U.S. patent application number 13/482848 was filed with the patent office on 2012-11-01 for volume-adjustable manual ventilation device.
This patent application is currently assigned to ARTIVENT CORPORATION. Invention is credited to Ian Halpern.
Application Number | 20120272965 13/482848 |
Document ID | / |
Family ID | 40720358 |
Filed Date | 2012-11-01 |
United States Patent
Application |
20120272965 |
Kind Code |
A1 |
Halpern; Ian |
November 1, 2012 |
VOLUME-ADJUSTABLE MANUAL VENTILATION DEVICE
Abstract
Disclosed is a manually operable volume-adjustable ventilation
device. The device includes a reservoir with an inlet mechanism, an
outlet mechanism, and a volume adjuster configured to move a volume
adjustment limit of the reservoir and change an expressed maximum
volume of the reservoir. The reservoir has a body having a
plurality of movable walls defining an enclosed volume. The
reservoir has an uncompressed state and a compressed state. The
walls of the reservoir are movable with respect to each other, such
that moving the walls expresses the volume adjustment limit of the
reservoir.
Inventors: |
Halpern; Ian; (San
Francisco, CA) |
Assignee: |
ARTIVENT CORPORATION
San Francisco
CA
|
Family ID: |
40720358 |
Appl. No.: |
13/482848 |
Filed: |
May 29, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12698928 |
Feb 2, 2010 |
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13482848 |
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11635381 |
Dec 6, 2006 |
7658188 |
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12698928 |
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11147070 |
Jun 6, 2005 |
7537008 |
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11635381 |
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12698928 |
Feb 2, 2010 |
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11147070 |
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11952094 |
Dec 6, 2007 |
8235043 |
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12698928 |
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Current U.S.
Class: |
128/205.14 |
Current CPC
Class: |
A61M 16/20 20130101;
A61M 16/0084 20140204; A61M 2205/582 20130101; A61M 16/107
20140204; A61M 16/208 20130101; A61M 16/201 20140204; A61M
2016/0027 20130101; A61M 16/0616 20140204; A61M 16/0078 20130101;
A61M 2205/583 20130101; A61M 2205/3331 20130101; A61M 16/06
20130101; A61M 16/0003 20140204; A61M 2205/581 20130101 |
Class at
Publication: |
128/205.14 |
International
Class: |
A61M 16/08 20060101
A61M016/08 |
Claims
1. A manually operable volume-adjustable ventilation device,
comprising: a reservoir with an inlet mechanism, an outlet
mechanism, and a volume adjuster configured to move a volume
adjustment limit of the reservoir and change an expressed maximum
volume of the reservoir; wherein said reservoir comprises a body
having a plurality of movable walls defining an enclosed volume;
wherein said reservoir has an uncompressed state and a compressed
state; wherein said walls are movable with respect to each other,
such that moving said walls expresses the volume adjustment limit
of the reservoir; wherein said walls are operably connected by
movable structures; wherein the device has a configuration
comprising at least four substantially coplanar pairs of movable
walls.
2. The device of claim 1, wherein the device has a configuration
comprising at least five substantially coplanar pairs of movable
walls.
3. The device of claim 1, further comprising a sealing layer
operably connected with the body of the reservoir of the
device.
4. The device of claim 3, wherein the sealing layer comprises a
plurality of redundant folds between at least some of the adjacent
movable walls.
5. The device of claim 1, wherein said movable structures are
configured such that two adjacent walls are configured to rotate
around substantially orthogonal axes with respect to each other
when the reservoir moves from an uncompressed to a compressed
state.
6. The device of claim 1, wherein a movable wall rotates around an
axis that intersects one or more axes that one or more panels
rotate around.
7. The device of claim 1, further comprising a pressure valve
having a control to adjust a pressure setting of the device,
wherein the control comprises indicia to view a selected pressure
setting selected.
8. A volume-adjustable ventilation device, comprising: a body with
rigid panels encompassing a sealed volume with an inlet mechanism
and an outlet mechanism, the rigid panels movable with respect to
each other, wherein the body has a first uncompressed configuration
and a second compressed configuration, wherein the body has at
least a first displacement and a second displacement, and wherein
the second displacement is a function of the first displacement and
the geometry of the panels, wherein a second panel is adjacent to
and extends from a first panel in a first direction, a third panel
is adjacent to and extends from the first panel in a second
direction, and a fourth panel is adjacent to and extends from the
first panel in a third direction.
9. A method of ventilating a patient, comprising: providing a
ventilation device comprising a reservoir with an inlet mechanism,
an outlet mechanism, and a volume adjuster configured to move a
volume adjustment limit of the reservoir and change an expressed
maximum volume of the reservoir; wherein said reservoir comprises a
body having a plurality of rigid movable walls defining an enclosed
volume; wherein said reservoir has an uncompressed state and a
compressed state; wherein said walls are movable with respect to
each other, such that moving said walls expresses the volume
adjustment limit of the reservoir; wherein said walls are operably
connected by movable structures; wherein a first wall and a second
wall rotate about a first axis, and wherein a third wall rotates
around a second axis wherein said second axis is substantially
orthogonal to said first axis when the reservoir moves from an
uncompressed to a compressed state; and actuating the device to
ventilate the patient.
Description
[0001] This application claims the benefit under 35 U.S.C.
.sctn.120 as a continuation of U.S. application Ser. No. 12/698,928
filed on Feb. 2, 2010 and currently pending, which is in turn a
continuation of U.S. application Ser. No. 11/952,094 filed on Dec.
6, 2007 and currently pending. U.S. application Ser. No. 12/698,928
also claims the benefit as a continuation-in-part application of
U.S. patent application Ser. No. 11/635,381, filed Dec. 6, 2006,
now U.S. Pat. No. 7,658,188, which in turn is a
continuation-in-part of U.S. application Ser. No. 11/147,070 filed
Jun. 6, 2005, now U.S. Pat. No. 7,537,008. Each of the
aforementioned priority applications is hereby incorporated by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates generally to manual
ventilation devices.
BACKGROUND OF THE INVENTION
[0003] Manual ventilation or resuscitation is performed on an
individual when they are unable to breathe independently.
Typically, this occurs when an individual is transported from one
section of a hospital to another section such as an emergency room
and an intensive care unit, or in an ambulance. Manual
resuscitation also occurs during cardiopulmonary resuscitation
(CPR), which is a standard technique applied to victims of
cardiopulmonary arrest with the goal to re-establish normal cardiac
and respiratory function.
[0004] Ventilation from a manual resuscitation device is currently
provided by a self-filling elastomeric enclosure or bag. This bag
is compressible by hand, a face-fitting mask (or intubation tube)
in fluid communication with an outlet passage of the bag, and a
one-way valve between the mask and bag to permit only fluid passage
from the bag to the mask. The bag also has an inlet passage,
typically with one opening for air and another, usually smaller
opening for receiving oxygen. By squeezing the bag with their
hand(s), a clinician delivers air or oxygen to an individual, and
then releases the bag to permit it to expand to full size and
thereby draw air or oxygen through the inlet passage.
[0005] The amount of air received by the lungs of the individual
corresponds to the volume of the bag. A larger bag provides a
greater maximum volume of air to be pumped into the individual.
Children and infants typically have smaller lungs than an adult,
and therefore conventional manual resuscitation devices are
provided in different sizes; e.g., infant, child and adult. Each
size provides a different maximum volumetric output of air.
Depending on factors such as physical condition, body size, age,
sex, etc., each individual may require a specific volume of air
(tidal volume), and frequency, and minute ventilation.
[0006] Unfortunately, current manual ventilation or resuscitation
devices are not suitable for the desired monitoring and control of
tidal volume delivery. For instance, the collapsible bag portion of
the resuscitation device allows the user to merely "feel" the
amount of air they are providing to the individual. This provides
them merely a very rough estimate of the volume of air they are
providing and a tactile feel for when the lungs are non-compliant,
i.e. are being pressurized. Although self-filling respiration
(resuscitation) enclosures or bags can be selected on the basis of
known maximum volumes, the volume actually delivered can vary
substantially among several operators, dependent upon factors such
as hand size, number of hands used, technique, enthusiasm and
fatigue. These variations have been shown to be as much as 60
percent of the optimal tidal volume. Frequency can also vary
between users, resulting in potential underventilation or
overventilation.
[0007] Accordingly, what is needed is a single manual ventilation
or resuscitation device that can be used on any patient, regardless
of individual factors such as physical condition, body/lung size,
age and sex.
SUMMARY OF THE INVENTION
[0008] In one aspect, disclosed is a ventilation device that
includes a reservoir having a movable wall defining an enclosed
volume, such that moving the wall expresses an adjustment limit.
Moving the limit results in a change in the expressed maximum
volume of the device.
[0009] In another aspect, disclosed is a single manual ventilation
or resuscitation device. The body of the device has panels, that
can be rigid, that encompass a sealed volume with an inlet
mechanism and an outlet mechanism. The rigid panels are movable
with respect to each other to allow the body to move between an
uncompressed state and a compressed state. Once in compressed state
a volume restoring mechanism is responsible to restore the volume
from the compressed state back to the uncompressed state.
[0010] One of the objectives of the invention is to be able to hold
the body with one hand and to compress the body with that one hand.
To meet this objective, in one embodiment, the body is
characterized by having a displacement in a direction of a hand
displacement (e.g., height of the body) and at least one other
direction (e.g., width of the body) other than this hand
displacement. In another embodiment, the body is characterized by
having a displacement in a direction of a hand displacement (e.g.,
height of the body) and at least two other directions (e.g., width
and length of the body) other than this hand displacement. The
displacement in width and/or length is a function of the height
displacement and the geometry of the rigid panels.
