Note: Descriptions are shown in the official language in which they were submitted.
LUNG SIMULATOR
Technical Field
[001] The present disclosure relates to the field of medical simulators for
use in training
medical professionals, and in particular to lung simulators.
Background
[002] Manikins simulating a variety of human organs and functions exist for
training
medical professionals on patient care, treatments and use of medical
equipment. In order
to teach the use of and practice using a mechanical ventilator, necessary for
controlled
and assisted ventilation of a patient, components are required to simulate
human lungs.
In addition to practice with mechanical ventilators, lung simulators can be
used to gain
experience with mouth-to-mouth ventilation and bag ventilation.
[003] It is known in the art that an arrangement of bellows, that may be
inflated and
deflated by the air supplied through the ventilator, results in an
approximation of human
pulmonary function. Adding resistance to the system, such that inflation of
the artificial
lungs is harder, may serve to simulate lung impedance.
[004] Current reliable lung simulators that may imitate different medical
conditions, with
variable resistance and compliance, are complex and too large to completely
fit inside a
manikin. The complexity of such simulators often results in a high purchase
price and
costly maintenance due to the number of parts that may fail and require
replacement. The
size of current reliable lung systems further limits their implementation in
certain training
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facilities, as the equipment may not be easily transported to and set-up for
various
settings.
[005] Lung simulators that fit inside a manikin may face one of the following
two issues.
First, they may not be easily adaptable to different resistance and compliance
settings for
simulating different medical conditions. Second, they may not faithfully
replicate the
mechanics of a human lung, and suffer from limitations in simulating
satisfactorily a lung
response, where the user may be required to make certain important
approximations to
relate the output of the mechanical ventilator to the mechanics of an actual
lung.
Summary
[006] The present disclosure relates to a combination of a frame, a lung
bladder and a
biasing system, which may comprise one or more springs, and a compliance
bladder or
an actuator, for adequately replicating lung function and any number of
medical conditions
affecting the lungs. Embodiments comprising springs and compliance bladder
simulate
lung compliance by changing the volume of air inside the compliance bladder.
Additionally, a restrictor may be added to the tube connecting the ventilator
and the lung
bladder, such that pulmonary resistance may be simulated. The simulators
described
herein allow for the replication of human respiratory profiles with high
precision for passive
lung simulation, such that the ventilator may be used in a controlled
ventilation state.
[007] While certain embodiments are described herein as being related to human
.. patients, it is to be understood that the simulators described herein can
be adapted for
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use by veterinarians wherein the lung mechanics being simulated are those of
an animal
patient.
[008] The present disclosure also relates to a lung simulator in which the
biasing system
uses an actuator and a sensor to derive the volume of the lung bladder. The
system may
be used to simulate a respiratory condition and also to simulate both passive
(i.e.
controlled ventilation) and assisted ventilation. The simulator may switch
from simulating
a patient that requires controlled ventilation to a patient that requires
assisted ventilation
or that can autonomously breathe during a same simulation episode.
[009] A first broad aspect is a lung simulator comprising a lung bladder
connectable to a
ventilation source, a compliance bladder having an adjustable volume, a
biasing member,
at least two movable plates, and a frame supporting and interconnecting the
lung bladder,
the compliance bladder, the biasing member and the at least two movable plates
such
that in use, the biasing member and the compliance bladder exert a variable
pressure on
the lung bladder through the movable plates as the volume of the lung bladder
varies,
thereby imparting to the lung bladder a compliance similar to that of a lung
and adjustable
by controlling the adjustable volume of the compliance bladder.
[0010] In some embodiments, a first one of the two movable plates is
positioned to be in
contact with and between the lung bladder and the compliance bladder, the
frame
comprises a fixed plate, and the compliance bladder and the lung bladder are
positioned
between the fixed plate and a second one of the movable plates connected to
the biasing
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member.
[0011] In some embodiments, the frame guides the movable plates for movement
parallel
with respect to the fixed plate.
[0012] In some embodiments, the second plate is disposed between the biasing
member
and the lung bladder to apply pressure to a side of the lung bladder.
[0013] In some embodiments, the second plate is interconnected to the frame
through at
least one linear bearing.
[0014] In some embodiments, wherein the frame comprises a first compartment in
fluid
coupling with one of the movable plates, the lung bladder being confined in
the first
compartment, the first compartment being airtight.
[0015] In some embodiments, the simulator has a second compartment holding the
compliance bladder and the biasing member, wherein a tube connects the first
and
second compartments, such that a volume change in one of the first and second
compartments is reciprocated in the other of the first and second
compartments.
[0016] In some embodiments, the simulator has a cylinder connectable to the
first
compartment, such that an air volume change in one of the cylinder and the
first
compartment is reciprocated in the other of the cylinder and the first
compartment, and;
[0017] an actuator operably connectable to a piston in the cylinder, such that
a
displacement of the piston results in the air volume change.
[0018] In some embodiments, the ventilation source is a ventilator, the lung
bladder
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comprises a tube or hose connector for connecting to a ventilator tube or
hose, and when
the lung bladder is connected to the ventilation source via a restrictor, the
lung bladder
can be inflated and deflated between a positive end-expiratory pressure and a
peak
inspiratory pressure to produce a pressure-volume curve similar to that of a
lung.
