Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR COLLECTING A BREATH SAMPLE USING AN AIR
CIRCULATION SYSTEM
FIELD
[0001] The specification relates generally to sample collection
systems, and more
particularly to apparatuses and methods for collecting a breath sample.
BACKGROUND OF THE DISCLOSURE
[0002] Breath sample collection has traditionally been performed by
collecting breath
from a patient in a large container. The breath sample is then extracted from
the container
and transferred directly to an analyzer.
[0003] More recently, breath samples have been collected in breath
sample storage
devices known as sorbent tubes or thermal desorption tubes. Sorbent tubes are
tubes
containing a solid adsorbent material having a large surface area. When a
gaseous sample
is passed through a sorbent tube, some of the constituents, such as oxygen and
carbon
dioxide, flow through and out the other end of the sorbent tube, whereas other
constituents
are adsorbed by the adsorbent material. This enables many of the constituents
of a breath
sample to be captured by the adsorbent material while allowing the most
voluminous
constituents to flow through, thereby condensing the breath sample. As a
result, most of the
constituents of the breath sample can be collected within a much smaller
volume.
[0004] Devices that allow these sorbent tubes to be filled directly
by a person suffer from
a number of issues, however. Within human breath is a significant amount of
humidity that
can interfere with this mode of breath collection. The humidity can form
condensation on the
inside of the conduits directing the breath to the sorbent tubes. This
condensation attracts
many of the constituents of breath, which freely adhere to the water
molecules. As a result,
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many of the breath sample constituents do not make it to the sorbent tube and
are thus not
represented in the at least some of the breath sample that is analyzed.
[0005] Another issue is that sorbent tubes capture the constituents
of breath more
effectively at certain flow rates of breath through the sorbent tubes. The
rate at which breath
is flowed through the sorbent tubes in state-of-the-art devices is driven by
the rate at which
breath is blown into these devices by the person. This leads to a loss of
parts of the breath
sample.
SUMMARY OF THE DISCLOSURE
[0006] In one aspect, there is provided an apparatus for collecting
a breath sample,
comprising: a breath input interface configured to receive exhaled breath; a
container
connected to the breath input interface for storing at least some of the
breath; and at least
one controller configured to control a flow of the at least some of the breath
from the
container to at least one sorbent tube connected to the container asynchronous
of when the
breath is received.
[0007] The container can have a cavity in which the at least some of
the breath is stored,
a volume of the cavity being controllable. The volume of the cavity can be
controllable by
the at least one controller. The container can include a piston chamber that
has a piston
positioned therein, a position of the piston controlling the volume of the
cavity. The at least
one controller can be configured to actuate the piston to increase the volume
of the cavity
as the at least some of the exhaled breath is being received.
[0008] The apparatus can further include: a valve intermediate the
breath input interface
and the container; a first conduit system connecting the breath input
interface and the valve;
and a second conduit system connecting the container to the at least one
sorbent tube. The
at least one controller can be configured to control the valve to close and
control actuation
of the piston to impel the at least some of the breath through a subset of the
at least one
sorbent tube. A tube inlet valve can be positioned between the container and
each of the at
least one sorbent tube. The at least one controller can be configured to
control each of the
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at least one tube inlet valve to select the subset of the at least one sorbent
tube through
which the at least some of the breath is flowed.
[0009] The subset can be a first subset, the apparatus can further
include an inlet valve
positioned along the second conduit system between an inlet and the container,
the at least
one controller can be configured to open the inlet valve and control actuation
of the piston
to draw air through the inlet and into the cavity, and the at least one
controller can be
configured to close the inlet valve and impel the intaken air from the cavity
through the
second conduit system. The at least one controller can control actuation of
the piston to
impel the intaken air through a second subset of the at least one sorbent
tube. A tube inlet
valve can be positioned between the container and each of the at least one
sorbent tube.
The at least one controller can be configured to control each of the at least
one tube inlet
valve to select the second subset of the at least one sorbent tube through
which the intaken
air is flowed through.
[0010] The container can include an at least partially flexible
collapsible receptacle. The
apparatus can further comprise: a valve intermediate the breath input
interface and the
container; a first conduit system connecting the breath input interface and
the valve; and a
second conduit system connecting the container to the at least one sorbent
tube. The
apparatus can further include a pump controlled by the at least one controller
to impel the
at least some of the breath from the container through a subset of the at
least one sorbent
tube. A tube inlet valve can be positioned between the container and each of
the at least
one sorbent tube. The at least one controller can be configured to control
each of the at least
one tube inlet valve to select the subset of the at least one sorbent tube
through which the
at least some of the breath is flowed.
[0011] The pump can be positioned between the valve and the
container, and the at
least one controller can be configured to control the pump to draw the at
least some of the
exhaled breath into the container.
[0012] The subset can be a first subset, the apparatus can further
include an inlet valve
positioned along the second conduit system between an inlet and the container,
and the at
least one controller can be configured to close the inlet valve and control
the pump to flow
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air from the container through a second subset of the at least one sorbent
tube. The at least
one controller can be configured to open the inlet valve and control the pump
to flow air
through the inlet and into the cavity. A tube inlet valve can be positioned
between the
container and each of the at least one sorbent tube. The at least one
controller can be
configured to control each of the at least one tube inlet valve to select the
first subset of the
at least one sorbent tube through which the at least some of the breath is
flowed.
[0013] The apparatus can further comprise: a valve intermediate the
breath input
interface and the container; and a first conduit system connecting the breath
input interface
and the valve. The at least one controller can be configured to control the
valve to close and
control the volume of the container to impel the at least some of the breath
through a subset
of the at least one sorbent tube upon capturing a target volume of the breath
in the container.
The at least one controller can be configured to control the volume of the
container to
decrease at one of at least two breath flow rates at which the at least one
controller can
control the volume of the container to impel the breath through the subset of
the at least one
sorbent tube.
[0014] In another aspect, there is provided a method of collecting a
breath sample,
comprising: receiving exhaled breath via a breath input interface; storing at
least some of
the breath in a container connected to the breath input interface; and
controlling, via at least
one controller, a flow of the at least some of the breath from the container
to at least one
sorbent tube connected to the container asynchronous of when the exhaled
breath is
received.
[0015] The storing can comprise storing the at least some of the
exhaled breath in a
cavity of the container, and a volume of the cavity can be controllable. The
method can
further include controlling the volume of the cavity via the at least one
controller. The method
can further include actuating, via the at least one controller, a piston
positioned in a piston
chamber of the container, a position of the piston controlling the volume of
the cavity. The
method can further comprise actuating the piston to increase the volume of the
cavity as the
at least some of the exhaled breath is being received. The method can further
include
controlling a flow of the at least some of the exhaled breath via a valve
intermediate the
breath input interface and the container, wherein a first conduit system
connects the breath
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input interface and the valve, and wherein a second conduit system connects
the container
to the at least one sorbent tube. The method can further include: controlling
the valve via
the at least one controller to close; and controlling actuation of the piston
to impel the at least
some of the breath through a subset of the at least one sorbent tube. A tube
inlet valve can
be positioned between the container and each of the at least one sorbent tube,
and the
method can further include controlling each of the at least one tube inlet
valve to select the
subset of the at least one sorbent tube through which the at least some of the
breath is
flowed.
[0016] The method can further include: controlling, via the at least
one controller, the
valve to close; controlling an inlet valve separating the container from an
inlet to open;
controlling actuation of the piston to draw air through the inlet and into the
cavity; controlling
the inlet valve to close; and controlling actuation of the piston to impel the
intaken air from
the cavity through the second conduit system.
[0017] The method can further include controlling actuation of the
piston to impel the
intaken air through a second subset of the at least one sorbent tube. A tube
inlet valve can
be positioned between the container and each of the at least one sorbent tube.
The method
can further include controlling each of the at least one tube inlet valve to
select the second
subset of the at least one sorbent tube through which the intaken air is
flowed through.
[0018] The container can include an at least partially flexible
collapsible receptacle. The
method can further include controlling a flow of the at least some of the
breath via a valve
intermediate the breath input interface and the container, wherein a first
conduit system
connects the breath input interface and the valve, and wherein a second
conduit system
connects the container to the at least one sorbent tube. The method can
further include
controlling a pump to flow the at least some of the breath from the container
through a subset
of the least one sorbent tube. A tube inlet valve can be positioned between
the container
and each of the at least one sorbent tube. The method can further comprise
controlling each
of the at least one tube inlet valve to select the subset of the at least one
sorbent tube
through which the at least some of the breath is flowed.
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[0019] The pump can be positioned between the valve and the
container, and the
method can further include controlling the pump to draw the at least some of
the exhaled
breath into the container.
