Abstract:
An improved flow based incentive spirometer operable through a range of user set flow rates and being adapted to receive a supplemental flow of Oxygen without requiring any change in the calibration of the device or effecting the patient&#39;s monitoring of usage. In this manner the spirometer may be utilized by a range of patients having quite distinct therapy needs. The device also features an integral information display receptacle in the base for storage of operational instructions. A portion of the base is transparent to that the information contained in the storage receptacle can be viewed by a patient while the device is in use, thereby permitting a patient to observe such things as the instructions for proper use of the incentive spirometer while using the device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates in general to respiratory therapy devices and, in particular, to a flow based incentive spirometer to encourage deep breathing exercise for the post-surgical prevention and treatment of atelectasis.  
           [0003]    More specifically, but without restriction to the particular embodiment and/or use which is shown and described herein for purposes of illustration, this invention relates to a flow based incentive spirometer which will provide feedback to patients performing sustained maximal inspiration exercises, and is capable of being used by a patient with a supplemental source of Oxygen.  
           [0004]    2. Description of Related Art  
           [0005]    The use of flow based incentive spirometers for respiratory care and treatment is well known, but the instant spirometer provides specific advantages by addressing appropriate flow ranges through a cost effective, simple design having a number of different flow rate settings, accurate clinical feedback and repeatability, oxygen supplementation capability and ease of use. The present flow based spirometer includes a provision for supplemental oxygen to be provided to a user without interfering with the use of the spirometer throughout a range of flow rates.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of this invention to improve flow based incentive spirometers.  
           [0007]    Another object of this invention is to provide a range of operational flow rates for use by a patient to ensure that an optimum flow rate is being utilized.  
           [0008]    A further object of this invention is to provide a supply of oxygen to the inlet air of a flow based incentive spirometer without the oxygen which is being supplied interfering with the operation or calibration of the spirometer.  
           [0009]    These and other objects are attained in accordance with the present invention wherein there is provided an improved flow based incentive spirometer operable through a range of user set flow rates and being adapted to receive a supplemental flow of Oxygen without requiring any change in the calibration of the device or effecting the patient&#39;s monitoring of usage. In this manner the spirometer may be utilized by a range of patients having quite distinct therapy needs. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0010]    Further objects of this invention, together with additional features contributing thereto and advantages accruing therefrom, will be apparent from the following description of a preferred embodiment of the present invention which is shown in the accompanying drawings with like reference numerals indicating corresponding parts throughout and which is to be read in conjunction with the following drawings, wherein:  
         [0011]    [0011]FIG. 1 is a frontal perspective view of the flow based incentive spirometer;  
         [0012]    [0012]FIG. 2 is a rear perspective view of the flow based incentive spirometer of the present invention;  
         [0013]    [0013]FIG. 3 is a rear elevational view of the invention with portions broken away to better illustrate the internal construction thereof;  
         [0014]    [0014]FIG. 4 is a cross-sectional view of the invention as illustrated in FIG. 3 taken along lines  4 - 4 ;  
         [0015]    [0015]FIG. 5 is a cross-sectional view of the invention illustrated in FIG. 3 taken along line  5 - 5  to better illustrate the internal construction thereof;  
         [0016]    [0016]FIG. 6 is a cross-sectional view of the invention illustrated in FIG. 3 taken along line  6 - 6  to better illustrate the internal construction thereof;  
         [0017]    [0017]FIG. 7 is a top planar view of the invention illustrated in FIG. 3;  
         [0018]    [0018]FIG. 8 is an enlarged perspective view of the dial used in the invention to regulate the air flow; and  
         [0019]    [0019]FIGS. 9 and 10 are cross-sectional views of the invention illustrated in FIG. 3 taken along lines  9 - 9  and  10 - 10 , respectively, to better illustrate the manner in which air flows through the spirometer.  
         [0020]    These and additional embodiments of the invention may now be better understood by referring to the following detailed description of the invention wherein the illustrated embodiment is described. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than limitations on the apparatus and methods of the present invention.  
         [0022]    Referring now to the drawings, there is shown a flow based incentive spirometer  100 , having a handle portion  20 , a base portion  30 , a flow rate determining portion  50 , and a monitoring portion  80 . The handle portion  20  provides a convenient manner for holding and carrying the device, and for attaching the device to a bed, for example, where it can be readily accessible. The base portion  30  provides a platform upon which the device rests, and an integral information display receptacle for containing information such as the written instructions for use of the device which can be conveniently observed by a patient from the top or the bottom of the device when the device is in use. The flow rate determining portion  50  provides a user-selectable range of operative flow rates through which a patient can inhale inspiratory air to obtain the benefits of this therapy and a place for storing a mouthpiece which is used by a patient in withdrawing inspiratory air. The monitoring portion  80  provides a visual display for a patient to monitor the flow rate of inspiratory air during therapy.  