[0019] In some embodiments, the simulator also has one or more additional lung
bladders
and wherein the biasing member provides a relaxed expiration force to the lung
bladder
and to the one or more additional lung bladders.
[0020] In some embodiments, the biasing member comprises one or more
additional
compliance bladders, wherein changing a volume of each of the one or more
additional
compliance bladders simulates changing the lung compliance.
[0021] In some embodiments, the simulator also has a first tube and a first
restrictor
connectable to the lung bladder, and one or more additional tubes comprising
one or
more additional restrictors connectable to the one or more additional lung
bladders. The
first tube and the one or more additional tubes merge and are connectable to
the
ventilation source such that the first restrictor restricts air flow supplied
to the lung bladder
and the one or more additional restrictors restrict air flow supplied to the
one or more
additional lung bladders.
[0022] In some embodiments, at least one of the restrictor and the one or more
additional
restrictors is an actuator-controlled, variable valve.
[0023] In some embodiments, at least one of the restrictor and the one or more
additional
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restrictors is an electrically controllable restrictor, and further comprising
an electronic
controller operably connectable to the electrically controllable restrictor to
control the
electrically controllable restrictor.
[0024] In some embodiments, the biasing member comprises one or more springs.
[0025] In some embodiments, the one or more springs are partially compressed
in all
configurations of the lung simulator.
[0026] In some embodiments, the one or more springs are partially extended in
all
configurations of the lung simulator.
[0027] In some embodiments, the biasing member comprises a non-linear spring
mechanism for providing a non-linear force with respect to the volume of the
lung bladder.
[0028] In some embodiments, the simulator has a compliance tube and a valve
connectable to the compliance bladder and to an air source for controlling the
adjustable
volume of the compliance bladder.
[0029] A second broad aspect is a lung simulation system for simulating
ventilated lung
breathing mechanics, the system including: at least one lung simulator, and a
ventilation
source, wherein the ventilation source is connected to the at least one lung
simulator to
simulate one or more of a controlled, assisted and autonomous ventilation, or
a
combination thereof.
[0030] A third broad aspect is a lung simulation system for simulating
ventilated lung
breathing mechanics, the system including: a manikin; and one of at least one
lung
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simulator and a lung simulation system as described herein.
[0031] In some embodiments, the manikin may comprise one or more tubes
connecting
said one or more restrictor to the mouth of the manikin.
Brief Description of the Drawings
[0032] The invention will be better understood by way of the following
detailed description
of embodiments of the invention with reference to the appended drawings, in
which:
[0033] FIG. 1 is a block diagram of an exemplary prior art lung simulator
external rack
which may be connected to a manikin to simulate human lungs;
[0034] FIG. 2A is an illustration of an exemplary passive lung simulator with
a biasing
system comprising a linear biasing member and a compliance bladder;
[0035] FIG. 2B is a schematic of an exemplary lung simulator with a biasing
system
comprising multiple springs under extension that pull together plates acting
on the lung
bladder;
[0036] FIG. 2C is a schematic of an exemplary lung simulator with an example
of a non-
linear biasing system comprising a spring pulling a cable wrapped around a
spiral wheel
coupled to a circular spool pulling on cables connected to plates compressing
a lung
bladder;
[0037] FIG. 3 is an illustration of the volume change of an exemplary lung
simulator when
ventilated;
[0038] FIG. 4 is a graph representing human pulmonary function in terms of
volume
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versus pressure;
[0039] FIG. 5A is a combination of a schematic of the preloading of an
exemplary biasing
member for a biasing system comprising a deflated compliance bladder and its
associated graph of force versus spring extension;
.. [0040] FIG. 5B is a combination of a schematic of the preloading of an
exemplary biasing
member for a biasing system comprising a partially inflated compliance bladder
resulting
in a high compliance lung simulator, its associated graph of force versus
spring extension
and its associated Volume versus Pressure graph;
[0041] FIG. 5C is a combination of a schematic of the preloading of an
exemplary biasing
member for a biasing system comprising a partially inflated compliance bladder
resulting
in a normal compliance lung simulator, its associated graph of force versus
spring
extension and its associated Volume versus Pressure graph;
[0042] FIG. 5D is a combination of a schematic of the preloading of an
exemplary biasing
member for a biasing system comprising a fully inflated compliance bladder
resulting in a
low compliance lung simulator, its associated graph of force versus spring
extension and
its associated Volume versus Pressure graph;
[0043] FIG. 6A is a schematic of an exemplary double lung simulator with a
single air
restrictor in a manikin;
[0044] FIG. 6B is a schematic of an exemplary double lung simulator with
double air
restrictor in a manikin;
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[0045] FIG. 7 is a schematic of an exemplary double lung simulator with a
single
compliance bladder;
[0046]
[0047] FIG. 8 is a schematic of an exemplary lung simulator connected to a
ventilation
source through a tube and a restrictor;
[0048] FIG. 9 is a schematic of an exemplary lung simulator with the lung
bladder
connected to a ventilation source through a tube and a restrictor and the
compliance
bladder connected to an air source through a tube and a valve;
[0049] FIG. 10 is a schematic of an exemplary lung simulator connected to both
a
ventilation source and an air source for a compliance bladder and in which a
controller
controls the restrictor and air source valve;
[0050] FIG. 11A is a schematic representing an exemplary decomposed lung
simulator
with two separate compartments;
[0051] FIG. 11B is a schematic representing an exemplary decomposed lung
simulator
with two separate compartments and a piston system controlling the air volume
of the
lung bladder's compartment;
[0052] FIG. 12A is an illustration of an exemplary passive lung simulator with
a biasing
system comprising a linear biasing member, a compliance bladder and an
overdistension
spring; and
[0053] FIG. 12B is an illustration of an exemplary passive lung simulator with
a biasing
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system comprising a linear biasing member, a compliance bladder and an
overdistension
spring fixed on a bladder.
