U.S. patent application number 15/146150 was filed with the patent office on 2016-08-25 for respiratory ventilation system with gas sparing valve having optional cpap mode and mask for use with same.
The applicant listed for this patent is Capnia, Inc.. Invention is credited to Mark DeStefano.
Application Number | 20160243330 15/146150 |
Document ID | / |
Family ID | 56027684 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160243330 |
Kind Code |
A1 |
DeStefano; Mark |
August 25, 2016 |
Respiratory Ventilation System with Gas Sparing Valve Having
Optional CPAP Mode and Mask for Use with Same
Abstract
A system for delivering gas to a patient. The system includes a
gas control unit, a breathing circuit, a control switch, and a
patient interface. The gas control unit has a main gas outlet. The
breathing circuit has a main gas line having a first end. The first
end of the main gas line is coupled to the main gas outlet. The
control switch may be a pneumatic switch, in which case the
breathing circuit further has a pilot control line for
pneumatically controlling the gas control unit to deliver gas to
the main gas line via the main gas outlet. The control switch may
be an electrical switch, in which case the breathing circuit may
use electrical control of the gas delivery or electrical and
pneumatic control of the gas delivery. Other embodiment of the gas
control unit may include a continuous positive airway pressure
branch.
Inventors: |
DeStefano; Mark;
(Collegeville, PA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Capnia, Inc. |
Redwood City |
CA |
US |
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|
Family ID: |
56027684 |
Appl. No.: |
15/146150 |
Filed: |
May 4, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13680793 |
Nov 19, 2012 |
9352115 |
|
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15146150 |
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61561465 |
Nov 18, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 16/208 20130101;
A61M 16/04 20130101; A61M 16/207 20140204; A61M 16/06 20130101;
A61M 16/202 20140204; A61M 16/0677 20140204; A61M 16/0841 20140204;
A61M 16/0875 20130101; A61M 16/201 20140204; A61M 16/20
20130101 |
International
Class: |
A61M 16/20 20060101
A61M016/20; A61M 16/04 20060101 A61M016/04; A61M 16/06 20060101
A61M016/06 |
Claims
1. A system for delivering gas to a patient, comprising: a gas
control unit comprising an outlet comprising a main gas line
outlet, the gas control unit further comprising a gas sparing
circuit comprising a primary branch coupled to the main gas line
outlet, the primary branch comprising a gas sparing valve for
controlling a flow of gas through the primary branch; a breathing
circuit comprising a main gas line comprising a first end and a
second end, the first end of the main gas line coupled to the main
gas line outlet; a pilot control switch for selectively causing the
gas sparing valve to provide the flow of gas to the main gas line
via the main gas line outlet; and a patient interface coupled to
the second end of the main gas line of the breathing circuit.
2. The system of claim 1, wherein: the outlet of the gas control
unit further comprises a pilot control line outlet, the breathing
circuit further comprises a pilot control line coupled to the pilot
control line outlet, the pilot control switch is a pneumatic
control switch for selectively occluding the pilot control line,
the gas sparing circuit further comprises a pilot control branch
coupled to the pilot control line outlet, and the gas sparing valve
is a pneumatic control valve disposed in the primary branch, the
pilot control switch configured to actuate the pneumatic control
valve based on the selective occlusion of the pilot control line by
the pneumatic control switch to provide the flow of gas to the main
gas line via the main gas line outlet.
3. The system of claim 2, wherein the patient interface is a mask
coupled to the second end of the main gas line of the breathing
circuit, and the pneumatic control switch is disposed on the
mask.
4. The system of claim 2, wherein the patient interface is an
endotracheal tube adapter for connection to an endotracheal tube,
and the pneumatic control switch is disposed on the endotracheal
tube adapter.
5. The system of claim 1, wherein: the gas control unit further
comprises an electric solenoid control valve and an electrical
pilot control line input, the breathing circuit further comprises
an electrical pilot control line, and the pilot control switch is
an electrical control switch coupled to the electrical pilot
control line for selectively controlling the electric solenoid
control valve to control the gas sparing valve to provide the flow
of gas to the main gas line via the main gas line outlet.
