U.S. patent number 3,893,458 [Application Number 05/449,153] was granted by the patent office on 1975-07-08 for heat sterilizable patient ventilator.
Invention is credited to James C. Administrator of the National Aeronautics and Space Fletcher, Alexander S. Irons, Willie D. Kent, Paul P. Muehter, N/A.
United States Patent |
3,893,458 |
Fletcher , et al. |
July 8, 1975 |
Heat sterilizable patient ventilator
Abstract
An improved heat-sterilizable patient ventilator characterized
by a ported center-body, a shell formed of heat-sterilizable
material mounted on the center-body and defining an hermetically
sealed reservoir for confining under positive pressure a mixture of
bacteria-free gas, and a pneumatic circuit including an oxygen
delivery jet coupled with an absolute filtration system for
delivering bacteria-free mixture of gases to the reservoir.
Inventors: |
Fletcher; James C. Administrator of
the National Aeronautics and Space (N/A), N/A (La
Canada, CA), Irons; Alexander S. (La Canada, CA),
Muehter; Paul P. (Tujunga, CA), Kent; Willie D. |
Family
ID: |
23783078 |
Appl.
No.: |
05/449,153 |
Filed: |
March 7, 1974 |
Current U.S.
Class: |
128/204.25;
55/DIG.35; 128/205.29 |
Current CPC
Class: |
A61M
16/00 (20130101); A61M 16/1055 (20130101); Y10S
55/35 (20130101) |
Current International
Class: |
A61M
16/00 (20060101); A61M 16/10 (20060101); A61m
016/00 () |
Field of
Search: |
;128/142-142.3,145R,145.5-145.8,188,202,146.3,146.5,146.6,2.08,196,197,209,210
;55/DIG.35,DIG.33,485,486 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Assistant Examiner: Recla; Henry J.
Attorney, Agent or Firm: Mott; Monte F. Manning; John R.
Grifka; Wilfred
Government Interests
ORIGIN OF INVENTION
The invention described herein was made in the performance of work
under a NASA contract and is subject to the provisions of Section
305 of the National Aeronautics and Space Act of 1958, Public Law
85-568 (72 Stat. 435; 42 U.S.C. 2457).
Claims
What is claimed is:
1. In a heat-sterilizable patient ventilator of the type including
a ported center-body having means defining a circumscribing annular
shoulder, a shell mounted on said shoulder for defining in
juxtaposition with the center-body an hermetically sealed reservoir
for confining gas consisting essentially of a bacteria-free mixture
of ambient atmospheric gas and pure oxygen, and means for
discharging said mixture from said reservoir including a first
tubular gas conduit extended from said reservoir to a discharge
fitting, the improvement comprising:
means for delivering bacteria-free gas to said reservoir
including,
A. a second tubular gas conduit of relatively constant diameter
extending from said reservoir having means defining at one end
thereof a gas discharge port communicating with said reservoir and
means defining at the other end thereof an ambient gas intake port
remotely related to said gas discharge port;
B. filter means connected to the second tubular gas conduit at the
said other end thereof for substantially sealing said ambient gas
intake port against entry of microorganisms including:
1. a filter housing,
2. a dust filtration unit seated in said housing formed of Scott
filter foam,
3. a microbial filtration unit seated in said housing in
juxtaposition with said dust filter unit including a plurality of
screen-supported bacterial retentive pads formed of FM-004
fiberglass filter material, and
4. a media migration filtration unit seated in said housing in
juxtaposition with said microbial filtration unit formed of Scott
filter foam; and
C. means including a gas jet coaxially related to said second
tubular gas conduit for discharging into the second conduit a
stream of gas consisting essentially of pure oxygen.
2. The improvement of claim 1 wherein said patient ventilator is
fabricated from materials adapted to withstand heat of
predetermined temperatures for periods of predetermined durations
without experiencing substantial degradation.
3. The improvement of claim 1 further comprising filter means for
filtering bacteria from said stream of gas consisting essentially
of pure oxygen.
4. The improvement of claim 3 further comprising means for mounting
said shell in a substantially unstressed condition including means
defining a stud-receiving opening in said shell, a stud extended
through said opening having an annular shoulder disposed in
juxtaposition with said shell, a stand-off washer seated on said
shoulder and extended through said bore, and an O-ring
concentrically related to said stand-off washer for hermetically
sealing said bore.
