U.S. patent application number 11/467255 was filed with the patent office on 2007-10-04 for method and device for collecting and analyzing exhaled breath.
This patent application is currently assigned to Respiratory Research, Inc.. Invention is credited to Alfred R. Baddour.
Application Number | 20070232952 11/467255 |
Document ID | / |
Family ID | 29270277 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070232952 |
Kind Code |
A1 |
Baddour; Alfred R. |
October 4, 2007 |
Method and Device for Collecting and Analyzing Exhaled Breath
Abstract
A method and device for collecting, storing, shipping, preparing
and analyzing condensate derived from the exhaled breath of a user.
Using the mouthpiece (15) of the device (10), a human subject
inhales drawing air through a check valve (30).
Inventors: |
Baddour; Alfred R.; (Austin,
TX) |
Correspondence
Address: |
WOODS, ROGERS, P.L.C.
1505 LONDON ROAD
CHARLOTTESVILLE
VA
22902-8681
US
|
Assignee: |
Respiratory Research, Inc.
Charlottesville
VA
|
Family ID: |
29270277 |
Appl. No.: |
11/467255 |
Filed: |
August 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10257912 |
Oct 17, 2002 |
7118537 |
|
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11467255 |
Aug 25, 2006 |
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Current U.S.
Class: |
600/543 ;
600/532 |
Current CPC
Class: |
A61B 5/082 20130101 |
Class at
Publication: |
600/543 ;
600/532 |
International
Class: |
A61B 5/08 20060101
A61B005/08 |
Claims
1) A portable device for collecting, sporting, storing and
processing condensate from air exhaled thereinto comprising: a
mouthpiece having three projections by means of which air is
inhaled and exhaled; an optional filter housing having two openings
separated by a filter assembly the first one of which is
interconnected with a first projection of said mouthpiece; a hollow
condensate collecting tube having two open ends and a circular
cross-section interconnected at a first open end with the second
opening of said filter housing; movable valve means deformable and
sealingly inserted between the interior walls of said collecting
tube near the first open end thereof for preventing the admission
of air during inhalation; admitting exhaled air into said
collecting tube, making airflow therethrough turbulent, swiping
condensate off the interior walls of said collecting tube,
preventing efflux of condensate, retaining the condensate in a pool
and channeling gasses or liquids into the condensate; hollow
removable cooling sleeve means slidably placed over said collecting
tube wherein said cooling sleeve means has an interior diameter
only slightly greater than the exterior diameter of said collecting
tube so that the interior walls of said cooling sleeve means are in
at least close physical proximity to the exterior walls of said
collecting tube for drawing heat from the inner surface of said
collecting tube to accelerate the condensing process; and
advancement means removably insertable into the first open end of
said collecting tube behind said valve means for pushing said valve
means upwards towards the second open end of said collecting
tube.
2) The device of claim 1 wherein carbon dioxide is removed from the
condensate preparatory to testing the acidity level of the
condensate by channeling one or more gases through said valve means
into the condensate.
3) The device of claim 2 wherein the gas channeled through said
valve means is one or more selected from argon, helium, oxygen or
air that has had carbon dioxide removed from it with a carbon
dioxide trap.
4) The device of claim 1 further including airtight cap means for
providing a removable seal over the second open end of said
condensate collecting tube after removal of said advancement means
from said collecting tube prior to storage and/or shipment to
another location.
5) The device of claim 1 wherein a second projection of said
mouthpiece includes check valve means for admitting air during
inhalation and inhibiting the egress of air during exhalation
6) The device of claim 1 wherein said valve means has valve leaves
and a generally elliptical cross-section which is deformed into a
circular shape upon insertion into said collecting tube.
7) The device of claim 6 wherein by deforming said valve means a
complete seal is created between the valve leaves.
8) The device of claim 7 wherein said valve means is generally
hollow and includes an upper section of lesser mass and a lower
section of greater mass and wherein the boundary between the upper
and lower sections is generally defined and separated by one or
more pairs of hollow passageways formed in the body of said valve
means each of which passageways extends from near the bottom of the
hollow interior of said valve means diagonally upward to the
exterior of said valve means exiting into a generally semi-circular
notch formed at a point above the bottom of said valve means
displaced between approximately one-eighth and one-quarter of the
length of said valve means away from the bottom thereof
9) The device of claim 8 wherein resilient ring means are seated in
the notch in said valve means for maintaining said valve means in
an orthogonal orientation with the interior walls of said
collecting tube, for wiping the inner walls of said collecting tube
as said valve means is pushed upwardly therethrough and for
deflecting in reaction to force exerted upon it by a pressurized
substance flowing through the hollow passageways within said valve
means.
10) The device of claim 1 wherein said cooling sleeve means has a
lower temperature than said collecting tube.
11) The device of claim 10 wherein said cooling sleeve means tends
to maintain a low temperature.
12) The device of claim 11 wherein said cooling sleeve is comprised
of aluminum.
13) The device of claim 11 wherein said cooling sleeve is comprised
of a material having a high specific heal
14) The device of claim 1 wherein said cooling sleeve is between
approximately one-quarter and one-half inch shorter than said
collecting tube.
15) The device of claim 1 further including degassification means
for forcing pressurized gas through the condensate.