[0011] The axial displacement of a panel is preferably no more than
about 85 mm, preferably no more than about 20-25 mm, and more
preferably no more than about 10-15 mm. Some of the displacements
would have to comfortably fit between the thumb, one or more
fingers and the web of the hand. In other words, the natural range
of a grasping motion of a hand defines these displacements. The
expressed (delivered) volume of the device, in some embodiments,
can be no more than about 500 cc, or no more than about 250 cc
(infant and child), or no more than about 1400 cc (infant to
adult). In another embodiment, the expressed (delivered) volume of
the device can range from about 250-1200 cc (child to adult).
[0012] A size adjuster is included to adjust one or more of the
body displacements to change the dimension of the uncompressed
state or volume. These axial size adjustments can be no more than
about 170 mm, and preferably no more than about 25 mm in some
embodiments. The objective of the size adjuster is to adjust the
displacement to then adjust the volume of e.g., the air delivered
to an individual. Hence the size adjuster is also referred to as a
volume adjuster.
[0013] A frequency adjuster is included to adjust the time to
restore the volume from the compressed state to the uncompressed
state or to adjust the time to compress the volume from the
uncompressed state to the compressed state.
[0014] Feedback mechanisms could be included to provide tactile
feedback, visual and/or audible feedback to the user. An example of
tactile feedback is to include tactile feedback areas, e.g., a
flexible material, to cover an opening in a rigid panel. These
areas allow the user to feel the compression force or lung
resistance. These tactile areas are preferably sized and positioned
to fit a thumb or one or more fingers of the user's hand. An
example of a visual feedback mechanism is to provide the user
feedback over the size (volume) adjustments or the frequency. An
example of an audible feedback mechanism is to provide the user
feedback over e.g., the compression speed, frequency, tidal volume,
setting of the size (volume) adjuster or setting of the frequency
control adjuster.
[0015] One advantage of the device is the ergonomic fit of the body
to a user's hand in both uncompressed and compressed state, which
reduces fatigue to hand and/or arm muscles. Another advantage of
the device is the ability to adjust the volume and/or frequency so
that the user can rely on a more or less constant tidal volume and
tidal rate. Such ability allows one to use the device on any
patient, regardless of individual factors such as physical
condition, body/lung size, age and sex. Yet another advantage is
that multiple devices could easily be stacked or nested with each
other. In exemplary embodiments, the design and geometry could be
configured to include such stacking or nesting capabilities.
[0016] In another aspect, disclosed is a manually operable
volume-adjustable ventilation device. The device has a reservoir
with an inlet mechanism, an outlet mechanism, and a volume adjuster
configured to move a volume adjustment limit of the reservoir and
change an expressed maximum volume of the reservoir. The reservoir
has a body having a plurality of movable walls defining an enclosed
volume. The reservoir has an uncompressed state and a compressed
state. The walls of the reservoir are movable with respect to each
other, such that moving the walls expresses the volume adjustment
limit of the reservoir. The walls can be operably connected by
movable structures configured such that two adjacent walls are
configured to rotate around substantially orthogonal axes with
respect to each other when the reservoir moves from an uncompressed
to a compressed state. In some embodiments, the movable structures
can be hinges, such as snap-fit assembly hinges. The movable
structures and the movable walls can be co-molded together. In some
aspects, the device can include a covering layer of the body of the
reservoir. The covering layer can be a slide-on skin, and/or
comolded or adhered to the walls of the reservoir.
[0017] In some embodiments, the device is configured such that
applying a force to at least one of the walls of the device will
result in the reservoir moving from the uncompressed state to a
fully compressed state. The device can also be configured such that
an expressed volume of the device for a given adjustment limit is
consistently no more than about 10 cc of a disclosed volume setting
on the volume adjuster from compression to compression for a given
force of compression and airway resistance of a patient. The device
can also further include a volume restoring mechanism to restore
the reservoir from the compressed state to said uncompressed state.
The volume restoring mechanism can be, for example, a compression
spring, an extension spring, or a resilient covering layer. The
volume adjuster can include a stop dial.
[0018] In some aspects, the device can further include a frequency
adjuster to adjust the time to restore the reservoir from the
compressed state to the uncompressed state, and/or the time to
compress said reservoir from the uncompressed state to the
compressed state. The device can be configured such that the
maximum change in expressed volume of the reservoir is no more than
about 1400 cc, no more than about 1200 cc, no more than about 500
cc, or no more than about 250 cc in some embodiments. The device
can include tactile feedback areas on one or more of said walls.
The tactile feedback areas can be flexible areas and sized and
positioned to fit a thumb of a hand or one or more fingers of the
hand. The device can also include a visual feedback mechanism. In
some embodiments, the visual feedback mechanism is an expandable
air reservoir operably connected to the inlet mechanism of the
device; the air reservoir having an expandable wall configured to
indicate the presence of air flow through the reservoir. In some
embodiments, the device further includes an audible feedback
mechanism, which is a pop-off valve in some embodiments.
[0019] The device can also include an air filter operably connected
to the inlet of the device. Furthermore, the device can also
include an inflow line with measurement markings to measure an
aspect of the patient and estimate an appropriate expressed volume
based on the measurement. In some aspects, the device can be
compressed in a stored configuration to less than 35% of a fully
expanded volume of the device; wherein the device is configured to
deliver at least 95% of the fully expanded volume of the device
after being stored for at least about 3 years, 5 years, 10 years,
15 years, or more. The device can also be configured such that
three devices can be stacked in a shelf with a shelf height of no
more than about 200 mm, or no more than about 180 mm. The device
can also have a height of no more than about 70 mm and/or a side
panel width of no more than about 50 mm to allow the device to be
comfortably compressed in one hand by an operator.
[0020] In some aspects, also disclosed is a method of ventilating a
patient. The method includes the step of providing a ventilation
device that includes a reservoir with an inlet mechanism, an outlet
mechanism, and a volume adjuster configured to move a volume
adjustment limit of the reservoir and change an expressed maximum
volume of the reservoir. The reservoir can include a body having a
plurality of movable walls defining an enclosed volume. The
reservoir has an uncompressed state and a compressed state. The
walls can be movable with respect to each other, such that moving
the walls expresses the volume adjustment limit of the reservoir.
The walls can be operably connected by movable structures
configured such that two adjacent walls are configured to rotate
around substantially orthogonal axes with respect to each other
when the reservoir moves from an uncompressed to a compressed
state. The method also can include the step of selecting an
appropriate expressed maximum volume setting from the volume
adjuster. In some aspects, the device is connected the inlet of the
device to an air or oxygen source. Also, the outlet of the device
can be connected to a mask or tube configured to interface with a
patient's airway. Next, the device can be actuated from an
uncompressed state to a compressed state by applying a force to at
least one wall of the device. In some aspects, the method includes
the step of releasing the force to allow the reservoir to move back
from the compressed state to the uncompressed state. The reservoir
can moves back from the compressed state to the uncompressed state
by the action of a volume restoring mechanism. As noted above, the
volume restoring mechanism can be, for example, a compression
spring, an extension spring, and a resilient covering layer. The
movable structures can be hinges. The movable structures and the
walls can be co-molded together. The device can be configured such
that the maximum change in expressed volume of the reservoir is no
more than about 1400 cc.
[0021] In some embodiments, selecting an appropriate expressed
maximum volume setting from the volume adjuster involves turning a
stop dial. In some aspects, the method includes the step of
adjusting the time to restore the reservoir from the compressed
state to the uncompressed state or adjusting the time to compress
the reservoir from the uncompressed state to the compressed state.
In some aspects, the method also includes the step of observing a
visual feedback mechanism that indicates the presence of airflow
into the device. The visual feedback mechanism can be, for example,
an air reservoir with an expandable wall configured to indicate the
presence of air flow through the reservoir. In other aspects, the
method includes the step of listening to an audible feedback
mechanism that provides feedback over one or more of the group
consisting of: the compression speed, frequency, and expressed
volume of the device. Also, the method can include the step of
filtering air before air enters the body of the device.
[0022] Also disclosed is a face mask for use with a manually
operable volume-adjustable ventilation device. The mask includes an
inlet, an inner portion operably connected to the inlet, and an
outer portion. The mask can be configured to transform from a first
configuration to fit over an adult's face to a second configuration
to fit over a child's face. The mask can also be configured to
reversibly transform from a first configuration to fit over an
adult's face to a second configuration to fit over a child's face.
The inner portion can include a bi-stable cone movable between a
first stable position to a second stable position. The mask can
also include a tear-away seam between the inner portion and the
outer portion.
[0023] In other embodiments, also disclosed is a face mask for use
with a manually operable volume-adjustable ventilation device; the
mask configured to create a sealing surface on a patient's face,
the sealing surface extending substantially from cephalad at the
base of the nose near the alar sidewalls to caudally under the
mandible.
[0024] In some embodiments, also disclosed herein is a manually
operable volume-adjustable ventilation device, that includes a
reservoir with an inlet mechanism, an outlet mechanism, and a
volume adjuster configured to move a volume adjustment limit of the
reservoir and change an expressed maximum volume of the reservoir.
The reservoir can include a body having a plurality of movable
walls defining an enclosed volume. The reservoir can have an
uncompressed state and a compressed state, wherein said walls are
movable with respect to each other, such that moving said walls
expresses the volume adjustment limit of the reservoir. The walls
can be operably connected by movable structures. The body can
include a first end, a second end, a central portion, a first
transition zone between the first end and the central portion, and
a second transition zone between the central portion and the second
end. The body can decrease in a radial dimension in the first
transition zone between a first point on the first end to a first
point on the central portion, and then increases in radial
dimension from a second point on the first end to a second point on
the central portion in the first transition zone to the first end.
