Abstract:
A drainage device comprising an improved vacuum regulator assembly is disclosed which includes an adjustable knob for indicating the degree of vacuum being applied to the device from a number of incident viewing angles. Similarly, a vacuum indicator assembly is provided for indicating the presence or absence of vacuum being applied to drainage device. The indicator assembly provides an indication of vacuum inside drainage device from many viewing angles and includes a base defining a recess having a slanted surface with a vacuum symbol which is selectively masked by a collapsible thimble when vacuum is applied or removed from the drainage device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims benefit of U.S. Provisional Application No. 60/251,724, filed Dec. 6, 2000. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a chest drainage system, and particularly to a dry chest drainage apparatus for suctioning gases and liquids from the chest cavity of a patient. More specifically, the present invention relates to a vacuum setting and indication system for a dry chest drainage apparatus which permits viewing by the user from a number of directions. 
   2. Prior Art 
   A chest drainage device is an apparatus for suctioning gases and liquids from the pleural cavity of patients. The pleural cavity lies within the rib cage above the diaphragm and is surrounded by the pleural membrane. The pleural cavity contains both lungs, which in their normal expanded state fill the pleural cavity. Several conditions and diseases such as interventional surgery, trauma, emphysema and various respiratory infections can cause build up of liquid and gases around the lungs in the intrapleural space. When this happens, it causes the lungs to collapse to a volume much less than that of the pleural cavity, thereby severely impairing the breathing functions of the patient. The lungs can be re-expanded to their normal state to fill the pleural cavity by draining the liquid and gases from the intrepleural space using a chest drainage device. 
   There are many kinds of chest drainage devices used to drain the intrapleural space of a patient. One kind of drainage device, sometimes referred to as a “three-bottle” type, is illustrated in U.S. Pat. No. 3,363,626 to Bidwell et al. entitled “Underwater Drainage Apparatus”. The “three-bottle” type drainage device has three interconnecting chambers which comprise: (1) a collection chamber for collecting liquids and gases suctioned from the patient&#39;s pleural cavity; (2) an underwater seal chamber which communicates with the collection chamber and has a water seal which acts as a one way valve for passing gases from the patient&#39;s pleural cavity to the atmosphere; and (3) a suction control chamber for limiting the maximum suction (or negative pressure) applied to the patient&#39;s pleural cavity. 
   Another kind of drainage device is the “four-bottle system” which includes the three chambers of the “three-bottle system” and adds a fourth chamber, referred to as a manometer chamber, which provides an accurate indicia of the level of suction being applied to the cavity to be drained. However, the “four-bottle system” suffers from several deficiencies. In particular, the suction control chamber is noisy due to bubbling of atmospheric air through the liquid maintained therein; and the system is somewhat bulky. 
   With increased awareness of the anxiety-provoking nature of noise in the hospital environment, a mechanical regulator to adjust the level of vacuum applied was provided as a substitute for a liquid filled suction control chamber of the prior art. U.S. Pat. No. 4,372,336 to Cornell discloses a mechanical regulator for a drainage device having a liquid-filled manometer chamber which provides a visual indication of the vacuum level present in the device. Although the drainage device of Cornell is an improvement over prior art drainage devices, such devices could still be further improved. For example a drainage device having a dry system containing no liquid in either the suction control chamber or manometer chamber would be desirable. 
   Drainage devices employing a dry system for draining liquid and gases from a patient&#39;s pleural cavity use a mechanical regulator to both adjust the level of vacuum to the device as well as a means of indicating the actual degree of vacuum being applied to the drainage device. Such drainage devices normally have a dial or knob disposed along either the side or front wall of the drainage device casing for adjusting the degree of vacuum by rotating the dial or knob in one direction. U.S. Pat. No. 4,784,642 to Everett, Jr., et al. and U.S. Pat. No. 5,989,234 to Valerio, et al. are illustrative of drainage devices using a mechanical regulator in the form of a rotatable dial or knob on the front or side of the device to adjust the level of vacuum in the device. However, such prior art adjustment means are difficult to view from different angles and are cumbersome to operate since these mechanisms have mechanical arrangements that can become stuck or require extra effort to operate, while the vacuum setting indicia surrounding the knob dial can only be viewed from the front or side of the device. 