16) The device of claim 15 wherein said degassification means is a
physical probe which is inserted into the open bottom end of said
collecting tube and extended therethrough until brought into
physical contact with the bottom of said valve means.
17) The device of claim 15 wherein said degassification means is a
single positively pressurized manifold into which the open bottom
end of said collecting tube is retainably inserted and through
which said collecting tube is maintained in a vertical
position.
18) The device of claim 15 wherein said degassification means
comprises a first manifold into which the open bottom end of said
collecting tube is retainably placed and a second manifold into
which the open top end of said collecting tube is retainably placed
wherein both ends of said collecting tube are subjected to a
mechanized vacuum and wherein further said second manifold is
periodically opened to atmospheric pressure.
19) The device of claim 1 wherein the structure of said mouthpiece
substantially reduces the number of salivary droplets which are
exhaled by a subject from entering said optional filter housing or
said collecting tube.
20-27. (canceled)
28. A device for collecting condensate from breath exhaled
thereinto comprising: mouthpiece means for admitting and directing
both inhaled and exhaled breath; a hollow condensate tube having
two open ends connected on one end to said mouthpiece means;
movable valve means sealingly inserted between the interior walls
of said tube for preventing the admission of air during inhalation,
controlling the admission of exhaled breath into said tube during
exhalation and swiping condensate off the interior walls of said
tube as it is moved along said tube.
29. The device of claim 28 wherein said valve means further makes
airflow through said tube turbulent, prevents efflux of condensate,
retains condensate in a pool and channels gasses or liquids into
the condensate.
30. The device of claim 28 further comprising cooling means for
cooling said tube and for accelerating the formation of
condensate.
31. The device of claim 30 wherein said cooling means further
comprises a pre-chilled hollow, tubular sleeve placed in close
physical proximity to the exterior walls of said tube.
32. The device of claim 31 wherein said cooling means is
constructed from aluminum or any high specific heat, durable,
reusable material which does not deteriorate when wet and tends to
retain and maintain a low temperature when cooled.
33. The device of claim 31 wherein said cooling means is a
container in which chemicals can be mixed that create an
endothermic reaction.
34. The device of claim 28 further comprising advancement means for
causing said valve means to move from one end of said tube to the
other.
35. The device of claim 34 wherein said advancement means is a rod
and piston arrangement.
36. The device of claim 28 wherein said tube is constructed from
one or more of the group of materials consisting of plastic,
stainless steel, anodized aluminum, and Teflon.RTM..
37. The device of claim 28 wherein said valve means is constructed
from one or more of the group of materials consisting of rubber,
rubber-like elastomeric materials, and plastics which behave as
elastomers.
38. The device of claim 28 wherein the device is disposable.
Description
TECHNICAL FIELD
[0001] The subject invention relates generally to a method and
device for determining medical conditions, and, more particularly
to a method and device for condensing, storing, transporting,
degassing and analyzing exhaled breath.
BACKGROUND OF THE INVENTION
[0002] Recent medical research indicates that human airway acidity
and ammonia levels may be indicative of several events including
the onset of asthmatic symptoms. Furthermore, this research
indicates that the acidity measurements taken from a condensed
sample of exhaled breath can be correlated to the actual conditions
inside the airway.
[0003] Many known devices for collecting condensate from a user's
breath rely on gravity to form a condensate pool from which a
sample for testing may be drawn. These types of devices require
that condensate droplets become large enough to overcome water's
naturally tendency to stick to the walls of a collecting tube.
Then, when the amount of condensate eventually becomes large
enough, a risk of loss of collected condensate sample through
seepage out of the collection area may arise due to ineffective
sealing of the collection area. Even when an adequate condensate
sample had been collected, a risk of contamination occurred due to
the necessity to transfer the sample from a collecting tube into
test tubes or test devices. Moreover, where the collecting tube is
not cooled in some way, condensate formation takes an inordinate
amount of time. In some cases, the collecting tube is inserted into
an ice bucket or may even be separately cooled by refrigeration
systems in order to increase the amount and speed of condensate
formation. In other cases, use of a Teflon.RTM. collecting tube has
been tried to make the tube walls more slippery to enhance the
speed and amount of condensate collected. All of these arrangements
tend to be either expensive, complicated, ineffective, bulky,
inefficient or time-consuming to use. In addition, other condensate
collecting and testing devices generally do not provide the ability
in a single device both to quickly and efficiently collect
condensate while also delivering test substances such as gases or
liquids into the condensate without contamination. Moreover, such
devices are not typically portable and do not lend themselves
easily to use by patients in their own homes. Another disadvantage
of devices of the prior art is that they usually do not enable
patients to collect condensate samples, prepare those collected
samples for testing and then also perform certain tests themselves
on the samples.
[0004] What is needed is a device and method for condensate
collection which solves the problems and shortcoming already
described and, in addition, collects a greater amount of condensate
from a given amount of exhaled breath in a shorter time than
previously possible while also advancing the art by providing a
multi-functional valve for use in such a condensate collection
device that simultaneously assists in solving several of those
problems.