[0020] The subset can be a first subset, and the method can further
include: closing the
valve; opening an inlet valve intermediate an inlet and the container; and
controlling the
pump to flow air through a second subset of the at least one sorbent tube. The
method can
further include: opening the inlet valve; and controlling the pump to flow air
through the inlet
and into the cavity. A tube inlet valve can be positioned between the
container and each of
the at least one sorbent tube. The method can further include controlling each
of the at least
one tube inlet valve to select the subset of the at least one sorbent tube
through which the
at least some of the breath is flowed.
[0021] The method can further include controlling a flow of the
exhaled breath from a
first conduit system to which the breath input interface is connected through
to the container
via a valve. The method can further include: controlling the valve to close;
and controlling
the volume of the container to flow the at least some of the breath through a
subset of the
at least one sorbent tube upon capturing a target volume of the breath in the
container.
During the controlling the volume, the volume can be controlled to decrease at
one of at
least two breath flow rates at which the volume can be controlled to decrease
at to impel the
breath through the subset of the at least one sorbent tube.
[0022] In a further aspect, there is provided an apparatus for
collecting a breath sample,
comprising: a breath input interface configured to receive exhaled breath; a
metering device
configured to determine a constituent level in the breath being received; a
first conduit
system extending from the breath input interface and connected to at least one
breath
sample storage device; a valve positioned along the first conduit system to
control a flow of
the exhaled breath towards the at least one breath sample storage device; and
at least one
controller configured to determine if the constituent level is within a
constituent level target
range, determine if a change rate in the constituent level is within a
constituent level change
rate target range, and control the valve to open at least partially based on
whether the
constituent level is within the constituent level target range and the change
rate is within the
constituent level change rate target range.
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[0023] The metering device can be a capnometer, the constituent
level can be a carbon
dioxide level, the constituent level target range can be a carbon dioxide
level target range,
and the constituent level change rate target range can be a carbon dioxide
level change rate
target range. The apparatus can further include a flow meter configured to
determine a flow
rate of the exhaled breath being received, wherein the at least one controller
is configured
to control the valve to open at least partially based on the determined flow
rate being within
a flow rate target range. The apparatus can further include a display, wherein
the at least
one controller is configured to control the display to present flow rate
notifications thereon.
[0024] The apparatus can further include at least one light element,
wherein the at least
one controller is configured to control the at least one light element to
present flow rate
notifications therewith.
[0025] The apparatus can further include a speaker, wherein the at
least one controller
is configured to control the speaker to play audible flow rate notifications
therethrough.
[0026] The constituent level target range can extend between a
constituent level
minimum threshold and an infinite upper bound.
[0027] The constituent level change rate target range can extend
between an infinite
lower bound and a constituent level change rate maximum threshold.
[0028] The flow rate target range can extend between a minimum flow
rate threshold
and an infinite upper bound.
[0029] The at least one controller can be configured to monitor the
constituent level after
opening the valve.
[0030] The apparatus can further include a flow meter configured to
determine a flow
rate of the exhaled breath being received, wherein the at least one controller
is configured
to monitor the flow rate after opening the valve, and control the valve to
close at least partially
based on the determined flow rate being within a flow rate termination range.
[0031] In yet another aspect, there is provided a method for
collecting a breath sample,
comprising: receiving exhaled breath via a breath input interface from which a
first conduit
system extends towards at least one breath sample storage device, wherein a
valve is
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positioned to control travel of the exhaled breath from the first conduit
system towards the
at least one breath sample storage device; determining, via at least one
controller, if a
constituent level in the exhaled breath being received is within a constituent
level target
range; determining a change rate in the constituent level is within a
constituent level change
rate target range; and controlling the valve to open at least partially based
on whether the
constituent level is within the constituent level target range and the change
rate is within the
constituent level change rate target range.
[0032] The constituent level can be a carbon dioxide level, the
constituent level target
range can be a carbon dioxide level target range, and the constituent level
change rate
target range can be a carbon dioxide level change rate target range.
[0033] The method can further include determining a flow rate of the
exhaled breath
being received, wherein the capturing is performed at least partially based on
the determined
flow rate being within a flow rate target range. The method can further
include controlling a
display to present flow rate notifications thereon. The method can further
include controlling
at least one light element to present flow rate notifications therewith.
[0034] The method can further include control a speaker to play
audible flow rate
notifications therethrough.
[0035] The carbon dioxide level target range can extend between a
carbon dioxide level
minimum threshold and an infinite upper bound.
[0036] The carbon dioxide level change rate target range can extend
between an infinite
lower bound and a carbon dioxide level change rate maximum threshold.
[0037] The flow rate target range can extend between a minimum flow
rate threshold
and an infinite upper bound.
[0038] The method can further include monitoring the carbon dioxide
level after opening
the valve.
[0039] The method can further include determining a flow rate of the
exhaled breath
being received, wherein the at least one controller is configured to monitor
the flow rate after
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opening the valve, and control the valve to close at least partially based on
the determined
flow rate being within a flow rate termination range.
[0040] In still another aspect, there is provided an apparatus for
collecting a breath
sample, comprising: a breath input interface configured to receive exhaled
breath; a first
conduit system connected to the breath input interface; a valve configured to
control fluid
communication between the first conduit system and at least one breath sample
storage
device configured to store a breath sample; an air circulation system
configured to circulate
air through the first conduit system upon completion of a first received
exhaled breath; and
at least one controller configured to control the valve upon completion of the
first received
exhaled breath at least partially based on a humidity level in the first
conduit system.
[0041] The at least one controller can be configured to control the
valve at least partially
based on whether a change rate in the humidity level is within a humidity
level change rate
target range. The at least one controller can be configured to close the valve
to inhibit
passage of a subsequent exhaled breath from the first conduit system to the at
least one
breath sample storage device until the change rate in the humidity level
within the first
conduit system is within the humidity level change rate target range. The
apparatus can
further include a hygrometer connected to the first conduit system and
configured to
determine the humidity level in the first conduit system. The apparatus can
further include a
notification system for indicating when the change rate in the humidity level
within the first
conduit system is within the humidity level change rate target range.
[0042] The first conduit system can include a breath intake conduit
extending between
the breath input interface and the valve, and the hygrometer can be connected
to an exhaust
conduit of the first conduit system that branches from the breath intake
conduit. The fluid
circulation system can be directly connected to the exhaust conduit. The
exhaust conduit
can include a flow meter configured to measure a flow rate along the exhaust
conduit.
[0043] The at least one controller can be configured to control the
valve at least partially
based on whether the humidity level is within a humidity level target range.
The at least one
controller can be configured to close the valve to inhibit passage of a
subsequent exhaled
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breath from the first conduit system to the at least one breath sample storage
device until
the humidity level within the first conduit system is within the humidity
level target range.
[0044] In another aspect, there is provided a method for collecting
a breath sample,
comprising: receiving an exhaled breath via a breath input interface connected
to a first
conduit system; collecting at least some of the exhaled breath via at least
one breath sample
storage device connected to the first conduit system; detecting a completion
of the exhaled
breath; closing a valve between the first conduit system and the at least one
sorbent tube
upon detecting the completion of the exhaled breath; circulating air through a
first conduit
system connected to the breath input interface after detecting the completion
of the exhaled
breath; monitoring a humidity level in the first conduit system; and
controlling, via at least
one controller, the valve at least partially based on the humidity level in
the first conduit
system.
[0045] The controlling can include determining if a change rate in
the humidity level is
within a humidity level change rate target range. The method can further
include controlling
the valve to close to inhibit passage of a subsequently exhaled breath from
the first conduit
system to the at least one breath sample storage device until the change rate
in the humidity
level within the first conduit system is within the humidity level change rate
target range. The
method can further include determining the humidity level in the first conduit
system via a
hygrometer connected to the first conduit system. The method can further
include indicating
when the change rate in the humidity level is within the humidity level change
rate target
range.
[0046] The first conduit system can include a breath intake conduit
extending between
the breath input interface and the valve, and wherein the determining of the
humidity level
is performed by a hygrometer connected to an exhaust conduit of the first
conduit system
that branches from the breath intake conduit. The fluid circulation system can
be directly
connected to the exhaust conduit. The method can further include measuring a
flow rate
along the exhaust conduit via a flow meter along the exhaust conduit.
[0047] The controlling can include determining if the humidity level
is within a humidity
level target range. The method can further include controlling the valve to
close to inhibit
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passage of a subsequently exhaled breath from the first conduit system to the
at least one
breath sample storage device until the humidity level within the first conduit
system is within
the humidity level target range.
