CA2245948C - Nebulizer apparatus and method - Google Patents

Abstract

An apparatus and method for providing a nebula or aerosol to a patient. In one aspect, a nebulizer is pressure sensitive so that nebulization is coordinated with a breathing cycle of the patient. The nebulizer includes a movable gas diverter that diverts pressurized gas across a liquid outlet. The diverter is moved in response to the patient's breathing cycle. In one aspect, a biasing member moves the diverter. According to another aspect of the nebulizer, an annular liquid orifice disperses an aerosol in a radial direction in response to a pressurized gas flow from an orifice located concentrically thereto. Multiple liquid orifices may be provided. In a further aspect of the nebulizer, a reservoir includes an upper, wide portion and a lower narrow portion to apply relatively uniform pressure at a liquid orifice.

Description

WO 97/29799 PCT/CA97/0009b s The present invention relates to a method and 4 apparatus for delivering an aerosol, nebulized liquid s or solid medicine or a vapor to a patient's respiratory s tract, and more particularly, the present invention relates to an improved nebulizer that provides an s aerosol more efficiently and with improved particle s size uniformity.
io Medical nebulizers for generating a fine spray or m nebula of a liquid medicine that can be inhaled by a iz patient are well known devices commonly used for the zs treatment of certain conditions and diseases.
z4 Nebulizers have applications in treatments for zs conscious, spontaneously-breathing patients and for ss controlled ventilated patients.
i~ In some nebulizers, a gas and a liquid are mixed is together and directed against a baffle. As a result, i9 the liquid is aerosolized, that is, the liquid is 2o caused to form into small particles that are suspended z~. in the air. This aerosol of the liquid can then be zz inhaled into a patient's respiratory tract. One way to 2s mix the gas and liquid together in a nebulizer is to 24 pass a quickly moving gas over a liquid orifice tip of zs a tube. The negative pressure created by the flow of zs pressurized gas is a factor that contributes to drawing i the liquid out of the liquid orifice tip into the 2 stream of gas and nebulize it.
_ _ 3 Some of the considerations in the design and 4 operation of nebulizers include regulation of dosages s and maintenance of consistent aerosol particle size.
s In conventional nebulizer design, pressurized gas may entrain a liquid against a baffle on a continuous basis s until the liquid in a reservoir is depleted.
g Continuous nebulization may result in a waste of to aerosol during a patient's exhalation or during a delay il between a patient's inhalation and exhalation. This Za effect may also complicate regulation of dosages Z3 because the amount of wasted aerosol may be difficult 2~ to quantify. Also, continuous nebulization may affect is particle size and/or density. In addition, there may is be excess medication lost to condensation on the i~ nebulizer or mouthpiece during periods of non-i8 inhalation. On the other hand, interrupted ss nebulization may also affect particle size and density 2o as. the nebulization is turned on and off.
21 There are several other considerations that relate 2z to the effectiveness of nebulizer therapies. For a3 example, it has been suggested that nebulization 24 therapy is more effective when the generation of 2s aerosol particles is relatively uniform, for example, 2s producing particles of a particular size, particles 2~ within a range of sizes, and/or particles a substantial Zs percentage of which are within a range of sizes. One as particle size range~that has been considered to be so appropriate for inhalation therapy includes a particle 3i size range of approximately 0.5 to 2 microns. Other 32 particle size ranges may be suitable or preferable for 33 particular applications. Generally, large and small , 34 size droplets should be minimized. It has also been . ss considered desirable for some inhalation therapies that , 3s a substantial percentage, e.g. over 750, of the aerosol s~ particles be less than approximately 5 microns 1 depending on the desired area of particle deposition in 2 the respiratory tract. In addition, it may be s advantageous for a nebulizer to be able to generate a 4 large amount of aerosol quickly and uniformly so that a ~ s proper dosage can be administered.
s Accordingly, with these considerations taken into ~ account, there is a need for an improved nebulizer.
s SUMN~AA~' OF THE INVENTTON
s The present invention provides a method and zo apparatus for delivering nebulized liquid or solid is medication or vapor to a patient. According to one i2 aspect, the present invention includes a nebulizer that z3 generates an aerosol during inhalation, and sometimes i4 during both inhalation and exhalation, and that can be Zs used both by ventilated patients and spontaneously is breathing patients.
17 According to another aspect of the invention, is there is provided a nebulizer that is pressure i9 sensitive so that nebulization is coordinated with a 2o natural physiological cycle of the patient, such as the ai patient's breathing cycle. The nebulizer includes a 22 movable gas diverter that diverts pressurized gas 2a across a liquid outlet. The diverter is moved in 2ø response to the patient's breathing cycle. In one ~s embodiment, a biasing member such as membrane, moves 2s the diverter.
z7 According to still another aspect of the as invention, a nebulizer is provided having an annular 2s liquid orifice that disperses an aerosol in a radial so direction in response to a pressurized gas flow from a 3i gas orifice located concentrically thereto.
32 In yet another aspect of the invention, a 3s nebulizer is provided having a chamber with multiple 34 liquid orifices and/or gas orifices located therein.
35 The multiple orifices may be annular orifices. A

WO 97/29799 PCTlCA97/00096 a. diverter may be provided to direct gas across the 2 multiple liquid orifices.
3 In a further aspect of the invention, a nebulizer reservoir includes an upper, wide portion and a lower s narrow portion to apply relatively uniform pressure at .
6 a liquid orifice that draws liquid from the reservoir.

a Figure 1 is a partial cross-sectional side view of s a ffirst embodiment of a nebulizer according to the to present invention.
m Figure 1A is a cross-sectional view of the z2 nebulizer of Figure 1 shown in an inspiration cycle.
13 Figure 2 is a cross-sectional view of the nozzle 14 assembly of the nebulizer of Figure 1.
is Figure 3 is a cross-sectional top view of the is nebulizer of Figure 1 taken along line 3-3' (without s7 the baffle for clarity) .
is Figure 4 is perspective view of the top portion of Zs the nebulizer of Figure 1.
2o Figure 4A is perspective view of the top of the ai nebulizer shown in the inspiration cycle of Figure 1.A.
2a Figure 5 is a cross sectional view of a second as embodiment of the nebulizer of the present invention.
a4 Figure 6 is a cross sectional view of the bottom 2s of the chimney of the embodiment of Figure 5.
as Figure 7 is a cross sectional view similar to a7 Figure 6 showing an alternative embodiment the bottom 2s of the chimney of the nebulizer shown in Figure 5.
as Figure 8 is a cross-sectional view of a portion of ao the nebulizer of Figure 5 showing the diverter ring.
31 Figure 9 is a cross sectional view similar to 32 Figure 8 showing an alternative embodiment of the 33 diverterring arrangement for the embodiment of the 34 nebulizer of Figure 5.

'WO 97129799 PCTYCA97100096 i Figure 10 is a cross sectional view similar to 2 Figure 8 showing another alternative embodiment of the 3 diverter ring arrangement.
- 4 Figure 11 is a cross sectional view of a third s embodiment of the nebulizer of the present invention.
s Figure 12 is a top view of the embodiment nozzle ~ assembly of Figure 11.
a Figure 13 is a cross sectional view of the s embodiment of Figure 11 taken along line 13-13'.
to Figure 14 is a cross sectional view of a fourth l~. embodiment of the nebulizer of the present invention.
i2 Figure 15 is a cross sectional view of a fifth is embodiment of the nebulizer of the present invention.
14 Figure 16 is a cross sectional view of a sixth is embodiment of the nebulizer of the present invention.
is Figures 17A and 17B shows cross sectional views of 2~ a seventh embodiment of the present invention.
1s DETAILED DESCRIPTION OF THE