       The Flow Rate Determining Portion  50   
       [0023]    As best illustrated in FIGS. 1, 2,  3  and  8 , the flow rate determining portion  50  includes an inspiratory air withdrawal port  51  formed as an opening in a front wall  53  of the flow rate determining portion  50  through which a patient draws inspiratory air by means of a mouthpiece  91  connected to a flexible Popple tube  93 . The tube  93  is sized to be securely positioned over the connecting port  51  in which may be carried a one-way valve, such as a spider supported flapper valve, to permit a patient to draw inspiratory air through the mouthpiece  91 , but which blocks the passage of expiratory air from passing back into the device. To facilitate convenient access and storage of the mouthpiece  90 , a storage slot is formed by a lipped recess or undercut  58  in the front wall  53  and an outwardly extending offset portion  59  formed in a back wall  54  to receive and retain the mouthpiece  90  therein.  
         [0024]    To meter the flow rate of the inspiratory air being inhaled by the patient, the back wall  54  carries a rotatable dial  60  formed with a plurality of air-flow-control openings  61  having different diameters to form inlet orifices through which a patient withdraws inspiratory air. As best illustrated in FIG. 5, rotation of the dial  60  selectively positions one of the plurality of air-flow-control openings  61  in alignment with an opening  55  in the back wall  54  to control the flow of inspiratory air which is thereby inhaled at a predetermined flow rate which is visually monitored by the patient in a manner to be hereinafter described below.  
         [0025]    As best illustrated in FIGS.  3 - 6 ,  9  and  10 , the spirometer  100  is sealed from the entry of ambient air except through an oxygen port  57 , an indicator channel inlet or opening  82   a  formed in the bottom of an indicator channel  88 , and the opening  55  in the back wall  54  through which inspiratory air is drawn into the spirometer  100  through the particular air-flow-control opening  61  which has been positioned over the aperture  55  formed in the back wall  54 . In this manner, the flow rate of inspiratory air withdrawn from the spirometer  100  by a patient through the inspiratory air withdrawal port  51  maybe regulated by the air-flow-control opening  61  positioned over the aperture  55 , in a manner to be hereinafter described in detail.  
         [0026]    The oxygen inlet port  57 , formed in the back wall  54  to communicate with the interior of the spirometer  100 , is provided to connect a source of oxygen for administration to the patient. The oxygen inlet port  57  extends through the back wall  84  and terminates, as best shown in FIGS. 9 and 10, adjacent to the indicator channel air inlet opening  82   a  through which ambient air is drawn by the patient. In this manner the oxygen inlet port  57  is positioned such that the flow of oxygen is directed into the ambient inspiratory air when the patient inhales through the mouthpiece  91  so that when oxygen is being supplied through the oxygen inlet port  57  the flow of oxygen will not effect the flow rate of the patient created air flow applied to the spirometer  100  when in use. Oxygen discharged into the spirometer  100  through the oxygen inlet port  57  enters the indicator channel  88  through the inlet opening  82   a,  and is drawn upwardly with ambient air entering the indicator channel  88  through the inlet opening  82   a  when the patient inhales through the inspiratory air withdrawal port  51 . Air, with or without supplemental oxygen, passes out from the indicator channel  88  through an indicator channel outlet opening  82   b  formed in the top of the indicator channel  88  to be withdrawn by the patient from the spirometer  100  through the inspiratory air withdrawal port  51 . In this manner, the use of supplemental oxygen will not effect the monitoring of the inspiratory air flow rate through the monitoring portion  80  of the spirometer  100 .  
       The Rotatable Dial  60   
       [0027]    The structure of the rotatable dial  60 , which controls the metering air flow into the flow rate determining portion  50 , is best illustrated in FIG. 8. In the preferred embodiment of this invention the dial  60  is formed with six individual air-flow-control openings  61 , each having a different sized orifice formed therein through which a patient draws a portion of the inspiratory air withdrawn into the spirometer  100 . As illustrated in FIG. 5, the back wall  54  of the spirometer is formed with an opening  55  with which each one of the air-flow-control openings  61  may be selectively aligned by rotation of the dial  60 . The face portion  56  of the back wall against which the dial  60  rotates is recessed in a cup shape to facilitate sealing the rotatable dial  60  against the back wall  54  to minimize or eliminate the flow of inspiratory air into the spirometer except through the particular air-flow-control opening  61  which is aligned with the opening  55  in the back wall  54 .  
