U.S. patent application number 17/361958 was filed with the patent office on 2022-02-24 for high flow therapy with built-in oxygen concentrator.
The applicant listed for this patent is Vapotherm, Inc.. Invention is credited to Charles Busey, Felino V. Cortez, JR., George C. Dungan, II.
Application Number | 20220054791 17/361958 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-24 |
United States Patent
Application |
20220054791 |
Kind Code |
A1 |
Cortez, JR.; Felino V. ; et
al. |
February 24, 2022 |
HIGH FLOW THERAPY WITH BUILT-IN OXYGEN CONCENTRATOR
Abstract
Apparatus and methods for delivering a heated and humidified
mixture of oxygen and air are provided. The apparatus includes an
air compressor and oxygen concentrator enclosed in the housing of a
vapor transfer system. The air compressor supplies air at a first
pressure to a gas inlet. The oxygen concentrator provides oxygen at
a second pressure to the gas inlet. The oxygen concentrator and the
air compressor are in fluid communication and are configured such
that the first pressure of the compressed air and the second
pressure of the oxygen are about equal. The apparatus includes a
vapor transfer system having a gas passage, a liquid passage having
heated liquid and vapor, and a membrane that separates the gas
passage and liquid passage. The membrane is positioned to transfer
vapor from the liquid passage to the gas passage.
Inventors: |
Cortez, JR.; Felino V.;
(Bowie, MD) ; Busey; Charles; (Easton, MD)
; Dungan, II; George C.; (Dallas, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vapotherm, Inc. |
Exeter |
NH |
US |
|
|
Appl. No.: |
17/361958 |
Filed: |
June 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15251185 |
Aug 30, 2016 |
11077279 |
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17361958 |
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62212365 |
Aug 31, 2015 |
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International
Class: |
A61M 16/16 20060101
A61M016/16; A61M 16/10 20060101 A61M016/10; A61M 16/00 20060101
A61M016/00; A61M 16/06 20060101 A61M016/06; A61M 16/12 20060101
A61M016/12 |
Claims
1-20. (canceled)
21. A method for achieving a heated and humidified air-oxygen
mixture for delivery to a patient, the method comprising: passing
air from an air compressor at a first pressure to the gas inlet;
passing oxygen from an oxygen concentrator at a second pressure to
the gas inlet; mixing the air and the oxygen at the gas inlet,
wherein the first pressure and the second pressure are about equal;
and passing the mixed air and oxygen through a vapor transfer
system.
22. The method of claim 21, wherein the first pressure and the
second pressure are about equal within 10%.
23. The method of claim 21, wherein the first pressure and the
second pressure are about equal within 5%.
24. The method of claim 21, wherein the first pressure and the
second pressure are about 6-11 psi.
25. The method of claim 21, wherein passing the mixed air and
oxygen through a vapor transfer system further comprising heating
and humidifying the mixed air and oxygen.
26. The method of claim 25, further comprising: passing the heated
and humidified mixed air and oxygen through a gas outlet to a first
elongated lumen and a second elongated lumen, wherein the first
elongated lumen is coupled to a first end of a nasal cannula and
the second elongated lumen is coupled to a second end of a nasal
cannula, wherein a first flow of gas from the first elongated lumen
and a second flow of gas from the second elongated lumen are
directed through a first and second nasal prong.
27. The method of claim 26, wherein the first flow of gas through
the first elongated lumen and the second flow of gas through the
second elongated lumen are not in fluid communication throughout
the nasal cannula.
28. The method of claim 26, wherein the first flow of gas through
the first elongated lumen and the second flow of gas through the
second elongated lumen are in fluid communication at the first and
second nasal prong.
29. The method of claim 26, wherein the nasal cannula defines a
constant diameter flow path.
30. The method of claim 26, wherein an inner diameter of the first
elongated lumen and an inner diameter of the second elongated lumen
are about equal to 1/4''.
31. The method of claim 26, wherein the flow rate through the first
elongated lumen and the second elongated lumen is 40 lpm or
greater.
32. The method of claim 26, wherein the first elongated lumen and
the second elongated lumen each has a length of about 1.8 meters
and wherein the first elongated lumen and the second elongated
lumen each provides a gas from the gas outlet at a range of flow
rates of about 5-40 lpm.
33. The method of claim 26, wherein the first elongated lumen and
the second elongated lumen each has a length of about 10 m.
34. The method of claim 33, wherein the first elongated lumen and
the second elongated lumen provide a gas from the gas outlet at a
range of flow rates of about 0.25-10 lpm.
35. The method of claim 26, wherein the first and second flow of
gas maintain a temperature within +/-5 degrees Celsius from a set
temperature across a range of flow rates from 5 lpm to 40 lpm.
36. The method of claim 26, wherein the heated and humidified mixed
air and oxygen exits the gas outlet with a humidity within the
range of 26-56 mg/L.
37. The method of claim 21, wherein the vapor transfer system
further has a membrane which is comprised of a plurality of hollow
fiber tubes.
38. The method of claim 21, wherein the vapor transfer system
further has a gas passage and a liquid passage, wherein the gas
passage is enveloped by the liquid passage.
39. The method of claim 21, wherein the vapor transfer system
further has a gas passage and a liquid passage, wherein the liquid
passage is enveloped by the gas passage.