6. The system of claim 5, wherein the patient interface is a mask
coupled to the second end of the main gas line of the breathing
circuit, and the electrical control switch is disposed on the
mask.
7. The system of claim 5, wherein the patient interface is an
endotracheal tube adapter for connection to an endotracheal tube,
and the electrical control switch is disposed on the endotracheal
tube adapter.
8. The system of claim 1, wherein: the gas control unit further
comprises a continuous positive airway pressure (CPAP) branch
coupled to the main gas outlet, and a mode-selection switch for
selectively directing source gas to the CPAP branch or to the gas
sparing circuit, and the patient interface is a mask coupled to the
second end of the main gas line of the breathing circuit, the mask
comprising a CPAP exhalation port.
9. The system of claim 1, wherein the gas control unit further
comprises an internal air supply that sources the flow of gas to
the main gas line, and wherein the primary branch is further
coupled to internal air supply.
10. The system of claim 1, wherein the pilot control switch is a
pneumatic-mechanical timer-based trigger.
11. A gas control unit for delivering gas to a patient, comprising:
an outlet comprising a main gas line outlet; and a gas sparing
circuit comprising: a primary branch coupled to the main gas line
outlet; and a gas sparing valve for controlling a flow of gas to
the main gas outlet in response to a selective control.
12. The gas control unit of claim 11, wherein: the outlet further
comprises a pilot control line outlet, the gas sparing circuit
further comprises a pilot control branch coupled to the pilot
control line outlet, and the gas sparing valve is a pneumatic
control valve comprising a pneumatic control input coupled to the
pilot control branch, the pneumatic control valve disposed in the
primary branch and configured to actuate in response to the
selective control to provide the flow of gas to the main gas line
outlet.
13. The gas control unit of claim 12, further comprising a first
pneumatic timer control disposed in the pilot control branch, the
first pneumatic timer control configured to control an on-time of
the pneumatic control valve in response to the selective control to
provide the flow of gas to the main gas line outlet.
14. The gas control unit of claim 13, further comprising a second
pneumatic timer control disposed in the pilot control branch, the
second pneumatic timer control configured to control an off-time of
the pneumatic control valve in response to the selective control to
provide the flow of gas to the main gas line outlet.
15. The gas control unit of claim 11, wherein: the gas control unit
further comprises an electrical pilot control line input, the gas
sparing valve is controlled by an electric solenoid control valve
disposed in the pilot branch, the electric solenoid control valve
configured to actuate in response to the selective control to
actuate the gas sparing valve to provide the flow of gas to the
main gas outlet.
16. The gas control unit of claim 15, further comprising an
electrical timer control configured to receive the selective
control via the electrical pilot control line input and to control
an on-time and an off-time of the electric solenoid control valve
in response to the selective control to provide the flow of gas to
the main gas line outlet.
17. The gas control unit of claim 11, further comprising a
continuous positive airway pressure (CPAP) branch coupled to the
main gas outlet, and a mode-selection switch for selectively
directing source gas to the CPAP branch or to the gas sparing
circuit.
18. A patient interface for use with a gas sparing circuit for
delivering gas to a patient, comprising: an output for delivering
the gas to the patient; an input for receiving the gas from a
source; and a control switch for selectively controlling the
delivery of the gas to the patient.
19. The patient interface of claim 18, wherein the control switch
is a pneumatic switch configured for selectively occluding a pilot
control line to control the delivery of the gas to the patient.
20. The patient interface of claim 18, wherein the control switch
is an electric switch configured for selectively causing a gas
sparing valve to be actuated to control the delivery of the gas to
the patient.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 13/680,793, filed Nov. 19, 2012, entitled "Respiratory
Ventilation System with Gas Sparing Valve having Optional CPAP Mode
and Mask for Use with Same," which application claims benefit of
priority of U.S. Provisional Application No. 61/561,465, filed Nov.
