U.S. patent application number 17/244728 was filed with the patent office on 2021-12-02 for inverted container hydrostatic ventilator.
This patent application is currently assigned to The Government of the United States of America, as represented by the Secretary of Homeland Security. The applicant listed for this patent is The Government of the United States of America, as represented by the Secretary of Homeland Security, The Government of the United States of America, as represented by the Secretary of Homeland Security. Invention is credited to Bryson Jacobs, Savannah Lyle.
Application Number | 20210370013 17/244728 |
Document ID | / |
Family ID | 1000005579779 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210370013 |
Kind Code |
A1 |
Jacobs; Bryson ; et
al. |
December 2, 2021 |
INVERTED CONTAINER HYDROSTATIC VENTILATOR
Abstract
In an example, a ventilator includes an outer container
containing liquid, an inverted container submerged in the liquid to
provide inverted container space between a closed top and an inner
container liquid level; gas supply line to supply breathing gas to
the inverted container space; and inhalation line having an inlet
in the inverted container space to provide breathing gas to
patient. The inverted container moves upward from a first elevation
when the inverted container space reaches a hydrostatic delivery
pressure and volume of the inverted container space increases. The
inverted container stops moving upward and the gas supply line
stops supplying when the inverted container reaches a second
elevation above the first. Based on a breath demand signal or
preset timing, the inhalation line opens to permit flow of
breathing gas to the patient at the hydrostatic delivery pressure,
lowering the inverted container due to lost buoyancy resulting in
sinkage.
Inventors: |
Jacobs; Bryson; (Quaker
Hill, CT) ; Lyle; Savannah; (Saint Petersburg,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Government of the United States of America, as represented by
the Secretary of Homeland Security |
Washington |
DC |
US |
|
|
Assignee: |
The Government of the United States
of America, as represented by the Secretary of Homeland
Security
Washington
DC
|
Family ID: |
1000005579779 |
Appl. No.: |
17/244728 |
Filed: |
April 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
17096479 |
Nov 12, 2020 |
11033706 |
|
|
17244728 |
|
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|
63030005 |
May 26, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 16/16 20130101;
A61M 16/208 20130101; A61M 2205/3348 20130101; A61M 16/0003
20140204 |
International
Class: |
A61M 16/16 20060101
A61M016/16; A61M 16/00 20060101 A61M016/00; A61M 16/20 20060101
A61M016/20 |
Goverment Interests
STATEMENT OF GOVERNMENT INTEREST
[0002] The present invention was made by employees of the United
States Department of Homeland Security in the performance of their
official duties. The U.S. Government has certain rights in this
invention.
Claims
1. A ventilator comprising: an outer container having a closed
bottom and an open top to contain a liquid inside the outer
container; an inverted container having a closed top and an open
bottom, the open bottom of the inverted container being submerged
in the liquid of the outer container to provide an inner container
liquid level inside the inverted container and an outer container
liquid level between the inverted container and the outer
container, the inverted container including an inverted container
wall surrounded by an outer container wall of the outer container,
the open bottom of the inverted container being spaced from the
closed bottom of the outer container by an elevation which is
variable, the inverted container having an inverted container space
between the closed top and the inner container liquid level, the
inner container liquid level and the outer container liquid level
being measured relative to the closed bottom of the outer
container; a gas supply line to supply a breathing gas to the
inverted container space; and an inhalation line having an
inhalation inlet in the inverted container space and an inhalation
outlet outside of the liquid and the inverted container to provide
the breathing gas from the inverted container space to a patient;
the inverted container being configured to move upward from a first
elevation position when the breathing gas in the inverted container
space reaches a hydrostatic delivery pressure and to continue
moving upward at the hydrostatic delivery pressure while a volume
of the inverted container space increases at the hydrostatic
delivery pressure, the inverted container being configured to stop
moving upward and the gas supply line being configured to stop
supplying the breathing gas to the inverted container space when
the inverted container reaches a second elevation position; the
inhalation line being configured to open to permit a flow of the
breathing gas from the inhalation inlet in the inverted container
space to the inhalation outlet coupled to the patient at the
hydrostatic delivery pressure, lowering the elevation of the
inverted container; and the inhalation line being configured to
close and the gas supply line being configured to supply the
breathing gas to the inverted container space when the inverted
container has reached-a the first elevation position lower than the
second elevation position, lifting the elevation of the inverted
container at the hydrostatic delivery pressure inside the inverted
container space.
2. The ventilator of claim 1, wherein the inhalation line is
configured to open to permit the flow of the breathing gas from the
inhalation inlet in the inverted container space to the inhalation
outlet coupled to the patient at the hydrostatic delivery pressure,
lowering the elevation of the inverted container, based on one of
(1) detection of a patient breath demand signal or (2) a first
preset timing.
3. The ventilator of claim 2, further comprising: an exhalation
line having an exhalation inlet to receive exhaled gas from the
patient and an exhalation outlet disposed in the liquid between the
inverted container wall and the outer container wall at a fixed
elevation relative to the closed bottom of the outer container, the
fixed elevation being at a submerged depth measured from the outer
container liquid level of the liquid and being selected to set a
target hydrostatic backpressure.
4. The ventilator of claim 3, wherein when the inverted container
has reached the first elevation position, the exhalation line is
opened to permit an exhalation gas flow from the patient through
the exhalation inlet to the exhalation outlet disposed in the
liquid between the inverted container wall and the outer container
wall, the gas supply line supplies the breathing gas to flow to the
inverted container space, lifting the elevation of the inverted
container.
5. The ventilator of claim 4, wherein based on one of (1) detection
of the target hydrostatic backpressure at the exhalation outlet or
(2) a second preset timing, the exhalation line is configured to be
closed to stop the exhalation gas flow from the exhalation inlet to
the exhalation outlet in the liquid at the fixed elevation.
6. The ventilator of claim 5, further comprising: an inhalation
sensor coupled with the inhalation line to detect the patient
breath demand signal; a first elevation sensor to detect when the
inverted container reaches the first elevation position; and a
second elevation sensor to detect when the inverted container
reaches the second elevation position.
7. The ventilator of claim 1, further comprising: an inhalation
valve disposed in the inhalation line and being configured to be
opened to permit the breathing gas to flow from the inhalation
inlet to the inhalation outlet or be closed to block the breathing
gas from flowing from the inhalation inlet to the inhalation
outlet; and an exhalation valve disposed in an exhalation line and
being configured to be opened to permit an exhalation gas to flow
from an exhalation inlet to an exhalation outlet or be closed to
block the exhalation gas from flowing from the exhalation inlet to
the exhalation outlet.
8. The ventilator of claim 7, further comprising: a bubbler
disposed in the liquid below the inverted container space, wherein
the gas supply line has a gas supply outlet terminating at the
bubbler to form bubbles that flow up to the inverted container
space; a bubbler bypass line coupled between the gas supply line
and the inhalation line to direct the breathing gas to bypass the
bubbler and flow from the gas supply line via the inhalation line
to the inverted container space; and a bubbler bypass valve
disposed in the bubbler bypass line and being configured to be
closed to direct the breathing gas to flow to the gas supply outlet
terminating at the bubbler or to be opened to direct the breathing
gas to bypass the bubbler and flow to the inverted container
space.
9. The ventilator of claim 7, wherein the inhalation line and the
exhalation line merge, at a junction downstream of the inhalation
valve and upstream of the exhalation valve, into a single patient
breathing line to be coupled to the patient.
10. A method of supporting breathing of a patient, the method
comprising: placing an inverted container having a closed top and
an open bottom in an outer container having a closed bottom and an
open top and containing a liquid inside the outer container, the
open bottom of the inverted container being submerged in the liquid
of the outer container to provide an inner container liquid level
inside the inverted container and an outer container liquid level
between the inverted container and the outer container, the
inverted container including an inverted container wall surrounded
by an outer container wall of the outer container, the open bottom
of the inverted container being spaced from the closed bottom of
the outer container by an elevation which is variable, the inverted
container having an inverted container space between the closed top
and the liquid, the inner container liquid level and the outer
container liquid level being measured from the closed bottom of the
outer container; supplying a breathing gas via a gas supply line to
the inverted container space, the inverted container configured to
move upward from a first elevation position when the breathing gas
in the inverted container space reaches a hydrostatic delivery
pressure and to continue moving upward at the hydrostatic delivery
pressure while a volume of the inverted container space increases
at the hydrostatic delivery pressure, the inverted container being
configured to stop moving upward and the gas supply line being
configured to stop supplying the breathing gas to the inverted
container space when the inverted container reaches a second
elevation position; placing an inhalation line having an inhalation
inlet in the inverted container space and an inhalation outlet
outside of the liquid and the inverted container to provide the
breathing gas from the inverted container space to the patient;
opening the inhalation line to permit a flow of the breathing gas
from the inhalation inlet in the inverted container space to the
inhalation outlet coupled to the patient at the hydrostatic
delivery pressure, lowering the elevation of the inverted
container; and closing the inhalation line and supplying the
breathing gas via the gas supply line to the inverted container
space when the inverted container has reached the first elevation
position lower than the second elevation position, lifting the
elevation of the inverted container at the hydrostatic delivery
pressure inside the inverted container space.
11. The method of claim 10, wherein the inhalation line is opened
to permit the flow of the breathing gas from the inhalation inlet
in the inverted container space to the inhalation outlet coupled to
the patient at the hydrostatic delivery pressure, lowering the
elevation of the inverted container, based on one of (1) detection
of a patient breath demand signal or (2) a first preset timing.
12. The method of claim 11, further comprising: placing an
exhalation line having an exhalation inlet to receive exhaled gas
from the patient and an exhalation outlet disposed in the liquid
between the inverted container wall and the outer container wall at
a fixed elevation relative to the closed bottom of the outer
container, the fixed elevation being at a submerged depth measured
from the outer container liquid level of the liquid and being
selected to set a target hydrostatic backpressure.