2o I. First Embodiment 2s A first preferred embodiment of a nebulizer 10 is 22 illustrated in Figure 1. The nebulizer 10 is a small a3 volume nebulizer and includes a housing or container 12 a4 deffining an internal chamber 14. The housing 12 is 2s formed of a cylindrically-shaped side wall portion 18, 2s a top portion 20, and a bottom portion 22. The 27 . component parts of the housing 12 may be formed of 2a separate, multiple pieces of material that are 29 connected together by welding, adhesives, etc., or more 3o preferably, some of the component parts may be formed 31 together of a single piece of material formed by an 32 injection molding process. For example, the bottom, a3 and side portions 22 and 18 may be formed of separate 34 pieces that are connected together, or preferably, ss these parts may be formed of one piece of molded 3s plastic. Any of a number of plastics may be suitable, including polycarbonate, or polycarbonate blends. A
_ 5 _ s cover 21 is removably mounted on the upper portion of a the housing 12, such as by means of a snap-on cover s arrangement, twist-lock threads, screws or other types g of fasteners. The housing 12 is approximately 6 cm s (2.36 in) in height and has a diameter of approxi_m_ately s 4 cm (1.57 in).
A lower portion 23 of the chamber 14 serves as a , s reservoir for holding a fluid 25 for nebulizing, such as a solution containing a medication. Located in the io lower portion 23 of the housing 12 is a nozzle assembly iz 24. Referring to Figures 1-3, the nozzle assembly 24 i2 extends downward from the chamber 14 of the housing 12 13 to a fitting 28 located external of the chamber 14 on a z4 bottom side 22 of the housing 12. The fitting 28 is is sized to connect to a supply 27 of pressurized gas is provided through conventional tubing 29. The i7 pressurized gas may be supplied by any suitable source, is such as a conventional gas supply used in hospitals, a is pump, compressor, cartridge, canister, etc.
2o The nozzle assembly 24 is comprised of an outer 2i tubular member 30 and an inner tubular member 32. The 22 inner tubular member 32 has a passageway 34 that 2s extends from an opening 36 in the bottom end of the 24 fitting 28 to a gas outlet orifice 38 located at a top 2s end 39 of the nozzle assembly 24. The inner tubular 2s member 32 is located.in an inner passageway 40 of the 2~ outer tubular member 30. The inner tubular member 32 as is sized to slide into the inner passageway 40 of the 2s outer tubular member 30 so that it is aligned therein.
3o A passageway 42 is formed by grooves or slots on. the 3i outer surface of the inner tubular member 32 and/or the 32 inner surface of the outer tubular member 30. The 33 passageway 42 extends from an opening 44 located at the s4 reservoir 23 of the lower portion of the chamber 14 to' ss a liquid outlet orifice 46 located at the top end 39 of ss the nozzle assembly 24. The passageway 42 serves to ' 3~ convey liquid medicine from the reservoir 23 at the i bottom of the chamber 14 to the liquid outlet orifice 2 46 at the top of the nozzle assembly 24. (In an s alternative embodiment, the passageway 42 may be formed 4 by spaces or regions between fins located on the outer s surface of the inner tubular member 32 and/or the inner s surface of the outer tubular member 30.) As shown in Figure 3, the liquid outlet orifice 46 s has an annular shape defined by the top ends of the s outer tubular member 30 and the inner tubular member 32 io of the nozzle assembly 24. The gas outlet orifice 38 m has a circular shape and is located concentrically of is the annular liquid orifice. In one embodiment, the gas is outlet orifice 38 is approximately 0.022 inches in 14 diameter and the liquid outlet orifice 46 has an outer Zs diameter of approximately 0.110 to 0.125 inches and an is inner diameter of approximately 0.084 inches. These i7 dimensions are provided by way of example and the ie nebulizer may be made in other sizes with different is dimensions as desired.
2o The top end 39 of the nozzle assembly 24 is formed 2i by the top ends of the outer and inner tubular members 22 30 and 32. In a present embodiment, the top end 39 is 23 a generally flat surface having a diameter of 24 approximately 0.18 inches. In alternative embodiments, 25 the top end 39 may have an other-than-flat shape, for 2s example, the inner tubular member 32 may be spaced 2~ above the outer tubular member 30 so that the liquid 2s orifice 46 is located below the gas orifice 38.
29 The nozzle assembly 24, or a portion thereof, may 3o be formed as part of the housing 12 as a single piece si of material in an injection molding process. For 32 example, the inner tubular member 32 may be formed of 33 the same piece of injected molded plastic as the bottom ' 34 of the housing 12.
35 Referring again to Figure 1, the nebulizer 10 also ss includes a chimney assembly 50. The chimney assembly 50 is located in an upper portion of the chamber 14 WO 97/Zf799 PCT/CA97/00096 1 above the liquid reservoir 23. The chimney assembly 50 a includes a tubular body 5l that defines an internal 3 passageway 52 that extends from an inlet opening 56 in 4 the housing cover 21 to an outlet opening 58 at a s bottom end of the tubular body 51. Thus, the chimney s assembly 50 serves as an inlet channel for ambient air to enter into the chamber 14. The inlet opening 56 a communicates with ambient air (through ports of an s actuator button, as described below) and the outlet io opening 58 communicates with the chamber ~.4.
iz Located on the lower end of the chimney assembly z2 50 is a diverter 60. The diverter 60 may be formed of 13 the same piece of molded plastic material as the i4 chimney 50 or alternatively, the diverter 60 may be 15 formed of a separate piece of material that is attached is by suitable means to the rest of the chimney assembly z~ 50. (The diverter may also be provided pneumatically, ~.s for example by an opposing gas source located directly is opposite the nozzle.) The diverter 60 is located ao directly opposite from the gas outlet orifice 38 and 2~ the liquid outlet orifice 46 located at the top end 39 as of the nozzle assembly 24. The diverter 60 is movable 23 so that the distance between the diverter 60 and the a4 top surface 39 of the nozzle assembly 24 can be varied.
as The diverter 60 has of a flat circular shape with a 2s diameter of approximately 0.38 inches so that it 2~ extends over both the gas and liquid orifices 38 and 46 as out to approximately the edge of the top surface 39 of 2s the nozzle assembly 24.
so The chimney assembly 50 is connected to the 31 housing 1.2. Specifically, the chimney assembly 50 is sa attached to the top portion 20 of the housing 12 by 3s means of a membrane or diaphragm 64. The membrane 64 s4 is a ring-shaped piece of a flexible, resilient 3s material, such as silicone rubber. An outer rim or ss bead of the membrane 64 is secured in a groove in the s~ top portion 20 of the housing 12 and/or the cover 21.
_ g _ i An inner rim of the membrane 64 is secured in a slot 2 formed by two parts of the chimney assembly 50. The 3 membrane 64 has a rolled cross-sectional profile as 4 shown in Figure 1. This permits the membrane 64 to act s as a rolling diaphragm. The membrane 64 permits s limited movement of the chimney assembly 50. The 7 chimney assembly 50 is connected to the membrane 64 so s that the membrane 64 biases the chimney assembly 50 9 away from the nozzle assembly 24 as shown in Figure 1.
io When installed in the manner shown in Figure l, the ii bottom of the chimney assembly 50 is approximately 0.15 a.2 inches away from the top surface of the nozzle assembly Z3 24.
i4 Located at the top end of the chimney assembly 50 is is an actuator~68. The actuator 68 connects to the is tubular body 51 of the chimney assembly 50 and extends z7 through the opening 56 at the top of the housing 12 in is the cover 21. The actuator 68 includes a closed top is ~ side 70 with one or more side opening ports 72.
2o Referring to Figure 4, located on the sides of the az body of the actuator 68 are indicators 69A and 69B.
22 The indicators 69A and 69B may be formed of colored 2a markings or parallel rings on the sides of the actuator 24 68. In a preferred embodiment, the indicator 69A is 2s red and is located next to the top side 21 of the 2s nebulizer body 12. The indicator 69B is preferably 27 green and is adjacent to and above the indicator 69A.
2s Located in the chamber 14 at the bottom end of the 2s chimney assembly 50 is a bell-shaped baffle 74. The 3o baffle 74 extends from the opening 58 at the bottom of 31 the chimney passageway 51 outward toward the inside 32 wall of the cylindrical portion 18 of the housing 12.
33 The baffle 74 includes a horizontal portion 75 and a s4 vertical portion 76 that extends downward from the 35 horizontal portion 75 toward the top of the nozzle ss assembly 24. The baffle 74 has an open bottom side g _ i providing an air passageway around the bottom side of 2 the cylindrical vertical wall 76.
s As mentioned above, the diverter 60 is movable 4- relative to the nozzle assembly 24. The present s embodiment provides a means to limit the travel of the , s diverter relative to the nozzle assembly 24. This may 7 be accomplished in any of several suitable ways. In a , s present embodiment, the movement of the diverter 60 s toward the nozzle assembly 24 is limited by one or more io stop pins 80. The stop pins 80 extend up from the ss bottom portion 22 of the housing. In a present z2 embodiment, there are three stop pins. The top ends of 13 the stop pins 80 are spaced away from the bottom end of i4 the vertical wall 76 of the baffle 74. Because the is chimney assembly 50 is movable vertically due to its ss connection to the housing 12 by means of the flexible i7 membrane 64, the stop pins 80 provide a lower limit to is the movement of the chimney assembly 50. In a present is embodiment, the stop pins 80 are spaced so that when ao the lower edge of the vertical wall 76 of the baffle 74 ai is brought into contact with the stop pins 80, a space 2a 'h' is provided between the diverter 60 and the upper 2s surface 39 of the nozzle assembly 24. In a preferred 24 embodiment, the space 'h' is approximately between 2s 0.025 and 0.045 inches, or more preferably 26 approximately between 0.030 and 0.040 inches, and most 2~ preferably approximately 0.033 inches.
2a In alternative embodiments, movement of the 2s diverter 60 toward the nozzle assembly 24 may be so limited by means other than stop pins. For example, if 31 the housing were formed by an injection molding sa process, steps, shoulders, fins, or other structures, ss may be provided along the walls of the housing in order 34 to limit the downward travel of the chimney and/or ' 35 diverter.
ss Also located in the chamber 14 is a diverting ring ' a~ 82. The diverting ring 82 is located on the inner wall - l0 -W~3 97129799 PCT/CA97/00096 i of the cylindrical portion 18 of the housing 12.
a Specifically, the diverting ring 82 is positioned a adjacent to the baffle 74. The diverting ring 82 is - 4 sized to define a gap 86 around the baffle 74. The s diverting ring 82 serves to impede large droplets of s liquid that might form on the inner wall of the housing . 7 12 and divert large droplets back down into the a reservoir 23 at the bottom of the housing 12. In s addition, the diverting ring 82 serves to provide a Zo relatively tortuous path for the flow of aerosol m particles from the lower portion of the chamber 14 to za the upper portion. This tortuous path also serves to Zs reduce the presence of larger particles and helps to i4 make the particle size distribution more uniform.
