Abstract:
A pneumatic chest compression vest is disclosed for the purposes of clearing the lungs of mucus and producing quality sputum samples for analysis. The vest is comprised of a belt and a front panel which has an air bladder that applies a compressive force to the region of the chest that encompasses the lungs mounted on its inner surface. The belt extends around a patient to hold the vest in the correct position during treatment.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This is a continuation of application Ser. No. 09/387,339, filed on Aug. 31, 1999, now U.S. Pat. No. 6,471,663 entitled “Chest Compression Vest with Connecting Belt. 
    
    
     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 a variety of diseases such as cystic fibrosis, emphysema, asthma, and chronic bronchitis, to remove the excess mucus that collects in the lungs. To bypass 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. In addition, these devices can be utilized for induction of high quality sputum samples for screening and diagnosing a number of pulmonary disorders such as lung cancer, asthma, chronic obstructive pulmonary disease (COPD), tuberculosis,  Pneumocystis carinii pneumonia  (PCP), inflammation, and infection. 
     The device most widely used to produce HFCWO is the ABI Vest Airway Clearance System by American Biosystems, the assignee of the present application. A description of the pneumatically driven system can be found in the Van Brunt et al. patent, U.S. Pat. No. 5,769,797, which is assigned to American Biosystems, Inc. Another pneumatic chest compression device has been described by Warwick et al., U.S. Pat. No. 4,838,263. 
     Pneumatically driven HFCWO produces substantial transient increases in the airflow velocity with a small displacement of the chest cavity volume. This action produces a cough-like shear force and reduction in mucus viscosity that results in an upward motion of the mucus. 
     A shortcoming of the design of the vests used by these devices is that the compressions are not concentrated on the region of the chest which directly surrounds the lungs. An inflatable air bladder that provides the compressive force extends all the way around the patient including the back. The bladder has a rather large volume which renders it inadequate to create the magnitude of force necessary on regions encompassing the lungs to clear the lungs of mucus or induce deep sputum that, for example, provides optimal samples for lung cancer screening. In addition, since the vests close in the front, the air bladder is not continuous over the chest. The air bladder&#39;s design does not allow it to reach to the highest lobes of the lung, and it extends too low resulting in compression on the stomach, a particular problem for short adults and children. This results in inefficient and insufficient mucus induction and mobilization. Thus, there remains a need to design a vest which focuses the force in the proper regions to give optimal results. 
     Prior art vests, when fastened to the patient and not inflated, take on the shape of the torso. When inflated they bow outward. The outer material is not rigid enough to maintain its shape, and so the vest takes on a more circular shape. The outward force, which causes the bowing, increases the volume of the air bladder, but it is more desirable to have the increase in volume result from a change in the shape of the chest. Therefore, a vest which maintained its shape would be more efficient, because the outward force that causes the vest to change shape would not cancel out the inward compressive force. 
     The previous vests were designed for one person to use multiple times. The durable material that is used makes the vest too expensive to be utilized for a single use and cannot be easily and cleanly burned for disposal. For analysis of sputum samples, though, generally the patient only needs the vest one time. The vests, however, cannot be used by multiple patients, because mucus is expelled onto the vest by each patient, and the vests cannot be sterilized between uses. Therefore, there is also a need for a vest which is cost effective for single-use. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is a pneumatic chest compression vest which loosens and helps remove mucus from a person&#39;s lungs or induces production of sputum samples for further diagnostic analysis. The vest is designed to focus the compressive force on the region of the chest which encompasses the lungs. 
     The vest includes a front panel having a central bib portion and side portions. An air bladder is mounted to the inner surface of the front panel. Air ports and removable air couplings on the front panel are in communication with the air bladder. When inflated, the air bladder applies a compressive force focused on the region of the chest which encases the lungs. 
     The vest also includes a belt that connects to the front panel and extends around the person and across the outer surface of the front panel. The belt contains a plurality of longitudinally spaced holes which align with the air ports on the front panel. The air couplings extend through the holes in the belt and the air ports to secure the vest and connect the air bladder to a source of oscillating pneumatic pressure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a person wearing a pneumatic chest compression vest. 
     FIG. 2 is a front view of a pneumatic chest compression vest. 
     FIG. 3 is a back view of a pneumatic chest compression vest. 
     FIG. 4 is a side view of an air coupling connected to a hose. 
     FIG. 5 is a top view of a suspender. 
     FIG. 6 shows where a person&#39;s lungs are located relative to a pneumatic chest compression vest. 
     FIG. 7 is a graph illustrating the enhanced performance of a pneumatic chest compression vest in the preferred position. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows pneumatic chest compression vest  10  of the present invention fitted onto patient P. Pneumatic chest compression vest  10  is shown with front panel  12 , belt  14  with belt holes  16 , air couplings  18 , suspenders  20 , hoses  22 , and pneumatic pressure generator  24 . Front panel  12  of pneumatic chest compression vest  10  covers from approximately the bottom of the patient&#39;s rib cage to near the patient&#39;s collar bone and extends over the front of the patient&#39;s chest to under the patient&#39;s arms. Belt  14 , which is attached to one side of front panel  12 , wraps around the patient&#39;s back and across front panel  12 . Pneumatic chest compression vest  10  is secured by aligning belt holes  16  with air ports (not shown) on front panel  12  so that air couplings  18  can insert through belt holes  16  and the air ports. Suspenders  20  are also attached to secure pneumatic chest compression vest  10  in place. One end of hoses  22  attaches to air couplings  18  and the other end attaches to pneumatic pressure generator  24 . Pneumatic pressure generator  24  provides the oscillating pressure to vest  10  to apply compressive force to the patient&#39;s chest. Pneumatic chest compression vest  10  and its operation will be described in more detail in subsequent figures. 
