Abstract:
An endotracheal tube for insertion into a patient&#39;s trachea includes a drug delivery feature and is formed of an elongated body having a proximal end for connection to a ventilator device and an opposing distal end with a bore formed therein and terminating in at least one ventilation opening. The tube also has at least one drug delivery conduit formed in the elongated body and terminating at one end with a proximal opening and at an opposite end with a distal opening. The proximal opening is adapted to be fluidly connected to a drug delivery device adapter, wherein the at least one drug delivery conduit is separated from the bore along its entire length thereof from the proximal opening to the distal opening. The distal opening is formed at the distal end of the elongated body and is located closer to the distal end than the ventilation opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. patent application Ser. No. 10/162,740, filed Jun. 6, 2002 now abandoned, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     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. 
     BACKGROUND 
     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: (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. (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. Inhalation of nebulized material through an endotracheal tube can generally result in deposition of only 1.87% of the delivered particles to the lungs. Methods have been employed that have a combined ventilator dispenser and adapter 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. 
     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. 
     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. 
     U.S. Pat. No. 4,584,998 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. 
     U.S. Pat. No. 4,669,463 shows ETT with a secondary lumen in the wall of the main lumen to deliver liquid medication to the respiratory system. 
     U.S. Pat. No. 4,821,714 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. 
     Other commercial products include 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. 
     U.S. Pat. No. 5,642,730 and U.S. Pat. No. 6,079,413 each 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. 
     U.S. Pat. No. 5,964,223 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. 
     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. 
     SUMMARY 
     The present invention relates to endotracheal tubes with an improved system of delivering aerosolized medication to patient&#39;s respiratory system. The main object of the present invention is to provide a modified ETT that serves the following purposes: (1) aerosol drug delivery to tracheobronchial tree; (2) 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; (3) 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; and (4) simple and inexpensive method of intrapulmonary drug delivery 
     To achieve all the objects without interfering with the primary functions of the ETT. In other words, the present system does not impede intubation or in anyway make it more complicated for the operator, or more traumatic to the patient. The defined objects are obtained through the present invention, i.e., the ETT that incorporates several features. The present system uses a pressurized canister or a metered dose inhaler (MDI) to deliver aerosolized medication to the 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. 
     In addition to the primary cannula for inflation of the distal balloon, the ETT can have six additional secondary cannulations (conduits). 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 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. 
     The six flexible tubules are preferably 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 permit the MDI adapter to lock into six flexible tubules one at a time in six different positions. Actuation of the MDI generates 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 DRAWING FIGURES 
       Further features of the present invention will become apparent in the accompanying drawings as well as the detailed description of the preferred embodiments. 
         FIG. 1  is a side view of the longitudinal length of an ETT according to a first embodiment of the present invention; 
         FIG. 2  is a side view of the longitudinal length of ETT according to a second embodiment of the present invention; 
         FIG. 3  is a side view of the longitudinal length of ETT according to a third embodiment of the present invention; 
         FIG. 4  is a side view of the longitudinal length of ETT according to a fourth embodiment of the present invention; 
         FIGS. 5   a ,  5   b ,  5   c , and  5   d , respectively, are expanded cross-sectional views of the endotracheal tube according to the present invention taken along sections a-a, b-b, c-c, and d-d of  FIG. 1 ; 
         FIGS. 6   a ,  6   b ,  6   c ,  6   d , respectively, are expanded cross-sectional views of the ETT according to the present invention taken along sections a-a, b-b, c-c, and d-d of  FIG. 2 ; 
         FIGS. 7   a ,  7   b ,  7   c ,  7   d , respectively, are expanded cross-sectional views of the ETT according to the present invention taken along sections a-a, b-b, c-c, and d-d of  FIG. 3 ; 