40. The method of claim 21, wherein the apparatus operates at a
sound level of about 55 dB or lower.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/212,365, filed on Aug. 31, 2015, which is hereby
incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to systems for providing
respiratory therapies. More specifically, the present disclosure
relates to a system which provides heated and humidified oxygen and
air mixtures.
BACKGROUND
[0003] Patients with respiratory ailments may be treated with
respiratory assist devices that deliver supplemental breathing gas.
Such devices may deliver gas to a patient using high flow therapy
("HFT"). During HFT therapy, breathing gas with a high flow rate is
delivered to a patient via a nasal cannula in order to increase a
patient's fraction of inspired oxygen (FiO2) while decreasing a
patient's work of breathing. In some implementations, HFT devices
heat and humidify the delivered breathing gas to reduce patient
discomfort.
[0004] Patients with respiratory ailments may also benefit from
oxygen therapy. During administration of oxygen therapy, oxygen, or
breathing gas including oxygen, is delivered to the patient. While
HFT and oxygen therapy have similarities, patients receiving HFT
and oxygen therapy must receive one therapy at a time due to
differing device requirements. By applying the therapies
individually, the amount of the patient's time consumed by therapy
is increased, inevitably increasing the discomfort a patient
experiences during therapy and preventing the patient from enjoying
other activities.
[0005] Further burdening patients is the lack of adequate at-home
HFT therapies as patients with respiratory ailments may find
high-pressure breathing gas unavailable in the home setting.
Instead, patients are forced to travel to clinical settings with
high-pressure breathing gas sources.
SUMMARY
[0006] Disclosed herein are systems, methods, and devices for a
self-contained apparatus capable of delivering a heated and
humidified mixture of oxygen and air to a patient in order to
overcome the aforementioned problems. Furthermore, these systems,
methods and devices allow for delivery of heated and humidified
breathing gas mixtures to a patient in a home environment,
relieving a patient from the burden of having to travel to a
clinic. This, and other advantages described below, is achieved by
incorporating a vapor transfer system with an air compressor and an
oxygen concentrator. The incorporation of an HFT system which
incorporates both a compressed air source and an economical means
of producing medical-grade oxygen allows for broad deployment of
HFT in non-clinical settings. Traditionally, oxygen concentrators
have not been used in traditional medical-grade HFT systems due to
the low pressure output of these concentrators.
[0007] The system described herein overcomes the challenges
associated with the administration of HFT in non-clinical settings
by incorporating an HFT system with an air compressor and an oxygen
concentrator which operate at low pressures. The system
incorporates these features into a single portable housing which
minimizes clutter in a non-clinical or home environment and
maximizes patient mobility around the system. The air compressor
acts as a source for pressurized air and the oxygen concentrator
provides oxygen for blending into a breathing gas mixture having an
appropriate concentration of oxygen. The oxygen and the air are
pressure-matched to facilitate mixing before being heated and
humidified for delivery to the patient. The system allows the low
pressure gas from the oxygen concentrator to blend with a low
pressure gas from an air compressor. The matched pressures allow
the system to blend the air-oxygen breathing gas having higher
concentrations of oxygen and with higher output gas flow before it
is directed to the HFT system. Following the heating and
humidifying of the gas, the system incorporates low resistance
large inner diameter tubing to allow for high gas flow of up to 40
liters per minute (lpm) to be delivered to the patient via a nasal
cannula. Use of a compressor and an oxygen concentrator to provide
gas and oxygen which is mixed, heated, and humidified allows for
administration of HFT therapies in home and other non-clinical
environments without the need for additional equipment such as
oxygen cylinders, tanks, or high-pressure sources.
[0008] Furthermore, the system provides a means for efficient
administration of HFT while maximizing patient comfort. In some
implementations, the system provides high flow of breathing gas
through tubing with a large inner diameter delivered to a nasal
cannula with small inner diameter nasal prongs. Due to challenges
associated with the condensation of heated and humidified breathing
gas when transported through long lengths of tubing, lengths of
tubing of about 2 m are used with HFT. The system is designed for
use with a variety of cannula configurations. One such
configuration minimizes the amount of noise that reaches a patient
by maintaining fluid separation of the flows of gas to each nare
from the vapor transfer unit to the nare. Another possible
configuration of the nasal cannula includes a point of fluid
communication at the point of the administration of the gas via the
nasal prongs into the nares. Noise reduction to the patient is
further decreased by use of large diameter tubing. The system
utilizes dual low pressure compressor and concentrator systems
which further decrease device noise.
[0009] Moreover, the system is able to provide both heated and
humidified HFT and oxygen therapy delivering humidified but
non-heated breathing gas with a high concentration of oxygen to a
patient. Because the high-concentration oxygen breathing gas is not
humidified, issues of rainout and condensation present less of a
challenge and the high concentration oxygen breathing gas can be
provided to a patient through a long length of tubing, allowing
maximized patient mobility while receiving oxygen therapy. By
combining the HFT and oxygen therapy in one self-contained system,
the total amount of time consumed by administering respiratory
therapy to a patient is reduced, and the need for additional
devices in a home environment is eliminated.