SUMMARY OF THE INVENTION
[0005] The present invention relates to a device and method for
collecting condensate from air exhaled by a subject user. The
device comprises a mouthpiece, a filter housing, a hollow
condensate collecting tube, a movable valve inserted within the
collecting tube, a cooling sleeve for placement over the collecting
tube, means for moving the valve through the collecting tube and a
removable airtight cap. In order to practice the method employing
the device, the cooling sleeve is cooled to a temperature lower
than that of the collecting tube prior to being slid thereover, air
is inhaled by a subject user through the mouthpiece and exhaled
through the movable valve into the collecting tube. After the
passage of between about two and twenty minutes of breathing, the
cooling sleeve is removed from around the collecting tube, the
movable valve is advanced through the tube thereby wiping away
condensate formed on the interior walls of the tube causing that
condensate to collect in a pool around the valve. Thereafter, an
airtight cap may be placed over the end of the collecting tube
nearest the condensate pool in order to seal the collecting tube
prior to storage and/or shipment to a testing location. At the test
location, the airtight cap is removed and one or more gasses or
liquids is introduced into the condensate through the unique
structure of the valve as called for by the particular test to be
performed on the condensate. In one embodiment of the device, gas
is introduced into the condensate in order to remove carbon dioxide
and permit the acidity level of the condensate to be reproducibly
measured. Testing may be performed after removing samples of the
condensate from the collecting tube or by means of a probe placed
into contact with the condensate pool or by insertion of chemicals
or chemically impregnated strips.
[0006] It is a primary objective of this invention to provide a
simple self-contained and portable device for efficiently
collecting, storing and shipping condensate derived from the
exhaled breath of a subject wherein the wettable components of such
a device may be disposable.
[0007] An additional objective of this invention is to provide a
method for collecting condensate derived from the exhaled breath of
a subject which is fast, simple, efficient and performable by
nonprofessional personnel.
[0008] A further objective of this invention is to provide a device
and method in which condensate samples collected from the exhaled
breath of a user may be both collected and subjected in situ to
various laboratory tests, including ones for measuring pH levels,
without the risk of contamination by exposure to influences
external to a collecting tube.
[0009] A yet additional objective of this invention is to provide a
condensate collecting device which may be made available for use in
a patient's home or workplace.
[0010] It is still another objective of this invention to provide a
device and multiple methods for removing carbon dioxide from
condensate collected from the exhaled breath of a subject
preparatory to measuring the acidity of such condensate.
[0011] It is yet a further objective of this invention to provide a
multipurpose valve structure having a unique elliptical shape for
use within a tube for collecting condensate from the exhaled breath
of a subject which makes the collection of condensate more
efficient and also assists in preparing the collected condensate
for laboratory testing.
[0012] It is another objective of this invention to provide a
device for degassing and/or for adding one or more gasses, liquids
or other materials to a sample of condensate collected from the
exhaled breath of a subject prior to or while performing laboratory
tests on that sample.
[0013] A further objective of this invention is to provide a device
in which condensate may be collected, stored and transported in a
single unit.
[0014] Still another objective of this invention is to provide a
condensate collecting device which makes septuple use of a valve
within the device for preventing the admission of air from a
condensate collecting tube during inhalation, admitting exhaled air
into the condensate collecting tube, making airflow turbulent,
swiping condensate off the interior walls of the tube, preventing
efflux of condensate, retaining the condensate in a pool within the
tube and channeling gasses or liquids into the condensate.
[0015] Yet another objective of this invention is to provide a
simple and efficient method for deaerating or degassing collected
condensate.
[0016] Still a further objective of this invention is to provide a
malleable duckbill valve having an elliptical cross-section for
placement within a non-malleable tube having a circular
cross-section so that a seal is made in the duckbill valve without
a pressure gradient across the valve.
[0017] A yet additional objective of this invention is to provide a
one-way malleable duckbill valve for placement within a condensate
collecting tube which encourages turbulent airflow as a subject's
exhaled breath passes through.
[0018] Another objective of this invention is to provide a hollow
duckbill valve permitting a mechanical seal to be obtained between
the valve and the nose portion of a probe inserted into the hollow
center of the valve.
[0019] Yet a further objective of this invention is to provide a
hollow duckbill valve incorporating one or more passageways through
which gasses or fluids will flow when the valve is subjected to
particular mechanical stresses.
[0020] An additional objective of this invention is to provide a
device with built-in protection for passersby against possible
release into the atmosphere of microbes from the lungs of the user
of the device.
[0021] These and other objects, features and characteristics of the
present invention, as well as the methods of operation and
functions of the related elements of structure and the combination
of parts and economies of manufacture, will become more apparent
upon consideration of the following description and the appended
claims with reference to the accompanying drawings, all of which
form a part of this specification, wherein like reference numerals
designate corresponding parts in the various figures. It is to be
expressly understood, however, that the drawings are for the
purpose of illustration and description only and are not intended
as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a center cross-sectional view of the device of the
invention;
[0023] FIG. 2 is a center cross-sectional view of the individual
components of the device of the invention in a disassembled
state;
[0024] FIG. 3 is a center cross-section view of the duckbill valve
of this invention before insertion into a collecting tube along a
plane perpendicular to the walls of a collecting tube;
[0025] FIG. 4 is a center cross-sectional view of the duckbill
valve of this invention along line A-A of FIG. 3;
[0026] FIG. 5 is a side view of the duckbill valve of this
invention;
[0027] FIG. 6 is a center cross-sectional view of a collecting tube
into which a probe has been inserted behind a duckbill valve.