   Some drainage devices are also provided with a vacuum indicator assembly to visually indicate the presence of vacuum inside the drainage device. Vacuum indicator assemblies can be in the form of an extendable baffle, a floating ball chamber or an inflatable masking diaphragm which provides a selective visual signal to the user of proper vacuum in the drainage device. Similar to the vacuum indicator assembly disclosed in U.S. Pat. No. 4,747,843 to Felix et al., vacuum indicator assemblies of the prior art are recessed along the front or top portions of the drainage device, thereby making them strictly viewable from a limited angle. 
   The drawback of having either the vacuum indicator assembly or vacuum setting indicia being recessed inside the drainage device along either the side or top portion thereof is that a user may not be able to clearly view either the indicator assembly or setting indicia when the drainage device is placed on the floor or a desk, or suspended from a pole. In other words, when the drainage device is placed on the floor, the user cannot view the vacuum indicator assembly if the assembly is located along the side of the device, and thereby hidden from view. 
   Therefore, there is a need in the art for a drainage device having a mechanical regulator which gives a clear indication of the vacuum level setting to the user from a number of angles. There is a further need in the art for a drainage device having a vacuum indicator assembly that is clearly viewable from many directions by the user. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   One feature of the present invention is to provide a control knob for a mechanical regulator of a drainage device having vacuum setting indicia that is viewable from a number of angles. 
   Another feature of the present invention is to provide a drainage device having a vacuum indicator assembly that is viewable from more than one direction. 
   A further feature of the present invention is to provide a drainage device having vacuum setting indicia that includes a raised marker. 
   Yet another feature of the present invention is to provide a drainage device having vacuum setting indicia placed along a slanted surface. 
   Another further feature of the present invention is to provide a drainage device having a vacuum indicator assembly that is raised above the casing of the device. 
   In brief summary, the present invention overcomes and substantially alleviates the deficiencies present in the art by providing a vacuum setting and indication system for a waterless drainage device having a vacuum setting indicia and a vacuum indicator assembly which are viewable from a number of directions. 
   Preferably, the drainage device comprises a unitary casing having a collection chamber for the collection of liquids and gases, a water seal chamber for preventing evacuated gases from reentering the collection chamber, and a mechanical regulator for regulating the degree of vacuum inside the drainage device. The collection chamber is in fluid flow communication with a patient&#39;s pleural cavity through a catheter having one end disposed therein and the other end attached to a collection port of the collection chamber. The water seal chamber defines a compartment having one end in communication with the collection chamber and the other end in communication with a source of vacuum. A water seal is disposed at the bottom of the water seal chamber and prevents the reflux of evacuated gases back into the collection chamber during a sudden high negative pressure condition in the collection chamber, for example, when a patient takes a quick and deep inhalation. 
   The mechanical regulator is preferably a single stage regulator which includes a housing that encloses a suction regulating chamber. The housing further includes a regulator control knob which operates to adjust the level of vacuum applied to the drainage device. According to one aspect of the present invention, the control knob has a slanted surface having a plurality of vacuum setting levels printed thereon which are viewable from either the top or sides of the drainage device. The control knob further includes a textured arrow which illustrates the direction the knob is turned in order to increase the level of vacuum and a raised marking arrow for indicating the exact degree of vacuum being applied to the drainage device. 
   The drainage device further includes a vacuum indicator assembly for giving the user a visual indication of the presence of vacuum in the device. The vacuum indicator assembly comprises a base attached to the top portion of the drainage device in communication with the collection chamber with the base defining a raised tubular member which extends upwardly from the base. The free end of the raised tubular member defines a recess having a slanted surface with an arrow or other appropriate vacuum symbol marked thereon for indicating the presence of vacuum in the drainage device when visible and an aperture which is in fluid flow communication with the vacuum from the collection chamber. The vacuum indicator assembly further comprises a semi-transparent, flexible thimble which encases the raised tubular member in a fluid tight seal such that the thimble is placed in an inflated condition when vacuum is not present within the drainage device or in a deflated condition when vacuum is present within the device. In the inflated condition with no vacuum applied to the drainage device, the thimble masks the slanted surface such that the vacuum symbol is hidden from view, while in the deflated condition the flexible thimble collapses onto the slanted surface and exposes the vacuum symbol to view, thereby indicating the presence of vacuum in the drainage device to the user. Finally, a casing houses the thimble and base so that the vacuum indicator assembly is properly oriented relative to the drainage device. 