18, 2011. Each of the above-identified related applications are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates, generally, to a respiratory
ventilation system that controls gas delivery to a patient and,
particularly, to a respiratory ventilation system that utilizes a
gas sparing valve to conserve gas. More particularly, the present
invention relates to a pneumatically controlled respiratory
ventilation system that utilizes a pilot circuit to control gas
flow in a main gas supply circuit to thereby conserve gas supplied
to a patient.
BACKGROUND OF THE INVENTION
[0003] Ventilation is the physiologic process of moving a gas into
(inspiration) and out of (expiration) the lungs of a patient,
thereby delivering oxygen to organs of the patient and excreting
carbon dioxide. During spontaneous ventilation, i.e. unassisted
breathing, negative (sub-atmospheric) pressure is created within
the chest of the patient. As a result, gas moves into the lungs of
the patient.
[0004] In the practice of medicine, there is often a need to
substitute mechanical ventilatory support for the spontaneous
breathing of a patient. Mechanical ventilation is a method to
mechanically assist or replace spontaneous breathing. This may
involve a machine called a ventilator. Alternatively, the breathing
of the patient may be assisted by a physician or other suitable
person compressing a bag or set of bellows. In positive pressure
ventilation, air (or another gas mix, e.g., oxygen mix) is pushed
into the trachea of the patient. The positive pressure forces air
to flow into the airway to expand and fill the lungs until the
inspiration breath is terminated. Subsequently, the airway pressure
drops, and the elastic recoil of the chest wall and lungs push the
tidal volume, the breath, out through passive expiration or
exhalation.
[0005] Mechanical ventilation may be necessary during respiratory
failure or when patients are placed under anesthesia. Particular
examples are patients with acute lung injury, including acute
respiratory distress syndrome (ARDS); apnea with respiratory
arrest, including cases from intoxication; chronic obstructive
pulmonary disease (COPD); acute respiratory acidosis; respiratory
distress; hypoxemia; hypotension including sepsis; shock;
congestive heart failure; and neurological diseases such as
Muscular Dystrophy and Amyotrophic Lateral Sclerosis; etc.
SUMMARY OF THE INVENTION
[0006] In accordance with an exemplary aspect of the present
invention, there is provided a system for delivering gas to a
patient. The system includes a gas control unit, a breathing
circuit, a pilot control switch, and a patient interface. The gas
control unit includes an outlet having a main gas line outlet. The
gas control unit further includes a gas sparing circuit having a
primary branch coupled to the main gas line outlet. The primary
branch includes a gas sparing valve for controlling a flow of gas
through the primary branch. The breathing circuit includes a main
gas line having a first end and a second end. The first end of the
main gas line is coupled to the main gas line outlet. The pilot
control switch is for selectively causing the gas sparing valve to
provide the flow of gas to the main gas line via the main gas line
outlet. The patient interface is coupled to the second end of the
main gas line of the breathing circuit.
[0007] In accordance with another exemplary aspect of the present
invention, there is provided a pneumatic system for delivering gas
to a patient. The pneumatic system includes a gas control unit, a
breathing circuit, a pilot control switch, and a patient interface.
The gas control unit includes an outlet having a pilot control line
outlet and a main gas line outlet. The breathing circuit includes a
pilot control line having a first end and a second end. The
breathing circuit also includes a main gas line having a first end
and a second end. The first end of the pilot control line is
coupled to the pilot control line outlet, and the first end of the
main gas line is coupled to the main gas line outlet. The pilot
control switch allows a user to selectively cause the gas control
unit to provide gas to the main gas line via the main gas line
outlet. The patient interface is coupled to the second end of the
main gas line of the breathing circuit.
