U.S. patent number 3,826,255 [Application Number 05/265,390] was granted by the patent office on 1974-07-30 for intermittent positive pressure breathing manifold.
This patent grant is currently assigned to Hudson Oxygen Therapy Sales Company. Invention is credited to Donald F. Diedrich, Harold R. Havstad.
United States Patent |
3,826,255 |
Havstad , et al. |
July 30, 1974 |
INTERMITTENT POSITIVE PRESSURE BREATHING MANIFOLD
Abstract
An improved intermittent positive pressure breathing manifold
device comprises a substantially vertical main tube having open
upper and lower ends, a diaphragm adjacent the upper main tube
opening for intermittent closing thereof and which diaphragm is in
sealing engagement with an upper cap portion located above the main
tube, an exhalation port adjacent the upper main tube end and in
communication with the lower main tube opening, and first and
second gas ports along the main tube between the upper and lower
main tube ends. A preferred embodiment includes an improved
nebulizer incorporating an air nozzle and coaxial aspirator cap
each having concentric orifices substantially aligned with the
central vertical axis of the main manifold tube.
Inventors: |
Havstad; Harold R. (Lakewood,
CA), Diedrich; Donald F. (Temecula, CA) |
Assignee: |
Hudson Oxygen Therapy Sales
Company (Temecula, CA)
|
Family
ID: |
23010246 |
Appl.
No.: |
05/265,390 |
Filed: |
June 22, 1972 |
Current U.S.
Class: |
128/200.18;
239/338; 128/200.21; 261/DIG.65 |
Current CPC
Class: |
A61M
16/16 (20130101); A61M 16/0833 (20140204); A61M
11/06 (20130101); A61M 16/08 (20130101); Y10S
261/65 (20130101) |
Current International
Class: |
A61M
16/16 (20060101); A61M 16/10 (20060101); A61M
11/06 (20060101); A61M 16/08 (20060101); A61m
011/00 () |
Field of
Search: |
;128/194,195,196,185,186,188,145.5,145.6,145.8 ;137/63,102
;239/338 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Cohen; Lee S.
Attorney, Agent or Firm: Seiler; Jerry R.
Claims
I claim:
1. An IPPB manifold device for use with an IPPB respirator of
either of two types, type (i) providing a main stream of gas and
two minor gas streams during patient inspiration and type (ii)
providing a main stream of gas and one minor gas stream during
patient inspiration, the manifold comprising:
a. a hollow main tube being elongated along a vertical axis and
terminating at openings at both the upper and lower tube ends;
b. a nebulizer attached to the lower end of said main tube said
nebulizer comprising an air nozzle provided with gas inlet means
and having an upper orifice and an aspirator cap provided with
liquid inlet means and having an upper orifice said air nozzle and
aspirator cap orifices being coaxially aligned with said main tube
whereby aerosol emanating from said aspirator cap orifice is
directed upwardly toward said lower tube opening and into said main
tube;
c. a diaphragm for alternately closing the upper main tube opening
and in sealing engagement with an upper cap portion having an air
supply conduit means and wherein said cap and diaphragm define a
gas pressure chamber therebetween with which chamber the conduit
means communicates said conduit means comprising first and second
pipes, whereby in use with said type (i) respirator a first gas
supply tube is attached between the first pipe and said respirator
for delivering one of said minor gas streams to said pressure
chamber and said second pipe is stoppered, and a second gas supply
tube is attached between said respirator and said nebulizer for
delivering the other of said minor gas streams thereto, and in use
with said type (ii) respirator a third gas supply tube is attached
between the first one of said pipes and said respirator for
delivering the minor gas stream to said pressure chamber and a
fourth gas supply tube is attached between said second pipe and
said nebulizer for directing a portion of said minor gas stream
from said chamber thereto;
d. a walled housing member for receiving said diaphragm having a
lower end radially extending from and secured to said main tube
adjacent the upper tube end and having and upper rim to which said
upper cap is secured;
e. an exhalation port adjacent said upper main tube end and
extending through said walled housing member; and
f. a tubular gas inlet port and a tubular gas outlet port
oppositely disposed along said main tube and extending normal to
the vertical axis thereof between said upper and lower main tube
ends wherein a gas supply hose is attached between said respirator
and said gas inlet port for delivering said main stream of gas to
said device and from said gas outlet port to a patient, whereby
said main gas stream flowing from said gas inlet port to said
outlet port passes across said main tube where it is combined with
said aerosol.
2. The device of claim 1 wherein said diaphragm includes a flange
therearound which flange is sealingly engaged between said upper
cap and the upper rim of said walled housing member.
3. The device of claim 1 wherein said nebulizer further comprises a
jar portion having sides, bottom and top defining a nebulizing
chamber, said aspirator cap being coaxially mounted on said air
nozzle, said air and aspirator cap orifices being spaced apart to
define an aspirating chamber therebetween and wherein the distance
between said aspirator cap orifice and said air nozzle orifice is
greater than the diameter of either of said orifices.