[0048] In a further aspect, there is provided an apparatus for
collecting a breath sample,
comprising: a breath input interface configured to receive exhaled breath; a
first conduit
system connected to the breath input interface; at least one breath sample
storage device
connected to the breath input interface via a breath intake conduit of the
first conduit system
extending between the breath input interface and the breath collection system,
the at least
one breath sample storage device being configured to capture at least some of
the breath;
and at least one metering device for measuring at least one characteristic,
the at least one
metering device being positioned along an exhaust conduit of the first conduit
system that
branches from the breath intake conduit.
[0049] The at least one metering device can include a flow meter
that measures a flow
rate of the exhaled breath along the exhaust conduit of the first conduit
system. The at least
one metering device can include a capnometer positioned along the exhaust
conduit of the
first conduit system to measure a carbon dioxide level in the exhaled breath.
[0050] The at least one metering device can include a hygrometer
positioned along the
exhaust conduit of the first conduit system to measure a humidity level in the
exhaled
conduit. The apparatus can further include a pump positioned along the exhaust
conduit of
the first conduit system to flow air through the exhaust conduit.
[0051] In yet another aspect, there is provided a method for
collecting a breath sample,
comprising: receiving exhaled breath via a breath input interface; a first
conduit system
connected to the breath input interface; capturing breath via a breath
collection system that
is connected to the breath input interface via a breath intake conduit of a
first conduit system
extending between the breath input interface and the breath collection system;
and
measuring at least one characteristic along an exhaust conduit of the first
conduit system
that branches from the breath intake conduit via at least one metering device
positioned
along the exhaust conduit.
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[0052] The at least one metering device can include a flow meter,
and the at least one
characteristic can include a flow rate of the exhaled breath along the exhaust
conduit.
[0053] The at least one metering device can include a capnometer,
and the at least one
characteristic can include a carbon dioxide level of the exhaled breath.
[0054] The method can further include determining a humidity level
along the exhaust
conduit via a hygrometer positioned along the exhaust conduit of the first
conduit system.
The method can further include flowing air through the exhaust conduit via a
pump
positioned along the exhaust conduit.
[0055] In still yet another aspect, there is provided an apparatus
for collecting a breath
sample, comprising: a breath input interface configured to receive exhaled
breath; a
container connected to the breath input interface for receiving at least some
of the exhaled
breath, the container having a cavity with a volume that is controllable; and
at least one
controller configured to control the volume of the cavity to increase at a
volume increase
rate that is at most equal to a flow rate of the exhaled breath received by
the breath input
interface.
[0056] A breath intake conduit of a first conduit system can extend
from the breath input
interface and towards the container, and an exhaust conduit of the first
conduit system can
branch from the breath collecting portion at a first end thereof and has an
outlet at a second
end thereof. The apparatus can further include a flow meter positioned to
measure a flow
rate along the exhaust conduit. The volume increase rate of the volume of the
container can
be proportional to the flow rate along the exhaust conduit. The volume of the
container can
be directly mechanically controllable by the at least one controller. The
container can include
a piston chamber having an actuatable piston positioned therein, a position of
the piston in
the piston chamber defining the volume of a cavity. The apparatus can further
include a
valve positioned to control travel of the exhaled breath to the piston
chamber. The apparatus
can further include at least one sorbent tube connected to the container,
wherein the at least
one controller is configured to control the valve to close and control
actuation of the piston
to impel the breath in the cavity through the at least one sorbent tube.
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[0057] The container can include an at least partially flexible
collapsible receptacle, and
the apparatus can further include a pump configured intermediate the breath
input interface
and the container to impel the breath into the at least partially flexible
collapsible receptacle
at the volume increase rate. The apparatus can further include at least one
sorbent tube
connected to the at least partially flexible collapsible receptacle, wherein
the at least one
controller is configured to control the pump to impel the breath in the cavity
through a subset
of the at least one sorbent tube. The apparatus can further include a valve
positioned to
control travel of the exhaled breath to the piston chamber.
[0058] The apparatus can further include a valve positioned to
control travel of the
exhaled breath to the piston chamber. The apparatus can further include a
metering device
positioned to determine a constituent level in the exhaust conduit, and the at
least one
controller can be configured to determine if the constituent level is within a
constituent level
target range, determine if a change rate in the constituent level is within a
constituent level
change rate target range, and control the valve to open at least partially
based on whether
the constituent level is within the constituent level target range and the
change rate is within
the constituent level change rate target range. The metering device can be a
capnometer,
the constituent level can be a carbon dioxide level, the constituent level
target range can be
a carbon dioxide level target range, and the constituent level change rate
target range can
be a carbon dioxide level change rate target range.
[0059] The apparatus can further include: a breath intake conduit of
a first conduit system
extending from the breath input interface and towards the container; and a
flow meter
positioned to measure a flow rate of the exhaled breath along the breath
intake conduit. The
volume increase rate of the volume of the container can be proportional to the
flow rate
along the breath intake conduit. The volume of the container can be directly
mechanically
controllable by the at least one controller. The container can include a
piston chamber
having an actuatable piston positioned therein, a position of the piston in
the piston chamber
defining the volume of a cavity. The apparatus can further include a valve
positioned to
control travel of the exhaled breath to the piston chamber. The apparatus can
further include
at least one sorbent tube connected to the container, wherein the at least one
controller is
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configured to control the valve to close and control actuation of the piston
to impel the breath
in the cavity through a subset of the at least one sorbent tube.
[0060] The container can include an at least partially flexible
collapsible receptacle, and
the apparatus can further include a pump configured intermediate the breath
input interface
and the container to impel the breath into the at least partially flexible
collapsible receptacle
at the volume increase rate.
[0061] In still yet another aspect, there is provided a method for
collecting a breath
sample, comprising: receiving exhaled breath via a breath input interface;
storing at least
some of the exhaled breath in a container connected to the breath input
interface, the
container having a cavity with a volume that is controllable; and controlling,
via at least one
controller, the volume of the container to increase at a volume increase rate
that is at most
equal to a flow rate of the exhaled breath received by the breath input
interface.
[0062] A breath intake conduit of a first conduit system can extend
from the breath input
interface and towards the container, and an exhaust conduit of the first
conduit system can
branch from the breath collecting portion at a first end thereof and has an
outlet at a second
end thereof. The method can further include measuring a flow rate along the
exhaust conduit
via a flow meter. The volume increase rate of the volume of the container can
be proportional
to the flow rate. The method can further include directly mechanically
controlling the volume
of the container. The container can include a piston chamber in which a piston
is positioned,
the position of the piston defining the volume of a cavity, and wherein the
directly
mechanically controlling comprises actuating the piston. The method can
further include
travel of the exhaled breath to the piston chamber via a valve positioned
between the breath
input interface and the container. The method can further include: controlling
the valve to
close; and controlling actuation of the piston to impel the breath in the
cavity through at least
one sorbent tube connected to the container.
[0063] The container can include an at least partially flexible
collapsible receptacle, and
the method can further include impelling, via a pump intermediate the breath
input interface
and the container, the exhaled breath into the at least partially flexible
collapsible receptacle
at the volume increase rate.
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[0064] The method can further include controlling the pump to impel
the breath in the
cavity through a subset of at least one sorbent tube connected to the at least
partially flexible
collapsible receptacle. The method can further include controlling travel of
the exhaled
breath to the piston chamber via a valve.
[0065] The method can further include controlling travel of the
exhaled breath to the
piston chamber via a valve. The method can further include: determining a
constituent level
in the exhaust conduit; comparing, via the at least one controller, the
constituent level to a
constituent level target range; comparing a change rate in the constituent
level to a
constituent level change rate target range; and control the valve to open at
least partially
based on whether the constituent level is within the constituent level target
range and
whether the change rate is within the constituent level change rate target
range. The
constituent level can be a carbon dioxide level, the constituent level target
range can be a
carbon dioxide level target range, and the constituent level change rate
target range can be
a carbon dioxide level change rate target range.
[0066] A breath intake conduit of a first conduit system can extend
from the breath input
interface and towards the container, and the method can further include
measuring a flow
rate of the exhaled breath along the breath intake conduit via a flow meter.
The volume
increase rate of the volume of the container can be proportional to the flow
rate. The method
can further include directly mechanically controlling the volume of the
container by the at
least one controller. The container can include a piston chamber having an
actuatable piston
positioned therein, and the method can further include actuating a position of
the piston in
the piston chamber defining the volume of a cavity. The method can further
include
controlling travel of the exhaled breath to the piston chamber via a valve.
The method can
further include: controlling the valve to close; and controlling actuation of
the piston to impel
the breath in the cavity through a subset of at least one sorbent tube
connected to the
container.
[0067] The container can include an at least partially flexible
collapsible receptacle, and
the method can further include impelling the breath into the at least
partially flexible
collapsible receptacle at the volume increase rate via a pump positioned
intermediate the
breath input interface and the container.
