Abstract:
Current methods of drug administration to the lungs are inefficient. ‘Endotracheal Tube with Aerosol Delivery Apparatus II’ is specifically designed for uniform intrapulmonary delivery of aerosolized medication in patients on mechanical ventilation. As opposed to the current methods of drug delivery where aerosol particles are generated at the proximal end of the ETT, with majority of the particles adhering to the endotracheal tube during delivery, this invention bypasses the endotracheal tube by generating aerosol particles at its distal end. This invention incorporates 1 to 6 (preferably 4 to 6) secondary cannulations in the wall of the ETT with pinhole terminal orifices at the distal tip of the ETT arranged symmetrically. The secondary cannulations continue proximally as semi-flexible tubules that terminate as MDI adapters to fit the nozzle of MDI canister. This device generates 1-6 aerosol plumes. Numerous variations in the ID, shape, trajectory and location of the secondary cannulations and distal orifices in the wall of the ETT generate aerosol plumes with velocity, geometry, particle size and orientation that ensures effective aerosol delivery to the respiratory system.

Description:
REFERENCE TO THE RELATED APPLICATION  
       [0001]    The present application incorporates by reference the copending application entitled “ENDOTRACHEAL TUBE WITH AEROSOL DELIVERY APPARATUS” found by the same inventor of the present application and on the even date here with and assigned serial number 10/072,282 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to medical-surgical devices for intubation i.e. endotracheal tube (ETT) intended for tracheal insertion in patients requiring mechanical ventilation. This tube is specifically designed for improved intrapulmonary deposition of aerosol particles both quantitatively as well as qualitatively in patients on mechanical ventilation via endotracheal tube. Multiple medications readily lend themselves for pulmonary administration. Many diagnostic and therapeutic agents that can be utilized through this route are the bronchodilators, anti-inflammatory agents like steroids, antibiotics, anticholinergics, heparin, surfactant, antiproteases, gene transfer products, insulin, radioactive dyes, etc.  
           [0003]    The advantages of intrapulmonary drug delivery as opposed systemic administration are well known. The desired effect at the site of local delivery as opposed to systemic administration minimizes side effects and is the preferred methodology for delivery of several medications. Conventional methods for aerosol delivery have resulted in failure of effective drug delivery to the lungs. They are limited not only in total dose delivery but have also failed to achieve uniform intrapulmonary drug distribution. The two methods currently available for intrapulmonary drug delivery are highly inefficient. They are:  
           [0004]    (I) Liquid bolus: The medication is instilled in the form of liquid bolus via a bronchoscope or through an ETT. The distribution by this method is non-uniform. Also there is a significant risk of inducing respiratory distress and hypoxemia.  
           [0005]    (II) Aerosol Inhalation: Conventional methods of aerosol drug delivery have employed Metered Dose Inhalers (MDI&#39;s) with low boiling point propellants (CFC, HFA) or aerosol particles generated by heat, traditional compressed air nebulizers, or ultrasonic nebulizers. Even though these methods produce aerosol particles in respirable range (&lt;5 microns) compared with the liquid bolus medication, they are limited in total dose delivery and lack uniform distribution of medication to the lungs. Only a small fraction of the medication reaches the lungs as the majority of the aerosol particles either adhere to the nasal passages and oropharynx or are exhaled out. Efficiency of aerosol delivery drops even further in patients who are intubated and require mechanical ventilation. Beck et al found that inhalation of nebulized material through an endotracheal tube resulted in deposition of only 1.87% of the delivered particles to the lungs. Methods employing a combined ventilator dispenser and adapter (U.S. Pat. No. 335,175) or other spacer devices with MDI&#39;s have revealed equally poor results as most of the aerosol particles adhere to the ETT, the connectors and the inspiratory limb of the corrugated plastic tube.  
           [0006]    Investigators over the years have designed numerous endotracheal tubes in an attempt to overcome the hurdles associated with conventional methods of drug delivery to the respiratory system in patients on mechanical ventilation. Most designs of endotracheal tubes so far have only addressed the issue of drug delivery in the form of liquid bolus by incorporating drug irrigation devices in the traditional ETT in the form of secondary canalization with multiple micrometric openings (U.S. Pat. No. 5,146,936).  
           [0007]    Factors that influence uniform delivery of aerosol particles in the tracheobronchial tree are the mid-mean diameter of aerosol particles (which should be in the respirable range, i.e. &lt;5 microns), velocity of the aerosol plume, geometry of the aerosol plume (narrow vs. wide), site of the plume generation (proximal, distal or in the lumen of the ETT), orientation of the plume (central vs. eccentric), time of actuation of MDI in the respiratory cycle, temperature and humidity in the respiratory circuit, etc. These features have not been addressed by any of the currently available endotracheal tubes incorporating drug irrigation devices.  
           [0008]    U.S. Pat. No. 4,584,998 to McGrail describes an ETT with up to three secondary lumens in addition to the primary lumen in which one lumen can serve the purpose of delivering atomized gases to the patient.  
           [0009]    U.S. Pat. No. 4,669,463 to McConnell shows ETT with a secondary lumen in the wall of the main lumen to deliver liquid medication to the respiratory system.  
           [0010]    U.S. Pat. No. 4,821,714 to Smelser also describes an ETT with a secondary lumen to deliver medication to the respiratory system. The second lumen splits into two branches that terminate as two orifices, one at the distal tip and other along the exterior wall of the ETT.  
           [0011]    U.S. Pat. No. 5,504,224 to Anne M. Buret, Pam Jeblenski, and Robert A. Virag describe an ETT with a secondary lumen in the wall of the ETT that terminates at a perforation (Murphy eye). The single stream of medication splits when it Impacts on the distal edge of the opening resulting in delivery of medication both internally and externally of the ETT.  