The body can also decrease in a radial dimension in the second
transition zone between a first point on the second end to a third
point on the central portion, and then increase in radial dimension
from a second point on the second end to a fourth point on the
central portion in the second transition zone to the second end.
The device can also include a sealing layer integrated with the
body of the reservoir of the device. In some embodiments, the
covering layer includes a plurality of redundant folds between at
least some of the adjacent movable walls. In some embodiments, the
device has a configuration where the first transition zone
comprises at least four substantially coplanar pairs of movable
walls. The movable structures can be configured such that two
adjacent walls are configured to rotate around substantially
orthogonal axes with respect to each other when the reservoir moves
from an uncompressed to a compressed state. A movable wall can
rotate around an axis that intersects one or more axes that one or
more panels rotate around. In some embodiments, the device can also
include a pressure valve having a control to adjust a pressure
setting of the device, wherein the control includes indicia to view
a selected pressure setting selected. In some embodiments, a
transition zone of the device includes at least 4, 5, 6, 7, 8, or
more movable walls.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows a three-dimensional perspective view of a
manual ventilation device, according to one embodiment of the
invention.
[0026] FIGS. 1A-C are schematic diagrams illustrating movement of
panels of a manual ventilation device in the presence and absence
of movable structures, according to one embodiment of the
invention.
[0027] FIG. 2 shows a side view of the device of FIG. 1, according
to one embodiment of the invention.
[0028] FIG. 3 shows a top view of the device of FIG. 1, according
to one embodiment of the present invention.
[0029] FIG. 4 shows a front view of the body of the device of FIG.
1, according to one embodiment of the invention. The hook-up to a
mask or intubation tube, and outlet is left out for clarity.
[0030] FIG. 5 shows a hand with dimensions for grasping and
operating the device according to one embodiment of the
invention.
[0031] FIG. 6 shows an exploded view of the device of FIG. 1,
according to one embodiment of the invention.
[0032] FIG. 7 shows an example of a size (volume) adjuster of the
device according to one embodiment of the invention.
[0033] FIG. 7A illustrates an exploded perspective cut-away view of
an adjustment dial, according to one embodiment of the
invention.
[0034] FIG. 7B illustrates a horizontal sectional view of an
adjustment dial, according to one embodiment of the invention.
[0035] FIG. 8 shows an example of a mechanism to restore the volume
of the body of the device from a compressed state to an
uncompressed state according to some embodiments of the
invention.
[0036] FIG. 9 shows an example of a frequency adjuster of the
device according to one embodiment of the present invention.
[0037] FIG. 10 shows an example of a visual feedback mechanism
according to one embodiment of the present invention.
[0038] FIG. 11 shows an example of a tactile feedback mechanism
according to one embodiment of the present invention.
[0039] FIG. 12 shows an example of stacking or nesting devices
according to one embodiment of the present invention.
[0040] FIGS. 13A-D illustrate embodiments of visual airflow
indicators that can be used with a volume-adjustable manual
ventilation device, according to some embodiments of the
invention.
[0041] FIG. 14 illustrates an inflow line configured to allow for
measuring an aspect of the patient, according to one embodiment of
the invention.
[0042] FIG. 15 is a perspective view of a ventilation device,
according to one embodiment of the invention.
[0043] FIG. 16 is an exploded view of the ventilation device
illustrated in FIG. 15.
[0044] FIG. 17A is a side view of the ventilation device of FIG. 15
in an uncompressed state, with the covering layer removed for
clarity.
[0045] FIG. 17B is a side view of the ventilation device of FIG. 15
in a compressed state.
[0046] FIGS. 18A-B are top horizontal sectional views of the
ventilation device of FIG. 15 in uncompressed and compressed
states, respectively.
[0047] FIG. 19A is a vertical sectional view of device 1500 through
line 19A-19A of FIG. 18A.
[0048] FIG. 19B is a vertical sectional view of device 1500 through
line 19B-19B of FIG. 18B.
[0049] FIGS. 20A-D illustrate a face mask that includes a bi-stable
cone such that the mask can be reversibly transformed from a first
configuration for adults to a second configuration for pediatric
patients, according to one embodiment of the invention.
[0050] FIGS. 21A-C illustrate a face mask with a tear-away seam
such that the mask can be transformed from a first configuration
for adults to a second configuration for pediatric patients,
according to one embodiment of the invention.
[0051] FIGS. 22A-C illustrate an embodiment of a face mask that is
shaped and configured to create a sealing surface extending from
cephalad at the base of the nose near the alar sidewalls to
caudally under the mandible as shown.
[0052] FIGS. 23A-C are perspective views an embodiment of a
"bow-tie" shaped ventilation device in expanded and progressively
compressed states.
[0053] FIGS. 24A-B are cut-away views of the device of FIGS.
23A-C.
[0054] FIG. 25A is an exploded perspective view of a ventilation
device with supplemental side panels, according to one embodiment
of the invention.
[0055] FIG. 25B illustrates the device shown in FIG. 25A with a
skin layer.
[0056] FIG. 25C illustrates a ventilator with panels surrounding an
Ambu bag reservoir, according to one embodiment of the
invention.
[0057] FIGS. 26A-C illustrate a partial perspective view of a
ventilation device with supplemental side panels, in expanded and
progressively compressed states, according to one embodiment of the
invention.
[0058] FIGS. 27A-C illustrate a partial perspective view of a
mechanical ventilator without supplemental side panels, in expanded
and progressively compressed states.
[0059] FIG. 28A is a perspective view of a mechanical ventilator
with elongate folds, according to one embodiment of the
invention.
[0060] FIG. 28B is an end view of the device of FIG. 28A, in an
expanded configuration.
[0061] FIG. 28C is an end view of the device of FIG. 28A, in an
compressed configuration.
[0062] FIG. 29A illustrates axes in which certain panels of a
ventilation device are capable of rotating around.
[0063] FIG. 30A illustrates a ventilation device with a PEEP port
having a control, according to one embodiment of the invention.
[0064] FIG. 30B illustrates a view of the pressure port of FIG. 30A
with the control at a first pressure setting.
[0065] FIG. 30C illustrates a view of the pressure port of FIG. 30A
with the control at a second pressure setting.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0066] Although the following detailed description contains many
specifics for the purposes of illustration, one of ordinary skill
in the art will readily appreciate that many variations and
alterations to the following exemplary details are within the scope
of the invention. Accordingly, the following preferred embodiments
of the invention are set forth without any loss of generality to,
and without imposing limitations upon, the claimed invention.
[0067] A three-dimensional view of one example of the ventilation
or resuscitation device 100 is shown in FIG. 1. In general, three
parts can be distinguished: a reservoir that includes a body 110,
an input mechanism 120 to allow input of e.g., air, oxygen,
oxygen-enriched air, fluid, fluid mixture, gas, gas mixtures or any
combination or derivative thereof in body 110, and an output
mechanism 130 to output and deliver some or all of the inputted
content from body 110 to an individual via connector 132. Body 110
distinguishes a plurality of movable walls (also referred to as
panels herein). Movable walls can be, in some embodiments, panels
that are movable with respect to each other. In some embodiments,
the panels are rigid or substantially rigid. Design of body 110
with rigid panels encompasses a sealed volume that can contain
e.g., air, oxygen or oxygen-enriched air. Another aspect of the
invention is to be able to hold the body of the device with one
hand and to compress the body with that one hand. In one
embodiment, as will be clear from reading the description,
disclosed is a device with a body having rigid panels whereby the
body is characterized as having a displacement in a direction of a
hand displacement and at least one other direction other than that
particular hand displacement.
[0068] In the particular example of FIG. 1 body 110 distinguishes a
plurality of panels; e.g., panels forming the top, panels forming
the bottom, and panels for each side. More particularly, the
following (main) panels can be distinguished, i.e. panels 140A,
140B, 140D, 140E, 140F, 140G and 140H, which are all visible in
FIG. 1; panels 140D, 140E, 140F, 140G, 140H, 140D', 140E', 140F',
140G', 140H', which are all visible in FIG. 2; panels 140A, 140B,
140C, 140D, 140E, 140F, 140G, 140H, 140D'', 140E'', 140F'', 140G''
and 140H'', which are all visible in FIG. 3; and panels 140C and
140C', which are all visible in FIG. 4. Panels blocked from the
views in FIGS. 1-4, are 140A', 140B', 140D''', 140E''', 140F''',
140G''', 140H'''. The relative positions and orientations of the
panels blocked in the figures is readily appreciated by a person of
ordinary skill in the art to which this invention pertains.
[0069] The movable parts or structures, indicated by 150 in FIGS.