         FIGS. 8   a ,  8   b ,  8   c ,  8   d , respectively, are expanded cross-sectional views of the ETT according to the present invention taken along sections a-a, b-b, c-c, and d-d of  FIG. 4 ; 
         FIGS. 9   a ,  9   b ,  9   c ,  9   d , respectively, are expanded cross-sectional views of the ETT according to an alternative embodiment of the present invention taken along sections a-a, b-b, c-c, and d-d of  FIG. 4 ; 
         FIG. 10  is an expanded cross-sectional view of a bottom circular plate of the ETT described in  FIG. 3 ; 
         FIG. 11  is a cross-sectional view of a bottom circular plate of the ETT described in  FIG. 4 ; 
         FIG. 12  is a perspective view of the bottom circular plate of the ETT described in  FIG. 3 ; 
         FIG. 13  is a perspective view of the bottom circular plate of the ETT described in  FIG. 4 ; 
         FIG. 14  is a perspective view of the top circular plate of the ETT described in  FIGS. 1 and 2 ; 
         FIG. 15  is a perspective view of the top circular plate of the ETT described in  FIG. 3 ; 
         FIG. 16  is a perspective view of the top circular plate of the ETT described in  FIG. 4 ; 
         FIG. 17  is a cross-sectional view of the MDI adapter from above as described in  FIGS. 14 ,  15  and  16 ; 
         FIG. 18  is a cross-sectional view of the MDI adapter from below as described in  FIGS. 14 and 15 ; 
         FIG. 19  is a cross-sectional view of the adapter from the below as described in  FIG. 16 ; 
         FIG. 20  is a perspective view of the upper and lower plates aligned together as described in  FIGS. 3 ,  10  and  15 ; 
         FIG. 21  is a perspective view of the upper and lower plates aligned together as described in  FIGS. 4 ,  11  and  16 ; 
         FIG. 22  is a perspective view of an alternative embodiment of the upper and lower plates aligned together as described in  FIG. 21 ; 
         FIG. 23  is a view from above of the direction of the aerosol plume generated from the ETT as described in  FIG. 3 ; 
         FIG. 24  is a view from above of the direction of the aerosol plume generated from the ETT as described in  FIG. 4 ; and 
         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 
     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. 
       FIG. 1  shows a first embodiment of the present invention.  FIG. 1  shows a longitudinal length of an ETT  100  which can be a conventional adult or pediatric ETT. The ETT  100  is an elongated hollow tube constructed from a plastic material (polymer) or silicone and is approximately 34 cm in the case of an adult ETT and smaller if for a pediatric application. The internal diameter of the tube  102  can vary from 2.5 mm to 10 mm and the external diameter can vary from 3.5 mm to 13 mm. The thickness of the wall of the tube  102  can vary from 0.5 mm to 2.0 mm. The tube  102  is a flexible elongated conduit with a concave surface on one side and a convex surface on the opposite side. A proximal end  104  is connected to an adapter  110  which enables it to be connected to an elongated tube of a mechanical ventilator (not shown). A distal end  106  has a 4 cm expandable cuff  107  starting approximately 4 cm from the distal tip (end  106 ) and ending approximately 8 cm from the distal tip. In the distal 4 cm of the ETT  100 , between the expandable cuff  107  and the distal tip of the ETT  100 , there is a pair of oval holes  108 , one each on the opposite surface of the tube  102  facing each other. The size of the holes  108  can vary between 5 mm and 1 cm. 
     A first conduit or tube  120 , i.e. primary cannula, of approximately 1 mm diameter runs within the wall on the convex side of the tube(s)  102  and is connected to the expandable cuff  107  for inflation and deflation by being terminated on the outer surface of the ET tube  102  as an opening  122 , such as 1 mm opening. This tube  120  alternatively can be attached on the outer surface of the tube  102  on the convex side. 
     The primary conduit  120  has a proximal flexible part  130  which continues outside the main tubular structure of the ETT  100  and is in fluid communication with the primary conduit  120 . The flexible part  130  starts at approximately 18 cm from the distal tip of the ETT  100  and continues proximally for a few centimeters to terminate into a cuff inflation indicator  140  and adapter  142  for a syringe. The connection between the flexible and rigid part of the primary cannula or conduit  120  is through an opening  129  on the outer surface of the ETT  100  which can be about 1 mm in ID (inner diameter). On the lateral surface of the ETT  100  starting at the same level as the cannulation for the inflation of the balloon  107  or at a higher level (as shown in  FIG. 1 ), a secondary conduit or cannula  150  is provided. A portion of the secondary conduit  150  communicates with a member that extends from the tube  102  as described below, while another portion of the conduit  150  is disposed and formed within the wall of the ETT  100 . The ID of this secondary conduit  150  can vary from 0.01 mm to 1.25 mm in size. 