Detailed Description
[0054] The present disclosure relates to a lung simulator providing a reliable
and
physiologically representative pulmonary response to a mechanical ventilator
or any other
type of ventilation source connected to the lung simulator for medical
professional
training. Such simulators allow medical professionals to learn how to use
ventilators and
other ventilation sources safely before working with human or animal patients.
[0055] Lung simulators are well known in the art and have been used in
training manikins
for years. However, these lung simulators have certain significant
shortcomings, such as
an excessive size or not representing faithfully an actual lung function.
Current accurate
lung simulators that produce human-like responses when under ventilation
typically
require equipment racks or components that are external to the manikin in
which the lung
parts reside. Otherwise, smaller lung simulators that may fit completely
inside a manikin
either do not reproduce human-like pulmonary response or may not be easily
adapted to
simulate different medical lung conditions without replacing parts of the
simulator.
[0056] Additionally, smaller lung simulators do not have the ability to
simulate a patient
that requires controlled and assisted ventilation with the same equipment and
the ability
to switch from one form of ventilation to the other in a single continuous
simulation.
[0057] It will be understood that references to bladders, such as a lung
bladder and a
Date Recue/Date Received 2021-03-29
compliance bladder, herein represent any component that takes an air input and
outputs
a displacement. As such, they may be air bags, bellows, syringes, pistons or
any other
similar components. Additionally, references to springs should be understood
to include
any biasing member which may absorb and release energy (i.e. elastics, bungee
cords,
non-linear springs with various shapes, etc.)
[0058] A person skilled in the art will further appreciate that, although the
lung simulator
may be herein described as being connectable to a ventilator to simulate
ventilation, it
may also be connected to any other type of ventilation used by medical
practitioners (e.g.
bag mask, human ventilation during mouth-to-mouth procedures, etc.) without
departing
from the teachings of this disclosure. The term ventilation source may also be
used herein
to refer to all aforementioned types of sources providing air to the simulated
patient's lung
system.
[0059] Prior Art
[0060] FIG. 1 is a block diagram of an exemplary prior art lung simulator
external rack
which may be connected to a manikin to simulate human lungs. In order to
adequately
simulate several medical conditions affecting human lungs, this high-precision
lung
simulator requires a significant number of components. This exemplary prior
art system
requires a vaporizer 15, a universal simulator engine controller 17 for
various components
of the rack, bellows 19, mass flow controllers 21, a syringe pump 23, a non-
invasive blood
pressure (NIBP) processor 25 for processing NIBP data and a gas analyzer 27 in
order
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to simulate the human lungs.
[0061] The lung simulator external rack illustrated in the block diagram of
FIG. 1 is
intended to cooperate with other components of the lung simulation system
mounted
inside the manikin. These components are also significantly voluminous, such
that they
limit the ability to add other simulators in the same manikin. Moreover, the
volume of the
parts makes them difficult to fit in a pediatric manikin. Additionally, the
size of this external
rack makes it impractical for transportation.
[0062] Passive lung simulator
[0063] A passive lung simulation system simulates lungs that are completely
dependent
on a ventilation source over the entire respiratory cycle. Such systems may
also be
referred to as controlled ventilation systems, as opposed to assisted
ventilation and
spontaneous breathing systems. Assisted ventilation system simulate lungs that
can
initiate inhalations but rely on a ventilation source for the remainder of the
respiratory
cycle. Spontaneous breathing systems simulate lungs that can complete
respiratory
cycles without any assistance from a ventilation source.
[0064] FIG. 2A is a schematic illustration of an exemplary passive lung
simulator. The
lung simulator may be encased in an external frame 35 that may limit the
external volume
to which all other components may expand to and provide a structure to which
other
components may be attached. The lung simulator has two other main component
sections, a lung section 47 and a biasing system section 45.
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[0065] The lung section 47 of FIG. 2A comprises a lung bladder 29 and may
comprise a
lung fixed plate 43 and a lung floating plate 41. The lung bladder 29 is a
bladder which is
connectable to a tube to receive air from a ventilation source and may
thereafter inflate
and deflate like a human lung. The lung fixed plate 43 is a plate that may be
fixed, at its
first side, to the frame 35 and, at its opposite side, to a first side of the
lung bladder 29,
such that the movement of the lung bladder 29 is restricted. On the other side
of the lung
bladder 29, the lung floating plate 41 may be fixed to the lung bladder 29 in
order to
distribute evenly the force to the rest of the system when the lung bladder 29
is inflated
or deflated.