         [0028]    To retain the rotatable dial  60  in proper position against the cup-shaped recessed face portion  56  the dial is formed with a hub portion  65 , by which the dial is rotated, having a plurality of resilient tangs  66  extending outwardly therefrom. Each one of the resilient tangs  66  has a tapered shoulder stop  67  formed at the free end thereof. The dial  60  is mounted to the back wall  54  by inserting the tangs  66  through an opening  56   a  in the center of the cup-shaped recess  56  which is closed to the entry of ambient air into the spirometer. A cup-shaped cowling  65   a  is formed on the front wall  53  to receive the hub portion  65  when the hub portion  65  is inserted through the opening  56   a  on the back wall  54 . The cup-shaped cowling  65   a  is then sealed against the back wall  54  to prevent leakage of ambient air into the spirometer through the opening  56   a.  The tangs  66  pass through the opening  56   a,  and the tapered shoulder stops  67  thereof press outwardly against a shoulder  56   b  to retain the rotatable dial  60  against the cup-shaped recess  56 .  
         [0029]    The individual air-flow-control openings  61  are each formed in individual petal-shaped flaps  62  which extend outwardly as cantilevers from the hub  65 . The cantilever construction of the flaps  62  creates a loading force against the cup-shaped recess  56  when the dial  60  is installed into the opening  56   a  of the spirometer, to minimize or eliminate the passage of ambient air into the spirometer  100  except through one of the air-flow-control openings  61 . To this same end, a tapered rim  63  extends about each of the air-flow-control openings  61  and is formed with an outer diameter of a size to sealingly engage with the opening  55  formed in the back wall  54  for minimizing or eliminating the passage of additional ambient air into the spirometer other than through one of the openings  61 .  
       The Monitoring Portion  80   
       [0030]    The monitoring portion  80  permits the patient to monitor the inspiratory air flow rate being applied by the patient&#39;s respiratory system during therapy and, in cooperation with the flow rate determining portion  50 , insures that a patient is receiving the desired therapy. To this end, the monitoring portion  80  includes the “puck” shaped indicator  85  which has a predetermined weight, preferably approximately 1.114 grams, and which is vertically moveable in response to the patient induced air flow between two parallel guide rails  86  (best shown in FIGS. 3,9 and  10 ) formed between a front wall  83  and a back wall  84  of the monitoring portion  80  to define the indicator channel  88 . The indicator channel  88  in which the puck or indicator  85  is vertically moveable in response to the flow rate of patient induced inspiratory air, is formed between the front and back walls  83 ,  84  and the guide rails  86 . The channel  88  is in fluid communication with the inspiratory air port  51  so that as a patient draws inspiratory air through the mouthpiece  91  inspiratory air will be drawn through the indicator channel inlet opening  82   a  and the oxygen port  57  into the indicator channel  88  to draw the indicator puck  85  upwardly as the combined air flows pass out of the indicator channel  88  through the indicator channel outlet opening  82   b  formed at the top thereof.  
         [0031]    To control the flow rate of inspiratory air being withdrawn by the patient through the inspiratory air withdrawal port  51 , the air-flow through the metering aperture  87  formed in one of the parallel guide rails  86  functions to control the upward vertical movement of the indicator  85  as it is drawn upwardly in the channel  88 . To this end a visual indicator  89 , illustrated for example as a smiling face target and a pair of range defining arrowheads, is carried on the front wall  83  of the indicator channel  88  to provide a visual target for assisting the patient in maintaining the indicator puck  85  at the desired target position, the smiling face, which corresponds to a patients inhalation at the desired flow rate. To prevent the indicator puck  85  from being drawn upwardly to the top of the indicator channel  88 , and thereby blocking the indicator channel discharge opening  82   b,  a stop  81   b  is formed at the upper portion of the indicator channel  88  to prevent the puck indicator  85  from closing the opening  82   b.  A similar stop  81   a  is formed at the bottom of the indicator channel  88  to hold the indicator puck  85  off of the indicator channel inlet opening  82   a  in the channel bottom which would inhibit entry of ambient air, and supplemental oxygen if utilized, to facilitate the raising of the indicator puck when inspiratory air is initially withdrawn by the patient.  