[0008] In accordance with a further exemplary aspect of the present
invention, there is provided a pneumatic system for delivering gas
to a patient. The pneumatic system includes a gas control unit,
which includes an outlet having a pilot control line outlet and a
main gas line outlet and a gas sparing circuit. The gas sparing
circuit includes a primary branch coupled to the main gas line
outlet, a pilot control branch coupled to the pilot control line
outlet, a pneumatic control valve disposed in the primary branch,
the pneumatic control valve comprising a control input, and a timer
circuit comprising an output coupled to the control input of the
pneumatic control valve. The pneumatic system also includes a
breathing circuit having a pilot control line a main gas line. The
pilot control line includes a first end and a second end, and the
main gas line includes a first end and a second end. The first end
of the pilot control line is coupled to the pilot control line
outlet, and the first end of the main gas line is coupled to the
main gas line outlet. The pneumatic system further includes a pilot
control switch for selectively causing the pneumatic control valve
to open to provide gas to the main gas line via the main gas line
outlet and for activating the pneumatic timer to close the
pneumatic control valve after a predetermine amount of time. A
patient interface is coupled to the second end of the main gas line
of the breathing circuit.
[0009] In accordance with still another exemplary aspect of the
present invention, there is provided a pneumatic system for
delivering gas to a patient. The pneumatic system includes a gas
control unit having an outlet including a pilot control line outlet
and a main gas line outlet. The pneumatic system also includes a
breathing circuit, a pilot control switch, and an endotracheal hand
piece configured to couple the breathing circuit to an endotracheal
tube. The breathing circuit includes a pilot control line having a
first end and a second end and a main gas line having a first end
and a second end. The first end of the pilot control line is
coupled to the pilot control line outlet, and the first end of the
main gas line is coupled to the main gas line outlet. The pilot
control switch allows for a user to selectively cause the gas
control unit to provide gas to the main gas line via the main gas
line outlet.
[0010] In accordance with yet another exemplary aspect of the
present invention, there is provided a pneumatic system for
delivering gas to a patient. The pneumatic system includes a gas
control unit, a breathing circuit, a pilot control switch, and a
patient interface. The gas control unit includes a pilot branch, a
primary branch, a continuous positive airway pressure (CPAP)
branch, and an outlet having a pilot control line outlet coupled to
the pilot branch and a main gas line outlet coupled to the primary
branch and the CPAP branch. The gas control unit further includes a
directional flow control valve for selecting for gas to flow to the
main gas line outlet via the primary branch or the CPAP branch. The
breathing circuit includes a pilot control line having a first end
and a second end and a main gas line having a first end and a
second end. The first end of the pilot control line is coupled to
the pilot control line outlet, and the first end of the main gas
line is coupled to the main gas line outlet. The pilot control
switch allows a user to selectively cause the gas control unit to
provide gas to the main gas line via the main gas line outlet. The
patient interface is coupled to the second end of the main gas line
of the breathing circuit.
[0011] In accordance with another aspect of the present invention,
there is provided a gas control unit. In one embodiment, the gas
control unit includes an outlet having a main gas line outlet, and
a gas sparing circuit including a primary branch coupled to the
main gas line outlet and a gas sparing valve for controlling a flow
of gas through the primary branch in response to a selective
control. In another embodiment, the gas control unit includes an
inlet line, an outlet port having a pilot control line outlet and a
main gas line outlet, and a gas sparing circuit. The gas sparing
circuit includes a primary branch coupled to the inlet line and the
main gas line outlet, a pilot control branch coupled to the inlet
line and the pilot control line outlet, and a pneumatic control
valve disposed in the primary branch. The pneumatic control valve
includes an input coupled to the inlet line, an output coupled to
the main gas line outlet, and a control input coupled to the pilot
branch. The pneumatic control valve is configured to be actuated
after occlusion of the pilot control branch to allow gas to flow
through the primary branch to the main gas line outlet.
[0012] In accordance with yet another embodiment of the present
invention, there is provided a valve system having a one-way
breathing valve for providing primary gas from a source system to a
patient upon inhalation, a one-way exhaust valve for exhausting gas
from the patient upon exhalation, and an air inlet valve for
inletting gas from atmosphere when demand for gas from the patient
during inhalation exceeds the gas from the source system.