[0066] The biasing system section 45 is responsible for simulating lung
compliance. The
passive lung simulator of FIG. 2A includes a compliance fixed plate 37, a
biasing member
33 (e.g. a spring element), a compliance floating plate 39 and a compliance
bladder 31.
The compliance fixed plate 37 may serve to fix the biasing member 33 to the
frame 35.
The biasing member 33, which may be a compression spring, may further be fixed
to a
compliance floating plate 39 to evenly distribute the spring load to the
compliance bladder
31 and to the lung section 47.
[0067] The biasing member 33 is required to produce a force to deflate the
lung bladder
29 when the air pressure inside the lung bladder 29 lowers, as it would during
a relaxed
human expiration.
[0068] The compliance bladder 31 is a component that may be inflated or
deflated such
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that the biasing member 33 is compressed into a desired state for the purposes
of
simulating any number of lung compliance states, as will be described
hereinafter.
[0069] It will be understood by a person skilled in the art that the
embodiment presented
in FIG. 2A, in which the biasing member 33 is a spring element configured to
exert a force
against a receiving surface of the compliance floating plate 39, may be
adapted to enable
a more even distribution of the force across the receiving surface by
positioning more
than one biasing member 33against the receiving surface. It will also be
understood that
the biasing system section 45 may have one or more tension springs instead of
compression springs. Additionally, the order of the arrangement of the two
bladders, the
plates and the biasing member may be changed in several different
configurations, i.e.
the lung bladder and its mating plates may be above or below the biasing
system, or the
latter may be between two or more components of the biasing system.
[0070] Reference is now made to FIG. 2B, illustrating a schematic of an
exemplary lung
simulator with a biasing system 45 comprising multiple biasing members 33,
which may
be linear biasing members such as springs. The lung simulator may comprise a
frame 35
enclosing the biasing system 45, to which the lung bladder 29 and the
compliance bladder
31 are directly attached. FIG. 2B further demonstrates direct bladder contact,
such that
no floating plates may be required. The biasing members 33 of the biasing
system 45
comprises a number of tension springs which are fixed to the frame 35. Other
embodiments may comprise an upper and a lower fixed plate that would be
situated
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between the frame 35 and the bladders for fixing the biasing members 33. The
biasing
members 33 can be arranged in apertures within the lung bladder 29.
[0071] FIG. 2C is a schematic of an exemplary lung simulator in which the
biasing system
45 comprises a non-linear biasing mechanism. This embodiment of the lung
simulator
comprises a frame 35 enclosing a lung bladder 29 and a compliance bladder 31.
The
biasing members 33 providing the relaxed expiration force to the lung bladder
29, such
that it deflates to a positive end-expiratory pressure when positive air
pressure is not
received from the ventilation source, may be non-linear and may comprise
cables or wires
59 in enclosures. In the embodiments presented in FIG. 2C, the biasing system
45
includes a spring 49 applying a constant force to a first cam or spool 55
through a
connected wire 51. The first cam 55 may be connected to a second cam 57
through a
common shaft 53 and the wires 59 effectively pulling the frame 35 are fixed to
the second
cam 57.
[0072] This exemplary mechanical system allows the use of special shapes of
cams, such
that it may replicate a human lung compliance profile by varying the force
applied to the
wires 59. As a matter of fact, the design of the radius of cam 55 at any one
point, can be
used to relate to the volume of air inside the bladders. Someone skilled in
the art will
appreciate that the force applied to the wires 59 is a function of the radius
of the cam 55.
[0073] It will be understood by a person skilled in the art that any
equivalent mechanical
system that produces a variable force to be applied to the lung section 47 may
be used
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without departing from the present teachings, whether it is linear or non-
linear and
regardless of the number of components included in the system.
[0074] FIG. 3 is an illustration of the volume change of an exemplary lung
simulator when
ventilated. FIG. 3 will be better understood when analyzed in combination with
FIG. 4,
which is a graph representing human pulmonary function in terms of volume
versus
pressure.
[0075] FIG. 4 illustrates that human breathing is done between a positive end-
expiratory
pressure (PEEP) 61, which is the positive pressure that remains in the human
lungs after
a complete expiration, and a peak inspiratory pressure (PIP) 63, which is the
maximum
pressure in the lungs after a complete inhalation.
[0076] FIG. 3 shows the tidal volume, which relates to the volume change in
the lung
bladder 29 between the PIP 63 and PEEP 61 (see FIG. 4), and the compression
effect
that this volume change has on the lung floating plate 41 and the compliance
floating
plate 39. In this embodiment, the compressibility of the compliance bladder 31
is
negligible compared to the volume change of the lung bladder 29, and, as such,
the
displacement of the lung floating plate 41 is completely reciprocated at the
compliance
floating plate 39. The spring element 33 is therefore compressed to a state
corresponding
to the volume gain of the lung bladder 29.