     This secondary conduit  150  continues distally beyond the balloon  107  to terminate as a pinhole opening  152  at the distal tip of the ETT  100 . The course of the secondary conduit  150  within the wall of ETT  100  is preferably variable. The secondary conduit  150  is in fluid communication with an exterior, semi-flexible proximal cannula or conduit  160  which is on the outside of the main tubular structure of the ETT  100  without adhering to it just like the flexible part  130  of the primary conduit  120 . The semi-flexible conduit  160  makes a connection with the secondary conduit  150  through an opening  154  on the outer surface of the ETT  100 . The proximal end of the flexible cannula terminates into a metered dose inhaler (MDI) adapter  170 . 
     The flexible conduit  160  can be an extension of MDI adapter  170  or the two can be fused together if made of different materials. A proximal port  172  of the MDI adapter  170  is designed to fit the nozzle of MDI canister (not shown). The distal end of the adapter  170  tapers into a cylindrical tube matable to the flexible conduit  160 , the two made of different polymers. This assembly enables aerosolized medication from MDI canister to be delivered at the distal tip of the ETT  100  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 the MDI. This would enable the MDI port  172  to be used for delivering any liquid medication to the respiratory system via a manually operated syringe or any pressurized source. The port  172  can include a cap for closure when not in use. 
       FIG. 2  shows the longitudinal view of an ETT  200  that according to an alternative embodiment illustrated additional secondary conduit features. A primary conduit  210  runs on the convex wall of the ETT  200  to terminate as an orifice  212  on the outer surface. This ETT  100  incorporates two secondary conduits  220 ,  230 , as opposed to one shown in  FIG. 1 . The two points of origin of the secondary conduits  220 ,  230 , as demonstrated in  FIG. 2 , are generally at the same level. The secondary conduits  220 ,  230  may or may not have similar tracts. The conduits  220 ,  230  are located on the opposite lateral surfaces of the ETT  200  and continue distally to terminate as two pinhole orifices  222 ,  232 , respectively at the distal tip of the ETT  100 . The secondary conduits  220 ,  230  are in fluid communication with a pair of respective semi-flexible proximal conduits (tubules)  240 ,  250 , respectively. The flexible tubules  240 ,  250  can be either extensions of the MDI adapters  170  or matable with it as shown in  FIG. 1 . Also the length of the flexible tubule  240 ,  250  outside the main tubular structure of ETT  200  could be altered as can the length of secondary conduits  220 ,  230  in the wall of the ETT  200 . 
     There are numerous varieties of plastic materials that may be used to manufacture the endotracheal tubes (ETT&#39;s) of the present invention; some examples of the same may be—thermoplastics (polyvinyl chloride, polyethylene, polypropylene) silicone, Teflon, etc.; 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. 
       FIG. 3  is a side view of another embodiment of the present invention. The detailed description of  FIG. 3  and the function and operation for this embodiment of an ETT  300  will become obvious with the explanation outlined below. 
     Particle Size, Plume Characteristics and Drug Delivery 
     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 conduits and the terminal orifice at its tip. The critical features of secondary conduits are its length, ID, shape and orientation/trajectory. The features of the distal orifice are its 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. 
     According to the present invention, the ID of the secondary conduit 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 conduit may vary from 0.01 mm to 1.25 mm. The combined length of the secondary conduit 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 conduit is very important for the aerosol medication to reach the distal tip of the secondary conduit 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 conduit 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 conduit 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 the present invention, the secondary conduit can run inside the primary conduit on the inner wall of the ETT or it can run on the surface on the outer wall of the ETT. 
     The features of the distal orifice in the present invention can also have numerous variations. The distal orifice of the secondary conduit is located at the tip of the ETT, preferably not in communication with the primary conduit 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 conduit. 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 conduit 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. 
     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. 
     In the present invention, the distal orifice of the secondary conduit 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 conduit and the distal orifice. Over and above the orientation of the plume can be influenced by the trajectory of the secondary conduit. In our invention, since the trajectory is from the outer wall towards the inner wall, preferably in the distal part of the secondary conduit, 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 of secondary conduits may be located approximately in the center between the carina and the left or right mainstem bronchi. 