4. The device of claim 3 wherein the diameter of said air nozzle
orifice is smaller than the diameter of said aspirator cap
orifice.
5. The nebulizer of claim 4 including a baffle axially disposed
adjacent said aspirator cap orifice.
6. An IPPB manifold device for use with an IPPB respirator of
either of two types, type (i) providing a main stream of gas and
two minor gas streams during patient inspiration and type (ii)
providing a main stream of gas and one minor gas stream during
patient inspiration, the manifold comprising:
a. a hollow main tube being elongated along a vertical axis and
terminating at openings at both the upper and lower tube ends;
b. a nebulizer attached to the lower end of said main tube said
nebulizer comprising an air nozzle provided with gas inlet means
and having an upper orifice and an aspirator cap provided with
liquid inlet means and having an upper orifice said air nozzle and
aspirator cap orifices being coaxially aligned with said main tube
whereby aerosol emanating from said aspirator cap orifice is
directed upwardly toward said lower tube opening and into said main
tube;
c. a diaphragm for alternately closing the upper main tube opening
and in sealing engagement with an upper cap portion having a single
air supply pipe and wherein said cap and diaphragm define a gas
pressure chamber therebetween said pipe communiating therewith
whereby in use with said type (i) respirator a first gas supply
tube is attached between said pipe and said respirator for delivery
of one of said minor gas streams to said pressure chamber and a
second gas supply tube is attached between said respirator and said
nebulizer for delivering the other of said minor gas streams
thereto, and in use with said type (ii) respirator said device
includes a gas flow restricting and splitting member having an air
inlet for receiving said minor gas stream from said respirator, and
first and second gas outlets, the first outlet being attached to
said pipe for supplying a portion of said minor gas stream to said
pressure chamber and the second outlet for supplying a portion of
said minor gas stream to said nebulizer;
d. a walled housing member for receiving said diaphragm having a
lower end radially extending from and secured to said main tube
adjacent the upper tube end and having an upper rim to which said
upper cap is secured;
e. an exhalation port adjacent said upper main tube end and
extending through said walled housing member; and
f. a tubular gas inlet port and a tubular gas outlet port
oppositely disposed along said main tube and extending normal to
the vertical axis thereof between said upper and lower main tube
ends wherein a gas supply hose is attached between said respirator
and said gas inlet port for delivering said main stream of gas to
said device and from said gas outlet port to a patient, whereby
said main gas stream flowing from said gas inlet port to said
outlet port passes across said main tube where it is combined with
said aerosol.
7. The device of claim 6 wherein said diaphragm includes a flange
therearound which flange is sealingly engaged between said upper
cap and the upper rim of said walled housing member.
8. The device of claim 6 wherein said nebulizer further comprises a
jar portion having sides, bottom and top defining a nebulizing
chamber, said aspirator cap being coaxially mounted on said air
nozzle, said air and aspirator cap orifices being spaced apart to
define an aspirating chamber therebetween and wherein the distance
between said aspirator cap orifice and said air nozzle orifice is
greater than the diameter of either of said orifices.
9. The device of claim 8 wherein the diameter of said air nozzle
orifice is smaller than the diameter of said aspirator cap
orifice.
10. The nebulizer of claim 9 including a baffle axially disposed
adjacent said aspirator cap orifice.
Description
BACKGROUND OF THE INVENTION
Intermittent positive pressure breathing devices, commonly referred
to as IPPB devices have been utilized for some time. The most
commonly known devices are the Bird and Bennett IPPB units and
incorporate various valves and pressure regulating means as
generally described, for example, in U.S. Pat. Nos. 3,234,932 and
3,265,061, respectively. These units deliver oxygen or oxygen
enriched gas mixture to a patient under pressure upon inspiration.
As the patient's lungs become filled, the gas flow is automatically
terminated by flow sensing means and the patient may exhale
normally during the breathing cycle. The devices are also sometimes
referred to as respirators, ventilators or respiration control
units. Again, these and similar devices supply the air or oxygen
enriched gases to a patient under pressure during the inhalation
breathing phase and, through the various valves and flow sensing
means terminate the oxygen or air flow once the lungs have been
filled to the desired capacity.
The above-described devices, hereinafter referred to as control
units, are used in combination with a gas delivery assembly of the
type described in U.S. Pat. No. 3,265,061 or breather head assembly
disclosed in U.S. Pat. No. 3,234,932 or control and exhaust valve
assembly such as disclosed in U.S. Pat. No. 3,584,621. Such
assemblies are often referred to as IPPB manifold assembly devices
and accordingly, the term "manifold" will be used to so designate
hereinafter. The manifold is attached to the gas supply tube or
tubes which deliver pressurized oxygen or oxygen containing gas
from the control unit. The manifold works in cooperation with the
control unit to provide for intermittent gas delivery to the
patient and to allow for unobstructed expiration of the gas.