[0028] FIG. 7 is a center cross-sectional view of a collecting tube
into which gas has been introduced under pressure to degas/deaerate
condensate;
[0029] FIG. 8 is a schematic of equipment used in performing a
second method of degassing/deaerating.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The device of the invention is intended to be used to
condense the water normally exhaled in breath by a human subject
and to gather this water in such a manner and in such volume that
tests may be performed on the condensate. These tests include
measuring acidity, ammonia concentration, as well as the
concentration of other characteristics, chemicals and compounds of
biologic interest. It may be used by an unskilled layperson, then
sealed for transport to a laboratory where subsequent analysis may
be performed. Alternatively, the device may also function as part
of a home- or workplace-diagnostic device constructed to accept the
device and perform the required measurements automatically.
Additionally, it may be used in any setting without additional
devices, by adding chemical reagents or test strips to detect
chemical features and compounds of interest.
[0031] For a better understanding of the invention, reference is
now made to FIG. 1 of the drawings. This figure illustrates a
center cross-sectional view of invention device 10 in a dormant
state prior to use. Device 10 may be assembled manually from
several principal components either before use or on site.
Mouthpiece 15 may be a generally tubular T-shaped device with three
open projections. On one end, mouthpiece 15 has a generally oblong
projection 20 designed to be comfortably inserted between a subject
user's lips. The opposite end projection 25 may be generally
tubular in shape, is open to the atmosphere and includes a check
valve 30 situated nearby for admitting ambient air from the
atmosphere through projection 25 into a subject user's mouth and
lungs and for preventing an outflow of air through projection 25
during the exhalation process.
[0032] Projection 35 is sized so as to be removably insertable into
one end of optional filter housing 40 and to be retained therein by
virtue of friction between the walls of the exterior of projection
35 and the walls of the interior of the end of filter housing 40
into which it is inserted. Alternatively, projection 35 can be
placed in direct intimate contact with the inner or outer surface
of collecting tube 60, and retained there by virtue of friction.
During exhalation by the subject user, check valve 30 closes and
forces exhaled breath to flow through projection 35.
[0033] Optional filter housing 40 may comprise a tube-like
structure open on both ends and having a filter compartment
disposed in the approximate middle thereof separating the two
openings 45 and 50 of the tube. Opening 45 on one end of filter
housing 40 is sized so as to receive projection 35 from mouthpiece
15. Optional filter housing 40 includes an optional filter assembly
55. In the preferred embodiment, the filter compartment and filter
are circular and have a diameter of approximately four times the
diameter of opening 50, although other configurations and relative
dimensions may be used. Different pore size of the filter might be
chosen to limit passage of particles to sizes of particular
interest. As particle size might relate to site of formation or
other features relevant to the airway, this optional filtering is a
useful feature. Optional filter assembly 55 in general functions to
remove larger particles from exhaled breath prior to its entering
collecting tube 60 and, depending on the filter chosen, also serves
to prevent egress of infectious particles in the atmosphere during
exhalation. This feature protects passersby from microbes possibly
release from the lung of a subject during use of the device. The
structure of mouthpiece 15 serves a similar function by
substantially reducing the number of salivary droplets which enter
optional filter housing 40 or collecting tube 60.
[0034] Collecting tube 60 is a straight plastic tube open on both
ends with a circular cross-section and may have a length of between
approximately 3 inches and 20 inches, preferably about 8.75 inches,
and a diameter of approximately 1/2 inch and at most approximately
2 inches, preferably about 0.875 inches. With tubes smaller than
1/2 inch in diameter, exhaling becomes difficult for the subject
user, while with tubes larger than 2 inches in diameter,
condensation efficiency is low. Regardless of the exact dimension
used, the diameter of collecting tube 60 may be slightly smaller
than that of opening 50 in filter housing 40, or alternatively
smaller than that of projection 35, so as to fit retentively within
the corresponding neck of filter housing 40 encompassing opening 50
or within projection 35. Alternatively, the diameter of collecting
tube 60 may be slightly larger than that of opening 50, or
projection 35, so that the neck of filter housing 40 including
opening 50, or alternatively projection 35, may be securely and
retentively inserted inside one end of collecting tube 60.
Collecting tube 60 may also be constructed from other materials
such as stainless steel, anodized aluminum, Teflon.RTM. and various
types of plastics, and functions to collect, condense and store
vaporized and aerosolized particles from breath exhaled
thereinto.
[0035] The exterior of collecting tube 60 may incorporate a
writable surface for subject users to identify samples with an
indelible marker or other suitable writing instrument.
Alternatively, a label with named fields for information could be
used or bar coding or other scannable data with identifying or
destination information could be imprinted on collecting tube 60
prior to delivery.
[0036] Duckbill valve 65 is inserted into the lower end of
collecting tube 60 a distance of approximately 1/2 inch and remains
in a closed position when the device is not in use. Duckbill valve
65 may be comprised of rubber or rubber-like elastomeric materials,
or plastics which approximate or behave as elastomers, and
functions to prevent the passage of air from the end 75 of
collecting tube 60 exposed to the atmosphere during the inhaling
process described below using mouthpiece 15 and to admit breath
from a subject user into collecting tube 60 during the exhaling
process, also described below. Its structure and function also
prevent the condensate collected in collecting tube 60 from
escaping during and after the breath condensate collection
procedure.