13. The method of claim 12, further comprising: when the inverted
container has reached the first elevation position, opening the
exhalation line to permit an exhalation gas flow from the patient
through the exhalation inlet to the exhalation outlet disposed in
the liquid between the inverted container wall and the outer
container wall, and supplying the breathing gas via the gas supply
line to the inverted container space, lifting the elevation of the
inverted container.
14. The method of claim 13, further comprising: based on one of (1)
detection of the target hydrostatic backpressure at the exhalation
outlet or (2) a second preset timing, closing the exhalation line
to stop the exhalation gas flow from the exhalation inlet to the
exhalation outlet in the liquid at the fixed elevation.
15. The method of claim 14, further comprising: detecting the
patient breath demand signal using an inhalation sensor coupled
with the inhalation line; detecting when the inverted container
reaches the first elevation position using a first elevation
sensor; and detecting when the inverted container reaches the
second elevation position using a second elevation sensor.
16. The method of claim 10, further comprising: coupling an
inhalation valve to the inhalation line, the inhalation valve being
configured to be opened to permit the breathing gas to flow from
the inhalation inlet to the inhalation outlet or be closed to block
the breathing gas from flowing from the inhalation inlet to the
inhalation outlet; and coupling an exhalation valve to an
exhalation line having an exhalation inlet to receive exhaled gas
from the patient, the exhalation valve being configured to be
opened to permit an exhalation gas to flow from the exhalation
inlet to an exhalation outlet or be closed to block the exhalation
gas from flowing from the exhalation inlet to the exhalation
outlet.
17. The method of claim 16, further comprising: connecting a
bubbler to a gas supply outlet of the gas supply line, the bubbler
being disposed in the liquid below the inverted container space to
form bubbles from the breathing gas which flow up to the inverted
container space; coupling a bubbler bypass line between the gas
supply line and the inhalation line to direct the breathing gas to
bypass the bubbler and flow from the gas supply line via the
inhalation line to the inverted container space; and connecting a
bubbler bypass valve to the bubbler bypass line, the bubbler bypass
valve being configured to be closed to direct the breathing gas to
flow to the gas supply outlet terminating at the bubbler or to be
opened to direct the breathing gas to bypass the bubbler and flow
to the inverted container space.
18. The method of claim 16, further comprising: merging the
inhalation line and the exhalation line, at a junction downstream
of the inhalation valve and upstream of the exhalation valve, into
a single patient breathing line to be coupled to the patient.
19. A ventilator comprising: an outer container having a closed
bottom and an open top to contain a liquid inside the outer
container; an inverted container having a closed top and an open
bottom, the open bottom of the inverted container being submerged
in the liquid of the outer container to provide an inner container
liquid level inside the inverted container and an outer container
liquid level between the inverted container and the outer
container, the inverted container including an inverted container
wall surrounded by an outer container wall of the outer container,
the open bottom of the inverted container being spaced from the
closed bottom of the outer container by an elevation which is
variable, the inverted container having an inverted container space
between the closed top and the liquid, the inner container liquid
level and the outer container liquid level being measured from the
closed bottom of the outer container; means for directing a
breathing gas to the inverted container space, to move the inverted
container upward from a first elevation position when the breathing
gas in the inverted container space reaches a hydrostatic delivery
pressure, to continue moving the inverted container upward at the
hydrostatic delivery pressure while a volume of the inverted
container space increases at the hydrostatic delivery pressure, to
stop moving the inverted container upward when the inverted
container reaches a second elevation position higher than the first
elevation position, and to move the inverted container upward at
the hydrostatic delivery pressure when the inverted container drops
from the second elevation position to the first elevation position;
an inhalation line having an inhalation inlet in the inverted
container space and an inhalation outlet outside of the liquid and
the inverted container to provide the breathing gas from the
inverted container space to a patient; the inhalation line being
configured to open to permit a flow of the breathing gas from the
inhalation inlet in the inverted container space to the inhalation
outlet coupled to the patient at the hydrostatic delivery pressure,
lowering the elevation of the inverted container; and the
inhalation line being configured to close when the inverted
container has reached the first elevation position.
20. The ventilator of claim 19, wherein the inhalation line is
configured to open to permit the flow of the breathing gas from the
inhalation inlet in the inverted container space to the inhalation
outlet coupled to the patient at the hydrostatic delivery pressure,
lowering the elevation of the inverted container, based on one of
(1) detection of a patient breath demand signal or (2) a first
preset timing.
21. The ventilator of claim 20, further comprising: an exhalation
line having an exhalation inlet to receive exhaled gas from the
patient and an exhalation outlet disposed in the liquid between the
inverted container wall and the outer container wall at a fixed
elevation relative to the closed bottom of the outer container, the
fixed elevation being at a submerged depth measured from the outer
container liquid level of the liquid and being selected to set a
target hydrostatic backpressure.
22. The ventilator of claim 21, further comprising: means for
directing an exhalation gas flow, when the inverted container has
reached the first elevation position, to permit the exhalation gas
flow from the patient through the exhalation inlet to the
exhalation outlet disposed in the liquid between the inverted
container wall and the outer container wall, and, based on one of
(1) detection of the target hydrostatic backpressure at the
exhalation outlet or (2) a second preset timing, to stop the
exhalation gas flow from the exhalation inlet to the exhalation
outlet in the liquid at the fixed elevation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The application is a continuation of U.S. application Ser.
No. 17/096,479, filed Nov. 12, 2020, entitled INVERTED CYLINDER
HYDROSTATIC VENTILATOR, which is a nonprovisional of and claims the
benefit of priority from U.S. Provisional Patent Application No.
63/030,005, filed on May 26, 2020, entitled INVERTED CYLINDER
HYDROSTATIC VENTILATOR, the entire disclosures of which are
incorporated by reference.
FIELD
[0003] The discussion below relates generally to systems and
methods of providing mechanical ventilation by moving breathable
air into and out of lungs of a patient.
BACKGROUND
[0004] A ventilator is a machine that supports breathing by
delivering oxygen into the lungs of an individual and removing
carbon dioxide from the body. It uses positive pressure to deliver
air into the lungs of a patient. The patient may exhale the air or
the ventilator can do it for the patient. In a typical system, a
mechanical ventilator blows air, or air with increased oxygen,
through tubes into the patient's airways. The air flowing to the
patient passes through a humidifier, which warms and moistens the
air. A mask can be used on the patient's mouth and nose to deliver
the air. In some cases, an endotracheal tube goes through the
patient's mouth and into the windpipe.
SUMMARY
[0005] Embodiments of the present invention are directed to systems
and methods for providing mechanical ventilation by moving
breathable air into and out of lungs. One type of system employs
positive pressure to produce ventilation.
[0006] According to specific embodiments, the positive pressure
ventilation system is most simply described as a cylinder within a
cylinder. A larger cylinder is upright, closed at the bottom and
open at the top, and partially filled with water, typically
distilled water. A smaller cylinder is inverted, open at the bottom
and closed at the top, and immersed in the water bath, trapping air
within. Static pressure head can be produced by either introducing
more air into the inner cylinder and holding it stationary, thereby
pushing the water down and out of its open bottom, or by physically
pushing the inner cylinder downward while leaving the amount of
trapped air the same. The concept uses both of these principles to
produce a steady and metered airflow (the tidal breath) at a
prescribed pressure (via downward force exerted on the inner
bucket). The inner cylinder vertically reciprocates between a
minimum elevation and a maximum elevation, providing breathing air
to the patient; the amount of vertical travel determines the volume
of air delivered. Adjustable PEEP (Positive End-Expiratory
Pressure) is provided via variable-depth exhalation tubing placed
into the water bath; the deeper the tube's end, the greater the
back pressure against which a patient must exhale.
[0007] In some embodiments, the ventilation system employs
components that can be fabricated with minimal electronics or no
microcontroller, so as to create a low-cost ventilator which can be
easily reproduced at remote locations with limited supplies and
equipment. Working prototypes have been fabricated, for instance,
from flat acrylic sheet ("square" cylinders) or assembled from
glass vases exhibiting desirable geometry (approximately 3 to 5
inches in diameter and 16 to 20 inches in height). Plastic
resistant to UV-C light is desirable as the primary material,
although prefabricated cylinders meeting this and the geometric
constraints have been difficult to locate; graduated cylinders
ranging from 2 to 4 liters are one possibility.
[0008] In accordance with an aspect of the present invention, a
ventilator comprises: an outer container having a closed bottom and
an open top to contain a liquid inside the outer container; an
inverted container having a closed top and an open bottom, the open
bottom of the inverted container being submerged in the liquid of
the outer container to provide an inner container liquid level
inside the inverted container and an outer container liquid level
between the inverted container and the outer container, the
inverted container including an inverted container wall surrounded
by and spaced by an annular space from an outer container wall of
the outer container, the open bottom of the inverted container
being spaced from the closed bottom of the outer container by an
elevation which is variable, the inverted container having an
inverted container space between the closed top and the inner
container liquid level, the inner container liquid level and the
outer container liquid level being measured relative to the closed
bottom of the outer container; a gas supply line to supply a
breathing gas to the inverted container space; and an inhalation
line having an inhalation inlet in the inverted container space and
an inhalation outlet outside of the liquid and the inverted
container to provide the breathing gas from the inverted container
space to a patient. The inverted container is configured to move
upward from a preset minimum elevation position when the breathing
gas in the inverted container space reaches a hydrostatic delivery
pressure and to continue moving upward at the hydrostatic delivery
pressure while a volume of the inverted container space increases
at the hydrostatic delivery pressure. The inverted container is
configured to stop moving upward and the gas supply line being
configured to stop supplying the breathing gas to the inverted
container space when the inverted container reaches a preset
maximum elevation position. Based on one of (1) detection of a
patient breath demand signal or (2) a first preset timing, the
inhalation line is configured to open to permit a flow of the
breathing gas from the inhalation inlet in the inverted container
space to the inhalation outlet coupled to the patient at the
hydrostatic delivery pressure, lowering the elevation of the
inverted container due to lost buoyancy resulting in sinkage. The
inhalation line is configured to close and the gas supply line is
configured to supply the breathing gas to the inverted container
space when the inverted container has reached the preset minimum
elevation position, lifting the elevation of the inverted container
at the hydrostatic delivery pressure inside the inverted container
space.