is As mentioned above, the bottom of the chamber 14 Zs serves as a reservoir 23 for a liquid to be nebulized.
s~ In a present embodiment, the reservoir has a funnel-ia like shape to direct the liquid to be nebulized in a as downward direction toward the inlet 44. The reservoir ao portion of the chamber 14 is formed of at least two ai portions or stages. In a present embodiment, an upper z2 portion 88 of the reservoir is relatively wide having a za diameter approximately the same as that of the a4 cylindrical portion 18 of the housing 12 (e. g. 2.36 2s in). The upper portion 88 is relatively shallow (e. g.
2s 0.3125-0.25 in). The upper portion 88 of the reservoir 27 tapers in a funnel-like manner toward a lower portion as 90 (or secondary well) of the reservoir. The lower as portion 90 is relatively narrow, but relatively deep so (e. g. 0.25 in). The lower portion 90 of the reservoir si is slightly wider (e. g. 0.625 in) than the outer s2 diameter of the nozzle assembly 24. The opening 44 33 from which the liquid is drawn is located at the bottom s4 of the lower portion 90 of the reservoir. In a present 3s embodiment, the reservoir 23 also includes an 3s intermediate portion 92 located between the upper 37 portion 88 and the lower portion 90. The intermediate WO 97!29799 PCT/CA97/00096 portion 92 of the reservoir 23 has a height and a width a between that of the upper and lower portions.
3 In the embodiment of the nebulizer shown in 4 Figure 1, the relative sizes and dimensions of the s upper, lower and intermediate portions of the reservoir s 23 contribute to the generation of an aerosol wherein 7 the aerosol particle size and output is relatively a unifarm overall. As described more below, the liquid 9 in the reservoir 23 is drawn through the opening 44 and ~o up the liquid passageway 42 in part by the negative si pressure caused by the flow of gas across the liquid is orifice 46. The suction force provided by the gas flow i3 both draws the liquid up out of the reservoir to the i4 top of the nozzle and entrains the liquid with a is certain velocity in the air flow. As the liquid is is nebulized, the surface level of the liquid in the s~ reservoir goes down, thereby directly increasing the ~.a distance that the liquid has to be drawn up out of the is reservoir to the orifice at the top of the nozzle. As 2o the distance of the top of the nozzle over the liquid ai surface increases, more energy is required to draw the 22 liquid up to the liquid orifice at the top of the 23 nozzle assembly 24. Assuming a relatively constant gas a4 pressure, this increasing distance may have the effect zs of decreasing liquid flow through the liquid orifice 2s which in turn may affect the uniformity of the aerosol 27 particle size and rate.
2s The embodiment of the nebulizer in Figure 1 as reduces this possible adverse effect. With the 3o embodiment of Figure 1, a relatively large portion of sz the liquid is stored in the upper portion 88 of the s2 reservoir and a relatively smaller portion of the 33 liquid is stored in the lower portion 90 of the 34 reservoir. Since the large portion 88 of the reservoir as is wide and relatively shallow, the surface level of as the liquid in the reservoir changes relatively slightly s~ as the liquid in this portion of the reservoir is drawn i down. Therefore, there is little change in the energy 2 needed to draw this amount of liquid up from the s reservoir to the liquid orifice 46 as this portion of %~ the l..iquid is depleted. When all the liquid in the s upper portion 88 of the reservoir is nebulized, the s remaining liquid in the lower portion 90 of the ~ reservoir is drawn into the liquid passageway 42 and a the height of the top surface of the liquid falls 9 rapidly. However, since the lower portion 90 of the so reservoir is relatively narrow, it contains only a m small portion of the liquid being nebulized so there is i2 relatively little overall effect on aerosol particle Zs size, and output from this portion of the liquid.
14 Another advantage provided by the funnel shape of ss the reservoir is that the relatively narrow size of the is lower portion 90 of the reservoir has less surface area m thereby directing the liquid toward the opening 44.
is This causes most or all of the liquid to be directed to is opening 44 with little waste.
ao The nebulizer 10 of Figures Z-3 may also include a 21 sensor 89. The sensor 89 may be attached t.o the 2a housing 12 at any suitable location, such as on the 23 cover 21, as shown in Figure 1. The sensor 89 monitors 24 the operating cycles of the nebulizer 10. The sensor 2s 89 may monitor operating cycles by monitoring the 2s movement of the chimney portion 50 relative to the z7 housing body 12. The sensor 89 may utilize any 2e suitable technology, such as electronic, pneumatic, or 2s mechanical. For example, the sensor may be responsive 3o to a change in local capacitance as the chimney moves si closer and further from the top of the housing.
32 Alternatively, the sensor may be responsive to a as embedded magnet, or may measure an optical parameter, ' a4 etc. The sensor 89 monitors the cycles of operation as and provides a count that can be observed by the user 3s or a medical care provider. This enables the user or a~ care provider to estimate how much medication has been z delivered. The sensor 89 includes a display or similar a device for this purpose. In addition, the sensor may s also include appropriate programming to report on the 4 duration, frequency, speed, etc. of nebulizer s operation. These parameters may also be provided to s inform the patient or care provider about the delivery of medication. This embodiment of the nebulizer may .
s also include appropriate programming to limit the s amount of medication or drugs that can be administered.
io For example, if the nebulizer is used to deliver drugs si for pain control, such as morphine, the nebulizer can as be programmed to limit the amount of such drugs that ss can be delivered to the patient.
s4 The embodiment of the nebulizer shown in Figures 15 1-3 is adapted for use by a spontaneously breathing as patient, so the aerosol from the nebulizer is output to i~ a mouthpiece or mask that can be used by the is spontaneously breathing patient. Accordingly, located s9 in an upper portion of the chamber 14 is an adapter 99 Zo having an outlet 98 that connects to a mouthpiece 100.
2i In alternative embodiments, as described further below, a2 the nebulizer may be used with ventilator systems and 23 instead of the mouthpiece 100, the adapter 99 would a4 connect the outlet 98 to the ventilator circuit.
25 To operate the nebulizer 10, a suitable amount of 2s a liquid such as a medicine or water is placed in the a~ reservoir of the chamber 14. The liquid may be placed 2s in the reservoir by first removing the cover 21, as membrane 64, and chimney 50, filling an appropriate so amount of liquid into the reservoir, and replacing the 31 cover 21, membrane 64, and chimney 50 onto the housing 32 12. In a preferred embodiment, the cover, membrane and ss chimney are assembled together and would be removable s~ together as a unit. (Alternatively, the liquid may be 35 placed into the reservoir through the mouthpiece 100, as or further, the nebulizer may be provided pre-filled s7 with the appropriate amount of medicine from the i manufacturer, or in yet another alternative, the 2 nebulizer may be provided with a resealable fill port.) s The source of pressurized gas 27 is connected to the - 4 fitting 28. The source of pressurized gas 27 may be an s external source that provides gas at a rate of 4 to 10 s liters per minute in a range from 35 p.s.i to 50 p.s.i, 7 although other rates and pressures could also be s suitable. Gas is delivered through the passageway 34 s and is expelled from the gas outlet orifice 38 into the ~io chamber Z4. However, at this stage, prior to m inhalation by the patient, the gas travels upward from i2 the gas outlet orifice 38 and nebulization does not z3 occur since the diverter 60 is in the non-nebulizing 14 position. The membrane 64 holds the chimney assembly i5 50, including the diverter 60, away from the nozzle 24.
16 When in the non-nebulizing position, the distance 1~ between the diverter 60 and the top of the nozzle is is approximately 0.15 inches. At this distance, the gap i9 between the diverter 60 and the nozzle 24 is such that 2o the flow of gas does not create sufficient negative zi pressure over the liquid orifice 46 to draw out the z2 liquid.
za To generate an aerosol with the nebulizer, the z4 patient places the mouthpiece 100 to his/her mouth.
25 When the patient inhales, air is withdrawn from the 2s chamber 14 reducing the pressure inside the housing 12.
z~ The lower pressure in the chamber 14 causes the 2s~ membrane 64 to flex drawing the chimney 50 down. The 2s lower position of the chimney 50 is shown in Figure lA.
3o Downward movement of the chimney 50 is limited by the sz stop pins 80. When the stop pins 80 limit the downward s2 movement of the chimney 50, the diverter 60 is spaced a 33 predetermined distance 'h' from the top surface 39 of - s4 the nozzle assembly 24. In a present embodiment, the 35 gap 'h' is approximately 0.033 inches.
- as The pressurized gas, which may be continuously s~ injected into the nebulizer through the fitting 38, is i diverted sideways approximately 90° by the diverter 60.
a Since the gas outlet orifice 38, diverter 60 and nozzle 3 top 39 are generally circular, gas exiting the orifice 4 38 is dispersed evenly in an approximately 360° or s radial pattern. The liquid medicine in the reservoir , 6 is then drawn up the passageway 42 and out of the liquid outlet orifice 46 in part by the negative s pressure caused by the moving gas passing over the 9 liquid outlet orifice. The liquid drawn into the Zo diverted gas stream is aerosolized at least by the time m it reaches the larger volume space of the chamber. In i2 a present embodiment, the liquid medicine drawn out of ~.s the liquid orifice 46 has little or no impaction i4 against the diverter 60. However, in an alternative .i5 embodiment, the liquid drawn into the gas stream may be is directed against the diverter 60.
s~ As the liquid is nebulized it travels into the zs chamber 14 along a path around the lower edge of the 19 baffle 74. As the patient inhales, the nebulized 20 liquid travels upward through the gap 86 between the 21 baffle 74 and the diverting ring 82, and out through a2 the mouthpiece 100 to the patient's respiratory tract.
23 When the patient ceases to inhale, the pressure in a4 the chamber 14 rises. The biasing of the membrane 64 2s is again sufficient to move the chimney 50 upward, 2s increasing the distance between the diverter 60 and the 2~ top surface 39 of the nozzle assembly 24, and causing ae nebulization of the liquid to cease. In alternative as embodiments, a spring, pneumatic valve, or other so biasing device~may be utilized, alone or in combination ss with each other and the membrane, to move the diverter 32 60 into a non-nebulizing position. Thus, the nebulizer ss automatically cycles aerosol generation in time with the breathing cycle of the patient. ' .ss If the patient exhales into the nebulizer, no 36 nebulization occurs since the diverter 60 is in the s~ non-nebulizing position due to the biasing of the 'WO 97J29799 PCT/CA97/OQ096 i membrane 64. Upward travel of the chimney 50 is 2 limited by the cover 21.
a During inhalation, some air flow may be provided through the nebulizer in a path through the chimney 50.