5. The improvement of claim 4 further comprising means defining an
annular groove circumscribing the shoulder of said center-body, and
an O-ring seated in said groove in contiguous engagement with the
adjacent surface of said shell.
6. The improvement of claim 1 wherein said second tubular gas
conduit includes a venturi, the downstream end of which is disposed
in juxtaposition with said reservoir.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an intermittent positive pressure
breathing apparatus, herein referred to as a patient ventilator,
and more particularly to a heat-sterilizable patient ventilator
having an improved pneumatic circuit.
2. Description of the Prior Art
As a practical matter, non-heat sterilizable equipment often serves
as a source of many types of hospital-associated infections. Such
equipment frequently is rendered non-heat sterilizable as a result
of the materials employed in the construction of the equipment.
Chemical agents, of course, cannot always be relied upon to
sterilize equipment due to the inherent complexity of the
equipment, the types and numbers of microorganisms present, and
numerous other conditions indigenous to environments in which such
equipment is employed.
Patient ventilators are found to be among the most culpable devices
included in equipment having a propensity to foster propagation and
spread of infectious microorganisms. It is postulated that these
devices are particularly culpable because of their incompatibility
with sterilization processes which can be relied upon to effect a
complete removal or inactivation of associated infectious
microorganisms. Moreover, infectious microorganisms tend to
multiply quite rapidly within the humid environment normally found
within such devices. It can, therefore, readily be appreciated that
in the event a patient ventilator is incompletely sterilized, or
has been sterilized and subsequently receives a charge of
microorganisms, the device is capable of being contaminated rapidly
due to the rapid growth rate of the microorganisms.
A typical patient ventilator is illustrated in U.S. Letters Pat.
No. 3,068,856 which has been found adequate for many purposes.
Ventilators of the type illustrated in the aforementioned patent
can be adjusted to assist or control the rate and depth of
pulmonary ventilation. Both the inspiratory and the expiratory
phases of spontaneous respiration can be assisted by the ventilator
to increase the gas volume during inspiration and enhance the
outward flow of gases from the lungs of a patient during the
expiratory phase of a breathing cycle.
As described in the aforementioned patent, oxygen from a
pressurized tank enters the apparatus and is ducted to a
pressurized reservoir via a venturi. Unfortunately, it is difficult
to acquire bacteria-free oxygen from existing distribution systems.
Therefore delivery of bacteria-free oxygen to and beyond the
venturi of the patented ventilator cannot be guaranteed, simply
because bacteria-ladened oxygen is mixed with filtered ambient,
atmospheric gas from which particles, but not microorganisms, have
been removed. As a result, mixtures of bacteria-ladened gases are
delivered to the patients.
Sterilization of ventilators, of the type hereinbefore described,
requires a complete disassembly of all components and a
decontamination of each component with various chemical substances
that often are hazardous to both materials and to personnel. Of
course, the components must be reassembled in a bacteria-free
environment in order to assure that the sterilized condition of the
ventilator is maintained. Presently, facilities for reassembling
the ventilators in a bacteria-free environment generally are not
available. Moreover, once a ventilator of the type aforementioned
has been sterilized, further precautionary measures must be taken
to prevent microorganisms from again entering the ventilator. This
frequently necessitates the use of sterilized, hermetically sealed
storage containers.
Therefore, it can be appreciated that heretofore sterilization of
patient ventilators has been deemed to be an expensive process in
terms of the labor costs, the materials utilized, and the
facilities required in the sterilization and storage thereof.
It is therefore the general purpose of the instant invention to
provide a patient ventilator which is both heatsterilizable and
substantially impervious to microorganisms found in ambient
atmospheric air.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the instant invention to provide a
heat-sterilizable patient ventilator.
It is another object to provide a heat-sterilizable patient
ventilator which is impervious to microorganisms.
It is another object to provide a patient ventilator formed of heat
resistant material which can readily be packaged and then
sterilized in a fully assembled condition and readily stored in
such condition.
These and other objects and advantages are achieved through the use
of a heat-sterilizable patient ventilator which includes a ported
center-body including an annular shoulder, a shell formed of a heat
resistant material seated on the shoulder and defining in
juxtaposition with the center-body an hermetically sealed reservoir
for confining under positive pressure a bacteriafree mixture of
ambient atmospheric gas and/or pure oxygen, a discharge conduit
extended from the reservoir to a discharge fitting adapted to be
received by a patient, and an absolute filter system for delivering
bacteria-free gas to the reservoir, as will become more readily
apparent by reference to the following description and claims in
light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-sectional view of a heatsterilizable
patient ventilator which embodies the principles of the instant
invention.