[0013] In accordance with yet another embodiment of the present
invention, there is provided a patient interface for use with a gas
sparing circuit. The patient interface may include a patient mask
interface or an endotracheal tube connection. The patient interface
may also include a vent port for exhalation by a user of the
patient interface during a continuous positive airway pressure
(CPAP) mode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For the purpose of illustration, there are shown in the
drawings certain embodiments of the present invention. In the
drawings, like numerals indicate like elements throughout. It
should be understood, however, that the invention is not limited to
the precise arrangements, dimensions, and instruments shown. In the
drawings:
[0015] FIG. 1 illustrates an exemplary embodiment of a system for
delivering gas to a patient, the system comprising a gas control
unit, a disposable breathing circuit, and a mask, the gas control
unit comprising a gas sparing circuit comprising a primary branch
and a pilot control branch, the primary branch comprising a gas
sparing valve, in accordance with an exemplary embodiment of the
present invention;
[0016] FIG. 2 illustrates an exemplary embodiment of an alternative
system for delivering gas to a patient, the alternative system
comprising a gas control unit, a disposable breathing circuit, and
a mask, the gas control unit comprising a gas sparing circuit
comprising a primary branch, a pilot control branch, and a
continuous positive airway pressure (CPAP) branch, the primary
branch comprising a gas sparing valve, in accordance with an
exemplary embodiment of the present invention;
[0017] FIG. 3 illustrates an exemplary block diagram of the
exemplary embodiment of the system of FIG. 1, in accordance with an
exemplary embodiment of the present invention;
[0018] FIG. 4 illustrates an exemplary block diagram of the
exemplary embodiment of the system of FIG. 2, in accordance with an
exemplary embodiment of the present invention;
[0019] FIGS. 5A through 5C illustrate various exemplary embodiments
of an external gas port used with the gas control units of FIGS. 1
and 2, the external gas port comprising pilot and main outlets, in
accordance with an exemplary embodiment of the present
invention;
[0020] FIG. 6 illustrates an exemplary simplified block diagram of
the exemplary embodiment of the gas sparing circuit of FIG. 1 or
FIG. 2, in accordance with an exemplary embodiment of the present
invention;
[0021] FIG. 7A illustrates a graph of exemplary pressures at
various points in the exemplary simplified block diagram
illustrated in FIG. 6, in accordance with an exemplary embodiment
of the present invention;
[0022] FIG. 7B illustrates a graph of exemplary gas flow through
the primary branch and the pilot control branch in the gas sparing
circuit of FIG. 1 or FIG. 2, in accordance with an exemplary
embodiment of the present invention;
[0023] FIGS. 8A and 8B illustrate exemplary operation of an
exemplary embodiment of a pilot control switch used to selectively
occlude the pilot control branches of FIGS. 1 and 2, in accordance
with an exemplary embodiment of the present invention;
[0024] FIGS. 8C through 8E illustrate various views of an exemplary
alternative embodiment of a disposable breathing circuit, in
accordance with an exemplary embodiment of the present
invention;
[0025] FIG. 9 illustrates an exemplary embodiment of a gas sparing
circuit comprising a timer control for main-flow on-time control,
in accordance with an exemplary embodiment of the present
invention;
[0026] FIG. 10 illustrates another exemplary embodiment of a gas
sparing circuit comprising a timer control for main-flow on-time
and off-time control, in accordance with an exemplary embodiment of
the present invention;
[0027] FIGS. 11A and 11B illustrate exemplary views of an exemplary
embodiment of a timer-based trigger used to selectively occlude the
pilot control branches of FIGS. 1 and 2, the timer-based trigger
providing main-flow on-time control, in accordance with an
exemplary embodiment of the present invention;
[0028] FIG. 12 illustrates an exemplary embodiment of a mask
connection for use with a gas sparing circuit, the mask connection
comprising a spontaneous breath valve, in accordance with an
exemplary embodiment of the present invention;
[0029] FIG. 12A illustrates an exemplary alternative embodiment of
the spontaneous breath valve of FIG. 12, in accordance with an
exemplary embodiment of the present invention;
[0030] FIGS. 12B and 12C respectively illustrate side