s This air flow into the chamber 14 may be provided from s ambient in a path provided through the ports 72, the _ 7 chimney inlet 56, the chimney passageway 52, and the s chimney outlet 58. This air flow may continue during s both inhalation when the chimney 50 is in the lower Zo position and exhalation when the chimney is in the zi higher position. Alternatively, the air flow through m the chimney 50 may be stopped or reduced during ss inhalation when the chimney 50 is in the lower 14 position. Control of the airflow through the nebulizer ~.s during inhalation or exhalation may be effected by is suitable selections of the dimensions of the chimney i7 inlet 56, the chimney outlet 58, the actuator ports 72, is the diverter ring 82, and other components that affect zs airflow through the chamber, such as any filters.
so In the embodiment described above, the membrane 64 2~. provides an elastic triggering threshold that permits 22 cyclical nebulization to occur that coincides with the 2a breathing of the patient. This threshold is set to 24 fall within normal human breathing parameters so that 2s the diverter moves into and out of proximity with the as nozzle top as a result of the patient's normal a7 breathing. In one embodiment, this level may be as approximately less than or equal to 3.0 cm of water.
2s It can be appreciated that the threshold may be so established at different levels to account for ai different classes of patients. For example, if the sa nebulizer is designed to be used with infants or neo-3s natals, the elastic threshold of the membrane may be 34 lower than the threshold used for adults. Similarly, a 35 different threshold may be used for geriatric patients.
ss The nebulizer may be used also for veterinary s~ applications, such as equine or canine. In veterinary WO 97!29799 PCT/CA97/0009G
z applications, there may be a relatively wide range of 2 thresholds related to the various sizes of animals.
3 Nebulizers having suitably chosen operating thresholds ~4 can be designed for veterinary uses. It is also s recognized that the openings into the chamber, such as s the opening 56, may affect the operating threshold for nebulization. Thus, the operating threshold of the _ s nebulizer may be made readily adjustable by making the actuator 68 adjustable. Alternatively, the operating so threshold may be adjusted by selection of the size of il the openings 56 and 72 into the chamber which would 12 also control air entrainment. This would permit the ss user to adjust the thresholds, if desired. By z4 appropriate adjustment of the operating thresholds, is flow control through the nebulizer can be provided.
is For example, it may be desirable that the patient not i~ inhale or exhale too quickly or too deeply. For is adults, a suitable flow rate may be approximately 30-60 zs liters/minute. The openings into and out of the 2o chamber may be suitably adjusted to provide for these zi rates .
22 The nebulizer may be operated manually instead of 23 relying on the breath-actuated feature. To operate the a4 nebulizer manually, the actuator 70 is pressed down 2s toward the cover 21. As mentioned above, the actuator 2s 70 is connected to the chimney 50. Pressing the a~ actuator 70 brings the diverter 60 down into the 2e nebulizing position close to the nozzle 24. Release of a9 the actuator 70 causes the chimney 50 to rise due to so the biasing of the membrane 64 thereby causing si nebulization to cease.
a2 Referring to Figures 4 and 4A, the indicators 69A
ss and 69B provide a convenient way to confirm the 34 operation of the nebulizer. As mentioned above; when ss the diverter 60 is spaced away from the top of the 3s nozzle 24, no aerosol is being generated. When the 37 diverter 60 is spaced away the actuator 68, the _ 18 _ WO 97/29799 PCTlCA97/OQ096 i actuator 68, which is connected to the diverter 60 a through the chimney 50, is in an upper position and the 3 red indicator 69A on the side of the actuator 68 is 4- visible along the top side 21 of the nebulizer 10, as s shown in Figure 4. When the patient inhales s sufficiently to bring the diverter 60 into a lower 7 position, the red indicator 69A on the side of the s actuator 68 is withdrawn through the opening 56 in the s top side 21 of the nebulizer 10. The red indicator 69A
io is no longer visible, however, the green indicator 69B, zi which is located above the red indicator 69A, remains i2 visible at the top 21 of the nebulizer. Thus, a Za patient or medical attendant can readily determine i4 whether the nebulizer is operating. In embodiments of is the nebulizer for children, the actuator and/or zs indicators can be designed with comic figures.
The breath actuation of the nebulizer is is convenient and efficient. By cycling the nebulization is of the liquid, the nebulizer can be more efficient ao thereby reducing the cost of the therapy.
21 An important advantage follows from the feature of 22 this nebulizer that nebulization can be cycled so as to a3 occur in coordination with a physiological cycle of the a4 patient. Specifically, by nebulizing only during an as inhalation, for example, the dosage of medication as delivered to the patient can be more accurately 2~ delivered and monitored. This enables this embodiment as of the nebulizer to provide for dosimetric medication 29 delivery to an extent that has been otherwise ao unavailable. By limiting the medication delivery to 31 the inhalation cycle of the patient, a dosimetric s2 portion of the medication can be provided.
33 In addition, the nebulizer 10 provides for high a4 output' and uniform nebulization due to the arrangement ss of the gas and liquid orifices 38 and 46 relative to ~ ss the diverter 60. The annular configuration of the a7 liquid orifice 46 relative to the gas orifice provides for aerosol generation in a approximately 360 direction. This enables a relatively high and uniform 3 rate of nebulization. The uniformity it enhanced because the nebulization is formed with little ar no s impaetion of liquid against the diverter.
In alternative embodiments of the nebulizer, the cover 12 may include an air filter that covers the air a inlet 56. The filter would serve to keep contaminants out o:f the chamber and deter the escape of nebulized to liquid. Such a filter may be removable to permit 11 simple, inexpensive replacement.
i2 Ln a still furthez- embodiment, the nebul.izer may is be used in conjunction with an aerosolization spacer, such as an Ae:rochamber~' sold by Trudell Medical is Partnership oL London, Ontario. The Aerochamber spacer is is described .in U.S. Pat. No. 4,470,41:"
In this alternative embodiment, the output of is the nebulizer would be directed into the inlet of the 2o Aerochamber from which the patient inhales the aerosol 2i through an outlet of the Aerochamber.
a2 Another advantage provided by this embodiment of 23 the nebulizer is that less aerosol is likely to escape 24 to the. surrounding environment. This potentially zs benefits attending care providers who would otherwise 2s be exposed to aerosol medication that is released from 2~ nebulizers that generate on a continuous basis.
za In a present embodiment, the membrane 64 is biased 29 to keep the chimney in are upper, non-nebulizing 3o posit~don except during inhalation. Thus, in the 31 periods of tune between inhalations and exhalations, or 32 if the patient pauses and removes the mouthpiece,, 33 nebulizing doE=s not take place. In alternative 34 embodiments, the membrane 64 may bias the chimney 35 downward so that the nebulizer generates an aerosol or 36 nebula except during exh~,l.ation . This alternati~,re may 3~ not be as efficient as t:.he prior alternative, but may Wa 97129799 PCT/CA97/00096 i still provide significant advantages over nebulizers 2 that generate aerosol continuously.
s In further alternative embodiments of the 4 nebulizer, the gas orifice 38, the gas passageway 34, - s or a portion thereof, may have a shape that modifies s the force of the pressurized gas against the diverter ~ 60. For example, the gas orifice 38 may have a conical s shape that facilitates the change of direction of the s gas when it is directed against the diverter, so that io the force of the gas would not move the diverter away 11 during inhalation thereby helping to direct the gas out lz into the chamber. In other embodiments, the conical ~.a geometry may be varied to tailor gas force and flow.
14 As mentioned above, the membrane 62 serves as a is biasing member that moves the diverter. Preferably, is the membrane is constructed of a silicone rubber z~ material. Other materials capable of repetitive ss flexing, compression or expansion in response to the is force of inhaled or exhaled air, such as a spring, or 2o elastic bellows, may also be used. The biasing member 21 is constructed so that it will move the diverter a 22 predetermined distance away from or toward the nozzle 2s during the course of a patient's spontaneous or 24 ventilated breathing.
2s In a present embodiment, the diverter moves up and 2s down in response to the patient's breathing. However, 2~ in alternative embodiments, the nozzle 24 can move 2s instead of the diverter, or alternatively, both the 29 nozzle and the diverter can move. Also, in a present 3o embodiment, the diverter movement is up and down, but si in alternative embodiments, the movement can be side to 32 side, rotating, or pivoting. Alternatively, instead of 3s moving diverter into proximity with a gas outlet, in 34 alternative embodiments, the liquid jet or orifice can ss be moved toward the gas jet or orifice, or is otherwise ss directed toward the gas jet or orifice, or vice versa.
In effect, alternative embodiments contemplate various 1 means of bringing or diverting the gas and liquid 2 streams into proximity in a cyclical basis.
s Tn alternative embodiments of the nebulizer, the 4 liquid orifice may have shapes other than annular. For s example, the liquid orifice may be located adjacent to s the gas orifice. Alternatively, the liquid orifice may be formed of a series of orifices positioned adjacent _ s or annularly around the gas orifice.
s The nebulizer 10 may also be provided with a io plurality of support legs (not shown) that are is connected around the exterior of the housing 12 and 12 provide support therefor.
is In this embodiment, the diverter 50 moves into 24 proximity with the nozzle 24 due to a negative pressure is in the chamber 14. However, the pressure variance may is also be created by a variance in positive pressure, or 1~ a combination of positive and negative pressures.
is II. Second Embodiment is A second embodiment of a nebulizer is shown in 2o Figure 5. According to this embodiment, a nebulizer 2i 110 has a housing 112 that defines a chamber 114. A
2a lower portion of the chamber 114 serves as a reservoir 23 123 for holding a liquid to be nebulized. Located in a 24 lower portion of the housing 112 is a nozzle assembly 25 124. The nozzle assembly 124 may be similar or 26 identical to the nozzle assembly of the first a~ embodiment, described above. Like the first 2a embodiment, a bottom of the nozzle as assembly 124 has a fitting 128 that can be connected to so a supply of pressured gas 127 by means of conventional 31 tubing 129. Located in the nozzle assembly 124 are s2 inner and outer tubular members that define gas and 33 liquid passageways that exit at gas and liquid orifices s4 at the top of the nozzle assembly 124, as in the first ss embodiment. Like the first embodiment, the gas and 3s liquid orifices preferably have a concentric WO 97!29799 PCT/CA97/00096 z arrangement with the liquid orifice having an annular 2 shape encircling the gas outlet orifice. Also, like 3 the first embodiment, in the embodiment of Figure 5 the 4 reservoir 123 includes a relatively wide, but shallow, . s primary or upper portion 188 and a relatively narrow, s but deep, lower or secondary portion 190.