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[0068] Other technical advantages may become readily apparent to one
of ordinary skill
in the art after review of the following figures and description.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0069] For a better understanding of the embodiment(s) described
herein and to show
more clearly how the embodiment(s) may be carried into effect, reference will
now be made,
by way of example only, to the accompanying drawings in which:
[0070] FIG. 1 shows a breath sample collection apparatus in
accordance with one
embodiment thereof;
[0071] FIG. 2 shows a schematic diagram showing a sorbent tube for
use with the
apparatus of FIG. 1;
[0072] FIG. 3 is a flowchart of the general method of collecting
breath using the
apparatus of FIG. 1;
[0073] FIG. 4A shows the breath sample collection apparatus of FIG.
1, wherein ambient
air is being drawn in to a piston chamber;
[0074] FIG. 4B shows the breath sample collection apparatus of FIG.
4A during flushing
of the apparatus with the ambient air;
[0075] FIG. 4C shows sorbent tubes fitted in the breath sample
collection apparatus of
FIG. 4A and ambient air being drawn into the container;
[0076] FIG. 4D shows the ambient air being impelled through one of
the sorbent tubes
in the breath sample collection apparatus of FIG. 4A;
[0077] FIG. 4E shows the breath sample collection apparatus of FIG.
4A as a person
commences to breathe into the breath sample collection apparatus;
[0078] FIG. 4F shows the breath sample collection apparatus of FIG.
4C collecting a
breath sample after the breath is determined to be alveolar;
[0079] FIG. 4G shows the breath sample collection apparatus of FIG.
4C being used to
prime the breath sample collection apparatus;
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[0080] FIG. 4H shows the breath sample collection apparatus of FIG.
4C collecting a
breath sample after sorbent tubes have been loaded;
[0081] FIG. 41 shows the breath sample collection apparatus of FIG.
4C flowing the
collected breath sample through one of the sorbent tubes;
[0082] FIG. 5 shows a graph of the carbon dioxide level in breath
over time during a
breath;
[0083] FIG. 6 shows the humidity level in the breath sample
collection apparatus while
the humidity is being removed by the pump;
[0084] FIG. 7A shows an apparatus for collecting a breath sample
including a collapsed
bag and its operating environment in accordance with another embodiment;
[0085] FIG. 7B shows the apparatus of FIG. 7A, wherein the bag is
expanded; and
[0086] FIG. 8 shows a breath sample collection apparatus in
accordance with a further
embodiment.
[0087] Unless otherwise specifically noted, articles depicted in the
drawings are not
necessarily drawn to scale.
DETAILED DESCRIPTION
[0088] For simplicity and clarity of illustration, where considered
appropriate, reference
numerals may be repeated among the Figures to indicate corresponding or
analogous
elements. In addition, numerous specific details are set forth in order to
provide a thorough
understanding of the embodiment or embodiments described herein. However, it
will be
understood by those of ordinary skill in the art that the embodiments
described herein may
be practiced without these specific details. In other instances, well-known
methods,
procedures and components have not been described in detail so as not to
obscure the
embodiments described herein. It should be understood at the outset that,
although
exemplary embodiments are illustrated in the figures and described below, the
principles of
the present disclosure may be implemented using any number of techniques,
whether
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currently known or not. The present disclosure should in no way be limited to
the exemplary
implementations and techniques illustrated in the drawings and described
below.
[0089] Various terms used throughout the present description may be
read and
understood as follows, unless the context indicates otherwise: "or" as used
throughout is
inclusive, as though written "and/or"; singular articles and pronouns as used
throughout
include their plural forms, and vice versa; similarly, gendered pronouns
include their
counterpart pronouns so that pronouns should not be understood as limiting
anything
described herein to use, implementation, performance, etc. by a single gender;
"exemplary"
should be understood as "illustrative" or "exemplifying" and not necessarily
as "preferred"
over other embodiments. Further definitions for terms may be set out herein;
these may
apply to prior and subsequent instances of those terms, as will be understood
from a reading
of the present description.
[0090] Modifications, additions, or omissions may be made to the
systems, apparatuses,
and methods described herein without departing from the scope of the
disclosure. For
example, the components of the systems and apparatuses may be integrated or
separated.
Moreover, the operations of the systems and apparatuses disclosed herein may
be
performed by more, fewer, or other components and the methods described may
include
more, fewer, or other steps. Additionally, steps may be performed in any
suitable order. As
used in this document, "each" refers to each member of a set or each member of
a subset
of a set.
[0091] Any module, unit, component, server, computer, terminal,
engine or device
exemplified herein that executes instructions may include or otherwise have
access to
computer readable media such as storage media, computer storage media, or data
storage
devices (removable and/or non-removable) such as, for example, magnetic disks,
optical
disks, or tape. Computer storage media may include volatile and non-volatile,
removable
and non-removable media implemented in any method or technology for storage of
information, such as computer readable instructions, data structures, program
modules, or
other data. Examples of computer storage media include RAM, ROM, EEPROM, flash
memory or other memory technology, CD-ROM, digital versatile disks (DVD) or
other optical
storage, magnetic cassettes, magnetic tape, magnetic disk storage or other
magnetic
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storage devices, or any other medium which can be used to store the desired
information
and which can be accessed by an application, module, or both. Any such
computer storage
media may be part of the device or accessible or connectable thereto. Further,
unless the
context clearly indicates otherwise, any processor or controller set out
herein may be
implemented as a singular processor or as a plurality of processors. The
plurality of
processors may be arrayed or distributed, and any processing function referred
to herein
may be carried out by one or by a plurality of processors, even though a
single processor
may be exemplified. Any method, application or module herein described may be
implemented using computer readable/executable instructions that may be stored
or
otherwise held by such computer readable media and executed by the one or more
processors.
[0092] A breath sample collection apparatus 20 in accordance with an
embodiment is
shown in FIG. 1. The breath sample collection apparatus 20 enables a breath
sample to be
collected in sorbent tubes asynchronously of when exhaled breath is provided.
The breath
sample collection apparatus 20 includes a container for receiving exhaled
breath. The
breath is subsequently flowed through one or more sorbent tubes asynchronously
of when
the breath is received. The flowing of the breath through the one or more
sorbent tubes can
be performed by generating a positive relative pressure difference to impel
the breath, by
generating a negative relative pressure difference to draw the breath, or in
any other suitable
manner. As a result, the adsorption of the breath by the sorbent tubes can be
controlled
more stringently.
[0093] The breath sample collection apparatus 20 includes a breath
input interface 24
for receiving exhaled breath from a person. The breath input interface 24
includes a
mouthpiece 36 that is secured to a breath intake end 40 of a breath intake
conduit 44 of a
pre-collection conduit system 46.
[0094] The mouthpiece 36 is made of polypropylene or another
suitably safe material
that is preferably inexpensive so that it can be disposable/replaced. Further,
preferably, the
mouthpiece 36 does not off-gas volatile organic compounds ("VOCs") or off-
gases VOCs at
a low rate so that it does not significantly contaminate the breath sample. It
can include a
viral/bacterial filter to keep bacterium and particulates out of the sample.
By making the
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mouthpiece 36 disposable, each patient can be provide with a new filter to
avoid cross-
contamination of the samples and passing on of viruses, bacteria, etc.
[0095] The polypropylene of the mouthpiece 36 is clear and will
slightly fog up if humidity
is high. This feature can be used to visibly detect condensation, as it can be
undesirable to
have condensation in the breath sample collection apparatus 20.
[0096] In other embodiments, the breath input interface can be
constructed to receive
breath from other animals.
[0097] The conduits of the breath sample collection apparatus 20 are
made of stainless
steel that is coated with an inert coating. The inert coating can be made of
any suitably inert
substance, such as a silica-based or quartz material.
[0098] An exhaust conduit 48 is connected to and branches from the
breath intake
conduit 44 at a first end thereof. A set of metering devices are positioned
along the exhaust
conduit 48, including a hygrometer 52 to measure the humidity in the exhaust
conduit 48.
Condensation can deteriorate the function of the breath sample collection
apparatus 20 in
that components of a person's breath can be trapped by this condensation, thus
not being
correctly represented in the collected breath sample. Further, certain levels
of humidity
and/or condensation can impact the function of other components of the breath
sample
collection apparatus 20. A capnometer 56 is positioned along the exhaust
conduit 48 to
measure the carbon dioxide content of a patient's breath. Also positioned
along the exhaust
conduit 48 is a flow meter 60 that determines the flow rate of the breath
along the exhaust
conduit 48. A low-pressure resistance portion 64 along the exhaust conduit 48
provides a
low amount of resistance to the flow of gas along the exhaust conduit 48
towards an exhaust
conduit outlet 68 at a second end of the exhaust conduit 48. The low-pressure
resistance
portion 64 acts as a cap on the exhaust conduit 48 and inhibits return
diffusion gas from
entering the exhaust conduit 48 while allowing gas to flow in both directions
if needed. Any
suitable structure can be employed to provide the low-pressure resistance
portion 64, such
as a flexible or hinged flap, a section of conduit having a restricted cross-
section or
change(s) in direction, etc.
