Abstract:
An attachment for use with a nebulizer for delivery of aerosol medication to respiratory airways of a user has an elongated conduit provided with a one-way valve for admitting ambient air on one of its ends and a mouthpiece—on its opposite end. A calibrated pressure exhalation valve allows escape of exhaled gas once the pressure in the conduit exceeds a pre-determined setting of the valve. The outlet valve is spring-loaded and allows for various calibrations. The conduit is attachable to a nebulizer and facilitates build-up of positive pressure in the user&#39;s sealed airways to help maintain the airways distended for more effective delivery of the medication.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of our allowed co-pending application Ser. No. 09/471,553 filed on Dec. 23, 1999, U.S. Pat. No. 6,412,481, for “Sealed Back Pressure Breathing Device,” the full disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a breathing device adapted for use with a nebulizer for allowing a user to inhale medication particles generated by the nebulizer device through a sealed breathing attachment device. More particularly, the present invention relates to an attachment device for a nebulizer for generating positive backpressure in the airways of the user and to thereby keep the airways open for delivery of the medication to patient&#39;s lungs. 
     Nebulizers are widely used in the medical field for delivery of medicine to patient&#39;s lungs through inhalation. Nebulizers are conventionally used in an emergency, when conventional method dose inhalers (MDIs) fail to reverse a constriction in the airways. The nebulizer is designed to break down the liquid medication into small particles resembling mist. The patient, bringing the medication into the lungs and airways of the user, inhales this mist. 
     The medication that is aerosoled by a nebulizer usually contains a chemical that reacts with receptors in the bronchioles and causes the airways to dilate. The treatments with nebulizers can last up to several hours until the desired result is achieved. If the medication still doesn&#39;t reach the constricted areas in the lungs, stronger medications may be used. Depending upon the severity of the attack, the medications can include steroids, magnesium sulfate, and bronchodilaters. 
     Oftentimes, a patient delivered to an emergency room has a considerable concentration of carbon dioxide in the blood and the use of a nebulizer, which works relatively slow, may require up to eight hours of treatment, dictates that another type of an emergency device, an ambu bag with a mask, is used. The mask seals the area over the patient&#39;s mouth and nose allowing delivery of the aerosol medication. The mask forces the medication into the lungs by positive pressure generated by squeezing the ambu bag. 
     The positive pressure delivers air into the stomach of the patient, as well as into the lungs. When the air is diverted into the stomach it causes gastric distension and vomiting, which in turn, increases the risk of aspiration when the vomited medium is inhaled or forced into the lungs. 
     The most critically ill patients who do not respond to the treatment with conventional nebulizers or ambu bags are put on a ventilator, an artificial breathing machine that includes placing an endotrachial tube into the trachea of the patient. The tube has an inflated cuff for sealing the inhaling airway. Then the patient can be ventilated by positive pressure. Since the patient is sedated when he is on the breathing machine, the medication produced by the nebulizer can be more effectively delivered to the patient&#39;s lungs. 
     However, this drastic method suffers from serious disadvantages. The strong positive pressure drives the air into the lungs, sometimes causing damage by excessive pressure, or by excessive volume of air forced into the lungs. In some instances, the patient&#39;s inspiratory muscles atrophy, particularly in the case where the patient remains on the ventilator for a long period of time. The longer the patient stays on the ventilator, the more difficult it may be to “wean” the patient from the ventilator. 
     The present invention contemplates elimination of drawbacks associated with the prior art through the provision of a sealed back pressure attachment device for a nebulizer that creates positive pressure on the constricted airways and causes the airways to stay open for delivery of medication. With the use of the device according to the instant invention the patient&#39;s airways are incorporated into a closed circuit with the attachment device. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a sealed back pressure attachment for a nebulizer device that would allow creation of positive end expiratory pressure on the constricted airways of a patient suffering from asthma, emphysema, or other respiratory illness. 
     It is another object of the present invention to provide a sealed backpressure slow breathing attachment device for a nebulizer that can be pre-set to create the desired amount of pressure within the device to help restore a person&#39;s breathing to their normal physiological state. 