As evidenced by the devices disclosed in the aforesaid patents,
prior art manifolds incorporate a number of individual parts and
are thus rather complex in construction as well as having other
disadvantages. Disadvantages in producing the device having a
number of individual parts or components which must be fitted and
interlocked together during manufacture and assembly are self
evident. Especially, from a manufacturing standpoint, the various
parts must be indivdually molded or stamped requiring a variety of
dies. These individual parts then must be hand or machine assembled
thereby further increasing their costs.
Not only are such manifolds undesirable from a manufacturing or
production standpoint but because of the rather complex
construction including plurality of fitting parts gas leakage may
occur with concomitant reduction in efficiency unless the fittings
are made correctly and the components properly secured. Such a
plurality of component parts also lends to instances of improper
assembly which, of course, requires time consuming inspection and
quality control thereby increasing product costs. Moreover, because
of the design of interior passageways of most prior art manifolds,
pockets or crevices are present in which foreign material or
bacteria may lodge. Even though the devices are made of plastic and
are intended for single patient use and thereafter disposed,
certain bacteria or virus may grow rapidly in a relatively short
period of time. The elimination of such disadvantages is especially
important when the manifolds are used to treat patients having lung
or respiratory ailments. Moreover, where gases are required to flow
through or between offset or angled passageways, air flow may be
somewhat impeded and undesirable turbulence created.
Manifolds are often used in combination with a neubulizer when it
is desirable to humidify the oxygen or oxygen containing gases
administered to the patient or to create a mist or vapor of fine
particles of water or medicament in the treatment of certain
respiratory disorders. Certain prior art manifolds require the
neubulizer to be offset from the normal gas flow. Such devices also
usually create a slip-stream or internally baffled main stream gas
flow in order to induce pick-up of the mist generated by the
neubulizer. Such techniques do not utilize maximum nebulizer
advantages and create inefficiencies because of the manner in which
the nebulized particles must travel within the device prior to
reaching the main oxygen flow to the patient.
Finally, there is a need for a simply designed and uniformly
constructed manifold which can be easily adapted to use for either
Bird or Bennett respiration control units. It is to the elimination
of the above-noted disadvantages and for the production of a
manifold and nebulizer assembly which can be inexpensively produced
and yet be adaptable to either of the types of respiratory control
devices as noted that the present invention is directed.
SUMMARY OF THE INVENTION
The manifold device of the present invention is intended to obviate
the disadvantages noted hereinabove. The device, excluding the
nebulizer portion incorporates a minimum number of components
whereby the necessity of fitting or snapping together a number of
individually molded parts is not required. Thus, the cost of
manufacture, assembly and inspection is significantly reduced as
well as substantially eliminating possible dangers of improper
assembly, leakage around fitted parts, joints and the like.
The device comprises an elongated substantially vertical main tube
portion having a pair of oppositely disposed tubular ports
extending substantially normal to the main tube axis. The first of
said ports is for attaching a gas supply conduit from an IPPB
control unit and thus receives air or oxygen enriched air from the
control unit during patient inspiration. The second, and oppositely
disposed port is for attaching a mouthpiece or conduit directed to
a mouthpiece, mask or similar device by which a patient may receive
air or oxygen enriched air during inspiration. This second port
also receives expired gases from the patient which are then
directed into the manifold and expelled as will be explained
further hereinafter.
Disposed adjacent the upper end of the main tube is an exhalation
valve assembly including an exhalation port through which expired
gases are directed, and a diaphragm disposed across the upper main
tube opening for intermittently opening and closing the opening in
response to pressure in a diaphragm chamber. The diaphragm is in
sealed engagement with an exhalation valve cap and therebetween is
defined the diaphragm chamber. Extending from the exhalation valve
cap are a pair of hollow pipes which communicate with the diaphragm
chamber through orifices in the valve cap. Alternatively one pipe
may be used in combination with a gas flow restricting member as
will be more fully explained hereinafter.