1, 2 and 4 could be living joints/hinges, snaps, joints, fabricated
flexures, heat-shrinked joints or flexures, welded joints, simple
mechanical hinges, pinned hinges, flexible hinges, snap-fit
assembly hinges, or the like. The type of movable structure 150
depends on the type of manufacturing that is used to create the
rigid panels and body. Examples of different types of manufacturing
of the panels, movable structures and body are e.g., blow molding,
heat sealing, overmolding, the mechanical assembly of a rigid
paneled chassis with a flexible bladder or skin to form the body,
coining to form living hinges, assembly using gaskets as seals in
hinges, injection molding, ultrasonic welding, radio frequency
welding, dielectric welding, high frequency welding, dipping,
extrusion, spray coating, brush on, assembly of adhesive backed
sheets of various materials, and/or any type of manufacturing that
results in a body with rigid panels that are movable with respect
to each other. In some embodiments, the panels of the body 110 and
the movable structures 150 are co-molded together to allow for the
use of a very compliant low durometer material for the panels of
the device 100 to advantageously provide a soft grip for an
operator of the device, while still utilizing a very durable, rigid
material for the movable structures 150. A person of ordinary skill
in the art to which this invention pertains would readily
appreciate the different types of manufacturing that can be used to
make body 110, which are known techniques in the mechanical and
design engineering art. Input mechanism 120 and output mechanism
130 could be manufactured and integrated along with the
manufacturing process of body 110 or later assembled to body 110.
The types of materials that can be used for the rigid panels, input
mechanism 120, output mechanism 130 and other structures of the
device are, for example, polymers, plastic, polyethylene,
polycarbonate, high impact polystyrene, K-resin, ABS, PVC, acetal,
polypropylene, silicone, thermoplastic elastomers, thermoplastic
rubbers, latex, fabrics, cardboard, nylon webbing, or the like.
[0070] The volume delivery is preferably consistent from
compression to compression, as well as consistent with respect to a
disclosed volume setting on the volume adjuster. In a preferred
embodiment, the device 100 is configured to output a consistent,
reproducible volume for a given speed of compression of the device
100 by an operator and for a given airway resistance. In some
embodiments, the actual volume delivered differs by no more than
about 50 cc, 40 cc, 30 cc, 25 cc, 20 cc, 15 cc, 10 cc, 5 cc, or
less than the volume selected on the volume adjuster to be
delivered. In some embodiments, the device 100 can be configured
such that the actual volume delivered per compression can be
consistently reproducible within no more than about 50 cc, 40 cc,
30 cc, 25 cc, 20 cc, 15 cc, 10 cc, 5 cc, or less from a preset
delivered value (e.g., from volume adjuster) compression to
compression.
[0071] The device 100 is also preferably configured to preferably
deliver a consistent volume regardless of the manner or speed in
which the device is compressed. In some embodiments, the device 100
is configured to deliver a consistent volume when compressed using
a mechanical force, for example, one hand, two hands, one foot, two
feet, a knee, in between two knees, an elbow, or a forearm (while
bracing the device against a thigh or other surface, e.g., a table
or the patient's head). The device 100 is also preferably
configured such that applying a force to any one or more of the
walls of the body 110 will result in delivery of a consistent
volume, and will also result in the device achieving a fully
compressed state. The fully compressed state of the device 100
preferably has a volume of no more than about 40%, 35%, 30%, 25%,
20%, 15%, 10% or less of the uncompressed state of the device
100.
[0072] Body 110 has an uncompressed state where the panels are
positioned to create a volume that can be filled with e.g., air,
oxygen or oxygen-enriched air. From the uncompressed state, body
110 can change to a compressed state where the panels are moved
with respect to each other to decrease the volume with respect to
the volume in the uncompressed state. In other words, moving the
rigid panels with respect to each other from the uncompressed state
to the compressed state, air, oxygen or oxygen-enriched air is
outputted via output mechanism 130. The uncompressed state could be
at full expansion (i.e. maximum volume) or any intermediate state
(See also size adjuster (volume) description). Restoring the volume
allows entry of new air, oxygen or oxygen-enriched air into the
volume via input mechanism 120.
[0073] In some embodiments, the device 100 also includes an air
filter. The air filter is preferably integrated with the device,
for example, via an adapter operably connected to the input
mechanism 120. The air filter can advantageously remove dust,
pollen, mold, bacteria, viruses, and other airborne particles from
an air source prior to entry into body 110 of the device 100. In
some embodiments, the air filter is configured to meet or exceed
HEPA (high efficiency particulate air) filter standards.
[0074] Body 110 has a height H, width W and length L (see FIGS.
1-4). In general, the state changes of body 110 could be
characterized by the height H of body 110 being larger in the
uncompressed state compared to the compressed state. The height
changes cause changes in width W and length L, which are smaller in
the uncompressed state compared to the compressed state. The width
and length changes are a function of the height changes and the
geometry of panels as a person of ordinary skill would readily
appreciate. It is further noted that the body could be
characterized by having at least two of the panels capable of
rotating around substantially orthogonal axes with respect to each
other; consider e.g., panels 140F and 140C which are both involved
in the height changes, but given their orientation, 140F is further
related to the width changes, and 140C is further related to the
length changes. In summary, the body is characterized as having a
displacement in a direction of a "hand displacement (e.g., height
of body) and at least two other directions (e.g., width and length
of body) other than the particular hand displacement (e.g., height
of body).
[0075] FIGS. 1A-1C are schematic diagrams illustrating the
interaction of panels 140 where movable structures 150 are either
present or absent on a ventilation device 100. FIG. 1A shows that
adjacent movable walls (e.g., 140F and 140F'; 140F'' and 140F'''
are not shown) can be operably connected by movable structures 150,
which can be snap-fit assembly hinges, according to one embodiment
of the invention. Dotted line 151 represents an axis, defined by
the border between two adjacent walls 140F, 140F' as shown, around
which walls 140F and 140F' can rotate with respect to hinge 150.
The movable structures 150 are preferably configured such that a
movable structure 150 operably connected to two adjacent walls can
rotate substantially uniformly around the axis 151 when the
reservoir 110 of device 100 moves from an uncompressed to a
compressed state, and vice versa. In this way, the hinges 150
operably connected to adjacent walls, e.g., 140F, 140F'
advantageously provide for generally uniform collapse and expansion
of the device 100 substantially preventing non-uniform bending or
sliding of the walls 140F, 140F' in axes other than axis 151 as
shown; preventing non-uniform bending of walls 140A and 140C as
shown, and resulting in consistent volume delivery to a patient.
This is in contrast to a ventilation device that collapses
non-uniformly due to the absence of stabilizing movable structures
(such as hinges 150) between, for example, unhinged folds of
inflatable bladders, disclosed, for example in U.S. Pat. No.
4,898,167 to Pierce et al., which is hereby incorporated by
reference in its entirety. The absence of stabilizing movable
structures (such as hinges 150) can result in rotation and/or
flexing of the folds in multiple axes, and consequently,
inconsistent volume delivery. The side view schematics shown in
FIGS. 1B-1C illustrate how device 100 would non-uniformly rotate
without hinges 150 operably connected to panels 140F and 140F'.
FIG. 1B is a side view schematic of the device of FIG. 1A depicting
panels 140A, 140C, 140F, 140F' without hinges 150. FIG. 1C is of
the same side view as FIG. 1B after compression of the device. As
shown, the absence of movable structures between, for example,
panels 140F and 140F' can allow panels to rotate non-uniformly in
multiple axes other than 151. End panel 140A, for example, could
rotate non-uniformly with respect to panel 140C. As noted above,
this can undesirably lead to inconsistent volume delivery.
[0076] The body could also have a higher or a smaller number of
panels than body 110, as a person of average skill in the art to
which this invention pertains would appreciate. For example, the
panels could be assembled radially around central top and bottom
panels and more panels can be added, for example, 140F can be
broken up into two or more panels. An example of reducing panel
numbers could be achieved by reducing 140A, 140B and 140C to only
two panels. In the latter example the body would have height and
width or length changes. In summary, such bodies could be
characterized as having a displacement in a direction of a hand
displacement (e.g., the height of body) and at least one other
direction (e.g., the width or length of body) other than the
particular hand displacement (e.g., the height of body).
[0077] As mentioned above, one of the key objectives of the
invention is to be able to hold the device with one hand and to be
able to compress the body with that one hand. To meet the objective
the height and width changes in uncompressed and compressed state
are therefore constrained since they would need to fit: (i) the
hand of a user and (ii) the grasping (or squeezing) range of motion
of the user.
[0078] Furthermore, the thumb and one or more fingers are desirably
positioned on body 110 to create a mechanical advantage (i.e. a
large moment arm with respect to the point of rotation) when
compressing the body. Such a mechanical advantage meets another
objective of the invention, which is to reduce fatigue of the hand
muscles and potentially also the arm muscles.
[0079] FIG. 5 shows hand 500 with thumb 502, one or more fingers
504 and web of the hand 506 between which body 110 is typically
held. Given a variety of hand sizes (e.g. male, female, large and
small) in mind one could determine a reasonable range of motion and
a comfortable fit to the user's hand that constrains the height and
width dimensions of body no when moving between the uncompressed
state and a compressed state. The maximum height of the fully
expanded device, in some embodiments is no more than about 100 mm,
preferably between about 45-70 mm with a side panel (e.g., panels
other than 140B and 140B' in some embodiments) width of no more
than about 60 mm, preferably between about 30-50 mm. These
dimensions, for example, advantageously allow the device to be
compressed in one hand comfortably by a wide range of both male and
female operators of the device 100. In some embodiments, the height
and width (displacement) changes of a single panel axially could be
no more than about 85 mm, preferably no more than about 20-25 mm
and more preferably no more than about 10-15 mm. The height changes
would correspond to a hand displacement 520 in FIG. 5 and the width
changes would correspond to a hand displacement 510 in FIG. 5. A
person of average skill in the art to which this invention pertains
would readily appreciate that the geometry (dimensions and relative
angles) of the panels could be varied to meet the desired height
and width (displacement) changes as well as the desired deliverable
tidal volume.