FIG. 2 is a cross-sectional view taken generally along line 2--2 of
FIG. 1.
FIG. 3 is a sectional view taken generally along line 3--3 of FIG.
2, illustrating an arrangement of studs provided for securing a
closure shell to the center-body of the patient ventilator.
FIG. 4 is a fragmented, partially sectioned view of an end portion
of one of the studs shown in FIG. 3.
FIG. 5 is a cross-sectional view of a first absolute filter
provided for filtering ambient atmospheric air as it is delivered
to the patient ventilator.
FIG. 6 is an exploded view of a support ring employed in supporting
bacteria retentive pads provided for the filter shown in FIG.
5.
FIG. 7 is a cross-sectional view of a second absolute filter
provided for filtering oxygen as it is delivered to the
ventilator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, with more specificity, wherein like
reference characters designate like or corresponding parts
throughout the several views, there is shown in FIG. 1 a
heat-sterilizable ventilator, generally designated 10, which
embodies the principles of the instant invention.
The ventilator 10 is provided with a center-body 12, preferably
machined from a suitable aluminum casting. As a practical matter,
the center-body 12 is of a type similar to the center-body shown
and described in the aforementioned U.S. Letters Pat. No.
3,068,856. The center body 12 includes a vertically oriented oxygen
conduit 14 through which pure oxygen is delivered to the patient
ventilator. The conduit 14 is provided with a bi-stable valve 16
for controlling the flow of oxygen therethrough. Where desired, the
valve includes a spool seated in a sleeve having appropriate,
radially extended passages, not shown. An axially movable,
valve-actuating shaft 18 is integrally connected with the spool and
terminates at its opposite ends in armatures 20. The shaft 18
serves to switch the valve 16 between its bi-stable conditions as
appropriately directed, axial motion is imparted thereto. An
axially adjustable magnet assembly 22 is supported in juxtaposition
with each of the armatures 20 and serves to assist in imparting
axial motion to the shaft and to retain the shaft in a position to
which it is advanced. It is to be understood that when the shaft 18
is moved in a first direction, the valve 16 is opened so that a
flow of oxygen under pressure is established through the oxygen
conduit 14; when the shaft 18 is moved in an opposite direction,
the valve 16 is closed for thereby interrupting the flow of oxygen
established through the conduit 14.
Also mounted on the shaft 18 there is a diaphragm 24 formed of
silicone rubber having its peripheral surfaces hermetically sealed
about a recess machined in one surface of the center-body for thus
defining an expansible plenum chamber 26 whereby the shaft is
advanced in opposite directions in response to changes in pressure
within the plenum chamber.
The center-body 12 is provided with an annular shoulder 30 which
serves as an annular seat for receiving a shell 32 in a mated
relation for thus establishing an hermetically sealed reservoir 34
adjacent to the center-body 12. The shoulder 30 is provided with an
annular groove within which there is seated an O-ring 36, also
formed of silicone rubber, for thus establishing an hermetic seal
between the adjacent surfaces of the shell 32 and the shoulder 30,
without subjecting the shell to significant stress. It is important
here to note that the shell 32 is formed of a material which will
not degrade when exposed to heat-sterilization cycles,
characterized by temperatures of 257.degree. F. and a duration of
approximately 6 hours. Since the material employed preferably is
susceptible to molding, polysulfone serves quite satisfactorily for
this purpose.
The shell 32 further serves as a mount for one of the magnet
assemblies 22. Further, the shell is provided with a flow discharge
port 38 connected with a conduit 40 through which a mixture of
ambient atmospheric gas and oxygen is discharged from the reservoir
34 through a humidifier 42, to a fitting 44 adapted to be received
within the mouth of a patient, not shown.
The humidifier 42, as a practical matter, is an in-line nebulizer,
of a known configuration, which serves to deliver to the mixture of
gases flowing through the conduit 40 an atomized liquid.
Additionally, where so desired, a micronebulizer 46 is connected
with the conduit 40 and serves to deliver medication to the mixture
of gases passing to the mouthpiece or fitting 44. Of course, the
conduit 40, the humidifier 42 and the nebulizer 46 also are formed
from material which will not degrade during sterilization cycles.