A further embodiment includes an improved nebulizer secured to the
lower end of the main manifold tube. The manifold device, in
addition to having relatively few parts including the neubulizer
portion extends generally along the vertical axis of the main
manifold tube. Thus, the exhalation valve assembly is located
directly above and substantially coaxial to the main manifold tube
while the nebulizer portion, also coaxial with the main tube is
located at the lower tube end. Accordingly, the device, having only
tubes and ports extending therefrom is balanced, with the center of
the balance or gravity extending substantially along the main
manifold tube vertical axis. This feature is important in utilizing
the nebulizer whereby the medicament or water level therein will be
substantially normal to the main tube vertical axis. Other
advantages as well as the operational features of the device will
be more fully explained hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the manifold device of the
invention partially in section to expose the interior thereof;
FIG. 2 is a bottom plan view of the exhalation valve cap;
FIG. 3 is a perspective view of the device showing tube
attachements used with a Bennett IPPB unit;
FIG. 4 is a perspective view of the device showing tube
attachements for use with a Bird IPPB unit;
FIG. 5 is a perspective view of an alternative exhalation valve cap
and gas flow restrictor as used for a Bird IPPB unit;
FIG. 6 is a top plan view of the manifold device with the
exhalation valve cap removed;
FIG. 7 is a bottom plan view of the manifold device with the
nebulizer assembly removed;
FIG. 8 is a perspective view of the diaphragm;
FIG. 9 is a side sectional elevation of a gas flow restrictor;
FIG. 10 illustrates the lower portion of the manifold device
including a side sectional elevation of the nebulizer assembly;
FIG. 11 is an enlarged sectional elevational view of the air nozzle
and aspirator cap portion of the nebulizer assembly; and
FIG. 12 is a sectional view taken along line B--B of FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, the manifold device 10 comprises an
elongated vertical main tube 12 which terminates at an upper end 22
and lower end 18. The tube is substantially hollow along its entire
length with openings at the respective upper and lower ends 22 and
18. The main tube interior is preferably of a substantial uniform
diameter between the ends. Adjacent the lower main tube end is a
nebulizer cap 14 which cap is secured to the main tube and
preferably integral therewith. The lower portion of main tube 12
extends through nebulizer cap 14 and into the cavity of nebulizer
jar 16 when the latter is attached to the cap. The cap is also
preferably provided with threads for threadedly engaging the
nebulizer jar.
At the upper end of main tube 12 is an exhalation valve assembly 24
which includes annular exhalation valve housing 25 (note FIG. 6),
diaphragm 36, exhalation valve cap 28, exhalation port 38 and pipes
30 and 32 (note FIG. 2). Referring also to FIG. 6, valve housing 25
includes annular sidewall 72 extending upwardly from valve housing
base 74. A normally extending flange 76 is preferably formed around
at the upper end of sidewall 72, the upper surface of which flange
provides a seat for seating engagement with a diaphragm as will be
pointed out hereinafter. It will be noted that an upper portion of
the manifold main tube extends into a valve housing cavity defined
within the valve housing which cavity has a greater diameter than
the main tube. However, the shape and size of the exhalation valve
housing is not critical so long as it accomodates the upper portion
of the main manifold tube, the diaphragm and valve cap. A tubular
exhalation port 38 is also secured to and extends from valve
housing 25 so that the exhalation port communicates with the valve
housing cavity through wall 72. Valve housing 25 including sidewall
72, base 74 and exhalation port 38 are also preferably integrally
molded with the main tube.
Referring also to FIG. 2, exhalation valve cap 28, provides a
closure for the exhalation valve assembly. The valve cap includes a
pair of hollow pipes 30 and 32 which communicate with channel or
groove 31 formed in the cap which in turn is exposed to a diaphragm
chamber. The valve cap also includes an annular skirt 34 which is
designed to fit over and engage flange 76 at the upper
circumferential end of valve housing sidewall 72. At the top of
valve cap 28 is a ball member 40 used to suspend the manifold
device from a socket or clamp of supporting apparatus.
Referring also to FIG. 8, diaphragm 36 comprises a cup-shpaed
flexible gas impermeable membrane having a substantially flat base
surface 21, sidewall 33 and an upper annular flange 15 which rests
on annular flange 76 of the exhalation valve housing. Thus, when
cap 28 is secured to flange 76 it forces diaphragm flange 15 into
sealed engagement therebetween. Diaphragm chamber 26 is defined
within the diaphragm cup and exhalation valve cap and communicates
with pipes 30 and 32. The diaphragm chamber is alternately
pressurized by introducing gas via the pipes whereby the diaphragm
expands and because of its close proximity to upper main tube end
22, flat base 21 is forced downwardly sealing off the upper main
tube opening. When the diaphragm is not in an expanded state its
base may rest lightly on the upper main tube end or be only
slightly separated therefrom so that expired gases may pass
therebetween.
Extending from exhalation valve assembly 25 is exhalation port 38.
The exhalation port is in communication with the interior cavity
defined by valve housing 25 so that when diaphragm 36 is not
expanded, expired gas from a patient passing into the main tube may
pass through upper main tube opening and exit through exhalation
port 38.
Downwardly from the exhalation valve assembly along main tube 12
and extending therefrom are a pair of tubular ports 35 and 37.
These ports may be conveniently located approximately midway
between the upper and lower main tube ends. First port 35 directs
air or oxygen enriched air into main tube 12 and second port 37
directs the gas to a patient from main tube 12 and receives expired
patient gases. Because of these functions, ports 35 and 37 are
preferably oppositely disposed on the main tube and extend normal
to vertical main tube axis as shown.