     It is a further object of the present invention to provide an attachment device for a nebulizer that seals the backpressure and equalizes the pressure behind the terminal bronchial path. 
     It is still a further object of the present invention to provide a sealed backpressure attachment device for a nebulizer that can be calibrated for creating a predetermined amount of pressure in the airways of a patient. 
     It is still a further object of the present invention to provide a scaled backpressure attachment device for a nebulizer that is simple to use and inexpensive to manufacture. 
     These and other objects of the present invention are achieved through a provision of a sealed backpressure attachment device for a nebulizer that comprises a manifold and an elongated conduit/mixing reservoir made from a flexible resilient material. The conduit/reservoir has a one-way inlet valve for admitting ambient air into the conduit and a mouthpiece for engaging by a user&#39;s mouth. A spring-loaded calibrated adjustable pressure valve is mounted in fluid communication with the interior of the conduit to allow exhaled gases to be vented into the atmosphere. 
     A manifold is secured on the conduit between a mouthpiece and the calibrated pressure valve, the manifold having one portion that extends in a substantially co-axial relationship to the central axis of the conduit and a second portion that extends perpendicularly to the conduit central axis. The second portion of the manifold acts as a nebulizer connector in one embodiment and a nebulizer/pressure valve connector in the second embodiment. The manifold allows to detachably secure the sealed backpressure attachment device to a nebulizer. The manifold is mounted between the pressure valve and the mouthpiece. 
     When the user inhales, the ambient air is admitted into the conduit and draws aerosol medication from the nebulizer into the hollow conduit/mixing reservoir, delivering the medication into the mouthpiece and then into the user&#39;s respiratory system. When the user exhales, the one-way valve effectively prevents escape of exhaled gas through the first end of the conduit. Instead, the exhaled gas is diverted to the calibrated pressure exhalation valve, which is provided with an outlet port. 
     The gas pressure builds up until it is greater than the pre-set value of the valve. At that time, positive backpressure keeps exhaled gas in the user&#39;s sealed airways, which in turn causes collapsed or constricted air passages to stay open. Only after the pressure exceeds the pre-determined value the exhalation gas is allowed to escape into the atmosphere. Following this period, the medication particles are delivered into the lungs and airways of the patient, during inspiration. 
     The pressure exhalation valve may be preset in the range of between 5 cm of water to 10 cm of water although other pressure values may be used for the calibration of the valve, if desired. This application works because it is a sealed backpressure environment. 
     The present invention may be used as attachment for conventional nebulizers or, with certain modifications, with other respiratory emergency devices. The device of the present invention is believed to be particularly useful for asthma and emphysema sufferers, although other respiratory problems treatable with inhaled medications may benefit from the concept set forth in this application and the mechanical device disclosed herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference will now be made to the drawings, wherein like parts are designated by like numerals, and wherein 
     FIG. 1 is a perspective view of the attachment device according to the first embodiment of the present invention mounted on a standard nebulizer. 
     FIG. 2 is a perspective view of the second embodiment of the device in accordance with the present invention. 
     FIG. 3 is a partially exploded view of the second embodiment of the device of the present invention. 
     FIG. 4 is a perspective view showing the airflow through the device of the present invention during inhalation. 
     FIG. 5 is a perspective view showing the airflow through the device of the present invention during expiration. 
     FIG. 6 is perspective view of the device of the present invention as used with a face mask. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings in more detail, numeral  10  designates the attachment device in accordance with the first embodiment of the present invention. The device  10  is detachably secured to a conventional nebulizer  12  for operation. The device  10  comprises an elongated hollow conduit/mixing reservoir  14  made of a flexible, resilient material, such as for example, corrugated plastic tubing. The conduit  14  may be stretched through the expansion of corrugations  16  schematically shown in FIG.  1 . The conduit  14  acts as a reservoir for collecting aerosolized medication. In this application, the words “conduit  14 ” and “reservoir  14 ” are used interchangeably. 
     A one-way valve  18  is mounted on one open end of the conduit  14  to allow intake of air from the exterior of the device  10 . The one-way valve  18  prevents exhaled gases from escaping the conduit  14  during exhalation. 
