Abstract:
An oscillatory positive expiratory pressure respiratory therapy device which may be incorporated into the expiratory limb of a ventilator circuit. Accordingly, this device allows a patient on a ventilator to be subjected to positive expiratory pressure (PEP) therapy combined with airway oscillation and intermittent air flow acceleration while allowing the oscillatory PEP respiratory therapy treatment to be bypassed without interrupting the integrity of the ventilating circuit once the device has been installed in the ventilator circuit. In this manner, all expiratory air in the ventilator circuit is accounted for, the expiratory air volume may be accurately monitored and the ventilator circuit does not have to be broken for insertion or removal of the device.

Description:
[0001]    This application is a continuation in part of application Ser. No. 09/449,208 filed Nov. 24, 1999. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates in general to a single patient use, positive oscillatory expiratory pressure respiratory therapy device which includes an air-flow bypass and, in particular, to a positive oscillatory expiratory pressure respiratory therapy device for incorporation into the expiratory limb of a ventilator circuit, and operable by a patient through passive exhalation during the expiratory cycle. The device when in an “on” or “active” mode of operation imposes an oscillatory expiratory air pressure on the patient during exhalation for the purpose of loosening secretions, and in the “off” or “bypass” mode of operation permits free flow of air through the device with minimal or no pressure drop.  
           [0004]    2. Description of Related Art  
           [0005]    Persons who suffer from pulmonary problems that result in large amounts of mucus being produced in the lungs often require assistance in the removal of these secretions. If these secretions are allowed to remain in the lungs, airway obstruction occurs resulting in poor oxygenation and possible pneumonia and/or death. One of the clinically recognized treatments for this condition is a technique known as positive expiratory pressure therapy or PEP. With PEP therapy, a patient exhales against a resistance to generate expiratory pressure at a substantially constant rate of flow. Prescribed expiratory pressures are generally in the range of 10-20 cm of H 2 O, although other pressure ranges and pressures can be used.  
           [0006]    In the use of PEP therapy, a patient breaths through an orifice restricter to generate a positive pressure in the lungs during exhalation, with the pressure falling to zero at the end of the exhalation. By selection of the proper-sized orifice, a given pressure is determined for the exhalation flow rate generated by an individual patient. This extended, substantially constant, flow of elevated-pressure exhalation has been shown to be effective for moving secretions trapped in the lungs to the larger airways where the secretions can then be removed through coughing. It has also been found that in the treatment of patients having chronic obstructive pulmonary disease (COPD), chronic bronchitis, cystic fibrosis, atelectasis, or other conditions producing retained secretions, treatment with PEP therapy is improved by combining positive expiratory pressure therapy with airway oscillation and intermittent air-flow acceleration. To this end a hand-held, single patient use, positive expiratory pressure respiratory therapy device was developed by assignees of the present invention, and is the subject matter of a co-pending application, Ser. No. 09/449,208, filed Nov. 24, 1999 for “POSITIVE EXPIRATORY PRESSURE DEVICE”.  
           [0007]    The present invention comprises a positive oscillatory expiratory pressure respiratory therapy device which is incorporated into the expiratory limb of a ventilator circuit. Accordingly, this device allows a patient on a ventilator to be subjected to positive expiratory pressure therapy combined with airway oscillation and intermittent air flow acceleration while allowing this respiratory therapy treatment to be bypassed without interruption once the ventilator circuit has been established. In this manner, all expiratory air in the ventilator circuit is accounted for, and the expiratory air volume may be accurately monitored.  
           [0008]    As is known to respiratory therapy healthcare providers, the volume of expiratory air in a ventilator circuit is closely monitored. Once this invention has been installed into the expiratory limb of the ventilator circuit, the ventilator circuit never needs to be broken enabling the healthcare provider to accurately account for all expiratory air and maintain the integrity of the ventilator circuit. In addition, the device is constructed such that any condensation forming in the device will drain out from the housing because of the interior design which facilitates the flow of condensate out from the device into the ventilator circuit. Furthermore, the transparency of the housing permits inspection of the interior to insure that condensate is not being retained in the device.  