~ Although this embodiment is shown without a bell-s shaped baffle similar to baffle 74 of the first s embodiment, a baffle may be provided in this io embodiment. If a baffle were provided in this ii embodiment, it would have a construction similar to i2 that of the baffle 74 of Figure 1.
I3 In the embodiment of Figure 5, a chimney 150 is i4 located in an upper portion ofthe housing 112. The s5 chimney includes a first internal passageway 152. In is this embodiment, the internal passageway 152 of the z~ chimney assembly 150 serves as an outlet 198 from the is chamber 114. The outlet connects to a mouthpiece 199, ~s or other suitable means of delivering an aerosol to a 2o patient, such as a mask. A diverter 160 is located at ai and connected to a lower end of the chimney 150. The-22 diverter 160 is located a predetermined distance from 2a the top of the nozzle assembly 124. In this 24 embodiment, this distance is approximately 0.033 as inches. Unlike the first embodiment, the chimney as assembly 150 in this embodiment 7.10 is not movable 2~ between upper and lower positions. Instead, the as chimney assembly 150 is fixed in position so that the 29 diverter 160 is maintained a suitable distance from the so top of the nozzle assembly 124 to generate an aerosol.
si In this embodiment, at least one second air sa passageway 153 is provided. The second air passageway 33 153 is located adjacent to the first air passageway 152 a4 in the chimney assembly 150. The second air passageway as 153 communicates with an inlet opening 161 and a 3s suction chamber 163. The suction chamber 163 is located around a lower end of the chimney assembly 150 i and specifically, around the perimeter of the diverter 2 160. An opening 158 communicates between the suction a chamber 163 and the~chamber 114. As pressurized gas and nebulized liquid flow past the perimeter of the s diverter 160, a pressure variance is created that_d.raws s air from ambient through the inlet opening 161 through 7 the second passage way 153 into the suction chamber s 163. In one embodiment, the pressure variance is a s negative pressure, however, the pressure variance may io also be created by a variance in positive pressure, or m a combination of positive and negative pressures. The sa suction provided at the opening 158 serves to enhance z3 generation of the aerosol.
24 A nebulizing enhancement feature provided by the is nebulizer 110 relates to the shape of wall 171 around is the opening 158. As shown in Figures 5 and 6, the i7 shape of the wall 171 includes a first region 173 and a Za second region 175. The first region 173 is separated is from the second region 175 by a step or shoulder 177.
2o The first region 173 and the second region 175 are ai preferably horizontal, flat surfaces and the shoulder 22 177 is preferably a vertical surface. The wall 171 as also includes a third region 179_ The third region 179 24 is located around the second region 175. The third 25 region 179 is a sloped or angled surface that extends as from the second region 175 to a gap 186 formed adjacent z7 to a diverting ring 182.
2s The shapes of the first, second and third regions 2s 173, 175 and 177 affect the air flow in the chamber so from the diverter. The relative sizes and shapes may 31 be varied to enhance particle size generation and as uniformity. An alternative embodiment of the wall 171 as and regions 173, 175, and 177 is shown in Figure 7. Zn 34 the embodiment of the wall 171A shown in Figure '7, the ss relative sizes of the first region 173A, second region 3s 175A, and third region 177A are modified relative to 37 those in the embodiment of Figure 6. These sizes are i varied to affect the size and uniformity of the 2 particle distribution of the nebula or aerosol.
3 Referring again to Figure 5, located in a wall of ~ the chimney 150 is at least one, and preferably a - s plurality of openings 185. Openings 185 communicate s between the chamber 114 and the first air passageway 152 of the chimney assembly 150.
s Referring to Figures 5 and 8, a diverting ring 182 s may be provided in the chamber 114 to reduce the zo presence of large droplets and help make the aerosol ii delivered to the patient more uniform. As mentioned 12 above in connection with the first embodiment, the i3 diverting ring provides this function, in part, by 14 limiting the migration of droplets on the inside wall ss of the nebulizer housing. In addition, by forming a is barrier on the inside wall of the housing, the i7 diverting ring forces the nebulized aerosol to travel is along a relatively non-linear path to move from the i9 lower part to the upper part of the chamber and out the ao mouthpiece.
2i Referring to Figure 5, to operate the nebulizer 22 1.10, a suitable amount of liquid medicine is placed in 23 reservoir of the chamber 114. The outlet 198 is 24 connected to the mouthpiece 199 in a suitable manner.
2s The source of pressurized gas 127 is connected to the as fitting 128. The flow of gas from the top of the a7 nozzle assembly 124 is directed by the diverter 160 2s ~ across the annular liquid orifice surrounding the gas 2s orifice causing the generation of an aerosol from the so liquid in the reservoir. The aerosol is generated in a 3i 360° direction into the chamber 114 around the nozzle 32 124 and diverter 160.
33 An air flow path is established into the chamber - 34 114 from the inlet 161. The gas provided by the source 35 127 also supplements the air supply into the chamber - ass 114. Air flows into the chamber through the second s7 passageway 153 through the suction chamber 163 and WO 97/29799 PCT/CA97/0009~
1 opening 158. Air flow laden with aerosolized liquid 2 from the chamber 114 travels past the gap 186, through the opening 185, into the first air passageway 152, and ~4 out from the outlet opening 198 to the mouthpiece 199 s or face mask. In this embodiment, nebulization may s proceed continuously, or may be cycled by other means, such as cycling of the gas supply.
Alternative embodiments of the diverting ring s arrangement are shown in Figures 9 and 10.. In Figure ~a 9, the diverting ring 182A extends further toward the 12 chimney 150 almost overlapping an edge 183A at the 12 bottom 150A of the chimney 150. This arrangement 13 provides an even more tortuous pathway for the aerosol 14 than the embodiment shown in Figure 8. The embodiment Zs of Figure 8 may provide an even more uniform particle is distribution. In Figure 10, the passageway between the m diverting ring 182B and the bottom 150B of the chimney sa is extended thereby providing a longer pathway of a Zs narrow dimension. The embodiment of Figure 10 may 2o provide an even more uniform particle distribution than 2s the embodiments of Figures 8 or 9.
22 III. Third Embodiment 23 A nebulizer 210 according to another embodiment of 24 the invention is shown in Figures 11-13. The nebulizer zs 210 is similar to the previous embodiments of the 2s nebulizers discussed above. The nebulizer 210 includes 2~ a housing 212 defining a chamber 214. In the 2$ embodiment of Figure 11, the housing 212 is relatively 2s larger than the housings of the previous embodiments.
3o For example, the housing 212 may have a height of sl approximately 11 cm (4.33 in.) and a diameter of 32 approximately 9 cm (3.54 in.). This enables the s3 nebulizer 210 to hold a correspondingly larger volume s4 of liquid and aerosol. A large size nebulizer, such as shown in Figure 11, may be suitable for certain ss veterinary applications such as for horses, cattle, WO 97/29799 PCT/CA9'7/00096 1 dogs, etc. A larger size nebulizer may also be used 2 with humans for uses such as sputum induction.
3 A fitting 238 connects to a pressurized gas supply (not shown) and an outlet 298 provides nebulized s medicine from the chamber 214 to the patient. The s outlet 298 may connect to a mouthpiece, mask, or . 7 ventilator, as appropriate. Like the first described s embodiment, the nebulizer 210 has a movable chimney 9 250. In the chamber 214 of the nebulizer 210, there so are a plurality of nozzle assemblies 224A, 2248, and ii 224C. Each of these nozzle assemblies may be similar ~.2 to the nozzle assembly 24 of the first embodiment.
13 Each of the nozzle assemblies includes a gas supply i4 passageway, such as 234A, and an annular liquid supply is passageway, such as 242A. At the top ends of each of is the nozzles 224A, 2248, and 224C, the gas passageways 17 of each communicate with gas outlet orifices 238A, is 2388, and 238C, respectively and the liquid passageways is of each communicate with liquid outlet orifices 246A, zo 2468, and 246C. The liquid inlets 244 into each of the 2i nozzles assemblies communicate in common with a zz reservoir 223 formed at the bottom of the chamber 214.
2a Located at the bottom of chimney is a diverter 24 260. The diverter 260 may be formed of a single face 2s or surface, or may be formed of multiple faces or zs surfaces that are aligned with the multiple nozzle 27 assemblies 224A-224C, or alternatively, the diverter zs may be formed as a ring. Further, there may be 2s provided multiple diverters. In a preferred 3o embodiment, there is a space or gap 261 formed 3s centrally in the bottom of the diverter 260 to permit s2 aerosol generation in 360° around each of the nozzles.
33 A membrane 264 may be located at the top of the a4 chimney 250 to provide a biasing function as in. the 3s embodiment of Figure 1. Due to the larger size and - 3s weight of the chimney assembly 250 in the embodiment of a7 Figure 11 relative to the embodiment of Figure 1, a WO 97/29799 PCTlCA97/00096 s biasing member 265 such as a spring may be provided in 2 substitution for or in addition to the membrane 264.
s The spring or other biasing member 265 may be connected 4 to the top of the chimney assembly 250.
s The nebulizer 210 is operated in a manner similar s to the nebulizer shown in Figure 1. Like the nebulizer 7 shown in Figure 1, the nebulizer 210 in Figure 11 is s breath- or pressure-actuated. After a suitable liquid s is stored in the housing 212, the generation of a io nebula or aerosol will cycle with the cyclic decrease ii of pressure in the chamber 214. The decrease of Z2 pressure may be caused by inhalation by the patient, or i3 by action of ventilator. As in the first embodiment, i4 nebulization will cease upon exhalation or in the is absence of inhalation.
ss Because the nebulizer 210 has multiple nozzles s~ 224A-C, a large amount of liquid can be nebulized is quickly. Since the single diverter or connected is multiple diverters move in unison toward the multiple 2o nozzles with the patient's inhalation, the cycling of 2z nebulization is coordinated among all the nozzles.
2a As in the previous embodiments, the annular shape as of each of the liquid orifices provides for a high 24 nebulization generation rate. Although the embodiment as of Figures 11-13 shows three nozzles, there can be any 2s number of multiple nozzles, such as two, four, five, z~ etc .
2e Tn an alternative embodiment, the diverter 260 is 2s rotatable relative to the body 252 of the chimney 150.
3o The diverter 260 may include appropriate vanes, ai channels~or a propeller, that captures some of the a2 pressurized gas flow and causes the diverter 260 to ~3s rotate inside the housing 212. Rotation of the 34 diverter 260 may be used to improve mixing of the ' as aerosol inside the chamber.
. ss This embodiment may also include a bell-shaped ' baffle as shown in the first embodiment.