     An opposite end  20  of the conduit  14  receives, in a frictional engagement, a mouthpiece  24 . The mouthpiece  24  is detachably engaged, such as by threads (FIG. 3) to a manifold  30 . The mouthpiece  24  is provided with an opening (not shown) permitting the user to inhale and exhale through the mouthpiece during operation of the device. 
     A three-way manifold  30  is mounted adjacent to the second end  20 . The manifold  30  is provided with a first tubular member  32  that extends substantially coaxilly with a conduit  14  and a second, transverse member  34  that extends perpendicularly to the longitudinal axis of the conduit  14 . The second portion  34  of the manifold  30  opens for direct communication with the interior of the conduit  14  for purposes, which will be explained in more detail hereinafter. 
     The second portion  34  of the manifold  30  is adapted for detachable engagement with an outlet cap  36  of the nebulizer  12 . Since the nebulizer  12  can be any commercially available device, it is shown in a schematic view in FIGS. 1-6. Conventionally, the nebulizer  12  would have a hollow container  38  adapted for receiving liquid medication  40  inlet gas source therein. An aerosol-forming member  42  is positioned within the hollow housing  38  for drawing the medication from the housing  38  and forming droplets of liquid medication. 
     A fluid communication is established between the interior of the housing  38  and interior of the conduit  14  through the manifold  30  and the mouthpiece  24 . Friction or any other similar means to the second portion  34  can attach the nebulizer device  12  when the device  10  is assembled with the nebulizer. It should be pointed out that the structure of the nebulizer  12  does not form a part of the present invention, and that attachment  10  may be used with other nebulizers available on the market. 
     A second three-way manifold  80  is mounted a distance from the first manifold  30 . The second manifold secures a variable pressure valve  50 , the interior of which is in fluid communication with the conduit  14  and the mouthpiece  24 . The valve  50  is a one-way exhalation valve allowing exhaust gases to be vented to the atmosphere after exhalation by the user. The spring pressure valve  50  (PEEP valve) may be selected from a number of available valves made by different manufacturers. 
     The valve  50  has a spring  52  mounted therein to offer resistance to the opening of the valve during exhalation. The spring  52  is pre-set for controlling the amount of resistance offered to the gas flow and can be set to between 5 cm and 10 cm of water. 
     Of course, lower and higher values of the pressure may be set at the manufacturing facility, if desired, depending on the requirements of the medical practitioners. It is envisioned that the valves  50  may be color-coded, depending upon the calibration, with different colors corresponding to different values of pre-set pressure. 
     The valve  50  is mounted on the conduit  14  with the use of a perpendicular part  58  of the manifold  80 . The member  58  frictionally seals the inlet  56  of the valve  50  and connects the valve  50  to the conduit  14 . The valve  50  has a cylindrical portion  54 , which is in fluid communication with the inlet  56 . An exhaust opening  70  if formed in the valve  50  to allow exhaust gas to exit the attachment  10 . An adjustable cap  62  of an upper housing  60  is threaded through a steel rod  82  against spring  52  engaged an enlarged diameter flange  64  to a lower portion  66  of the valve  50 . The cap  62  is used to preset the tension on the spring  52  for controlling the pressure value in the conduit  14 . The upper housing  60  may be frictionally fitted against an upwardly facing smaller diameter shoulder  68  formed on the body  66  as shown in FIGS. 1-6. 
     FIGS. 2 and 3 illustrate the second embodiment  100  of the device of the present invention. The device  100 , similarly to the device  10 , comprises an elongated conduit/mixing reservoir  114 , a mouthpiece  124 , an inlet one-way valve  118  and an exhalation one-way valve  150 . The conduit  114  has a proximal end  120  adjacent the mouthpiece  124 . The conduit  114  has a flexible, resilient portion  116 , similar to the portion  16  of the device  10  of the first embodiment. In this embodiment, however, the manifold  130  is a four-way manifold that has a longitudinal portion  132  and a cross portion  134 . In the second embodiment, the vertical axis of the exhaust valve  150  is oriented substantially co-axially with the center of the outlet cap  136  of the nebulizer housing  138 . 