Where desired, the case for the humidifier 42, as well as the
nebulizer 46, is formed of polysulfone, while the conduit is formed
of Silastic tubing.
The fitting 44 includes an exhaust valve 48 normally maintained in
a sealed condition through back pressure developed in a plenum
chamber 50 connected with the oxygen conduit 14 through a pressure
tube 52, also formed of Silastic rubber. The exhaust valve 48
includes a compression spring 54 acting on a closure plate 56 for
closing an exhaust port, not designated. It is to be understood
that the compression spring 54 permits the sealing plate 56 to be
displaced as a patient exhales, or coughs, for discharging spent
gas through a discharge orifice 58.
Moreover, the pressure tube 52 also serves to deliver oxygen under
pressure to the in-line nebulizer 46 through a branch tube 60. This
tube is connected between the nebulizer and the pressure tube 52,
and serves to deliver a pressurized stream of oxygen to the
nebulizer in a manner well understood by those familiar with such
devices. Accordingly, a more detailed description of the nebulizer
46 is omitted in the interest of brevity.
Turning now to FIGS. 2, 3 and 4, it can be appreciated that the
shell 32 is mounted by a plurality of studs 61 connected with the
shell in a manner such that the shell remains in a substantially
unstressed condition. The studs 61 are secured within the
center-body 12, in any suitable manner and project in opposite
directions therefrom. Each stud includes a distal portion 62 which
includes an annular shoulder 64, FIG. 4. Seated on each of the
shoulders 64 there is a stand-off washer 66 having a tubular body
68 and a radially extended flange 70. The tubular body 68 is
received within a bore 72 formed in the shell 32, so that the shell
is permitted to seat on the flange 70. Preferably, an O-ring 74
also is mounted on the body 68 and seats against the external
surface of the shell 32. A conventional washer 76 seats on the
O-ring 74 while a nut 78 is threaded onto the distal end portion of
the stud 61, whereupon the O-ring 74 is crushed for thus forming an
hermetic seal between the bore 72 and the stand-off washer 66.
Consequently, the nut 78 can be suitably torqued without
introducing stress in the shell 32. This, of course, tends to
obviate deformation and crazing when the ventilator is subjected to
a heatsterilization cycle.
The reservoir 34 communicates with the plenum chamber 26 through a
plurality of pressure equalizing bores 80 through which pressures
established within the plenum chamber and the reservoir are
substantially equalized. As a practical matter, it should be
apparent that so long as gas is extracted from the reservoir 34,
via the fitting 44, pressure within the plenum chamber 26 is
reduced and the valve 16 remains open. However, in the event
pressure within the reservoir 34 is elevated, via the bores 80,
sufficiently for expanding the plenum chamber 26, the diaphragm 24
is displaced for repositioning the shaft 18 whereupon valve 16
closes. The magnet assemblies 22 serve to insure a complete
repositioning of the shafts 18 as the armatures 20 are alternately
positioned within the flux fields of the magnet assemblies for thus
assuring a seating of the shaft 18 in either of its alternate
positions as it comes to rest following axial displacement.
As a practical matter, the center-body 12 is provided with an
additional bore 82, downstream from the valve 16, through which the
conduit 14 communicates directly with the reservoir 34 for metering
pure oxygen to the reservoir, whereby an elevated pressure is
developed within the reservoir at any time the valve 16 is opened.
Hence, it should be appreciated that the valve 16 is a normally
closed valve.
As a practical matter, a shell 84 is mounted on the center-body 12
in a manner quite similar to that in which the shell 32 is fixed to
the center body. However, it is important to note that the shell 84
merely serves as supporting structure for a magnet assembly 22.
Therefore, it is to be understood that the shell 84 need not be
hermetically sealed relative to the center-body.
It is here important to note that ambient atmospheric gas is
introduced into the reservoir 34 via a filtration system generally
designated 90. The filtration system 90 includes a conduit 92 which
extends through the center-body 12 and terminates in a flow control
valve 94. The flow control valve 94 includes a ported housing 95
having formed therein a multiplicity of radially extended ports 96.
A spring-loaded closure plate 98, biased by a spring 99, is seated
in the housing and closes the valve by seating against the adjacent
end surface of the conduit 92. It will therefore be appreciated
that as pressure within the conduit 90 is caused to exceed the
combined forces of the spring 99 and pressure established within
the reservoir 34, the plate 98 lifts off its seat against the bias
of its spring for opening the ports 96.