           [0009]    As is also known to respiratory healthcare providers, the use of an oscillatory expiratory pressure imposed on the patient must be carefully controlled. To this end, a ventilator circuit includes apparatus to closely monitor the positive end expiratory pressure (PEEP). Accordingly, the amount of expiratory air pressure buildup in the opening pressure cycle for producing the airway oscillation, and intermittent air flow acceleration, must be carefully controlled. To this end, during the “on” cycle or “active” mode of operation, the present invention is designed such that oscillatory expiration occurs throughout the entire expiratory air cycle until the expiratory air pressure decreases to the point where oscillation can no longer occur, but never exceeds the allowable PEEP.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention is directed to overcoming one or more of the problems or disadvantages associated with the relevant technology. As will be more readily understood and fully appreciated from the following detailed description of a preferred embodiment, the present invention is embodied in a positive oscillatory expiratory pressure respiratory therapy device for incorporation into a ventilator circuit. The device includes a bypass for selectively directing the expiratory air discharged from a patient through the device for oscillatory PEP treatment or bypassing the device to discharge the patient&#39;s expiratory air directly through the ventilator circuit. In this manner, once the device is installed into a ventilator circuit, the integrity of the ventilator circuit always remains intact and the patient expiratory air volume may be accurately monitored.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0011]    Further objectives of the invention, together with additional features contributing thereto and advantages accruing therefrom, will be apparent from the following description of a preferred embodiment of the invention which is shown in the accompanying drawings with like reference numerals indicating corresponding parts throughout, wherein:  
         [0012]    [0012]FIG. 1 is a perspective view of the assembled invention;  
         [0013]    [0013]FIG. 2 is an exploded perspective view of the invention with portions removed to better illustrate the internal structure thereof;  
         [0014]    [0014]FIG. 3 is an exploded perspective view of the rocker and platform portions of the invention to better illustrate the manner in which a user produces an oscillatory positive expiratory pressure and the manner in which the magnitude and frequency of the oscillations can be adjusted;  
         [0015]    [0015]FIGS. 4, 5 and  6  are, respectively, a side profile, top elevation and front profile view of the platform portion of the invention to illustrate a portion of the structure forming the non-linear orifice and a portion of the structure for adjusting the magnitude and frequency of the oscillatory expiratory air pressure;  
         [0016]    [0016]FIGS. 7, 8 and  9  are, respectively, a side profile, top elevation and front profile view of the rocker portion of the invention with portions broken away to show the internal structure which is used in combination with the platform structure of FIGS.  4 - 6  form the non-linear discharge orifice and create the oscillatory expiratory air pressure;  
         [0017]    [0017]FIG. 10 is a perspective view of an adjustment dial portion of the invention to better illustrate the manner in which the platform portion illustrated in FIGS.  4 - 6  is positionable relative to the rocker portion illustrated in FIGS.  7 - 9  to determine the movement of the rocker portion for controlling the oscillatory frequency and pressure;  
         [0018]    [0018]FIG. 11 is an enlarged view of an end portion of the upper housing of the invention to better illustrate the manner in which the movement of the adjustment dial illustrated in FIG. 10 is controlled;  
         [0019]    [0019]FIG. 12 is a cross-sectional view of the flow tube portion of the invention taken along the lines  12 - 12  of FIG. 3;  
         [0020]    [0020]FIG. 13 is an enlarged perspective view of the knob and stem portion of an air-flow control valve, the operation of which selectively controls the air flow movement through the air-flow tube between the oscillatory pressure portion or bypass portion of the invention;  
         [0021]    [0021]FIG. 14 is a graphical representation of the operation of a ventilator circuit with the invention in the “off” or “bypass” mode; and  
         [0022]    [0022]FIG. 15 is a graphical representation of the operation of the invention in the “on” or “active” mode. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    Referring now to the drawings, there is illustrated in FIGS. 1 and 2 an oscillatory positive expiratory pressure (PEP) respiratory therapy device  1000  which may be incorporated into the expiratory limb of a ventilator circuit for applying oscillatory positive expiratory air pressure (PEP) therapy to a patient, or for bypassing the oscillatory PEP treatment by coupling the expiratory air flow directly to the remainder of the ventilator circuit.  