Attached to the lower portion of main tube 12 is a nebulizer
assembly including a nebulizer cap 14 and jar 16. The nebulizer
assembly, which will be described in more detail hereinafter is for
the purpose of creating and directing a mist or aerosol of finely
nebulized water or medicament particles into main tube 12 through
lower tube end 18 during patient inspiration. The aerosol is forced
upwardly along the lower portion of the main tube where it mixes
with air or oxygen enriched air flowing across the main tube
interior from port 35 to port 37 and to the patient.
Noting FIGS. 1 and 10, nebulizer cap 14 includes a flat top portion
17 extending radially from a lower portion of main manifold tube 12
whereby the latter projects downwardly for a distance past the
plane of intersection and into the nebulizer jar cavity. An annular
skirt 39 extends circumferentially from flat top portion 17 and the
inner skirt surface is preferably provided with threads for
theadedly engaging nebulizer jar 16. The nebulizer cap is
preferably integrally molded to main tube 12.
Basically, and referring especially to FIG. 1, the principal of
operation of the manifold device of the invention is as
follows;
On patient inspiration, air or oxygen enriched air is passed from a
respirator or IPPB control unit into first port 35, across the
central interior of main tube 12 and through second port 37 which
is connected by a suitable gas directing conduit such as a flexible
hose and mask or mouthpiece to a patient. At the same time, gas is
forced into the nebulizer through a separate conduit creating an
aerosol which is directed upwardly through lower main tube opening
18 and main tube 12 where it combines with the flow of gas passing
across the main tube from port 35 to port 37. Concurrently,
diaphragm chamber 26 is pressurized by gas supplied through
exhalation valve cap pipe 30 expanding diaphragm 36 and sealing the
upper end 22 of main tube 12. Thus, the diaphragm seal at the upper
main tube end prevents air or oxygen within main tube 12 from
leaking during patient inspiration.
As the patient's lungs become filled with the gas and inspiration
is terminated, a flow sensing means in an IPPB control unit shuts
off the air flow to port 35, diaphragm chamber 26 and to the
nebulizer. The pressure in the diaphragm chamber is then dumped
whereby diaphragm 36 returns to an unexpanded position. As this
occurs, the seal at upper main tube opening 22 is relieved and the
patient exhales, expired gases are directed through port 37,
upwardly through the upper portion of the main tube 12, out through
upper main upper tube opening 22 and exhalation port 38. Expired
air is normally not allowed to pass into the nebulizer jar either
when the nebulizer is connected for nebulization or when it is
sealed off. However, expired patient gases normally may not pass
back through port 35 or into the nebulizer through the main tube
becuase of static pressures.
Referring now to FIGS. 3 and 4, there are shown two different means
for connecting the manifold device of the invention, FIG. 3
illustrating the manner for connecting the unit to a Bennett IPPB
control unit, and FIG. 4 for connection to a Bird unit. Referring
first to FIGS. 1 and 3, line 50 is connected between a Bennett IPPB
unit (not shown) and exhalation valve pipe 30. It will be noted
that second pipe 32 is sealed off by cap 48 so that only one of the
pipes is utilized in the Bennett mode. Nebulizer supply line 56 is
attached via hose connector 61 between nebulizer 16 and to a
nebulizer gas pressure outlet on the Bennett unit. A larger
flexible supply conduit 20 is attached between the Bennett device
and main oxygen inlet port 35. The second port 37 is attached to
mouthpiece 23 for delivery of the oxygen enriched gas to a
patient.
In operation, during patient inspiration the Bennett unit will
supply air or oxygen enriched air to the nebulizer through supply
line 56, at a constant pressure, usually between about 40 psi and
about 60 psi during inspiration. At the same time, the Bennett unit
supplies gas under pressure via control line 50 to pipe 30 and into
diaphragm chamber 26 thereby expanding diaphragm 36 to seal off
upper main tube end 22 of the manifold. Oxygen or oxygen enriched
gas to be inhaled by the patient is supplied by conduit 20 via
ports 35 and 37. Again, it will be appreciated that during patient
inspiration as the pressure is continuously being supplied to the
nebulizer via line 56, fine medicament or water particles in the
form of an aerosol are combined and mixed with gas in main tube 12
and directed to the patient.
As the patient's lungs become filled and he begins to exhale the
pressure change will be sensed by the Bennett unit and gas flow is
terminated. Gas pressure in the diaphragm chamber is "dumped" by
the control unit via pipe 30 and control line 50 and oxygen
supplied to the nebulizer and port 35 ceases. As pressure within
the diaphragm chamber is relieved the diaphragm no longer seals the
opening at upper end 22 of main tube 12. Accordingly, expired gases
will pass through tube 21, port 37, into main tube 12, upwardly
through main tube 12 and out through end 22 and exhalation port
38.
FIG. 4 illustrates the manifold device as it is used with a Bird
IPPB unit. It will be noted that pipe 32 is not capped but instead
communicates with nebulizer 16 via supply line 58. Because a Bird
respirator is a single line-type, it does not have a separate
nebulizer gas pressure supply line. Thus, when using a Bird unit
gas to the nebulizer is supplied through the diaphragm chamber.