[0080] The length changes of a single panel axially could also be
no more than about 85 mm but is, in some embodiments, not
constrained by hand dimensions, but will be a variable in
determining the change in volume. The change in enclosed volume of
the device (in other words, the deliverable or expressed volume of
a device) is typically no more than about 1400 cc in some
embodiments. In other embodiments, the deliverable volume ranges
from about 250 to 1200 cc, which covers tidal volume ranges for
children and adults. When the device is used for infant or child
purposes the volume changes are smaller and preferably are no more
than about 500 cc. The maximum deliverable volume of a device can,
in some embodiments, be adjusted in increments of at least about 25
cc, 50 cc, 75 cc, 100 cc, 125 cc, 150 cc, 200 cc, or more. The
ability to configure the device to set an adjustable maximum
deliverable tidal volume advantageously provides an increased level
of safety and reduces the risk of excess volume delivery, and thus
complications of volutrauma such as pneumothorax.
[0081] FIG. 6 shows an exploded view of an embodiment of a
ventilation device. In addition to the elements discussed above,
the device further includes a main shaft 610 connected to output
mechanism 130 and positioned inside body 110. Main shaft 610 has
narrow (cylindrical) end 612 and a slot 614. The device further has
a receiving shaft 620 connected (or could be a single part) to
input mechanism 630 and also positioned inside body 110. Receiving
shaft 620 has an opening (not visible in figure) sized to allow
travel of main shaft 610 along the length of receiving shaft 620.
It further has a slot 622 preferably of equal size as slot 614;
slots 614 and 622 should also be aligned with each other as will be
understood when discussing volume recovery from compressed state to
uncompressed state with respect to FIG. 8. Opening 630 could be
sized such that element 660 could be mechanically assembled by
ultrasonic welding, snap fit, press fit, adhesive or any other
known techniques in the mechanical and design engineering art.
Element 660 allows fitting and attachment of air/oxygen input
devices. A flutter valve 640 is fitted to the front opening of
element 660 allowing e.g. air travel into receiving shaft 620
through opening 650 and then into body 110. Element 660 further
houses a size adjuster (also referred to as volume adjuster).
[0082] In general, the size adjuster of the device adjusts the
length changes, width changes and/or height changes. The size
adjuster serves the purpose of easily adjusting the deliverable
volume so that the user can rely of a fairly constant volume of
deliverable e.g. air, oxygen or oxygen-enriched air. Adjusting the
deliverable volume is important to compensate for factors such as
physical condition, body size, age, sex, etc.
[0083] In a preferred embodiment, size adjuster is integrated with
input mechanism 120, in particular with element 660, and adjusts
the travel length of body 110. The size adjuster distinguishes an
adjustment knob 160 placed on top of element 660 and conveniently
accessible to a user. The adjustment knob 160 is connected to an
adjustment dial 162, which in this example is positioned inside
element 660; the connection could e.g. be through either valve 670
or 680.
[0084] FIG. 7 shows adjustment dial 162 with a number of slots
710,712,714,716 and 718. These slots are sized to fit narrow
(cylindrical) end 612 of main shaft 610 that is able to travel all
the way through the opening of receiving shaft 620 (as well as
through flutter valve 640; not shown in figure) when moving between
uncompressed and compressed states. By changing adjustment knob
160, adjustment dial 162 is rotated around pivot 720 to a new slot
position; this is typically done when the body is in compressed
state. It is noted that size adjuster changes the dimension of the
uncompressed state or volume.
[0085] Slots restrict the travel distance of main shaft 610 and
therewith control the deliverable volume to an individual. Slot
sizes could be up to no more than about 170 mm to allow changes in
length, and preferably are no more than about 25 mm. The number of
slots and the sizes of the slots are selected to cover a reasonable
range of deliverable tidal volumes as a person of ordinary skill in
the art will appreciate.
[0086] In the example of FIG. 7, the size (length) (volume)
adjuster is placed outside body 110. A person of average skill in
the art to which this invention pertains would appreciate that the
size adjuster can also be positioned inside the body or intrinsic
to the design of the body. Furthermore, the size adjuster could
also be added for width or height control or any combination of
height, length or width, or any other direction in a similar
fashion as shown in FIG. 7.
[0087] FIG. 7A illustrates an exploded perspective cut-away view of
another adjustment dial 163, according to one embodiment of the
invention. Shown are the variable-length slots 750, 752, 754, 756,
758 that are configured to fit the narrow end 1612 of a slider-type
volume adjuster, such as 1610 of FIG. 16 (shown in FIG. 7A not
necessarily to scale). Narrow end 1612 can be rectangular, although
other shapes can also be used as known in the art. Turning the
adjustment dial 162 in an appropriate direction will thus change
the travel distance of main shaft of slider 1610 within the body
110 of device 100, and thus control the tidal volume delivered to
an individual as noted above. In some embodiments, the slots 750,
752, 754, 756, 758 are configured such that turning the adjustment
dial 163 to allow end 1612 of slider 1610 to engage an adjacent
slot will produce a change in deliverable tidal volume of at least
about 25 cc, 50 cc, 75 cc, 100 cc, 125 cc, 150 cc, 200 cc, or more.
In some embodiments, a label (not shown) is present on or near
adjustment dial 163 to assist an operator by indicating, for
example, the numerical tidal volume correlating to the appropriate
slot, and/or whether the slot setting is appropriate for adults,
children, or infants. FIG. 7B is a horizontal sectional view of an
adjustment dial 163 with slots 750, 750', 752, 752', 754, 754',
756, 756', 758, 758' in which slots spaced 180 degrees apart, such
as slots 750, 750' have the same or substantially the same length
to accommodate end 1612 of slider 1610.
[0088] Instead of a size adjuster with slots, one could design and
integrate different types of mechanisms, which are all within the
scope of the present invention. Examples of such variations are
e.g. an adjustable threaded stop for the main shaft, an element
with chambers whereby each chamber has grooves or each chamber has
different depths, a slotted tube with different positions of the
slots to set travel constraints to the main shaft, deflecting stops
that deflect when adjusted in an incorrect or uncompressed state, a
rack and pinion system with stops, ratcheting band (adjustable
zip-tie), adjustable cam, a rotating dial of spring loaded stops
that deflect when adjusted in an incorrect or uncompressed state,
or any type of engineering mechanism that constrains the travel of
the main shaft to control the volume output.
[0089] FIG. 8 shows an example of a volume restoring mechanism to
restore the volume from a compressed state back to the uncompressed
state. This could be accomplished by main shaft 610 traveling
inside receiving shaft 620 whereby (part of) slots 614 and 622
travel inline with each other. One site of slot 614 is connected to
an opposite site of slot 622 by element 810, which is e.g. an
extension spring, plastic or rubber. When we change from
uncompressed state to compressed state, force is built-up in
element 810. This force is then used to restore the body back to
the uncompressed state when the user releases the compression force
applied to body 110. As a person of average skill in the art to
which this invention pertains would appreciate, the volume
restoring mechanism could also be outside body 110 or intrinsic to
body 110 (e.g. one could have the restoring force as an intrinsic
property of the movable joints 150). Other alternatives are a leaf
spring mechanism inside body 110 that builds up force when
compressed or an extension spring/mechanism placed inside body 110
but not integrated with the two shafts. The volume restoring
mechanism could be adjusted using similar techniques as discussed
for the size (volume) adjuster or it could be left to one
setting.
[0090] In an alternate embodiment, the device includes a frequency
adjuster to set and control the time to: (i) restore the volume
from a compressed state back to the uncompressed state, and/or (ii)
compress the volume from uncompressed state to a compressed state.
The volume restoring mechanism as discussed above could be used as
a frequency adjuster/controller. However, in this scenario, the
frequency control is then still in hand of the user and not
constrained by the device. Control over frequency is desired to
enforce consistency in tidal volume rate. Therefore in another
embodiment a frequency adjuster is added in a similar fashion as
the size adjuster.
[0091] A frequency control knob could be placed at the opposite
site of element 660 and implemented to adjust the frequency by e.g.
a rack and pinion mechanism in combination with the main shaft to
set the dampening of travel of the main shaft, a rack and pinion
mechanism coupled with rotationally resistant gears, a polymer
escapement mechanism, a friction brake, a rotationally resistant
ratchet wheel, or a track to deflect the travel of the main shaft.
All such mechanisms, which are known in the mechanical and design
engineering art, can be adjusted via a frequency control knob to
change the dampening of the travel of the main shaft, whereby an
increase in dampening would result in a decrease in frequency.
Similarly to the size adjuster mechanism, the frequency adjuster
could also be inside the body, outside the body or intrinsic to
body.
[0092] FIG. 9 shows an example of an embodiment of a frequency
control mechanism 900 that is accomplished by a ratchet mechanism
910 placed on frequency control knob 920. Frequency control knob
920 can extend up from an identical knob to volume control knob
610, inverted and assembled to the bottom of the element 660. A
ratchet wheel 930 can be assembled to frequency control knob 920 by
e.g. a snap fit, a fastener or any other means. Frequency control
knob 920 can be rotated with ratchet wheel 930 in line with the
main rod's travel or outside of its travel. The ratchet wheel's
rotation can be dampened by multiple methods such as e.g. a
friction insert, a roll pin, a coil or a watch spring, a high
friction disc, or the like. There could be a variety of ratchet
wheels along the circumference of frequency control knob 920 to
adjust the resistance to main rod 610 depending on the rotation
direction of frequency control knob 920. In some embodiments, the
frequency control mechanism 900 can be configured such that the
device can deliver no more than about 40 breaths per minute. In
some embodiments, frequency control mechanism 900 can be configured
to adjust frequency in increments of no more than about 10, 8, 6,
5, 4, 3, 2, or 1 breaths per minute.