           [0012]    U.S. Pat. No. 5,642,730 to George Baran later continued as U.S. Pat. No. 6,079,413 assigned to the same inventor describes a catheter system for delivery of aerosolized medicine for use with pressurized propellant canister. The system includes an extension catheter that has a length such that the proximal end is connected to the canister and the distal end is positioned in the primary lumen or secondary lumen of the ETT beyond its distal end in the respiratory system. The system describes an extremely complex methodology for centering the device, attenuating the whipping effect and for preventing impaction losses, especially carinal impaction. Over and above this system is too expensive for clinical utility and is only being used as an experimental tool in research laboratories.  
           [0013]    U.S. Pat. No. 5,964,223 assigned to George Baran describes a nebulizing catheter system similar to U.S. Pat. No. 5,642,730. This system describes the flow of liquid medication through the lumen of a catheter which is nebulized at its tip by a flow of pressurized gas through a coaxial lumen.  
           [0014]    U.S. Pat. Nos. 5,579,758, 5,594,987, 5,606,789, 5,513,630, 5,542,412, 5,570,686 show a delivery device for intratracheal administration of drug in aerosol form called ‘Penn Century Intratracheal Aerosolizer (Microsprayer)’ This device is not related to our field of invention i.e. medical surgical devices for intubation. The clinical utility of this device in humans at this time is extremely limited because of its high cost and need for sterilization after every use and as such it is solely being used as a research tool.  
           [0015]    In summary, none of the prior art ETT&#39;s provide means for effective local delivery of medication to the tracheobrochial tree of both lungs.  
         BRIEF SUMMARY OF THE INVENTION  
         [0016]    The present invention relates to novel endotracheal tubes with an improved system of delivering aerosolized medication to patient&#39;s respiratory system.  
           [0017]    Objects of Invention  
           [0018]    The main object of the present invention is to provide a modified ETT that serves the following purposes:  
           [0019]    Aerosol drug delivery to tracheobronchial tree.  
           [0020]    Generation and delivery of aerosol particles at the distal end of the ETT with mid mean diameter that will allow uniform distribution throughout the tracheobronchial tree.  
           [0021]    Generation and delivery of aerosol particles at the distal end of the ETT such that a significant fraction of the aerosol particles reach the tracheobronchial tree without adherence to the ETT.  
           [0022]    Simple and inexpensive method of intrapulmonary drug delivery  
           [0023]    To achieve all the objects without interfering with the primary functions of the ETT. In other words, the improved system does not impede intubation or in anyway make it more complicated for the operator, or more traumatic to the patient.  
           [0024]    The defined objects are obtained through our present invention i.e. the ETT that incorporates several new features:  
           [0025]    The new system uses a pressurized canister or a metered dose inhaler (MDI) to deliver aerosolized medication to respiratory system. MDI is a system that uses a pressurized canister that contains either a suspension of pulverized particles of medication in a liquid propellant or a solution of the medication in a liquid propellant. When the canister is actuated, the mixture of medication and propellant is generated from the distal orifice or the nozzle of the canister.  
           [0026]    In addition to the primary cannula for inflation of the distal balloon, the ETT has six additional secondary cannulations. The secondary cannulations originate in the proximal half of the ETT and continue distally within the wall of ETT in six different tracts to terminate as six pinhole orifices at the distal tip of the ETT. The six orifices are arranged like the six edges of a hexagon, preferably be at 1, 3, 5, 7, 9 and 11 o&#39;clock positions (other arrangements are possible as well). The secondary cannulations exit the ETT in its proximal half and continue as six narrow tubular extensions outside the main frame of the ETT. The tubular extensions are preferably semi-flexible and terminate as six MDI adapters on the peripheral rim of the circular plate (again arranged like the six edges of a hexagon) or as cylindrical fittings for mating with MDI adapters. The terminal orifice of MDI or nozzle locks into the proximal port of MDI adapter. Actuation of MDI with this assembly would deliver medication at the distal tip of ETT.  
           [0027]    The six flexible tubules are further packaged in a single bigger hollow tube. The hollow tube along with six tubules terminate proximally on the under surface of a circular plate. The distal end of the hollow tube terminates on the outer wall of the ETT, the junction where six flexible tubules mate with six secondary cannulations. The circular plate has a connector in the center through which it attached to a second circular plate. The lower circular plate is fixed to the connector whereas the upper circular plate can freely rotate around the central connector. In the peripheral rim of the proximal circular plate is attached an MDI adapter. The MDI adapter tapers distally to terminate as an orifice that locks into the proximal orifice of the flexible tubule. The connector has a circular groove in the center and six grooves perpendicular to the circular groove equidistant from each other. These perpendicular grooves are in alignment (parallel) with the cylindrical fittings for MDI adapters. The upper circular plate can rotate around the circumference of the circular groove as well as move superiorly and inferiorly along the six perpendicular grooves. This arrangement permits the MDI adapter to move superiorly along the perpendicular groove of the central connector, which unlocks the MDI adapter from the flexible tubule and positions it in the circular groove. Rotation along the circular groove positions it in the next perpendicular groove. On caudal movement of the circular plate the MDI adapter can now lock into the second flexible tubule. Hence, similar repetitive movements would permit the MDI adapter to lock into six flexible tubules one at a time in six different positions. Actuation of the MDI would generate aerosol particles that would be propelled through the MDI adapter into flexible tubules, secondary cannulations and finally to be delivered at the terminal orifices at the tip of the ETT. The aerosolized particles generated at any given orifice will be preferentially delivered to one lung. However, six different aerosol plumes generated from six orifices in different positions would ensure a uniform distribution of aerosol particles to both lungs.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0028]    Further features of the present invention will become apparent in the accompanying drawings as well as the detailed description of the preferred embodiments.  