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[0099] An air circulation system includes a pump conduit 76 that
branches from the
exhaust conduit 48 and terminates at a pump 72 that is driven by a motor. The
pump 72 is
configured to draw ambient air in and through the exhaust conduit 48 and the
breath intake
conduit 44, such as via the mouthpiece 36, and expel it into the surrounding
environment,
when needed. Any fluid pump that is suitable for use with gases can be
employed.
[0100] The inner diameter size of the mouthpiece 36 and the conduit
portions 44, 48 are
selected to provide only insignificant resistance to the exhalation of breath
through the
mouthpiece 36. Further, the conduit portions 44, 48 can be heated or cooled as
desired to
control the formation of condensation therealong. This can be desirable so
that
condensation is less likely to pass through to the breath sample collection
devices, such as
sorbent tubes.
[0101] A breath collection valve 80 is connected to the breath
intake conduit 44 and
controls the flow of a gas from the breath input interface 24 of the breath
intake conduit 44
to a breath collection conduit 84 of the breath capture conduit system 82. The
breath intake
conduit 44 forms part of the direct path between the breath input interface 24
and the breath
capture conduit system 82. An intake valve 88 controls the flow of gas
entering or exiting
the breath collection conduit 84 via an ambient air inlet 92. An air filter 96
is positioned
between the ambient air inlet 92 and the intake valve 88 and filters incoming
ambient air to
inhibit the entry to particulate contamination therein.
[0102] A container is in fluid communication with the breath
collection conduit 84 and is
configured to store breath received from the breath collection conduit. The
container in this
embodiment includes a piston chamber 100 having a cavity 104 therein defined
at least
partially by interior walls of the piston chamber 100. The piston chamber 100
has a two-liter
capacity and can have any suitable cross-sectional shape. A piston 108
corresponds in
shape to and is positioned within the piston chamber 100 and is driven by a
piston motor
112. The piston 108 seals against the sides of the piston chamber 100 to
provide an airtight
seal. The piston motor 112 can be any suitable type of motor to actuate the
piston 108 within
the piston chamber 100.
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[0103] The volume of the cavity 104 is directly mechanically
controllable by the
positioning of the piston 108 within the piston chamber 100 by the piston
motor 112. Further,
the volume change rate of the cavity 104 is controllable by actuating the
piston 108 within
the piston chamber 100 at a corresponding rate to either increase the volume
of the cavity
104, defining a volume increase rate, by moving further into the piston
chamber 100, or
decrease the volume of the cavity 104, defining a volume decrease rate, by
moving further
out of the piston chamber 100.
[0104] In another embodiment, the piston chamber is constructed with
an interior space,
and the piston has a similar profile to slidingly move through the interior
space of the piston
chamber.
[0105] The breath collection conduit 84 is connected to a tube
manifold 116. The tube
inlet manifold 116 branches to four tube inlet valves 120. A bypass conduit
124 branches
from the breath collection conduit 84 and has a bypass valve 128 positioned
along the
bypass conduit 124 to prevent or allow the flow of gas therealong. An outlet
valve 132 is
positioned towards an outlet 136 and controls the flow of gas through the
outlet 136. A tube
outlet manifold 140 is connected to the bypass conduit 124 and branches to
four tube outlet
valves 144. The tube inlet valves 120 and the tube outlet valves 144 have
connectors for
receiving sorbent tubes. In other embodiments, the breath sample collection
apparatus 20
can be configured to receive and use any number of sorbent tubes.
[0106] A controller 148 controls operation of the breath sample
collection apparatus 20.
The controller 148 is connected to the valves 80, 88, 120, 128, 132, and 144
to open and
close these valves as described herein below. In other embodiments, the
functionality of the
controller 148 can be performed by two or more controllers.
[0107] A display 150 is controlled by the controller 148 to present
instructions and
information to a person, as well as metrics collected by the breath sample
collection
apparatus 20, such as the completeness of the procedure, the estimated amount
of time
remaining, etc.
[0108] The internal components with which the breath comes into
contact are generally
inert. The conduits and valves are made of stainless steel and have an inert
coating. Sealing
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elements within the valves are made of FKM, a family of fluoroelastomer
materials, or
another suitable resilient material that has a very low rate of off-gassing.
While the
polypropylene mouthpiece 36 can off-gas, the level is within an acceptable
tolerance level.
[0109] Referring now to FIG. 2, an exemplary sorbent tube 152 is
shown. The sorbent
tube 152 has a stainless-steel casing 156 that is tubular, defining an
aperture 160 at each
end thereof. A receiving end 164 of the sorbent tube 152 receives a gaseous
fluid to be
adsorbed. In the exemplary described embodiment, the gaseous fluid is human
breath
collected from a human for testing. A foam separator 168 is positioned towards
the receiving
end and is configured to distribute fluid pressure more evenly across the
cross-section of
the stainless-steel casing 156. An adsorbent material 172 is positioned
adjacent to the foam
separator 168 and another foam separator 110. The separators may alternatively
be made
of a wire mesh or other suitable material. The adsorbent material 172 is very
porous, has a
relatively high surface area, and is selected for sampling specific compounds
to trap and
retain the compounds of interest even in the presence of other compounds.
Further, the
adsorbent material 172 allows the collected compounds to be easily desorbed or
extracted
for analysis. In addition, the solid adsorbent which is selected does not
react with the sample.
In the particular example, the solid adsorbent is Tenax TA or a carbon
material. As a
gaseous fluid is received via the receiving end 164, the sample is more
concentrated
towards the receiving end 164 of the sorbent tube 152. In other embodiments,
the
composition and configuration of the sorbent tubes can vary, as will be
appreciated by a
person skilled in the art.
[0110] A method 200 of collecting a breath sample using the breath
sample collection
apparatus 20 will now be discussed with reference to Figs. 1, 3, and 4A to 4G.
[0111] The method 200 commences with the drawing in of ambient air
into the system
(210). The system is flushed of any stale residual air by drawing ambient air
in and then
expelling it through the conduits 44, 48, 68, 76, 84, and 124. This is done to
ensure that
there is no cross-contamination from breath from a previous person with breath
being
presently collected. Stale room air in the system is replaced with fresh room
air during this
flush.
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[0112] First, it is ensured that the valves 80, 120, and 128 are
closed. Then the controller
148 directs the intake valve 88 to open, and the piston motor 112 to operate
to withdraw the
piston 108 in the piston chamber 100. As the piston 108 is withdrawn in the
piston chamber
100, the cavity 104 defined by the interior walls of the piston chamber 100
and the piston
108 which is airtight sealed thereagainst increases in volume. As a result,
the pressure
within the cavity 104 rapidly decreases. Ambient air is drawn in through the
ambient air inlet
and the air filter 96, and into the cavity 104.
[0113] FIG. 4A shows the cavity 104 filled with ambient air that has
been drawn in. For
purposes of illustration hereinafter, valves that are open will include
stippling and valves that
are closed will be free of stippling. The air filter 96 removes particulate
from the ambient air
as it is drawn in and before it enters the breath collection conduit 84. While
the breath
collection valve 80 is closed during this intake of ambient air, traces of
breath from a previous
person may be present along the breath intake conduit 44 and along the exhaust
conduit
48. It is desirable to maintain the breath collection valve 80 closed so that
only ambient air
with drawn in and so that it is filtered via the air filter 96.
[0114] Upon drawing the ambient air into the piston chamber 100, the
ambient air is used
to flush the system (208). The controller, upon withdrawing the piston 108 in
the piston
chamber 100, closes the intake valve 88 and then opens all the other valves.
Once the
valves 80, 120, 128, 132, and 144 have been opened, the controller 148 directs
the piston
motor 112 to drive the piston 108 into the piston chamber 100 to force the
ambient air therein
through the breath intake conduit 44 and out the mouthpiece 36, through the
exhaust conduit
48 and out the exhaust conduit outlet 68, through the breath collection
conduit 84 and the
tube inlet manifold 116 and out the tube inlet valves 120, and through the
bypass conduit
124 and the tube outlet manifold 140 and out the outlet 136 and the tube
outlet valves 144.
As a result, the conduits of the system are effectively filled with ambient
air.
[0115] FIG. 4B shows the flushing of the breath sample collection
apparatus 20.
[0116] After the system has been flushed with ambient air, the
valves 80, 120, 132, and
144 are closed again.