cross-sectional and top views of the exemplary embodiment of the
mask connection of FIG. 12 connected to the exemplary alternative
embodiment of the disposable breathing circuit of FIG. 8C, in
accordance with an exemplary embodiment of the present
invention;
[0031] FIG. 13 illustrates an exemplary embodiment of a hand piece
for controlling operation of a gas sparing circuit, the hand piece
comprising a pilot control switch, in accordance with an exemplary
embodiment of the present invention;
[0032] FIG. 13A illustrates an exemplary embodiment of the pilot
control switch of FIG. 13, in accordance with an exemplary
embodiment of the present invention;
[0033] FIG. 14 illustrates an exemplary embodiment of a system
incorporating the hand piece of FIG. 13, in accordance with an
exemplary embodiment of the present invention;
[0034] FIG. 15 illustrates an exemplary embodiment of an
endotracheal hand piece for control operation of a gas sparing
circuit, in accordance with an exemplary embodiment of the present
invention;
[0035] FIGS. 16A and 16B illustrate exemplary alternative
embodiments of masks with integrated hand pieces for control
operation of a gas sparing circuit, in accordance with an exemplary
embodiment of the present invention;
[0036] FIG. 17 illustrates an exemplary embodiment of a mask with a
CPAP port for use with a system providing resuscitation and CPAP
air delivery, in accordance with an exemplary embodiment of the
present invention;
[0037] FIG. 18 illustrates another view of the exemplary embodiment
of the hand piece of FIG. 13 showing the pilot control switch
attached to the mask, in accordance with an exemplary embodiment of
the present invention;
[0038] FIG. 19 illustrates an exemplary alternative embodiment of a
hand piece for controlling operation of a gas sparing circuit, in
accordance with an exemplary embodiment of the present
invention;
[0039] FIGS. 20A through 20C illustrate various views of another
alternative embodiment of a hand piece for controlling operation of
a gas sparing circuit, in accordance with an exemplary embodiment
of the present invention;
[0040] FIG. 21 illustrates a view of an exemplary housing for the
gas control unit of FIG. 2, in accordance with an exemplary
embodiment of the present invention;
[0041] FIGS. 22A through 22C illustrate various views of another
exemplary embodiment of a mask with a CPAP port for use with a
system providing resuscitation and CPAP air delivery, in accordance
with an exemplary embodiment of the present invention;
[0042] FIGS. 23A through 23F illustrate various views of various
components of a combination of the mask of FIGS. 22A through 22C
connected to the mask connection of FIG. 12, which is connected to
the exemplary alternative embodiment of the disposable breathing
circuit of FIG. 8C, in accordance with an exemplary embodiment of
the present invention;
[0043] FIG. 24 illustrates an exemplary block diagram of an
exemplary embodiment of a system for delivering gas to a patient
using electrical solenoid and electrical switch control of a pilot
control branch, in accordance with an exemplary embodiment of the
present invention;
[0044] FIG. 25 illustrates an exemplary block diagram of an
exemplary embodiment of a system for delivering gas to a patient
using electrical switch control of a gas sparing valve, in
accordance with an exemplary embodiment of the present
invention;
[0045] FIG. 26A illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing using selectable manual pilot
line control and electrical timer control of a gas sparing valve,
in accordance with an exemplary embodiment of the present
invention;
[0046] FIG. 26B illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing circuit of using selectable
manual pilot line control of a gas sparing valve and electrical
timer control of the gas sparing valve contained in an external,
removable module, in accordance with an exemplary embodiment of the
present invention;
[0047] FIG. 27 illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing circuit using selectable
manual pilot line control of a gas sparing valve and pneumatic
timer control of the gas sparing valve, in accordance with an
exemplary embodiment of the present invention;
[0048] FIG. 28 illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing circuit using a timer control
for main-flow on-time and off-time control implemented with two
on-time timers, in accordance with an exemplary embodiment of the
present invention;
[0049] FIG. 29 illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing circuit using selectable