[0037] Cooling sleeve 70 is a hollow tube sized to slide over
collecting tube 60 and place the inner walls of cooling sleeve 70
into physical contact or at least close physical proximity with
collecting tube 60 shortly prior to and during practice of the
method of this invention. Cooling sleeve 70 may be slightly shorter
than collecting tube 60 and, when in place, should not extend to a
greater height than collecting tube 60. Cooling sleeve 70 may be
constructed of a material such as aluminum or any high specific
heat, durable, reusable material which does not deteriorate when
wet and tends to retain and maintain a low temperature when cooled.
In one preferred embodiment, the cooling sleeve might be a
container in which chemicals can be mixed that create an
endothermic reaction, thus providing substantial cooling.
[0038] When placed in position surrounding collecting tube 60 as
required for practice of the method of this invention, cooling
sleeve 70 functions to draw heat from the inner surface of
collecting tube 60, as will be described below, so as to accelerate
the condensing process occurring within the tube. In the preferred
embodiment, when properly positioned, collecting tube 60 extends on
one open end somewhat beyond the corresponding end of cooling
sleeve 70 and terminates approximately coequally with the end of
cooling sleeve 70 on the other end. Alternatively, collecting tube
60 may extend on the other end beyond the corresponding end of
cooling sleeve 70 so as to be insertable into opening 50 of
optional filter housing 40.
[0039] FIG. 2 provides a center cross-sectional view along a center
vertical axis of device 10 of all of the principal components of
device 10 in a disassembled state from the component positioned
vertically the lowest, mouthpiece 15, to that positioned highest,
airtight cap 80. Airtight cap 80 is provided as part of device 10
for secure, retentive placement over open end 75 of collecting tube
60 after the method of the invention has been practiced but prior
to storage and/or shipment of collecting tube 60 to a laboratory
for analysis of condensate. Together with normally closed duckbill
valve 65, airtight cap 80 seals the condensate sample within
collecting tube 60 and prevents any fluid exchange with matter or
air outside of collecting tube 60. Airtight cap 80 may be formed
from malleable plastic or another material, but its composition is
not critical to practice of the invention so long as it provides a
secure seal with open end 75 when placed thereover. Collecting tube
60, duckbill valve 65 and airtight cap 80 together form a
disposable assembly which may be prepackaged for a single use
ensuring no complicated cleaning or contamination issues arise from
use of device 10.
[0040] Duckbill valve 65 is a critical component of device 10. It
is uniformly constructed from rubber or a material with resilient,
rubber-like properties. FIG. 3 represents a cross-sectional view of
duckbill valve 65 taken below valve leaves 100, shown in FIGS. 4
and 5 below, prior to its insertion into collecting tube 60 along a
plane perpendicular to the walls of collecting tube 60 were
duckbill valve 65 inserted therein. Note that since collecting tube
60 has a circular cross-section, as indicated by dotted line 85,
one would normally expect duckbill valve 65 to have a
correspondingly circular cross-section. However, its cross-section
is uniquely elliptical so that, when forced into a circular shape,
such as in the circular bore of collecting tube 60, it will deform
disproportionately so as to create a complete seal between the
valve leaves 100 of duckbill valve 65, shown in FIGS. 4 and 5
below. This structure provides a seal even at zero reverse
differential pressure and is dissimilar from duckbill valves known
in the art that require pressure gradients to assure complete valve
closure. This feature is particularly valuable in this invention
since it assists in providing a secure and long-lasting seal to
keep condensate inside collecting tube 60 during long-term storage
and/or transport.
[0041] FIG. 4 additionally shows a center cross-sectional view of
duckbill valve 65 across the center of both leaves 100 of the valve
on a plane parallel to the walls of collecting tube 60 along line
A-A of FIG. 3. Leaves 100 incorporate malleable structures 105 with
which they are attached to section 115 of the body of duckbill
valve 65. An opening may be formed along the slit where leaves 100
meet each other. The center of duckbill valve 65 is hollow. Due to
the elliptical valve shape constrained in a circular structure,
leaves 100 are biased to a closed position along malleable
structures 105. Thus, when a subject user is inhaling, leaves 100
prevent the admission of air into mouthpiece 15 through collecting
tube 60. However, during exhaling, leaves 100 open along the slit
where they meet and admit air into collecting tube 60. The
structure of duckbill valve 65 also results in the creation of
turbulence during exhalation which helps to improve condensation
efficiency along the walls of collecting tube 60. For example,
shallow breathing through an empty collecting tube 60 is not very
turbulent. But when shallow breathing is directed through duckbill
valve 65, leaves 100 open only a little , and leaves 100 vibrate,
proving that there is turbulent airflow. When heavier breathing at
a higher velocity occurs, leaves 100 open further, preventing
increased resistance from occurring while still encouraging
turbulence.