     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 the present 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 misalignment 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 . 
       FIG. 3  shows the longitudinal view of the ETT  300  associated with an alternative embodiment of secondary conduit.  FIG. 3  demonstrates an embodiment of the present invention with six secondary conduits or cannulations  302  in a wall  301  of the ETT  300  terminating in six distal orifices  310  located on the circular edge of a distal tip  312  of the ETT  300 . The six orifices  310  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  310  may have several alternative symmetric or asymmetric arrangements. The six secondary conduits  302  and their distal orifices  310  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 the ETT  300  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 conduits 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 (3/4 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. 
       FIG. 3  shows the longitudinal view of the ETT  300 , an adapter at its proximal end  320  and an inflation cuff  322 . A primary conduit  330  has a flexible portion  332 , a point of origin  334  of the primary conduit  330 , distal orifice  336  and proximal cuff inflation indicating an adapter for syringe  340 . There are six secondary conduits  302  in the wall of the ETT  300 . They originate on the outer surface of the ETT  300  at the same level at the point of origin  334  or a level higher than the primary conduit  330 . The six conduits  302  continue distally in the wall of the ETT  300  to terminate as six orifices, as described before, at the distal tip of the ETT  300 . Two out of six secondary conduits  302  and a single distal orifice  310  of the secondary conduit  302  are demonstrated in  FIG. 3 . The secondary conduit continue proximally as six semiflexible tubules  350  outside the main tubular structure of the ETT  300  without adhering to it just like the flexible part  332  of primary conduit  330 . The six flexible tubules are packaged in a larger hollow tube  360  that terminates distally on the outer wall of the ETT  300 . 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  360  and the six tubules  350  terminate on the under surface of a circular plate  370 . The six flexible tubules  350  terminate as six MDI adapters, or alternatively, the six tubules  350  terminate as six rigid cylindrical tubules for mating with MDI adapters on the ventral surface of the circular plate  370 . The circular plate  370  is attached to another circular plate through a central connector  380 . The central connector  380  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  370  is fixed to the central connector  380  whereas an upper circular plate  372  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  374 . Located on the peripheral rim of the ventral surface of the upper plate  372  is an MDI adapter  382 . The nozzle of a pressurized canister fits into the proximal port of MDI adapter  382 . The MDI adapter  382  tapers distally to terminate on the undersurface of the upper circular plate  372 . The MDI adapter  382  locks into one of the rigid cylindrical tubules, the proximal end of the flexible tubules  350 , located on the dorsal surface of the lower plate. The upper circular plate  372  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  310  of the secondary cannulations  302 . 
       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 an ETT  400 , is identical to the ETT  300  described in  FIG. 3  but has two alternative features. Six flexible conduits (tubules)  402  and six secondary conduits  404  in the wall of the ETT  400  have two coaxial lumens. The secondary conduits  404  terminate as two coaxial orifices  406  at the distal tip of the ETT  400 . The flexible conduits  402  are packaged in a hollow tube  410 , the proximal end of which terminates on the dorsal end of a lower circular plate  412  along with the flexible tubules  402 . The distal end terminates on the outer wall of the ETT  400 . A point of entry or fusion  403  represents the joining or mating of the secondary conduits  404  with the six flexible tubules  402  on the wall of the ETT  400  and is illustrated in  FIG. 4 . Primary cannulations  420  with all the associated features, including, distal tip  422 , inflatable cuff  424 , flexible cannula  426 , entry point  428  and cuff inflation indicator and adapter  430  are also demonstrated in  FIG. 4 . 
     According to a second alternative embodiment, a modified MDI adapter  440  with an additional side port  442 . The upper circular plate  444 , with a handle  446 , along with a central connector  448  are demonstrated. The MDI adapter has two ports. The main port  440  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  442  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. 
     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. 
     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  350  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. 
     In another alternative embodiment of our invention as described in  FIG. 4 , the inner coaxial lumen of the six flexible tubules  402  may terminate on the ventral surface of the circular plate  412  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 plate. 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 conduit 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 the present invention, the inner conduit may terminate just proximal to the distal tip of the outer semicircular conduit. 