   These and other objects of the present invention are realized in the preferred embodiment, described by way of example and not by way of limitation, which provides for a dry drainage device with a vacuum setting and indication system viewable from a number of directions. 
   Additional objects, advantages and novel features of the invention will be set forth in the description which follows, and will become apparent to those skilled in the art upon examination of the following more detailed description and drawings in which like elements of the invention are similarly numbered throughout. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of the drainage device according to the present invention; 
       FIG. 2  is a top view of the drainage device according to the present invention; 
       FIG. 3  is a back view of the drainage device according to the present invention; 
       FIG. 4  is a side view of the drainage device according to the present invention; 
       FIG. 5  is a front view of the drainage device illustrating the liquid and air flow pathways according to the present invention; 
       FIG. 6  is a cross sectional view of the drainage device, taken along line  6 — 6  of  FIG. 5 , illustrating the air flow pathway to a vacuum source according to the present invention; 
       FIG. 7  is an enlarged perspective view of a vacuum regulator assembly and a vacuum indicator assembly according to the present invention; 
       FIG. 8  is a partial cut-off view of the vacuum indicator assembly according to the present invention; 
       FIG. 9  is a perspective view of a cover of the vacuum indicator assembly according to the present invention; 
       FIG. 10  is a perspective view of a thimble of the vacuum indicator assembly according to the present invention; 
       FIG. 11  is a perspective view of a base of the vacuum indicator assembly according to the present invention; and 
       FIG. 12  is a cross sectional view of the vacuum indicator assembly, taken along line  12 — 12  of  FIG. 7 , according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings, the preferred embodiment of the drainage device of the present invention is illustrated and generally indicated as  10  in  FIG. 1 . Drainage device  10  comprises a casing  12  having a top wall  104 , a bottom wall  106 , front and rear walls  108  and  110  ( FIG. 4 ), respectively, and end walls  112  and  114 . Casing  12  further comprises a collection chamber  14  for the collection of fluids, a water seal chamber  16  for preventing reflux of evacuated gases back into collection chamber  14 , and a suction control chamber  18  in communication with a vacuum regulator assembly  22  for regulating the degree of vacuum inside drainage device  10 . As shown, casing  12  also comprises interior partitions  116 ,  118 ,  120 ,  122 , and  124  ( FIG. 1 ) which are parallel to end walls  112  and  114 , and a partition  126 , which is parallel to front and rear walls  108  and  110 , that divide the interior of casing  12  into collection chamber  14 , water seal chamber  16 , suction control chamber  18  as well as a number of other chambers and compartments as shall be discussed in greater detail below. 
   The top wall  104  of drainage device  10  comprises a negative pressure relief valve  28  for venting excess negative pressure from within casing  12 , a collection port  26  for attachment to infusion tubing  32 , vacuum regulator assembly  22  for the mechanical regulation of vacuum inside drainage device  10 , and a vacuum indicator assembly  24  for giving a visual indication to the user of proper vacuum being applied to collection chamber  14 . A handle  46  is also provided along top wall  104  for handling and transporting drainage device  10 , while a rotatable stand  30  is attached to bottom wall  106  for providing a stable platform for drainage device. 
   With reference to collection chamber  14 , partitions  116  and  118  divide collection chamber  14  into compartments  14   a ,  14   b  and  14   c , to facilitate periodic monitoring of the level of liquid collected from a patient&#39;s cavity. As shown by arrows  128 ,  130  and  132  in  FIG. 5 , vacuum applied to drainage device  10  forces blood and other liquid  134  from the patient&#39;s chest cavity into compartment  14   a  through collection port  26  via patient tubing  32 . When compartment  14   a  is filled to capacity, the liquid  134  will overflow through port  34  and into compartment  14   b  until that compartment is filled. Once compartment  14   b  is filled to capacity, any additional liquid  134  will overflow through port  36  and drop into compartment  14   c . The present invention contemplates the use of appropriate indicia (not shown) marked along front wall  108  for each compartment  14   a ,  14   b  and  14   c  for providing a clear visual indication of the level of liquid being deposited in each respective compartment. 