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[0117] Upon completing the flush, the controller 148 determines if
the flush is to be
repeated (212). The flush is repeated five to ten times, with about ten to 20
liters of air to
reduce the probability of breath from a previous person contaminating the
breath sample to
be taken. If it is determined that the required number of flushes has not yet
been completed,
the controller 148 commences the process of drawing in ambient air again at
204.
[0118] If, instead, it is determined that sufficient flushes have
been performed, one or
more sorbent tubes 152a to 152d (alternatively, collectively referred to
hereinafter as sorbent
tubes 152) are loaded into the breath sample collection apparatus 20 (213).
The bypass
valve 128 and the outlet valve 132 are closed. One to four sorbent tubes 152
are then loaded
into the breath sample collection apparatus 20.
[0119] In this embodiment, samples of ambient air are used as
controls to which the
breath sample can be compared. The ambient air that is breathed in by a person
during the
providing of a breath sample may contain some compounds that will register
during analysis
of the breath sample. In order to identify these compounds in the ambient air
in the space
in which the breath sample collection apparatus 20 is situated, ambient air
can be adsorbed
in one or more sorbent tubes 152. The breath sample collection apparatus 20
performs
ambient air collection in a somewhat similar manner to breath collection.
Thus, at least two
sorbent tubes 152 are loaded so that at least one can capture ambient and at
least another
can capture breath.
[0120] Once the sorbent tubes are loaded, ambient air is drawn into
the piston chamber
100, as is shown in FIG. 40 (214). Ambient air from the room in which the
breath sample
collection apparatus 20 is drawn in by controlling the piston motor 112 to
actuate the piston
108. As the piston 108 is withdrawn in the piston chamber 100, the size of the
cavity 104
increases and ambient air is pulled into the cavity 104 via the inlet 92,
through the air filter
96 and the inlet valve 88.
[0121] Once the ambient air has been drawn into the piston chamber
100, the ambient
air is flowed through a subset of the sorbent tubes 152, as shown in FIG. 4D
(215). The
controller 148 opens a first of the tube inlet valves 120 and a first of the
tube outlet valves
144, as well as the outlet valve 132. Next, the controller 148 directs the
piston motor 112 to
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actuate the piston 108 to move into the piston chamber 100 to decrease the
volume of the
cavity 104. As the cavity volume decreases, the ambient air in the cavity 104
is impelled
through a first sorbent tube 152a and out through the outlet 136. The rate at
which the
ambient air is flowed through the sorbent tube 152a is selected to provide
effective
adsorption while being time-efficient.
[0122] If it is determined that a target volume of ambient air to be
flowed through the
sorbent tube 152a in order to capture the ambient air sample exceeds the
capacity of the
piston chamber (about two liters), 214 and 215 are repeated as needed until
the ambient air
sample has been captured in the sorbent tube 152a.
[0123] Next, a person 180 from which a breath sample is being
collected is directed via
the display 150 to exhale into the mouthpiece 36 during a process referred to
as "breath
pre-collection", as is shown in FIG. 4E (216). "Breath pre-collection" is used
to accustom the
person 180 with the sensation of exhaling into the breath sample collection
apparatus 20 in
a specified manner according to criteria set out for operation of the breath
sample collection
apparatus 20. The display 150 presents instructions to the person 180
regarding a target
exhalation rate of 20 liters per minute. By accustoming the person 180 on how
to exhale into
the breath sample collection apparatus 20, the person 180 typically becomes
more
consistent in their breaths. People typically are much better able to control
their exhalation
rate after performing even just one breath exhalation of training. In
addition, the breath
provided during the breath pre-collection phase is used to prime the conduits
of the system.
[0124] As the breath collection valve 80 is closed, the breath
exhaled by the person 180
travels through the breath intake conduit 44 and along the exhaust conduit 48.
[0125] During the breath pre-collection phase, the capnometer 56 is
sampling the air to
determine the level of carbon dioxide therein. As the capnometer 56 is
sampling the air
frequently, the capnometer 56 can also determine the rate of change of the
level of carbon
dioxide. The flow meter 60 determines the flow rate of the breath. The low-
pressure
resistance portion 64 provides very low flow restriction to exhalation by the
person 180, and
the breath exits through the exhaust conduit outlet 68.
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[0126] The controller 148 constantly monitors signals from the
capnometer 56 and the
flow meter 60 to determine if a set of breath collection criteria are met.
These breath
collection criteria are (a) the carbon dioxide level reported by the
capnometer 56 is within a
target range defined by a minimum threshold and an infinite upper bound; (b)
the rate of
change of the carbon dioxide level is within a change rate target range
defined by an infinite
lower bound and a change rate maximum threshold; and (c) the flow rate of the
breath
exhalation is within a target range defined by a minimum flow rate threshold
and a maximum
flow rate threshold. In the present embodiment, the minimum flow rate
threshold is 20 liters
per minute and the maximum is 25 liters per minute. Having the flow rate of
breath be within
a target range provides consistency to the breath provided by the person 180.
As will be
understood, it can be said that the target ranges can be defined by a
threshold at one of its
bounds as the other bound can be logically satisfied, such as an infinite or
zero bound.
[0127] The first part of the breath of the person 180 includes air
from the mouth or and/or
throat for which oxygen/carbon dioxide exchange did not occur in the lungs,
thereby giving
it a higher percentage of oxygen. As the person 180 continues to breath out, a
greater
portion of the breath is from the lungs where oxygen/carbon dioxide exchange
occurs. As a
result, the carbon dioxide released from the blood stream becomes a larger
contingent
(about 3-7%) of the breath. Then the carbon dioxide level hits a knee when the
change rate
thereof decreases dramatically. This indicates that the breath is from inside
the lungs,
instead of the breath from the mouth or the windpipe/trachea. This breath is
referred to as
alveolar breath. In the present embodiment, the target range for the carbon
dioxide level is
from 3% of the breath to an infinite upper bound, and the change rate target
range for the
carbon dioxide level is from 0% to 2% of the breath per second.
[0128] FIG. 5 shows the carbon dioxide level in exhaled breath over
time relative to a
threshold 0. The rate of change of the carbon dioxide level is generally
consistently elevated
until alveolar breath is being exhaled, at which point the rate of change in
the carbon dioxide
level drops significantly, This change of rate is reflected as a knee K.
Thereafter, the carbon
dioxide level in the exhaled alveolar breath is stable.
[0129] In the present configuration, the breath collection criteria
are as follows. The
carbon dioxide level is above a threshold of 2%. This level is well above
atmospheric levels,
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but below what is expected to be seen in a person (e.g., 3% is lowest from
people with poor
lung function). The rate of change of the carbon dioxide level is below a
specified threshold.
Further, the flow rate of the breath exhalation exceeds 20 liters per minute.
[0130] The three criteria prevent the trigger of breath collection
during less-than-ideal
circumstances in many cases.
[0131] Upon the satisfaction of all three criteria, breath
collection commences as is
illustrated in FIG. 4F (224). Once the three criteria are satisfied, the
controller 148 opens the
breath collection valve 80 and directs the piston motor 112 to drive the
piston 108 to increase
the volume of the cavity 104 as the breath is being received. The piston 108
is controlled to
actuate at a rate dependent upon the flow rate reported by the flow meter 60
to provide a
volume increase rate for the cavity 104. In this particular embodiment, the
volume increase
rate of the cavity 104 achieved as a result of actuating the piston 108 is
proportional to the
flow rate detected by the flow meter 60 along the exhaust conduit 48. In other
embodiments,
the volume change rate of the cavity 104 can be changed in a different manner
as a function
of the flow rate reported by the flow meter 60.
[0132] As the volume of the cavity 104 increases, it is easier for
the person 180 to exhale
due to the pressure differential created. If the person 180 is exhaling at 20
liters per minute,
the person 180 is only breathing out with force required for four liters per
minute as 16 liters
per minute are being pulled out by the pressure differential in the system as
a result of the
increasing volume of the cavity 104. This can enable people with reduced
ability to exhale
with force to provide a breath sample, such as can be the case with lung
cancer and
respiratory conditions.
[0133] As previously indicated, the flow meter 60 is positioned
along a normally
downstream path for airflow to inhibit the contamination of a presently
collected breath
sample with breath from a previous breath sample provider that adhered to the
flow meter
60. If the actuation rate of the piston 108, and thus the increase rate of the
cavity volume,
were fixed, more or less of the breath would be expelled via the flow meter 60
when the
person 180 exhaled more rapidly. This can result in a more-than-desired amount
of the
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exhaled breath escaping along the exhaust conduit 48, and issues when the flow
rate drops
below the volume increase rate of the cavity 104.
