Abstract:
A pneumostoma management device for maintaining the patency of a pneumostoma while controlling the flow of gases and discharge through the pneumostoma. The pneumostoma management device includes a bulb connected to a tube which enters the pneumostoma. A flow control device regulates air flow in and out of the pneumostoma via the tube. A hydrophobic filter traps discharge in the bulb while allowing gases to escape.

Description:
CLAIM TO PRIORITY 
     This application claims priority to U.S. Provisional Patent Application No. 61/029,836 filed Feb. 19, 2008 entitled “PNEUMOSTOMA MANAGEMENT DEVICE AND METHOD FOR TREATMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE” which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     In the United States alone, approximately 14 million people suffer from some form of chronic obstructive pulmonary disease. However an additional ten million adults have evidence of impaired lung function indicating that COPD may be significantly underdiagnosed. The cost of COPD to the nation in 2002 was estimated to be $32.1 billion. Medicare expenses for COPD beneficiaries were nearly 2.5 times that of the expenditures for all other patients. Direct medical services accounted for $18.0 billion, and indirect cost of morbidity and premature mortality was $14.1 billion ( FIG. 11 ). COPD is the fourth leading cause of death in the U.S. and is projected to be the third leading cause of death for both males and females by the year 2020. 
     Chronic Obstructive Pulmonary Disease (COPD) is a progressive disease of the airways that is characterized by a gradual loss of lung function. In the United States, the term COPD includes chronic bronchitis, chronic obstructive bronchitis, and emphysema, or combinations of these conditions. In emphysema the alveoli walls of the lung tissue are progressively weakened and lose their elastic recoil. The breakdown of lung tissue causes progressive loss of elastic recoil and the loss of radial support of the airways which traps residual air in the lung. This increases the work of exhaling and leads to hyperinflation of the lung. When the lungs become hyperinflated, forced expiration cannot reduce the residual volume of the lungs because the force exerted to empty the lungs collapses the small airways and blocks air from being exhaled. As the disease progresses, the inspiratory capacity and air exchange surface area of the lungs is reduced until air exchange becomes seriously impaired and the individual can only take short shallow labored breaths (dyspnea). 
     The symptoms of COPD can range from the chronic cough and sputum production of chronic bronchitis to the severe disabling shortness of breath of emphysema. In some individuals, chronic cough and sputum production are the first signs that they are at risk for developing the airflow obstruction and shortness of breath characteristic of COPD. With continued exposure to cigarettes or noxious particles, the disease progresses and individuals with COPD increasingly lose their ability to breathe. Acute infections or certain weather conditions may temporarily worsen symptoms (exacerbations), occasionally where hospitalization may be required. In others, shortness of breath may be the first indication of the disease. The diagnosis of COPD is confirmed by the presence of airway obstruction on testing with spirometry. Ultimately, severe emphysema may lead to severe dyspnea, severe limitation of daily activities, illness and death. 
     There is no cure for COPD or pulmonary emphysema, only various treatments, for ameliorating the symptoms. The goal of current treatments is to help people live with the disease more comfortably and to prevent the progression of the disease. The current options include: self-care (e.g., quitting smoking), medications (such as bronchodilators which do not address emphysema physiology), long-term oxygen therapy, and surgery (lung transplantation and lung volume reduction surgery). Lung volume reduction surgery is an invasive procedure primarily for patients who have a localized (heterogeneous) version of emphysema; in which, the most diseased area of the lung is surgically removed to allow the remaining tissue to work more efficiently. Patients with diffuse emphysema cannot be treated with LVRS, and typically only have lung transplantation as an end-stage option. However, many patients are not candidates for such a taxing procedure. 
     A number of less-invasive surgical methods have been proposed for ameliorating the symptoms of COPD. In one approach new windows are opened inside the lung to allow air to more easily escape from the diseased tissue into the natural airways. These windows are kept open with permanently implanted stents. Other approaches attempt to seal off and shrink portions of the hyperinflated lung using chemical treatments and/or implantable plugs. However, these proposals remain significantly invasive and have unproven efficacy. None of the surgical approaches to treatment of COPD has been widely adopted. Therefore, a large unmet need remains for a medical procedure that can sufficiently alleviate the debilitating effects of COPD and emphysema. 