       FIG. 5   a  is a cross section at level a-a of  FIG. 1 , which shows a hollow tube  108  with a lumen (opening), a wall  109  of the tube  108 , an inner surface  111  of the wall  109 , and an outer surface  113  of the wall  109 . 
       FIG. 5   b  is a cross section at level b-b of  FIG. 1  with the appearance of one additional secondary conduit  150  starting close to the outer surface  113 . The main wall  109 , the inner surface  111 , and the lumen  108  are demonstrated. 
       FIG. 5   c  is the cross section at the level c-c of  FIG. 1 . This view is similar to  FIG. 5   b ; however, the position of the secondary conduit  150  within the wall  109  has been changed in that in this Figure, the conduit  150  is moved closer to a center of the wall  109  and thus closer to the inner wall  111  of the ETT  100 . The primary conduit  120  on the convex side of the ETT near the outer wall for inflation and deflation of the balloon cuff  107  is illustrated. 
       FIG. 5   d  is the same as  FIG. 5   c  but with the absence of the primary conduit  120  as it terminates at a higher level near the expandable balloon. In this embodiment, the secondary cannula  150  is closer to the inner wall  111 . 
       FIG. 6   a  is the same as  FIG. 5   a  but for the ETT  200  and is therefore taken along the line a-a of  FIG. 2 . 
       FIG. 6   b  is the same as  FIG. 5   b  but taken along the line b-b of  FIG. 2 , with the two secondary conduits  220  on lateral surface of the ETT  200  diametrically opposite to each other. 
       FIG. 6   c  is the same as  FIG. 6   b  but with one primary conduit  210  as taken along the line c-c of  FIG. 2 . 
       FIG. 6   d  is the same as  FIG. 6   c , but taken along the line d-d of  FIG. 2 , with two secondary conduits  220  on the lateral surface near the inner wall of the ETT  200  but without the primary conduit  210 . 
       FIGS. 7   a ,  7   b ,  7   c , and  7   d  show the details of four cross sections at four levels, a-a, b-b, c-c, d-d, respectively, of the ETT  300  as shown in  FIG. 3 . 
       FIG. 7   a  is the same as  FIG. 6   a  but for the ETT  300 . 
       FIG. 7   b  demonstrates a main lumen  301 , a wall  303  of the ETT  300 , an inner wall  303 , and an outer wall  305 . 
     There is appearance of six secondary conduits  320  which enter the ETT  320  approximately at the same level but follow different tracts in the wall of the ETT  300 . 
       FIG. 7   c  is the same as  FIG. 7   b  but with one additional primary conduit. The six secondary conduits  320 ; however, are most separated as they follow different tracts within the wall of the ETT  300 . 
       FIG. 7   d  is the same as  FIG. 7   c  but with disappearance of primary conduit  330 . The six secondary conduits  320  now appear as the six edges of a hexagon on the distal tip close to the inner wall of the ETT  300 . The six distal orifices  310  may not be equidistant from each other and may be have alternative arrangement along the circular edge of the tip of the ETT  300 . 
       FIGS. 8   a ,  8   b ,  8   c , and  8   d  show details of four cross sections at four levels a-a, b-b, c-c, and d-d, respectively, with respect to the alternative embodiment as shown in  FIG. 4 . A main lumen  431 , a wall  433  of the ETT  400  that includes inner wall  437  and outer wall  439  are illustrated. 
       FIGS. 8   a ,  8   b ,  8   c , and  8   d  are the same as the embodiments of  FIGS. 7   a ,  7   b ,  7   c , and  7   d  respectively; with the only difference being that the secondary conduits  404  of  FIGS. 8   a - 8   d  have two coaxial lumens as opposed to a single lumen as shown in  FIG. 7 . 
       FIGS. 9   a ,  9   b ,  9   c , and  9   d  represent another alternative embodiment of the needle  400  of  FIG. 4 .  FIGS. 9   a ,  9   b , and  9   c  are identical to  FIGS. 8   a ,  8   b , and  8   c .  FIG. 9   d  is the same as  FIG. 8   d  except for a single modification. The two coaxial secondary conduits  404  in  9   d  are different from the ones in  FIG. 8   d .  FIG. 9   d  has circular inner lumen  431  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  can be semi-circular with the circular edges on the opposite lateral sides. 