         [0024]    The oscillatory PEP device  1000  is selectively actuated between two modes of operation, an “on” or “active” mode in which oscillatory PEP therapy is applied, and an “off” or “bypass” mode in which the expiratory air bypasses the therapy applying portion of the device, by operation of an air-flow control valve  100 . The air-flow control valve  100  is carried within an air-flow tube  200  and is manually positionable to selectively control the passage of expiratory air through either the oscillatory PEP inducing portion or to bypass that portion of the device.  
         [0025]    When the air-flow control valve  100  is in a closed position, blocking free through-flow of the expiratory air, the “on” or “active” mode of the device  1000 , expiratory air is passed to and through an upper housing portion  300  of the device  1000  in which is enclosed an expiratory-air-driven oscillatory rocker assembly  400 . The expiratory-air-driven oscillatory rocker assembly  400  comprises two portions, a rocker portion  440  and a rocker support or platform portion  480  which act together in creating the oscillatory PEP therapy and are best illustrated in FIGS.  2 - 9 . The details of the structure and operation of this oscillatory PEP portion of the device will be described in detail hereinafter.  
         [0026]    To control the magnitude and frequency of the oscillatory pressure applied to a patient, a rotatable frequency control dial  350  is positioned at and carried by one end of the housing  301  in which the rocker assembly  400  is contained. By operation of the adjustable frequency control dial  350  in a manner to be hereinafter described, the relative positioning between the oscillatory PEP inducing portions of the oscillatory rocker assembly  400 , the rocker portion  440  and the rocker support portion  480 , are adjusted to control the magnitude and frequency of the oscillatory expiratory air pressure.  
         [0027]    The expiratory-air-driven oscillatory rocker portion  440  is best illustrated in the exploded view of FIG. 3, and in more detail, in FIGS.  7 - 9 . The rocker support portion  480 , which functions in cooperation with the rocker portion  440  to produce an oscillatory expiratory air flow and pressure, is also illustrated in the exploded view of FIG. 3, and in more detail in FIGS. 4 through 6. The expiratory-air-driven oscillatory rocker portion  440  and the rocker support portion  480 , when assembled together, form the rocker assembly  400 .  
         [0028]    The rocker assembly  400  is supported on the air-flow tube  200  and carried within the upper housing  300  which forms a sealed chamber with the air-flow tube  200 . In this manner, the rocker assembly  400  functions to create an oscillatory positive expiratory air pressure and flow rate in response to a patient&#39;s exhalation when the air-flow control valve  100  is closed, the “on” or “active” mode of operation, and the patient&#39;s expiratory air is thereby directed to and through the rocker assembly  400 .  
         [0029]    As best shown in FIGS. 3 and 12, there is illustrated the air flow tube  200  having a first or input end  201  for attachment into the expiratory air limb of a ventilator circuit, and a second or output end  202  through which expiratory air passes to the remainder of the expiratory leg of the ventilator circuit. The input and output ends  201  and  202 , respectively, are sized as standard female and male fittings so that the air flow tube  200  can be used with tubing of standard size used in a ventilator circuit, frequently 22 mm i.d. and 22 mm o.d. The air flow tube  200  has an opening  203  in the top portion thereof through which expiratory air will be passed to the oscillatory rocker assembly  400  for creating the oscillatory PEP therapy for the patient in a manner to be hereinafter described in detail. To this end, the air flow tube  200  carries the air-flow control valve  100  within the interior of the air flow tube  200  whereby the air-flow control valve  100  is operable between a closed position, wherein the air flow is directed into the housing  300  and through the rocker assembly  400  during the “on” or “active” mode of operation, and an open position, the “off” or bypass mode of operation, whereby the oscillatory PEP therapy is bypassed and the expiratory air is discharged through the remaining portion of the expiratory leg of the ventilator circuit. The selective rotational movement of the air-flow control valve  100  is effected by an air-flow control valve knob  105  extending outwardly from the bottom of the air flow tube  200 .  