         [0029]    [0029]FIG. 1 is a plan view of the longitudinal length of ETT according to one embodiment of the present invention, incorporating the features described in the summary of the invention.  
         [0030]    [0030]FIG. 2 is a plan view of the longitudinal length of ETT according to an alternative embodiment of the present invention.  
         [0031]    [0031]FIG. 3 is a plan view of the longitudinal length of ETT according to the most preferred embodiment of the present invention.  
         [0032]    [0032]FIG. 4 is a plan view of the longitudinal length of ETT according to yet another alternative embodiment of the present invention.  
         [0033]    [0033]FIGS. 5 a ,  5   b ,  5   c , and  5   d  are expanded cross-sectional views of the endotracheal tube according to the present invention taken along sections LL 1 , LL 2 , LL 3 , LL 4  of FIG. 1.  
         [0034]    [0034]FIGS. 6 a ,  6   b ,  6   c ,  6   d  are expanded cross-sectional views of the ETT according to the present invention taken along sections LL 5 , LL 6 , LL 7  and LL 8  of FIG. 2.  
         [0035]    [0035]FIGS. 7 a ,  7   b ,  7   c ,  7   d  are expanded cross-sectional views of the ETT according to the present invention taken along sections LL 9 , LL 10 , LL 11  and LL 12  of FIG. 3.  
         [0036]    [0036]FIGS. 8 a ,  8   b ,  8   c ,  8   d  are expanded cross-sectional views of the ETT according to the present invention taken along sections LL 13 , LL 14 , L 15 , and LL 16  of FIG. 4.  
         [0037]    [0037]FIGS. 9 a ,  9   b ,  9   c ,  9   d  are expanded cross-sectional views of the ETT according to an alternative embodiment of the present invention taken along sections LL 13  ,LL 14 , LL 15  and LL 16  of FIG. 4.  
         [0038]    [0038]FIG. 10 is an expanded cross-sectional view of the bottom circular plate of the ETT described in FIG. 3.  
         [0039]    [0039]FIG. 11 is a cross-sectional view of the bottom circular plate of the ETT described in FIG. 4.  
         [0040]    [0040]FIG. 12 is a perspective view of the bottom circular plate of the ETT described in FIG. 3.  
         [0041]    [0041]FIG. 13 is a perspective view of the bottom circular plate of the ETT described in FIG. 4.  
         [0042]    [0042]FIG. 14 is a perspective view of the top circular plate of the ETT described in FIGS. 1 and 2.  
         [0043]    [0043]FIG. 15 is a perspective view of the top circular plate of the ETT described in FIG. 3.  
         [0044]    [0044]FIG. 16 is a perspective view of the top circular plate of the ETT described in FIG. 4.  
         [0045]    [0045]FIG. 17 is a cross-sectional view of the MDI adapter from above as described in FIGS. 14, 15 and  16 .  
         [0046]    [0046]FIG. 18 is a cross-sectional view of the MDI adapter from below as described in FIGS. 14 and 15.  
         [0047]    [0047]FIG. 19 is a cross-sectional view of the adapter from the below as described in FIG. 16.  
         [0048]    [0048]FIG. 20 is a perspective view of the upper and lower plates aligned together as described in FIGS. 3, 10 and  15 .  
         [0049]    [0049]FIG. 21 is a perspective view of the upper and lower plates aligned together as described in FIGS. 4, 11 and  16 .  
         [0050]    [0050]FIG. 22 is a perspective view of an alternative embodiment of the upper and lower plates aligned together as described in FIG. 21.  
         [0051]    [0051]FIG. 23 is a view from above of the direction of the aerosol plume generated from the ETT as described in FIG. 3.  
         [0052]    [0052]FIG. 24 is a view from above of the direction of the aerosol plume generated from the ETT as described in FIG. 4.  
         [0053]    [0053]FIG. 25 is a view from above of the direction of the aerosol plume generated from the ETT as described in FIG. 4 with an alternative embodiment described in FIG. 9 d.    
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0054]    The present invention will now be described in detail by reference to the drawing figures, where as like parts as indicated by like reference numerals.  