[0077] FIG. 4 further illustrates the effect of lung compliance and airway
resistance. The
biasing system 45 provides a simulation of the lung static compliance (equal
to the change
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in volume over the change in pressure), and the dynamic compliance portion is
simulated
through the airway resistance. As will be further described hereinafter, the
airway
resistance is the result of the combination of every component between the
ventilation
source and the lung bladder 29.
[0078] FIG. 5A is a schematic of the preloading of an exemplary biasing member
for a
biasing system comprising a deflated compliance bladder. The embodiment of
FIG. 5A
illustrates a lung simulator setup 65 using no precompression of the biasing
member 33
(in this embodiment, a spring element) by the biasing system 45. The simulator
setup 65,
which includes the lung section 47 in addition to the compliance bladder 31,
therefore has
a fully deflated compliance bladder, or, in yet other embodiments, may not
include any
compliance bladder.
[0079] This embodiment thus makes use of a biasing member 33 which is a
compression
spring element at its lowest force-displacement ratio. As is known in the art,
a linear spring
element has a constant force-displacement ratio, such that for low
displacement values,
the force required is low and high displacement values are only reached with
higher force
applied to the linear spring element. Using a linear compression spring as the
biasing
member 33 may effectively yield in different compliance simulations depending
on the
initial compression of the spring member. However, someone skilled in the art
will
appreciate that, although a linear compression spring is herein illustrated
and described,
other biasing members may be used as alternatives. Additionally, non-linear
spring
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elements may be used in other embodiments without departing from the teachings
of this
disclosure. FIG. 5A demonstrates the displacement resulting from the volume
change of
the lung bladder 29 in an area 67.
[0080] Using a spring element as the biasing member 33 between its zero
position and
the maximum displacement caused by the volume gain of the lung bladder 29
represents
the highest possible lung compliance that may be reached by this combination
of spring
element and simulator setup 65. In some embodiments, this highest lung
compliance
value is equivalent to the highest possible human lung compliance value.
[0081] FIG. 5B is a schematic of the preloading of an exemplary biasing member
for a
biasing system comprising a partially inflated compliance bladder resulting in
a high
compliance lung simulator. Similar to the embodiment shown in FIG. 5A, this
embodiment
illustrates a pre-compressed state of a linear spring element, which is used
as the biasing
member 33, by using the lung simulator setup 65 in a configuration for which
the
compliance bladder 31 is partially filled. The resulting volume of the
combined compliance
bladder 31 (fixed volume) and the lung bladder 29 (inflates and deflates) has
the biasing
member 33 move in the area 69 between an initial position Xa and a final
position Xb.
[0082] The initial position Xa corresponds to the compressed state of the
biasing member
33 when the lung bladder 29 is filled at PEEP volume. Similarly, the final
position Xb
corresponds to the compressed state of the biasing member 33when the lung
bladder 29
filled at PIP volume.
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[0083]The embodiment of FIG. 5B presents a high lung compliance curve 73, at a
compliance value between a normal human lung compliance 71 and the highest
compliance value achievable by the lung simulator.
[0084]FIG. 5C is a schematic of the preloading of an exemplary biasing member
for a
biasing system comprising a partially inflated compliance bladder resulting in
a normal
compliance lung simulator. The embodiment of FIG. 5C is similar to the one of
FIG. 5B
but simulates normal human lung compliance 71. Thus, the simulator setup 65
has a
compliance bladder 31 partially inflated to a higher volume than that of FIG.
5B, such
that the displacement of the linear spring element (i.e. biasing member 33) is
done
between an initial position Xb and a final position Xc (area 75) that relates
to a normal
human lung compliance profile 71.
[0085]FIG. 5D is a schematic of the preloading of an exemplary biasing member
for a
biasing system comprising a fully inflated compliance bladder resulting in a
low
compliance lung simulator. FIG. 5D, which represents the simulator using the
compliance bladder 31 at its maximum volume, features the lowest lung
compliance 79
achievable by the lung simulator. This has the biasing member 33 move in the
area 77
between an initial position Xc and a final position Xd.
[0086]It will be appreciated that FIGs. 5A to 5D present both threshold and
normal cases
and that inflating the compliance bladder 31 to any desired volume between its
zero and
maximum volume may simulate any static lung compliance value without having to
change the biasing member 33. Thus, choosing an adequate biasing member 33
that
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Date Recue/Date Received 2022-03-04
allows variation between the lowest and highest physiologically possible
values of human
lung compliance is beneficial.
[0087] A person skilled in the art will understand that, despite FIGs. 5A to
5D illustrating
a biasing system with a linear compression spring, any biasing system with any
other
method of applying force to the lung bladder 29 may be used, such that the
lung bladder
29 may be deflated down to PEEP and that a certain lung compliance may be
simulated.
[0088] FIG. 6A is a schematic of an exemplary double lung simulator with a
single air
restrictor 85 in a manikin 81. In this embodiment, the manikin 81 has a mouth
to interface
with a mechanical ventilator equipment, or to any other type of ventilation
source, and to
which a proximal tube 83 is connected for the air to be ultimately supplied to
the lung
bladders. This proximal tube 83 may have an air restrictor 85 which further
allows the
single air supply to be split into two distal tubes 87. These distal tubes 87
interface with
the lung bladders of lung simulators 91 that may be enclosed in a single
housing 89.