[0093] A visual feedback mechanism could be added to provide the
user with visual feedback (colors, markings, symbols, or the like)
on the adjustments to size, travel of the main shaft, or the
frequency. FIG. 10 shows an example of a visual feedback mechanism
for the size (volume) adjustments. Main shaft 610 could travel
across a ruler 1010 designed to indicate e.g. minimum min, average
avg, and maximum max deliverable tidal volume (expressed volume).
The relative position of narrow end 612 of main shaft 610 to
markings 1012 could further assist in fine-tuning the desired
volume. The visual feedback mechanism could be placed inside a body
whereby the body has a transparent part allowing a user to
visualize the visual feedback mechanism. A similar feedback
mechanism could be applied for the frequency.
[0094] One could further add an audible feedback mechanism (beeps,
timers, commands, warnings, or the like) that provides feedback
over the compression speed, frequency, tidal volume, setting of the
size (volume) adjuster or setting of the frequency control
adjuster. Another example is to have a click mechanism associated
with the travel of the shaft(s) and/or changes in volume. The
clicking sounds could also be used as a tactile feedback; e.g. the
clicks can be felt through the hand. In some embodiments, the
audible feedback mechanism is a pop-off valve that can be operably
connected to output mechanism 130. The pop-off valve can be
configured to provide an audible cue when a certain threshold
airway resistance is reached, thus alerting the operator of the
device of a potential airway problem such as a foreign body,
pneumothorax, or inadvertent gastric intubation.
[0095] In still another embodiment, one could add tactile feedback
areas 1130 on one or more of panels such as panel 140B as shown in
FIG. 11; 1110 is a top view and 1120 is a side view. Tactile
feedback areas 1130 are sized and positioned to fit a thumb of a
hand or one or more fingers (e.g., on panel 140B') of the hand.
These areas are made of a flexible material that is responsive to
thumb or finger pressure as well as pressure from e.g. the
air/oxygen inside the body. This will provide the user additional
feedback on the compression force and lung resistance. Deflection
1132 of flexible material 1130 with respect to the rigid panel 140B
illustrates the deflection caused by e.g. a finger during
compression.
[0096] FIG. 12 shows an example of stacking or nesting multiple
devices 100 on top of each other. Stacking or nesting would be
beneficial where space is limited, e.g. in an ambulance, and where
multiple devices might be required. In one example the design and
geometry of the inlet mechanism, body and/or output mechanism
allows them to nest with one another. For example, the top of the
output mechanism could nest into the bottom of another output
mechanism (a similar nesting could be established for the input
mechanism). Besides fitting the devices together, the device could
also have features, e.g. ribs, indentations, Velcro,
snap-mechanism, or the like, that prevent side-to-side movement. In
one embodiment, the body 110 of the device 100 has dimensions of
about 200-235 mm.times.240-290 mm.times.50-65 mm in a compacted
configuration. In some embodiments, three devices can fit in a
shelf height of no more than about 250 mm, 240 mm, 230 mm, 220 mm,
210 mm, 200 mm, 190 mm, 180 mm, 170 mm, 160 mm, 150 mm, or
less.
[0097] In some embodiments, device 100 can maintain its maximum
fully uncompressed volume, as well as deliver a consistent tidal
(delivered) volume after being stored for a prolonged period of
time. Being able to maintain this capability can be highly
advantageous over current bag-type ventilators, for example, which
have a relatively short shelf-life due to degradation of the bag
material over time. Furthermore, use of a compression spring as a
volume restoring mechanism, for example, can be advantageous as
relaxation of the spring over time should not significantly affect
the deliverable volume of the device. Volume delivery effected by
creep or stress relaxation of components can be minimized by using
an appropriate material as known in the art, such as a polymer. In
some embodiments, a device 100 can be stored for at least about 1
year, 2 years, 3 years, 4 years, 5 years, 7 years, 10 years, 15
years, 20 years, 25 years, 30 years, or more while maintaining the
capability to compress to a volume of less than about 35%, 30%,
25%, 20%, 15%, 10%, or less of the fully uncompressed volume of the
device, as well as expand to at least about 90%, 95%, 97%, 98%, 99%
or more of the fully uncompressed volume of the device prior to
storage.
[0098] FIGS. 13A-D illustrate embodiments of visual airflow
indicators that can be used with a volume-adjustable manual
ventilation device, according to some embodiments of the invention.
The visual airflow indicator provides a visual cue that air is
flowing into the device 100 for delivery to a patient's airway. The
visual airflow indicator can be operably connected to the input
mechanism 120 of the device 100. The visual airflow indicator can
be, in some embodiments, an expandable reservoir as part of an
inflow line 1300, for example, an oxygen line or reservoir tube,
and can be integrally connected to input mechanism 120 itself. The
reservoir 1300 can be made of any appropriate material known in the
art, such as, for example, a polymer, plastic, or rubber. FIGS.
13A-B illustrate one embodiment of a visual airflow indicator 1302,
1302' that is a circumferentially-expandable bag movable from a
first deflated configuration 1302 in the absence of airflow into
the input mechanism 120 (FIG. 13A) to a second inflated
configuration 1302' when air is flowing into the input mechanism
120 (FIG. 13B). FIGS. 13C-D illustrate another embodiment of a
visual airflow indicator 1300 that includes expandable elements
1304 that can expand radially outwardly to configuration 1304' as
shown (FIG. 13D) when air is flowing into the input mechanism
120.
[0099] FIG. 14 illustrates an inflow line 1400 (e.g., an oxygen
line or a reservoir tube) that may be operably connected to input
mechanism 120 of device 100 and configured to allow for measuring
an aspect of the patient, such as the patient's height. The
patient's height, combined with knowledge of the patient's weight,
or an estimation of their ideal body weight, can be used to
calculate the patient's body mass index and select an appropriate
volume delivery setting using the volume adjuster of the device
100. In the embodiment shown, inflow line 1400 includes markings
1402 that can define, for example, length measurements in inches or
centimeters. In other embodiments, inflow line 1400 includes
color-coded marking sections that correspond to colors on volume
adjuster, such as adjustment dial 162. Other markings or coding
systems on various elements of the device configured to measure an
aspect of the patient to determine an appropriate volume (and/or
frequency setting, to set an appropriate minute ventilation) can
also be used, as will be appreciated by one of ordinary skill in
the art.
[0100] FIG. 15 is a perspective view of a ventilation device 1500
similar to the device 100 shown and described in connection with
FIGS. 1-4. Body 1510 of device 1500 is encompassed by a covering
layer 1501 (as better understood from FIG. 16) over panels 1540A,
1540B, 1540C, 1540F, 1540F'' and movable structures 150 of the
device 1500 (panels and movable structures are more clearly seen in
FIG. 16 below), and serves to provide an air-tight seal over the
body 1510 of the device 1500. Covering layer 1501 (also referred to
as the skin) may be made of plastic, rubber, polymer, thermoplastic
elastomer, or other suitable material as would be appreciated by
one of ordinary skill in the art. Covering layer 1501 may be slid
on, adhered, co-molded, radio frequency welded, mechanically locked
using rivets or screws, or otherwise attached to the body 1510 as
known in the art. Covering layer 1501 can also advantageously act
as a volume restoring mechanism if made of a resilient material,
such as an elastomer.
[0101] Device 1500 also includes an input mechanism 1520 and output
mechanism 1530 to output and deliver some or all of inputted
content from body 1510 via patient connector 1533 as described in
connection with FIG. 1 above, as well as adjustment dial 163. Also
shown is positive end-expiratory pressure connector 1532 of output
mechanism 1530 ("PEEP" connector). In contrast to the device 100
shown in FIGS. 1-4, device 1500 does not include panels 140D,
140D', 140D'', 140D''', 140E, 140E', 140E'', 140E''', 140G, 140G',
140G'', 140G''', 140H, 140H', 140H'', and 140H''' of device
100.
[0102] FIG. 16 is an exploded view of the device 1500 illustrated
in FIG. 15. Body 1510 of device 1500 includes first portion 1606
and second portion 1608. First portion includes a plurality of
panels 1540A, 1540B, 1540C, 1540F, 1540F'' operably connected by
movable structures 150 that are preferably snap-fit hinges in some
embodiments, as described in connection with FIG. 1 above. First
1606 and second portions 1608 also can include apertures 1611 as
shown configured to receive a screw, nail, bolt, snap-on nub, or
the like to connect first 1606 and second portions 1608 together
and/or to the covering layer 1501. Also illustrated is output
mechanism 1530 and patient connector 1533 as previously described,
and attached to body 1510 via element 1531 which can be a seal,
gasket, or the like. Input mechanism 1520 and adjustment dial 163
can also be as previously described, and can be connected to body
1510 via elements 1521 and 1561, respectively. Elements 1521, 1561
may be seals, gaskets, and the like similar to element 1531.
Adjustment dial 163 shown rotates in a plane perpendicular to main
slider 1610 with narrowed end 1612, although it can also rotate
parallel, or in other orientations to main slider 1610 as well in
other embodiments. As described in connection with FIG. 7 above,
other volume adjusters known in the art may be used as well.
[0103] Second portion 1608 of body 1510 includes panels 1540A',
1540B', 1540C', 1540F', and 1540F''' also connected by movable
structures 150. Also illustrated is main slider 1610 which can
include elements of main shaft 610 and receiving shaft 620 as
described in connection with volume adjuster and volume restoring
mechanism and FIGS. 7-8 above. Main slider 1610 movably resides
within main slider housing 1602. Element 810 shown is a spring,
preferably a compression spring as part of volume restoring
mechanism as described in connection with FIG. 8 above.