         [0055]    [0055]FIG. 1 shows the first embodiment of the present invention. FIG. 1 shows the longitudinal length of an ETT ( 1 ) which may be a conventional adult or pediatric ETT. The ETT is an elongated hollow tube constructed from a plastic material (polymer) or silicone and is approximately 34 cm long if an adult ETT and smaller if pediatric. The internal diameter of the tube can vary from 2.5 mm to 10 mm and the external diameter could vary from 3.5 mm to 13 mm. The thickness of the wall of the tube could vary from 0.5 mm to 2.0 mm. The tube is a flexible elongated conduit with a concave surface on one side and a convex surface on the opposite side. It&#39;s proximal end is connected to an adapter ( 2 ) which enables it to be connected to an elongated tube of a mechanical ventilator. The distal end has a 4 cm expandable cuff ( 3 ) starting approximately 4 cm from the distal tip and ending approximately 8 cm from the distal tip. In the distal 4 cm of the ETT, between the expandable cuff and the distal tip of the ETT, there is a pair of oval holes ( 4 ) one each on the opposite surface of the tube facing each other. The size of the holes can vary between 5 mm and 1 cm. A small tube i.e. primary cannulation ( 5 ) of approximately 1 mm diameter runs within the wall on the convex side of the tube(s) and is connected to the expandable cuff for inflation and deflation by terminating on the outer surface of the ET tube as a 1 mm hole ( 7 ). This tube alternatively can be attached on the outer surface of the tube on the convex side. The primary cannula has a proximal flexible part ( 8 ) which continues outside the main tubular structure of the ETT ( 1 ). The flexible part starts at approximately 18 cm from the distal tip of the ETT and continues proximally for a few centimeters to terminate into a cuff inflation indicator ( 9 ) and adapter ( 10 ) for a syringe. The connection between the flexible and rigid part of the primary cannula is through an opening on the outer surface of the ETT ( 6 ) which is also 1 mm in ID. On the lateral surface of the ETT starting at the same level as the cannulation for the inflation of the balloon ( 6 ) or at a higher level ( 13 ) there originates another secondary cannula ( 11 ) on the outer surface of the ETT that continues within the wall of the ETT. The ID of this secondary cannulation can vary from 0.01 mm to 1.25 mm in size. This secondary cannulation continues distally beyond the balloon to terminate as a pinhole opening ( 12 ) at the distal tip of the ETT. The course of the secondary cannulation within the wall of ETT may be variable and as demonstrated in this figure, it is from the outer surface to the inner surface to terminate at the distal tip of the ETT. The secondary cannulation is an extension of a semi-flexible proximal cannula ( 14 ) which is on the outside of the main tubular structure of the ETT ( 1 ) without adhering to it just like the flexible part of the primary cannula ( 8 ). The semi-flexible cannula ( 14 ) makes a connection with the secondary cannulation ( 11 ) through an opening ( 13 ) on the outer surface of the ETT. The proximal end of the flexible cannula terminates into a metered dose inhaler (MDI) adapter ( 15 ); The flexible cannula maybe an extension of MDI adapter or the two may be fused together if made of different materials. The proximal port of the MDI adapter is designed to fit the nozzle of MDI canister. The distal end of the adapter tapers into a cylindrical tube matable to the flexible canula, the two made of different polymers. This assembly enables aerosolized medication from MDI canister to be delivered at the distal tip of the ETT on actuation of the canister. The device may include a special syringe, the terminal injection port of which may have a configuration identical to the nozzle of MDI. This would enable the MDI port to be used for delivering any liquid medication to the respiratory system via a manually operated syringe or any pressurized source. The port may include a cap for closure when not in use.  
         [0056]    [0056]FIG. 2 shows the longitudinal view of the ETT ( 16 ) associated with alternative embodiments of secondary cannulation. The primary cannulation ( 18 ) runs on the convex wall of the ETT to terminate as an orifice ( 19 ) on the outer surface. This ETT incorporates two secondary cannulations ( 23  and  28 ) as opposed to one shown in FIG. 1. The two points of origin of the secondary cannulations ( 22  and  27 ) as demonstrated in FIG. 2. The secondary cannulations may or may not have similar tracts. They are located on the opposite lateral surfaces of the ETT and continue distally to terminate as two pinhole orifices ( 24  and  29 ) at the distal tip of the ETT. The secondary cannulations ( 23  and  28 ) are extensions of a semi-flexible proximal tubules ( 21  and  26 ) respectively. The flexible tubules are either extensions of the MDI adapters or matable with it as shown in FIG. 1. Also the length of the flexible tubule outside the main tubular structure of ETT could be altered as can the length of secondary cannulations in the wall of the ETT.  
         [0057]    There are numerous varieties of plastic materials that may be used to manufacture the endotracheal tubes (ETT&#39;s); some examples of the same may be—thermoplastics (polyvinyl chloride, polyethylene, polypropylene) silicone, teflon, et; though the one that is most commonly use is polyvinyl chloride (PVC). Since the differences in the compliance and coefficient of friction of various materials could influence the delivery of aerosol medication, the secondary cannulation could be coextruded using a compound or a polymer different from the one used to manufacture the primary ETT. The coextrusion may optimize the physical properties of the secondary lumen and maximize aerosol delivery. Examples of some coextrusions may be—PVC and teflon, PVC and polypropylene, PVC and silicone, PVC and polyethylene, etc. ETT may be disposable or reusable after sterilization.  
         [0058]    [0058]FIG. 3 is the plan view of the most preferred embodiment of our present invention. The detailed description of FIG. 3 and the rationale for this embodiment of ETT will become obvious with the explanation outlined below.  
       PARTICLE SIZE, PLUME CHARACTERISTICS AND DRUG DELIVERY  
       [0059]    Effective drug delivery is closely related to particle size. Larger particles may provide a greater total drug deliver; however, a uniform distribution of medication in the distal tracheobronchial tree requires particle size distribution in the respirable range (&lt;5 microns). Besides particle size, the drug delivery rate and distribution is also a function of the site if aerosol particle generation and the characteristics of the aerosol plume. Even though the size of aerosol particles generated in case of a suspension of pulverized powder medication in a liquid propellant is predetermined and is a function of the size of the crushed solid particles of powder medication, the drug delivery rate and distribution will be tremendously affected by the features of secondary cannulation and the terminal orifice at its&#39; tip. The critical features of secondary cannulations are its length, ID, shape and orientation/trajectory. The features of the distal orifice are its&#39; location, orientation, shape, and ID. All the aforementioned features will also influence the plume geometry, velocity and orientation and hence the distribution of the particles in the distal tracheolbronchial tree.  
         [0060]    In our invention, the ID of the secondary cannulation may be uniform throughout or tapered along the entire length. Alternatively, it may be uniform in the proximal part and tapered near the distal part. The ID of the secondary lumen may vary from 0.01 mm to 1.25 mm. The combined length of the secondary cannulation within the wall of the ETT and its proximal flexible part may also play a critical role in the total drug delivery. A narrow ID of the secondary cannulation is very important for the aerosol medication to reach the distal tip of the secondary cannulation over approximately 25-30 cm of length; however, if the ID is too narrow, it may pose resistance to the flow and impede aerosol delivery. Another very important factor is the course (trajectory) of the secondary lumen in the wall of the ETT. The trajectory may be directed from the outer wall to the inner wall; alternatively the secondary lumen may stay closer to the outer wall throughout; it may stay closer to the inner wall throughout; or it may stay closer to the outer wall for the most part and may be redirected to the inner wall near the distal part of the ETT. A change in the plane of the secondary cannulation in the distal part of the ETT (range 1 mm-10 mm) will change the orientation of the secondary lumen by approximately 5 to 45 degrees. The preferable change in the angle, however, may be 10-15 degrees only in order to prevent tracheal or carinal impaction losses. In another modification of our invention, the secondary cannulation can run inside the primary lumen on the inner wall of the ETT or it could run on the surface on the outer wall of ETT.  
