Abstract:
An improved connector having limited durability for a disposable chest compression vest is quiet and cost effective. Among other advantages, the connector is heat sterilizable and flat so that the vest can be efficiently packaged and stacked, which is particularly beneficial for use in a hospital.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to chest compression devices and in particular to a high-frequency chest wall oscillator device. 
     Manual percussion techniques of chest physiotherapy have been used for treatment of a variety of diseases in order to remove the excess mucous that collects in the lungs. A non-exhaustive list of such diseases includes cystic fibrosis, emphysema, asthma and chronic bronchitis, to remove the excess mucous that collects in the lungs. To alleviate dependency on a care giver to provide this therapy, chest compression devices have been developed to produce high frequency chest wall oscillation (HFCWO), the most successful method of airway clearance. 
     The device most widely used to produce HFCWO is THE VEST™ airway clearance system by Advanced Respiratory, Inc. (f/k/a American Biosystems, Inc.), the assignee of the present application. A description of the pneumatically driven system is found in the Van Brunt et al. Patent, U.S. Pat. No. 6,036,662, which is assigned to Advanced Respiratory, Inc. Additional information regarding HFCWO and THE VEST™ system is found on the Internet at www.thevest.com. Other pneumatic chest compression devices have been described by Warwick in U.S. Pat. No. 4,838,263 and by Hansen in U.S. Pat. Nos. 5,543,081; 6,254,556 and 6,547,749. 
     Pneumatically-driven HFCWO produces substantial transient increases in the air flow velocity combined with a small displacement of the chest cavity volume. This action, in turn, produces a cough-like shear force and a reduction in mucous viscosity which results in an outward motion of the mucous. 
     Previous non-disposable vests were designed for one person to use multiple times over many years. The durable material that is used makes the vest too expensive to be utilized for short-term use. For hospital use, as an example, generally the patient only uses the vest during one hospital visit. The vest can not be used by multiple patients, because mucous may be expelled onto the vest by each patient, and previous vests could not be sterilized between uses. 
     Prior art disposable vests are attached to hoses through a connector that presents several problems. The connectors are large and bulky, which prevents efficient packaging and stacking of the vests. The connectors can not be heat sterilized and interfere with x-ray imaging. In addition, the connectors attach to the hose such that air pulses from the hose are forced into and bounce off of the wall of an inflatable air bladder that is part of the vest. This effect can be heard by the patient and those in the vicinity of the patient. Therefore, there is a need for a more cost-effective and quieter vest designed for short-term single-patient use. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is a connector for connection between an inflatable air bladder and a hose of a chest compression system. The connector is made of a thermoplastic elastomer that provides limited durability to the connector. A slot is formed in the thermoplastic elastomer to form an airtight seal between the air bladder and the hose. The slot is comprised of a slit with holes at its ends which allow for easy insertion of the hose into the slot. Tabs form at the intersection of the slit and the holes, but no air leakage occurs around the holes, because the holes have a diameter that allow the tabs to recede when the slot is stretched open for insertion by the hose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a patient undergoing HFCWO using a vest of the present invention. 
         FIG. 2   a  is a view of the outside surface of the vest prior to use. 
         FIG. 2   b  is a view of the inside surface of the vest. 
         FIG. 3  is a front, cutaway view of the vest showing the hoses attached to the vest. 
         FIG. 4   a  is a front view of the connector. 
         FIG. 4   b  is a perspective view of the connector. 
         FIG. 5  is a cross section at  5  of  FIG. 3  of the hoses inserted into the connector. 
         FIG. 6  is a cross section at  6  of  FIG. 3  of the hoses inserted into the connector. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows patient P undergoing HFCWO using a system  10  with a vest  12  of the present invention. System  10  includes vest  12 , hoses  14  and air pulse generator  16 . Vest  12  fits around the chest of patient P. Hoses  14  connect at one end to vest  12  and at the other end to air pulse generator  16 . 
     During treatment, air pulse generator  16  generates oscillatory air pulses which travel to vest  12  through hoses  14 . The result is oscillatory chest compressions delivered to the chest of patient P for clearing mucus from the lungs of patient P. 
