Abstract:
A method of treating a patient with a pulmonary disease, where the method includes delivering a dose of aerosolized medicament intermittently to a ventilator circuit coupled to the respiratory system of the patient. Also, a method of treating a patient with a pulmonary disease, where the method includes taking the patient off a ventilator, and administering to the patient, a nebulized aerosol comprising from about 100 μg to about 500 mg of a medicament. Additionally, an aerosolized medicament for the treatment of a pulmonary disease, where the medicament includes amikacin mixed with an aqueous solution having an adjusted pH from about 5.5 to about 6.3. The pH is adjusted by adding hydrochloric acid and sodium hydroxide to the aqueous solution.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 10/345,875, filed Jan. 15, 2003, now U.S. Pat. No. 6,968,840, issued Nov. 29, 2005, the entire contents of which are herein incorporated by reference for all purposes. 
     The present application is related to U.S. patent application No. 09/876,542, filed Jun. 7, 2001, now abandoned, Ser. No. 09/876,402, filed Jun. 7, 2001, now abandoned, and 09/812,987, filed Mar. 20, 2001, now U.S. Pat. No. 6,948,491, issued Sep. 27, 2005, the complete disclosures of which are incorporated herein by reference. 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 09/849,194, filed May 4, 2001, now U.S. Pat. No. 6,615,824, issued Sep. 9, 2003, which claims the benefit of Ireland patent application No. PCT/IE/00051, filed May 5, 2000, which are incorporated herein by reference in their entirety. 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 09/812,755, filed Mar. 20, 2001, now U.S. Pat. No. 7,100,600, issued Sep. 5, 2006, which is incorporated herein in its entirety. 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 10/284,068, filed Oct. 30, 2002, now U.S. Pat. No. 7,600,511, issued Oct. 13, 2009, which claims the benefit of U.S. Provisional Application Nos. 60/344,484, filed Nov. 1, 2001 and 60/381,830, filed May 20, 2002, which are incorporated herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to systems and methods for the delivery of aerosolized medicaments. More specifically, embodiments of the invention relate to the coupling of aerosol generators with ventilator circuits, permitting an aerosolized medicament to be inhaled directly by a patient. 
     BACKGROUND OF THE INVENTION 
     Aerosolized medicaments are used to treat patients suffering from a variety of respiratory ailments. Medicaments can be delivered directly to the lungs by having the patient inhale the aerosol through a tube and/or mouthpiece coupled to the aerosol generator. By inhaling the aerosolized medicament, the patient can quickly receive a dose of medicament that is concentrated at the treatment site (e.g., the bronchial passages and lungs of the patient). Generally, this is a more effective and efficient method of treating respiratory ailments than first administering a medicament through the patient&#39;s circulatory system (e.g., intravenous injection). However, may problems still exist with the delivery of aerosolized medicaments. 
     Patients who cannot breathe normally without the aid of a ventilator may only be able to receive aerosolized medicaments through a ventilator circuit. The aerosol generator should therefore be adapted to deliver an aerosol through the ventilator. Unfortunately, medicament delivery efficiencies for combination nebulizer-ventilator systems are quite low, often dropping below 20%. The ventilator circuits typically force the aerosol to travel through a number of valves, conduits, and filters before reaching the patient&#39;s mouth or nose, and all the surfaces and obstacles provide a lot of opportunity for aerosol particles to condense back into the liquid phase. 
     One problem is that conventional aerosolizing technology is not well suited for incorporation into ventilator circuits. Conventional jet and ultrasonic neublizers normally require 50 to 100 milliseconds to introduce the aerosolized medicament into the circuit. They also tend to produce aerosols with large mean droplet sizes and poor aerodynamic qualities that make the droplets more likely to form condensates on the walls and surfaces of the circuit. 
     Delivery efficiencies can also suffer when aerosols are being delivered as the patient exhales into the ventilator. Conventional nebulizers deliver constant flows of aerosol into the ventilator circuit, and the aerosol can linger, or even escape from the circuit when the patient is not inhaling. The lingering aerosol is more likely to condense in the system, and eventually be forced out of the circuit without imparting any benefit to the patient. 
     The failure of substantial amounts of an aerosolized medicament to reach a patient can be problematic for several reasons. First, the dosage of drug actually inhaled by the patient may be significantly inaccurate because the amount of medication the patient actually receives into the patient&#39;s respiratory system may vary with fluctuations of the patient&#39;s breathing pattern. Further, a significant amount of drug that is aerosolized may end up being wasted, and certain medications are quite costly, thus health-care costs are escalated. 
     Some of the unused medication may also escape into the surrounding atmosphere. This can end up medicating individuals in proximity to the patient, putting them at risk for adverse health effects. In a hospital environment, these individuals may be health-care providers, who could be exposed to such air pollution over a prolonged period of time, or other patients, who may be in a weakened condition or otherwise sensitive to exposure to unprescribed medications, or an overdose of a medication. 
     For these reasons, it&#39;s desirable to increase the aerosol delivery efficiencies of nebulizer-ventilator systems. Embodiments of the present invention address these and other problems with conventional systems and methods of treating patients with aerosolized medicaments. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides devices and methods for improving a level of safety to the patient and for providing an increased efficiency of delivery of an aerosol to the patient. 
     Embodiments of the invention include a method of treating a patient with a pulmonary disease. The method includes delivering a dose of aerosolized medicament intermittently to a ventilator circuit coupled to the respirator system of the patient. 
     Embodiments of the invention also include a method of treating a patient with a pulmonary disease by administering to the patient, through a ventilator circuit, a nebulized aerosol comprising from about 100 μg to about 500 mg of a medicament. The efficiency of the method is such that at least 40% of the nebulized aerosol is delivered to the patient. 
     Embodiments of the invention also include a method of treating a patient with a pulmonary disease by taking the patient off a ventilator, and administering to the patient, a nebulized aerosol comprising from about 100 μg to about 500 mg of a medicament. 
     Embodiments of the invention still further include methods of treating a pulmonary disease by administering to a patient a medicament comprising an antibiotic dissolved in an aqueous solution comprising sodium chloride that is adjusted to a pH between 5.5 and 6.3. The medicament is administered by nebulization using a vibratable member with apertures, the member configured to produce 70% or more of aerosol particles with mass mean aerodynamic diameters from about 1 μm to about 7 μm. 
     Embodiments of the invention additionally include a method of treating a patient with a pulmonary disease by administrating an aerosolized medicament to the patient, and administrating, intravenously, a second medicament to the patient that also treats the pulmonary disease. 
     Embodiments of the invention yet still further include an aerosolized medicament for the treatment of a pulmonary disease. The medicament includes amikacin mixed with an aqueous solution having an adjusted pH from about 5.5 to about 6.3. The pH is adjusted by adding hydrochloric acid and sodium hydroxide to the aqueous solution. 
     Embodiments also include methods of nebulizing a liquid. The method comprises taking one or more breaths and measuring characteristics of the breath. Another breath is taken and an aerosol generator is operated based on the measured characteristics of the one or more measured breaths. 
     Still further embodiments of the invention include methods of providing a nebulizer system comprising a housing, an aerosol generator, a controller coupled to the aerosol generator, and a reservoir in communication with the aerosol generator. 
     In still more embodiments, the present invention provides a nebulizer system comprising a housing that defines a passageway that is adapted to deliver an aerosolized liquid to a user. An aerosol generator is positioned to provide an aerosolized liquid into the passageway. A controller having a memory and a plurality of aerosol generator operation programs that control operation of the aerosol generator is coupled to the aerosol generator. 
     In yet still more embodiments, the present invention provides a nebulizing element positioned to provide nebulized fluid into a ventilator breathing circuit to provide nebulized fluid to a patient receiving air from a ventilator. It will be appreciated that a nebulizing element may also be referred to herein an aerosolization element, and a ventilator may also be referred to herein as a respirator. 
     Embodiments of the invention also provide operation sequences by which aerosol is provided a predetermined points in a breath cycle provided by a ventilator. In one aspect, the present invention provides for an operation sequence in which aerosol production begins at a predetermined point within an inhalation phase, which may also be referred to herein as an inspiratory phase, and stops at a second predetermined point within the same inhalation phase. In another aspect, the present invention provides for an operation sequence, which may be referred to as an operation program, in which aerosol production begins at a predetermined point in an inhalation phase and stops at a point after the inhalation phase has ended, i.e. at a certain point in the exhalation phase. It will be appreciated that the exhalation phase may also be referred to as the expiratory phase, and may encompass the entire period of time during which no inhalation phase is taking place; in other words, the exhalation phase may include not only the actual exhalation of the patient, but also any pause that may occur before or after exhalation. In another aspect, the present invention provides an operation sequence in which aerosolization begins at a predetermined point within the exhalation phase and stops within that exhalation phase, or, alternatively, begins at a predetermined point within an exhalation phase and stops at a predetermined point in the succeeding inhalation phase. 
     Embodiments of the invention also provide for selection of a particular operating sequence from a plurality of available operating sequences. Similarly, the present invention provides for modes of operation, which modes may include one or more operating sequences. 