         [0030]    As best illustrated in FIGS. 2, 3,  12  and  13 , the air-flow control valve  100  has a tapered circular portion  102  which is carried within the air-flow tube  200  to be rotated between an “on” position blocking the through flow of air through the air-flow tube  200 , as illustrated in FIG. 12, and an “off” portion wherein the tapered circular portion  102  is rotated 90° to permit the free flow of air through air-flow tube  200 . These two positions correspond, respectively, to the “active” and “bypass” modes of operation.  
         [0031]    Rotational movement of the air-flow valve  200  between “on” and “off” positions is effected by turning a knob  105  connected to the tapered circular portion  102 . As best illustrated in FIGS. 2, 3,  12 , and  13  knob  105  includes a stem  106  which extends through the air-flow tube  200  and the tapered circular portion  102  between guides  103  formed thereon. The distal or terminal end of the stem  106  includes a tip  107  which engages with a suitable recess in the air-flow tube  200  to permit the knob  105 , and thereby the tapered circular portion  102 , to be rotated between the “on” position blocking the through-flow of air through the air-flow tube  200  and an “off” position permitting the free through-flow of air through the air-flow tube  200 . An arrow-shaped indicator  109  is formed on the knob  105  to permit the visual confirmation of the “on” and “off” modes of operation. The air-flow control valve  100  is sized to conform to the cross-sectional shape of the air-flow tube  200  and is rotatable between the closed and open positions to control the “on” and “off” modes of the oscillatory PEP treatment, respectively.  
         [0032]    When the air-flow control valve  100  is positioned for operation of the device in the “on” or “active” mode of operation, air flow passing directly through the air-flow tube  200  is blocked, and an air flow path is created which extends from the inlet  201  of the air-flow tube  200  out through the opening  203  in the air-flow tube into the housing  300  to be applied to the oscillatory rocker assembly  400  for creating the oscillatory PEP therapy applied to the patient.  
         [0033]    As best illustrated in FIGS.  2 - 9 , the rocker portion  440  is balanced for pivotal movement about pivot pins  441  on spaced pivot supports  481  formed on a platform  485  of the rocker support portion  480 . The pivot pins  441  form a transverse pivot axis for the rocker portion  440  which lies in a plane above and extends transverse to the longitudinal axis of the platform  485 . The pivot pins  441  are limited in their axial and vertical movement by a pair of locking guides  482 , carried by the platform  485  and one of which is positioned adjacent each of the pivot supports  481  to maintain the pivot pins  441  in their proper position on the pivot supports  481 . In this manner the rocker portion  440  is pivotal relative to the rocker support portion  480  regardless of the orientation of the device  1000 , allowing the oscillatory PEP device  1000  to function regardless of its orientation in use. A balance pad  442  and balancing cylinder  443  are formed at one end of a rocker  445  to balance the weight of a cone-shaped air-flow closure member  447  and a pin of magnetically attractable material, such as a steel pin  448  both of which are carried at the opposite end of the rocker  445 . The pin  448  is carried at the distal end of the rocker  445  by a plurality of gripping fingers  446  which partially encircle the pin  448  for holding the pin in a position to be exposed to the magnetic field of a magnet  488  carried on the platform  485 . The air-flow closure cone  447  is sized and positioned on the rocker  445  to be periodically inserted into a tapered bell-shaped or trumpet-shaped air-discharge outlet  487  formed in the platform  485  to create the oscillatory PEP when expiratory air is discharged through the opening  203  in the air-flow tube  200  into the housing  300 . As best illustrated in FIGS. 3 and 4, the interior of the air-discharge outlet  487  has a non-linear taper or bell-shaped interior surface to form a non-linear air discharge outlet for creating the oscillatory PEP therapy in response to the pivotal movement of the rocker cone  447  in to and out therefrom. In this manner the discharge outlet  487  is periodically closed and re-opened allowing the expiratory air discharged there through to be returned to the air-flow tube  200  at a position downstream of the closed air-flow control valve  100 . Accordingly, all of the expiratory air passed into the oscillatory PEP device  1000  when operating in the “on” or “active” mode will be returned to the ventilator circuit through the discharge outlet  207  passing out and thereby through the air-flow tube discharge outlet end  202 .  