[0104] Also shown in FIG. 16 are side sliders 1600 connected to
panels 1540F, 1540F' and panels 1540F'', 1540F''' by movable
structures 150, e.g., snap-fit hinges. Side sliders 1600 movably
reside within side slider housing 1604, and structurally stabilize
the device 1500 during actuation, as better illustrated in FIGS.
17-18 below.
[0105] FIG. 17A is a side view of device 1500 in an uncompressed
state with covering layer 1501 removed for clarity. Shown are input
mechanism 1520, output mechanism 1530 with patient connector 1533
and PEEP connector 1532, and panels 1540A, 1540A', 1540C, 1540C',
1540F and 1540F' operably connected to adjacent panels by hinges
150 as previously described. FIG. 17B shows the device of FIG. 17A
(with covering layer 1501) in a compressed state.
[0106] FIGS. 18A-B are top horizontal sectional views of device
1500 in uncompressed and compressed states, respectively. As shown
(and perhaps better seen in FIGS. 19A-B), side sliders 1600 move
medially toward each other as the device 1500 moves from the
uncompressed to the compressed state, while narrow end 1612 within
main slider 1610 moves into slot 750 (and slot 750', not shown) of
adjustment dial 163. Exertion of a compressive force (e.g., by
manual pressure on one or more panels) on device 1500 will result
in a buildup of force within spring 810 (which is preferably a
compression spring in this embodiment) and result in restoring the
body 1510 back to an uncompressed state when the compressive force
is released.
[0107] FIG. 19A is a vertical sectional view of device 1500 through
line 19A-19A of FIG. 18A. FIG. 19B is a vertical sectional view of
device 1500 through line 19B-19B of FIG. 18B. Shown are panels
1540A, 1540A', 1540B, 1540B', 1540C and 1540C' operably connected
to adjacent panels by hinges 150 as previously described. As noted
above, as device 1500 moves from the uncompressed (FIG. 19A) to the
compressed (FIG. 19B) state, narrow end 1612 of main slider 1610
will move into slot 750 (and slot 750', not shown) of adjustment
dial 163. As will be readily appreciated by one of ordinary skill
in the art and described in connection with FIG. 7A above, tidal
volume delivered by device 1500 can be readily adjusted by
actuating adjustment dial 163 in an appropriate direction, thus
changing to a different slot with a different length and distance
traveled by main shaft 610 from the uncompressed to the compressed
state.
[0108] FIGS. 20A-D illustrate a face mask 2000 that can be used
with a ventilation device, according to one embodiment of the
invention. A single face mask can advantageously be adapted for
both adult and pediatric uses, obviating the need for two separate
masks. As shown in FIG. 20A, face mask 2000 includes an outer
portion 2004 and an inner portion 2002. The inner portion 2002 is
most preferably a bi-stable cone configured to move from a first
stable position 2002 to a second stable position 2002'. In doing
so, the bi-stable cone 2002 is displaced vertically, creating
linear movement. In a preferred embodiment, the first stable
position 2002 will allow the mask 2000 to generally fit over an
adult airway while the second stable position 2002' will allow the
mask 2000 to generally fit over a pediatric airway. The outer
diameter 2003 of cone 2002 is preferably substantially circular,
oval, or the like, although other possible shapes for the outer
diameter 2003 can also be readily envisioned. The bi-stable cone
also has an inlet portion 2006 that may interface with, for
example, an outlet of a ventilator or an oxygen line, such as
patient port 1533.
[0109] Face mask 2000 can be transformed from an first
configuration for adult use to a second configuration for pediatric
use in the following manner. FIG. 20B illustrates a vertical
sectional schematic view of face mask 2000 positioned over an adult
patient's face. Face mask 2000 is shown operably connected at inlet
portion 2006 to connector 132 of outlet 130 of ventilation device
100. A first length 2010 of mask 2000 that spans a length over
adult patient's face is shown. To transform the mask 2000 for
pediatric use, an operator can apply pressure to bi-stable cone
2000 to move cone 2000 from first stable position 2002 (shown in
phantom) to second stable position 2002' as shown in FIG. 20C.
Next, mask 2000 is turned over as shown in FIG. 20D. Once turned
over, mask 2000 has a second length 2008 that spans a length over
pediatric patient's face as shown; second length 2008 is less than
first length 2010. One of ordinary skill in the art will readily
appreciate that the mask can also readily be transformed from the
pediatric configuration to the adult configuration by performing
the steps illustrated in reverse.
[0110] FIGS. 21A-C depict another face mask that can be used with a
ventilation device, according to one embodiment of the invention.
As shown in FIG. 21A, face mask 2100 includes outer portion 2102,
inner portion 2104, and inlet 2106. Outer portion 2102 and inner
portion 2104 are operably connected by seam 2108. Seam is
preferably made of a tear-away material configured to facilitate
tearing of inner portion 2104 from outer portion 2102. In some
embodiments, the seam 2108 has thinned walls or perforations to
facilitate tearing. In other embodiments, seam 2108 includes an
adhesive material to facilitate tearing. Other tear-away materials
known in the art can also be utilized as well. FIG. 21B depicts
mask 2100 situated on an adult patient. Face mask 2100 can be
transformed from an adult configuration 2100 to a pediatric
configuration 2100' by separating (e.g., by pulling apart) outer
portion 2102 from inner portion 2104. Pediatric configuration 2100'
and separated outer portion 2102 are shown in FIG. 21C. The masks
described in connection with FIGS. 21-22 can, for example, have a
length of no more than about 135 mm, preferably between about
115-135 mm, and a width of no more than about 115 mm, preferably
between about 100-115 mm in an adult configuration of some mask
embodiments. A pediatric configuration can, for example, have a
length of no more than about 115 mm, preferably between about
75-115 mm, and a width of no more than about 100 mm, preferably
between about 70-100 mm.
[0111] FIGS. 22A-C illustrate an embodiment of a face mask 2200
that is shaped and configured to create a sealing surface extending
generally (near dotted line 2206) from cephalad at the base of the
nose 2202 near the alar sidewalls to caudally under the mandible
2204 as shown. Conventional masks are generally configured to
create a sealing surface cephalad from the nasion to caudal on the
mandible. Application of mask 2200 can advantageously create an
improved sealing surface over conventional masks, and thus improved
ventilation of a patient, especially when combined with a jaw
thrust maneuver as known in the art. In some embodiments, the
head-tilt chin-lift maneuver, as known in the art, can be
substituted for the jaw thrust maneuver. The jaw thrust maneuver is
typically performed on a supine patient by kneeling down at the
patient's head and grasping the posterior aspects of the mandible
with the fingers of both hands (with the thumbs at the chin) and
lifting up. When the mandible is displaced forward, it pulls the
tongue forward and prevents it from occluding the entrance to the
trachea, helping to ensure a patent airway. FIGS. 22B and 22C
illustrate different schematic perspective views of mask 2200 on
the patient. A jaw thrust can be performed submandibularly by
applying a force as shown by arrow 2210.
Additional Ventilator Embodiments
[0112] FIGS. 23A-C are perspective views of a manually-operable
ventilator 2300 with a "bow-tie"-like shape, according to some
embodiments of the invention. Ventilator 2300 includes top panel
2300A, bottom panel 2300B (not shown), side panels 2300C and 2300D
(with contralateral panels 2300E and 2300F not shown), side
transition zone panels 2300G and 2300H (with contralateral panels
2300I and 2300J not shown), top transition zone panels 2300K and
2300L, and bottom transition zone panels 2300M and 2300N (not
shown). Areas 2311, 2313, 2315, 2317 may be covered by supplemental
transition zone panels as illustrated in FIGS. 26A-C or
alternatively, a covering layer of skin alone. FIG. 23A illustrates
an embodiment where the device is in a fully expanded state; FIG.
23B shows an intermediate compressed state, while FIG. 23C shows
the fully compressed state of the device.
[0113] As shown in FIGS. 23A-C, the ventilator 2300 has a first end
2304, a second end 2306, a first transition zone 2308, a second
transition zone 2310, and a central zone 2312. As shown, when
compressed, in FIGS. 23B-C the ventilator 2300 decreases in
dimension H3 (in the transition zones 2308 and 2310) from the first
end 2304 to the central zone 2312, and the second end 2306 to the
central zone 2312. The central zone 2312 has a generally constant
radial dimension H2 from end to end in the expanded position as
well as in various stages of compression in some embodiments. When
compressed, the ventilator 2300 increases radially in the
difference between dimension H1 and H2 (in the transition zone
2312) from the central panel 2300A to the outer edges of both the
first and second ends 2304 and 2306. The aforementioned decrease
and increase in radial dimension of the respective transition zones
2308 (decreasing in radial dimension from dimension H1 at end panel
2304 to dimension H2 at start of central zone 2312) and 2310
(increasing in radial dimension from dimension H2 at end of central
zone 2312 to dimension H1 at end panel 2306). This shape can be
present in the device's fully expanded configuration, and
accentuated when the device 2300 is in its compressed configuration
as in FIGS. 23B and 23C. In contrast to other embodiments, such as
FIG. 15, the central portion 2312 of device of FIG. 23B can be
"inverted" with respect to the two ends 2304, 2306, in other words,
the radial height H1 of the ends 2304, 2306 is greater than the
radial height H2 of the central portion 2312 of the device. This
"inverted" configuration could also occur in the device's fully
expanded configuration, or the device could have a generally
rectangular expanded shape with a constant radial dimension from
end panel 2304 to end panel 2306 when fully expanded. A "bow-tie"
like shape of the ventilator 2300 provides an advantageous gripping
surface for one-handed operation of the device. This shape also
helps to prevent an operator's hand from slipping off the device
2300 due to the relatively larger radial height of the first and
second ends 2304, 2306 of the device. The external surface area of
the transition zone 2308 that optionally does not include a panel
is covered only by the external skin layer. While the skin is
described in some embodiments as external (e.g., on the outside of
the panels), it will be appreciated that the skin may be also in
the same plane as the panels (such as via overmolding), or even
internal (e.g., in a plane underneath the panels). End panels 2304,
2306 of the ventilator 2300 displace within the H3 dimension while
supporting the movable panels 2300A-J. End panels 2304, 2306 can
have lengths of between about 10-100 mm, such as between about
15-75 mm, or 20-50 mm in some embodiments, a width of between about
80-110 mm and a height of between about 60-90 mm in some
embodiments.