Referring also to FIG. 1, gas from the unit (not shown) is directed
via supply line 50 and pipe 30 into diaphragm chamber 26. Again,
this causes the diaphragm to expand and seal off upper end 22 of
main manifold tube 12. Gas supplied by the Bird unit to the
diaphragm chamber via supply line 50, during patient inspiration,
will normally be constant, for example, about 50 psi. Since that
amount of pressure is in excess of that required to maintain the
diaphragm seal, the excess gas is directed to the nebulizer via
pipe 32 and conduit 58. Moreover, the diameter of pipe 32 is
preferably larger than pipe 30 so as to ensure sufficient venting
of gas from the diaphragm chamber to the nebulizer and preventing
undue diaphragm chamber pressure which could rupture the
diaphragm.
Upon termination of patient inspiration and during expiration, the
flow of gas into the diaphragm chamber via line 50 is terminated
thereby allowing pressure in the chamber to be dumped. For this
purpose, an orifice 29 of suitable diameter is present in conduit
58 through which diaphragm chamber pressure will be dumped once the
gas flow in supply line 50 is terminated. The size or diameter of
orifice 29 will be large enough to permit rapid pressure dumping
and yet small enough to allow sufficient gas to be directed to the
nebulizer through the supply line during patient inspiration. It
will also be understood that once the diaphragm pressure is dumped
through the orifice, gas flow to the neubulizer is then also
terminated. Otherwise, the manifold assembly as shown in FIG. 4
operates similar to that as shown in FIG. 3.
Observing again FIG. 3, in the Bennett mode of operation, cap 48 is
provided to seal pipe 32 which is not used. Where the pipes are of
different sizes, both internally and externally, cap 48 will fit
only pipe 32 which reduces the chances of an operator inadvertently
sealing off pipe 30. Such a feature is thus convenient and will
reduce the possibility of an inexperienced operator incorrectly
making the attachments when used in the Bennett mode.
An alternative embodiment of the exhalation valve cap described
hereinabove is shown in FIG. 5 utilizing valve cap 75 having a
single pipe 78 corresponding to pipe 30 previously described and
which pipe communicates with the diaphragm chamber. Thus, in the
Bennett mode in which only one pipe is utilized, this embodiment
will be used and functions substantially as described according to
FIG. 3 but eliminating the requirement of capping a second
pipe.
Where the single pipe embodiment is to be used with a Bird unit it
will be necessary to attach a gas flow restricting and splitting
member 70 which will be referred to as a "T"-adapter hereinafter.
Referring also to FIG. 9, the T-adapter provides a triple function
required for adapting the unit for Bird mode operation. The T
adapter includes three gas directing ports. Port 71 is attached to
control line 50 which directs gas flow from the Bird unit. Port 75
is secured directly to pipe 30 for directing the flow of gas into
the diaphragm chamber while port 72 is secured to nebulizer supply
line 58 which does not have an orifice as does supply line 58.
T-adapter 70 also incorporates restrictor wall 77 having an orifice
73 therein for reducing the gas pressure supplied into the manifold
diaphragm chamber. Thus, orifice 73 will allow a majority of gas
supplied to flow through port 72 to operate the nebulizer and yet
sufficient gas to enter the diaphragm chamber and expand the
diaphragm for sealing the upper end of the main manifold tube
during patient inspiration. A dump vent 74 is located on the low
pressure side of restrictor wall 77 for venting or relieving gas
pressure in the diaphragm chamber when the gas flow from the Bird
unit is terminated during patient expiration and for controlled
leakage preventing unduly high diaphragm pressure buildup during
patient inspiration. Thus, dump vent 74 functionally corresponds to
orifice 29 in nebulizer supply line 58 in the embodiment shown in
FIG. 4.
For normal Bird unit operation where pressure supplied through
control line 50 is about 50 psi, suitable diameters of orifice 73
are between about 0.015 and about 0.025 inch and vent 74 between
about 0.030 and about 0.035 inch and more preferably about 0.019
and about 0.031, respectively.
Alternatively, the T-adapter may be used with the two pipe
embodiment shown in FIG. 4 for the Bird mode. However, only one
pipe will be used with the other pipe closed off or capped and
eliminating the need for supply line 58 having orifice 29. Thus,
the attachments used will corrresppnd to those shown in FIG. 5 with
T-adapter 70 attached to pipe 30 while pipe 32 will be capped (see
FIG. 3).
In still a further embodiment to be used with the Bird unit and
referring to FIG. 4, orifice 29 in supply line 58 may be eliminated
and instead a dump port may be provided on the exhalation valve
cap. However, in order to further restrict unduly great pressure in
the diaphragm chamber a separator disc may be placed between the
valve cap and diaphragm which disc is provided with a restricting
orifice. Thus, the combined orifices and separator disc will
achieve the same function of the T-adapter previously described it
being understood that such functions are required for use in the
Bird mode.