         [0061]    The features of the distal orifice in our invention may also have numerous variations. The distal orifice of the secondary cannulation is located at the tip of the ETT, preferably not in communication with the primary lumen at the ETT and not protruding beyond the distal tip of the ETT. The shape of the distal orifice is preferably circular, however, the shape may be semi circular, lunar, etc. The ID of the distal orifice, which may vary from 0.01 mm to 1.25 mm, may be the same or different from the ID of the secondary cannulation. The ID of the distal orifice may be made extremely small to generate a narrow plume or the terminal orifice may be made larger than the secondary cannulation with splaying in order to generate a wider plume. The location of the orifice may be closer to the inner wall or outer wall or it may be in the center of the ETT&#39;s wall.  
         [0062]    An aerosol plume which is central, and wide will result in a greater fraction of the drug loss due to impaction on the ETT (if generated proximal to the ETT or in the lumen of the ETT) or the wall of the trachea (if generated distal to the ETT) prior to reaching the distal tracheobronchial tree. An aerosol plume that is central, narrow and fast is likely to lose a greater portion of the medication by carinal impaction. An eccentrically located narrow and fast plume will avoid carinal as well as tracheal impaction losses and will ensure aerosol particle delivery to the proximal tracheobronchial tree. The distal tracheobronchial tree delivery may require an eccentric, narrow and slower plume or an eccentric wide and fast plume.  
         [0063]    In our invention the distal orifice of the secondary cannulation is located at the tip of the ETT and generates aerosol at a location in the tracheobronchial tree beyond the ETT, thus avoiding impaction losses. The velocity and width of the plume could be altered by adjusting the shape and ID of the secondary cannulation and the distal orifice. Over and above the orientation of the plume can be influenced by the trajectory of the secondary cannulation. In our invention, since the trajectory is from the outer wall towards the inner wall, preferably in the distal part of the secondary cannulation, the plume will be oriented away from the tracheal wall. The eccentric location of the orifice in the wall of the ETT in our invention is preferable as it prevents carinal and tracheal impaction losses. The diameter of the ETT is far smaller than that of the airway passages i.e. the trachea. On placement of the ETT in the trachea and inflating the distal balloon, the wall of the distal circular edge of the ETT is a few millimeters away from the tracheal wall and hence the orifice located in the wall of the distal tip of ETT. Depending on the size of the ETT the two lateral terminal orifices os secondary cannulations may be located approximately in the center between the carina and the left or right mainstem bronchi.  
         [0064]    One may argue that the lateral location of the orifice would direct the plume preferentially to one lung. This actually may be of tremendous benefit if one wants preferential delivery of medication to one lung which has the pathology. However, if the pathological condition affects both the lungs uniformly the problem can be completely obviated by having two distal orifices diametrically opposite to each other on the lateral surface of the ETT as described in the second embodiment of our invention in FIG. 2. It is also quite conceivable that at the time of placement of the ETT and inflation of the balloon, the ETT may get slightly rotated so that the two lateral orifices may not end up being in the preferred 3 o&#39;clock and 9 o&#39;clock positions. This problem of malaligment of the two lateral orifices with respect to the carina and the right and/or left mainstem bronchi can be overcome by the most preferable embodiment of our invention as described in FIG. 3.  
         [0065]    [0065]FIG. 3 shows the longitudinal view of the ETT ( 30 ) associated with an alternative embodiment of secondary cannulation. FIG. 3 demonstrates the most preferred embodiment of our invention with six secondary cannulations in the wall of ETT terminating in six distal orifices located on the circular edge of the distal tip of ETT. The six orifices may preferably be equidistant from each other like the six edges of a hexagon at 1, 3, 5, 7, 9 and 11 o&#39;clock positions. However, the six orifices may have several alternative symmetric or asymmetric arrangement. The six secondary cannulations and their distal orifices may be identical or completely different from each other in shape, ID, trajectory, and orientation. Such an arrangement would generate plumes with different characteristics i.e. geometry, velocity and orientation. In this respect a preferable arrangement would be to have three orifices on each lateral surface of ETT with the ability to generate narrow and fast, narrow and slow, and wide and fast plumes from the three orifices on each side. In another arrangement, there could be eight secondary cannulations and orifices, four each on the two lateral surfaces in order to generate the wide and slow eccentric plume as well. This arrangement with total eight plumes (¾ plumes with different characteristics and orientation on each lateral surface) will ensure a uniform and effective distribution of aerosol particles to proximal and distal tracheobronchial tree of both lungs.  