[0114] FIGS. 24A-B are cut-away views of a ventilator 2302 similar
to that illustrated in FIGS. 23A-B, with panel 2300C removed for
clarity to show stabilizing side slider 2320 linked to movable
connectors 2322 which are in turn connected to panels 2300G and
2300H as shown. Also illustrated is adjustment dial 2321 which may
be as previously described.
[0115] FIG. 25A is an exploded schematic view of the panels 2300A-N
of the ventilator 2300 illustrated in FIGS. 23A-B above, with
additional supplemental transition zone panels 2300O-2300V (panel
2300U not shown). FIG. 25B schematically illustrates the device
2600 including panels of FIG. 25A covered by, integrated in the
same plane with, or on top of a layer 2500 (also referred to as a
skin herein) to bridge gaps in between the panels and create an
airtight reservoir. In some embodiments, the skin 2500 itself is
flexible and can function as a hinge between adjacent panels
without a separate structural hinge or other movable component to
facilitate controlled compression and expansion of the ventilator
2600. As noted previously, the skin 2500 can be formed through any
method known in the art, such as spraying, molding, mechanical
assembly, adhesion, and the like. The skin 2500 can seal onto or
overlap with the ends (not shown) of the device 2600 to provide an
airtight seal.
[0116] FIG. 25C illustrates schematically another embodiment of a
ventilator 2699 with panels as shown in FIGS. 25A-B overlying a
reservoir 2599, which may be a conventional Ambu bag, bellows, or
similar device in some embodiments. Panels may be operably
connected by movable structures (not shown) such as living hinges
and/or a skin layer as previously described. Such an embodiment can
be advantageous in providing more consistent volume delivery to the
reservoir. Ventilator 2699 can include other features as previously
described, such as volume or frequency adjusters.
[0117] FIGS. 26A-C are perspective views of a selected portion of
ventilator 2600 similar to that of FIGS. 25A-B illustrating
supplemental transition zone panels 2300O, and 2300Q as illustrated
(with contralateral panels 2300S, 2300T, 2300U and 2300V, and
ipsilateral panels 2300P and 2300R not shown). Without supplemental
transition zone panels, transition zone 2310 would have four total
panels, 2300G and 2300K (with 2300I and 2300M not shown, also seen
in, e.g., FIG. 25A). Addition of one or more transition zone 2310
panels could result in transition zone having at least about 5, 6,
7, 8, or more panels, such as eight panels (transition zone panels
2300G, 2300I, 2300K, and 2300M as well as supplemental transition
zone panels 2300O, 2300Q, 2300S, and 2300U). Ventilator 2600, in
some embodiments, can have a state of compression or expansion in
which pairs of panels (e.g., 2300K and 2300M; 2300G and 23001;
2300O and 2300V; and 2300R and 2300S) are substantially coplanar to
each other. Ventilator 2600 can have, in some embodiments, at least
2, 3, 4, 5, 6, 7, 8, or more pairs of panels that are substantially
coplanar to each other.
[0118] Supplemental transition zone panels 23000-2300V can be
triangular-shaped as illustrated, although other shapes as well as
a greater number of smaller transition zone panels are also
contemplated. For example, panel 2300O could be split into at least
two, three, four, or more panels. The presence of additional
supplemental panels 2300O-2300V in a ventilator 2302 as shown can
advantageously further decrease the variability of volume delivered
from compression to compression, as shown schematically in FIGS.
26A-C, which illustrate the configuration of selected supplemental
transition zone panels 2300O and 2300Q when compared with a
ventilator 2700 (with a non "bow-tie" like shape) without the
supplemental panels, where undesirable "ballooning" of the skin
over the area 2702 not covered by a panel or panels can occur, as
illustrated in FIGS. 27A-C, in progressively increasingly
compressed states.
[0119] In some embodiments, the skin (also referred to herein as a
covering or sealing layer of the device) covers all or
substantially all of the external surface of the device to ensure
that the volume of the device is sealed. As noted above, a skin
layer "covering" as defined herein need not necessarily be over the
panels and could be also in the same plane as, or beneath the
panels in certain embodiments. The skin also covers the external
surface of the ventilator where there is no rigid panel below the
skin (e.g., in embodiments without supplemental panels in the
transition zone of the skin, as illustrated in FIG. 26A-C). In
addition, in some embodiments, as shown in FIGS. 28A-C, the
ventilator 2800 includes a skin layer 2340 has one or more small
areas of redundant skin, also referred to herein as elongate folds
2342A, 2342B, 2342C in between at least some panels, e.g., fold
2342A between 2300K and end panel 2306; fold 2342B between end
panel 2304 and panel 2300L; and fold 2342C in between panels 2300C
and 2300D as shown that can deform, such as in a radially outward
direction, during compression of the device. The slightly slack or
flaccid skin area created by the elongate folds 2342 can
advantageously reduce strain on surrounding skin areas and thus
prevent undesirable deformation, aneurysm formation, or rupture of
the skin surrounding folds 2342 which can affect the consistency of
delivered volumes from compression to compression. In some
embodiments, an elongate skin fold 2342 may have a radial dimension
2350 (that is, maximal linear distance from the fold 2342 to the
underlying panel) of no more than about 70 mm, 60 mm, 50 mm, 40 mm,
30 mm, 20 mm, or less. In some embodiments, the surface area of the
redundant skin is no more than about 10%, 7%, 5%, 3% or less of the
entire surface area of the device. Line 28B-28B represents a
vertical cross-section through the ventilator 2800 in an expanded
position illustrated in FIG. 28B, showing folds 2342A and 2342C, as
well as fold 2342D which is contralateral to fold 2342C and not
shown in FIG. 28A. Panels 2342A, 2342C, and 2342D are also labeled
for reference. FIG. 28C illustrates the deformation of fold 2342C
as a result of compression of the ventilator 2800.
[0120] FIG. 29A is a partial perspective schematic illustrating the
geometry of axes of rotation of selected panels of a
mechanically-operable ventilator, according to some embodiments of
the invention. Shown are axes A1 and A5 that panel 2300G rotates
around. Axis A1 intersects axes A2 and A3 as shown. Axis A5
intersects axis A4. Panel 2300K rotates around axis A2, and panel
2300M (not shown) rotates around axis A3. Panels 2300C and 2300D
rotate around axis A4. Axes A1 and A5 can be orthogonal to axis A4,
as well as axes A2 and A3 as shown, or intersect at other angles.
In some embodiments, one or more panels can rotate around an axis
that intersects an axis of one or more other panels at an angle of
no more than about 90, 80, 70, 60, 50, 40, 30, 20, or 10 degrees.
In the same or other embodiments, one or more panels can rotate
around an axis that intersects an axis of one or more other panels
at an angle of at least about 90, 100, 110, 120, 130, 140, 150,
160, 170, or more degrees. One or more panels can rotate around an
axis that intersects at least 1, 2, 3, 4, 5, 6, 7, 8, or more axes
that one or more other panels rotate around.
[0121] FIG. 30A shows a Positive End Expiratory Pressure (PEEP)
valve 2400 operably connected to a port on a ventilator, according
to one embodiment of the invention. Valve 2400 can be integrally
formed with or otherwise connected to the device. FIG. 30B shows a
side view of the valve 2400. Control, which may be a knob as shown
2400A that may be configured for continuous or stepwise adjustment,
is used to select the pressure setting of the valve 2400. Control
2400A can be transparent in some embodiments so that the pressure
increments or other indicia on internal housing 2400B are visible
at all positions of the control 2400A. Control 2400A can include a
translucent portion 2400C that outlines a first selected pressure
setting. The translucent section 2400C can be a simple outline, a
window, or any other means of highlighting a pressure setting that
will be appreciated by those skilled in the art. Knob 2400A is
assembled to internal housing 2400B via a thread or other
connector. Dependent on the direction of rotation, knob 2400A
displaces in a linear direction along internal housing 2400B. An
internal detent (not shown) provides a force that must be overcome
to change the desired pressure setting. The internal detent
includes a flexible plastic arm, a spring loaded stop, or similar
mechanism. FIG. 30C shows knob 2400A after it has been rotated and
displaced to a second selected pressure setting different from that
shown in FIG. 30B.
[0122] While the present invention has been described herein with
respect to the exemplary embodiments and the best mode for
practicing the invention, it will be apparent to one of ordinary
skill in the art that many modifications, improvements and
subcombinations of the various embodiments, adaptations and
variations can be made to the invention without departing from the
spirit and scope thereof. For all of the embodiments described
above, the steps of the methods need not be performed
sequentially.
* * * * *