[0009] In accordance with another aspect of the invention, a method
of supporting breathing of a patient comprises: placing an inverted
container having a closed top and an open bottom in an outer
container having a closed bottom and an open top and containing a
liquid inside the outer container, the open bottom of the inverted
container being submerged in the liquid of the outer container to
provide an inner container liquid level inside the inverted
container and an outer container liquid level between the inverted
container and the outer container, the inverted container including
an inverted container wall surrounded by and spaced by an annular
space from an outer container wall of the outer container, the open
bottom of the inverted container being spaced from the closed
bottom of the outer container by an elevation which is variable,
the inverted container having an inverted container space between
the closed top and the liquid, the inner container liquid level and
the outer container liquid level being measured from the closed
bottom of the outer container; supplying a breathing gas via a gas
supply line to the inverted container space, the inverted container
configured to move upward from a preset minimum elevation position
when the breathing gas in the inverted container space reaches a
hydrostatic delivery pressure and to continue moving upward at the
hydrostatic delivery pressure while a volume of the inverted
container space increases at the hydrostatic delivery pressure, the
inverted container being configured to stop moving upward and the
gas supply line being configured to stop supplying the breathing
gas to the inverted container space when the inverted container
reaches a preset maximum elevation position; placing an inhalation
line having an inhalation inlet in the inverted container space and
an inhalation outlet outside of the liquid and the inverted
container to provide the breathing gas from the inverted container
space to the patient; based on one of (1) detection of a patient
breath demand signal or (2) a first preset timing, opening the
inhalation line to permit a flow of the breathing gas from the
inhalation inlet in the inverted container space to the inhalation
outlet coupled to the patient at the hydrostatic delivery pressure,
lowering the elevation of the inverted container; and closing the
inhalation line and supplying the breathing gas via the gas supply
line to the inverted container space when the inverted container
has reached the preset minimum elevation position, lifting the
elevation of the inverted container at the hydrostatic delivery
pressure inside the inverted container space.
[0010] In accordance with yet another aspect of this invention, a
ventilator comprises: an outer container having a closed bottom and
an open top to contain a liquid inside the outer container; an
inverted container having a closed top and an open bottom, the open
bottom of the inverted container being submerged in the liquid of
the outer container to provide an inner container liquid level
inside the inverted container and an outer container liquid level
between the inverted container and the outer container, the
inverted container including an inverted container wall surrounded
by and spaced by an annular space from an outer container wall of
the outer container, the open bottom of the inverted container
being spaced from the closed bottom of the outer container by an
elevation which is variable, the inverted container having an
inverted container space between the closed top and the liquid, the
inner container liquid level and the outer container liquid level
being measured from the closed bottom of the outer container; a
mechanism for directing a breathing gas to the inverted container
space, to move the inverted container upward from a preset minimum
elevation position when the breathing gas in the inverted container
space reaches a hydrostatic delivery pressure, to continue moving
the inverted container upward at the hydrostatic delivery pressure
while a volume of the inverted container space increases at the
hydrostatic delivery pressure, to stop moving the inverted
container upward when the inverted container reaches a preset
maximum elevation position, and to moving the inverted container
upward at the hydrostatic delivery pressure when the inverted
container drops from the preset maximum elevation position to the
preset minimum elevation position; an inhalation line having an
inhalation inlet in the inverted container space and an inhalation
outlet outside of the liquid and the inverted container to provide
the breathing gas from the inverted container space to a patient;
based on one of (1) detection of a patient breath demand signal or
(2) a first preset timing, the inhalation line being configured to
open to permit a flow of the breathing gas from the inhalation
inlet in the inverted container space to the inhalation outlet
coupled to the patient at the hydrostatic delivery pressure,
lowering the elevation of the inverted container; and the
inhalation line being configured to close when the inverted
container has reached the preset minimum elevation position.
[0011] Other features and aspects of various examples and
embodiments will become apparent to those of ordinary skill in the
art from the following detailed description which discloses, in
conjunction with the accompanying drawings, examples that explain
features in accordance with embodiments. This summary is not
intended to identify key or essential features, nor is it intended
to limit the scope of the invention, which is defined solely by the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The attached drawings help explain the embodiments described
below.
[0013] FIG. 1 shows a schematic view of an inverted cylinder
hydrostatic ventilator (ICHV) system including an ICHV
apparatus.
[0014] FIGS. 2A-2H schematically illustrate the operation of an
ICHV apparatus according to an embodiment.
[0015] FIG. 2A shows the ICHV apparatus in an initial charging
process from startup State 0 in bubble-conditioning mode.
[0016] FIG. 2B shows the ICHV apparatus in a charging process with
tidal volume addition to a ready-to-deliver State 1 in
bubble-conditioning mode.
[0017] FIG. 2C shows the ICHV apparatus in the ready-to-deliver
State 1.
[0018] FIG. 2D shows the ICHV apparatus in a breath-delivery
process from State 1 to a breath-delivered State 2.
[0019] FIG. 2E shows the ICHV apparatus in the breath-delivered
State 2 ready for charging in non-conditioning mode.
[0020] FIG. 2F shows the ICHV apparatus in a
charging-and-expiration process from State 2 to State 1 in
non-conditioning mode.
[0021] FIG. 2G shows the ICHV apparatus in the ready-to-deliver
State 1.
[0022] FIG. 2H shows the ICHV apparatus in a breath-delivery
process from State 1 to State 2.
[0023] FIG. 3A shows an example of a breath demand mode water
switch, for switching on and off of the inhalation valve for
on-demand breathing instead of mandatory breathing, in a neutral
state.
[0024] FIG. 3B shows the breath demand mode water switch of FIG. 3A
in an active state.
[0025] FIG. 4 is a flow diagram summarizing the process of
operating the ICHV apparatus of FIGS. 2A-2H.
[0026] FIG. 5 is a schematic view illustrating an example of
proximity sensors in an ICHV apparatus.
[0027] FIG. 6 is a schematic view illustrating another example of a
proximity sensor in an ICHV apparatus.
[0028] FIG. 7 is a schematic view illustrating an example of a
heater and a UV light in an ICHV apparatus.
[0029] FIG. 8 schematically illustrates an ICHV apparatus according
to another embodiment.
[0030] FIG. 9 schematically illustrates an ICHV apparatus according
to another embodiment.
[0031] FIG. 10 shows an example of a PEEP tube terminating in its
own separate sterilization reservoir with permeable membrane shown
near the top of the free surface.
[0032] FIG. 11 is a modified version of the ICHV apparatus of FIG.
8 showing an example of a smaller reservoir of water treated with a
sterilizing agent, hydraulically separated from the main water
bath, for housing the reentrant PEEP tube terminus.
[0033] FIG. 12 shows a graph of available tidal volume, added mass,
and maximum unit height versus delivery pressure of the ICHV
apparatus of FIG. 8.
[0034] FIG. 13 illustrates an example of a controller or computing
system including logic.
[0035] FIGS. 14A-14G show an example of controller logic for
operating an ICHV system according to an embodiment of the
invention.
DETAILED DESCRIPTION
[0036] A number of examples or embodiments of the present invention
are described, and it should be appreciated that the present
invention provides many applicable inventive concepts that can be
embodied in a variety of ways. The embodiments discussed herein are
merely illustrative of ways to make and use the invention and are
not intended to limit the scope of the invention. Rather, as will
be appreciated by one of skill in the art, the teachings and
disclosures herein can be combined or rearranged with other
portions of this disclosure along with the knowledge of one of
ordinary skill in the art.
[0037] The design philosophy according to embodiments of the
present invention is to keep the design, its applied physics, and
user interface as simple and visually intuitive as possible. The
design principles take advantage of water's abilities to provide
static pressure head, low-tolerance sealing, humidification and
warming, and viral decontamination when treated with ultraviolet
(UV) light and/or increased salinity.
[0038] In some embodiments, the simplicity and viability of this
design concept is realized. It may be low-tech, but it is highly
visual to end-operators and reliable with little need for tight
tolerances between moving parts. It merely uses the principles of
buoyancy, displacement, and gravity through clever geometric
manipulation.
ICHV System and Operation
[0039] FIG. 1 shows a schematic view of an inverted cylinder
hydrostatic ventilator (ICHV) system 100 including an ICHV
apparatus 110. The ICHV apparatus 110 is connected to a patient
mask 120 to be placed over the patient's face to deliver breathing
air to the patient's lungs. A controller 130 may be used to control
operation of the ICHV apparatus 110 and delivery of breathing air
via the mask 120 to the patient.
ICHV Apparatus
[0040] FIGS. 2A-2H schematically illustrate the operation of an
ICHV apparatus according to an embodiment. The ICHV apparatus 200
includes an upright outer cylinder 202 having a closed bottom and
an open top and containing a water bath 204, and an inverted inner
cylinder 206 having an open bottom submerged in the water bath 204
of the upright cylinder or upright container 202 and a closed top
208 above the water bath 204. The inner cylinder 206 is configured
to move up and down along guide rails provided inside the upright
cylinder 202. The inner cylinder 206 can be restrained from lateral
motion by a variety of sliding supports. Vertical guide rails
running parallel to the inner cylinder 206 and connected via
sliprings is one method. In one example, a 3D printed "lid skid"
upon which valves, breath demand manometer, controller, and air
pump(s) are mounted; lateral motion of the inner cylinder 206 is
arrested by a rigid sleeve of slightly larger diameter than the
inner cylinder's outer diameter and extending approximately 12.5 cm
down into the outer cylinder 202. The sleeve's length inhibits
tipping of the inner cylinder 206 while its loose fit minimizes
friction, while rotation about the vertical axis is permitted.