     Embodiments additionally provide for algorithms to set forth operation sequences, choice of operation sequences or choice of modes of operation. 
     Embodiments also provide for consideration of the identity of a drug to be administered in executing an algorithm, choosing a mode of operation, or selecting or running an operation sequence. 
     Embodiments of the invention also provide for nebulization of particular drug groups or drugs, such as, for example, antibodies, such as IgG or antibiotics, such as aminoglycosides, such as amikacin. 
     Embodiments still further provide for a nebulized droplet ejection device for use with a ventilator, wherein the device produces droplets by a vibratory apertured element during a selected interval of a breathing cycle. 
     Embodiments additionally provide for apparatus and methods for varying the particle size distribution of a nebulized mist by varying the aperture exit diameter of an apertured vibratory aerosolization element. 
     Additional embodiments and features are set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the specification or may be learned by the practice of the invention. The features and advantages of the invention may be realized and attained by means of the instrumentalities, combinations, and methods described in the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates components of a pulmonary drug delivery system according to embodiments of the invention; 
         FIG. 1B  shows an embodiment of a junction device that can be used in a pulmonary drug delivery system according to embodiments of the invention; 
         FIG. 2  shows an on-ventilator configuration of a pulmonary drug delivery system according to embodiments of the invention; 
         FIG. 3  is a schematic perspective view of a nebulizer incorporated into a ventilator breathing circuit in accordance with the present invention; 
         FIGS. 4A-D  show off-ventilator configurations of pulmonary drug delivery systems according to embodiments of the invention; 
         FIG. 5  shows a nebulizer coupled to T-piece adaptor for a ventilator circuit according to embodiments of the invention; 
         FIG. 6  shows an exploded view of a nebulizer according to embodiments of the invention; 
         FIG. 7  is a schematic cross-sectional representation of an aerosol generator in accordance with the present invention; 
         FIG. 8  is a schematic cutaway cross-section detail of the aerosol generator represented in  FIG. 6A ; 
         FIG. 9  shows an exploded view of a nebulizer coupled to a filter according to embodiments of the invention; 
         FIGS. 10A-B  show the flow of gases and medicaments through a nebulizer-filter system according to embodiments of the invention; 
         FIGS. 11A-B  show the flow of gases through a chamber and filter according to embodiments of the invention; 
         FIGS. 12A-C  show graphs of various modes of aerosolization over the course of breathing cycles; 
         FIG. 13  illustrates a simplified method of the present invention; 
         FIG. 14  is a schematic representation of algorithms of operating sequences in accordance with the present invention; 
         FIG. 15  is an alternative schematic representation of the algorithms of operating sequences of  FIG. 14 ; 
         FIG. 16  is a further schematic representation of algorithms of operating sequences shown in  FIG. 15 , and in accordance with the present invention; and 
         FIG. 17  is a schematic representation of an algorithm by which an operating sequence may be chosen base on the combination of a plurality of independent sets of information. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Overview 
     As noted above, conventional nebulizer-ventilator systems have low medicament delivery efficiency (e.g., less than 20%). Embodiments of the invention include methods and systems for increasing delivery efficiencies to at least 40%, and in many instances to about 70% or more. The increased efficiency for delivering the aerosolized medicament may be attributable, in part, to one or more features that may be implemented in embodiments of the invention. These features include synchronizing the generation of aerosol with an inspiratory phase of the ventilator cycle (e.g., phasic delivery). The features may also include supplying air (e.g., an “air chaser”) following aerosol generation, which can clear the endotracheal tube and reduce the amount of medicament exhaled by the patient. Features may further include connecting the aerosol generating unit directly to the hub of the endotrcheal tube that is connected to the patient. Still other features include generating aerosolized medicament with smaller particle sizes (e.g., about 1 to 5 μm average diameter). Additional features may also include storing the medicament in a conical shaped reservoir to minimize the residual medicament volume. 
     Embodiments of the systems are configurable to administer aerosolized medicament to a patient both on-ventilator and off-ventilator. On-ventilator treatment methods include administering the nebulized aerosol through a ventilator circuit to the patient. Aerosol doses, containing about 1 to about 500 mg of a medicament, may be delivered through the ventilator circuit in a phasic or non-phasic manner. Off-ventilator treatment methods may include taking the patient off the ventilator before administering the nebulized aerosol. Once the treatment session is completed the patient may be put back on the ventilator, or may breathe on his or her own without assistance. 
     Embodiments of the invention provide treatments for a variety of ailments using a variety of aerosolizable medicaments. The ailments may include pulmonary ailments such as ventilator-associated pneumonia, hospital-acquired pneumonia, cystic fibrosis, mycobacterial infection, bronchitis, staph infection, fungal infections, viral infections, protozal infections, and acute exacerbation of Chronic Obstructive Pulmonary Disease, among others. The aerosolizable medicaments used to treat the ailments may include antibiotics, anti-oxidants, bronchodialators, corticosteroids, leukotrienes, protease inhibitors, and surfactants, among other medicaments. 
     Exemplary Pulmonary Drug Delivery Systems 
       FIG. 1A  shows an embodiment of a pulmonary drug delivery system (“PDDS”)  100  according to the invention. The PDDS  100  may include a nebulizer  102  (also called an aerosolizer), which aerosolizes a liquid medicament stored in reservoir  104 . The aerosol exiting nebulizer  102  may first enter the T-adaptor  106  that couples the nebulizer  102  to the ventilator circuit. The T-adaptor  106  is also coupled to the circuit wye  108  that has branching ventilator limbs  110  and  112 . 
     Coupled to one of the ventilator limbs  110  or  112  may be an air pressure feedback unit  114 , which equalizes the pressure in the limb with the air pressure feedback tubing  116  connected to the control module  118 . In the embodiment shown, feedback unit  114  has a female connection end (e.g., an ISO 22 mm female fitting) operable to receive ventilator limb  112 , and a male connection end (e.g., an ISO 22 mm male fitting) facing opposite, and operable to be inserted into the ventilator. The feedback unit may also be operable to receive a filter  115  that can trap particulates and bacteria attempting to travel between the ventilator circuit and tubing  116 . 
     The control module  118  may monitor the pressure in the ventilator limb via tubing  116 , and use the information to control the nebulizer  102  through system cable  120 . In other embodiments (not shown) the control module  118  may control aerosol generation by transmitting wireless signals to a wireless control module on the nebulizer  102 . 
     During the inhalation phase of the patient&#39;s breathing cycle, aerosolized medicament entering T-adaptor  106  may be mixed with the respiratory gases from the inspiratory ventilator limb  112  flowing to the patient&#39;s nose and/or lungs. In the embodiment shown, the aerosol and respiratory gases flow through nose piece  122  and into the nasal passages of the patient&#39;s respiratory tract. 
     Other embodiments of the circuit wye  108  shown in  FIG. 1A  are also contemplated in embodiments of the invention. For example, an alternate embodiment of the wye  108  is illustrated in  FIG. 1B , which shows junction device  135 , which may be configured downstream from nebulizer  102 . In the downstream configuration, gas flow  150  containing aerosolized medicament enters the junction device  135  at first end  143  and exits at second end  144  of the respiratory circuit. The junction device  135  includes a tubular main body member  141  having a straight longitudinal lumen  142  connecting the opening in a first end  143  attachable to inspiratory tube  112  and an opening in a second end  144  attachable to a patient interface, such as nose piece  122 . Junction device  135  may further comprise a tubular branch member  145  having a lumen  146  that communicates with lumen  142  at intermediate opening  147 . Gas flow  150  contains aerosol particles of medicament emitted by nebulizer  102  that pass from inspiratory tube  112  into lumen  142  through the opening in first end  143 . 
     In contrast to a “Y”-shaped junction device, junction device  135  provides for gas flow  150  (containing aerosolized medicament) to follow a straight unobstructed path through the respiratory circuit without any portion being diverted into branch member  145 . In other words, there is virtually no change in the angle of the path of gas flow  150 . As a result, the full amount of aerosol particles of medicament contained in gas flow  150  is efficiently delivered through the respiratory circuit to the patient. Upon expiratory effort by the patient, expiratory gas flow  152  follows a path through lumen  142  to lumen  146  of branch member  145  and through expiratory tube  110  back to the ventilator (not shown). 
       FIG. 2  shows another embodiment of a PDDS  200 , where nose piece  122  has been replaced by ET tube  222 . In this embodiment, during inhalation the aerosolized medicament generated by nebulizer  202  is carried by the flow of respiratory gases through the ET tube  222  and into the patient&#39;s bronchial passages and lungs. 