       FIG. 2   a  shows the outside of vest  12  prior to use. Vest  12  includes belt  18 , cover  20  with indicia  22 , attachment  24  and hose tie  26 . Cover  20  spans across the width of belt  18  and is sewn along the top and bottom edges. Cover  20  covers the area where hoses  14  connect to vest  12 , which will later be discussed in detail. Indicia  22 , shown as a dashed line on cover  20 , indicates that cover  20  should be torn or cut prior to use. Attachment  24  is mounted at one end of belt  18  near cover  20 . Hose tie  26  is attached on the other side of cover  20  to belt  18 . 
       FIG. 2   b  shows the inside of vest  12 , which is inverted vertically relative to vest  12  shown in  FIG. 2   a . Vest  12  includes belt  18 , air bladder  28  (shaded region) and attachment  30 . Air bladder  28  is attached at one end of belt  18  and preferably covers an area that is essentially on the direct opposite side of belt  18  from attachment  24  and cover  20 . Attachment  30  is preferably near the opposite end of belt  18  from air bladder  28 . 
     Prior to fitting vest  12  on patient P, cover  20  is checked to verify that cover  20  is intact. This provides indication that vest  12  is unused and has not been tampered with. If cover  20  is torn or cut, vest  12  should not be used. If cover  20  is intact, then it may be torn or cut as indicated by indicia  22 . Indicia  22  can be any indicator showing that cover  20  must be torn or cut prior to use. 
     To fit vest  12  on patient P, belt  18  is wrapped around patient P such that air bladder  28  is on the inside of vest  12  and over the chest of patient P. Attachment  30  is then connected to attachment  24  to secure vest  12  in place. Preferably, attachments  24  and  30  are mates for a hook-and-loop type attachment, but any type of attachment may be used. Either or both of attachment  24  and  30  should be of a relatively large size so the circumference of vest  12  is adjustable to fit many sizes of people. 
       FIG. 3  shows hoses  14  connected to vest  12 . To simplify the drawing, cover  20  is not shown but would be torn or cut at this point. Vest  12  and hoses  14  are shown cutaway. Vest  12  includes belt  18 , attachment  24 , hose tie  26  and connector  32 . 
     In operation, hoses  14  are connected to vest  12  via connector  32 . Hoses  14  are inserted through slots in connector  32  (discussed in detail below) that are in communication with air bladder  28  such that hoses  14  lay along belt  18  and are secured to belt  18  by hose tie  26 . The openings of hoses  14  point in a direction essentially parallel to belt  18 , the chest of patient P and/or connector  32 . Hose tie  26  positions hoses  14  parallel to the same plane. Hose tie  26  is preferably comprised of a loop of hook-and-loop type material, but any type of attachment that secures hoses  14  to belt  18  may be used. 
     Having hoses  14  angled in this manner allows system  10  to be quieter during treatment compared to prior art disposable vests. Prior art disposable vests use connectors that force air into air bladder  28  at an angle that is essentially perpendicular to belt  18 . The oscillatory air pulses that are forced into air bladder  28  bounce off the wall of air bladder  28 , which creates noise. With the present invention having hoses  14  angled as described above, the air pulses no longer bounce off the wall of air bladder  28  resulting in a quieter system. 
       FIG. 4   a  shows connector  32 . Connector  32  includes slots  34  with slits  36  having edges  36   a  and  36   b , holes  38  and tabs  40 ; and finger grips  42 .  FIG. 4   b  is a perspective view of connector  32  showing slot  34  and finger grips  42 . 
     Connector  32  is shown in its preferred embodiment having two slots  34 . However, connector  32  may have only one slot  34  or more than two depending on the number of hoses  14  which need to be connected to vest  12 . Each slot  34  has slit  36  with flaps  36   a  and  36   b  at either side. Holes  38  are at the ends of slit  36  such that slot  34  is a continuous opening between slit  36  and holes  38 . Tabs  40  form where flaps  36   a  and  36   b  meet with holes  38 . Finger grips  42  are offset from the center of slots  34  and protrude perpendicularly from connector  32 . 
     The openings formed by slots  34  allow hoses  14  to communicate with air bladder  28 . To connect hose  14  to vest  12 , patient P or someone else grasps finger grip  42  to stretch open slot  34  and inserts hose  14 . Finger grip  42  is not required for this invention but makes it easier to insert hose  14  into slot  34 . The dimensions and shape of finger grips  42  are not critical as long as they can be grasped. Finger grips  42  are preferably a protrusion of the same material as connector  32  and have a height of about 0.44 in and a diameter of about 0.13 in. 
       FIGS. 5 and 6  are cross sections  5  and  6  of hose  14  inserted through slots  34 , as shown in  FIG. 3 .  FIGS. 5 and 6  include hoses  14 , air bladder  28 , connector  32  and flaps  36   a  and  36   b . When hose  14  is inserted through slot  34 , flap  36   b  stretches over hose  14  and is exposed to the outside. Flap  36   a  stretches under hose  14  and is substantially inside air bladder  28 . Connector  32  is substantially part the wall of the air bladder by forming an airtight seal around hose  14 . 
     Holes  38  function to make insertion of hose  14  easier and decreases stress on the material forming the seal. The dimensions of holes  38  relative to the dimensions of slit  36  and hose  14  are a factor in forming an airtight seal. The diameter of holes  38  are such that when hose  14  is inserted into slot  34 , slot  34  is stretched to a point where tabs  40  recede. When tabs  40  recede there is no air leakage around slot  34 . In the preferred embodiment, a hose having a 1.25 in. outside diameter is inserted. The distance between the centers of holes  38  is about 1.225 in., but the length of slit  36  may vary by up to approximately 5%. The width of the gap between flaps  36   a  and  36   b  is about 0.03 in. but can vary significantly. The diameter of holes  38  is about 0.187 in. 
     To this end, connector  32  must be made of an elastic sheet material. Latex, however, is not a preferred material for the present invention. Preferably, connector  32  is made from a thermoplastic elastomer, an example of which is 0.060 in. Versaflex CL30 Shore A 29D. 
     The durometer hardness rating of the material forming connector  32  is also a factor in obtaining an acceptable connector. The preferred material has limited durability, meaning it is durable enough for a single patient to use in the short-term, but since it is inexpensive enough for a cost-effective disposable vest, it will not last through multiple uses over the long-term. The preferred material above has a durometer hardness rating of about 29 on the Shore A scale but can range from about 20 to about 40. 
     The hardness and thickness of the material forming connector  32  have an inverse relationship, and the dimensions of holes  38  depend on this relationship. If the material is too soft, slot  34  lacks enough tension to form an airtight seal. Increasing the thickness of the material, however, will increase the amount of tension. Likewise, if the material is too hard, slot  34  will not conform to the proper shape change needed to create the seal, but decreasing the thickness of the material allows it to conform to the proper shape. Holes  38  allow more tolerance in varying the hardness and thickness of the material. As discussed above, the dimensions of holes  38  are a factor, but change, for each combination of hardness and thickness of the material. The dimensions are a factor because if holes  38  are too small, stresses and tears occur around slot  34 . If holes  38  are too large, slot  34  leaks. 
     The length of slit  36  and width of the gap between flaps  36   a  and  36   b  can vary somewhat for each combination of hardness and thickness. In fact, the gap can be as small as a cut with a knife blade or large enough that slot  34  more closely resembles an oval. However, an actual oval shape is not preferred, because there is a tendency for gaps to form and leakage to occur where tabs  40  would otherwise be located. 
     For ease in hospital use, the material should also be able to withstand heat sterilization and not interfere with imaging on x-ray films. Consequently, vest  12  can be sterilized inexpensively, and patient P can wear vest  12  even while being x-rayed. Prior art vests utilized hard plastic connectors that showed through on x-ray films and would melt if heat sterilized. The preferred thermoplastic elastomer above possesses these advantageous qualities. 
     Lastly, because connector  32  is flat, it makes vest  12  much more cost effective for packaging and storing. Vests  12  can be packaged flat and stacked together. The connectors of prior art disposable vests are relatively large and bulky. Prior art vests cannot be packaged and stacked flat because of the connector. Therefore, a disposable vest having a connector of the present invention overcomes the disadvantages of the prior art connectors to make a quieter and more cost effective chest compression system. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.