     SUMMARY OF THE INVENTION 
     In view of the disadvantages of the state of the art, Applicants have developed a method for treating COPD in which an artificial passageway is made through the chest wall into the lung. An anastomosis is formed between the artificial passageway and the lung by creating a pleurodesis between the visceral and parietal membranes surrounding the passageway as it enters the lung. The pleurodesis prevents air from entering the pleural cavity and causing a pneumothorax (deflation of the lung due to air pressure in the pleural cavity). The pleurodesis is stabilized by a fibrotic healing response between the membranes. The artificial passageway through the chest wall also becomes epithelialized. The result is a stable artificial aperture through the chest wall which communicates with the parenchymal tissue of the lung. 
     The artificial aperture into the lung through the chest is referred to herein as a pneumostoma. The pneumostoma provides an extra pathway that allows air to exit the lungs while bypassing the natural airways which have been impaired by COPD and emphysema. By providing this ventilation bypass, the pneumostoma allows the stale air trapped in the lung to escape from the lung. By shrinking the lung, the ventilation bypass allows more fresh air to be drawn in through the natural airway and increases the effectiveness of all of the tissues of the lung. Increasing the effectiveness of gas exchange allows for increased absorption of oxygen into the bloodstream and also increased removal of carbon dioxide. Reducing the amount of carbon dioxide retained in the lung reduces hypercapnia which also reduces dyspnea. The pneumostoma thereby achieves the advantages of lung volume reduction surgery without surgically removing a portion of the lung or sealing off a portion of the lung. 
     In accordance with an embodiment of the present invention a partially-implantable pneumostoma management device is provided which can be placed into a pneumostoma to prevent the entry of foreign substances into the lung, control air flow through the pneumostoma and collect any materials that may exit the lung. 
     In accordance with another embodiment of the present invention a pneumostoma management device is provided with a hydrophobic filter element. The pneumostoma management device includes a hydrophobic filter to prevent the entry of water into the device and pneumostoma. 
     In accordance with another embodiment of the present invention a pneumostoma management device is provided with a flow-control device. The flow-control device permits air to flow out of the pneumostoma but inhibits the flow of air into the pneumostoma. 
     In accordance with another embodiment of the present invention a pneumostoma management device is provided with an integral trap chamber. The integral trap system for collecting any liquid or particulate matter which may be emitted through the pneumostoma. 
     In accordance with another embodiment of the present invention a method for controlling entry and exit of material through a pneumostoma is provided in which the disclosed pneumostoma management device is temporarily implanted in a pneumostoma. 
     In accordance with a particular embodiment of the present invention, a pneumostoma management device is configured to be mounted on a chest of a patient to treat a lung of a patient and control the flow of liquids and gases through a pneumostoma. The pneumostoma management device includes a tube adapted to pass into the pneumostoma wherein the tube has a distal opening adapted to be positioned within the lung to allow liquids and gases to enter the tube from the lung. The pneumostoma management device also includes a bulb connected to a proximal end of the tube wherein the bulb defines a chamber. A one-way valve is positioned between the distal opening of the tube and the chamber such that liquids and gases may enter the chamber from the tube but are prevented from leaving the chamber through the one-way valve. The bulb has an external opening in which a hydrophobic filter is positioned which allows gases to escape the chamber via the external opening but prevents liquids from escaping the chamber via the external opening. The pneumostoma management device thus allows gases to pass from the lung of the patient through the pneumostoma management device and escape through the external aperture. Whereas liquids pass from the lung into the chamber where they are trapped between the one-way valve and the hydrophobic filter. 
     Thus, various devices and methods are provided for managing a pneumostoma. Other objects, features and advantages of the invention will be apparent from drawings and detailed description to follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and further features, advantages and benefits of the present invention will be apparent upon consideration of the present description taken in conjunction with the accompanying drawings. 
         FIG. 1A  shows the chest of a patient showing a pneumostoma that may be managed using the device and methods of the present invention. 
         FIG. 1B  shows a sectional view of the chest illustrating the relationship between the pneumostoma, lung and natural airways. 
         FIG. 1C  shows a detailed sectional view of a pneumostoma. 
         FIG. 2A  shows a perspective cutaway view of a pneumostoma management device according to an embodiment of the present invention. 
         FIG. 2B  shows a sectional view of a pneumostoma management device according to an embodiment of the present invention. 
         FIG. 3A  shows the chest of a patient illustrating placement of the pneumostoma management device according to an embodiment of the present invention. 