     Similarly to the device  10 , the mouthpiece  124  is threadably engaged (see FIG. 2) with the manifold  130 , and the part  134  of the manifold  130  frictionally engages with the cap  136  of the nebulizer  112 . The nebulizer  112  has medication source  140  and an aerosol forming member  142  mounted in the nebulizer housing  138 . 
     The pressure exhalation valve  150  has a steel rod  158  carrying a spring  152  that is preset with the help of an adjustable cap  162 . The valve  150  has an upper housing  160 , which is closed on top by the cap  162 , and a lower portion  166 . The lower portion  166  houses an inlet  156 . An exhaust opening  170 , similar to the opening  70  of the first embodiment, allows exhaust gas to exit the attachment  100 . The second embodiment is more compact, with the conduit  114  being shorter than the conduit  14  since there is no length of tubing extending between the two manifolds, as in the first embodiment. Operation of both embodiments, however, is the same. 
     Turning now to FIGS. 4 and 5, the operation of the device  10  will be discussed in more detail. As can be seen in the drawings, when the user inhales, air is drawn from the atmosphere through the inlet valve  18  into the conduit  14 . The airflow, schematically designated by arrows  72 , travels directly through the reservoir  14 , manifold  80 , manifold  30  into the mouthpiece  24 . 
     At the same time, the pressure created within the conduit  14  causes medication  40  to enter the aerosol-forming member  42  of the nebulizer  12  and move into the manifold  30 , intercepting the airflow. The medication  40 , having been mixed with air and broken into tiny droplets in the form of mist joins with the inlet airflow and is delivered into the airways of the user through the mouthpiece  24 . 
     It is preferred, that during inhalation and exhalation, the patients have their lips closely sealed against the mouthpiece  24 , so as to allow the device  10  to provide effective medication delivery and exhalation of gases. In the alternative, a facemask may be used, particularly with severely ill patients. This type of application is shown in FIG.  6 . 
     During an asthma attack, medication often cannot reach the dilation receptors due to a massive bronchiole constriction and inflammation of the walls of the airways. If the medication cannot be directed to the affected area the constriction will continue to persist. With the attachment  10  of the present invention, when the patient exhales, the valve  50  that helps to distend airways and to prevent collapsing of the alveoli creates a positive backpressure. 
     When the positive back pressure is created in the conduit  14 , the exhaled air is forced to exit only through the valve  50  that has been pre-set to offer resistance to the flow of gas being exhaled. The exhaust airflow, schematically illustrated by arrows  74  in FIG. 5, cannot exit through the valve  18  since it is a one-way valve. The spring loaded variable pressure exhalation valve  50  with its gas outlet port  70  becomes the only exit for the gas. 
     By keeping a sealed positive back pressure the airways are kept open. The device  10  allows trapped carbon dioxide to escape through the opening  70 , thereby reducing hyper inflation and toxic levels of carbon dioxide in the bloodstream of the user. As the trapped gases are removed from the lungs, the lungs can generate a greater inspiratory pressure with less effort of the user. 
     Once the airways are expanded, a pyramid effect begins to take place. A long expiratory phase is experienced allowing equalization of pressure and volume in all lung areas. Since the airway is stented it allows better air movement into the lungs and out of the lungs. The lungs are therefore not hyperinflated, allowing fresh air to enter the lungs. Consequently, the medicine  40  pulled in from the nebulizer  12  more effectively reaches the affected areas of the lungs, further dilating the airways. 
     The present invention can also be effectively used with patients suffering from emphysema. With such illness, the air spaces distal to the terminal bronchioles are weakened and are in a permanently enlarged condition. The alveolar walls are oftentimes damaged. The alveolar sac composed of tightly clustered alveoli disintegrates into larger air spaces. Because of the loss of alveoli, the amount of surface area for gas exchange is reduced and the elastic recoil of the lung tissue is compromised. 
     Emphysema patients have trouble exhaling because the alveoli no longer stretches and contracts with the same elasticity as in healthy lungs. Because of inadequate lung recoil, inspiratory muscles are fatigued. The lungs are unable to properly relax and return to their normal position. The inspiratory muscles remain somewhat contracted at the end of exhalation and, consequently, they are unable to filly contract with the next inspiration. 