[0042] During exhalation, particles of airway lining fluid are
ripped off the airway wall and carried in the humid airstream out
of the body. When the ambient temperature declines below the dew
point (i.e. upon egress from the mouth), the gas phase water
vapor/water molecules attach themselves onto the small aerosolized
particles, enlarging the particles and increasing the chance by
inertia that they will strike nearby surfaces such as the interior
walls of collecting tube 60, especially where there is turbulent
airflow. Thus, the creation of turbulent airflow by duckbill valve
65 is another important feature since it allows fluid particles to
impact the inner surface of collecting tube 60, encouraging fluid
collection.
[0043] Duckbill valve 65 incorporates a notched area around its
exterior into which is tightly and sealingly fitted a rubberized
Teflon.RTM. ring 110 having an exterior diameter just slightly
greater than that of the minor axis of the ellipse formed by the
footprint of duckbill valve 65 when at rest. Therefore, when ring
110 is in place, it is biased and makes sealing contact with the
interior walls of collecting tube 60. Ring 110 may also be composed
of materials other than Teflon.RTM. such as polypropylene, so long
as it functions in the same way as does the Teflon.RTM. ring
described. This ring serves three functions. First, it is a wiper
which, as discussed below, removes condensation from the interior
walls of collecting tube 60 after the subject user has completed
exhalation. Second, it maintains the alignment of duckbill valve 65
in an orthogonal orientation to the walls of collecting tube 60.
Finally, it functions as a valve itself as discussed next.
[0044] The lower part of duckbill valve 65 consists of two general
sections 115 and 120. There are one or more hollow passageways 125
running diagonally upward from an initiation point 130 within the
interior hollow area of duckbill valve 65 through lower section 120
into the circular notched area formed on the exterior of duckbill
valve 65. Note that only one passageway 125 is required for
subsequent degassification or deaeration steps, although as many as
ten such passageways may be preferred depending on the
circumstances. Also, note that such passages are not
circumferential around the valve, so that in a slightly different
cross section, they would not be seen at all, revealing that upper
section 115 is confluent with lower section 120 throughout most of
the valve structure.
[0045] Lower section 120 tends to be stiffer than upper section 115
since there is a greater volume of material in lower section 120
and, unlike section 115, it is constrained from movement by direct
contact with the walls of collecting tube 60. Thus, when gas
pressure is introduced through passageways 125 against Teflon.RTM.
ring 110, section 115 has a tendency to deflect allowing the gas to
pass around Teflon.RTM. ring 110 and into the portion of collecting
tube 60 above duckbill valve 65. First inner ring 135 is a
bump-like ridge extending around the hollow inner portion of
duckbill valve 65 at approximately at its base. Second inner ring
140 is another bump-like ridge extending around the hollow inner
portion of duckbill valve 65 at a point displaced slightly above
initiation point 130 of any passageway 125. The importance of these
features will become clear in conjunction with discussion of the
degassing of collecting tube 60 discussed below in conjunction with
FIGS. 6 and 7.
[0046] FIG. 5 shows a side view of duckbill valve 65 along a plane
rotated 90 degrees around a vertical axis from the view shown in
FIG. 4. This represents a side view along the plane represented by
the line B-B of FIG. 3. As is evident, the valve has a bilateral
structural symmetry.
[0047] The method of this invention is practiced after device 10
has been assembled as described above and shown in the drawings.
Although not a required assembly step, cooling sleeve 70 may be
placed in a freezer for approximately 20 to 30 minutes prior to use
since the larger the difference in temperature between the walls of
cooling sleeve 70 and collecting tube 60 the faster and more
efficiently condensation will occur and the greater the amount of
condensate produced will be. It is required, however, that cooling
sleeve 70 be somewhat cooler than collecting tube 60 prior to
beginning to practice the method so that the condensation process
will be enhanced. The cooling sleeve 70 can be cooled to various
temperatures depending on need. When chilled to -20 degrees C. or
below, for example, the exhaled fluid and vapors collect as frozen
solid material on the inside of the collecting tube 60, a feature
advantageous for the assays of compounds unstable in liquid phase
water, as would be the case with a cooling sleeve chilled to a
somewhat higher temperature. Temperatures obtained in a home
refrigerator or home freezer are satisfactory for excellent liquid
phase fluid collection for most purposes, including assessing pH.
Throughout practice of the method until after installation of
airtight cap 80, it is preferable to keep collecting tube 60
reasonably perpendicular to the ground.
[0048] As the first step in the method, referring again for visual
reference to FIG. 1, a subject user places projection 20 of mouth
piece 15 between his or her lips and inhales. Duckbill valve 65
remains closed due to the bias of flaps 100 and air is admitted
into mouthpiece 15 from projection 25 through check valve 30. The
subject user then exhales. The stream of exhaled breath is blocked
from egress out of projection 25 by check valve 30 and follows the
path of least resistance upward through projection 35 into optional
filter housing 40, through optional filter assembly 55 and into
duckbill valve 65 where leaves 100 are caused to separate and open
due to the air pressure allowing the exhaled breath to enter
collecting tube 60. When exhalation is complete, leaves 100 return
to their naturally biased closed position.