z IV. Fourth Embodiment 2 Figure 14 shows a fourth embodiment of a nebulizer s of the present invention. This embodiment 310 of the -4 nebulizer is adapted for use with a ventilator circuit 301. The ventilator circuit 301 includes an s inspiratory airflow passageway 302 that delivers air ~ from the ventilator to the patient. This embodiment of 8 the nebulizer 310 is located in the inspiratory airflow s passageway 302 connected between a first length of io inspiratory tubing 303 that delivers air from the 2i ventilator circuit 301 and a second length 304 that i2 delivers air to the patient. The second length of Zs inspiratory tubing 304 may connect to the patient by z4 means of a mask, endotracheal tube, etc.
is Like the embodiment of Figure 1, the embodiment of 1s the nebulizer in Figure 14 is pressure- or breath-i~ actuated. Accordingly, the nebulizer 310 produces an za aerosol in a cyclical manner in coordination with the is breathing or ventilation of the patient. The nebulizer 20 310 has a housing 312 defining a chamber 314. A nozzle ai assembly 324 extends up from the bottom of the chamber 2a 314. Pressurized gas is delivered from a gas orifice 2a at the top end of the nozzle assembly 324 and liquid 24 from a reservoir 323 at the bottom of the chamber 314 2s is drawn up to a liquid orifice also located at the top 2s end of the nozzle assembly 324 as in the first .
2~ embodiment. A chimney assembly 350 extends down from a 2s top of the housing 312. The chimney 350 connects to 29 the housing by means of a flexible, resilient membrane 30 364. A diverter 360 is located at the bottom of the ai chimney assembly 350 directly opposite from the gas and a2 liquid orifices at the top of the nozzle assembly 324.
33 An inlet 356 of the chimney 350 connects to the length ~ 34 Of inspiration tubing 303 from the ventilator circuit 35 301. The inlet 356 communicates with an internal 3s passageway 352 of the chimney assembly 350.
Inspiratory gas from the ventilator 301 enters the i nebulizer 310 via the chimney inlet 356, passes through 2 the passageway 352 of the chimney assembly 350, and s passes into the nebulizer chamber 314 through the - -4 openings 385 located in the wall of the chimney 350.
s The inspired gas exits the nebulizer chamber 314 via an s outlet 398. The outlet 398 connects to the second 7 length of inspiratory tubing 304 which in turn connects a to an endotracheal tube, a mask, or other means (not s shown). This embodiment may also include a bell-shaped to baffle as shown in the first embodiment.
11 In the embodiment of Figure 14, the normal z2 operation of the ventilator circuit 301 causes a z3 sufficient change in the pressure in the nebulizer 310 i4 to induce the chimney assembly 350 to move into and out i5 of proximity with the nozzle assembly 324.
is Accordingly, during an inspiration cycle, the chimney z7 assembly 350, including the diverter 360, will be Za brought into proximity with the top of the nozzle i9 assembly 324 causing nebulization of the liquid (as 2o described above in connection with the first ai embodiment). During an expiratory phase of the 22 ventilator 301, the diverter 350 is positioned away a3 from the nozzle assembly 324 thereby causing 24 nebulization to stop. Nebulization cycles 2s automatically in synchronism with the operation of the 2s ventilator. No extra connection is required beyond z~ that necessary to withdraw the aerosol from the chamber as 314 of the nebulizer 310 into the inspiratory tubing of as the ventilator circuit.
3o V. Fifth embodiment.
si Figure 15 shows a fifth embodiment 410 of the 3a nebulizer of the present invention. Like the previous s3 embodiment, the nebulizer 410 in Figure 15 is adapted ' 34 for use in a ventilator circuit and produces an aerosol s5 in a cyclical manner in coordination with operation of ss the ventilator and/or the breathing of the patient.

i A ventilator circuit 401 has an inspiratory 2 passageway 402 that is formed of a first length of s tubing 403 that connects to the ventilator 401 and a ~4 second length of tubing 404 that connects to a mask s 405, or endotracheal tube, and so on, associated with s the patient. The ventilator circuit 401 also includes 7 an exhalation valve pressure line 406. This exhalation s valve pressure line 406 connects to an exhalation valve s 407, associated with an expiratory passageway 408.
io During ventilation of the patient, pressured gas is zi delivered in the exhalation valve pressure line 406 to i2 the exhalation valve 407 to assist in the cycling of .i3 ventilation of the patient.
14 The nebulizer 410 has a housing 412 defining a i5 chamber 414, and includes a nozzle assembly 424, a is flexible, resilient membrane 462, and a diverter 460, i~ arranged generally as in the previously described ~.s embodiment. Instead of a chimney, the nebulizer 410 ss has a post 450 to which the diverter 460 is connected.
2o Unlike a chimney, the post 450 does not include air.
2i openings or an internal air passageway. The diverter 22 460 is connected to a bottom side of the post directly a3 adjacent from the top of the nozzle assembly 424. The 2~ embodiment of Figure 15 also differs from the previous 2s embodiment in the manner that the ventilator circuit as 401 is connected to the nebulizer 410 and the manner 2~ that the ventilator circuit 401 causes the nebulizer as 410 to cycle nebulization. This embodiment may also as include a bell-shaped baffle as shown in the first so embodiment.
si In Figure 15, the nebulizer housing 412 includes s2 an inlet 456 into the chamber 414. The inlet 456 as connects to the first section 403 of inspiratory tubing ' 34 402 from the ventilator circuit 401. The nebulizer 35 housing 412 also includes an outlet 498 from the - ss chamber 414. The outlet 498 connects to the second section 404 of inspiratory tubing that leads to a z conventional device 405, e.g. an endotracheal tube or 2 mask, from which the patient receives the inspiratory a flow from the ventilator 401 including the aerosol from 4 the nebulizer 410.
Located across the membrane 462 from the .
s nebulization chamber 414 is a passageway 483. The passageway 483 connects to the exhalation valve a pressure line 406 of the ventilator circuit 401 by a suitable means, such as a tee 487. Because the ~.o ventilator 401 cycles air to and from the patient, air m flows in the exhalation valve pressure line 406 in a i2 cyclic manner to operate the exhalation valve 407.
13 This air flow in the exhalation valve pressure line 406 z~ causes a pressure differences with the air in the i5 chamber 414. The membrane 462 is positioned across the is inspiratory flow passageway 402 and the exhalation 17 valve pressure line 406 and therefore senses the is ~ pressure differential across these two passageways. As is in the previous embodiment, the diverter 460 is brought so into proximity with the top of the nozzle assembly 424 ai during the inspiratory phase of the ventilator and a2 brought out of proximity with the top of the nozzle za assembly 424 during the expiratory phase of the a4 ventilator. Accordingly, nebulization occurs during a5 the inspiratory phase and not during the expiratory 2s phase .
2~ VI. Sixth embodiment.
2s Figure is shows a sixth embodiment 510 of the 2s nebulizer of the present invention. This embodiment is 3o similar to the embodiment of the nebulizer 110 in 31 Figure 15. The nebulizer 510 includes a housing 512 32 defining a chamber 514. The chamber 514 has an inlet 33 528 connected to a source of pressurized gas 527 and an s4 outlet 598 connected to a tubing 599, or similar 35 structure, such as a mouthpiece, etc., that leads to ss the patient 596 and from which the patient can inhale WO 97/29799 PCTlCA97/00096 i air and aerosol. Like the embodiment of Figure 5, the 2 nebulizer 510 of Figure 16 may also include an inlet a for air entrainment 562. As in the other embodiment, -4 liquid and gas outlets (not shown) located at the top s of a nozzle 524 directly adjacent a diverter 560 s dispense an aerosol into the chamber 514.
7 The embodiment of the nebulizer 510 includes a a breath-actuation feature that enables the nebulizer to s generate a nebula in cyclic manner in coordination with io a physiological cycle of the patient. In the m embadiment of Figure 15, the breath-actuation feature 1z is external of the nebulizer housing 512. The breath-i3 actuation feature includes a valve 569 or other i4 metering device located in-line with the inlet tubing is 529 that provides the pressurized gas from the source is 527 to the nebulizer inlet 528. A tubing 567 connects 1~ from the outlet tubing 599 to the inlet tubing 529.
~.s The tubing 567 enables the valve 569 to sense the is pressure in the outlet tubing 599. In one embodiment, zo the tubing 567 may be conventional tubing and the valve zi 569 senses the pressure through the tubing 567. The z2 valve 569 is adapted to open and close the delivery of 2s pressurized gas to the nebulizer 510 in coordination z4 with the changes in the pressure in the outlet 599 as z5 sensed via the tubing 567. Specifically, upon 2s inhalation, the pressure in the inlet 599 and the 2~ connecting tubing 567 will be lower, and the valve 569 za will open to allow pressurized gas to be, delivered to 2s the nebulizer 510 thereby causing nebulization to 30 occur. After inhalation, the pressure in the patient 3i outlet 599 and the connecting tubing 567 rises, and the sz valve closes thereby causing nebulization to cease. In 33 this manner, the embodiment of Figure 16 can provide ' 34 similar breath-actuation features as the other ss embodiments discussed above. The tubing 567 and valve 3s 569 may be either re-usable or disposable and may be a~ used with a nebulizer 510 as shown in Figure 16, or may i be used with other types of nebulizers. The tubing 567 a and valve 569 could also be used with vaporizers that 3 are used for providing humidification for ventilated 4 patients. Such vaporizers are used with prefilled bags s of sterilized water, and the tubing 567 and valve_569 s would provide adjustable air entrainment of vapor.' 7 VII. Seventh embodiment.
s Figures 17A and 17B show a seventh embodiment 610 s of the nebulizer of the present invention. This io embodiment is similar to the previous embodiments il wherein a housing 612 defines a chamber 614 for holding i2 and aerosolizing a liquid 625 by means of a pressured is gas supply 627. In this embodiment, a top end of a 14 diverter assembly post 650 is connected to the top side is of the housing so that the bottom surface 660 of the is diverter post 650 is located at a fixed distance, e.g.
17 0.033 inches, from a top 639 of a nozzle assembly 624.
Zs As in the previous embodiments, a gas orifice and a Zs liquid orifice (not shown? are located at the top of ao the nozzle assembly 624. The liquid orifice may be 2i ring-shaped and concentric with the gas orifice, or 22 alternatively, the orifices may be side by side. A
as mouthpiece 700 permits the withdrawal of aerosol and a4 air from the chamber 614. A flexible diaphragm 664 is 2s located in an upper region of the nebulizer chamber 614 as and forms a boundary between the inside of the chamber a~ and the ambient outside. One or more air inlet ports 2s 656 are located on a top side of the housing s12. A
29 filter 639 is located at the top of the diverter post 30 650.
31 A cylindrical shield or collecting surface 633 is sa connected to the flexible diaphragm 664 and extends 33 downward into the chamber 614 over the lower portion of ' 34 the diverter post 650 and the upper portion of the ss nozzle assembly 624. The shield 633 has an inside ' 3s diameter larger than the outside diameters of the WO 9?!29799 PCTlCA97/00096 i diverter post 650 and the nozzle assembly 624 so that 2 it can readily shift relative to these parts. One or 3 more windows 637 are located in the wall of the shield 4 633. The windows 637 are located in the wall of the s cylindrical shield 633 such that when the diaphragm 664 s is in an upper position (as shown in Figure 17B} the . 7 window 637 is not aligned with the gap between nozzle s 624 and the diverter 660. When the shield 633 is in s this upper position, aerosol particles generated by the io flow.of pressured gas across the liquid orifice impact ~.1 upon the inside wall of the cylindrical shield 633 and ~a tend to form into droplets that fall back into the za reservoir. In addition or alternatively, depending on i4 the specific dimensions, the shield 633 may impede the is flow of gas from the pressurized gas orifice across the Zs liquid orifice to the extent that there is insufficient i~ vacuum to draw the liquid out of the liquid orifice.
se In any event, the production of aerosol particles into is the chamber 6z4 is reduced. However, when air is ao withdrawn from the chamber 614, such as when a patient ai inhales through the mouthpiece 700, a decrease in 2s pressure inside the chamber 614 causes the diaphragm 23 664 to flex downward (as shown in Figure 17A). This 24 causes the cylindrical shield 633 to shift into a lower 2s position. When the shield 633 is in a lower position, 2s the window 637 is aligned with the gap between the a7 nozzle 624 and the diverter 660 thereby permitting as aerosol generated from the liquid orifice to escape as into the chamber 614 from which it can be inhaled by 3o the patient.
ai The above embodiments of the nebulizer have been 32 described for use in medical or therapeutic ' 33 applications. It is noted that the principles of the 34 invention disclosed herein may have applicability to - 3s other usages, such as industrial, manufacturing, or ss automotive (e. g. carburetors).