[0089] The air restrictor 85 may be any mechanism that may impede air flow to
a certain
level. In some embodiments, the air restrictor 85 is a part of the tube
itself, such that the
internal diameter of the tube is chosen to introduce enough airway resistance
to simulate
human airways. The preferred embodiment uses a valve as an air restrictor 85,
which is
controlled, manually or electronically, to open to a certain degree in order
to impede the
air flow to a desired level. Any type of valve, such as a mechanical butterfly
valve or an
electromechanical valve, may be used. It will be appreciated that any method
of air flow
Date Recue/Date Received 2021-03-29
control may be used without departing from the teachings of this disclosure.
[0090] In other embodiments, the manikin 81 has a single lung simulator 91
that simulates
both human lungs. In yet another embodiment, both lung simulators 91 resides
in
separate housings in order to allow different placement options inside the
manikin 81.
Additionally, other possible embodiments include a single lung simulator with
two
separate lung bladders 29, as will be presented hereinafter.
[0091] FIG. 6B is a schematic of an exemplary double lung simulator with
double air
restrictors 85 in a manikin 81. Similarly to the manikin 81 of FIG. 6A, the
manikin 81 of
FIG. 6B comprises the lung simulators 91 in the housing 89. The difference in
the
embodiment of FIG. 6B resides in the tubing which provides the air from a
ventilation
source to the lung simulators 91. Thus, the manikin 81 may have a single
proximal tube
83 which may run from the mouth of the manikin 81 and may split into two split
tubes 87
at a distal end. Each one of the split tubes 87 may thereafter have the air
restrictor 85,
such that different air restrictions may be applied to each one of the lung
simulators 91.
In this embodiment, both of the air restrictors 85 are controllable valves.
[0092] In some embodiments, there is any number of the lung simulators 91 used
in the
manikin 81 and any number of the air restrictors 85, such that smaller lung
simulators
with small lung bladders may be used to simulate bigger lungs (e.g. using a
number of
pediatric lung simulators to simulate an adult patient).
[0093] FIG. 7 is a schematic of a lung simulator with compliance bladder 31
and several
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Date Recue/Date Received 2021-03-29
biasing members 33 arranged to guide plate 39 to move parallel to plate 41.
This
embodiment may be used to simulate lungs having different airway resistance,
which may
be desirable with respect to the simulator illustrated in FIG. 6B. Thus, the
base lung
simulator of FIG. 2A may be adapted to use two smaller lung bladders 29
instead of a
single bigger one (as the total volume of the lung bladders should be the same
and
equivalent to the volume of the desired average human, adult or infant, to be
simulated).
The use of two separate lung bladders 29 may therefore allow the simulation of
certain
medical conditions which could affect only one lung.
[0094] The embodiment presented in FIG. 7 further illustrates the use of side
sliders 93
which are fixed to any one of the floating plates 39, 41, or to both floating
plates, such
that the movement of the floating plates may be restricted to the direction in
which the
bladders' inflation and deflation displaces the biasing system. In some
embodiments, the
sliders 93 include additional physical supports to ensure that the floating
plates remain
parallel to the fixed plates 37, 43 such that the force applied to the
compliance bladder
31 or to the lung bladder 29 is evenly distributed.
[0095] FIG. 7 further illustrates a complete frame 35 to house the lung
bladder 29, the
biasing member 33 and the fixed and floating plates 37-43.
[0096] The embodiment of FIG. 7 can be adapted to provide a double lung
simulator with
two compliance bladders 31 and multiple spring elements 33. Similar to the
embodiment
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Date Recue/Date Received 2021-03-29
shown in FIG. 7, this embodiment may be used to simulate lungs with different
airway
resistances and with imbalanced lung compliance. The two compliance bladders
31 may
thus be volume-controlled by filling to different volume levels.
[0097]While the embodiment of FIG. 7 shows compression springs 33 acting on
plate 39,
.. it will be understood that springs can be arranged in tension to pull plate
39 against
bladder 31 and/or 29. When working in tension, the role of a side sliders 93
acting as a
guiding structure to keep a parallel movement between plates 39 and 41 can be
reduced
as the tension springs can be arranged to maintain parallel alignment.
[0098]In some embodiments, there may be any number of lung bladders 29 and
compliance bladders 31. The lung simulator can have a network of lung bladders
that are
each connected to a tube that merges with one or more tubes into one tube
connectable
to a ventilation source. Any number of restrictors may be used to restrict air
flow supplied
to one or more lung bladders. The use of multiple smaller bladders may be
beneficial
when the outer form factor of the lung simulator is limited to a given height.
It may also
allow for better control of different compliances in zones, such as for
simulating different
upper and lower airway resistances.
[0099]FIG. 8 is a schematic of an exemplary lung simulator connected to a
ventilation
source 95 through a tube 87 and a restrictor 85. In this embodiment, the
compliance
bladder is not connected to any source as it is pre-filled to the desired
volume to achieve
a given lung compliance. The lung bladder is the only part that is connected
to an external
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Date Recue/Date Received 2022-03-04
air source, the ventilation source 95, which may be any type of air source
such as a
mechanical ventilator, a bag mask or a human engaging in mouth-to-mouth
procedures.