Protrusions may extend inward from the outer container wall(s) of
the outer cylinder 202 providing resistance to lateral motion and
rotation of the inner cylinder 206 while permitting vertical
translation.
[0041] The inverted cylinder or inverted container 206 includes a
gas volume in an inverted cylinder space 210 trapped by the water
bath 204 in the upright cylinder 202, in the inverted cylinder
space or inverted container space 210 above an inverted inner
cylinder free water surface 212. The gas volume in the inverted
cylinder space 210 can expand or contract. Adjustable cylinder
weights may be disposed on top of the inverted cylinder 206 to
control the pressure in the gas volume, which is set by selecting
an amount of the weights. The open bottom of the inverted container
206 is spaced from the closed bottom of the outer container 202 by
a variable elevation. The inverted container 206 is configured to
move upward from a preset minimum elevation position when the
breathing gas in the inverted container space 210 reaches a
hydrostatic delivery pressure and to continue moving upward at the
hydrostatic delivery pressure while a volume of the inverted
container space 210 increases at the hydrostatic delivery pressure,
the inverted container 206 being configured to stop moving upward
when the inverted container 206 reaches a preset maximum elevation
position.
[0042] In one embodiment, a maximum volume proximity sensor, such
as a maximum volume lower limit switch, is disposed at a location
above the inverted cylinder 206 to control the maximum gas volume.
A minimum volume proximity sensor is disposed at a location below
the closed top 208 of the inverted cylinder 206 to control the
minimum gas volume. For example, the minimum volume proximity
sensor, such as a minimum volume upper limit switch, is located
along the guide rails. The minimum volume proximity sensor is
tripped (e.g., electrically, magnetically, mechanically,
acoustically, or optically) when the inverted cylinder 206 drops to
a preset minimum height or elevation level and activates the
minimum volume proximity sensor (see FIGS. 5 and 6 below).
[0043] When gas is introduced into the inverted cylinder space 210
via a gas supply line or tube 220 (e.g., by an air pump 221), the
pressure increases until it is sufficient to expand the gas volume
and lift the weight of the inverted cylinder 206 and any weight
placed thereon. The pressure is the hydrostatic delivery pressure.
During expansion of the gas volume at the hydrostatic delivery
pressure via introduction of more gas, the inverted cylinder 206
moves upward and then stops moving upward when the inverted
cylinder 206 reaches a preset maximum elevation position or level
and the maximum volume proximity sensor or maximum elevation sensor
is activated. During contraction of the gas volume at the
hydrostatic delivery pressure due to escaping of the gas (via an
inhalation tube or patient gas delivery tube 222 as described
below), the inverted cylinder 206 sinks downward and then stops
moving downward when the minimum volume proximity sensor or minimum
elevation sensor is activated. The proximity sensors can be
adjusted to set a variable maximum gas volume and/or a variable
minimum gas volume, the difference between the two defining the
tidal breath. The proximity sensors may be electrically activated
by electrical contact, magnetically controlled electrical switches
(reed switches), mechanically activated, or ultrasonically or
optically ranged and activated, for example.
[0044] A bubbler bypass valve (one-way) 230 is provided on a
bubbler bypass line or tube 232. The bubbler bypass valve 230 may
be closed to allow the breathing gas to be supplied via the gas
supply line 220 to a gas supply outlet terminating at a bubbler 234
submerged in the water bath 204 if enhanced humidification is
desired in a bubble-conditioning mode. The bubbler 234 is disposed
at a location below the inverted inner cylinder free water surface
212 and at or above the open bottom of the inverted cylinder 206,
for the breathing gas or breathable gas to egress and bubble up
through the water bath 204 prior to entering the trapped gas volume
(i.e., bubble mode), thereby serving as a conditioning gas supply
outlet.
[0045] An inhalation or inspiratory valve or patient gas delivery
valve (one-way) 240 is provided on a patient supply (or patient gas
delivery) or inhalation line or tube 222 to supply breathing gas,
in an opened position, from the inhalation inlet 224 disposed in
the gas volume of the inverted cylinder space 210 to the
patient.
[0046] When the gas supply operates in a non-conditioning mode
where bubbles are not desired, the bubbler bypass valve 230 is
opened to direct the breathing gas through the inhalation line 222,
which now serves as the non-conditioning gas supply line. The
breathing gas is flowed directly via the line 222 exiting the
non-conditioning gas supply outlet 224 to the inverted cylinder
space 210 of the inverted cylinder 206 at the location above the
inverted inner cylinder water free surface 212, bypassing the
bubbler 234 to preclude the formation of bubbles (i.e., direct
injection mode).
[0047] The ICHV apparatus 200 is designed to deliver the breathing
gas from the gas volume of the inverted cylinder space 210 to the
patient at a constant delivery pressure. The prescribed pressure is
the target hydrostatic delivery pressure as determined by the total
weight of the inner cylinder 206 and any additional weights placed
on the inner cylinder 206. When the prescribed pressure (as
represented by the outer cylinder water height at the outer
cylinder free water surface 244 above the inner cylinder water
height at the inner cylinder free water surface 212) is reached,
the addition of more breathing gas via the gas supply line will
cause the inner cylinder 206 to buoyantly rise until the maximum
elevation is reached and the maximum volume proximity sensor is
activated. The additional volume introduced into the gas volume of
the rising inner cylinder 206 corresponds to a tidal volume. As
such, the height of the maximum volume proximity sensor such as a
maximum volume lower limit switch determines the delivered tidal
volume. The tidal volume is the volume of breathing gas delivered
to the patient's lungs with each breath by the ICHV system.
Historically, initial tidal volumes were set at 10 to 15 mL/kg of
actual body weight for patients with neuromuscular diseases. It can
be adjusted by medical professionals for different patients based
on their needs.
[0048] An exhalation line or tube 252 has an exhalation inlet to
receive exhaled gas from the patient and an exhalation outlet 256
to release the exhaled gas. An exhalation or expiratory valve
(one-way) 250 is provided on the exhalation line 252 to permit
exhaled breath of the patient to flow, in an opened position, from
the exhalation inlet coupled to the patient (e.g., via a mask) to
the exhalation outlet 256 in the water bath 204 of the upright
cylinder 202. The exhalation line 252 terminates at the exhalation
outlet 256 at a desired elevation which is selected and fixed for
operation at the fixed elevation relative to the closed bottom of
the outer container 202, in an annular region 258 between the
upright cylinder 202 and the inverted cylinder 206, outside of the
inverted cylinder 206. A target hydrostatic backpressure is set by
a submerged depth of the exhalation outlet 256 of the exhalation
line 252 in the water bath 204, which is the depth measured from
the outer container liquid level 244 between the inverted inner
cylinder 206 and the upright outer cylinder 202. As such, an
adjustable PEEP (Positive End-Expiratory Pressure) is provided via
variable-depth exhalation outlet 256 placed into the water bath
204. The depth can be adjusted based on the patient's ventilation
need as determined by the medical professionals. The depth can
further be changed as the patient's ventilation need changes.
[0049] An inhalation valve 240 is disposed in the inhalation line
222 and is configured to be opened to permit the breathing gas to
flow from the inhalation inlet 224 to the inhalation outlet or be
closed to block the breathing gas from flowing from the inhalation
inlet 224 to the inhalation outlet. An exhalation valve 250
disposed in the exhalation line 252 and being configured to be
opened to permit an exhalation gas to flow from the exhalation
inlet to the exhalation outlet 256 or be closed to block the
exhalation gas from flowing from the exhalation inlet to the
exhalation outlet 256.
[0050] In this embodiment, the inhalation line 222 and the
exhalation line 252 merge, outside of the outer and inner cylinders
202, 206, at a junction 262 into a single patient breathing line
260 coupled to the patient (serving as inhalation line when air
flows to the patient or exhalation line when air flows from the
patient). The junction 262 is disposed downstream of the inhalation
valve 240 and upstream of the exhalation valve 250. Disposed
between the junction 262 and the patient is a manometer 270
containing a non-toxic electrolytic liquid 274. This is an example
of a breath demand mode water switch for switching on and off of
the inhalation valve 240 in the inhalation line 222 for on-demand
breathing instead of mandatory breathing. The manometer 270 is
disposed between the inhalation valve 240 and a breathing line
opening 266 of the single patient breathing line 260 coupled to the
patient, which is the inhalation outlet during inhalation by the
patient and the exhalation inlet during exhalation by the patient.
Details of its operation are shown in FIGS. 3A-3B and described
below.
[0051] The bubbler bypass valve 230, inhalation valve 240, and
exhalation valve 250 may be solenoid valves. Solenoid air valves
are relatively low-pressure valves operated by a signal from a
low-voltage relay. These three valves are turned on and off by the
controller based on sensor inputs in the on-demand breathing mode.
In contrast, in the mandatory breathing mode, the three valves are
all programmed to open and close automatically at specific times in
the breathing cycle. The ICHV apparatus of FIGS. 2A-2H is capable
of operating in the on-demand breathing mode and the mandatory
breathing mode.