   As best illustrated in  FIGS. 5 and 6 , once fluid from a patient&#39;s cavity is deposited inside collection chamber  14 , gases are evacuated through the water seal chamber  16 . Water seal chamber  16  prevents reflux of gases back to the patient by preventing the reentry of such gases into the collection chamber  14  using a buoyant valve  38  in combination with a water seal  20 . The structure and operation of the buoyant valve  38  is disclosed in U.S. Pat. No. 4,372,336 to Cornell et al., entitled “Chest Drainage Unit With Controlled Automatic Excess Negativity Relief Feature” which has been incorporated by reference in its entirety. The water seal chamber  16  comprises a compartment  136  having upper and lower portions with the upper portion housing valve  38  and the lower portion having water seal  20  disposed therein. The lower portion of compartment  136  communicates with the lower portion of the suction control chamber  18  which is separated from compartment  136  by partition  126 . As gases pass through the water seal  20  from collection chamber  14 , the gases are evacuated from drainage device  10  through vacuum regulator assembly  22  to a vacuum source (not shown). 
   As further shown, vacuum regulator assembly  22  provides a means for regulating the degree of vacuum, venting of excess positive pressure, and a pathway for evacuating gases from drainage device  10 . The basic operation of vacuum regulator assembly  22  is disclosed in U.S. Pat. No. 4,911,697 to Kerwin and is herein incorporated by reference in its entirety. Preferably, vacuum regulator assembly  22  comprises a positive pressure relief valve (not shown) for venting excess positive pressure generated inside collection chamber  14  and a vacuum port  68  for communicating with a source of vacuum. Both the positive pressure relief valve and vacuum port  68  communicate with a suction control chamber  18  that is in fluid flow communication with water seal  20 . As illustrated in  FIG. 6 , arrow  53  represents the flow of evacuated gas from the collection chamber  14  and through water seal  20 . Once the gas passes through water seal  20  it is evacuated from the suction control chamber  18  through the vacuum port  68  to the vacuum source. 
   Referring to  FIG. 7 , vacuum regulator assembly further comprises an adjustable knob  54  for controlling the degree of vacuum applied to drainage device  10 . One unique aspect of the present invention is that knob  54  has a slanted surface  70  which is formed adjacent an annular shaped skirt  61  having a knurled portion  72  with ribs  62  interposed therebetween. As further shown, vacuum regulator assembly  22  comprises a base  64  seated on top wall  104  and a foundation  66  formed adjacent base  64  which seats knob  54  in rotatable engagement. Slanted surface  70  includes vacuum setting indicia  60 , for example numerals, which gives the user a visual indication as to the degree of vacuum being applied to drainage device  10 . As shall be appreciated by one of skill in the art, the configuration of slanted surface  70  permits a user to view vacuum setting indicia  60  from the top and all sides of drainage device  10  regardless of whether the device  10  is placed on the floor, alongside a patient, or suspended from a pole. A marking arrow  58  is formed on a slanted raised portion  65  which is provided directly below skirt  61  for indicating the exact degree of vacuum being indicated by vacuum setting indicia  60 . The configuration of the slanted raised portion  65  also allows the user to view the marking arrow  58  from many directions. As further shown, a top portion  63  is provided adjacent slanted surface  70  and includes a raised indication arrow  56  which gives the user a visual indication as to the proper direction of increased vacuum when rotating knob  54 . Preferably, the user rotates knob  54  in a clockwise direction for increasing vacuum and a counter-clockwise direction for decreasing vacuum; however, in the alternative an increase in vacuum may be made by rotating knob  54  in a reverse direction. Collectively, the vacuum setting indicia  60  on slanted surface  70  in combination with the marker arrow  58  on raised portion  65  permit the user to view the actual vacuum setting from either the top ( FIG. 2 ) or the side ( FIGS. 1 ,  3  and  4 ) of drainage device  10  regardless of where device  10  is placed relative to the user. 