i It is intended that the foregoing detailed 2 description be regarded as illustrative rather than _ _ a limiting, and that it be understood that the following 4 claims, including all equivalents, are intended to s define the scope of this invention.

Claims (10)

WE CLAIM:

1. A nebulizer comprising:

a housing having a chamber for holding an aerosol;

an air outlet communicating with said chamber for permitting said aerosol. to be withdrawn from said chamber;

a liquid outlet located in said chamber;

a pressurized gas outlet located in said chamber adjacent to said liquid outlet;

a diverter located in said chamber and relative to said pressurized gas outlet and said liquid outlet so as to divert pressurized gas from said gas outlet across said liquid outlet to produce said aerosol in cycles in coordination with a patient' s breathing; and a biasing member connected to said diverter wherein said biasing member comprises a flexible membrane.

2. The nebulizer of Claim 1 wherein said diverter discontinues nebulization during patient exhalation.

3. The nebulizer of Claim 1 wherein said nebulizer comprises multiple liquid outlets 7 located in said chamber.

4. The nebulizer of Claim 1 further comprising:

an air inlet communicating with ambient air connected to said air outlet located in said chamber.

5. The nebulizer of Claim 1 comprising a suction chamber communicating with said chamber.

6. The nebulizer of Claim 1 further comprising: a means for limiting movement of said diverter.

7. The nebulizer of Claim 1 wherein during an inhalation, said gas diverter is moved towards said gas outlet and forms a gap therewith such that said pressurized gas p.s directed in a radial direction away from said gas outlet into said chamber, said pressurized gas drawing liquid from said liquid outlet.

8 . The nebulizer of Claim 1 wherein said diverter is movable into a non-nebulizing position away from said gas outlet.

9. The nebulizer of Claim 1, wherein said liquid outlet has an annular shape surrounding said gas outlet.

10. A nebulizer for nebulizing a medication during a patient's inhalation stage comprising:
a housing having a chamber, an air outlet connected to said chamber, and a liquid reservoir;

a biasing member attached to said housing;
an air passageway connecting said chamber to an air supply, said air passageway having a hollow tube, an ambient air opening, and an internal opening;

a variable height nebulizing gap defined at a first boundary by a movable breath-sensitive gas diverter and defined at a second boundary by a fixed nozzle, said gas diverter movable to a nebulizing position by said patient's inhalation, said gas diverter movable to a non-nebulizing position by said patient's exhalation; and said nozzle positioned inside said housing opposite said~
movable gas diverter, said nozzle having a pressurized gas outlet and a liquid outlet, said liquid outlet connected to said liquid reservoir; and wherein said nebulizer comprises multiple liquid outlets located in said chamber.