     FIG. 2 is a front view of pneumatic chest compression vest  10  laid flat. Front panel  12  is comprised of central bib portion  12   a,  side portions  12   b  and  12   c,  tab  34 , tab seams  36 , air ports  38 , and liner seam  40 . Belt  14 , which attaches to front panel  12  at belt seam  30 , contains belt holes  16  with slits  32 . 
     Pneumatic chest compression vest  10  wraps around the torso of patient P. Belt  14  of pneumatic chest compression vest  10  extends around the back of patient P and across the outer surface of front panel  12 . Belt  14  contains longitudinally positioned belt holes  16  each of which includes a slit  32 . Tab  34  is welded onto front panel  12  at tab seams  36  and inserts into one of the belt holes  16 . 
     Pneumatic chest compression vest  10  is secured in place by overlapping belt holes  16  with air ports  38  on front panel  12 . The distance between air ports  38  corresponds to a multiple of the distance between each belt hole  16 . In a preferred embodiment, the diameter of belt holes  16  and air ports  38  is about 1.4 inches with belt holes  16  centered about 2 inches apart, and air ports  38  are centered about 6 inches apart. Tab  34  is welded to front panel  12  at tab seams  36  so that it aligns with air ports  38  on front panel  12  in such a way that as belt  14  wraps around patient P and extends across the outer surface of front panel  12 , tab  34  can insert into a belt hole  16 . When tab  34  is inserted into a belt hole  16 , corresponding belt holes  16  will align with air ports  38 . Once aligned, air couplings  18  can easily be snapped into belt holes  16  and air ports  38  (see FIG.  1 ). Depending on the circumference of the patient&#39;s torso, different belt holes  16  will align with tab  34  and air ports  38 . This allows adjustment of pneumatic chest compression vest  10  so that it fits securely around patient P. 
     Slits  32  are preferably about 0.2 inch long. Slits  32  allow ease of insertion of suspenders  20  into belt holes  16  (see FIG.  1 ). 
     Liner seam  40  extends along the perimeter of front panel  12  encompassing central bib portion  12   a,  which has a preferred height of about 11.75 inches but can be from about 9.0 to about 13.0 inches, and side portions  12   b  and  12   c,  which have a preferred height of about 7.75 inches but can be from about 6.0 to about 9.0 inches. 
     FIG. 3 is a back view of pneumatic chest compression vest  10  laid flat. Front panel  12  includes central bib portion  12   a,  side portions  12   b  and  12   c,  air ports  38  (in phantom), and liner seam  40 . A liner  50  is shown welded to the inner surface of front panel  12  along liner seam  40 . Belt  14 , belt holes  16  with slits  32 , belt seam  30 , and tab  34  (in phantom) are shown and were described in FIG.  2 . 
     Liner  50  is preferably made of an elastic material such as 4 mil polyethylene, and the remaining parts, except air couplings  18 , are made of an inelastic material such as 8 mil polycarbonate. These materials are relatively inexpensive and can be easily incinerated, producing no toxic emissions and little particulate matter for disposal. Liner  50  mounted onto front panel  12  defines an air bladder which is preferably about 21 inches wide. 
     In operation, the air bladder is inflated via air ports  38  against the chest of patient P to apply a compressive force to the patient&#39;s lungs. Side portions  12   b  and  12   c  allow the air bladder to extend under the arms of patient P. Thus, the air bladder also compresses the sides of the torso which cover the patient&#39;s lungs. Since the air bladder does not extend along belt  14 , the compressive force is focused on the proper region for optimal treatment. The combination of a generally rigid outer surface and flexible bladder prevents the vest from taking on a circular shape when the air bladder is inflated. Instead, inflating the air bladder forces the chest to change shape so that most of the motion during compression is inward, and the outward force is minimized. This increases the efficiency of the system. The volume of the air bladder is also reduced over the prior art vests, which makes the system more efficient in terms of applying the same volume of air over a smaller surface area so that the magnitude of force necessary for deep sputum induction is achieved. 
     Pneumatic chest compression vest  10  is suitable for typical pressure requirements of about 0.5 to about 1.0 P.S.I., and can operate for about 30 to about 45 minutes during an oscillatory chest compression treatment. It may last longer for other less stringent applications. 
     FIG. 4 shows a side view of air coupling  18  connected to hose  22 . Air coupling  18  includes head  18   a,  neck  18   b,  and body  18   c  (shown partially in phantom). A portion of hose  22  is shown partially enclosing body  18   c  of air coupling  18 . 