   Another aspect of the present invention is the provision for providing a visual indication of vacuum being applied to drainage device  10  that is visible to the user from a number of directions. Referring to  FIGS. 8 ,  11  and  12 , vacuum indicator assembly  24  comprises a raised base  74  defining a tubular-shaped extension member  79  forming a recess  85  at the free end of member  79  in communication with an internal chamber  88 . Recess  85  comprises a slanted surface  96  which includes a vacuum symbol  84  marked thereon for indicating the presence of vacuum inside drainage device  10  and a hole  86  for establishing fluid flow communication between vacuum indicator assembly  24  and collection chamber  14 . Because slanted surface  96  is formed at approximately a 45 degree angle relative to top wall  104 , the user may easily view vacuum symbol from either the front, top or side of drainage device  10  when vacuum is present in collection chamber  14  as shall be explained in greater detail below. Base  74  further defines an insert portion  98  formed adjacent extension member  79  which is sized and shaped to engage an aperture  71  ( FIG. 5 ) having a peripheral edge  95  formed through top wall  104  of casing  12 . As further illustrated in  FIG. 5 , aperture  71  communicates with one end of a U-shaped passageway  40  through chamber  88 , while the other end of passageway  40  communicates with collection chamber  14  through a flow chamber  42  which houses valve  38 . 
   Referring to  FIGS. 8 and 10 , vacuum indicator assembly  24  further comprises a semi-transparent, collapsible thimble  76  which is sized and shaped to snuggly fit over extension member  79  and a protective cover  78  for encasing the thimble  76  and base  74 . As shown specifically in  FIG. 10 , thimble  76  comprises a body  82  defining a slanted surface  83  at one end and a flange  94  at the other end thereof. When thimble  76  is properly engaged over base  74 , a pocket  87  is formed between thimble  76  and recess  85  which is in fluid flow communication with collection chamber  14  through hole  86 . Thimble  76  further defines a section  94  having increased thickness relative to the remainder of thimble  76 . When the vacuum indicator assembly  24  is properly assembled, the peripheral edge  95  of aperture  71  abuts section  94  of thimble  76  against base  74  such that a fluid tight seal is established. 
   Referring to  FIGS. 2 ,  9  and  12 , protective cover  78  has a beveled surface  80  which is shaped substantially similar in configuration to thimble  76 . Cover  78  further includes an alignment member  100  defining an opening  102  which engages a raised extension  103  extending outwardly from top wall  104 . When vacuum indicator assembly  24  is properly aligned by alignment member  100 , vacuum symbol  84  is viewable by the user from either the top or sides of drainage device  10 . Preferably, cover  78  is made of polystyrene, the thimble of silicone, and the base of polypropylene, although any suitable medical grade material is felt to fall within the scope of the present invention. 
   In operation, vacuum indicator assembly  24  exposes vacuum symbol  84  to view whenever vacuum is present within the collection chamber  14 . Because of the free communication between the pocket  87  of vacuum indicator assembly  24  and the collection chamber  14 , the same degree of vacuum present within the collection chamber  14  will also be present inside pocket  87 . Accordingly, the vacuum present within pocket  87  causes the portion of thimble  76  covering recess  85  to deflate and collapse over recess  85 , thereby exposing vacuum symbol  84  to view by the user through the semi-transparent material of thimble  76 . Conversely, when no vacuum is present within the collection chamber  14  thimble  76  is caused to inflate and mask vacuum symbol  84  from view. 
   Referring to  FIG. 3 , rear wall  100  defines an aperture  47  in fluid flow communication with suction control chamber  18 . According to one aspect of the present invention, a rotatable fill spout  48  covers aperture  47  and provides a means for filling the water seal chamber  16  with water for forming water seal  20 . Another aspect of the present invention is the provision for a water seal access port  50  ( FIG. 3 ) having a mechanical one way valve (not shown) adapted to engage a needless syringe (not shown). In operation, the user engages the water seal access port  29  with the syringe in order to remove excess water seal  30  or add more water seal  30  to the water seal chamber  16 . 
   It should be understood from the foregoing that, while particular embodiments of the invention have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the present invention. Therefore, it is not intended that the invention be limited by the specification; instead, the scope of the present invention is intended to be limited only by the appended claims.