[00100] The ventilation source 95 may be any other type of ventilator that may
be used
for patient ventilation or a ventilator simulator that provides similar inhale
and exhale
support functions. The connection between the lung bladder and the ventilation
source
95 can be a hose or tube coupling, for example, for connecting to a hose or
tube of a
ventilator, a manikin face having oral and nasal air passages connected to the
lung
bladder by tubing for coupling with a ventilator mask, bag mask or for a mouth-
to-mouth
exercise, or any other suitable type of coupling.
[00101] The ventilation source 95 may be connected to the mouth of a manikin
through
tube 87, when the lung simulator is included in a manikin shell. The
embodiment of FIG.
8 further comprises an air restrictor 85 positioned along the length of the
tube 87, which
is a controllable valve that allows for changing the airflow supplied to the
lung bladder in
a manner that simulates airway resistance. The air restrictor 85 may also be
any type of
air flow impeding device, such as an internal cross-section reduction device.
[00102] FIG. 9 is a schematic of an exemplary lung simulator with the lung
bladder
connected to a ventilation source 95 through a tube 87 and a restrictor 85.
The
compliance bladder of the lung simulator is connected to an air source 97
through a tube
87 and a valve 86. The lung bladder may be inflated by the connected
ventilation source
95 as described in the embodiment of FIG. 8. FIG. 9 further provides a way to
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Date Recue/Date Received 2022-03-04
control the inflation and deflation of the compliance bladder such that its
volume may be
changed during a simulation or between different simulations without having to
connect
new tubing between the simulations. In this preferred embodiment, the
compliance
bladder is thus connected to an air source 97, which may be any type of source
that
provides air (or any suitable fluid), such as a compressed air bottle or a
compressor. The
air source 97 is connected through a tube 87 and a valve 86.
[00103] The valve 86 may be a controllable valve that can be opened or closed
manually or electrically in order to modify the air supply to the compliance
bladder.
Deflation of the compliance bladder may be done either through valve 86, when
equipped
with a bleeding mechanism, or if the air source 97 is a compressor, by
stopping the
compressor and opening the valve. Other means may also be used in order to
deflate the
compliance bladder, but the preferred embodiment allows doing so without
unplugging
the tube.
[00104] FIG. 10 is a schematic of an exemplary lung simulator connected to
both the
ventilation source 95 and the air source 97, in which a controller 99 controls
the restrictor
85 and valve 86. In this embodiment, the controller 99, which is a computer
running a
control software or a simple electronic controller with switches, variable
knobs or the like.
Depending on the type of air restrictor used in the lung simulation system,
the controller
99 may control an open-close position or a variable opening.
[00105] Additionally, the use of the controller 99 controlling the valve 86
may provide
Date Recue/Date Received 2021-03-29
the ability to dynamically change the lung simulator's compliance throughout a
breathing
cycle. This may allow for the simulation of many types of medical conditions,
e.g.
overdistension for low lung compliance. To do so, the controller 99 may allow
more air to
fill the compliance bladder when the lung bladder volume approaches PIP
volume, such
that the increased volume in the compliance bladder creates a higher biasing
system
resistance, which simulates overdistension. The controller 99 may operate the
valve 86
based on a preprogrammed schedule (e.g. if the simulation starts with a fully
closed
restrictor 85 and the controller opens the restrictor 85 at a given time and
knows the
airflow settings of the ventilation source 95, it may increase and decrease
the compliance
bladder volume at given time intervals). In some embodiments, similarly to the
embodiments of FIGs. 12A to 12C, the controller 99 is connected to a number of
sensors
in order to receive information that can be used to determine and control
which part of the
inhalation-exhalation the system is performing. Therefore, the controller 99
may control
the compliance bladder's volume based on a sensor reading.
[00106] FIG. 11A is a schematic representing an exemplary decomposed lung
simulator with two separate compartments 103, 107. Some applications of the
lung
simulator may include incorporating the simulator in confined locations, such
as in a
manikin comprising simulators of other organs or in a pediatric manikin. In
such cases, it
may be beneficial to separate the lung simulator in components allowing for
the smallest
possible component to be included inside a manikin while the remaining part of
the system
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Date Recue/Date Received 2021-03-29
may be outside of the manikin.
[00107] For example, including only the lung bladder portion in a manikin,
while keeping
the biasing system outside, may allow for the manikin's chest to show
pulmonary function
(displacement of the thoracic cage related to an inhalation or exhalation)
while
.. significantly reducing the required space inside the manikin's chest.
[00108] FIG. 11A thus illustrates an embodiment in which the lung bladder 29
is
confined in a first compartment 103 that is airtight, such that when the
ventilation source
95 is connected to the lung bladder 29 and inflates or deflates the lung
bladder, the
compartment's air volume surrounding the lung bladder 29 decreases or
increases. This
first compartment 103 is connected to a second compartment 107 through tubing
105 to
allow transfer of the air between the compartments.
[00109] The second compartment 107 may therefore include a biasing system as
described herein, which may include the compliance bladder 31 and a spring
element 33.
The air volume change of the first compartment 103 due to the inflation or
deflation of the
lung bladder 29 thus results in the reciprocating compression or extension of
the biasing
system. As would be understood by a person skilled in the art, this decomposed
system
may be used in a similar manner as described in other figures of the present
disclosure.
[00110] Active lung simulator
[00111] As previously described, the lung simulator may be a passive or active
system.
The passive system presented previously is compatible with the controlled
ventilation
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Date Recue/Date Received 2021-03-29
mode, meaning the connected ventilation source compensates for a complete
absence
of patient lung function.
[00112] Training medical professionals in the use of ventilators and any other
ventilation
source may require the ability to simulate a patient that requires a
ventilation mode other
than controlled ventilation, as some patients may only require assisted
ventilation, where
the patient is able to initiate the inhalation effort but is not able to
complete a full inhalation.
It is also possible that a patient changes states from requiring controlled
ventilation to
requiring assisted ventilation, or the opposite, while remaining connected to
the ventilator.
Similarly, the patient may change from requiring a ventilator to being able to
breathe by
himself, which will be herein referred to as autonomous breathing as the
patient does not
necessitate support from a ventilator. Therefore, it may be beneficial to have
a simulator
capable of seamlessly changing modes of operations between controlled,
assisted and
autonomous ventilation modes.
[00113] Reference is now made to FIG. 11B which is a schematic representing an
.. exemplary decomposed lung simulator with two separate compartments 103, 107
and a
piston system 106 controlling the air volume 104 of the lung bladder's 29
compartment
103. This embodiment is similar to the embodiment presented in FIG. 11A but
allows the
lung simulator to be used in any mode of ventilation (i.e. controlled,
assisted and
autonomous) instead of being limited to a controlled ventilation mode.
[00114] The compartment 103 containing the lung bladder 29 may be connected to
a
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Date Recue/Date Received 2021-03-29
cylinder that includes a piston 106. As such, the air volume surrounding the
lung bladder
29 may be in communication with the cylinder's air. An actuator 108 may be
operable to
displace the piston 106 inside the cylinder, such that the air volume change
inside the
cylinder directly impacts the volume of air in the connected lung and
compliance
compartments 103, 107.
[00115] Therefore, pulling the piston 106 reduces the pressure applied to the
lung
bladder 29 and thus simulates a patient's initiation of an inhalation.
Operating in such a
way allows the system to operate in the assisted and controlled ventilation
modes.
Depending on the operation of the actuator 108 moving the piston 106, the mode
of
operation may be changed to any other during a simulation.
[00116] It will be understood by a person skilled in the art that the actuator
108 and
piston 106 system may be changed to any other system operating similarly (i.e.
to control
the volume of air surrounding the lung bladder 29) such as using a bellow or a
syringe.
[00117] Another embodiment which provides the ability to simulate any mode of
ventilation includes the use of an actuator instead of the biasing system of
the passive
lung simulator. The actuator may be activated to move the lung bladder such
that a small
negative pressure is created in the bladder, triggering the ventilator to
assist in the
ventilation, similarly to a patient able to initiate an inhalation.
Furthermore, the actuator
may be used to completely change the volume of the lung bladder in order to
simulate a
patient being able to autonomously breathe. Thus, the actuator may be used in
any similar
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Date Recue/Date Received 2021-03-29
fashion as the sum of human muscles exercising a force on the human lungs to
allow
breathing.
[00118] Additionally, the use of an actuator may provide the ability to
dynamically
change the compliance of the lung simulator throughout a breathing cycle,
which opens
the possibilities to simulate any type of medical conditions, e.g.
overdistension for low
lung compliance.
[00119] Overdistension simulation in passive lung simulators
[00120] Although the use of an actuator may have several benefits, such as
reduction
of the number of parts of the lung simulator while still allowing the
simulation of a medical
condition, similar simulation results may be obtained with mechanical parts.
[00121] FIG. 12A illustrates an exemplary passive lung simulator with a
biasing system
comprising a linear biasing member, a compliance bladder and an overdistension
spring
123. The addition of an overdistension spring 123 in the biasing system allows
for this
simple configuration to provide a way to simulate alveolar overdistension
(static
compliance regionally reduced at the end of an inhalation). When the lung
bladder is filled
with air and reaches a certain volume that is close to the PIP volume, the
overdistension
spring 123 begins to provide resistance to the compliance floating plate.
Therefore, the
total resistance of the biasing system increases when the lung bladder is
inflated close to
PIP volume, which simulates overdistension.
[00122] Similarly, FIG. 12B illustrates an exemplary passive lung simulator
with a
Date Recue/Date Received 2021-03-29
biasing system comprising a linear biasing member, a compliance bladder and an
overdistension spring 123 fixed on a bladder 125. In this embodiment, the
addition of a
bladder 125 to which the overdistension spring 123 is fixed allows to easily
change the
value of the overdistension that should be applied in the simulation. With a
filled bladder
125, the resistance would be higher and thus the overdistension would be high,
whereas
an empty bladder 125 may apply little or no resistance to the system, such
that there is
limited overdistension or no overdistension for the simulated lungs. The air
supplied to
the bladder 125 may further be controlled between or during simulations.
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