     At the same time, if bronchial tubes are unable to support themselves against the pressure generated during the expiratory phase they tend to collapse. In cases like this, accessory muscle use with pursed lip breathing tends to create inconsistent back pressure, which may keep the bronchioles open. Using the attachment device  10  for the nebulizer  12 , the patient can deliver the vital medication into the lungs and help dilate the airways. 
     The provision of the spring-loaded pressure exhalation valve  50  imitates “pursed lip breathing” when the patient exhales because backpressure is created by the valves  50  and  18 . This backpressure prevents the bronchioles alveoli from collapsing. An open airway on exhalation allows for the escape of carbon dioxide reducing the level of that gas in the utser&#39;s bloodstream. 
     When the exhaled gas escapes through the opening  70 , the hyperinflation of the lungs is substantially reduced. The device  10  helps emphysema patients in a number of important ways. For example, the variable pressure valve  50  keeps the airways open, preventing the collapse of the alveoli and airways on expiration. As a result, the air is not trapped in the lungs and hyperinflation of airways is reduced. 
     The reduction in hyperinflation allows the user to inspire and exhale more fully, thereby delivering the medication  40  to a greater surface of the damaged tissue. Even further, by keeping the alveoli and airways open, the exhaled carbon dioxide moves more freely from the lungs into the atmosphere through the openings  70 ,  170  thereby reducing carbon dioxide levels in the user&#39;s bloodstream. 
     By creating positive backpressure within the conduit/reservoir  14  during exhalation, the air is not forced into the lungs and stomach of the user on inspiration. The backpressure, while not forcefully admitting air into the lungs and the stomach of the user, expands and keeps open the affected bronchial passages. This expansion allows for effective gas exchange as required for normal physiological function of the human body. The open air passages allow more medication and oxygen to be delivered into the lungs, substantially facilitating the treatment of obstructive pulmonary diseases. 
     It is believed that the present invention may assist other patients with respiratory problems by creating a sealed positive backpressure and slowing the air movement that keeps the tubular airways dilated for delivery of the medication and exhaling of carbon dioxide. It is envisioned that the valves  50 ,  150  can be pre-set to greater values, particularly with patients having considerable problems with collapsed airways, although the preferred settings would range between 5 to 10 cm of water. By creating an artificial harrier to the exhalation of gas, the lateral wall pressure helps retain the walls in the distended condition, depending on the calibration set for the valves  50 ,  150 . 
     It is within the scope of the present invention that the mouthpiece  24  can be replaced with a strapped facemask  86  on the end  20  of the conduit  14 . The mask will be particularly useful in treating patients who are unable to assist medical personnel in controlling the seal around the mouthpiece. The mask covering mouth and nose of the patient may be available for use with patients that are unconscious or physically infirm to keep the lips tightly closed around the mouthpiece  24 , to create a close circuit with the device. 
     It is further envisioned that the attachments  10 ,  100  of the present invention may be used for exercising the patients and restoring their ability to normally breathe. It is also envisioned that a nose clip and/or cushioned mouthpiece may be used in combination with the mouthpieces  94 ,  194  to better insure a sealed passageway between the conduits  14 ,  114  and the airways of the user. 
     By using a sealed backpressure environment, the sealed backpressure attachment devices  10 ,  100  of the present invention allows the patients to experience a long expiratory phase and keep the collapsed or obstructed airways open. This, in turn, allows delivering medication to the areas where the medication is needed most, to the sites affected by inflammation, constriction, and the like. Consequently, more precise medication delivery is achieved and the treatment is more effective with less medication. 
     Attachment devices  10 ,  100  of the present invention provides an effective alternative to the use of ambu bags where the air is artificially forced into the patient&#39;s body through the airways, reaching the lungs and stomach in a strong dynamic flow. The less traumatic creation of backpressure through the use of the present invention is therefore believed to be more beneficial for collapsed and obstructed airways of asthmatic and emphysema patients, as well as for persons suffering from other respiratory problems. 
     Many changes and modification may be made in the design of the present invention without departing from the spirit thereof. We, therefore, pray that our rights to the present invention be limited only by the scope of the appended claims.