       FIG. 10  shows details of a cross sectional view of the lower circular plate  412 , the six flexible tubules  402  are formed at or near the ventral surface of the peripheral rim of the circular plate  412  like the six edges of a hexagon. The central connector  448 , along with the central attachment, is also demonstrated here. 
       FIG. 11  shows the details of a cross-sectional view of another embodiment of the lower circular plate  412  that corresponds to the embodiment of  FIG. 4 . This is similar to  FIG. 10 , but with a single modification, namely, that the six tubules  402  have two coaxial lumens, an inner one  403  for the liquid medication or liquid aerosol, and an outer one  405  for the gas or vapor flow. The circular plate  412 , the flexible tubules  402 , the peripheral rim of the circular plate  412 , the central connector  448 , and the central attachment of the plate  412  to a rod  419  are demonstrated. 
       FIG. 12  is a partial perspective view of the lower circular plate  412 . Each of the flexible tubule  402  terminates as rigid cylindrical tubule on the ventral surface of the peripheral rim of the circular plate  412 . 
       FIG. 13  is a partial perspective view of the lower circular plate  412  shown in  FIG. 11 . The two coaxial tubules—inner  403  and outer  405  terminate on the ventral surface of the circular plate  412 . 
       FIG. 14  shows MDI adapter  170  as shown in  FIGS. 1 and 2 . The MDI adapter  170  is located in the center at a circular plate  171  with peripheral handles  173 ,  175 . The MDI adapter  170  tapers distally to continue as a single flexible tubule  177  that extends as secondary conduit (not shown) in the wall of the ETT. 
       FIG. 15  shows the upper plate with MDI adapter  382 , as shown in  FIG. 3 . A single MDI adapter  382  on the peripheral rim of the circular plate  372  is demonstrated here. The circular plate  372  rotates around the central connector  380  in a central groove  383 . To facilitate the rotation, the central plate has the handle  374 . 
       FIG. 16  shows upper plate  444  with MDI adapter  420  with the handle  446 , a central connector and attachment  448  as shown in  FIG. 4 . A single MDI adapter  440  with a side port  442  is attached to the circular plate  444  at its peripheral rim. 
       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  500  and two concentric rings  502 ,  504  with decreasing circumferential perimeter such that the MDI nozzle locks into the innermost concentric ring  504 . The terminal orifice  506  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. 
       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 to fit the nozzle of MDI and the distal orifice  509  through which the aerosol particles are generated are demonstrated in this figure. 
       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  510 . The shaded area  512  between the two rings  510 ,  514  is a tubular hollow space that communicates with a side port  442  shown in  FIG. 16 . This hollow space is the coaxial outer lumen. 
       FIG. 20  shows the upper and the lower plates together as shown in  FIGS. 3 ,  12  and  15 . 
       FIG. 21  shows the upper and the lower plates together as shown in  FIGS. 4 ,  13  and  16 . 
       FIG. 22  demonstrates an alternative embodiment of  FIG. 21  with the upper and lower plates aligned together. As opposed to the MDI adapter having a side port for the gas flow, the side port  520  could be a part of the assembly of the lower plate  412 . The central flexible tubule  402  terminates proximally on the ventral surface  522  of the lower plate  412 . The side port  520  terminates proximally on the dorsal surface of the lower plate  412 . Distally the side port continues as the outer coaxial flexible tubule  405 . The MDI adapter  440  of the upper plate locks into the proximal orifice of the flexible tubule  402 . The MDI adapter  440  can lock in six different positions one at a time with each of the flexible tubules as described earlier. The side port  520  serves the purpose of gas or vapor flow to the outer coaxial lumen. 
       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  530  and  532 ) as well as away from the inner edge (arrow  534 ). 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  301  at the endotracheal tube  300 . The six aerosol plumes generated from six distal orifices ensure uniform distribution of medication in the tracheobroncial tree of both lungs as demonstrated. 
       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 carinal impaction of aerosol particles. 
       FIG. 25  is the same as  FIG. 9   d  with the direction of the plume being further away from the tracheal wall  433 . In this figure the airflow from the semi-circular outer coaxial tube  405  will redirect the liquid aerosol from the inner lumen  403  away from the tracheal wall. 
     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.