Referring again to FIG. 1, it will be noted that the manifold of
the invention is quite symmetrical since all of the ports as well
as the exhalation valve assembly and nebulizer components are not
substantially displaced or offset from the longituidinal axis of
main tube 12. This construction offers advantages over previous
manifold devices. For example, because of the symmetry of the
manifold and its components, when the device is attached to a
holding arm which fits around ball member 40, because of its center
of gravity along the vertical axis the manifold will remain
substantially upright rather than at an angle relative to vertical.
Such a feature will insure that the water or medicament level
within the nebulizer will be at least nearly normal to the vertical
manifold axis since the nebulizer jar will not be tipped which, if
the water or medicament level was low, could cause nebulizer
inefficiency or malfunction. In addition, as a mist is generated by
the nebulizer it will be forced upwardly directly into the main
manifold tube 12 without passing through any offset chambers or
angled ports prior to being mixed with oxygen which passes across
the flow of mist and is directly mixed with the aerosol. That
feature is also designed to optimize the functions of the device
thereby achieving maximum efficiency. Such features, combined with
the relative simplicity of construction of the device including
minimum number of parts provides not only reduced construction and
assembly costs but the other advantages as noted hereinabove over
prior art devices as will be appreciated by those skilled in the
art.
Expired gases passing from exhalation port 38 may be directed to a
gas analyzer or similar device for measuring the amount or
composition of the expired gas as desired. Thus, if carbon dioxide
concentration, vital capacity or other tests are desired, a
suitable conduit may be attached to exhalation port 38 for
directing the gases to the analyzing equipment. Otherwise, the
expired gas will simply be directed to the room atmosphere. Further
an exhalation retard cap for adjusting exhalation rates may be
attached to the exhalation port.
Referring now to FIGS. 10-12, the improved nebulizer of the
invention is situated directly below the main tube 12 along its
vertical axis. Nebulizer jar 16 is attached to cap 14 which is
affixed to the lower end of main tube 12 as shown. The method of
attachment of the jar to the cap is not critical and it may be
snapped into place or the interior of skirt 39 and the top exterior
side of the jar may be provided threads for threadedly engaging the
two parts as shown in FIG. 1. The shape of the jar is not
particularly critical but it is preferred that it has a bowl-shaped
bottom 62 for improved efficiency as will be explained
hereinafter.
Extending upwardly from bottom 62 and integral therewith is an air
nozzle 44. Preferably, the air nozzle and bowl-shaped bottom are
molded as a portion of the nebulizer jar. It will be noted that
nozzle 44 is elongated and has an interior nozzle cavity 43 through
which gas is upwardly directed. The nozzle terminates at its apex
in a nozzle orifice 49 located along the central vertical axis of
the nozzle. The sides of nozzle 44 are also preferably inclined or
slanted inwardly from the bottom to top so that the diameter of
both the interior and exterior nozzle surface decreases from bottom
to top. A hose connector 61 integral with air nozzle 44 extends
below bottom 62 for attaching a supply line 52. However, the design
of the exterior bottom portion of the nebulizer jar is not critical
and may be as shown or otherwise modified, so long as means for
providing air to the air nozzle is present to achieve the desired
purpose.
An aspirator cap 42 is disposed coaxially on the air nozzle as
shown and substantially covers the air nozzle. Bottom edge 55 of
aspirator 42 does not rest on the bottom surface 62 of jar 16 but
instead is elevated therefrom somewhat to provide a passageway for
water or medicament within the nebulizer chamber defined within the
nebulizer jar. Alternatively, the aspirator cap end may rest on or
be secured to the bowl surface with passageways formed through and
along its lower end. At the upper end of of aspirator cap 42 is an
orifice 47 which is disposed directly in line above orifice 49 of
air nozzle 44. The top surface of both the air nozzle and aspirator
cap may be flattened in the form of a flange having the respective
orifices therein as shown for the air nozzle or one or both may be
formed like that of the aspirator cap (see FIG. 11).
Observing particularly FIG. 12, there is illustrated the
relationship of aspirator cap 42 and air nozzle 44 whereby the
interior sides of the aspirator cap are cut so that a portion of
the interior sides rest against the exterior side surface of the
air nozzle. It will be noted that the interior sides of aspirator
cap 42 are beveled to provide a plurality of channels 53 between
the exterior air nozzle surface and interior aspirator cap surface.
Alternatively the interior aspirator cap surface may be
circumferential and the exterior air nozzle surface beveled to
provide the channels. The channels are in communication with the
space between bottom edge 55 of aspirator cap 42 and bottom 62 of
the nebulizer jar, so that water or medicament can flow into the
aforesaid space and is drawn up through the channels to mixing
chamber 51 (see FIG. 11). Mixing chamber 51 is defined as the space
between air nozzle orifice 49 and aspirator cap orifice 47 as shown
in FIG. 11.