As should readily be understood by those familiar with the
administration of oxygen to patients, it is necessary that oxygen
rich gases delivered to a patient should be so mixed as to include
approximately 85 percent ambient atmospheric air in order to avoid
various undesirable side effects. Therefore, the opposite end of
the conduit 92 is connected with an absolute filter 100, through
which ambient atmospheric gas is introduced to the patient
ventilator. Consequently, it is necessary that the filter 100 have
a capacity which accommodates such requirements. Moreover, patients
being treated frequently are in a debilitated condition which
requires that the ambient atmospheric air be readily conducted
through the filter in order to sustain respiration with minimal
effort. Thus, the filter 100 must also possess a capacity for
accommodating passage of atmospheric gas in the presence of a
minimal pressure differential established thereacross.
The filter 100 is provided with a filter housing 102, also formed
of a heat-sterilizable material such as polysulfone. Within the
housing 102 there is seated, in series, a dust filter unit 104 upon
which is seated a microbial filtration unit 106, and a media
migration filter unit 108, seated, in turn, upon the microbial
filter unit 106. The dust filtration unit 104 preferably is formed
of a fine open-pore urethane foam, such as that developed by the
Foam Division of the Scott Co., Chester, Pennsylvania, which
removes particulate matter from ambient atmospheric gases as it
enters the filter 100 via an entrance port 110. This unit is
sustained in position through a support ring 112 seated on an
annular lip 114 circumscribing the entrance port 110. As a
practical matter, the support ring 112 is of an annular
configuration with the midportion thereof being closed by a screen
116 of any suitable mesh affixed thereto.
The microbial filter unit 106 includes a plurality of bacteria
retentive pads 118, each of which is supported by a support ring
112. As a practical matter, each of the support rings 112 is
provided with a plurality of spacer pins 120 which prevent the pads
118 from being crushed between the support rings 112. The pads 118
are formed from filter material, preferably a very fine spun glass
material such as that designated FM-004 and manufactured by
Owens-Corning Fiberglas Corp., Toledo, Ohio. This material is known
to have a capability for removing all bacteria from gases passing
therethrough.
The media migration filter unit 108 also is formed of open-pore
urethane foam and serves to assure that no particles of the
fiberglass material which becomes disassociated from the pads 118
is permitted to pass from the filter 100 to the conduit 92. Once
ambient atmospheric gas is drawn through the filter 100, it is
delivered to the valve 94, via a venturi throat 122 having its
downstream end communicating with the reservoir 34, via the ports
96. The purpose of the venturi 122 is to achieve a mixing of pure
oxygen with ambient atmospheric gas prior to an introduction of
resulting mixture into the reservoir 34.
In order to achieve a mixing of pure oxygen with the ambient
atmospheric gas, within the venturi 122, there is provided an
oxygen jet 124 mounted at the distal end of a tubular conduit 126
which, in turn, is connected with the oxygen conduit 14 and
communicates therewih through a port 128. The jet 124 is located
immediately upstream from the entrance to the venturi 122 and is
disposed in coaxial alignment therewith. The jet 124 serves to
direct a stream of pure oxygen, derived from the oxygen conduit 14,
axially into the throat of the venturi 122 whereupon a mixing of
the oxygen with ambient atmospheric gas delivered through the
conduit 92 is effected prior to its being discharged into the
reservoir 34.
In order to control the rate of flow of oxygen through the oxygen
conduit 14, there is provided a flow-rate valve 130 having a
tubular body 132 within which there is provided a plurality of
ports 134. The body 132 is supported by a suitable boss 136 while
the ports 134 are axially spaced at distances such that they become
aligned, simultaneously, with the opening for the bore 82 and the
conduit 126, as the body is advanced through the boss 136. Thus,
the flow of oxygen through the flow-rate valve 130 can be
controlled by axially displacing the body 132. Consequently, while
it is preferable to administer to a patient gases consisting of 85
percent ambient atmospheric air, the ratio of oxygen gas to ambient
atmospheric gas can be varied where so desired.
Of course, as hereinbefore mentioned, it is difficult to acquire a
practical source of bacteria-free oxygen, therefore, a filter 138
is provided between the oxygen conduit 14 and a selected source of
oxygen, not shown. The purpose of the filter 138 is similar to that
of the filter 100 in that this filter is an absolute filter
provided for removing microorganisms inherently present in oxygen
commonly found in distribution systems. The filter 138 includes a
heat-sterilizable housing 160 capable of withstanding pressures of
at least 60 p.s.i. Within the housing there is provided a filter
unit formed of alternating filter pads 162 and 164. The pads 162
also are formed of fine open-pore urethane foam, similar to
material employed in fabricating the dust filter unit 108, while
the pads 162 are formed from spun glass material similar to the
material employed in the pads 118. It should therefore be apparent
that through the filter 138 it is assured that the oxygen
introduced into the patient ventilator is introduced in a
bacteria-free condition.
The housing 160 is closed at each of its opposite ends by ported
end plates 170 and 172. The end plate 170 includes a fitting 174
for coupling the filter to a source of oxygen while the end plate
172 includes a fitting 176 for connecting the filter to the conduit
14.
OPERATION
It is believed that in view of the foregoing description, the
operation of the device will readily be understood and it will be
briefly reviewed at this point.
Assuming that the pressure within the reservoir 34 is maximized, it
can be appreciated that the pressure within the plenum chamber 26
also is maximized so that the valve 16 is in an "off" condition.
Similarly, the plate 98 of the valve 94 is seated in sealing
relation with the adjacent end of the conduit 92. A patient may now
insert the fitting 44 into his mouth and begin inhalation. As the
patient inhales, pressure is reduced within the reservoir 34 so
that the plate 98 unseats with respect to the distal end of the
conduit 92 and the diaphragm 24 begins to collapse, due to the
reduction of pressure within the plenum chamber 26. Thus, movement
of the shaft 18 is initiated for switching the valve 16 to its "on"
condition, whereupon a stream of oxygen is established through the
filter 138 and the oxygen conduit 14. The gas of this stream
rendered bacteria-free by the filter 138 is discharged into the
reservoir 34, via the bore 82, and into the conduit 92, via the jet
124. As the patient continues to inhale, ambient atmospheric air is
drawn through the filter 100 of the dust filtration unit 104,
whereupon foreign particles are removed therefrom. As the ambient
atmospheric gas advances through the filter, it is passed through
the microbial filtration unit whereupon all microorganisms are
extracted therefrom. The ambient atmospheric air then continues
through the final media migration filtration unit whereupon all
foreign particles finally are removed from the gas, particularly
particles of fiberglass wool which may have become suspended in the
gas as it is passed through the microbial filtration unit.
The gas then passes from the filter to the venturi 122, through the
conduit 92, and is there mixed with oxygen delivered from the jet
124, and thereafter passed to the reservoir 34. Gas thus passed to
the reservoir 34 is delivered via the conduit 40 through the
humidifier 42 and the nebulizer 46 to a patient, at the fitting 44.
Of course, once inhalation is completed and exhalation is initiated
a back pressure develops within the reservoir 34 causing the plate
98 to reseat at the distal end of the conduit 92 and the plenum
chamber 26 again to be pressurized for switching the valve 16 to
its off condition. As the patient exhales, the plate 56 of the
fitting 44 is unseated, against the compression spring 54, so that
the discharge orifice 58 is open. Thus, the patient normally
discharges the air confined within his lungs to ambient
atmosphere.
it should here be noted that the filtration system 90 is completely
sealed against an introduction of microorganismbearing gas. Thus,
the only opening through which contamination of the patient
ventilator is accommodated is the fitting 44. Since the fitting 44
can readily be sealed by a suitable bag or similar structure
attached thereto, it is possible to store the ventilator 10 in a
completely sterile condition.
A desired sterile condition is readily achieved simply by
subjecting the assembled patient ventilator 10 to a temperature
suitable for destroying microorganisms contained therewithin. Since
the various components of the patient ventilator are formed of
materials readily adapted to withstand the required temperatures,
the patient ventilator can be sterilized and stored in only a
fraction of time heretofore required, and stored in a practical and
economic manner.
In view of the foregoing, it should readily be apparent that the
ventilator of the instant invention provides a practical solution
to the perplexing problem of avoiding an introduction of infectious
organisms into patients as they are treated employing a patient
ventilator.
Although the invention has been shown and described in what is
conceived to be the most practical and preferred embodiment, it is
recognized that departures may be made therefrom within the scope
of the invention, which is not to be limited to the illustrative
details disclosed.
* * * * *