[0049] Due to the temperature differential between the exhaled
breath and the air inside and the walls of collecting tube 60, the
temperature of which has been lowered due to the contact or close
proximity of collecting tube 60 with cooling sleeve 70,
condensation begins to form on the walls of collecting tube 60 as
exhaled breath traverses the length of collecting tube 60. Due to
the force of gravity, some condensate tends to run down the walls
of collecting tube 60 to form a pool around Teflon.RTM. ring 110 at
the base of duckbill valve 65. Most remains in place as tiny
droplets on the inner wall of collecting tube 60. Meanwhile, the
remaining, now dehydrated, exhaled breath is allowed to escape from
open end 75 of collecting tube 60 which remains open to the
atmosphere. In general, between about two and twenty minutes of
breathing will be performed to provide sufficient sample. In
preferred embodiments, a set number of breaths, for example ten,
will be sufficient.
[0050] While keeping collecting tube 60 perpendicular to the ground
and the end of collecting tube 60 containing duckbill valve 65
nearest to the ground, cooling sleeve 70 is slid away from
collecting tube 60. Then, while keeping collecting tube 60
reasonably perpendicular to the ground and the end of collecting
tube 60 containing duckbill valve 65 nearest to the ground,
optional filter housing 40 and collecting tube 60 are manually
pulled apart and disengaged from each other. Alternatively,
projection 35 and collecting tube 60 are manually pulled apart, if
the filter is not employed.
[0051] A piston and rod combination is provided as an accessory to
device 10. The piston is designed to fit within collecting tube 60
and to be placed into uniform flat contact with the entire bottom
surface of duckbill valve 65 after cooling sleeve 70 and collecting
tube 60 are separated. The rod may be attached to the piston in
advance or after insertion of the piston into collecting tube 60.
Pressure is then exerted against duckbill valve 65 by means of the
rod and piston combination moving duckbill valve 65 vertically
upwards through the inside of collecting tube 60 towards open end
75 thereof. Due to the wiper action of Teflon.RTM. ring 110, tiny
drops of condensate clinging to the walls of collecting tube 60 are
collected into a small pool building up around and ahead of
Teflon.RTM. ring 110. The rod and piston combination are removed
from collecting tube 60 when duckbill valve 65 has been moved to
within approximately two inches from open end 75 of collecting tube
60. At this point, airtight cap 80 is securely and sealably
installed over open end 75 so that collecting tube 60 may be stored
and/or shipped to another location, such as a laboratory. By moving
duckbill valve 65 towards open end 75, the volume of air within
collecting tube 60 is reduced for storage purposes, and the surface
area of the condensate which might come into contact with
contaminating air is minimized. Alternatively, the movement of
duckbill valve 65 within collecting tube 60 can be deferred until
after transport. When desired, this piston and rod combination may
also serve the additional purpose of providing a degassing
mechanism, as discussed below.
[0052] Once sealed collecting tube 60 has arrived at a testing
location, which may even be at a subject user's home or workplace
if diagnostic equipment is stationed there, the collected
condensate may be subjected to a variety of treatments depending on
the assay desired to be undertaken. Where acidity of the condensate
is to be tested or of concern, a degassing or deaeration of the
condensate is performed. Degassing or deaerification is a
purification process which removes carbon dioxide from the
condensate and allows for more accurate and stable measurement of
acidity or pH levels. Without this deaeration step, the carbon
dioxide in air diffuses in and out of the condensate, changing its
pH. This can occur simply as the result of a person breathing over
the top of collecting tube 60 when it is open. Thus, any gas that
does not contain carbon dioxide or another acid may be used for
degassing prior to pH measurement including, but not limited to,
argon, helium, oxygen or air that has had carbon dioxide removed
from it with a carbon dioxide trap. Alternatively, elimination of
carbon dioxide could be accomplished chemically by adding an enzyme
and substrate that consumes carbon dioxide and a proton (acid) in a
one-to-one ratio.
[0053] In order to perform degassing on the condensate in sealed
collecting tube 60, any one of three methods may be used. First, a
probe, which may also serve as the piston discussed previously, may
be inserted through the bottom open end of collecting tube 60 and
advanced until its further progress is blocked by contact with
duckbill valve 65 whereupon pressure is exerted until the nose
portion of the probe is seated within duckbill valve 65. Airtight
cap 80 should then be removed. Reference is now made to FIG. 6
where a partial cross-sectional view of collecting tube 60 is shown
in which probe 200 has been seated within duckbill valve 65. The
nose portion of probe 200 has a diameter slightly wider than the
diameter of first inner ring 135. In order to seat probe 200, the
nose portion is pushed into the hollow center of duckbill valve 65
until further forward movement is impeded by contact between the
wider shoulder portion of probe 200 and lower section 120 of
duckbill valve 65. At this point, first inner ring 135 has been
compacted horizontally so as to form a pressure seal around the
nose portion of probe 200 below passageway 125, while second inner
ring 140 has also been compacted horizontally to form another
pressure seal around the nose portion of probe 200 above passageway
125.
[0054] Probe 200 includes a hollow, multipath, cylindrical
passageway 205 including one or more openings 210 which exit the
nose portion of probe 200 at a height equivalent to the location of
initiation point 130 within valve 65. Specifically, the location of
openings 210 lies between first inner ring 135 and second inner
ring 140 inside valve 65. Argon or another carbon dioxide-free gas
may be introduced under pressure through passageways 205 of probe
200. As shown in FIG. 7, the pressurized gas follows the path
indicated by the dotted lines accompanied by arrows. The mechanical
pressure seals formed by inner rings 135 and 140 against the nose
portion of probe 200 are considerably stronger than the seal
produced by ring 110 against the circular notched area formed on
the exterior of duckbill valve 65. Due to the positioning of
passageway(s) 125, they are not subjected to stress and exit
duckbill valve 65 at a point where the valve is not subjected to
mechanical stress. As a result, the pressurized gas introduced
through passageways 205 follows the unstressed portion of duckbill
valve 65, or passageways 125.