         [0066]    [0066]FIG. 3 shows the longitudinal view of the ETT ( 30 ), an adapter at its proximal end ( 31 ) and an inflation cuff ( 37 ). The primary cannula ( 35 ) has a flexible portion ( 33 ), the point of origin of the primary cannula ( 34 ), distal orifice ( 36 ) and proximal cuff inflation indicating an adapter for syringe ( 32 ). There are six secondary cannulations in the wall of the ETT. They originate on the outer surface of the ETT at the same level ( 34 ) or a level higher ( 35 ) than the primary cannula. The six cannulations continue distally in the wall of the ETT to terminate as six orifices, as described before, at the distal tip of the ETT. Two out of six secondary carmulations ( 48  and  49 ) and a single distal orifice ( 47 ) of the secondary cannulation ( 49 ) are demonstrated in FIG. 3. The secondary cannulation continue proximally as six semiflexible tubules ( 45 ) outside the main tubular structure of the ETT( 30 ) without adhering to it just like the flexible part ( 33 ) of primary cannulation. The six flexible tubules are packaged in a larger hollow tube ( 43 ) that terminates distally on the outer wall of the ETT. This arrangement however may be changed and there could be two larger hollow tubes packaging three flexible tubules on each side. The proximal end of the hollow tube ( 43 ) and the six tubules ( 45 ) terminate on the under surface of a circular plate ( 42 ). The six flexible tubules ( 45 ) terminate as six MDI adapters, or alternatively, the six tubules terminate as six rigid cylindrical tubules for mating with MDI adapters on the ventral surface of the circular plate ( 42 ). The circular plate ( 42 ) is attached to another circular plate through a central connector ( 40 ). The central connector ( 42 ) has a circular groove in the center and six grooves perpendicular to the circular grooves that are in alignment (parallel) with the six MDI adapters. The lower circular plate ( 42 ) is fixed to the central connector ( 40 ) whereas the upper circular plate ( 39 ) can rotate around the circular groove as well as move up and down along the perpendicular grooves of the central connector with the help of a handle ( 41 ). Located on the peripheral rim of the ventral surface of the upper plate ( 39 ) is an MDI adapter ( 38 ). The nozzle of a pressurized canister fits into the proximal port of MDI adapter ( 38 ). The MDI adapter tapers distally to terminate on the under surface of the upper circular plate ( 39 ). The MDI adapter ( 38 ) locks into one of the rigid cylindrical tubules, the proximal end of the flexible tubules ( 45 ), located on the dorsal surface of the lower plate. The upper circular plate ( 39 ) can rotate in the circular groove, move superiorly along the perpendicular groove (to unlock) and move inferiorly along the perpendicular groove (to lock) the MDI adapter into six rigid cylindrical tubules one at a time in six different positions. Hence, actuation of MDI in different positions would result in generation of six aerosol plumes at the distal orifices ( 47 ) of the secondary cannulations ( 49 ).  
         [0067]    [0067]FIG. 4 shows an alternative embodiment of our invention to further obviate the tracheal deposition of aerosol particles as well as alter the aerosol particle size. FIG. 4, which shows the longitudinal view of ETT ( 50 ), is identical to the ETT described in FIG. 3 but with two alternative embodiments. The six flexible tubules ( 65 ), and the six secondary cannulations ( 67 ) in the wall of the ETT have two coaxial lumens. The secondary cannulations terminate as two coaxial orifices ( 68 ) at the distal tip of the ETT ( 50 ). The flexible cannulations ( 65 ) are packaged in a hollow tube ( 63 ), the proximal end of which terminates on the dorsal end of the lower circular plate ( 62 ) along with the flexible tubules. The distal end terminates on the outer wall of the ETT ( 64 ). The point of entry or fusion with secondary cannulations ( 66 ) of the six flexible tubules ( 65 ) on the wall of the ETT is demonstrated. The primary cannulations ( 54 ) with all the associated features—distal tip ( 55 ), inflatable cuff ( 56 ), flexible cannula ( 52 ), entry point ( 53 ) and cuff inflation indicator and adapter ( 51 ) are also demonstrated in FIG. 4.  
         [0068]    The second alternative embodiment is a modified MDI adapter ( 57 ) with an additional side port ( 58 ). The upper circular plate ( 59 ) with a handle ( 60 ) along with the central connector ( 61 ) are demonstrated. The MDI adapter has two ports. The main port ( 57 ) that has a proximal port to fit the nozzle of the pressurized canister and a distal orifice that makes an airtight connection with the inner coaxial lumen of the rigid cylindrical tubule. It also has a side port ( 58 ) that communicates with the outer coaxial lumen of the rigid cylindrical tubule. Note that the rigid cylindrical tubule is the proximal end of the flexible tubule for mating with MDI adapter. The inner lumen of the main port of MDI adapter serves to generate aerosol particles by MDI canister or deliver liquid medication via a syringe at the distal tip of the ETT. The side port or the outer lumen of MDI adapter may be used for vapor or gas flow for either anesthesia or to disperse the aerosolized particles generated near the distal tip of ETT away from the trachea as well as to break the particle into smaller size. This device, just like the one described in FIG. 3, incorporates the special feature of MDI adapter&#39;s ability to rotate and lock in six different positions, such that through the inner coaxial lumen liquid medication or aerosol spray is conveyed and the pressurized gas is conveyed in the annular region between the inner and the outer tubular membranes. This coaxial airflow may direct the plume away from the tracheal wall and carina and hence prevent impaction losses.  
         [0069]    A variety of drug delivery rates and particle size distribution can be achieved by altering the coaxial orifice, diameters, pressure and flow characteristics of the liquid and gas in the respective orifices and by adjusting the distance between the liquid and gas flow by altering the thickness of the membrane separating the two lumens. The liquid lumen, the gas lumen and the thickness of the wall separating the two lumens may vary from 0.025 mm to 1 mm.  
         [0070]    In another alternative embodiment of our invention, as described in FIG. 3, there is only one circular plate without a central connector or the upper circular plate. The six flexible tubules terminate into the single circular plate as six MDI adapters on the ventral surface of the plate. They may appear just like the MDI adapter demonstrated in FIG. 1. The nozzle of the MDI canister can fit into the proximal ports of MDI adapters one at a time in six different positions by manual operation. The circular plate may have a cap to cover MDI adapters when not in use.  