     In a preferred embodiment, air coupling  18  is made of aluminum with a height of about 3.25 inches. The height of head  18   a  is about 0.85 inches, neck  18   b  is about 0.75 inches, and body  18   c  is about 1.65 inches and is removably attached to neck  18   b.  Also, hose  22  is angled about 90° at the end that connects to air coupling  18 . 
     Head  18   a  is beveled with the diameter increasing from about 1.30 inches to about 1.40 inches. The inside diameter of head  18   a  is about 1.15 inches. Neck  18   b  has a diameter of about 1.36 inches. Body  18   c  has a diameter of about 1.50 inches with an inside diameter of about 1.20 inches. The inside diameter of air coupling  18  increases from head  18   a  to body  18   c.    
     The operation of air coupling  18  is discussed in reference to parts of pneumatic chest compression vest  10  that are not shown. Head  18   a  snaps through belt holes  16  and air ports  38  into the air bladder. Neck  18   b  remains within front panel  12  and belt  14  to secure pneumatic chest compression vest  10  around patient P. Hose  22  connects to and partially overlaps body  18   c,  which is not connected to neck  18   b  at this point. Body  18   c,  when connected to neck  18   b,  remains on the external side of pneumatic chest compression vest  10 . Thus, air coupling  18  has dual functions—to secure pneumatic chest compression vest  10  and provide a coupling to attach hose  22 . With hose  22  essentially hanging parallel to front panel  12 , hose  22  hangs in a manner which keeps air coupling  18  from pulling outward on pneumatic chest compression vest  10 . This type of system reduces the parts needed to operate the vest, which makes it less expensive to manufacture and, therefore, ideal for a disposable vest system. 
     FIG. 5 shows suspender  20  laid flat. Suspender  20  is comprised of strap  20   a  and serrated ends  20   b  which include serrations  20   c.    
     In a preferred embodiment, the length of suspender  20  is about 35.0 inches. Serrated ends  20   b  are about 7 inches long, and each includes about 6 approximately 1 inch long serrations  20   c.  Strap  20   a  has a width of about 1.1 inches. Serrations  20   c  extend out to about 1.6 inches. 
     In operation, suspenders  20  extend from the front to the back of pneumatic chest compression vest  10  and insert into two of the belt holes  16  on the front and another pair of belt holes  16  in the back. Serrations  20   c  allow suspenders  20  to be adjusted to the proper length for a secure fit. In a preferred embodiment, suspenders  20  are crossed in front of patient P to minimize movement or slippage of pneumatic chest compression vest  10  during treatment (see FIG.  1 ). 
     FIG. 6 illustrates how pneumatic chest compression vest  10  is positioned with respect to the patient&#39;s lungs and skeletal structure. An outline of front panel  12  with top edge  60  and bottom edge  62  of pneumatic chest compression vest  10  indicates the region of the patient&#39;s chest that is covered. 
     In operation, front panel  12  preferably covers the region of the torso which encases the lungs of patient P. Top edge  60  is positioned near the patient&#39;s collar bone, and bottom edge  62  is positioned near the bottom of the patient&#39;s rib cage. This provides a focused compressive force on the lungs with the necessary magnitude to induce deep sputum. Compression on the stomach is minimized, and top edge  60  reaches up to the upper lobes of the lungs to facilitate mucus removal in the upper lobes. Thus, the improved design increases the efficiency of the system to obtain sufficient sputum induction and mucus mobilization. 
     FIG. 7 shows the results of a comparison done between the present invention (new vest), the present invention without the bib section of central bib portion  12   a  (new vest w/o bib), the present invention positioned backwards (new vest backwards), and a prior art vest (old vest). FIGS. 2 and 3 provide a good view of the bib section of central bib portion  12   a.  The bib section is the part of front panel  12  that compresses the upper lobes of the lungs. Peak expiratory volume (peak volume) was measured on a single subject with each variation over an oscillatory frequency range between 5 and 20 Hertz. The subject was fitted with a vest and given a mouthpiece with a hose attached to a volume chamber. The volume chamber was equipped with a sensor that measured changes in oscillatory volume. Expiratory volumes were measured with each vest variation tested at 5, 10, 15, and 20 Hertz. The graph illustrates that the present invention in the preferred position (with the front panel over the patient&#39;s chest and the bib portion extending to about the collar bone) produces the highest peak volume of airflow. The high peak volume of airflow corresponds to an increased force asserted on the mucus which results in increased mobilization. This data supports the conclusion that the new vest is superior over prior art. 
     Pneumatic chest compression vest  10  is designed more efficiently to provide effective sputum induction for diagnostic evaluation and mucus mobilization for therapeutic lung clearance. The compressions are focused on all lobes of the patient&#39;s lungs with a force that induces deep sputum production and facilitates better lung clearance. The combination of a rigid outer surface and flexible bladder results in more efficiency in that outward forces that change the shape of the vest and cancel inward compressive forces on the chest are minimized. Pneumatic chest compression vest  10  can be composed of materials that satisfy this need and are also relatively inexpensive, and make the vest easy and safe to dispose of. The resulting vest is efficient and cost-effective for single-use. 
     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.