[0134] In the present configuration, the controller 148 controls the
piston 108 to increase
the volume of the cavity 104 at a rate that is dependent on the flow rate
measured by the
flow meter 60. In particular, the volume of the cavity 104 is increased at
four times the flow
rate measured by the flow meter 60. That is, the increase in volume of the
cavity 104
captures 80% of the breath received from the person 180.
[0135] The hygrometer 52, the capnometer 56, and the flow meter 60
are all positioned
along the exhaust conduit 48, away from the breath intake conduit 44. These
metering
devices can off-gas VOCs. Further, these metering devices can become
contaminated by
the breath of a person from which breath was previously collected. By placing
these
metering devices along the exhaust conduit 48, along which breath flows away
from the
direct path along the breath intake conduit 44, contamination by the other
breath or off-
gassed VOCs is inhibited. Further, these metering devices and the conduits are
provided
with an inert internal coating to reduce the probability that breath or off-
gassed VOCs adhere
to their internal surfaces to thereby further reduce the probability of
contamination of a breath
sample by the previously received breath and off-gassed VOCs.
[0136] By allowing some of the breath received to travel along the
exhaust conduit 48
along which the hygrometer 52, the capnometer 56, and the flow meter 60 are
located, the
overall generally unrestricted breath exhalation rate can be determined. This
breath
exhalation rate is equal to the flow rate measured by the flow meter 60 plus
the rate of
increase of the volume of the cavity 104 determined based on the actuation
rate of the
position of the piston 108. This breath exhalation rate can then be used to
determine how
fast to increase the volume of the cavity 104. By keeping the rate of increase
of the volume
of the cavity 104 below the determined breath exhalation rate, some of the
breath will always
travel down the exhaust conduit 48 to enable continued monitoring of the
overall breath
exhalation rate.
[0137] This ratio of 80% of the overall breath exhalation rate has
been selected to afford
a reaction time buffer so that if the exhalation rate of the person quickly
drops off, the volume
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increase rate of the cavity 104 can be adjusted with a minor amount of lag
with very little
chance of exceeding the breath exhalation rate. If the volume increase rate of
the cavity 104
exceeds the breath exhalation rate of the person, the pressure differential in
the system may
draw breath from the person unnaturally, which can be an undesirable outcome,
and can
draw in ambient air through the exhaust conduit outlet 68.
[0138] Information regarding the overall exhalation rate is
presented to the person 180
on the display 150 to encourage the person 180 to exhale within the target
range or at least
at the threshold rate.
[0139] If the person 180 increases their exhalation rate, up to a
threshold 25 liters per
minute, the piston 108 is actuated by the controller to move to cause the
cavity 104 to
increase in volume so that 80% of the exhaled breath is collected within the
cavity 104.
[0140] If the person 180 reduces their exhalation rate, the piston
speed is adjusted so
that the change in volume of the cavity 104 is always below the rate of
exhalation to ensure
that no air is pulled in via the flow meter route and that the flow rate of
breath can be metered
via the flow meter 60.
[0141] If the flow rate detected by the flow meter 60 falls within a
flow rate termination
range, movement of the piston 108 is stopped to stop the collection of breath
in the piston
chamber 100. The flow rate termination range in the present embodiment is from
an infinite
lower bound to two liters of breath per minute.
[0142] The person 180 may not have enough breath to fill the entire
piston chamber 100.
Accordingly, once the flow meter 60 reports that the exhalation rate drops
below a certain
value, movement of the piston 108, and thus breath collection, is stopped.
[0143] The controller 148 then determines if a target volume has
been collected to prime
the system (228). The breath sample collection apparatus 20 collects one liter
of breath to
prime the system. If less than the target volume of one liter of breath has
been collected, the
controller 147 controls the breath sample collection apparatus 20 to perform
breath pre-
collection at 216.
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[0144] If, instead, it is determined at 228 that sufficient breath
has been collected to
prime the system, the collected breath is used to prime the system, as is
shown in FIG. 4G
(232). The controller 184 directs the breath collection valve 80 to close, and
the bypass
valve 128 and the outlet valve 132 to open. Further, the piston motor 112 is
directed to drive
the piston 108 into the piston chamber 100, thereby reducing the volume of the
cavity 104.
As the volume of the cavity 104 is reduced (i.e., the volume decrease rate),
the breath
contained therein is impelled through the breath collection conduit 84, the
tube inlet manifold
116, the tube outlet manifold 140, the bypass conduit 124, and out the outlet
136. This
primes these conduits with the collected breath of the person 180.
[0145] Upon priming the capture conduit system 82, breath is
collected again using the
same general approach at 216 to 228. That is, breath pre-collection is
performed again
(240). During breath pre-collection, the controller 148 determines if the
breath exhalation
criteria are satisfied (244). If they are, breath is collected as is shown in
FIG. 4H (248).
[0146] Then it is determined if a target volume of breath for
adsorbing has been collected
or if the piston chamber 100 is full (252). If the target volume of breath for
adsorbing in the
sorbent tube(s) 152 has not yet been collected and if the piston chamber 100
is not full,
more breath is collected again starting with breath pre-collection at 240. The
person 180 is
instructed to take another breath.
[0147] If, instead, it is determined that the target volume of
breath has been collected or
that the piston chamber 100 is full at 252, the breath is flowed through a
second subset of
the sorbent tubes 152 (256). FIG. 41 illustrates the piston chamber 100 having
been filled
with breath. The controller 148 is configured to control a flow of the at
least some of the
breath from the container to a subset of the sorbent tubes 152 asynchronous of
when the
exhaled breath is received. That is, the flowing of breath from the container
to a subset of
the sorbent tubes 152 can be performed independent of when the exhaled breath
is
received, apart from having to occur after receiving the exhaled breath. The
second subset
can be any number of the sorbent tubes 152 connected to the breath sample
collection
apparatus 20 that have not been adsorbed with ambient air. Once the machine
has collected
a full piston chamber 100 of breath after priming the conduits, the controller
148 closes the
breath collection valve 80, and controls each of the tube inlet valves 120,
either leaving the
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tube inlet valves 120 in their previously closed or open state or opening or
closing each of
the tube inlet valves 120, to select a subset of the sorbent tubes 152 through
which the at
least some of the breath is flowed through. In this embodiment, the controller
148 opens a
corresponding one of the tube inlet valves 120 and the tube outlet valves 144
for a sorbent
tube 152 in which the sample is to be adsorbed, as well as the outlet valve
132. The piston
108 is controlled by the controller 148 to slowly move to push the breath
therein through the
selected sorbent tube 152 at a predetermined rate pushing breath through the
designated
sorbent tube 152.
[0148] As the breath is being flowed through the second subset of
sorbent tubes 152, air
is simultaneously flowed through the pre-collection conduit system 46 to
reduce
condensation therein (260). In particular, the controller 148 controls the
pump 72 to turn on
to draw ambient air from the mouthpiece 36 and the exhaust conduit outlet 68
and through
the exhaust conduit 48 to help relieve condensation out of the line. As the
measurement
equipment does not work optimally in very humid conditions, the pump 72 acts
to lower
condensation/humidity in the exhaust conduit 48. As the pump 72 is operated,
the humidity
level is monitored via the hygrometer 52.
[0149] FIG. 6 shows a typical graph of humidity level detected by
the hygrometer 52 over
time. Before the pump 72 is turned on at ti, the humidity is at a first level
hi. High levels of
condensation can be observed in the clear mouthpiece 36. After the pump 72 is
turned on,
the change rate in the humidity level is negative as the humidity level drops
overtime. When
the change rate of the humidity level is within a change rate target range at
time t2, the
controller 148 terminates operation of the pump 72, as it is deemed that the
pre-collection
conduit system 46 is relatively free of condensation and that continued
operation of the
pump 72 has relatively little value. This humidity level change rate target
range in the present
embodiment is -0.05% relative humidity per second to 0% relative humidity per
second, but
can be varied in other scenarios. In this manner, the breath sample collection
apparatus 20
can perform maintenance during otherwise idle time. In other embodiments, this
condensation reduction phase can be run based on a humidity level being
outside of a
humidity level target range of values from zero to the humidity level of the
ambient air via
use of a secondary external hygrometer.
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[0150] The rate at which the breath is flowed through the sorbent
tube 152 is 500
milliliters per minute. It has been found that the break-through volume for
the sorbent tube
152 is affected by the adsorb flow rate. The break-through volume is the
volume at which
half of the sample is captured by a sorbent tube 152 and the other half flows
through to the
other side of the sorbent tube 152. At the break-through volume, the adsorbent
in the sorbent
tube 152 is at the point where enough surface is used so that it is just as
easy for molecules
to go through as it is for molecules to be trapped. Increasing the flow rate
of breath through
a sorbent tube 152 decreases the break-through volume. This skews the captured
sample
to the heavier molecules and less of the smaller molecules. By controlling the
flow rate of
the breath through the sorbent tubes 152, the adsorption rate for certain
molecules can be
controlled.