[0010] In one aspect, an apparatus for delivering a heated and
humidified mixture of oxygen and air includes a vapor transfer
system that has a housing, a gas inlet, a gas outlet, a liquid
inlet, a liquid outlet, a gas passage coupling the gas inlet to the
gas outlet, a liquid passage coupling the liquid inlet to the
liquid outlet, and a membrane that separates the gas passage and
liquid passage. The membrane is positioned to transfer vapor from
the liquid passage to the gas passage. The apparatus also includes
a liquid supply coupled to the liquid inlet, and the liquid supply
also has a heater that heats liquid of the liquid supply. The
apparatus also includes an air compressor enclosed in the housing
of the vapor transfer system. The air compressor is configured to
supply air at a first pressure to the gas inlet. Additionally, the
apparatus includes an oxygen concentrator also enclosed in the
housing of the vapor transfer system. The oxygen concentrator is
configured to output oxygen at a second pressure to the gas inlet.
The oxygen concentrator and the air compressor are in fluid
communication and are configured such that the first pressure of
the compressed air and the second pressure of the oxygen are about
equal.
[0011] The pressure of the compressed air and the pressure of the
oxygen may vary. For example, in certain implementations, the first
pressure of the compressed air and the second pressure of the
oxygen are equal to within 10%. In some implementations, the first
pressure of the compressed air and the second pressure of the
oxygen are equal to within 5%. In some implementations, the first
pressure of the compressed air and the second pressure of the
oxygen are equal to about 6-11 psi.
[0012] In some implementations, the gas outlet is in fluid
communication with a first elongated lumen and a second elongated
lumen. The first elongated lumen is coupled to a first end of a
nasal cannula and the second elongated lumen is coupled to a second
end of a nasal cannula, and a first flow of gas from the first
elongated lumen and a second flow of gas from the second elongated
lumen are directed through a first and second nasal prong. In some
implementations, the first flow of gas through the first elongated
lumen and the second flow of gas through the second elongated lumen
are not in fluid communication through the nasal cannula. In some
implementations, the first flow of gas through the first elongated
lumen and the second flow of gas through the second elongated lumen
are in fluid communication at the first and second nasal prong. In
some implementations, the nasal cannula defines a constant diameter
flow path for the first and second flows of gas. In some
implementations, the inner diameter of the first elongated lumen
and the inner diameter of the second elongated lumen are about
equal to 1/4''. In some implementations, the flow rate through the
first elongated lumen and the second elongated lumen is equal to 40
lpm or greater.
[0013] In some implementations, the apparatus also includes a base
unit that releasably engages the vapor transfer unit to enable
reuse of the base unit and selective disposal of the vapor transfer
unit. The liquid passage is coupled to the base unit to provide
liquid flow between the base unit and a vapor transfer unit when
the vapor transfer unit is received by the base unit.
[0014] In some implementations, the first elongated lumen and the
second elongated lumen each has a length of about 1.8 meters and
the lumens each provide gas from the gas outlet at a flow rate of
about 5-40 (lpm). In certain implementations, the first elongated
lumen and the second elongated lumen each has a length of about 10
meters. In some implementations, the first elongated lumen and the
second elongated lumen provide a gas from the gas outlet at a range
of flow rates of about 0.25-10 lpm.
[0015] In some implementations, the first flow of gas from the
first elongated lumen and the second flow of gas from the second
elongated lumen maintain a temperature of within 5 degrees Celsius
from a set temperature across a range of flow rates from 5-40 lpm.
In some implementations, a flow of gas exits the gas outlet with a
humidity within the range of 26-56 mg/L.
[0016] In some implementations, the membrane in the vapor transfer
system comprises a plurality of hollow fiber tubes. In some
implementations, the gas passage of the vapor transfer system is
enveloped by the liquid passage. In some implementations, the
liquid passage is enveloped by the gas passage. In some
implementations, the apparatus operates at a sound level of about
55 dB or lower.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing and other objects and advantages will be
apparent upon consideration of the following detailed description,
taken in conjunction with the accompanying drawings. The skilled
artisan will understand that the drawings primarily are for
illustrative purposes and are not intended to limit the scope of
the subject matter described herein. The drawings are not
necessarily to scale; in some instances, various aspects of the
subject matter disclosed herein may be shown exaggerated or
enlarged in the drawings to facilitate an understanding of
different features. In the drawings, like reference characters
generally refer to like features (e.g., functionally similar and/or
structurally similar elements).
[0018] FIG. 1 shows a schematic representation of a system for
delivering a heated and humidified mixture of oxygen and air
according to an exemplary aspect of this invention;
[0019] FIG. 2 is a front perspective view of an exemplary
embodiment of the system;
[0020] FIG. 3 is a front perspective view of the exterior of an
exemplary embodiment of the system;
[0021] FIG. 4 is a histogram displaying temperature performance of
the system over a variety of breathing gas output flow rates with
comparison to other HFT devices;
[0022] FIG. 5 is a histogram displaying humidification performance
of the system over a variety of breathing gas output flow rates
with comparison to other HFT devices;
[0023] FIG. 6 is a graph displaying oxygen enrichment of the system
over a variety of total output flow rates with comparison to other
devices; and
[0024] FIG. 7 is an illustrative process for achieving a heated and
humidified air-oxygen mixture.
[0025] The features and advantages of the inventive concepts
disclosed herein will become more apparent from the detailed
description set forth below when taken in conjunction with the
drawings.
DETAILED DESCRIPTION
[0026] Aspects of the apparatus will now be described with
reference to the figures. Such figures are intended to be
illustrative rather than limiting and are included herewith to
facilitate the explanation of the present invention.
[0027] The systems, devices and methods described herein provide a
means for producing and delivering a heated and humidified mixture
of oxygen and air to a patient without use of external high flow
oxygen and air sources. The systems, devices, and methods described
herein provide for HFT use in a home or other non-clinical setting.
Making use of an air compressor, an oxygen concentrator and vapor
transfer system, pressurized air and concentrated oxygen may be
produced and mixed to achieve oxygen-air mixtures which are heated
and humidified for patient delivery. Matching the pressure of the
compressed air and concentrated oxygen allows for mixing of
oxygen-air blends of varying oxygen concentration at a variety of
flow rates.
[0028] FIG. 1 shows a schematic representation of a system for
delivering a heated and humidified mixture of oxygen and air. The
system 100 includes a base unit 112, a vapor transfer unit 120, an
air compressor unit 150 and an oxygen concentrator unit 160. The
base unit 112 may include controls for operating the system 100 and
for controlling the vapor transfer unit 120, air compressor unit
150 and oxygen concentrator unit 160 individually. The vapor
transfer unit 120 includes a housing 122, a gas inlet 124, a gas
outlet 125, a liquid inlet 127, a liquid outlet 128, a gas passage
126, a liquid passage 130, a membrane 132, a liquid reservoir 134,
a liquid port 136, and a heater 138. The system is configured to
draw in air 140 through an air inlet 142 in the housing 122, and to
direct the air 140 to the air inlet 154 in the air compressor unit
150 or to the air inlet 164 in the oxygen concentrator unit 160. In
some implementations there may be a single air inlet 142 in the
housing 122 which draws in air 140 and directs the air 140 to both
the air compressor unit 150 and the oxygen concentrator unit 160.
In other implementations there may be multiple air inlets 142 in
the housing 122. The air compressor unit 150 pressurizes the air
140 and expels the compressed air 152 through a compressed air
outlet 156 into a compressed air passage 158. The air is expelled
having a first pressure 159. The oxygen concentrator unit 160
concentrates the oxygen 162 from the air 140 and expels the
concentrated oxygen 162 from the oxygen concentrator unit 160
through an oxygen outlet 166 and into an oxygen passage 168. The
oxygen 162 exits the concentrator unit 160 with a second pressure
169. The first pressure 159 output from the air compressor unit 150
is matched to the second pressure 169 output from the oxygen
concentrator unit 160. The matched pressures allows the air and
oxygen to blend at a higher oxygen concentration and at high output
gas flow without one gas overcoming the other.
[0029] The compressed air passage 158 and the oxygen passage 168
meet at a junction 170 in the internal tubing where the flows are
in fluid communication. The compressed air 152 and concentrated
oxygen 162 gases are blended at the junction 170 to form an
oxygen-air breathing gas mixture 174 and continue through the gas
passage 172 to the gas inlet 124 into the vapor transfer unit 120.
In some implementations, blending of the gases (air 152 and oxygen
162) may be aided by a manifold or deflector which directs the
gases in a direction. The first pressure 159 of the compressed air
152 may be matched to the second pressure 169 of the concentrated
oxygen 162 to allow mixing at high oxygen concentrations. The first
pressure 159 and the second pressure 169 may be controlled by
controls on the base unit 112 or they may be automatically
controlled to maintain a pressure match. The first pressure 159 and
the second pressure169 may be controlled to be about 6 psi. In some
implementations the first pressure 159 and the second pressure 169
are maintained at 5-11 psi. A pressure of 5-11 psi is attainable
for a self-contained oxygen concentrator and air compressor and
does not require the use of high-pressure gas sources. These
pressures allow the system to be used in a home or non-clinical
environment with minimized noise output. The first pressure 159 may
be controlled to be equal to the second pressure 169 to within a
percentage (e.g. within 25%, 20%, 10%, 5% 3%). Closely matched
pressures avoids backflow and prevents one mixed gas from
overcoming the other during mixing. Blending gases with matched
pressures allows for the mixing of the desired concentration of
oxygen.
[0030] The vapor transfer unit 120 is configured to heat and
humidify the oxygen-air breathing gas mixture 174. The vapor
transfer unit 120 includes a gas passage 126 which connects the gas
inlet 124 to a gas outlet 125. The vapor transfer unit 120 also
includes a liquid reservoir 134 which may be filled at a liquid
port 136. Liquid may leave the liquid reservoir 134 and enter the
vapor transport unit 120 at a liquid inlet 127 connected to a
liquid outlet 128 via a liquid passage 130. The liquid reservoir
134 further includes a heater 138 which is configured to heat the
liquid and may be controlled by control on the base unit 112. The
heater 138 heats the liquid and the liquid is transported through
the liquid passage 130 to the vapor transfer unit 120 where vapor
from the heated liquid may be transferred to the oxygen-air
breathing gas mixture 174 through a membrane 132 which separates
the liquid passage 130 and the gas passage 172.
[0031] After passing through the gas passage 126 the mixture of
heated and humidified oxygen-air breathing gas mixture 174 passes
out of the housing 122 of the vapor transfer unit at a gas outlet
176. The gas outlet 176 is configured to be connected to a variety
of possible cannulas or other mechanisms for delivery of gas to a
patient.
[0032] In some implementations the vapor transfer unit 120 may be
configured to be releasably coupled to the base unit 112 such that
the vapor transfer unit 120 may be disposable while the base unit
112 may be reused. A releasable vapor transfer unit 120 may
additionally be removed for cleaning or maintenance. In such
implementations, the liquid passage 130 may be coupled to the base
unit 112 to allow liquid flow between the base unit 112 and the
vapor transfer unit 120 when the vapor transfer unit 120 is
releasably coupled to the base unit 112.
[0033] The membrane 132 of the vapor transfer unit 120 may be
comprised of a plurality of hollow fibers. Furthermore, in some
implementations the membrane 132 may separate the gas passage 126
from the liquid passage 130 such that the gas passage 126 is
enveloped by the liquid passage 130. In other implementations the
gas passage 126 and the liquid passage 130 may be arranged such
that the gas passage 126 envelopes the liquid passage 130.
[0034] The vapor transfer unit 120 is configured to heat and
humidify the oxygen-air breathing gas mixture 174 before delivery
to a patient. The temperature of the heater 138 may be controllable
by an operator using controls on the base unit 112. The temperature
range may alternatively be preset or constrained to an allowable
range of temperatures (e.g. 33-41.degree. C.). Temperatures in the
range of 33-41.degree. C. are comfortable for a patient and allow a
gas humidity to be maintained over the delivery path to a patient
with minimal condensation and rainout. The temperature control of
the oxygen-air breathing gas mixture 174 may be controllable such
that for a variety of flow rates the set temperature is maintained
within an average amount (e.g. within 2.degree. C., 5.degree. C.,
10.degree. C.). The humidity of the oxygen-air breathing gas
mixture 174 may also be controlled such that humidity of up to
90-100% at room temperature is achieved (e.g. 35-56 mg/L). In some
implementations, a humidity of about 22-56 mg/L may be
provided.
[0035] FIGS. 2 and 3 show perspective views of an exemplary
embodiment of the system. Specifically, FIG. 2 shows a front
perspective view of an exemplary embodiment of the system, while
FIG. 3 shows a front perspective view of the exterior of an
exemplary embodiment of the system. The system 200 has a compressor
portion 286 and a concentrator portion 284 which also includes the
vapor transfer system 220. The system 200 includes a compressor
unit 250 having an air inlet 254 and a compressed air outlet 256,
an oxygen concentrator unit 260 having an air inlet 264 and a
compressed oxygen outlet 266, a compressed air passage 258, an
oxygen passage 268, a junction where the compressed air and
concentrated oxygen meet and mix at junction 270, and a vapor
transfer system 220 comprising a housing 222, a gas inlet 224, a
gas outlet 225, a gas passage 226 connecting the gas inlet 224 and
gas outlet 225, a liquid reservoir 234, a liquid inlet 227, a
liquid outlet 228, a liquid passage 230, a heater 238 and a
membrane 232 to separate the liquid passage 230 and the gas passage
226. The vapor transfer system 220, air compressor unit 250, and
oxygen concentrator unit 260 are all contained within the vapor
transfer system 220 housing 222. The system 200 is thus
self-contained and portable, allowing broad deployment of HFT into
the home or non-clinical environment while limiting clutter.
[0036] The system 200 intakes air 240 at an air inlet 242a and
242b. Though two inlets are shown, the system may have a single air
inlet 242a,b at which air is drawn in and directed to the air
compressor unit 250 and to the oxygen concentrator unit 260. Air
240 is directed into the air compressor unit 250 through an inlet
254. The air compressor unit 250 pressurizes the air 240. The air
compressor unit 250 may include a tank 253. Once pressurized, the
compressed air 252 is directed out of the air compressor unit 250
at a compressed air outlet 256 and into a compressed air passage
258. The compressed air 252 in the compressed air passage 258 may
have a first pressure 259. The pressure may be monitored.
[0037] The system 200 also directs air 240 into the oxygen
concentrator unit 260 through the air inlet 264. The oxygen
concentrator unit 260 is shown having two cylinders 261a and 261b.
The oxygen concentrator unit 260 may use pressure swing adsorption
technology making use of adsorptive materials including zeolites,
activated carbon, membrane separation of oxygen or molecular sieves
to concentrate oxygen 262 from ambient air 240. The concentrated
oxygen 262 is directed out of the oxygen concentrator unit 260
through a concentrated oxygen outlet 266 and into an oxygen passage
268. The concentrated oxygen outlet 266 in the passage has a second
pressure 269. The oxygen passage 268 is in fluid communication with
the compressed air passage 258 at a junction 270. The first
pressure 259 of the compressed air 252 is matched to the second
pressure 269 of the concentrated oxygen 262. The matched pressures
may be equal or may be matched to within a percentage (e.g. to
within 2%, 5%, 7%, 10%, 15%). Matching the first pressure 259 of
the compressed air 252 and the second pressure 269 of the
concentrated oxygen 262 before mixing results in a smoother
blending process. The mixing of the compressed air 252 and
concentrated oxygen 262 may also be aided by the use of a manifold
or directing device at the junction 270 to direct the flows in a
single direction. The blending of concentrated oxygen 262 with
compressed air 252 at a matched pressure allows mixing of an
oxygen-air breathing gas mixture 274 having an appropriate
concentration of oxygen for therapeutic use.
[0038] The oxygen-air breathing gas mixture 274 continues through a
gas passage 272 and into a vapor transfer system 220 through a gas
inlet 224 leading to a gas passage 226 through the vapor transfer
system 220. The vapor transfer system 220 also includes a liquid
reservoir 234 which is fillable with a liquid such as water through
the liquid port 236. The liquid reservoir 234 includes a heater 238
which heats the liquid and produces a vapor. The vapor transfer
system 220 also includes a liquid inlet 227 through which liquid
leaves the liquid reservoir 234 and enters the liquid passage 230
and a liquid outlet 228 from the vapor transfer system 220. The gas
passage 226 is separated from the liquid passage 230 by a membrane
232 which allows the transfer of vapor from the liquid passage 230
to the gas passage 226. In some implementations the membrane 232
may be composed of a plurality of hollow fibers. In some
implementations the gas passage 226 may be enveloped by the liquid
passage 230. In other implementations the liquid passage 230 may be
enveloped by the gas passage 226. The transfer of vapor to the
oxygen-air breathing gas mixture 274 in the gas passage 272 allows
the oxygen-air breathing gas mixture 274 to become heated and
humidified before delivery to a patient.
[0039] The gas passage 226 directs the heated and humidified
oxygen-air breathing gas mixture 274 out of the vapor transfer
system 220 at a gas outlet 225. The heated and humidified
oxygen-air breathing gas mixture 274 may be further directed out of
the housing 222 through a housing gas outlet 276 for delivery to a
patient. The liquid in the liquid passage 230 may also be directed
out of the vapor transfer system 220 at a liquid outlet 228. The
liquid may be further directed out of the housing at a housing
liquid outlet 229 for collection.
[0040] Various aspects of the system 200 may be controlled by
controls 285 on a user display panel 280. The user may have
controls which adjust parameters including the temperature and
humidity of the oxygen-air breathing gas mixture 274. In some
implementations, the gas temperature may be adjustable between
ambient room temperature up to 43.degree. C., with humidity levels
adjustable between 90 and 100%. The controls may also adjust the
flow rate of the oxygen-air mixture and the ratio of the mixture of
oxygen and air in the heated and humidified oxygen-air breathing
gas mixture 274. In some implementations the system 200 may deliver
a continuous flow of heated and humidified oxygen-air breathing gas
mixture 274 at flow rates of 1-40 lpm. The oxygen admixture to the
flow may be varied between 0 lpm and 20 lpm. A power button may be
incorporated 283, as well as a flow meter displaying the flow rate
of the concentrated oxygen 288 and a flow meter displaying the flow
rate of the compressed air 287. The system 200 may be further
adapted by the addition of an IV pole 282. The system 200 is
self-contained and does not require use of external gas sources,
though they may be used. Additionally, the use of a low pressure
oxygen concentrator and a low pressure air compressor allows the
apparatus to operate at a sound level of 55 dB or lower.
[0041] In some implementations, the system 200 may be configured to
allow for the vapor transfer system 220 to be detachable from the
base unit 212. This allows for disposal of the vapor transfer
system 220 and reuse of the base unit 112. This further allows for
removal of the vapor transfer system for cleaning, inspection or
maintenance. In some implementations, the liquid passage 230 is
coupled to the base unit 212 for liquid flow between the base unit
212 and the vapor transfer system 220 when the vapor transfer
system is received by the base unit.
[0042] The heated and humidified oxygen-air breathing gas mixture
274 exits the housing 222 at a housing gas outlet 231. The heated
and humidified oxygen-air breathing gas mixture 274 may be routed
to the patient by a gas splitter 289 which directs the gas to a
first elongated lumen 292 having a first length L1 and a second
elongated lumen 294 having a second length L2. The first elongated
lumen 292 may be coupled the first end 296 of a nasal cannula 290.
The second elongated lumen 294 may be coupled to a second end 295
of the nasal cannula 290. The first elongated lumen 292 and the
second elongated lumen 294 is each composed of large inner
diameter, low-resistance tubing, allowing the oxygen-air breathing
gas mixture to achieve a high flow rate for delivery to the
patient. In some implementations, the first end 296 of the nasal
cannula 290 and the second end 295 of the nasal cannula 290 may be
connected by a bridging piece 298 which does not allow fluid
communication between the two ends (296 and 295). Though a nasal
cannula 290 is shown here having two nares not in fluidic
communication and separated by a bridging element 298, any suitable
nasal cannula or mask may be used to deliver the air-oxygen
breathing gas mixture to the patient. In other implementations, the
gas from the first elongated lumen 292 and the second elongated
lumen 294 may be in fluid communication within the nasal cannula
290. In some implementations, the gas from the first elongated
lumen 292 and the second elongated lumen 294 may be in fluid
communication at the point of administration of the gas via the
prongs of the nasal cannula 290 into the nose. In some
implementations the flow of gas through the first elongated lumen
292 may not be in fluid communication with the flow of gas through
the second elongated lumen 294 after leaving the gas splitter 289
until expulsion from the nasal cannula 290. In some implementations
the nasal cannula defines a constant diameter flow path. In some
implementations, the use of low resistance tubing with a large
inner diameter throughout the system allows a gas flow output of up
to 40 lpm. The use of tubing with a large inner diameter minimizes
the backpressure within the system. In some implementations, the
nasal cannula has a large inner diameter cross section at the
supply tubing and the inlet port with nasal prongs having a small
inner diameter. In some implementations an inner diameter of the
first and second elongated lumens may be the same for both the
first elongated lumen and the second elongated lumen and may be an
inner diameter about equal to 1/4'' (e.g. 3/8'', 1/4'', 5/8'',
1/2''). The use of tubing having an inner diameter of about 1/4''
provides the breathing gas to the patient at a high flow rate.
Additionally, the larger inner diameter tubing provides a favorable
ratio of surface area to volume and has a decreased rate of
condensation and rainout compared to smaller diameters of tubing.
The Biot number associated with tubing with an inner diameter of
about 1/4'' is large when compared to tubing with a smaller inner
diameter which may suffer from greater heat transference and more
condensation and rainout. In some implementations the flow rate
through the first elongated lumen may be 40 lpm or greater. Though
the delivery of the oxygen-air gas mixture is shown as through a
split nasal cannula, the gas may be delivered by any suitable nasal
cannula or patient interface including masks and tracheal
adaptors.
[0043] In some implementations the system 200 may be configured to
operate in two modes. A first mode may provide heated and
humidified oxygen-air breathing gas mixture 274 to a patient as
described. A second mode may provide a humidified but not heated
oxygen-air breathing gas mixture 274 to a patient. In some
implementations, the second mode allows for delivery of a high
concentration of oxygen gas (e.g. 90-93% oxygen) at flow rates of
1-20 lpm in a humidified but non-heated gas through a long length
of tubing. As the gas in the second mode is not heated, there is
decreased occurrence of rain-out or condensation during delivery of
the breathing gas through the length of tubing. The second mode may
allow for use of first and second elongated lumens (292 and 294) of
longer lengths, L1 and L2, respectively. A longer length of tubing
allows a patient receiving oxygen therapy in their own home to be
mobile while receiving the oxygen therapy. In some implementations,
the system 200 can switch between the delivery of high
concentration oxygen and delivery of HFT oxygen-air mixture having
a controllable oxygen concentration of between 21-93% oxygen which
may be flow rate dependent. Additionally, providing both oxygen
therapy and HFT via a single system decreases the need for further
equipment in the home environment and streamlines therapy. Thus in
some implementations, L1 and L2 may be 1.8 meters or longer (e.g.
1.8 m, 2 m, 2.5 m, 3 m) and the first elongated lumen 292 and the
second elongated lumen 294 may each provide gas at a flow rate of
5-40 lpm. Flow rates of 8-40 lpm are sufficient to provide the core
benefits of HFT. Administration of HFT with these flow rates
reduces the respiratory burden on a patient by warming and
humidifying them and serves to flush the dead space from the nasal
and pharyngeal cavities prior to inspiration. In some
implementations, L1 and L2 may be about 10 m in length (e.g. 7 m, 8
m, 9 m, 10 m, 11 m, 15 m) and the first elongated lumen 292 and the
second elongated lumen 294 may each provide gas at a flow rate of
about 2 lpm. A flow rate of 2 lpm is typically sufficient to
provide long term oxygen therapy to a patient. In some
implementations, the first elongated lumen 292 and the second
elongated lumen 294 may each provide gas at a flow rate of 0.25-10
lpm.
[0044] FIG. 4 shows a histogram 400 displaying temperature
performance of the system 100 over a variety of breathing gas
output flow rates. The y-axis 410 represents the temperature of the
oxygen and air mixture output by the system measured in degrees
Celsius. The x-axis 420 represents the set flow rate of the oxygen
and air mixture measured in lpm. The flow rate was varied from 5
lpm to 40 lpm in increments of 5 lpm. The temperature of the system
was set to 37.degree. C. and the temperature of the oxygen and air
mixture output from the system 100 at the gas outlet was measured
and recorded. The temperature performance of the system 100 is
displayed with the temperature performance of two other HFT
systems, the PF Unit and the Palladium. The histogram 400 shows
that the system 100 performs similarly to the PF Unit over the
range of flow rates tested. The histogram also shows that the
system 100 maintains the set temperature within about 5.degree. C.
over the range of flow rates tested. The recorded temperature of
the output oxygen and air mixture is about 42.degree. C. at 5 lpm
flow rate and is about 33.degree. C. at 40 lpm flow rate. The
system 100 is able to maintain a set temperature within about
5.degree. C. over flow rates ranging from 5 lpm to 40 lpm.
[0045] FIG. 5 shows a histogram 500 displaying humidification
performance of the system over a variety of breathing gas output
flow rates. The x-axis 520 represents the set flow rate of the
oxygen and air mixture output by the system 100 measured in lpm.
The y-axis 510 represents the measured absolute humidity of the
oxygen and air mixture in mg/l. The humidification performance of
the system 100 is displayed with the humidification performance of
two other HFT systems, the PF Unit and the Palladium. The flow rate
was varied from 5 lpm to 40 lpm in increments of 5 lpm. The
temperature of the system was set to 37.degree. C. and the humidity
of the oxygen and air mixture output from the system 100 at the gas
outlet was measured and recorded for each of the input flow rates.
The histogram 500 shows that the system 100 performs similarly to
the PF Unit at all tested flow rates and performs similarly to the
Palladium unit at flow rates of 20-40 lpm. The histogram shows that
the system 100 provides absolute humidity levels of between 35 mg/L
and 55 mg/L at 37.degree. C. over flow rates of 5 lpm to 40
lpm.
[0046] FIG. 6 shows a graph 600 displaying oxygen enrichment of the
system over a variety of output flow rates. The x-axis 610 displays
the total flow in lpm of the air oxygen mixture from the outlet.
The oxygen concentrator unit 160 was set to its maximum flow rate
of 5 lpm and the total flow is adjusted upward to increase the
total flow of oxygen and air from the vapor transfer unit 120. The
y-axis 620 displays the oxygen concentration as a percent measured
at the output of the oxygen air mixture from the system 100. The
oxygen enrichment of the system 100 is displayed with the oxygen
enrichment of two other HFT systems, the PF Unit and the Palladium.
The measured value is displayed as a line 630, while the
theoretical value is also displayed as a dashed line 640. The
theoretical performance is calculated as the optimal performance
assuming the optimal concentrator oxygen fraction of 0.92. Though
the concentrator was set to its maximum output flow of 5 lpm, the
concentrator did not generate a flow rate of 5 lpm, but rather 4.2
lpm of flow. The graph shows that the oxygen enrichment performance
of the system 100 is similar to the theoretical optimal
performance.
[0047] FIG. 7 shows an illustrative process 700 for achieving a
heated and humidified air-oxygen mixture for delivery to a patient.
The process 700 can be performed using either of the systems 100 or
200 described herein. It will be understood by one of ordinary
skill in the art that, in addition to the steps shown in FIG. 7,
the heated and humidified air-oxygen mixture may be delivered to a
patient by any suitable means.
[0048] In step 702, air is passed form an air compressor unit 150
to a compressed air passage 158. The air passed from the air
compressor unit 150 has a first pressure 159 which may be
determined by an input from the controls of the system 100 or 200.
The air compressor unit 150 may draw air 140 into the air
compressor unit 150 through an air inlet 142 before compressing the
air 152 and expelling it from the air outlet 156 into a compressed
air passage 158. The air may be ambient room air. Though the air
inlet 142 is depicted as drawing ambient room air, in some
implementations the system 100, 200 may also allow attachment of
high or low pressure external air and oxygen sources.
[0049] In step 704, oxygen is passed from an oxygen concentrator
unit 160 to an oxygen passage 168. The oxygen concentrator unit 160
may draw air 140 into the concentrator unit 160 through an air
inlet 142. The air may be ambient room air. The oxygen concentrator
unit 160 concentrates the oxygen in the air 140 and expels
concentrated oxygen 162 through a concentrated oxygen outlet 166
and into the oxygen passage 168. The concentrated oxygen 162 has a
second pressure 169.
[0050] In step 706, the oxygen from the oxygen concentrator unit
160 and the compressed air from the air compressor unit 150 are
mixed at the junction 170. The concentrated oxygen 162 meets the
compressed air 152 at the junction 170 of the compressed air
passage 158 and the oxygen passage 168. The compressed air 152 has
a first pressure 159 which is about equal to the second pressure
169 of the concentrated oxygen 162. The compressed air 152 and the
concentrated oxygen 162 mix without one gas overcoming the other
due to the matched pressure. The mixing of the compressed air 152
and the concentrated oxygen 162 at the junction 170 may be enhanced
by the presence of a manifold or other director to direct the flows
of the compressed air 152 and concentrated oxygen 162 for a smooth
blending.
[0051] In step 708, the air 140 and oxygen 162, which have been
mixed into an air-oxygen breathing gas mixture 174, are passed
through the vapor transfer system 120. The vapor transfer system
120 includes a liquid reservoir 134 and means to heat the liquid
138. The heated liquid and vapor are passed through a liquid
passage 130. The air-oxygen breathing gas mixture 174 is directed
through a gas passage 126 which is separated from the liquid
passage 130 by a membrane 132 which allows the transfer of vapor to
the air-oxygen breathing gas mixture 174 in order to heat and
humidify the air-oxygen breathing gas mixture 174. The humidity and
heat of the air and oxygen mixture may be controlled. The
humidified and heated air-oxygen breathing gas mixture 174 is then
passed out of the system for delivery to a patient via a nasal
cannula 290 or any other suitable means.
[0052] Variations and modifications will occur to those of skill in
the art after reviewing this disclosure. The disclosed features may
be implemented, in any combination and subcombination (including
multiple dependent combinations and subcombinations), with one or
more other features described herein. The various features
described or illustrated above, including any components thereof,
may be combined or integrated in other systems. Moreover, certain
features may be omitted or not implemented.
[0053] Examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the scope of the information disclosed herein. All
references cited herein are incorporated by reference in their
entirety and made part of this application.
* * * * *