In operation, with water or medicament placed in the nebulizer jar
16, air or oxygen enriched air is supplied via supply line 52 into
the interior of nozzle 44 where it is forced out of nozzle orifice
49. Depending on the liquid surface tension, water or medicament
will usually rise within channels 53 by capillary action thereby
pre-priming the system and improving its response time to
inspiratory gas flow. Because of the lower pressure provided in
mixing chamber 51 by the jet's stream of air escaping from nozzle
49, through the mixing chamber and out through aspirator cap
orifice 47, liquid within channels 53 will be drawn upwardly
therealong mixing chamber 51. The liquid is drawn into the mixing
chamber due to the partial vacuum created therein by the gas being
forced therethrough which partial pressure is lower than the
pressure on the surface of the liquid within the nebulizer jar and
is often referred to as the Venturi principle as will be
appreciated by those skilled in the art. Further, as the gas
escaping from nozzle orifice 49 contacts and mixes with the liquid
within mixing chamber 51, because of the gas velocity, small
droplets of the water or medicament will be formed in the form of
an aerosol or mist which will pass through restricted aspirator cap
orifice 47. Thereafter, observing further FIG. 10, the mist will
impinge on the lower surface of baffle 46 located directly above
aspirator cap orifice 47 and spaced therefrom and then be deflected
out into the interior chamber 45 of the nebulizer.
It will be noted that the liquid level within jar 16 should be
maintained below the horizontal plane of air nozzle orifice 49.
Should the liquid level be too high, the liquid level within the
channels would spill over the top of nozzle orifice 49, drain into
the interior of the air nozzle and into the oxygen or gas directing
tube 52 which is undesirable. For this purpose, a visible maximum
liquid level line or indicia may be scribed or molded on jar 16 for
observation by an operator to prevent filling the jar with too much
water or medicament. Further, since the manifold device of the
invention including the nebulizer jar are maintained along a
substantially vertical plane, even when in operation because of the
devices symmetry, the liquid level can be readily observed by an
operator whereas in other devices which are unbalanced and tilted
with respect to vertical, the liquid surface level may not be so
correctly observed relative to the scribed line on the nebulizer
jar.
Although a baffle 46 is optional, it will be preferred since it
assists further nebulization of the liquid particles impinging
thereon. Moreover, it will prevent unduly large particles from
entering main tube 12 of the manifold. Generally for most patients
receiving inhalation therapy requiring a mist or aerosol composed
of fine droplets of water or medicament in an air or oxygen
enriched air stream, particle sizes between about 2 and about 5
microns are preferred. Thus, by using a baffle in cooperation with
the spray orifice, larger particles will be further broken up as
they impinge against the baffle surface or will collect there. Such
particles or drops are then forced outwardly from the surface by
the forced gas and fall into the body of water or medicament within
the jar.
As shown, baffle 46 comprises a main body having extending
downwardly therefrom a plurality of arms 40 which are flanged on
the bottom. The flanged portion 59 extends inwardly and is
connected or attached to the exterior side of aspirator cap 42.
However, such construction is not particularly critical and other
means of employing a baffle and attaching it within the nebulizer
chamber may be used. However, again, the baffle is preferably
located so that the surface on which the nebulized mist is forced
from aspirator cap orifice 47 will impinge is located directly
above but separated from that orifice.
Observing again FIG. 12, aspirator cap 42 is shown as having its
interior side cut to provide four flattened surfaces which rest
against the circumferential exterior surface of air nozzle 44.
However, any number of such flattened surfaces may be formed on the
interior surface of the aspirator cap 42 to achieve the same
purpose and provide a like number of passageways for flow of the
medicament or liquid.
It has been found that the relationship of the relative sizes of
the air nozzle orifice and aspirator cap orifice as well as the
distance therebetween is an important feature of the invention to
achieve optimum aerosol characteristics. To achieve particles sizes
within the preferred range of between about 2 and about 5 microns
it has been found that the air nozzle orifice and aspirator cap
orifice should have diameters between 0.030 and 0.032 and 0.041 and
0.043 inch respectively. In addition, the distance between the
upper edge of the air nozzle orifice and lower edge of the
aspirator cap nozzle should be greater than the diameter of either
of the orifices and preferably about two times greater than the
diameter of the aspirator cap orifice. Although the improved
nebulizer is described herein for uses with the manifold it should
be appreciated that it may be used to provide an aerosol for other
inhalation therapy equipment such as oxygen masks, mouthpieces and
the like.
Various types of materials and preferably plastics may be used to
prepare the device of the invention. For example, the main manifold
tube and exhalation valve assembly may be formed of high impact
polystyrene, polyethylene and similar materials where visibility
through the parts is not critical. The nebulizer cap may also be
prepared of the same material. However, the nebulizer jar should
preferably be made of a clear plastic such as crystal styrene.
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