserted into slot  90 , bar  92  is cammed into an open position when keyhole member  72  engages angled end surface  73 . As keyhole member  72  fully seats into slot  90 , bar  92  is biased back into a closed position by spring  94 , such that the angled end surface  73  passes through keyhole member  72 . Once closed, the bar  92  and keyhole member  72  coupling secures the adapter base  56  to the ventilator  22 .  
         [0030]     Referring back to  FIG. 2 , once the adapter  20  is secured to the ventilator  22 , the caregiver couples the patient breathing circuit  26  to the coaxial breathing conduits  28  and the flexible tube  76  to the pressure monitoring port  74  in a press-fit relationship. If a more permanent coupling is desired, the respective circuits may be bonded to the respective ports so that adapter  20  and breathing circuit  26  form an integral structure. Adapter  20  and breathing circuit  26  may be formed of a plastic material so as to be suitable for single use, disposable applications.  
         [0031]     Referring back to  FIG. 4 , to remove the adapter  20  from the ventilator  22 , the caregiver pulls the tab  96  in the direction of arrow  97  to move the bar  92  away from the adapter  20  and out of the keyhole member  72 . The caregiver then removes the adapter  20  from the ventilator  22  by raising the keyhole member  72  out of the slot  90  on the ventilator surface  86  and then removing the bottom rim  66  from underneath the retaining rim  85  and the second end portion  40  of the central inhalation conduit  30  from the elastomeric ring  80  ( FIG. 3 ). If not bonded together, the respective pressure monitoring tube  76  and patient breathing circuit  26  are manually pulled out of press-fit relationship with their respective ports.  
         [0032]     In use, once the adapter  20  is securely mounted to the ventilator  22 , it provides a conduit for breathable gas to flow from the ventilator  22  to the patient breathing circuit  24 , as shown at arrows  35 , 37  in  FIG. 3 . During the inhalation phase, breathable gas from the ventilator outlet  82  enters the adapter  20  at the second end portion  40  of the central inhalation conduit  30 . From the inhalation conduit  30  the breathable gas is delivered to the central inhalation conduit  42  of the patient breathing circuit  26  and ultimately to the patient&#39;s airway. Referring briefly to  FIG. 5 , as breathable gas is traveling to the patient, aerosolized medicine from the nebulizer  24  is entrained into the gas flow from the nebulizer conduit  44 . Such early introduction of aerosolized medicine into the flow of breathable gas provides better deposition of the aerosolized medicine during the inhalation phase. With the delivery device positioned proximate to the ventilator (i.e. at the distal end of the inspiratory circuit relative to the patient) the bias flow charges the inspiratory circuit during the exhalation phase such that the volume of the inspiratory circuit is used as an aerosol reservoir prior to the delivery to the patient. This advantageously maximizes the aerosolized medicine available to the patient.  
         [0033]     Referring back to  FIG. 3 , once the inhalation phase is complete and the breathable gas is delivered to the patient, the patient exhales and breathed gas is delivered back through the surrounding exhalation conduit  32  of the patient breathing circuit  26 . Breathed gas from the surrounding exhalation conduit  32  enters the depending discharge conduit  54 , as shown by arrows  37 . Close proximity of the exhalation conduit  32  to the inhalation conduit  30  (coaxial in the described embodiment) advantageously facilitates heat transfer from the exhaled gas to warm the inhaled gas/medicine prior to delivery to the patient.  
         [0034]     As shown in  FIG. 3 , the selectively actuated valve  58 , depicted in a closed position, comprises a diaphragm  98  which is actuated by a solenoid-powered finger  100 . During the inhalation phase, the solenoid  102  is actuated and the finger  100  compresses the diaphragm  98  against the valve seat  104  of base  56  to form an airtight seal and prevent breathed gas from escaping the adapter  20 . During the exhalation phase, the solenoid  102  is de-energized and causes the finger  100  to move downward, away from the diaphragm  98 , which allows breathed gas to flow between the diaphragm  98  and the valve seat  104  of the base  56 .  FIG. 5  shows the valve  58  in open position to accommodate breathed gas flow during the exhalation phase. Breathed gas flows from the exhalation conduit  32 , to the depending discharge conduit  54 , and is exhausted out the discharge conduit  54  to atmosphere, as shown at arrow  106 . It should be recognized that breathed gas might also be exhausted to a receptacle or other destination source for breathed gas on a ventilator.  
         [0035]     It will thus be seen that the adapter  20  efficiently interconnects a patient&#39;s breathing circuit to a ventilator. In the embodiment illustrated the adapter efficiently interconnects the patient breathing circuit, a pressure monitor, a source of aerosolized medicine and the ventilator. The adapter  20  couples the source of aerosolized medicine proximate to the ventilator, and thus distal from the patient with respect to the breathing circuit. In this manner, as described above, improved deposition of aerosolized medicine during the inhalation phase results. During the exhalation phase, the delivery device provides a small bias flow rate while the aerosol delivery device continuously atomizes medicine at a fixed rate. With the delivery device placed proximate to the ventilator, the bias flow charges the inspiratory circuit with aerosol during the expiratory phase, thus maximizing the aerosolized medicine available to the patient during the inspiratory phase.  
         [0036]     While this invention is susceptible to embodiments in many different forms, the drawings and the specification describe in detail a preferred embodiment of the invention. They are not intended to limit the broad aspects of the invention to the embodiment illustrated.