     Referring to  FIG. 3 , a nebulizer  85 , which may have a top portion  93  through which liquid may be provided may be incorporated into a ventilator breathing circuit of a ventilated patient. The breathing circuit may comprise a “Y” connector  88 , which may in turn have an inlet portion  89 , an endotracheal tube portion  90  and an outlet portion  91 . The inlet portion  89  carries air provided from the ventilator  92  toward the patient. The endotracheal tube portion  90  of the Y connector  88  carries the incoming air to the patient&#39;s respiratory tract; this direction is represented by arrow “a”. The endotracheal tube portion  90  also carries the patient&#39;s exhalation to the outlet portion  91  of the Y connector  88 , and the outlet portion may lead to an exhaust, represented by arrow “b”, to remove the patient&#39;s exhalation from the system. The nebulizer  85  of the present invention aerosolization element generates an aerosol cloud  94  that remains substantially within the inlet portion  89  of the Y connector  88  when there is no inspiratory air flowing through the inlet portion, by virtue of the aerosolization element, as described above, producing a low velocity mist. In this manner, aerosol that is generated when there is no inhalation air being provided will not be carried out through the outlet portion  91  of the Y connector and lost to the ambient environment. Accordingly, a dose of aerosolized medication may be preloaded, i.e., produced and placed substantially within the inlet portion  89  prior to an inhalation phase being sent by the ventilator  92 . In this manner, such medication can be swept into a patient&#39;s respiratory system at the very start of the inhalation cycle. This may be of particular benefit in the case of neonatal patients and in other instances in which only the initial blast of inhalation phase will reach the target portion of the respiratory system. In alternate embodiments, the ventilator may generate a continuous bias flow of gas through the ventilator circuit. The bias flow may push some of the aerosolized medicament through the outlet portion  91 , but there is still an overall benefit from having the aerosolized medicament preloaded through the ventilator circuit. 
     PDDS systems like the ones described above in  FIGS. 1-3  may include equipment for phasic delivery of aerosolized medicaments. This equipment may include breathing characteristics sensors, which can monitor the breathing characteristics of a patient using the PDDS. The sensors can send breathing characteristic information to the PDDS controller to allow the controller to select an appropriate delivery cycle of the aerosolized liquid to the patient. Typically, breathing characteristic sensors can be used to measure a breathing pattern of the patient, the peak flow, breathing rate, exhalation parameters, regularity of breathing, and the like. Such measured breathing characteristics data be delivered to controller by analog or digital signals, and run through a software algorithm to determine an appropriate sequence of delivery relative to the measured breathing cycle to the patient. 
     For example, one exemplary breathing characteristic that may be sensed by a sensor is the cycle of a ventilator providing air to a patient; for example, the start of an inhalation cycle generated by the ventilator. The sensor may also sense other parameters, for example, it may be an acoustic sensor that is activated through passing the respiratory flow of the patient through an acoustic chamber so as to produce an acoustic tone, which is proportional to the inspiratory flow rate. The frequency of the acoustic tone indicates the inspiratory flow rate at any instant of the breathing cycle. The acoustic signal can be detected by the controller such that integration of the flow rate with time produces the tidal volume. Both the flow rate and the tidal volume can then be used by the controller to determine when the aerosol generator generates the droplets and at what mass flow rate such that maximum deposition of droplets is obtained. Further, the acoustic tone may be recorded to produce a record of the breathing pattern of the patient which may be stored in the microprocessor. This information can be later used to synchronize the ejection of droplets for the same patient. Such information may also be later employed for other diagnostic purposes. A more complete description of such sensors are described in commonly owned, U.S. Pat. No. 5,758,637, which was previously incorporated by reference. 
     In some embodiments, the sensors can be used to monitor the breathing characteristics of the patient throughout the delivery regime so as to ensure that the aerosol is efficiently delivered throughout the aerosolization procedure. In such embodiments, the controller can adjust the aerosol delivery based on any measured change in the breathing pattern of the patient during the aerosolization. With this monitoring and adjustment predetermined times for the beginning and ending of aerosolization can be reset based on the actual breathing of the patent. In other embodiments, however, the breathing sensor can be used to determine the breathing cycle of a tidal breath and to choose the appropriate preprogrammed delivery cycle that is stored in the memory of the controller. In other embodiments, the controller may be configured to provide aerosol based on the time. For example, the controller may be configured to start aerosol production at the beginning of an inhalation phase of a breathing cycle and stop at a point at which a predetermined percentage of the inhalation has taken place. Alternatively, the controller may be configured to start aerosolization at a first point at which a first predetermined percentage has taken place, and stop aerosolization at a second point at which a second predetermined percentage of that inhalation has taken place. Alternatively, aerosol may begin during an inhalation phase and end during the subsequent exhalation phase. Alternatively, the controller may be configured to begin aerosol production at a certain point during exhalation and stop during that exhalation or during the subsequent inhalation. Thus, embodiments of the PDDS may include a nebulizer having an aerosol generator and a controller configured to have the controller begin aerosolization during exhalation and stop during that exhalation or in the subsequent inhalation. In still other embodiments, the controller may be configured to begin aerosol production at a start point in the breathing cycle, and continue to generate aerosol for a set period of time regardless of how a patient&#39;s breathing cycle varies. At the end of the time period, aerosol generation stops until the next start point is in the breathing cycle. In further embodiments, the controller may be configured to start and stop aerosol production for preprogrammed periods of time that are independent of the patient&#39;s breathing cycle. 
     The controller may be operable to allow for a choice of modes of operation, for example, a mode in which aerosolization begins once a certain breath characteristic is detected, such as a sufficient level of inhalation, and ends when there is no longer a sufficient level; another mode in which aerosolization begins once a certain breath characteristic is detected, such as a sufficient level of inhalation, and ends at a predetermined time within the inhalation cycle, such as for example, before the level of inhalation falls below that required for operation of an aerosolization element, or, alternatively, at any other point within the inhalation cycle, such as after the inhalation phase of the cycle before exhalation has begun, or after exhalation has begun. 
     The level of inhalation may be sensed by a pressure sensor. Such a transducer may monitor a drop in air pressure or a rise in air pressure within a chamber that is in fluid communication with the ventilator circuit. In this manner, a pressure drop may be sensed by a patient inhaling through the circuit, for example, in an instance in which the ventilator provides assisted ventilation initiated by a patient&#39;s commencement of an inhalation. Similarly, a pressure rise may be sensed in an instance in which the ventilator pushes inhalation air to the patient without the patient initiating a breath. Another mode in which the controller may be operable is a mode in which the on/off operation of the aerosol generator is triggered by time, which may be ascertained from an internal clock device, such as a clock built into a microprocessor, or from an external source. Another mode in which the controller may be operable is in which the on/off operation of the aerosol is triggered by the controller receiving an external signal, such as a signal from a ventilator, which can correspond to the point in the ventilator&#39;s cycle of that is the start of an inhalation phase in which the ventilator begins to push inspiratory air into the ventilator circuit. The controller may be operable between such modes, including a mode in which the aerosolization begins at a predetermined time in the breathing cycle and ends at a predetermined time in the breathing cycle. The first and second predetermined times in the third mode may be during inhalation. Alternatively, the first and second predetermined times may be during exhalation, or at the first predetermined time may be during exhalation and the second predetermined time may be during subsequent inhalation. These times may correspond to certain percentages of the inhalation phase taking place, or any other points of reference within a breathing cycle. 
     Alternatively, the first predetermined time and the second predetermined time may be designated as any point within a single breathing cycle, or alternatively, the first predetermined point may be at any point within one breathing cycle and the second predetermined point may be at any point in a subsequent breathing cycle. The controller may make the determination of when to begin, and operate to begin aerosolization, and may make the determination of when to stop aerosolization to stop, and cause aerosolization to stop. The controller may make such determinations and take such actions based on accessing stored algorithms. The controller may receive a signal from the ventilator that establishes a reference point, nonetheless the controller, by making the determinations an taking the actions based on stored algorithms, and/or information obtained as to the identity of a drug to be administered, may cause aerosol production to begin and/or end independent of the instantaneous position of the ventilator with respect to the ventilator cycle. 
     Embodiments also include a controller operable to allow for a single mode of operation, where the single mode of operation may be any mode, including but not limited to the modes described above. For example, a mode in which aerosolization begins once a certain breath characteristic is detected, such as a sufficient level of inhalation, and ends when there is no longer a sufficient level. Similarly, the controller may operable in a mode in which aerosolization begins once a certain breath characteristic is detected, such as a sufficient level of inhalation, and ends at a predetermined time within the inhalation before there is no longer a sufficient level or an aerosolization element. 
     Alternatively, the mode may be a mode in which the aerosolization is commenced based on a signal from the ventilator indicating the attainment of a certain point within the ventilation output cycle or the inhalation cycle of the patient. (The ventilation output cycle of the ventilator may coincide with the inhalation cycle of the patient, such that the ventilation output phase of the ventilator output cycle and the inhalation phase of the inspiratory cycle of the patient occur substantially simultaneously. Such may be the case where a patient is completely passive and the only inhalation that occurs is by generation of air from the ventilator during the output phase of the ventilator cycle.). Such point may be during the output phase of the output cycle of the ventilator or during the inhalation phase of the inhalation cycle of the patient. The predetermined point can be chosen to coincide with a certain level of output from the ventilator or at a certain point in time during the ventilator output cycle. Such a predetermined point may be a specific point within the output phase of the ventilator cycle, or, a specific point within the non-output phase of the ventilator cycle, based, for example, on the timing of the previous or succeeding output phase of the ventilator. In another aspect, the present invention provides for a ventilator along with the aerosol generator and controller. In an aspect of the invention, a predetermined time may be based on the timing of a ventilator supplying air to a user. In this manner, the controller may be set to work off of the timing of the ventilator in one mode, while working off the patient&#39;s inspiratory effort in another mode, or mode that allows for a combination of the patient&#39;s inspiratory effort and the timing of the ventilator, for example, where the ventilator is set to assist the patient by supplying air upon the patient&#39;s effort or where the patient has not made a sufficient effort within a predetermined period of time. 
     Exemplary Off-Ventilator Configurations 
     Referring now to  FIGS. 4A-D  embodiments of off-ventilator configurations of a PDDS are shown. In  FIG. 4A , the off-ventilator PDDS  400  includes an endpiece  402  that is coupled to a nebulizer  404  and wye  406 . The nebulizer  404  may include reservoir  408 , which supplies the liquid medicament that is aerosolized into connector  410 . The connector  410  can provide a conduit for the aerosolized medicament and gases to travel from the wye  406  to endpiece  402 , and then into the patient&#39;s mouth and/or nose. The first wye limb  412  may be connected to a pump or source of pressurized respiratory gases (not shown), which flow through the wye limb  412  to the endpiece  402 . A one-way valve  413  may also be placed in the limb  412  to prevent respired gases from flowing back into the pump or gas source. The limb  412  may also include a pressure feedback port  414  that may be connected to a gas pressure feedback unit (not shown). In the embodiment shown, a feedback filter  416  may be coupled between the port  414  and feedback unit. 
     The off-ventilator PDDS  400  may also include a second wye limb  420 , which includes a filter  422  and one-way valve  424 , through which gases may pass during an exhalation cycle. The filter  422  may filter out aerosolized medicament and infectious agents exhaled by the patient to prevent these materials from escaping into the surrounding atmosphere. The one-way valve  424  can prevent ambient air from flowing back into the PDDS  400 . 
       FIG. 4B  shows another embodiment of an off-ventilator PDDS  450 , where the endpiece is replaced by mouthpiece  452 , operable to sealingly engage the lips of a patient. The mouthpiece  452  may be removablely attached to the rest of the off-ventilator PDDS  450  by a connector  454  that is coupled to T-piece  456 . The connector  454  may be made from an elastomeric material (e.g., rubber, silocone, etc.) that can resiliently couple the mouthpiece  452  to the T-piece  456 . In the embodiment shown, the PDDS  450  also includes a gas inlet port  458  that can be sealingly coupled to an additional gas source (not shown), such as oxygen, on an inspiratory limb  460  of wye  462 . 
       FIG. 4C  shows still another embodiment of an off-ventilator PDDS  470 , where the endpiece is replaced by a facemask  472 , operable to sealingly encompass the nose and mouth of a patient. The facemask  472  may have a coupling end, which can resiliently couple the facemask to the rest of the PDDS  470 . The coupling end may be continuous with the rest of facemask  472  to form a single piece. 
       FIG. 4D  shows yet another embodiment of an off-ventilator PDDS  490 , where the endpiece, T-piece, and wye form a single continuous piece  492 . A gas inlet may be contiguously formed in the piece  492  to connect a gas source, such as oxygen. A nebulizer inlet to removably receive a nebulizer may also be formed in piece  492 . In addition, a filter  496  and one-way valve  498  may be coupled to a branched end of the piece  492 . Another branched end of piece  492  may also be coupled to a one-way valve  499 , operable to prevent gases from back flowing into a pump or other pressurized gas source (not shown) coupled to the branched end. 
     The on and off-ventilator configurations of the PDDS allow continuity of treatment as the patient switches between on-vent and off-vent treatment configurations. In both configurations, a patient is able to receive the same aerosolized medicament at the same dosage level, providing a continuity of treatment as the patient transitions from on-ventilator care to off-ventilator care. This can be particularly useful for extended treatment regimens, when the patient receives the aerosolized medicament for several days or weeks. 
     Exemplary Nebulizers 
     In regard to the nebulizers (i.e., aerosol generators), they may be of the type, for example, where a vibratable member is vibrated at ultrasonic frequencies to produce liquid droplets. Some specific, non-limiting examples of technologies for producing fine liquid droplets is by supplying liquid to an aperture plate having a plurality of tapered apertures and vibrating the aperture plate to eject liquid droplets through the apertures. Such techniques are described generally in U.S. Pat. Nos. 5,164,740; 5,938,117; 5,586,550; 5,758,637, 6,014,970, and 6,085,740, the complete disclosures of which are incorporated by reference. However, it should be appreciated that the present invention is not limited for use only with such devices. 
     Referring now to  FIG. 5 , a nebulizer  502  coupled to a T-piece  504  is shown. The nebulizer  502  may include a reservoir  506  that is orientated at a non-perpendicular angle to the T-piece  504 . For example, the reservoir  506  may be formed at an angle between about 10° and about 75° with respect to an axis that is collinear with the base conduit of the T-piece  504 . The reservoir  506  may have a cap  508  that can sealingly engage an opening in the reservoir  506  to contain a liquid medicament  509  in the reservoir body  510 . The cap  508  and top of the reservoir  506  may have conjugate threads or grooves that can be sealingly engaged to close the reservoir. Alternatively, the cap  508  may be made from an elastomeric material that can be elastomerically sealed or snapped into place around the opening in the reservoir  506 . The reservoir  506  may be refilled by removing cap  508 , adding liquid medicament to the reservoir body  510 , and resealing the cap  508  on the reservoir  506 . In the embodiment shown, about 4 mL of medicament may be stored in the reservoir body  510 . In additional embodiments, the volume of medicament stored may range from about 1 mL to about 10 mL, and larger reservoirs may hold 10 mL or more of a medicament. 
     The nebulizer  502  may also include a power inlet  512  that can receive a plug  514  that supplies electric power to the nebulizer. Alternatively, the power inlet  512  may be replaced or supplemented by a power cord that terminates with a plug that can be plugged into a power source (not shown). The inlet  512  may also receive an electronic control signal that can control the timing and frequency which the nebulizer aerosolizes medicament from the reservoir  506 . 
       FIG. 6  shows an exploded view of a nebulizer  600  decoupled from the T-piece (not shown), according to an embodiment of the invention. An opening  602  in the nebulizer  600  that couples to the T-piece, or some other inlet in the PDDS, may include an aerosolization element  604  secured within the opening  602  by retaining element  606 . In operation, medicament from the reservoir  608  passes through outlet  610  and is aerosolized by the aerosolization element  604 . The aerosolized medicament may then drift or flow past retaining element  606  and into the PDDS. Alternative embodiments, not shown, may have the aerosolization element  604  permanently affixed, or integral to, the opening  602 , and retaining element  606  may be absent. 
     The aerosolization element  604  may have a vibratable member that moves with respect to an aperture plate to aerosolized the liquid medicament. By utilizing an aerosol generator that produces aerosol by the electric powering of the vibratable member that causes the aperture plate to eject liquid at one face thereof, through its apertures, as a mist from the other face thereof, as generally described above (and as described generally in U.S. Pat. Nos. 5,164,740; 5,938,117; 5,586,550; 5,758,637, 6,085,740; and 6,235,177, the complete disclosures of which are, and have been above, incorporated herein by reference), the starting and stopping of aerosol generation may be controlled on the level of accuracy of microseconds or milliseconds, thus providing accurate dosing. The timing of aerosol generation can be done based solely on a predetermined timing within a breathing cycle, on timing in conjunction with the length of a prior breath or portions thereof, on other breathing characteristics, on particular medication being administered, or a combination of any of these criteria. 
     The aerosolization element may be constructed of a variety of materials, comprising metals, which may be electroformed to create apertures as the element is formed, as described, for example, in U.S. Pat. No. 6,235,177 assigned to the present assignee and incorporated by reference herein in its entirety. Palladium is believed to be of particular usefulness in producing an electroformed, multi-apertured aerosolization element, as well as in operation thereof to aerosolize liquids. Other metals that can be used are palladium alloys, such as PdNi, with, for example, 80 percent palladium and 20% nickel. Other metals and materials may be used without departing from the present invention. 
     Referring now to  FIGS. 7 and 8 , an aerosolization element  70  may be configured to have a curvature, as in a dome shape, which may be spherical, parabolic or any other curvature. The aerosolization element may be formed to have a dome portion  73  over its majority, and this may be concentric with the center of the aerosolization element, thus leaving a portion of the aerosolization element that is a substantially planar peripheral ring portion  75 . The aerosolization element has a first face  71 , a second face  72 . As shown in  FIG. 8 , the aerosolization element may also have a plurality of apertures  74  therethrough. The first face  71  may comprise the concave side of the dome portion  72  and the second face  72  may comprise the convex side of the dome portion  72  of the aerosolization element  70 . The apertures may be tapered to have a narrow portion  76  at the first face  71  and a wide portion  78  at the second face  72  of the aerosolization element  70 . Typically, a liquid will be placed at the first face of the aerosolization element, where it can be drawn into the narrow portion  76  of the apertures  74  and emitted as an aerosolized mist or cloud  79  from the wide portion  78  of the apertures  74  at the second face  72  of the aerosolization element  70 . 
     The aerosolization element may be mounted on an aerosol actuator  80 , which defines an aperture  81  therethrough. This may be done in such a manner that the dome portion of the aerosolization element protrudes through the aperture  81  of the aerosol actuator  80  and the substantially planar peripheral ring portion  74 , on the second face  72  of the aerosolization element  70  abuts a first face  82  of the aerosol actuator  80 . A vibratory element  84  may be provided, and may be mounted on the first face  82  of the aerosol actuator  80 , or alternatively may be mounted on an opposing second face  83  of the aerosol actuator  80 . The aerosolization element may be vibrated in such a manner as to draw liquid through the apertures  74  of the aerosolization element  70  from the first face to the second face, where the liquid is expelled from the apertures as a nebulized mist. The aerosolization element may be vibrated by a vibratory element  84 , which may be a piezoelectric element. The vibratory element may be mounted to the aerosol actuator, such that vibration of the vibratory element may be mechanically transferred through the aerosol actuator to the aerosolization element. The vibratory element may be annular, and may surround the aperture of the aerosol actuator, for example, in a coaxial arrangement. 
     Embodiments of the invention include the aerosolization element, or the aerosol generator, comprising the aerosolization element  70 , the aerosol actuator  80  and the vibratory element  86  may be replaced with a respective assembly that has apertures of a different size, such as a different exit diameter, to produce a mist having a different aerosol particle size. A circuitry  86  may provide power from a power source. The circuitry may include a switch that may be operable to vibrate the vibratory element and thus the aerosolization element, and aerosolization performed in this manner may be achieved within milliseconds of operation of the switch. The circuitry may include a controller  87 , for example, a microprocessor that can provide power to the vibratory element  84  to produce aerosol from the aerosolization element  70  within milliseconds or fractions of milliseconds of a signal to do so. For example, aerosol production may begin within about 0.02 to about 50 milliseconds of such a signal and may stop within about 0.02 to about 50 milliseconds from the cessation of a first signal or a second signal either of which may act as a trigger to turn of aerosolization. Similarly, aerosol production may begin and end within about 0.02 milliseconds to about 20 milliseconds of such respective signaling. Likewise, aerosol production may begin and end within about 0.02 milliseconds to about 2 milliseconds of such respective signaling. Further, this manner of aerosolization provides full aerosolization with a substantially uniform particle size of low velocity mist  79  being produced effectively instantaneously with operation of the switch. 
     The switch, described above, may be operable by a pressure transducer, which may be positioned in the mouthpiece of the nebulizer. The pressure transducer may be in electrical communication with the circuitry, and a microprocessor may also be in electrical communication with the circuitry, and the microprocessor may interpret electrical signals from the pressure transducer, and may also operate the switch to begin aerosolization. In this manner, nebulization can begin substantially instantaneously with the inhalation of a user upon the mouthpiece. An example of such a sensor switch can be found in co-assigned U.S. application Ser. No. 09/705,063 presently abandoned, assigned to the present assignee, the entire content of which is hereby incorporated herein by reference. 
     Another transducer may be used to sense the absence or presence of liquid in the reservoir, by sensing, for example, a difference between vibration characteristics of the aerosolization element, such as, for example, differences in frequency or amplitude, between wet vibration and substantially dry vibration. In this manner, the circuitry, may, for example by way of the microprocessor, turn the vibration off when there is essentially no more liquid to aerosolize, i.e., when the end of the dose has been achieved, thus minimizing operation of the aerosolization element in a dry state. Likewise, the switch may prevent vibration prior to delivery of a subsequent dose into the reservoir. An example of such a switch is shown in co- assigned U.S. application Ser. No. 09/805,498, now U.S. Pat. No. 6,546,927, issued Apr. 15, 2003, the entire content of which is hereby incorporated herein by reference. 
     Exemplary Nebulizer-Filter Configurations 
       FIG. 9  shows an exploded view of a nebulizer  902  coupled to a filter  904  according to embodiments of the invention. This configuration of the nebulizer  902  and filter  904  may be part of an off-ventilator apparatus for delivering aerosolized medicament to the patient. The filter  904  may be sandwiched between a first holding element  906 , which has a nebulizer port  908  to accept the nebulizer  902 , and a second holding element  910 , which has a port  912  to accept a mouthpiece, facemask, nose plugs, etc. The first holding element  906  may have one or more openings that permit filtered gases passing through filter  904  to escape into the surrounding environment. Element  906  may also have gas inlet  914  that can sealingly engage with a compressed respiratory gas source (e.g., oxygen, air, etc.) or pump (not shown). The second holding element  910  may have a pressure port  916  that can sealingly engage with a pressure sensor (not shown) that measures the gas pressure in the apparatus. 
       FIGS. 10A-B  show the above-described nebulizer-filter configuration in operation during the inhalation ( FIG. 10A ) and exhalation ( FIG. 10B ) phases of a patient&#39;s breathing cycle. During inhalation, pressurized gas passes through gas inlet  914  and filter  904  into an area where the gases are mixed with aerosolized medicament generated by nebulizer  902 . The aerosol and gas mixture then flow through port  912  and into the patient&#39;s lungs. In the exhalation phase, gases respired by the patient enter the apparatus through port  912  and exit through the openings in holding element  906  after being filtered through the filter  904 . 
     The pressure in the apparatus may be monitored throughout the breathing cycle with a pressure sensor coupled to pressure port  916 . The pressure sensor (not shown) may generate an analog or digital electronic signal containing information about the pressure level in the apparatus. This signal may be used to control the amount of aerosolized medicament and/or gases entering the apparatus over the course of the patient&#39;s breathing cycle. For example, when the pressure in the apparatus decreases as the patient inhales, the pressure signal may cause the nebulizer  902  to add aerosolized medicament to the apparatus, and/or cause the gas source or pump to add gas through inlet  914 . Then, when the pressure in the apparatus increases as the patient exhales, the pressure signal may cause the nebulizer  902  to stop adding aerosolized medicament to the apparatus, and/or cause the gas source or pump to stop adding gas through inlet  914 . Controlling the aerosol and/or gas flow based on the patient&#39;s breathing cycle, i.e., phasic delivery of the gases and aerosols, will be described in additional detail below. 
     Exemplary Aerosol Chamber 
     Embodiments of the invention may include a chamber  1102  that can hold gas and aerosol mixtures for delivery to the patient&#39;s lungs. The chamber may be used in both on-ventilator and off-ventilator configurations. The expanded volume within the chamber reduces the surface area to volume ratio at the patient interface end of the system, which can increase the aerosol delivery efficiency.  FIGS. 11A-B  show an embodiment of such a chamber, with flow paths for gases and aerosols being inhaled and exhaled by a patient. The chamber  1102  may include a plurality of ports, including a gas inlet port  1104  that can receive gases from a ventilator, pump, and/or compressed gas source (e.g., a tank of compressed air, oxygen, etc.). The chamber  1102  may also include a second port  1106  that can receive a nebulizer (not shown), and a third port  1108  that can receive an endpiece (e.g., a mouthpiece, facemask, etc.). 
     Port  1108  may include a valve  1110  that can change the fluid flow path through the port  1108  depending on phase of a patient&#39;s breathing cycle. For example, during an inhalation phase ( FIG. 11A ), valve  1100  may be pushed away from the chamber  1102 , channeling the gases and aerosols to flow around the ends of the valve into the endpiece (not shown), and ultimately into the patient&#39;s lungs. Then, during an exhalation phase ( FIG. 11B ), the valve  1110  is pushed by the patient&#39;s respiring gases to close port  1108 , forcing the gases through openings  1112  and filters  1116  before exiting the filter housing  1117  into the surrounding atmosphere. The filter housing  117  may include perforations that allow exhaled gases to exit and/or be constructed from gas permeable materials through which exhaled gas may diffuse. 
     Exemplary Medicaments 
     Embodiments of the invention contemplate a variety of medicaments that can be aerosolized and delivered to a patient&#39;s lungs. These medicaments may include antibiotics such as aminoglycosides, β-lactams, and quinolines, among others. The aminoglycosides may include amikacin, gentamycin, kanamycin, streptomycin, neomycin, netilmicin, and tobramycin, among other aminoglycosides. Other medicaments may also be used, including anti-oxidants, bronchodilators, corticosteroids, leukotrienes, prostacyclins, protease inhibitors, and surfactants, among other medicaments. Table 1 lists classes of medicaments and some of the ailments they may be used to treat in their aerosolized state. 
                                       TABLE 1                   Classes of Aerosolizable Medicaments            Medicament           Duration of       Class   Aliments Treated   Dosing   Treatment               Anti-oxidants   RDS, Prevention of   1-4 per day   Duration of           BPD, ALI, ARDS       ventilation       Bronchodilators   Asthma, COPD,   1-4 per day   As needed           ARDS, RDS               Corticosteroids   Asthma, COPD, BPD   1-2 per day   Duration of                   ventilation       Leukotrienes or   Immunodeficiency,   1-4 per day   5-14 days       related agonists   COPD, Treatment/                   prevention of pneumonia                   or RSV infection               Prostacyclin or   PPHN, Secondary   Continuous   TBD       related analogues   pulmonary hypertension,                   Post-cardiac                   surgery, ARDS               Protease   AECOPD, ARDS,   1-2 per day   5-14 days       inhibitors   RDS, BPD               Surfactants   RDS, Prevention of   1-2 per day   TBD           BPD, ARDS               AECOPD: acute exacerbation of COPD       ALI: Acute lung injury       ARDS: Acute respiratory distress syndrome       BPD: Bronchopulmonary dysplasia       COPD: chronic obstructive pulmonary disease       PPHN: persistent pulmonary hypertension       RDS: Respiratory distress syndrome (also known as infant respiratory distress syndrome)       RSV: Respiratory syncytial virus            
Exemplary Phasic Delivery Methods
 
       FIGS. 12A-C  show graphs of various modes of aerosolization over the course of breathing cycles.  FIG. 12A  shows a continuous aerosolization mode where aerosolized medicament is generated a constant rate throughout the breathing cycle. Continuous (i.e., aphasic) generation modes typically have about 10% to about 15% aerosol delivery efficiency.  FIG. 12B  shows a phasic delivery mode where aerosolized medicament is administered for substantially all of the inhalation phase of the breathing cycle. These modes typically have about 15% to about 25% efficiency.  FIG. 12C  shows another phasic delivery mode where the aerosolized medicament is administered during a predetermined portion of the inhalation phase beginning, for example, at the onset of inhalation. It has been discovered that these modes typically have delivery efficiencies between about 60% to about 80%, by weight, of the total amount of medicament that is aerosolized. 
     Embodiments of the invention take advantage of this discovery by controlling delivery to a predetermined percentage of the breathing cycle, such as a predetermined percentage of the inhalation phase of the breathing cycle, to provide greater delivery efficiency than either continuous delivery or delivery during the entire inhalation phase. Embodiments of the invention also take advantage of the surprising discovery that the percentage of increase in efficiency in delivery for such a predetermined portion of the inhalation phase over delivery during the entire inhalation phase is itself greater than the increase in efficiency of delivery during the inhalation phase compared to aphasic administration of the aerosol. 
     Phasic delivery methods may include measuring the characteristics of a patient&#39;s inhaled breath, typically a tidal breath, and using the measurements to control the operation of the aerosol generator.  FIG. 13  provides a simplified flowchart that illustrates some of the steps for phasic delivery of an aerosolized medicament according to embodiments of the invention. Phasic delivery methods may include having a patient can take one or more breaths  1320 , and measuring the characteristics of the breath  1322 . The breathing characteristics that can be measured include, but are not limited to, a breathing pattern, peak inspiratory flow rate, breathing rate, exhalation parameters, regularity of breathing, tidal volume, and the like and can estimate a user&#39;s tidal volume based on such information. 
     The user can take another tidal breath and the aerosol generator can be operated based on the measured characteristics of the tidal breath  1324 . It should be appreciated however, that instead of a tidal breath, the person can take other types of breath. Alternatively, the controller may base the timing of operation of the aerosol generator so that aerosol is generated at specific time periods within a breathing cycle. For example, the controller may operate the aerosol generator for the first  50  percent of inspiration. Alternatively, the controller may operate the aerosol generator to generate aerosol after a portion of inhalation has taken place and to cease producing aerosol after another portion of inhalation has taken place. For example, the controller may cause aerosol to be generated beginning after 20% of the inspiration has taken place and cause aerosol production to cease after 70% of inspiration has taken place. The controller may cause aerosol production to start after, for example, after 90% of exhalation has taken place and, for example, cause aerosol production to stop after 30% of the following inspiration has taken place. By controlling the specific timing within the breathing cycle that aerosolized medication is provided into the breathing circuit, greater efficiency of drug administration can be achieved. 
     Since some of the pharmaceuticals to be aerosolized may be more effective when delivered near the beginning of a patient&#39;s breathing cycle, while other pharmaceuticals may be more effective when delivered near the end of the patient&#39;s breathing cycle, the timing of the aerosol generation depends on the type of medicament delivered. If it is known what type of medication or drug is being delivered, the controller can select the best time during the patient&#39;s breathing cycle to deliver the aerosol, based upon a predetermined regimen for that drug that is stored in memory. As an additional benefit, an estimate of the patient&#39;s age and/or distress can be made, for example, by measuring the tidal volume and breathing rate. Such measurements can influence the efficiency requirements of the dose per breath. These or other variables can be used in establishing various regimes for aerosol delivery, in particular delivery into the breathing circuit of a ventilator. These regimes can be stored in memory and then accessed by the controller as appropriate for a given patient condition. 
     For example, for a bronchodilator the best time to delivery may be half way through the inhalation phase of a breath when impaction would be reduced since inhalation flows are reducing. For steroids, it may be best to deliver towards the end of the inhalation phase of a breath. For antibiotics, it may be best to slightly pre-load, e.g., deliver aerosol during the exhalation phase, or deliver right at the start of the breath. For example, antibiotics may be delivered at the beginning of a ventilator provided inhalation, and the aerosol delivery may stop after a predetermined percentage of the inhalation has been provided. One class of antibiotics that may be administered in accordance with the present invention is the class known as the aminoglycoside class of antibiotics. This class of antibiotics has typically been administered intravenously, however, such delivery can sometimes have unwanted side effects, which may be systemic. Embodiments of the invention provide for the administration of antibiotics, such as aminoglycosides including amikacin by delivering them in aerosolized form into the breathing circuit of a patient on a ventilator. In this manner, amikacin can be used to treat pulmonary infection conditions that typically arise when patients are mechanically ventilated, and the amikacin, or other aminoglycoside or other antibiotic, can be delivered directly to the target of treatment, the pulmonary tract, avoiding side effects that may otherwise arise from intravenous administration. Further, because of the great cost of such drugs, far greater efficiency is achieved through this pulmonary delivery. As noted above with reference to  FIG. 12C , delivery of aerosol during a beginning percentage of the inhalation phase of a breathing cycle may yield up between about 60% and about 80% efficiency, a significantly higher efficacy than continuous aerosolization, or aerosolization for an entire inhalation phase of an inhalation cycle. 
     Embodiments of the invention provide for conducting various regimes of aerosolization, depending on the situation. For example, in  FIG. 14 , a selection between a first, second and third regime is shown. A regime may be selected manually or automatically, for example, through the application of an algorithm that selects an operation program based on information that is either input or stored. For manual selection, a user may operate a mechanical switch to select a regime, or may enter such a selection into an electronic input device, such as a keyboard. Alternatively, the controller may automatically choose a regimen, as described above, by matching a drug code on a drug nebule with a library of drug-regimen combinations. (It should be noted that in  FIGS. 14-17 , schematic flow charts of operation sequence algorithms are depicted. Although items therein will be referred to as steps for ease of discussion, they refer more broadly herein to states of operations or modalities in which a system may exist or cycle through. Steps depicted in a rectangle are essentially states of operation, actions or modalities. Steps depicted in diamonds indicate either a selection or the continuance of the previous state of operation, action or modality until a predetermined condition is satisfied. Two successive diamonds refer to satisfaction of a first condition and of a second condition respectively, the second of which may be a subset of the first.) 
     In step  1400 , a choice is made to follow a particular regime. In this case, regime I is a regime in which aerosol is generated continuously (step  1402 ). Regime II provides aerosol generation during the inhalation phase only (step  1404 ). In this case, in step  1406 , aerosol generation is set to start at the start of the inhalation phase and, in step  1408 , aerosol generation is set to stop when the inhalation phase stops. In step  1410 , aerosol generation begins at the start of the inhalation phase. In step  1412 , when the inhalation phase ends, aerosol generation stops (step  1414 ). 
     Regime III provides for inhalation during a predetermined percentage of the inhalation phase (step  1416 ). A predetermined percentage of an inhalation (or exhalation) phase may be based on a measured time from a discrete point in the ventilator cycle, such as the instantaneous commencement of inspiratory air generation by the ventilator. Alternatively, such predetermined percentage may be based on the time interval between successive discrete points in the ventilator, such as successive commencements of successive inhalation air generation by the ventilator. Alternatively, such percentages may be based upon air pressure in the ventilator circuit, or any other parameter. With respect to Regime III, in this case, in step  1418 , a first predetermined point is set to correspond with the completion of a first predetermined percent of the inhalation. In step  1420 , a second predetermined point is set to correspond to a second predetermined percent of inhalation percent being completed. For example, as described above, the first predetermined point may correspond to 20% of the inhalation phase being completed, and the second predetermined point may correspond to a point at which 70% of that same inhalation has taken place. In step  1422 , aerosol generation begins at the first predetermined point in the inhalation phase. In step  1424 , when the second predetermined point is reached, the controller carries out step  1414  and stops the aerosol generation. 
     Similarly, as noted above, other regimes may be followed, for example, in which aerosol generation begins during the inhalation phase and ends during the exhalation phase, or begins during exhalation and ends during that exhalation, or begins during exhalation and ends in the subsequent breath cycle, for example, at a predetermined point in the subsequent inhalation phase. Accordingly, turning to  FIG. 15 , a selection may be made, at step  1430 , between regimes II (step  1432 ) and III (step  1434 ) as described above, and another regime, regime IV (steps  1436 - 1442 ), which is also available for selection. In regime IV, aerosol generation may begin at a first predetermined point (step  1436 ), and this first predetermined point may be after a predetermined percentage of the inhalation phase has taken place, or it may be a predetermined point after the inhalation phase has been completed. For example, this point may be a predetermined point after a predetermined percent of the exhalation phase has taken place, or may be a predetermined point prior to the start of the subsequent inhalation phase. Aerosol generation may stop during exhalation (regime IVa, step  1438 ), at the completion of exhalation (regime IVb, step  1440 ), or aerosol generation may continue into the next breath cycle (regime IVc, step  1442 ), and stop, for example, after a predetermined point during the subsequent inhalation phase. 
     In this example, with the controller having a selection choice between operation sequences corresponding to regimes II, III and IV, schematic representation of the operation sequences are shown in  FIG. 16 . In step  1450 , a regime is selected. In step  1452 , the aerosol generator controller selects an operation sequence based on selected regime. In step  1454 , the controller receives a signal indicating that ventilator has begun to supply an inhalation phase. The signal, as described above, may be a signal provided directly by the ventilator. Alternatively, the signal may be provided by a sensor, and such sensor may sense the commencement of an inhalation phase provided by the ventilator, as described above, by sensing a pressure change in the breathing circuit. In step  1456 , the controller carries out selected operation sequence. In the case of regime II (step  1458 ), the controller turns on aerosol generator upon commencement of inhalation phase provided by the ventilator. The controller continues to operate the aerosol generator until a point at which the inhalation phase completed (step  1460 ). In step  1462 , controller turns off aerosol generator. 
     In the case of regime III, the controller does not take any action to begin aerosol generation, until a predetermined point in the inhalation phase, corresponding to a percentage of the inhalation phase being completed (step  1464 ). In step  1466 , at a predetermined point in the inhalation phase, the controller turns on aerosol generator. In step  1468 , aerosol generation continues until a second predetermined point inhalation phase, corresponding to a second percentage point of completion of the inhalation phase. At this point, the controller carries out step  1462  and turns off aerosol generator. With respect to regime IV, aerosol generation begins after a predetermined point of completion of the inhalation phase (step  1464 ) and this point may be predetermined to occur after the inhalation phase has been completed and the exhalation phase has begun (step  1470 ). In step  1472 , the controller turns the aerosol generator on to begin aerosolization. Variations can be made as to the point at which the aerosol generation is turned off. If it is desired that aerosol generation be completed before the completion of the exhalation phase (regime Iva), then aerosol generation may continue until a predetermined point prior to the subsequent inhalation (step  1476 ). Alternatively, it may be desirable to continue aerosolization until the end of exhalation, which may correspond to the point of commencement of the subsequent inhalation, as in regime IVb (step  1478 ). Alternatively, it may be desired to follow a regimen such as regime IVc, where aerosol generation continues through into the subsequent breath cycle (step  1480 ), until, for example, a predetermined percent of the subsequent inhalation phase has been completed (step  1482 ). In these regimes, aerosolization will continue until the satisfaction of these conditions (step  1476  for regime IVa, step  1478  for regime IVb or step  1482  for regime IVc), at which point the controller carries out step  1462  and stops the aerosol generator. The process may continue with the next signal indicating that the ventilator has begun to provide an inhalation phase, step  1454 . 
     Further, the choice of which operating sequence to follow may rely at least in part on the identity of a drug to be administered, which information can be considered by the controller as described above. In addition, it should be appreciated that modifications may be made to these examples without departing from the present invention. For example, a system may be configured, or a method may be carried out, to be able to select more than three initial regimes to follow. For example, regimes I, II, III and IV as described above may be simultaneously selectable. Further, various steps may be altered; for example, some steps may not be discrete steps. Thus, step  1456  may not be a discrete step but rather the following of an operation sequence according to a selected regime. Similarly, the order of the steps may be changed, such as the controller may select an operating sequence (step  1452 ) after receiving a signal that the ventilator has commenced to provide an inhalation phase (step  1454 ). Steps may also be combined, such as, for example, in regime IV steps  1464  and  1470  may be combined as a single step, as these two steps represent successive criteria for the determining a single first predetermined point has been met. Likewise, step  1474  may be combined with steps  1476 ,  1478  or  1480 , as step  1474  is the predicate for the condition test specified in each of the other successive tests, steps  1476 ,  1478  or  1480 . The algorithm examples may be altered to form other operating sequences. For example, an operating sequence may call for the controller to start aerosol generation at the start of the inhalation cycle provided by the nebulizer, as in regime II, at step  1458 , and turn off the aerosol generator at a point at which a predetermined percentage of the inhalation phase has been completed, as in regime III, step  1468  (and step  1462 ). In a similar manner, other criteria may be used to trigger the turning on or off of the aerosol generator. For example, as described above, the start of aerosolization may be triggered by the sensing of a particular pressure or change in pressure in the ventilator circuit, and may end by following the turning off sequence of regimes III (steps  1468  and  1462 ) or IV (steps  1474 ,  1476 ,  1478  or  1480  and  1482 , followed by step  1462 , as described above. 
       FIG. 17  is a schematic representation of an algorithm by which an operating sequence, for providing nebulized drug to a patient receiving air from a ventilator, may be chosen based on the combination of a plurality of independent sets of information, in this case, drug identity and a signal from the ventilator. In step  1700 , a library of drug regimes is provided, the library based on various drugs that may be administered. In step  1702 , the identity of a particular drug is provided to the system, and this may be provided, as described above, by a marker on a nebule containing the drug, the marker being read by the system. In step  1704 , the controller looks up a regime from the library of stored regimes to select a regime based on the particular drug to be administered. In step  1706 , the controller receives a signal from the ventilator. In step  1708 , the controller then chooses an operation sequence based in part on the drug identity and drug regime and in part on the independent information provided by the signal from the ventilator. In step  1710 , the controller carries out the operation sequence, which may be producing aerosol at a predetermined interval in the ventilation cycle based on the drug and the regime provided for the drug factored in with the inhalation cycle of the ventilator. These descriptions are illustrative, and accordingly, the order of the steps may be altered, and other variations, additions and modifications, as described above, may be made still in accordance with the present invention. 
     The phasic delivery methods outlined above may also be practiced with additional systems such as continuous positive airway pressure (“CPAP”) systems, such as the ones described in U.S. patent application Ser. No. 10/828,765, filed Apr. 20, 2004, U.S. patent application Ser. No. 10/883,115, filed Jun. 30, 2004, now U.S. Pat. No. 7,290,541, issued Nov. 6, 2007, and U.S. patent application Ser. No. 10/957,321, filed Sep. 30, 2004, now U.S. Pat. No. 7,267,121, issued Sep. 11, 2007, where the entire contents of all the applications are herein incorporated by reference for all purposes. 
     EXPERIMENTAL 
     Delivery efficacy tests were conducted with an on-ventilator PDDS aerosolizing an aqueous solution of amikacin sulfate. The PDDS ventilator circuit configuration was similar to the one shown and described in  FIG. 2  above. A 400 mg dose of the amikacin was run through the PDDS. The PDDS was configured to deliver the aerosolized medicament by a phasic delivery regime similar to the one shown in  FIG. 12C . The medicament dose was delivered over the course of about 50 to about 60 minutes. 
     Table 2 presents efficiency data for the delivery of aerosolized medicament to through systems according to embodiments of the invention. In the experimental setup, aerosolized droplets deposited on an inspiratory filter placed at a patient end interface are weighed and compared to the total weight of the dose of medicament that was aerosolized. The percentage of a dose deposited on the inspiratory filter represents the fraction of the total aerosolized dose that would be inhaled by a patient, and thus quantifies the efficiency of the system. 
     