         [0034]    The oscillatory rocker assembly  400  is secured on the air-flow tube  200  and positioned within the housing  300  by means of a plurality of positioning tangs  484  which extend downwardly from the platform  485  and are best illustrated in FIGS. 4 and 6. These tangs  484  are secured in channels  284  extending upwardly from the top of the air-flow tube  200  to securely position the oscillatory rocker assembly  400  onto the air-flow tube  200 . In this manner the non-linear tapered, bell-shaped discharge outlet  487  carried by the platform  485  aligns with a cowling  287  of the complementary opening  203  in the air-flow tube  200  into, and through which, the bell-shaped discharge outlet  487  extends. Another tang  384  extends downwardly from the interior of upper portion  304  of the housing  300  and passes through an aperture  444  in the rocker  445  to press downwardly against the platform  485  thereby securing the oscillatory rocker assembly  400  in the proper position on the air-flow tube  200  when the housing  300  is secured thereto.  
         [0035]    To create the periodically interrupted discharge of expiratory air for applying the oscillatory PEP therapy to a patient, the magnetically attractable material or steel pin  448  is carried on the pivotal rocker  445  at a position in operative proximity to the magnet  488  carried by the rocker support portion  480 . The magnet  488  is carried in a magnet support pocket formed by a plurality of gripping or centering fingers  492 . The magnet support pocket is formed at the free end of a vertically positionable U-shaped carrier  490  which is cantilevered from the platform  485 . In this manner, the magnet is positioned in proximity to the steel pin  448  to apply a preselected magnetic attraction force thereto. To this end the U-shaped carrier  490  has a vertical positioning link  494  extending vertically upward from a position adjacent to the magnet support pocket  491  and terminating at a distal end in a tip  495  which engages a recess  395  in the oscillation frequency control dial  350 . Rotation of the frequency control dial  350  controls the frequency of the oscillations by which the PEP treatment or therapy is applied in accordance with the desires of the healthcare provider. The recess  395  is offset from the center of rotation of the frequency control dial  350  (best illustrated in FIG. 10) such that rotation of the dial  350  will raise or lower the tip  495 , engaged therein, thereby moving the magnet  488  towards or away from the steel pin  448  to vary the magnetic attractive force there between.  
         [0036]    While the device  1000  will function to provide an oscillatory PEP pulse without the use of the magnetic field between the magnet  488  and the steel pin  448  because of the opening and closing of the tapered non-linear discharge outlet  487  due to the movement of the tapered cone-shaped air-flow closure  447  induced in response to the patient&#39;s discharge of expiratory air, the use of the magnetic field permits the device  1000  to provide an adjustable range in the pressure of the patient&#39;s expiratory air discharge required to create the oscillatory positive expiratory pressure pulses. By using the magnetic field attraction, the patient&#39;s expiratory air pressure required to create the oscillations can be controlled to insure that the positive end expiratory pressure (PEEP) level set by the ventilator circuit is not exceeded. In addition, the magnetic field attraction permits the device  1000  to be operated in any spatial orientation.  