         FIG. 3B  shows a sectional view of a pneumostoma illustrating placement of the pneumostoma management device according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best modes presently contemplated for practicing various embodiments of the present invention. The description is not to be taken in a limiting sense but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be ascertained with reference to the claims. In the description of the invention that follows, like numerals or reference designators will be used to refer to like parts or elements throughout. In addition, the first digit of a reference number identifies the drawing in which the reference number first appears. 
     Pneumostoma Formation and Anatomy 
       FIG. 1A  shows the chest of a patient showing a pneumostoma that may be managed using the device and methods of the present invention. Pneumostoma  110  is shown on the front of the chest  10  over the right lung (not shown). In general one pneumostoma per lung is created however, more or less than one pneumostoma per lung may be created depending upon the needs of the patient. A pneumostoma is surgically created by forming an artificial channel through the chest wall and joining that channel with an opening through the visceral membrane of the lung into parenchymal tissue of the lung to form an anastomosis. The anastomosis is preferably joined and sealed by sealing the channel to the lung using adhesions such as a pleurodesis. Methods for forming the channel, opening, anastomosis and pleurodesis or the pneumostoma are disclosed in applicant&#39;s commonly-owned, patents and patent applications including U.S. patent application Ser. No. 10/881,408, now U.S. Pat. No. 7,682,332, issued Mar. 23, 2010, entitled “Methods and Devices to Accelerate Wound Healing in Thoracic Anastomosis Applications” and U.S. Provisional Patent Application Ser. No. 60/938,466 entitled “Variable Parietal/Visceral Pleural Coupling” which are incorporated herein by reference. 
       FIG. 1B  shows a sectional view of the chest  100  illustrating the position of the pneumostoma  110 . The parenchymal tissue of the lung is comprised principally of alveoli  134 . The alveoli  134  are the thin walled air-filled sacs in which gas exchange takes place. Air flows into the lungs through the natural airways including the trachea  136 , carina  137 , and bronchi  138 . Inside the lungs, the bronchi branch into a multiplicity of smaller vessels referred to as bronchioles (not shown). Typically, there are more than one million bronchioles in each lung. Each bronchiole connects a cluster of alveoli to the natural airways. As illustrated in  FIG. 1B , pneumostoma  110  comprises a channel  120  through the thoracic wall  106  of the chest  100  between the ribs  107 . Channel  120  opens at an aperture  126  through the skin  114  of chest  100 . The channel  120  is joined to a cavity  122  within the parenchymal tissue  132  of lung  130 . 
       FIG. 1C  shows a detailed sectional view of the pneumostoma  110 . As illustrated in  FIG. 1C , pneumostoma  110  comprises a channel  120  through the thoracic wall  106  of the chest  100  between the ribs  107 . The channel  120  is joined to cavity  122  in the parenchymal tissue  132  of lung  130 . An adhesion or pleurodesis  124  surrounds the channel  120  where it enters the lung  130 . The thoracic wall  106  is lined with the parietal membrane  108 . The surface of the lung  130  is covered with a continuous sac called the visceral membrane  138 . The parietal membrane  108  and visceral membrane  138  are often referred to collectively as the pleural membranes. Between the parietal membrane  108  and visceral membrane  138  is the pleural cavity (pleural space)  140 . The pleural cavity usually only contains a thin film of fluid that serves as a lubricant between the lungs and the chest wall. In pleurodesis  124  the pleural membranes are fused and/or adhered to one another eliminating the space between the pleural membranes in that region. 
     An important feature of the pneumostoma is the adhesion or pleurodesis  124  surrounding the channel  120  where it enters the lung  130 . The pleurodesis  124  is the localized fusion or adhesion of the parietal membrane  108  and visceral membrane  138 . The pleurodesis  124  surrounding the channel  120  prevents air from the lung  130  or channel  120  from entering the pleural cavity  140 . If air is permitted to enter pleural cavity  140 , a pneumothorax would result and the lung would collapse. One method for creating pleurodesis between the visceral pleura of the lung and the inner wall of the thoracic cavity uses chemical methods, including irritants such as Doxycycline and/or Bleomycin, surgical methods, including pleurectomy or thorascopic talc pleurodesis, or radiotherapy methods, including radioactive gold or external radiation. All of these methods inflames and fuse the pleural membranes. Alternatively adhesion can be created between the pleural membranes using biocompatible glues. A range of biocompatible glues are available that may be used on the lung, including light-activatable glues, fibrin glues, and two part polymerizing glues. 
     The pneumostoma  110  provides an extra pathway for exhaled air to exit the lung  130  without passing through the major natural airways such as the bronchi  138  and trachea  136 . Collateral ventilation is the term given to leakage of air through the connective tissue between the alveoli  134 . This air typically becomes trapped in the lung and contributes to hyperinflation. Collateral ventilation is particularly prevalent in an emphysemous lung because of the deterioration of lung tissue caused by COPD. In lungs that have been damaged by COPD and emphysema the resistance to flow in collateral channels (not shown) of the parenchymal tissue  132  is reduced allowing collateral ventilation to increase. By providing pneumostoma  110 , air from alveoli  134  of parenchymal tissue  132  that passes into collateral pathways of lung  130  is collected in cavity  122  of pneumostoma  110 . Pneumostoma  110  thus makes use of collateral ventilation to collect air in cavity  122  of pneumostoma  110  and vent the air outside the body while bypassing the natural airways which have been impaired by COPD and emphysema. 
     By providing this ventilation bypass, the pneumostoma allows the stale air trapped in the parenchymal tissue  132  to escape from the lung  130  and reduces the residual volume and intra-thoracic pressure. The lower intra-thoracic pressure reduces the dynamic collapse of airways during exhalation. By allowing the airways to remain patent during exhalation, labored breathing (dyspnea) and residual volume (hyperinflation) are both reduced. The pneumostoma not only provides an extra pathway that allows air to exit the lungs but also allows more fresh air to be drawn in through the natural airway and increases the effectiveness of all of the tissues of the lung improving gas exchange. The pneumostoma thus achieves many of the advantages sought by lung volume reduction surgery without surgically removing a portion of the lung or sealing off a portion of the lung. 
     Applicants have found that a pneumostoma management device in accordance with embodiments of the present invention is desirable to prevent the entry of foreign matter into lung  130 . 
     Pneumostoma Management Device 
       FIGS. 2A and 2B  illustrate a pneumostoma management device (“PMD”)  200  in accordance with an embodiment of the present invention. PMD  200  comprises an implantable sleeve  210  joined at its proximal end  211  with a bulb  220  which may be mounted to the skin of the patient. In a preferred embodiment sleeve  210  is formed in one piece with bulb  220 . In preferred embodiments, sleeve  210  and bulb  220  are formed from biocompatible polymers or a biocompatible metal, for example, stainless steel. 
     Sleeve  210  preferably comprises a rounded distal tip  212  as shown in  FIGS. 2A and 2B . Tip  212  in order to reduce irritation of damage to the tissues of the pneumostoma or lung during insertion or while in position. Sleeve  210  has an opening  214  in tip  212 . Opening  214  allows the entry of gases from the cavity of the pneumostoma into sleeve  210  and thence via the lumen  218  of sleeve  210  to the bulb  220 . 
     Bulb  220  is connected to the proximal end  211  of sleeve  210 . In one embodiment, illustrated in  FIGS. 2A and 2B , bulb  220  comprises a flange  222  and a dome  224 . The flange  222  and dome  224  define a chamber  226 . The chamber  226  has an entrance aperture  228  and at least one exit aperture  230 . Exhaled air and solid material may flow from lumen  218  of sleeve  210  into chamber  226  through entrance aperture  228 . Exhaled air may exit chamber  226  through exit aperture  240  to vent to atmosphere outside of the patient&#39;s body. 
     For simplicity of manufacturing, flange  222 , and dome  224  may be formed in one piece as shown in  FIG. 2B . Bulb  220  has a smooth surface and a low profile so it is comfortable for the patient to wear. Bulb  220  is designed so as not to snag on the patient&#39;s clothing or to restrict motion of the patient. Chamber  226  is sized and configured to receive liquid and/or solid material  290  such as mucous which may be exhaled from the lung through the pneumostoma  110 . 
     Flange  222  is significantly wider than sleeve  210 . Flange  222  thus comprises a contact surface  232  perpendicular to sleeve  210  and surrounding sleeve  210  which, when the sleeve  210  of PMD  200  is positioned in a pneumostoma  110 , will contact the skin of the patient surrounding pneumostoma  110 . The contact surface  232  serves as an insertion limit to prevent over-insertion of sleeve  210  into a pneumostoma  110 . Flange  222  is designed such that it sufficiently flexible that it can conform to the skin  114  of chest  100 . Contact surface  232  is also provided with a biocompatible adhesive  234 , such as a hydrocolloid adhesive, for securing PMD  200  to the skin  114  of the patient. Adhesive  234  should be selected so as to help maintain the correct position of PMD  200  without causing undue irritation to the skin of the patient. 
     A flow control device  240  is positioned in aperture  228  between lumen  218  of sleeve  210  and chamber  226 . Flow control device  240  is positioned and mounted such that material moving between lumen  218  and chamber  226  must pass through flow control device  240 . In the embodiment shown in  FIGS. 2A and 2B , flange  222  is provided with a recess  236  into which flow control device  240  may be mounted. 
     Flow control device  240  may comprise a one-way valve assembly such as a flapper valve, Heimlich valve, reed valve, or the like, for allowing air to be exhaled through entrance aperture  228  into chamber  226  while restricting the flow of air or other matter into lumen  218  from chamber  226 . It is desirable to restrict flow of air in through the pneumostoma so as to encourage a reduction in hyperinflation and to prevent the inhalation of solid or liquid matter from into the lung through the pneumostoma. The flow control device  240  shown in  FIG. 2B  comprises a fixed disc  242  having a number of apertures  244 . Above fixed disc  242  is a flapper disc  246 . Flapper disc  246  is kept in place above fixed disc  242  by hinge  248 . When the air pressure in lumen  218  is greater than the air pressure in chamber  226  during exhalation, flapper disc  246  moves away from fixed disc  242  and air may pass through a space between fixed disc  242  and flapper disc  246  and enter chamber  226  from lumen  218 . However, when the air pressure in lumen  218  is less than the air pressure in chamber  226  during inhalation, flapper disc  246  moves towards fixed disc  242  and obstructs the apertures  244  in fixed disc  242  such that no air may pass into lumen  218  from chamber  226 . 
     A hydrophobic filter  250  is positioned in exit aperture  230  between chamber  226  and the exterior of bulb  220 . Hydrophobic filter  250  is positioned and mounted such that material moving between chamber  226  and the exterior of bulb  220  must pass through hydrophobic filter  250 . Hydrophobic filter  250  prevents the flow of water in and out of chamber  226  through exit aperture  230 . In the embodiment shown in  FIGS. 2A and 2B , bulb  224  is provided with a recess  238  into which hydrophobic filter  250  may be press fit. 
     Use of the Pneumostoma Management Device 
       FIG. 3A  illustrates the use of PMD  200  in pneumostoma  110  of  FIG. 1A . As shown in  FIG. 3A  the low profile of PMD  200  allows it to be inconspicuously positioned on the chest  100  of a patient in the frontal  110  location. PMD  200  is designed so as not to interfere with the range or motion or clothing of the patient. This is of importance for a device such as PMD  200  which must be used continuously to be effective. Comfort and ease of use are important if patient compliance with treatment protocols is to be achieved. 
       FIG. 3B  shows a sectional view through PMD  200  and pneumostoma  110  showing the interaction of the PMD with the pneumostoma  110 . It should be noted that sleeve  210  fits snugly within channel  120  of pneumostoma  110 . Sleeve  210  is sized and configured such that it penetrates through channel  120  into cavity  122  in the parenchymal tissue  132  of lung  130 . Contact surface  232  of flange  222  is pushed into contact with skin  114  of the thoracic wall  106  of chest  100  thus preventing further insertion of sleeve  210 . Adhesive  234  contacts skin  114  holding PMD  200  in position. Flange  222  conforms to the surface of chest  100  to secure PMD  200  to chest  100  with adhesive  234 . 
     Because of the snug fit of sleeve  210  within channel  120  and the contact between flange  222  and/or adhesive  234  with skin  114 , PMD  200  effectively controls the movement of all material in or out of the pneumostoma. From lumen  218 , exhaled air flows through flow control device  240  into chamber  226  as shown by arrow  304 . Any liquid and/or solid material  290  remains trapped in chamber  226 . Air flows out of chamber  226  to the exterior of PMD  200  and the patient through hydrophobic filter  250  as shown by arrow  306 . Thus PMD  200  allows air to exit pneumostoma  110  and vent to atmosphere while preventing the entry of water or solids into the pneumostoma  110 . 
     The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.