         [0032]    Because the puck or indicator  85  is of a fixed size and a fixed weight, preferably about 1.114 grams, and the indicator channel  88  is a fixed cross-sectional dimension, an inspiratory air-flow rate entering the spirometer solely through the indicator channel inlet opening  82   a  can be determined which will be sufficient to cause the indicator puck  85  to be drawn upwardly in the indicator channel, thereby establishing a base air-flow rate. For convenience of manufacturing, it is preferable that this base air-flow rate be established when the rotatable dial  60  is set at the smallest opening. In this manner, the smallest opening can be varied from total occlusion to the flow of air, to an aperture of a size to accomplish the purpose of setting the base air-flow rate from which the size of the other apertures will be formed to provide stepped increments for increased inspiratory air-flow.  
         [0033]    Once the base air-flow rate has been established, the introduction of an additional source of air-flow through an air-flow-control opening  61  of the rotatable dial  60  will require the patient to create an inspiratory air-flow rate in excess of the base air-flow rate in order to raise the puck  85  to a position where the puck will occlude the flow of inspiratory air through the air-flow metering aperture  87 . Preferably, the air-flow-control openings  61  are sized to increase the inspiratory air flow rate in uniform increments, such as 6 liters per minute (l/m). The puck shape of the indicator  85  creates a plus or minus air-flow differential, preferably +/−2 l/m, when the puck is positioned to occlude the flow of inspiratory air through the air-flow metering aperture  87 . This air-flow differential corresponds to the range defining arrowheads marked on the front wall  84  of the indicator channel  88 , with the smiley face portion of the visual target  89  corresponding to a desired flow-rate which will balance the indicator puck  85  for the particular air-flow-control opening  61  selected. Initially when a patient inhales air at a particular flow rate, and the puck-shaped indicator  85  is resting on the bottom stop  81 a, inspiratory air will be drawn from the monitoring chamber  88  through the indicator channel outlet opening  82   b  and the metering orifice  87  causing the puck  85  to rise. As the puck  85  rises in response to the patient&#39;s inhaling, the puck  85  will occlude, or partially occlude, the air-flow metering aperture  87  through which inspiratory air is drawn out of the monitoring chamber  88  into the flow-rate determining portion  50  of the spirometer. When the air-flow metering aperture  87  is so occluded, the puck  85  will stop rising and remain blocking the air-flow metering aperture  87  at a position which corresponds to the position of the smiley face of the visual indicator  89 . Because the indicator  85  is puck shaped, the puck may rise slightly above this blocking position and then “sink” back to the occluding position, or below, and then be drawn up again. This “floating” of the puck  85  relative to occluding the air flow through the air-flow metering aperture  87  has been found to generate the +/−2 l/m air-flow differential and is marked by the points of the arrow heads of the indicator  89 .  
         [0034]    When it is desired to increase the flow-rate at which a patient will inhale inspiratory air, the rotatable dial  60  is rotated until a larger air-flow-control orifice  61  is positioned adjacent to the opening  55 . This will increase the air-flow rate required to be inhaled by the patient in order to “balance” the puck  85  at the smiley face portion of indicator  89 . In this manner a patient can utilize the spirometer throughout a range of different intensity deep breathing exercises, and the spirometer also can be utilized by different patients having a range of different capabilities for inhaling inspiratory air.  
       The Base Portion  30   
       [0035]    In order to permit the patient to conveniently observe the instructions for use of the device, and to maintain those instructions in an accessible fashion, the base portion  30  is formed of a transparent material with an opening  31  in a skirt portion  32  of the base, best illustrated in FIGS. 3 and 4. The opening  31  is formed between the top of the base and base pads  35  upon which the device stands. In this manner documentary materials, such as the instructions  36  for the use of the device, can be inserted into the base through the opening  31 , and will be supported by the base pads  35  above the surface upon which the device is placed. Because the base is preferably formed of a transparent material, the instructions may be folded in a manner so that they are observable through the top and the bottom of the base to facilitate a patient&#39;s reference to them while the device is in use.  
       The Handle Portion  20   
       [0036]    The handle portion  20  includes a closed portion forming a handle  21  enabling a patient to grasp and carry the spirometer  100  and an open hook projection  23  formed at the uppermost part of the handle portion  20  to enable the spirometer to be conveniently hung over a rail or a portion of a bed for convenient access by patients that are so confined.  
         [0037]    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: