as shown in fig2 - 5 , the present drug delivery device is indicated in general by the reference numeral 10 . it includes as its principal components a one - piece generally integral , rigid , transparent body or spacer 11 with an inlet 12 and outlet 13 , a therapeutic agent directing means 14 , and a baffle 15 . an aerosol canister or metered dose inhaler 16 containing a therapeutic agent such as a bronchodilator or steroid includes a nozzle 17 which is insertable into the directing means 14 . as shown in fig1 - 2 , the drug delivery device 10 is connectable to a mechanical ventilator 20 . the mechanical ventilator 20 includes an inspiratory line 21 for conveying fluid , which is typically a mixture of oxygen and air , to an intubated patient 22 . an expiratory line 23 conveys such a fluid , along with any fluids generated by the patient 22 or the therapeutic agent , back to the mechanical ventilator 20 . a humidifier 24 is typically connected to the inspiratory line 21 . a water trap or condensate collector 25 and spirometer 26 to measure exhaled volume are typically connected to the expiratory line 23 . the ventilator 20 further includes a check valve to prevent backflow , and the expiratory line 23 further includes an exhalation valve which is closed during inspiration and controlled by air pressure . the mechanical ventilator 20 is a positive pressure ventilator that forces fluid into the lungs 30 of the patient 22 . in contrast , in the 1940 &# 39 ; s and 1950 &# 39 ; s , most ventilators used negative pressure ( vacuum ) to inflate the lungs . the body , except for the head , was enclosed in a gas tight chamber and a seal was placed around the neck . a motor driven bellows caused large pressure changes in the chamber , in turn causing pressure changes against the body . since the patient &# 39 ; s airway was outside the chamber , air moved in and out of the lungs . this was the iron lung . some are still used . a modified version which encloses only the chest is called the cuirass ventilator . the vast majority of today &# 39 ; s machines are positive pressure ventilators . in other words , the gas mixture is driven into the chest under positive pressure , through some sort of artificial airway such as a tracheostomy tube , which is inserted through an incision in the neck , or an endotracheal tube 32 passed through either the nose or the mouth and into the trachea . an inflatable cuff 33 at the end of the tube 32 seals against the trachea to prevent gas under pressure from escaping around the tube and back up the airway . the inspiratory phase of the ventilator 20 may be delivered in several different ways : ( i ) a desired volume of gas is set on a dial or touch pad . an upper pressure limit is also set . if the pressure is reached before the set volume is delivered , gas flow stops . the ventilator then resets itself for the next breath and sounds an alarm that signals that the pressure limit was reached . this is referred to as &# 34 ; volume cycle , pressure limited &# 34 ; ventilation ; ( ii ) a desired pressure may be set as the primary cycling mechanism . this leaves the volume variable to changes in position , lung compliance , etc . this is referred to as pressure cycling ; and ( iii ) the third method of delivering the inspiratory phase is referred to as timed cycling and is related to the flow rate of the gas being delivered during inspiration . the shorter the time , the greater the flow , and vice versa , if the volume is constant . ( i ) a timing device in the ventilator causes each breath to be delivered . for example , for a rate of 12 breaths per minute , the machine would delivery a breath every five seconds . a rate of 10 breaths per minute would result in a breath every six seconds ; or ( ii ) the ventilator can be set to be sensitive to the patient &# 39 ; s own inspiratory efforts ( if present ). in this system , whenever the patient attempts to take a breath on his own , the machine responds by delivering a breath of the set volume . usually a minimum number of breaths per minute is set , so if a patient &# 39 ; s respiratory rate falls below that value or stops all together , the machine will assume a pattern according to that value . this is referred to as &# 34 ; assist / control &# 34 ; and is the most common form of ventilation . most positive pressure ventilators allow exhalation to occur passively . a valve , either in the tubing circuit or in the machine , opens when inspiration stops . this causes a release of the pressure built up during inspiration , and gas flows out of the lungs . the spacer 11 includes a rigid frustoconical spacing portion 40 which tapers toward the outlet 13 and which includes larger and smaller diametrical ends 40 . 1 and 40 . 2 . the frustoconical portion 40 includes an inner surface 41 and interior 42 . substantially all of the diametrical sectional slices of the spacing portion 40 have diameters greater than the diameter of the outlet 13 and inspiratory line 21 to allow expansion of the drug bolus . one reason for the frustoconical feature of portion 40 is to simulate or reflect the conical spray pattern of the aerosol therapeutic agent . another reason for the frustoconical shape of portion 40 is to facilitate connection to the inspiratory port of the parallel wye connection 43 . still another reason for the frustoconical shape is to enhance washout of the therapeutic agent and eliminate stagnant areas that otherwise may trap moisture or particles of the therapeutic agent . the frustoconical portion 40 is integrally connected via an annular rib 45 to a tapering portion 46 which tapers toward and is integrally connected to the inlet 12 . the tapering portion 46 encompasses the baffle 15 which directs fluid in a direction oblique of the direction of fluid flowing through the inlet 12 and toward the inner surface 41 of the frustoconical portion 40 . the baffle 15 includes an inner cone - like portion or first deflector 47 running substantially parallel to the tapering portion 46 to form an oblique passage 47 . 1 . the first deflector 47 is frustoconical in shape and tapers toward and is integrally connected to an apertured disc or second deflector 48 with a set of three apertures 49 which permit fluid flow into the interior 42 directly from the inlet 12 . a greater or lesser number of apertures of larger or smaller size may be formed in the disc 48 . an undulating band or third deflector 50 secures the disc 48 and inner cone - like portion 47 to the tapering portion 46 . the undulating band 50 includes respective proximal and distal semicircular recesses 51 , 52 alternating about its circumference to allow fluid flow into the oblique passage 47 . 1 and into the interior 42 . it should be noted that the drug delivery device 10 may be used without the baffle 15 , but use of the baffle 15 is typically preferable . the inlet 12 is tubular and typically is inserted inside the inspiratory line 21 . the outlet 13 is also tubular and typically is inserted over the inspiratory port of the parallel wye connection 43 . it should be noted that the drug delivery device 10 is connectable to all types of wye connections such as bifurcated wyes , f - wyes and swivel wyes . the therapeutic agent directing means 14 is fixed in and to the outlet 13 . the directing means 14 includes a cylindrical retainer 55 affixed to the outer surface of the outlet 13 to stably receive the aerosol canister 16 and to provide an abutment means which prevents a tipping of the aerosol canister 16 when the therapeutic agent is sprayed . a rod - like stem 56 is secured to the cylindrical wall of the outlet 13 and extends into the outlet 13 . the stem 56 is disposed axially relative to the cylindrical retainer 55 and includes a passage 57 . at its upper end , the passage 57 includes a nozzle receiving portion 58 for receiving the nozzle 17 of the aerosol canister 16 . the nozzle receiving portion 58 is formed in part by an annular shoulder or stop 59 for bearing against the end 60 of the nozzle 17 . at the annular shoulder 59 , the passage portion 58 communicates with a passage portion 61 . both passage portions 58 , 61 are formed axially in the rod - like stem 56 . passage portion 61 communicates with an outlet passage portion 62 . passage portion 62 shares a common axis with inlet 12 , outlet 13 and frustoconical portion 40 such that the therapeutic agent is sprayed uniformly into the conical portion 40 . as the end 60 of the nozzle 17 bears on the annular shoulder 59 and pressure is brought to bear on the aerosol canister 16 such that the canister 16 is pushed closer to the cylindrical wall of the outlet 13 , the nozzle 17 is forced into the aerosol canister 16 to trigger the release of the therapeutic agent . an aerosolized therapeutic agent is thereby sprayed through passage portions 61 , 62 and in a conical pattern into the interior 42 of the frustoconical portion 40 . in operation , when the patient 22 requires a therapeutic agent such a bronchodilator or steroid , the inspiratory line 21 is disconnected from the parallel wye connection 43 . the inlet 12 of the device 10 is then connected substantially horizontally in the inspiratory line 21 and the outlet 13 of the device 10 is slipped over the inspiratory port of the parallel wye connection 43 . the aerosol canister 16 and its nozzle 17 are then inserted in the cylindrical retainer 55 and nozzle receiving portion 58 , respectfully . immediately before the inspiratory phase or fluid as designated by the letter a is delivered by the mechanical ventilator 20 , the therapeutic agent is sprayed into the spacer 11 , as designated by the letter b . after the therapeutic agent has formed a cone - like pattern or bolus in the spacer 11 , air or oxygen conveyed by the ventilator 20 enters the inlet 12 and subsequently passes into the interior 42 of the spacer 11 via the apertures 49 and oblique passage 47 . 1 . the fluid thus conveyed mixes with the aerosolized medication to evaporate the liquid carrier and create particles of medication . the fluid thus conveyed also impinges on the bolus from numerous directions to direct the bolus as an intact whole into the lungs . moreover , such fluid flowing through the passage 47 . 1 and apertures 49 creates some turbulence in the interior 42 . such turbulence also contributes to a greater mixing . accordingly , a lesser amount of therapeutic agent is lost to impaction , particle size may be reduced , and a greater amount of agent is delivered out of the outlet 13 and into the lungs 30 . after the desired amount of therapeutic agent is delivered , the drug delivery device 10 is disconnected from the inspiratory line 21 which is reconnected to the parallel wye connection 43 . one of the reasons for the disconnection of the drug delivery device 10 from the inspiratory line 21 is to maintain a relatively bacteria free environment . fluid delivered by the mechanical ventilator 20 is typically warmed and moistened by the humidifier 24 and such moisture tends to cling to surfaces and collect in the inspiratory line 21 and other devices connected in line with the inspiratory line 21 . these moist warm areas may nurture the growth of bacteria . since the present invention is designed to be removed between uses and allowed to dry , the danger of biocontamination is reduced if not eliminated . as shown in fig6 and 7 , an alternate embodiment of the invention includes valved tubular extensions 70 , 71 for being connected to the inlet 12 and outlet 13 , respectively . when the extensions 70 , 71 are connected as such , the drug delivery device 10 is in its preferred form for the delivery of bronchodilators or steroids to the intubated , spontaneously breathing patient who may self - administer or be assisted with administration of the therapeutic agent or to the nonintubated , spontaneously breathing patient who typically self - administers the drug . however , the drug delivery device 10 may be used by the nonintubated , spontaneously breathing patient without the valved extensions 70 , 71 and wherein the outlet 13 serves as a mouthpiece . as shown in fig6 extension 70 includes an inlet 72 and an outlet 73 . outlet 73 slides over the inlet 12 of the drug delivery device 10 . a one - way inlet valve 70 . 1 includes an apertured disc 74 with an axial post 75 secured in the extension 70 between the inlet 72 and the outlet 73 . a flexible disc 76 distorts on the post 75 and is drawn away from the apertured disc 74 when fluid is drawn from the inlet 72 to the outlet 73 to thereby allow fluid flow through the apertured disc 74 . the flexible disc 76 is pushed against the aperture disc 74 when fluid flows from the outlet 73 to the inlet 72 , such as when a patient exhales to prevent fluid flow through the aperture disc 74 and valve 70 . 1 . as shown in fig7 extension 71 includes an inlet 82 , an outlet 83 and a mouthpiece 84 . the outlet 83 includes a one - way exhaust valve 71 . 1 comprising an apertured disc 85 and a post 86 . the apertured disc 85 is secured in the outlet 83 . a flexible disc 87 rides on the post 86 and is drawn against the aperture disc 85 when fluid flows from the inlet 82 to the mouthpiece 84 such as when a patient inhales , to thereby prevent fluid flow through the outlet 83 . when a patient exhales and fluid pressure builds in the drug delivery device 10 and between the inlet 82 and mouthpiece 84 , the flexible disc 87 is pushed away from the aperture disc 85 and fluid flows from the valve 71 . 1 through the outlet 83 . in operation , the patient slips the extensions 70 , 71 over the respective inlet 12 and outlet 13 of the drug delivery device 10 . the aerosol canister 16 and nozzle 17 are then inserted into the cylindrical retainer 55 and nozzle receiving portion 58 . the patient places his or her mouth over the mouthpiece 84 and exhales such that fluid flows through the outlet 83 . immediately before inhaling , the therapeutic agent in the aerosol canister 16 is sprayed into the spacer 11 . as the patient then inhales , air is drawn through the valve 70 . 1 and is drawn into the interior 42 of the spacer 11 via the apertures 49 and oblique flow passage 47 . 1 . as the therapeutic agent fans out into a cone - like pattern , air drawn through the oblique flow passage 47 . 1 minimizes impaction on the inner surface 41 . mixing is enhanced and some turbulence is created as air flowing through the apertures 49 and oblique passage 47 . 1 flows against the spray direction of the therapeutic agent . as well as contributing to a greater mixing of air and therapeutic agent , these factors contribute to reduction of particle size of the therapeutic agent . as the patient continues to inhale , the therapeutic agent and air mixture is drawn through the mouthpiece 84 and into the lungs . the patient may then remove the drug delivery device 10 and mouthpiece 84 from his or her mouth to exhale , or exhale into the mouthpiece 84 to exhaust air through the outlet 83 and valve 71 . 1 . as shown in fig8 - 10 , alternate embodiments of the invention include cylindrical spacers 90 , 91 , 92 . spacer 90 includes rounded ends 95 adjacent to an inlet 96 and an outlet 97 . spacer 90 also includes an apertured baffle similar to baffle 15 with the exception that the baffle in spacer 90 includes a rounded deflector wall 99 instead of a frustoconical wall portion 47 . spacer 90 further includes a cylindrical retainer 100 set in the spacer 90 for the aerosol canister 16 as shown in fig4 and 8 , it should be noted that the height of each of the retainers 55 , 100 is at least as great as the width of each of the respective retainers 55 , 100 . as shown in fig9 spacer 91 includes an inlet 105 and an outlet 106 . the outlet 106 houses the therapeutic agent directing means 14 . as shown in fig1 , spacer 92 includes an inlet 110 , an outlet 111 with the inlet 110 housing the therapeutic agent directing means 14 . in this embodiment , therapeutic agent is sprayed in the direction of fluid flow , although such a spray direction is less preferred . as shown in fig1 , the spacer 11 may be utilized with a nebulizer 115 . in such a use , one port of a t - fitting 116 is slipped onto the inlet 12 of the spacer 11 and the one way exhaust valved extension 71 is slipped onto the outlet 13 . the one way inlet valved extension 70 is slipped onto the other linear port of the t - fitting 116 and the nebulizer 115 is inserted into the remaining port of the t - fitting 116 . the nebulizer 115 includes liquid medication 117 which is drawn through a tube 118 by oxygen or air being passed by and creating a low pressure over the outlet of the tube 118 . the oxygen or air is conveyed by tube 119 running from a compressed gas source and connecting to the exterior of the nebulizer 115 . from tube 119 , the oxygen or air flows into internal tube 120 which has an outlet adjacent the outlet tube 118 . fluid flowing from the internal tube 120 creates the low pressure over the outlet of outlet tube 118 and atomizes the liquid mediation drawn up through the tube 118 to an aerosolized form . in operation , a nonintubated patient exhales and then places his or her mouth on the mouthpiece 84 to inhale medication generated by the nebulizer 115 . during inhalation , air is drawn in through the one - way inlet valve 70 . 1 and the aerosolized medication created by the atomizing tubes 118 , 120 is drawn from the spacer 11 via the t - fitting 116 . as the air and medication is drawn into the spacer 11 , the medication and air are mixed by the baffle 15 before being inhaled into the lungs . such mixing dries the aerosolized medication and thereby reduces particle size of the medication for a more effective therapeutic treatment . an intubated patient may have the device attached to the endotracheal or tracheostomy tube . it should be noted that the spacer 11 may be opaque or translucent . the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof ; therefore , the illustrated embodiment should be considered in all respects as illustrative and not restrictive , reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention .
a spacer for delivering a maximum amount of a therapeutic agent to the lungs . the spacer may be connected in the inspiratory line running from a mechanical ventilator or hand held and operated manually by the nonintubated , spontaneously breathing patient or the intubated , spontaneously breathing patient . the spacer includes the following features to maximize dispersion of the agent into the fluid flow : a structure for spraying the therapeutic agent in a retrograde fashion to prevent loss of the therapeutic agent to the expiratory limb of the respiratory circuit ; a frustoconical shape that reflects the cone - like pattern of an aerosol spray to minimize impaction of the sprayed agent on the inner surfaces of the spacer ; and a baffle to readily mix the fluid with the therapeutic agent and deflect fluid flow along the inner walls of the spacer where the therapeutic agent may otherwise collect .