         [0071]    In another alternative embodiment of our invention as described in FIG. 4, the inner coaxial lumen of the six flexible tubules may terminate on the ventral surface of the circular plate as MDI adapters and the outer coaxial lumen of the flexible tubules may terminate as six side ports on the outer surface of the circular edge of the single. In another alternative embodiment of our invention, the coaxial arrangement may be uniform and cylindrical for the most part but the inner and/or outer lumen may become semicircular in the terminal part of the ETT. The flow of gas and liquid aerosol in this arrangement would direct the aerosol plume further away from the tracheal wall. In yet another alternative embodiment of our invention, the inner lumen may terminate just proximal to the distal tip of the outer semicircular lumen.  
         [0072]    [0072]FIG. 5 a  is a cross section at level LL 1 , which shows a hollow tube ( 72 ), the wall of the tube ( 71 ), the inner surface of the wall ( 73 ), and the outer surface of the wall ( 74 ).  
         [0073]    [0073]FIG. 5 b  is the same as FIG. 5 a  but with the appearance of an additional secondary cannulation ( 79 ) starting close to the outer wall ( 78 ). The main wall ( 75 ), the inner wall ( 77 ), and the lumen ( 76 ) are demonstrated.  
         [0074]    [0074]FIG. 5 c  is the cross section at the level LL 3 . This is the same as FIG. 5 b , but there may be a change in the position of the secondary cannulation which may stay near the outer wall, move closer to the center move closer to the inner wall of the ETT. There is an additional primary cannula ( 85 ) on the convex side of the ETT near the outer wall for inflation and deflation of the balloon cuff.  
         [0075]    [0075]FIG. 5 d  is the same as FIG. 5 c  but with the absence of primary cannula ( 85 ) as it terminates at a higher level near the expandable balloon. The secondary cannula ( 90 ) may be closer to the inner wall ( 88 ).  
         [0076]    [0076]FIG. 6 a  is the same as FIG. 5 a.    
         [0077]    [0077]FIG. 6 b  is the same as FIG. 5 b  but with the two secondary cannulations ( 105  and  106 ) on lateral surface of the ETT diametrically opposite to each other.  
         [0078]    [0078]FIG. 6 c  is the same as FIG. 6 b  but with an additional primary cannulation ( 107 ).  
         [0079]    [0079]FIG. 6 d  is the same as FIG. 6 c  but two secondary cannulations ( 112  and  113 ) on the lateral surface near the inner wall of the ETT but with loss of primary cannulation ( 107 ).  
         [0080]    [0080]FIGS. 7 a ,  7   b ,  7   c , and  7   d  show the details of four cross sections at four levels, LL 9 - 12  of the ETT as shown in FIG. 3.  
         [0081]    [0081]FIG. 7 a  is the same as FIG. 6 a.    
         [0082]    [0082]FIG. 7 b  demonstrates the main lumen ( 119 ), the wall of the ETT ( 118 ), the inner wall ( 120 ), the outer wall ( 121 ).  
         [0083]    There is appearance of six secondary cannulations ( 22 ) which enter the ETT approximately at the same level but follow different tracts in the wall of the ETT.  
         [0084]    [0084]FIG. 7 c  is the same as FIG. 7 b  but with an additional primary cannula ( 126 ). The six secondary cannulations ( 127 ) however are most separated as they follow different tracts within the wall of the ETT.  
         [0085]    [0085]FIG. 7 d  is the same as FIG. 7 c  but with disappearance of primary cannula ( 128 ). The six secondary cannulations ( 123 ) now appear as the six edges of a hexagon on the distal tip close to the inner wall of the ETT. The six distal orifices may not be equidistant from each other and may be have alternative arrangement along the circular edge of the tip of the ETT.  
         [0086]    [0086]FIGS. 8 a ,  8   b ,  8   c , and  8   d  show details of four cross sections at four levels LL 13 -LL 16  with an alternative embodiment as shown in FIG. 4.  
         [0087]    [0087]FIGS. 8 a ,  8   b ,  8   c , and  8   d  are the same as FIGS. 7 a ,  7   b ,  7   c , and  7   d  respectively; the only difference that is shown here is with respect to the secondary cannulations which have two coaxial lumens as opposed to a single lumen as shown in FIG. 7.  
         [0088]    [0088]FIGS. 9 a ,  9   b ,  9   c , and  9   d  represent another alternative embodiment of the four cross sections at levels LL 13 -LL 16  as demonstrated in FIG. 4.  
         [0089]    [0089]FIGS. 9 a ,  9   b , and  9   c  are identical to FIGS. 8 a ,  8   b , and  8   c.    
         [0090]    [0090]FIG. 9 d  is the same as FIG. 8 d  except for a single modification. The two coaxial secondary cannulations in  9   d  are different from the ones in FIG. 8 d . FIG. 9 d  has circular inner lumen just as demonstrated in FIG. 8 d  but the outer coaxial lumen is semi-circular as opposed to circular as demonstrated in FIG. 8 d . Alternatively, in another embodiment both inner and outer lumen in  9   d  could be semi-circular with the circular edges on the opposite lateral sides.  
         [0091]    [0091]FIG. 10 shows details of a cross sectional view of the lower circular late ( 179 ), the six flexible tubules, three of which have been demonstrated by arrows ( 180 , 181 , and  182 ) that terminate on the ventral surface of the peripheral rim ( 178 ) of the circular plate ( 179 ) like the six edges of a hexagon. The central connector ( 184 ) along with the central attachment are also demonstrated here.  
         [0092]    [0092]FIG. 11 shows the details of the cross sectional view of another embodiment of the lower circular plate that corresponds to FIG. 4. This is the same as FIG. 10, but with a single modification—the six tubules have two coaxial lumens, the inner one ( 191 ) for the liquid medication or liquid aerosol, and the outer one ( 190 ) for the gas or vapour flow. The circular plate ( 186 ), the flexible tubules ( 187 , 188 , and  189 ), the peripheral rim ( 185 ) of circular plate, the central connector ( 193 ), and the central attachment of the plate to the rod ( 192 ) are demonstrated.  