[0052] There are two hydrostatic pressures of interest in the ICHV
apparatus. The first is the delivery pressure of breathing gas
delivered from the gas volume in the inverted cylinder space 210 of
the inverted cylinder 206 to the patient during inhalation. The
second is the necessary exhalation backpressure against which the
patient must exhale in order to avoid collapse of the alveoli in
the lungs (also known as positive-end expiratory pressure, or
PEEP). The depth of the exhalation outlet 256 of the exhalation
line 252 determines the amount of PEEP the patient should
experience during exhalation (this backpressure is hydrostatically
generated). In contrast, the weight of the inner cylinder 206
determines the breathing gas delivery pressure (the more weight,
the higher the delivery pressure). This delivery pressure is
immediately exhibited by the difference in height between the
water's free surface location 244 at an outer container liquid
level within the outer cylinder 202 (the annular space 258 between
the inner cylinder 206 and the outer cylinder 202) and its free
surface 212 within the inner cylinder 206 at an inner container
liquid level. The inner container liquid level at the inner
cylinder's free surface 212 will always be lower than the outer
container liquid level of the outer cylinder's free surface 244
(the height difference corresponds to the hydrostatic delivery
pressure). Delivery pressure and available delivered volume exhibit
an inverse relationship (i.e., at a higher delivered pressure, less
gas will be available for delivery, due to the location of the
inverted inner cylinder free water surface 212 being limited by the
cylinder's open end rim); therefore, the design's geometric limits
should consider the question as to what the largest volume needs to
be delivered at the highest pressure. A possible embodiment to
increase pressure and volume range could be clamping geometrically
similar extensions to the open ends of the inner and outer
cylinders, allowing base units to be relatively compact for
shipment and less-intensive use, but geometrically expanded for
patients requiring more tidal volume, more pressure, or both.
Operation of ICHV Apparatus
[0053] FIG. 2A shows the ICHV apparatus in an initial charging
process from startup State 0 in the bubble-conditioning mode. In
this start-up step, the open bottom of the inverted inner cylinder
206 is submerged inside the water bath 204 of the upright outer
cylinder 202 with the gas volume inside the inverted cylinder space
210 above the inverted cylinder free water surface 212. The
exhalation outlet 256 of the exhalation line 252 is submerged in
the annular space 258 of the water bath 204 between the inner
cylinder 206 and the outer cylinder 202 at a submerged depth or
elevation selected to set a target hydrostatic backpressure.
[0054] The bubbler bypass valve 230 is closed to direct the supply
of the breathing gas to flow to the inverted cylinder space 210.
The inhalation valve 240 is closed. The exhalation valve 250 is
opened so that the patient is free to exhale into the water bath
204 via the exhalation tube 252 having the exhalation outlet end
256 terminating at a preset depth based on the prescribed positive
end-expiratory pressure (PEEP). The inverted inner cylinder 206 is
neutrally buoyant, at its lowest elevation, and ready to be filled
with breathing gas. The breathing gas begins displacing water out
of the inverted cylinder 206 and building pressure. In this way,
the inverted cylinder 206 is prefilled with breathing gas in the
gas volume of the inverted cylinder space 210 to set a delivery
pressure (as represented by the outer cylinder water height at the
outer cylinder free water surface 244 above the inner cylinder
water height at the inner cylinder free water surface 212). The
inner cylinder 206 is sensed to be at the preset minimum height.
The breathing gas supply source, an air pump 221 in this case,
energizes and delivers air to the inverted cylinder 206. When
running in bubble-conditioning mode, the system delivers gas to the
bottom of the water bath 204 where it passes through the bubbler
234 and ascends into the inner cylinder 206, making it begin to
rise.
[0055] FIG. 2B shows the ICHV apparatus in a charging process in
the bubble-conditioning mode, with tidal volume addition as the
apparatus progresses to a ready-to-deliver State 1. The air pump
221 continues to deliver air to the inverted cylinder space 210 via
the bubbler 234 to form diffused, humidified, and warmed bubbles
until the inner cylinder 206 has risen to a preset height based on
the prescribed tidal volume to be delivered. The inverted cylinder
206 becomes positively buoyant and rises at constant pressure as
breathing gas fills the available gas volume of the inverted
cylinder space 210 to add the tidal volume. The patient is still
free to exhale into the water bath 204 via the exhalation line 252
with the exhalation outlet 256 at the preset depth based on the
prescribed PEEP.
[0056] FIG. 2C shows the ICHV apparatus in the ready-to-deliver
State 1. The inner cylinder 206 achieves its maximum height or
elevation and the air source de-energizes (e.g., by turning off the
air pump 221). For example, the maximum volume proximity sensor
trips upon contact with the risen inverted cylinder 206 and signals
the air pump 221 to turn off via the controller. The prescribed
tidal volume is achieved as the closed top 208 of the inverted
inner cylinder 206 (or the weight disposed on top) contacts the
terminal of the maximum volume proximity sensor and completes the
sensor circuit, signaling the gas supply flow to stop via the
controller. The apparatus is ready to deliver the breathing gas to
the patient.
[0057] When a breath is sensed as being demanded (on-demand
breathing) or when a first preset timing or time limit is reached
(mandatory breathing), the inhalation valve 240 separating the
trapped breathing gas supply 210 from the patient opens, allowing
the gas to escape directly to the patient. The exhalation valve 250
for the PEEP tube 252 closes at the same time. For example, if
operated in the on-demand breathing mode as opposed to the
mandatory breathing mode, the apparatus awaits a patient breath
demand signal, which can be detected, for instance, by a breath
demand pressure or vacuum sensor or an inhalation sensor (e.g.,
manometer 270) disposed between the inhalation valve 240 and the
patient and sensing a pressure drop and generating a breath demand
signal by the inhalation sensor. The apparatus may sense a partial
vacuum inhalation demand from the patient via the breath demand
pressure sensor, the controller opens the inhalation valve 240, and
gas escapes from the gas volume inside the inverted cylinder space
or chamber 210 of the inverted cylinder 206 via the patient supply
or inhalation tube 222. The inverted cylinder 206 sinks at constant
pressure and velocity due to gravity.
[0058] In the on-demand breathing operation, the patient breath
demand signal is used to open the inhalation valve 240.
Alternatively, in a mandatory breathing operation, the controller
opens the inhalation valve 240 to allow a preset amount of
inhalation time for inhalation and closes the inhalation valve 240
to allow a preset amount of exhalation time for exhalation at
preset timings.
[0059] FIG. 2D shows the ICHV apparatus in a breath-delivery
process from State 1 to a breath-delivered State 2. The inner
cylinder 206 continues to sink lower at constant velocity due to
gravity as gas is conveyed to the patient at the pressure indicated
by the vertical disparity between the water bath's lower free
surface 212 within the inner cylinder 206 and upper free surface
244 of the outer cylinder 202. The breathing gas delivery flow rate
is determined mostly by the breathing tube diameter of the
inhalation line 222 (and of the patient breathing line 260 beyond
the junction 262) and the pressure drop through the inhalation
valve 240. When the inner cylinder 206 reaches its minimum height,
the process recycles.
[0060] FIG. 2E shows the ICHV apparatus in the breath-delivered
State 2 ready for charging in the non-conditioning mode (as opposed
to charging in the bubble-conditioning mode of FIG. 2B). The
inverted cylinder 206 has sunken to the minimum elevation,
delivering a prescribed amount of breathing gas (tidal volume) from
the gas volume of the inverted cylinder space 210 to the patient.
For example, the minimum volume proximity sensor, when activated,
signals the controller to close the inhalation valve and open the
exhalation valve. The exhalation backpressure (i.e., the PEEP) is
hydrostatically provided via the water in the cylindrical bucket or
container 202 and strategic placement of the exhalation outlet port
256 of the exhalation line 252 in the water column or bath 204, as
discussed above. The exhalation line 252 is opened to permit an
exhalation gas flow from the patient through the exhalation inlet
to the exhalation outlet 256 disposed in the liquid between the
inverted container wall and the outer container wall.
[0061] The inner cylinder 206 is sensed to be at the preset minimum
height. When running in non-conditioning mode, the breathing gas
supply source, an air pump 221 in this case, energizes and delivers
air via the bubbler bypass valve 230 in an open position with most
of the gas arriving via the tube 222 terminating at the inhalation
inlet (which now serves as the non-conditioning gas supply outlet
224) disposed inside the inner cylinder in the inverted cylinder
space 210 above the water bath's free surface 212, causing the
inner cylinder 206 to begin to rise. The inhalation valve 240 is
closed. The tube 222 serves as an inhalation line with gas flowing
out of the inverted cylinder space 210 and, in the non-conditioning
mode, a gas supply line with gas flowing into the inverted cylinder
space 210. Meanwhile, the patient is free to exhale into the water
bath via the exhalation line 252 with the exhalation outlet end 256
terminating at the preset depth based on the prescribed positive
end-expiratory pressure (PEEP).
[0062] FIG. 2F shows the ICHV apparatus in a
charging-and-expiration process from State 2 to State 1 in the
non-conditioning mode. The air pump 221 continues to deliver air
via the bubbler bypass valve 240 until the inner cylinder 206 has
risen again at the constant pressure to the preset height based on
the prescribed tidal volume to be delivered. The patient is still
free to exhale into the water bath 204 via the exhalation line 252
with the exhalation outlet 256 terminating at the preset depth
based on the prescribed PEEP. The patient exhales via the
exhalation line 252 against the hydrostatic pressure prescribed by
the PEEP tube terminal depth of the exhalation outlet 256 submerged
in the water bath 204. The exhalation bubbles rise in the annular
space 258 around the inverted inner cylinder 206. Humidity in the
exhaled breath is reabsorbed into the water bath 204. The gas
supply 221 flows breathing gas to the inverted cylinder space 210.
The breathing gas causes the inverted cylinder 206 to rise at
constant pressure again. The inner cylinder 206 charges during
expiratory gesture.
[0063] FIG. 2G shows the ICHV apparatus in the ready-to-deliver
State 1. The inner cylinder 206 again achieves its maximum height
and the air source 221 de-energizes. The inner cylinder 206 again
(similar to FIG. 2C) achieves its maximum height or elevation and
the air source de-energizes (e.g., by turning off the air pump
221). Tidal volume is added and then breathing gas delivery to the
patient is ready to begin as the patient concludes the expiratory
gesture. When a breath is sensed as being demanded (on-demand
breathing) or a second preset timing or time limit is reached
(mandatory breathing), the inhalation valve 240 separating the
trapped breathing gas supply 210 from the patient opens, allowing
the gas to escape directly to the patient. The exhalation valve 250
for the PEEP tube 252 closes at the same time.
[0064] FIG. 2H shows the ICHV apparatus in a breath-delivery
process from State 1 to State 2. Similar to FIG. 2D, the inner
cylinder 206 continues to sink lower as gas is conveyed to the
patient at the pressure indicated by the vertical disparity between
the water bath's lower free surface 212 within the inner cylinder
206 and upper free surface 244 of the outer cylinder 202. When the
inner cylinder 206 reaches its minimum height, the process
recycles.
[0065] FIG. 3A shows an example of a breath demand mode water
switch for switching on and off of the inhalation valve 240 in the
patient breathing line 260 for on-demand breathing instead of
mandatory breathing. It uses a non-toxic electrolytic liquid (e.g.,
saltwater) 314 in a manometer 310 connected to the patient
breathing line 260 (or the inhalation tube or patient supply tube
222 if the exhalation line 252 is completely separate from the
inhalation line 222 without merging) to complete the circuit of an
electrical sensor (with sensor line 330 and sensing wire 340 as
described below) when a patient begins to inhale. The manometer 310
is disposed between the inhalation valve 240 and the inhalation
outlet 266 connected to the patient. The (small) partial vacuum
caused by the initial inspiratory gesture closes the circuit
between the energized terminal and sensor terminal, which tells the
microcontroller to open the inhalation valve 240 to pressurize the
patient breathing line 260 with breathing gas. The switch is
reliable and easy to fabricate. It also provides secondary
protection against over-pressurization of the patient breathing
line 260 by setting the manometer open end 320 at some prescribed
height.
[0066] In the neutral state as illustrated in FIG. 3A, an insulated
sensing wire 340 terminates with an electrically uninsulated
terminal 342 slightly above the free surface of an electrolytic
solution 314 trapped in the U-manometer 310. Another wire, sensor
line 330 at a defined reference voltage, terminates with its
electrically uninsulated end 332 submerged in the solution 314. The
electrical circuit is broken as long as the electrolytic solution
314 is not in contact with both terminals 332, 342 simultaneously.
The inspiratory valve 240 separating the patient from the trapped
breathing gas supply 210 is closed. The normally grounded sensor
line 330 communicates with the inhalation valve 240 via the
microcontroller and relay. When no breath is demanded, the circuit
is broken and the demand signal is negative (LOW). The sensor line
330 extends from the inhalation valve 240 to the electrically
uninsulated end 332 at the bottom of the electrolytic solution
manometer tubing 310. A low-voltage (e.g., 5 VDC) signal source is
coupled to the sensing wire 340 which terminates with the
electrically uninsulated terminal 342 just above the electrolytic
solution free surface when the system is in the neutral position.
The live end 342 of the circuit is exposed but not in contact with
the electrolytic solution when no breath is demanded. The height of
the open end 320 of the electrolytic solution tube 310 provides a
secondary safety feature preventing overpressure delivery.
[0067] In the active state as illustrated in FIG. 3B, the sensor
line 330 communicates with the inhalation valve 240 via the
microcontroller and relay. When a slight drop in pressure occurs
due to the onset of a breath demand by an inhaling patient, the
solution 314 within the manometer 310 shifts toward the exposed
sensing wire's bare terminal 342 and the breath demand signal is
positive (HIGH). A momentary suction subsides when the inhalation
valve 240 opens and pressurizes the breathing line 260 to the
patient. The live end 342 of the circuit is now exposed to the
electrolytic solution 314 when a breath is demanded causing a
partial vacuum 350 in the manometer 310, causing the liquid 314 to
migrate upward via the partial vacuum 350. When the solution 314
rises enough to submerge both terminals 332, 342, the electrical
circuit is completed and the controller senses a demand signal. The
controller responds by opening the inspiratory valve 240 and
closing the expiratory (PEEP) valve (250 in FIGS. 3A-3H).
ICHV Process
[0068] FIG. 4 is a flow diagram summarizing the process 400 of
operating the ICHV apparatus of FIGS. 2A-2H. The apparatus is in
the startup state shown in FIG. 2A and described above. The minimum
elevation sensor registers that the inner cylinder 206 is at the
minimum elevation. In the preparation step 404 prior to charging,
the inhalation valve 240 is closed and the exhalation valve 250 is
opened. Next, the user or operator specifies (manually or via the
controller) whether charging will include bubbles (step 408). If
bubbles are included in the bubble-conditioning mode, the charging
step 412 closes the bubbler bypass valve 230 and starts the air
pump 221. The breathing gas supply flow is directed into the gas
volume of the inverted cylinder space 210 via the bubbler 234 to
achieve the target hydrostatic delivery pressure in the gas volume
and lift the elevation of the inner cylinder 206. If bubbles are
not included in the non-conditioning mode, the charging step 414
opens the bubbler bypass valve 230 and starts the air pump 221 to
direct breathing gas into the gas volume of the inverted cylinder
space 210 via the non-conditioning gas supply line 222.
[0069] In ready-to-deliver step 420, upon detection that the inner
cylinder 206 has reached a preset maximum elevation (e.g., by the
maximum volume proximity sensor or maximum elevation sensor), the
breathing gas supply flow into the gas volume is closed (e.g., by
deenergizing the air pump 221). If the bubbler bypass valve 230 was
opened (in the non-conditioning mode), it is now closed. Next the
operator specifies (manually or via the controller) whether the
delivery mode is mandatory or on-demand (step 424).
[0070] For mandatory delivery, the next step 430 is to determine
whether the first prescribed or preset timing has been reached. If
not, the system waits until the first preset timing is reached
(step 432). When the first preset timing is reached, a
breath-delivery step 440 opens the inhalation line 222 (e.g., by
opening the inhalation valve 240) to flow breathing gas from the
gas volume in the inverted cylinder space 210 to the patient at the
target hydrostatic delivery pressure, lowering the elevation of the
inner cylinder 206 due to lost buoyancy resulting in sinkage. The
exhalation valve 250 for the PEEP tube 252 closes at the same
time.
[0071] For on-demand delivery, the next step 450 is to determine
whether there is patient breath demand. Upon detection of a patient
breath demand signal, for instance, by a breath demand pressure or
vacuum sensor (e.g., manometer 270), the breath-delivery step 440
opens the inhalation line 222 to flow breathing gas to the patient
and closing the exhalation valve 250.
[0072] The process returns to step 404, which is now a
charging-and-expiration step, upon detection that the inner
cylinder has reached a preset minimum elevation (breath delivered,
e.g., by the minimum volume proximity sensor). The inhalation valve
240 is closed and the exhalation valve 250 is opened.
ICHV Apparatus--Additional Features and Other Embodiments
[0073] FIG. 5 is a schematic view illustrating an example of
proximity sensors in an ICHV apparatus. The proximity sensors 500
include a conductive layer 502 attached to the closed top of the
inverted inner cylinder 506 (e.g., by adhesion). A reference
voltage line 510 is disposed at an upper elevation and a lower
elevation. An upper sensing wire 520 is disposed at the upper
elevation (which represents the maximum volume proximity) and a
lower sensing wire 530 is disposed at the lower elevation (which
represents the minimum volume proximity). The reference voltage
line 510, upper sensing wire 520 and the lower sensing wire 530 are
connected to a controller 540.
[0074] The maximum volume proximity sensor or maximum elevation
sensor is formed by an exposed disconnected terminal of the
reference voltage line 510 and an exposed disconnected terminal of
the upper sensing wire 520 at the upper elevation. When the
conductive layer 502 attached to the inner cylinder 506
simultaneously contacts both terminals, the upper sensing wire 520
adopts the reference voltage and the controller 540 sense the
cylinder's location at the maximum volume proximity level.
[0075] The minimum volume proximity sensor or minimum elevation
sensor is formed by an exposed disconnected terminal of the
reference voltage line 510 and an exposed disconnected terminal of
the lower sensing wire 530 at the lower elevation. When the
conductive layer 502 attached to the inner cylinder 506
simultaneously contacts both terminals, the lower sensing wire 530
adopts the reference voltage and the controller 540 senses the
cylinder's location at the minimum volume proximity level.
[0076] FIG. 6 is a schematic view illustrating another example of a
proximity sensor in an ICHV apparatus. An ultrasonic ranging sensor
610 is positioned directly above and pointed toward the closed top
of the inverted inner cylinder 606 to serve as the proximity
sensor. The ultrasonic sensor 610 is coupled to a controller 620.
Other embodiments include magnetic reed switches or an optical
ranging sensor positioned directly above and pointed toward the
closed top of the inner cylinder 606.
[0077] FIG. 7 is a schematic view illustrating an example of a
heater and a UV light in an ICHV apparatus. A heating element 710
such as a thermostatic heater or an electric resistance heater is
provided inside the outer upright cylinder 702, to heat the water
bath 704 in which the inner inverted cylinder 706 is partially
submerged, to compensate for the absence of biologically available
heating via sinus cavities. An ultraviolet (UV) light 720 is
provided inside the upright cylinder 702 to perform virus
decontamination and prevent algal and bacterial growth. In other
embodiments, the heating element and/or UV light may be disposed
outside the water bath 704. In some embodiments, the UV light kills
pathogens; alternatively, increased salinity in the water bath can
be used.
[0078] FIG. 8 schematically illustrates an ICHV apparatus according
to another embodiment. The ICHV apparatus 800 is similar to the
ICHV apparatus 200 of FIGS. 2A-2H, including the following similar
components: an upright outer cylinder 802 containing a water bath
804, an inverted inner cylinder 806 having a closed top 808, a gas
volume in an inverted cylinder space 810 trapped by the water bath
804 in the upright cylinder 802 above an inverted inner cylinder
free water surface 812, a gas supply line or tube 820, a bubbler
bypass valve (one-way) 830 provided on a bubbler bypass line or
tube 832, a bubbler 834, an inhalation or inspiratory valve or
patient gas delivery valve (one-way) 840 provided on a patient
supply (or patient gas delivery) or inhalation line or tube 822 to
supply breathing gas, an exhalation or expiratory valve (one-way)
850 provided on an exhalation line or tube 852 to permit exhaled
breath of the patient to flow, in an opened position, from an
exhalation inlet coupled to the patient (e.g., via a mask) to an
exhalation outlet 856 in the water bath 804 of the upright cylinder
802, an annular region 858 between the upright cylinder 802 and the
inverted cylinder 806. The inhalation line 822 and the exhalation
line 852 merge at a junction 862 into a single patient breathing
line 860 coupled to the patient. Disposed between the junction 862
and the exhalation valve 850 is a manometer 870 containing a
non-toxic electrolytic liquid 874. The single patient breathing
line 260 leads to a breathing line opening 866 coupled to the
patient, which is the inhalation outlet during inhalation by the
patient and the exhalation inlet during exhalation by the patient.
The inner cylinder's free surface 812 will always be lower than the
outer cylinder's free surface 844 (the height difference
corresponds to the hydrostatic delivery pressure).
[0079] The main difference between the ICHV apparatus 200 of FIGS.
2A-2H and the ICHV apparatus 800 of FIG. 8 is the presence of a gas
supply valve 880 in the gas supply line 820 and the absence of the
air pump 221 in the ICHV apparatus 800. As such, instead of
controlling the gas supply flow by controlling the air pump 221 in
the ICHV apparatus 200, the ICHV apparatus 800 controls the gas
supply flow by controlling the gas supply valve 880, which may also
be a solenoid valve. Other than this specific feature, the
operation of the ICHV apparatus 800 is substantially identical to
the operation of the ICHV apparatus 200.
[0080] FIG. 9 schematically illustrates an ICHV apparatus according
to another embodiment. The ICHV apparatus 900 has many features
that are similar to those in the ICHV apparatus 800 of FIG. 8,
including the following similar components: an upright outer
cylinder 902 containing a water bath 904, an inverted inner
cylinder 906 having a closed top 908, a gas volume in an inverted
cylinder space 910 trapped by the water bath 904 in the upright
cylinder 902 above an inverted inner cylinder free water surface
912, a gas supply line or tube 920 leading to a bubbler 934
disposed in the water bath 904, a gas supply valve (one-way) 980
provided on the gas supply line 920, an inhalation or inspiratory
valve or patient gas delivery valve (one-way) 940 provided on a
patient supply (or patient gas delivery) or inhalation line or tube
922 to supply breathing gas, an exhalation or expiratory valve
(one-way) 950 provided on an exhalation line or tube 952 to permit
exhaled breath of the patient to flow, in an opened position, from
an exhalation inlet coupled to the patient (e.g., via a mask) to an
exhalation outlet 956 in the water bath 904 of the upright cylinder
902, an annular region 958 between the outer container wall of the
upright cylinder 902 and the inner container wall of the inverted
cylinder 906. Disposed in the inhalation line 922 downstream of the
inhalation valve 940 (between the inhalation valve 940 and the
patient) is a manometer 970 containing a non-toxic electrolytic
liquid 974. The inner cylinder's free surface 912 will always be
lower than the outer cylinder's free surface 944 (the height
difference corresponds to the hydrostatic delivery pressure).
[0081] The main difference between the ICHV apparatus 900 of FIG. 9
and the ICHV apparatus 800 of FIG. 8 is that the inhalation line
922 and the exhalation line 952 do not merge into a single patient
breathing line coupled to the patient but remain separate and are
separately coupled to the patient. Furthermore, the ICHV apparatus
900 does not include a bubbler bypass valve 830 provided on a
bubbler bypass line 832 as provided in the ICHV apparatus 800.
[0082] The operation of the ICHV apparatus 900 is substantially
identical to the operation of the ICHV apparatus 800. It is simpler
because the ICHV 900 does not have to operate the absent bubbler
bypass valve 830 in the bubbler bypass line 832 of the ICHV
apparatus 800. The opening and closing of the inhalation valve 940
in the inhalation line 922 and the exhalation valve 950 in the
exhalation line 952 are similar to the opening and closing of the
inhalation valve 840 in the inhalation line 822 and the exhalation
valve 850 in the exhalation line 852. Because the inhalation line
922 and the exhalation line 952 do not merge into a single patient
breathing line (in which there is two-way air flow), there may be
less restrictions or requirements on the operation of the
inhalation valve 940 and the exhalation valve 950 and coordination
of the operation in the separate inhalation line 922 and exhalation
line 952 (in which there is one-way air flow in each). This
separation of flows also avoids "dead air" residing and oscillating
in the tubing between the ICHV and patient. In a single tube
design, the potential exists for residual quantities of exhaled gas
from a previous breath to remain in the tube only to be fed back to
the patient in the initial stage of new breath delivery.
[0083] FIG. 10 shows an example of an evaporation and
humidification inhibitor for a PEEP tube 1010. If long-term use of
the non-conditioning mode is intended, a thin layer of non-toxic
oil with low volatility and specific gravity less than one, such as
partially-hydrogenated vegetable oil or food-grade mineral oil, may
be employed as an evaporation and humidification inhibitor 1020
over a water reservoir. The oil blanket can be located on the water
free surface (212 in FIG. 2A) within the inner cylinder (to
minimize humidification), the water free surface of (244 in FIG.
2A) the outer cylinder (to minimize evaporation to the ambient
environment), or both free surfaces. The PEEP tube 1010 terminates
in its own separate sterilization reservoir with permeable membrane
shown near the top of the free surface or a hydraulically separate
PEEP reservoir to reduce PEEP variability during operation and to
possibly aid in exhaled air sterilization.
[0084] FIG. 11 shows an example of a smaller reservoir 1140 of
water 1150 treated with a sterilizing agent (dissolved biocidal
chemical or UV-C irradiation, for example) located either outside
or, space permitting, inside the outer cylinder 802, but
hydraulically separated from the main water bath 804, for housing
the reentrant PEEP tube terminus 856. A permeable membrane, such as
woven cotton, located below the surface of this PEEP bath 1150 may
help break apart the large exhalation bubbles, mitigating
sterilization further by increasing residency time and gas surface
area. Another advantage to this arrangement is a more-consistent
water level reducing the PEEP value's operationally unintended
variability during inner cylinder 806 movement; adjustability by
the user is still maintained. An evaporation and humidification
inhibitor 1160 (e.g., oil blanket) is located on the water free
surface 812 within the inner cylinder (to minimize humidification)
and the water free surface 844 of the outer cylinder (to minimize
evaporation to the ambient environment). The ICHV apparatus 800B of
FIG. 11 is a modified version of the ICHV apparatus 800 of FIG. 8
with like reference characters for like parts.
[0085] The apparatus may be thought of as having means for
directing a breathing gas to the inverted container space, to move
the inverted container upward from a preset minimum elevation
position when the breathing gas in the inverted container space
reaches a hydrostatic delivery pressure, to continue moving the
inverted container upward at the hydrostatic delivery pressure
while a volume of the inverted container space increases at the
hydrostatic delivery pressure, to stop moving the inverted
container upward when the inverted container reaches a preset
maximum elevation position, and to move the inverted container
upward at the hydrostatic delivery pressure when the inverted
container drops from the preset maximum elevation position to the
preset minimum elevation position. In one example, such means may
include the gas supply line 220, air pump 221, bubbler bypass valve
230, and inhalation valve 240. The means may further include the
manometer 310 (having the electrolytic liquid 314 and connected to
the patient breathing line 260 or the inhalation line 222) and the
sensing wire 340, and/or may further include proximity sensor 500,
reference voltage line 510, and upper sensing wire 520, and/or may
further include the ultrasonic ranging sensor 610, and/or may
further include the controller 130, 540, and/or 620. In another
example, the means may include the gas supply line 820, bubbler
bypass valve 830, bubbler bypass line 832, and inhalation valve
840. The means may further include the manometer 870 and/or may
further include the proximity sensor 500, reference voltage line
510, upper sensing wire 520, and lower sensing wire 530, and/or may
further include the ultrasonic ranging sensor 610, and/or may
further include the controller 130, 540, and/or 620. In another
example, the means may include the gas supply line 920, inhalation
valve 940, and gas supply valve 980. The means may further include
the manometer 970, and/or may further include the proximity sensor
500, reference voltage line 510, upper sensing wire 520, and lower
sensing wire 530, and/or may further include the ultrasonic ranging
sensor 610, and/or may further include the controller 130, 540,
and/or 620.
[0086] The apparatus may also be thought of as having means for
directing an exhalation gas flow, when the inverted container has
reached the preset minimum elevation position, to permit the
exhalation gas flow from the patient through the exhalation inlet
to the exhalation outlet disposed in the liquid between the
inverted container wall and the outer container wall, and, based on
one of (1) detection of the target hydrostatic backpressure at the
exhalation outlet or (2) a second preset timing, to stop the
exhalation gas flow from the exhalation inlet to the exhalation
outlet in the liquid at the fixed elevation. In one example, such
means may include the exhalation valve 250 or 850 or 950. The means
may further include the proximity sensor 500, reference voltage
line 510, and lower sensing wire 530, and/or may further include
the ultrasonic ranging sensor 610, and/or may further include the
controller 130, 540, and/or 620.
ICHV Apparatus Characteristics
[0087] The ICHV apparatus may have different configurations with
different characteristics including available tidal volume,
delivery pressure, operational mass, and various dimensions. The
various components can be custom-made using a variety of materials
and processes or commercially available, at different price ranges.
The present invention can be implemented based on various
operational needs and budget constraints.
[0088] If less pressure and/or tidal volume is needed, it can be
easily modified to suit the providers' needs with regard to tidal
volume and delivery pressure or even modularized via optional
extensions to make it taller (taller=greater capacity for pressure
and volume).
[0089] FIG. 12 shows a graph of available tidal volume, added mass,
and maximum unit height versus delivery pressure of the baseline
ICHV apparatus of FIG. 8. The added mass refers to the adjustable
cylinder weights added to the inverted cylinder 606, for example,
by placing them on top of the closed top 608 of the inverted
cylinder 606. The dimensions of breadth-width-height (BWH) are as
follows: BWH.sub.min of 12.4 cm.times.12.4 cm.times.57.9 cm
(shipping dimension) and BWH.sub.max of 12.4 cm.times.12.4
cm.times.104.4 cm (when delivering max. tidal volume at min.
pressure).
[0090] The operational mass is about 10 to 12 kg (water+cylinder
weight=7.73 kg plus structure/valves/tubes). The operational water
volume needed is 2.66 L when delivering maximum pressure (min.
tidal volume) and is 7.73 L when delivering maximum tidal volume
(min. delivery pressure).
[0091] The available tidal volume has an inverse relationship with
the delivery pressure. The available PEEP range is 0 to 53
cmH.sub.2O if the PEEP tube terminates in the main reservoir. The
available tidal volume range (example setpoints; pressure &
volume are analog adjustments) is 0 to 1,070 mL when delivered at
40 cmH.sub.2O, is 0 to 3,070 mL when delivered at 20 cmH.sub.2O, is
0 to 3,570 mL when delivered at 15 cmH.sub.2O, is 0 to 4,070 mL
when delivered at 10 cmH.sub.2O, and is 0 to 4,570 mL when
delivered at 5 cmH.sub.2O.
Patient Ventilator Mask
[0092] In one example, the ventilator mask 120 of FIG. 1 is an
existing mask modified to replace filters with valves. The mask may
be connected to an inhalation line having an inhalation valve and
an exhalation line having an exhalation valve. It can maintain a
net positive pressure in the plenum between the mask and the
patient's nose and mouth. It allows low-pressure breathing air to
enter the plenum as dictated either by a controller (e.g.,
mandatory breathing operation) or by cues from the patient (e.g.,
on-demand breathing operation). It allows air to be exhaled through
a separate valve, either by the predetermined control schedule
(e.g., mandatory breathing) or by cues from the patient (e.g.,
on-demand breathing). It allows the patient to inhale and exhale
freely in the event of a control failure or external valve system
failure.
[0093] In one embodiment, a commercially available mask is modified
to have the above features. The mask has attached filters. In its
respirator mode, the user inhales air through the filters and
exhales air through a central valve. Alternate or new filters can
be purchased and reinstalled.
[0094] In the modified ventilator mask, one of the inlet non-return
valves is defeated by removing the flapper valve from inside the
mask. This now becomes the exhale port and is opened and closed by
a downstream solenoid valve and then vented, through an appropriate
filter to the atmosphere. The original exhale valve is reversed by
taking flapper valve from outside of the mask and re-fitting inside
the mask. This valve now acts as an emergency inhale port in case
of failure of the remaining inlet valve (e.g., a solenoid upstream
of the respirator stays closed due to some failure). In normal
operation, the positive pressure maintained in the plenum between
the mask and the user's face keeps this emergency valve closed. The
remaining inhale valve is left untouched. The two original filters
of the respirator are removed and replaced by two ventilator valve
adaptors.
[0095] To allow air tubes to be connected to the mask, an adapter
connection is made using the pair of ventilator valve adaptors
having proximal portions attached to the two original inhale ports.
The ventilator valve adaptors have distal portions to be attached,
via an inhalation port to an inhalation line having an inhalation
valve and via an exhalation port to an exhalation gas line having
an exhalation valve.
[0096] The manufacturing of the mask may involve printing PETG and
more flexible materials, as well as PETG, PET, PLA, and ABS. The
manufacturing process uses Ecoflex 0035 for the silicone mold and
Task 8 resin for the mask. Another process uses Wiles April 12
version with Cheetah TPU. Yet another process is used to make a
bunch of PLA's at 0.15 mm layer height, about 10 ABS, 6 or so PETG
at 30% and about as many at 40, a few ABS at 30% infill and about
as many 40%.
Controller
[0097] FIG. 13 illustrates an example of a controller or computing
system 2300 including logic. The computing system 2300 includes a
processing system 2310 having a hardware processor 2325 configured
to perform a predefined set of basic operations 2330 by loading
corresponding ones of a predefined native instruction set of codes
2335 as stored in the memory 2315. The computing system 2300
further includes input/output 2320 having user interface 2350,
display unit 2355, communication unit 2360, and storage 2365.
[0098] The memory 2315 is accessible to the processing system 2310
via the bus 2370. The memory 2315 includes the predefined native
instruction set of codes 2335, which constitute a set of
instructions 2340 selectable for execution by the hardware
processor 2325. In an embodiment, the set of instructions 2340
include logic 2345 to perform the functions of the ICHV apparatus
as described above, including those summarized in the flow diagrams
of FIG. 4.
[0099] The various logic 2345 is stored in the memory 2315 and
comprises instructions 2340 selected from the predefined native
instruction set of codes 2335 of the hardware processor 2325,
adapted to operate with the processing system 2310 to implement the
process or processes of the corresponding logic 2345.
[0100] In specific embodiments, the controller includes an Arduino
controller and breadboard, several resistors and LEDs, a voltage
regulator, and a potentiometer. These control system components are
assembled and placed in a housing.
[0101] FIGS. 14A-14G show an example of controller logic for
operating an ICHV system according to an embodiment of the
invention. It is noted that this example of the controller logic
does not include the breath timing function. An additional feature
that can be added is to provide a user setting specifying the
mandatory breath frequency in terms of breaths-per-minute.
[0102] The inventive concepts taught by way of the examples
discussed above are amenable to modification, rearrangement, and
embodiment in several ways. For example, the embodiments shown
employ an inverted inner cylindrical container and an upright outer
cylindrical container, each having a uniform cross-section. In
other embodiments, the inverted inner container or the upright
outer container or both may be non-cylindrical with nonuniform
cross-sections and/or nonuniform cross-sectional areas along the
height direction, or may be non-cylindrical with a uniform
cross-sectional area. The calculations of volumes, pressures, and
heights will be different as a result, but the apparatus operates
on the same principles.
[0103] Some embodiments of the ICHV system present low-tech,
easy-to-fabricate arrangements to provide breathing gas to a
patient's mask. The required inputs include: 1) compressed
breathing gas supply, 2) electricity for microcontroller, UV light,
and heating element, and 3) distilled water. If only ambient air is
available (i.e., no compressed breathing gas supply is available to
supply breathing gas into a gas volume of the inverted cylinder
space), a linear drive unit can be used to lift the inverted
cylinder and a one-way valve is provided to allow atmospheric air
to enter into the gas volume of the inverted cylinder space.
[0104] Accordingly, although the present disclosure has been
described with reference to specific embodiments and examples,
persons skilled in the art will recognize that changes may be made
in form and detail without departing from the spirit and scope of
the disclosure.
[0105] Certain attributes, functions, steps of methods, or
sub-steps of methods described herein may be associated with
physical structures or components, such as a module of a physical
device that, in implementations in accordance with this disclosure,
make use of instructions (e.g., computer executable instructions)
that are embodied in hardware, such as an application specific
integrated circuit, computer-readable instructions that cause a
computer (e.g., a general-purpose computer) executing the
instructions to have defined characteristics, a combination of
hardware and software such as processor implementing firmware,
software, and so forth so as to function as a special purpose
computer with the ascribed characteristics. For example, in
embodiments a module may comprise a functional hardware unit (such
as a self-contained hardware or software or a combination thereof)
designed to interface the other components of a system such as
through use of an API. In embodiments, a module is structured to
perform a function or set of functions, such as in accordance with
a described algorithm. This disclosure may use nomenclature that
associates a component or module with a function, purpose, step, or
sub-step to identify the corresponding structure which, in
instances, includes hardware and/or software that function for a
specific purpose. For any computer-implemented embodiment, "means
plus function" elements will use the term "means;" the terms
"logic" and "module" and the like have the meaning ascribed to them
above, if any, and are not to be construed as means.
[0106] The claims define the invention and form part of the
specification. Limitations from the written description are not to
be read into the claims.
[0107] An interpretation under 35 U.S.C. .sctn. 112(f) is desired
only where this description and/or the claims use specific
terminology historically recognized to invoke the benefit of
interpretation, such as "means," and the structure corresponding to
a recited function, to include the equivalents thereof, as
permitted to the fullest extent of the law and this written
description, may include the disclosure, the accompanying claims,
and the drawings, as they would be understood by one of skill in
the art.
[0108] To the extent the subject matter has been described in
language specific to structural features and/or methodological
steps, it is to be understood that the subject matter defined in
the appended claims is not necessarily limited to the specific
features or steps described. Rather, the specific features and
steps are disclosed as example forms of implementing the claimed
subject matter. To the extent headings are used, they are provided
for the convenience of the reader and are not be taken as limiting
or restricting the systems, techniques, approaches, methods,
devices to those appearing in any section. Rather, the teachings
and disclosures herein can be combined, rearranged, with other
portions of this disclosure and the knowledge of one of ordinary
skill in the art. It is the intention of this disclosure to
encompass and include such variation. The indication of any
elements or steps as "optional" does not indicate that all other or
any other elements or steps are mandatory.
* * * * *