         [0037]    To assist a patient or the healthcare provider in using the device  1000  once the proper magnetic field has been set, a plurality of indicia  310  are spaced along the top of the housing  300 . These indicia  310 , in combination with a base reference point  360  on the frequency adjusting dial  350 , are used to ensure that the correct setting is being maintained after the healthcare provider has established the desired level for treatment. To minimize the occurrence of the rotatable adjusting dial  350  being unknowingly rotated, a series of tooth-like projections  315  are formed on the face of the housing  300  (best seen in FIG. 11) which engage with a mating tooth  355  formed on the interior of the rotatable frequency adjusting dial  350  to provide resistance to movement and an audible sound when the dial  350  is rotated. A pair of stops  317  are formed on the front of the housing  300  which, in combination with a stop  357  formed on the interior of the frequency adjusting dial  350 , limit the rotational movement of the dial  350  relative to the housing  300 .  
         [0038]    Industrial Applicability  
         [0039]    During use of the variable frequency or oscillatory PEP device  1000  in a ventilator circuit in the “active” mode, the air-flow control valve  100  is closed and a patient&#39;s expiratory air is delivered through the input end  201  of the air-flow tube  200  and passes through the opening  203  to the oscillatory rocker assembly  400 . Accordingly, the expiratory air pressure is applied against the cone-shaped closure  447  of the rocker assembly  400  which forms a closure of the non-linear discharge opening or orifice  487 . The pressure of the patient&#39;s expiratory air will raise the cone-shaped closure  447 , causing the rocker portion  440  to pivot about the pivot pins  441  against the force of the magnetic field between the magnet  488  carried on the pivotal rocker support portion  480  and the steel pin  448  carried on the rocker assembly  400 . As the cone-shaped closure  447  moves upwardly in response to the increasing expiratory air pressure, the constant taper of the conical shape in conjunction with the bell-shaped non-linear taper of the non-linear discharge opening or orifice  487  increases the effective discharge area thereby decreasing the air pressure applied against the cone-shaped closure  447  and reducing the upward acceleration of the rocker arm  445 . When the magnetic force and the Coanda effect of the air flow over the bell-shaped or non-linear tapered interior of the discharge outlet  487  overcome the expiratory air pressure applied to the tapered cone-shaped closure  447 , the closure  447  will again begin to move downwardly and accelerate into the bell-shaped non-linear-tapered discharge orifice  487 . As the cone descends into the air flow path through the discharge outlet or orifice  487 , the annular flow area diminishes reducing the airflow rate and increasing the air pressure. This continues until the downward momentum is overcome and the cone  447  resumes its upward acceleration. Maximum pressure is obtained at this point and another cycle begins. The oscillatory air pressure and air flow during an inhalation and an exhalation cycle when the device is in the “on” or “active” mode of operation is illustrated in the graph of FIG. 15.  
         [0040]    Positioning the air-flow control valve  100  in an open position, the “off” or “bypass” mode of operation, permits the expiratory air discharged by the patient to bypass the oscillatory rocker assembly  400  and flow directly through the device  1000  and into the rest of the ventilator circuit with no perceptible drop in air pressure because of the substantially unrestricted flow of air through the air-flow tube. Accordingly, once the device  1000  has been installed into the ventilator circuit, it never needs to be removed greatly facilitating the monitoring of the volume of air circulated through the ventilating circuit. The device  1000  will then operate in a passive state allowing the patient to breath in a manner by which the device  1000  will not effect the operation of the ventilator circuit. The passive air pressure and flow rate during an inhalation and exhalation cycle when the device  1000  is in the bypass mode of operation is illustrated in the graph of FIG. 14.  
         [0041]    While this invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, the structure of which has been disclosed herein, it will be understood by those skilled in the art to which this invention pertains that various changes may be made and equivalents may be substituted for elements of the invention without departing from the scope of the claims. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed in the specification and shown in the drawings as the best mode presently known by the inventors for carrying out this invention nor confined to the details set forth, but that the invention will include all embodiments modifications and changes as may come within the scope of the following claims: