Abstract:
An improved tee type nebulizer unit for medicinal use that delivers a mist of properly sized aerosol particles of medicament to the patient. A uniquely configured air flow baffle assembly, which is strategically positioned within the tee of the nebulizer unit, markedly increases the rate of liquid-to-aerosol conversion compared to prior art tee type nebulizer units. More particularly, due to the positioning and sizing of the air channeling pathways within the air flow baffle assembly, an increase in rate of aerosol mist production by factors of 200%-300% is realized.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to inhalation devices. More particularly, the invention concerns a tee type nebulizer device for medicinal use that delivers an aerosol mist of properly sized particles of medicament to the patient at a very rapid rate. 
     2. Discussion of the Prior Art 
     Delivery of medication to a patient&#39;s lungs by means of jet nebulization has been an accepted procedure in the medical community for many years. Predominantly the device used has been a simple 3-way medical tee with one end interfaced to the patient, the other end open to room air, and the nebulizer component attached to an intermediate third port. Millions of these devices are produced and used annually. 
     Published data (Respiratory Care, Vol. 38, No. 38, Aug. 93; and Advance for Respiratory Care Practitioners Aug. 9, 1993) indicate that the most limiting factor in the use of aerosolized medication is the inefficient mist production by currently available commercial nebulizer systems. Research has shown that most state-of-the-art commercial units deliver less than 10% of the original dose of medication to the patient&#39;s respiratory tract. (Respiratory Care, Vol. 38, #8, August 1993; and AARC Times, June 1993.) 
     Jet nebulization is a process whereby a flow of gas (typically air or oxygen) through a very small orifice creates a partial vacuum in the fluid passageways of the device. This reduction in pressure is sufficient to create a Venturi effect, pulling liquid from a reservoir to mix into the gas stream. This liquid is subsequently changed within the device into aerosol particles. 
     Physical constraints in the design of jet nebulizers for medical use are such that the conversion rate of Liquid-to-aerosol is limited to a maximum of approximately 0.35 ml per minute of operation. This is a determining factor that determines the lengthy time (usually in excess of ten minutes) required for delivery of a clinically effective treatment when using any typical present day tee type nebulizer device. Not only is this wasteful, but because of the excessive time required for delivery of a clinically effective treatment, this type device is not user friendly. It is this problem that the present invention seeks to solve by improving the nebulizer design to include special baffling within the tee adapter of the device. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved tee type nebulizer device that includes a strategically positioned air flow baffle assembly that markedly increases the rate of liquid-to-aerosol conversion. More particularly, due to the positioning and sizing of the air channeling pathways within the air flow baffle assembly, bench studies have shown an increase in rate of aerosol mist production by factors of 200%-300%. 
     Another object of the invention is to provide a device of the aforementioned character that is capable of aerosolizing liquid medicaments at a rate of up to 1 milliliter (ml) per minute. 
     Another object of the invention is to provide a device of the character described that will aerosolize and deliver a clinically viable patient dose (0.2-0.3 mg Albuterol) from a standard 2.5 mg/3 ml nebulizer charge in 3 minutes or less. 
     Another object of the invention is to provide a nebulizer device that is physically small in size for convenience of packaging, storage, dispensing and operation. 
     Yet another object of the invention is to provide a medical aerosol device that is operable with either air or oxygen at flow rates between about 5 and about 8 liters per minute (LPM). 
     Yet another object is to provide a tee/nebulizer device that, can be used in conjunction with various patient interfaces such as a mouthpiece, face mask, or special nasal mask. 
     Another object of the current invention is to provide the capability of readily attaching a commercial filter when needed for exit gas purification prior to atmospheric release. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational, exploded view, partly in cross section of a typical prior art tee type nebulizer device. 
         FIG. 2  is a generally perspective view of one form of the improved tee type nebulizer device of the present invention. 
         FIG. 3  is an enlarged generally perspective exploded view of the body portion of the device shown in  FIG. 2  illustrating the positioning of the baffle assembly of the device within the body portion. 
         FIG. 4  is a generally perspective view of the baffle assembly shown in  FIG. 3 . 
         FIG. 5  is an enlarged cross-sectional view taken along lines  5 - 5  of  FIG. 2 . 
         FIG. 6  is a cross-sectional view taken along lines  6 - 6  of  FIG. 5 . 
         FIG. 7  is a cross-sectional view taken along lines  7 - 7  of  FIG. 5 . 
         FIG. 8  is an enlarged cross-sectional view of the nebulizer portion of the device along with the stand therefore. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings and particularly to  FIG. 1  a typical prior art tee type nebulizer device is there shown. As is apparent from a study of  FIG. 1  the medical tee “T” serves only as an inter-connecting pathway for gas flow between the nebulizer “N”, the patient “P” (at the mouthpiece), and room air “RA” via an elongated breathing tube “BT” that is attached to the exit port “EP” of the medical tee component. The function of the breathing tubing is to limitedly increase device efficiency. 
     Turning now to  FIG. 2  of the drawings, one form of the improved tee type nebulizer unit of the present invention for delivering a multiplicity of particles of aerosolized medication to a patient is there shown and generally designated by the numeral  14 . Nebulizer unit  14  here comprises a nebulizer housing  16  having interconnected top, bottom, side and end walls  18 ,  20 ,  22 ,  24 ,  26  and  28  respectively that cooperate to define an internal chamber  30 . Bottom wall  20  has a nebulizer port  32 , end wall  26  has an inlet port  34  and end wall  28  has a particle outlet port  36  in communication with the patient “P”. 
     Connected to and spanning the top, bottom and side walls  18 ,  20 ,  22  and  24  is an airflow baffle assembly  40 . Airflow baffle assembly  40  ( FIG. 4 ), which forms an extremely important feature of the invention, is strategically located between nebulizer port  32  and inlet port  34  and functions to divide internal chamber  30  into first and second sub-chambers  42  and  44  respectively ( FIG. 2 ). Airflow baffle assembly includes a baffle plate  40   a  having a pair of transversely spaced apart openings  48  formed therein ( FIG. 4 ) and a pair of transversely spaced apart tubular flow directors  50  extending into second sub-chamber  44 . As illustrated in  FIG. 2 , tubular flow director  50  provides fluid communication between the first and second sub-chambers. 
     Connected to particle outlet port  36  is a conventional patient mouthpiece  52  and connected to nebulizer port  32  is a nebulizer assembly  54 . Nebulizer assembly  54 , which also forms an extremely important aspect of the invention, is in communication with second sub-chamber  44  and functions to convert aerosolizable liquid medicament into an aerosolized medication and to then introduce the aerosolized medication into the second sub-chamber. Nebulizer assembly  54  is operable with air and oxygen at flow rates between about 5 and about 8 liters per minute and when functioning in tandem with assembly  14 , aerosolizes liquid medicaments at a rate of up to 1 milliliter (ml) per minute and uniquely will aerosolize and deliver to the patient a clinically viable patient dose of 0.2-0.3 mg of Albuterol from a standard 2.5 mg/3 ml nebulizer charge in less than 3 minutes. 
     Nebulizer assembly  54  here includes a moldable plastic outer body  55  and a moldable plastic central body  56  having a nebulizer orifice  56   a  and a deflector element  56   b  ( FIGS. 5 ,  7  and  8 ). Mounted within the central body portion  56  is an elongated fluid flow tube  60 . Fluid flow tube  60  includes a gas inlet port  62  and a gas outlet port  64  that is in communication with nebulizer orifice  56   a.    
     As best seen by referring to  FIGS. 8 and 5 , nebulizer body  56  is telescopically receivable over flow tube  60  and includes a plurality of circumferentially spaced ribs  68  that cooperate with the outer wall of the flow tube to define a plurality of fluid flow paths  71  ( FIG. 5 ). When the nebulizer body is in position over the flow tube, the components cooperate to define a transverse fluid passageway  74  that is in communication with the plurality of fluid flow passageways  71  and with gas outlet port  64 . With this construction, when the reservoir  76  is filled with the aerosolizable liquid medicament “LM” and when the fluid flow tube  60  is interconnected with a source of gas under pressure “S” via a connector tube  77  ( FIG. 2 ), the aerosolizable liquid medicament “LM” will, in a manner presently to be described, be aerosolized to produce a multiplicity of particles of aerosolized medication. 
     Removably connected to central body portion  60  is a bottom closure assembly  78  that includes a supporting base  80  and an elongated stem  82  that is connected to supporting base  80  in the manner best seen in  FIG. 8  of the drawings. As indicated in the drawings, the fluid flow tube is telescopically, sealably receivable within the elongated stem for sealing the gas inlet port  62  thereof. In one form of the invention, supporting base  80  functions to enable proper positioning of nebulizer for automated robotic filling procedures. In this regard, it should be noted that the overall design of the nebulizer unit of the present invention is such that it is fully compatible with an automated robotic assembly process, with automated robotic post-assembly functional testing and quality assurance inspection, and with automatic robotic packaging processes for packaging and shipping the assembled unit in a fashion that meets the needs of the pharmaceutical companies. 
     As can clearly be seen by referring to  FIG. 2 , when the nebulizer assembly  54  is interconnected with housing  16 , the volume of air surrounding the point of Venturi action “VA” within sub-chamber  44  has been substantially reduced compared to that of the prior art device illustrated in  FIG. 1 . Additionally, and quite importantly, this point of mist production is located immediately beneath the air flow passageway  85  carrying fluids to the patient and the air flow passageway  87  that communicates with room air via the exit port  34 . 
     In using the device of the invention, when the patient inhales the momentary requirement for air flow to the patient lungs typically far exceeds the 6-8 LPM of gas flow to nebulizer  54 . As depicted in  FIG. 5 , upon patient inhalation air is urged to flow through tubular flow directors  50  along a flow path immediately above the port of entry of aerosol from nebulizer  54  into sub-chamber  44 . As this channeled increase in air flow along the edge portions of nebulizer port  32  moves toward the patient, a partial vacuum is created within sub-chamber  44  proximate the area of nebulizer output. This additional partial vacuum, created by the novel baffling assembly  40 , is added to that generated by gas flow through the nebulizer thusly markedly increasing the rate of liquid-to-aerosol conversion. With the proper positioning and sizing of air channeling pathways  50  in the baffle assembly, bench studies have shown an increase in rate of aerosol mist production by factors of 200%-300%. 
     Having now described the invention in detail in accordance with the requirements of the patent statues, those skilled in this art will have no difficulty in making changes and modifications in individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.