[0151] It is then determined if a target volume has been flowed
through the subset of
sorbent tubes 152 (264). If a desired amount of breath has not yet been flowed
through the
subset of sorbent tubes 152, the method 200 returns to 240, at which more
breath is
collected for flowing through the subset of the sorbent tubes 152.
[0152] Upon determining that a target volume has been flowed through
the currently
selected sorbent tube 152, the controller 148 can terminate flowing the breath
through the
sorbent tube 152 via the tube inlet and outlet valves 120, 144 and commence
flowing the
breath through another of the sorbent tubes 152.
[0153] The breath sample collection apparatus 20 can be configured
to select different
sized subsets of the sorbent tubes for ambient air and breath samples. In one
preferred
embodiment, two sorbent tubes of ambient air samples and two sorbent tubes of
breath
samples are collected. In other embodiments, no ambient air may be collected.
[0154] While not explicitly illustrated, it will be understood that
the controller 148 is
connected to each of the valves, the hygrometer 52, the capnometer 56, the
flow meter 60,
the pump 72, the piston motor 112, as well as other components of the breath
sample
collection apparatus 20.
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[0155] In other embodiments, the container with a controllable
volume can be any other
structure for providing a cavity with a controllable volume. For example, in
one particular
embodiment, the container can include a bellows-like structure.
[0156] FIG. 7A shows a breath sample collection apparatus 300 in
accordance with
another embodiment. The breath sample collection apparatus 300 is similar to
the breath
sample collection apparatus 20 of FIGS. 1 and 4A to 41, except that the breath
sample
collection apparatus 300 employs a two-way pump 304 and a container that
includes an at
least partially flexible collapsible receptacle 308 in place of the piston
chamber 100 and
piston 108. The at least partially flexible collapsible receptacle 308 is
secured to the two-
way pump 304 that is, in turn, secured to the breath collection conduit 84.
[0157] In this embodiment, the at least partially flexible
collapsible receptacle 308 is a
bag made of polyvinyl fluoride, a highly flexible material that has high
tensile characteristics.
While not impermeable, It has a suitably low permeability that, for this
application, does not
impact its performance significantly. Further, it is relatively inert. Other
suitably flexible,
relatively non-porous, and relatively inert materials can additionally or
alternatively be used
in other embodiments. Further, the receptacle can also include inflexible
portions.
[0158] The at least partially flexible collapsible receptacle 308
has an interior cavity that
has a volume defined by the amount of a fluid therein. In FIG. 7A, the at
least partially flexible
collapsible receptacle 308 is shown having substantially no breath or ambient
air therein,
and thus the cavity has substantially no volume. In this collapsed state, the
at least partially
flexible collapsible receptacle 308 can be compacted to facilitate packing.
[0159] The two-way pump 304 has a controllable flow rate and flows
breath and/or
ambient air in both directions. It is controllable by the controller 148 to
draw breath and/or
ambient air from the breath collection conduit system 82 into the at least
partially flexible
collapsible receptacle 308, and draws breath and/or ambient air from the at
least partially
flexible collapsible receptacle 308 into the breath collection conduit system
82. Thus, the
controller 148 can control the two-way pump 304 and, as a result, the at least
partially flexible
collapsible receptacle 308 to provide the same general functionality as the
piston chamber
100, the piston motor 112, and the piston 108. That is, the controller 148
can, through
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operation of the pump, control the volume of the at least partially flexible
collapsible
receptacle 308.
[0160] FIG. 7B shows the at least partially flexible collapsible
receptacle 308 after the
two-way pump 304 has drawn breath and/or ambient air therein, thus enlarging
the cavity
of the at least partially flexible collapsible receptacle 308 and the at least
partially flexible
collapsible receptacle 308 itself.
[0161] The breath sample collection apparatus 300 also differs in
that it has an array of
light elements in the form of LEDs 312 and an audio speaker 316 in place of a
display. Flow
rate notifications can be presented to a user via the LEDs 312. For example,
the array of
LEDs 312 can include a sequence of a red LED, a yellow LED, a green LED, a
yellow LED,
and a red LED. When the flow rate of breath through the breath input interface
24 is too low,
a corresponding red or yellow LED can be illuminated. If the flow rate of
breath through the
breath input interface 24 is satisfactory, the green LED can be illuminated.
Similarly, when
the flow rate of breath through the breath input interface 24 is too high, a
corresponding
second red or yellow LED can be illuminated. In this manner, a person can be
shown visually
how his breath flow rate compares to a target flow rate. In other embodiments,
other types
of light elements can be employed.
[0162] The audio speaker 316 can be used in a similar manner, with
flow rate
notifications being provided by means of clicks of different frequencies,
sounds of different
frequencies, different sounds, etc.
[0163] FIG. 8 shows a breath sample collection apparatus 400 in
accordance with a
further embodiment. In this embodiment, the flow meter 60 is positioned along
the breath
intake conduit 44. Thus, the flow meter 60 measures the full exhaled breath
rate along the
breath intake conduit 44. During breath collection, the controller 148 can
control the piston
motor 112 to actuate the piston 108 so that the volume change rate of the
cavity 104 is set
to a proportion of the flow rate measured by the flow meter 60. In a preferred
embodiment,
the volume change rate of the cavity 104 is set to 80% of the flow rate
measured by the flow
meter 60 during breath collection. The excess breath flows along the exhaust
conduit 48
and out the exhaust conduit outlet 68.
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[0164] While, in the above-described embodiments, a capnometer is
employed to
measure the level of carbon dioxide in the breath, in other embodiments, other
types of
metering devices can be employed for measuring the levels of other
constituents in the
breath, such as those that can indicate when alveolar breath is being
detected. These
metering devices can detect levels and change rates in these levels of these
other
constituents to determine when alveolar breath is being detected. For example,
a metering
device can measure an oxygen level in the breath and, upon detecting that the
change in
the oxygen level has fallen within a change rate target range having a change
rate maximum
threshold, it can be determined that alveolar breath is now being detected.
[0165] In other embodiments, other types of breath sample storage
devices apart from
sorbent tubes can be employed. For example, solid-phase microextraction
("SPME") fibres
can be alternatively used to store the breath sample. Another example is
silica gel. Still other
examples are powders that produce a chemical reaction resulting in a visible
indication (e.g.,
Drierite turns purple in the presence of humidity) or a by-product chemical
that can be more
easily analyzed later. Other types of breath sample storage devices will occur
to those skilled
in the art.
[0166] The volume of the container can be mechanically controlled in
other manners. In
one particular embodiment, the container can include a bellows that can be
actuated to
expand and contract.
[0167] Although specific advantages have been enumerated above, various
embodiments may include some, none, or all of the enumerated advantages.
[0168] Persons skilled in the art will appreciate that there are yet
more alternative
implementations and modifications possible, and that the above examples are
only
illustrations of one or more implementations. The scope, therefore, is only to
be limited by
the claims appended hereto.
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LIST OF REFERENCE NUMERALS
20 breath sample collection apparatus
24 breath input interface
36 mouthpiece
40 breath intake end
44 breath intake conduit
46 pre-collection conduit system
48 exhaust conduit
52 hygrometer
56 capnometer
60 flow meter
64 low-pressure resistance portion
68 exhaust conduit outlet
72 pump
76 pump conduit
80 breath collection valve
82 capture conduit system
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84 breath collection conduit
88 intake valve
92 ambient air inlet
96 air filter
100 piston chamber
104 cavity
108 piston
112 piston motor
116 tube inlet manifold
120 tube inlet valve
124 bypass conduit
128 bypass valve
132 outlet valve
136 outlet
140 tube outlet manifold
144 tube outlet valve
148 controller
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150 display
152 sorbent tube
156 stainless-steel casing
160 aperture
164 receiving end
168 foam separator
172 adsorbent material
176 foam separator
180 person
200 method
204 draw ambient air
208 flush system
212 repeat flush?
213 load sorbent tubes
214 draw ambient air
215 flow air through first subset of sorbent tubes
216 breath pre-collection
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220 breath exhalation criteria satisfied?
224 breath collected to prime system
228 target volume?
232 prime system with collected breath
236 load sorbent tubes
240 breath pre-collection
244 breath exhalation criteria satisfied
248 collect breath
252 target volume or container full?
256 flow breath through sorbent tube(s)
260 flow air through pre-capture conduit system to reduce
condensation
264 target volume?
300 breath sample collection apparatus
304 two-way pump
308 flexible collapsible receptacle
312 LEDs
316 speaker
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