       
         
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Percent of Dose Deposited on Inspiratory Filter 
               
             
          
           
               
                   
                 Percent 
                   
                   
                   
               
               
                 Run 
                 Deposited on 
                   
                 Standard 
                   
               
               
                 No. 
                 Filter 
                 Mean 
                 Deviation 
                 % RSD 
               
               
                   
               
               
                 1 
                 69% 
                 71% 
                 0.04 
                 6% 
               
               
                 2 
                 75% 
                   
                   
                   
               
               
                 3 
                 75% 
                   
                   
                   
               
               
                 4 
                 77% 
                   
                   
                   
               
               
                 5 
                 69% 
                   
                   
                   
               
               
                 6 
                 66% 
                   
                   
                   
               
               
                 7 
                 68% 
               
               
                   
               
             
          
         
       
     
     Table 2 shows the efficiencies of 7 runs for a system according to an embodiment of the invention had a mean efficiency of 71% ±6%. This efficiency level is well above conventional systems for the delivery of aerosolized medicaments, where the efficiency levels are typically 10% or less. 
     Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. Additionally, a number of well known processes and elements have not been described in order to avoid unnecessarily obscuring the present invention. Accordingly, the above description should not be taken as limiting the scope of the invention. 
     Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included. 
     As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a process” includes a plurality of such processes and reference to “the electrode” includes reference to one or more electrodes and equivalents thereof known to those skilled in the art, and so forth. 
     Also, the words “comprise,” “comprising,” “include,” “including,” and “includes” when used in this specification and in the following claims are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, acts, or groups.