         [0093]    [0093]FIG. 12 is a perspective view of the lower circular plate ( 195 ) shown in FIG. 10. The flexible tubule ( 196 ) terminates ( 195 ) as rigid cylindrical tubule on the ventral surface of the peripheral rim ( 194 ) of the circular plate ( 195 ). Other flexible tubules ( 196  and  197 ) are demonstrated as well.  
         [0094]    [0094]FIG. 13 is a perspective view of the lower circular plate ( 200 ) shown in FIG. 11. The two coaxial tubules—inner ( 205 ) and outer ( 204 ) terminate on the ventral surface ( 203 ) of the circular plate.  
         [0095]    [0095]FIG. 14 shows MDI adapter ( 208 ) as shown in FIGS. 1 and 2. The MDI adapter is located in the center at the circular plate ( 209 ) with peripheral handles ( 210  and  211 ). The MDI adapter tapers distally to continue as a single flexible tubule ( 212 ) that continues as secondary cannulation (not shown) in the wall of the ETT.  
         [0096]    [0096]FIG. 15 shows the upper plate with MDI adapter ( 211 )as shown in FIG. 3. A single MDI adapter ( 211 ) on the peripheral rim ( 212 ) of the circular plate is demonstrated here. The circular plate rotates around a central connector ( 215 ) in the central groove ( 213 ). To facilitate the rotation, the central plate has a handle ( 214 ).  
         [0097]    [0097]FIG. 16 shows upper plate ( 220 ) with MDI adapter ( 217 ) with a handle ( 221 ), a central connector and attachment ( 222 ) as shown in FIG. 4. A single MDI adapter ( 217 ) with a side port ( 218 ) is attached to the circular plate ( 220 ) at its peripheral rim ( 219 ).  
         [0098]    [0098]FIG. 17 shows the top cross sectional view of MDI adapter shown in FIGS. 14, 15, and  16 . The MDI adapter has an inlet port ( 226 ) and two concentric rings ( 225  and  226 ) with decreasing circumferencial perimeter such that the MDI nozzle locks into the innermost concentric ring ( 226 ). The terminal orifice ( 227 ) marks the point of fusion or mating with the proximal end of the flexible tubule. The structure of the internal lumen of MDI adapter could be modified in numerous ways to fit the nozzle of the MDI.  
         [0099]    [0099]FIG. 18 shows the bottom cross sectional view of the MDI adapter shown in FIGS. 14 and 15. The MDI adapter&#39;s innermost ring ( 229 ) to fit the nozzle of MDI and the distal orifice ( 228 ) through which the aerosol particles are generated are demonstrated in this figure.  
         [0100]    [0100]FIG. 19 shows the bottom cross sectional view of the MDI adapter shown in FIG. 16. It is the same as FIG. 18 except for one extra outer ring ( 230 ). The shaded area ( 233 ) between the two rings ( 230  and  232 ) is a tubular hollow space that communicates with a side port ( 218 ) shown in FIG. 16. This hollow space is the coaxial outer lumen.  
         [0101]    [0101]FIG. 20 shows the upper and the lower plates together as shown in FIGS. 3, 12 and  15 .  
         [0102]    [0102]FIG. 21 shows the upper and the lower plates together as shown in FIGS. 4, 13 and  16 .  
         [0103]    [0103]FIG. 22 demonstrates an alternative embodiment of FIG. 21 with the upper and lower plates aligned together. As opposed to the MDI adapter ( 258 ) having a side port for the gas flow, the side port could be a part of the assembly of the lower plate ( 267 ). The central flexible tubule ( 266 ) terminates proximally on the ventral surface ( 265 ) of the lower plate ( 264 ). The side port ( 267 ) terminates proximally ( 268 ) on the dorsal surface of the lower plate. Distally the side port continues as the outer coaxial flexible tubule ( 269 ). The MDI adapter ( 258 ) of the upper plate ( 259 ) locks into the proximal orifice ( 265 ) of the flexible tubule. The MDI adapter can lock in six different positions one at a time with each of the flexible tubules as described earlier. The side port ( 267 ) serves the purpose of gas or vapor flow to the outer coaxial lumen.  
         [0104]    [0104]FIG. 23 shows the cross sectional view of the ETT as shown in FIG. 7 d  along with two dimensional geometry and direction of the plume generated from each of the orifices of secondary cannulations at the distal tip of the ETT. The terminal orifice generates a plume that moves distally along the inner circular edge of the ETT (arrows  274  and  277 ) as well as away from the inner edge (arrow  276 ). The area under the curve of the aerosol plume generated from any one orifice maybe approximately ⅓ to ½ of the area formed by the primary lumen at the endotracheal tube. The six aerosol plumes generated from six distal orifices ensure uniform distribution of medication in the tracheobroncial tree of both lungs as demonstrated.  
         [0105]    [0105]FIG. 24 is the same as FIG. 8 d  with the direction of the plumes as shown in FIG. 23. The airflow in the outer coaxial tube will prevent the tracheal and carnal impaction of aerosol particles.  
         [0106]    [0106]FIG. 25 is the same as FIG. 9 d  with the direction of the plume being further away from the tracheal wall ( 293 ). In this figure the airflow from the semi-circular outer coaxial tube ( 295 ) will redirect the liquid aerosol from the inner lumen ( 294 ) away from the tracheal wall.  
         [0107]    It is noted that the illustration (drawings) and description of the preferred embodiments have been provided merely for the purpose of explanation and although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather the invention intends to all functionally equivalent structures, methods and uses such as are within the scope of the appended claims.