[0055] As explained above, upper section 115 tends to deflect when
exposed to pressurized gas thereby creating a passageway for the
gas to circumvent Teflon.RTM. ring 110 and escape into and bubble
through condensate 215 pooled in collecting tube 60. Carbon dioxide
dissolved in condensate diffuses into the bubbles of the carbon
dioxide-free gas. After having passed through condensate 215, the
gas, now containing carbon dioxide derived from the condensate is
allowed to escape into the atmosphere from collecting tube 60
through now uncapped open end 75. Argon, being heavier than air,
assists in preventing carbon dioxide from the ambient air from
recontaminating the sample.
[0056] An alternative structure for duckbill valve 65 could omit
ring 110 and hollow passageways 125 and probe 200. In this case,
gas pressure applied into collecting tube 60 below valve 65 by a
positive pressure manifold would cause leaves 100 in duckbill valve
65 to open admitting the gas into the condensate pool. The pressure
of the gas would prevent condensate from seeping back into the open
valve as would the closing bias of leaves 100 when the application
of gas pressure terminated. One example of such a manifold would
accept the lower end of collecting tube 60, make an airtight seal
with it and hold it in a vertical position while forcing gas into
the tube for degassing. The manifold could interface with available
gas plumbing or hoses connecting to a source of gas.
[0057] The third method for degassing is shown in schematic form in
FIG. 8. Pursuant to that method, airtight cap 80 is removed from
collecting tube 60 which is then inserted into a device enclosing
both ends of the tube. A hard vacuum is applied to both ends of the
tube and the area of the tube below the duckbill valve is
periodically opened to the atmosphere or to a carbon dioxide-free
gas source. This procedure draws the carbon dioxide out of the
solution in the condensate and allows it to be removed through the
vacuum pump. Open end 75 of collecting tube 60 is placed in
manifold 300, while the opposing end of the tube is placed in
manifold 305. Vacuum pump 310 is attached to open end 75 by means
of manifold 300, while vacuum gauge 315 is attached to the opposing
end of collecting tube 60 by means of manifold 305. Three-way,
two-position solenoid valve 320 is connected between vacuum pump
310 and vacuum gauge 315. An adjustable orifice 325 functioning
with solenoid valve 320 is used to regulate the surge of air or
other gas into the lower chamber of collecting tube 60, and a
filter 330 is connected to adjustable orifice 325 in order to
ensure that no contaminants are introduced into the system. A human
may be used to determine when to vent the lower part of collecting
tube 60 through manifold 305 based on readings from vacuum gauge
315. Alternatively, a vacuum transducer coupled to a controller
could be substituted for the vacuum gauge to automate the venting
of the collecting tube by energizing solenoid valve 320 pursuant to
a control algorithm.
[0058] Certain tests might require passing other gases through or
adding liquids or solids to the condensate. The same structures and
procedures described above may be used to collect, transport, store
and otherwise accomplish these tasks. Other tests that might be
performed on collected samples include assays for inorganic and
organic compounds, including but not limited to amino acids,
volatile organic compounds, lipids and lipid oxidation products,
armmonia, simple ions such as sodium and chloride, strong and weak
acids and bases, surfactant, inflammatory mediators including
cytokines and leukotrienes, oxidation and nitration products
including hydrogen peroxide and nitrotyrosine, nucleic acids such
as DNA and RNA, endotoxin and other microbial products. In
addition, it is important to note that the entire cycle of
sampling, storage, degassing and much, if not all, of the analysis
is done within device 10. Transfer of fluid to other apparati is
not generally required. Furthermore, all wetted parts of device 10
can easily be made disposable to minimize contamination, cleaning,
and cost. The device is fully portable and can be used even by
small children. In an alternative structure, a filter may be
positioned on top of collecting tube 60 to prevent infectious
particles from escaping while allowing larger particles to be
trapped in collecting tube 60. Finally, the device and method of
this invention may be adapted for animal use in veterinarian
applications.
[0059] When the collected condensate sample has been prepared for
testing as required, either by degassing or by addition of gas,
liquid or another substance, a probe may be inserted through open
end 75 to remove a sample of the condensate for testing purposes.
Alternatively, the testing can be performed directly within
collecting tube 60. For example, after degassing, a calibrated pH
probe attached to a pH meter can be immersed in the collected
sample to determine sample pH. The sample may be removed by contact
with the probe or by suction action through the probe. In other
embodiments, chemicals can be added, or a chemically impregnated
reagent strip can be immersed into the sample for colorimetric
determination of pH and other characteristics and substances.
[0060] The foregoing invention has been described in terms of the
preferred embodiment. However, it will be apparent to those skilled
in the art that various modifications and variations can be made to
the disclosed method and system without departing from the scope or
spirit of the invention. The specification and examples are
exemplary only, while the true scope of the invention is defined by
the following claims.
* * * * *