manual pilot line control of a gas sparing valve and pneumatic
timer for main-flow on-time and off-time control utilizing two
on-time timers, in accordance with an exemplary embodiment of the
present invention;
[0050] FIG. 30 illustrates an exemplary block diagram of an
exemplary embodiment of a gas sparing circuit comprising a pressure
surge damping element to eliminate pressure surges when a gas
sparing valve is opened, in accordance with an exemplary embodiment
of the present invention;
[0051] FIG. 30A illustrates an exemplary embodiment of the pressure
surge dampening element of FIG. 30, in accordance with an exemplary
embodiment of the present invention;
[0052] FIG. 31A illustrates a graph of exemplary gas pressure
through the primary branch in the exemplary embodiment of the gas
sparing circuit illustrated in FIG. 3, in accordance with an
exemplary embodiment of the present invention;
[0053] FIG. 31B illustrates a graph of exemplary gas pressure
through the primary branch in the exemplary embodiment of the gas
sparing illustrated in FIG. 30, in accordance with an exemplary
embodiment of the present invention; and
[0054] FIG. 32 illustrates an exemplary embodiment of an
endotracheal hand piece for control operation of a gas sparing
circuit including a CPAP port for CPAP functionality, in accordance
with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0055] Conventional pneumatic flow circuits or devices do not allow
for resuscitation gas flow to be controlled pneumatically. Although
it is possible to put a spring-actuated flow control valve near an
outlet point of a conventional pneumatic flow circuit, this
placement of the flow control valve would make the pneumatic flow
circuit complicated and bulky. Further, because the portion of the
pneumatic flow circuit connected to the patient may be disposable,
placement of the flow control valve on the disposable portion would
result in a possibly unacceptable increase in cost of the
disposable portion. Further, locating the flow control valve in the
disposable portion may not allow for a pop off and peak inspiratory
pressure (PIP) pressure control valve arrangement with a gauge
remotely located within the pneumatic flow circuit. If located
after the flow control valve in the disposable portion, such
components would make the disposable portion bulky and expensive.
Locating such pressure control valve arrangement at the patient
site may increase the size and cost of the disposable portion.
[0056] Conventional manual and pneumatic devices suffer from
numerous disadvantages, such as continuous large gas flows, no flow
control, and no pressure control. In addition, some devices waste
significant amounts of compressed gases, thereby causing compressed
gas tanks to have very limited life. Furthermore, conventional
pneumatic devices do not offer the option of delivering fixed, user
set flow rates in a continuous positive airway pressure (CPAP) mode
through a combined resuscitation and CPAP unitary breathing circuit
and mask assembly.
[0057] An exemplary embodiment of the present invention provides a
gas sparing circuit that minimizes the continuous large gas flows
from conventional pneumatic devices while allowing for user
activation of the large gas flows required for resuscitation. In
addition, the gas sparing circuit allows for precise pressure and
volume control to the patient currently not available in
conventional resuscitation devices.
[0058] Referring now to FIG. 1, there is illustrated a block
diagram of a system, generally designated as 100, for delivering
gas to a patient, in accordance with an exemplary embodiment of the
present invention. The system comprises a gas control unit 110, a
disposable breathing circuit 120, and a patient mask 130. The
disposable breathing circuit 120 operates in a resuscitation mode
to deliver resuscitating gas to a patient (not illustrated) via a
patient mask 130 worn by the patient. A first end 121 of the
disposable breathing circuit 120 is coupled to the gas control unit
110, and a second end 122 of the disposable breathing circuit 120
is coupled to a connection port 131 of the patient mask 130 to
deliver gas to the patient during inhalation. The mask 130
interfaces with the patient via a patient-mask interface 132. A
pilot control switch 125 is disposed near the end 122 of the
disposable breathing circuit 120 for selective control of main gas
delivery flow to the patient. In one exemplary embodiment, the gas
comprises air. In another exemplary embodiment, the gas comprises
an oxygen mixture. Although not illustrated, it is to be understood
that, in an exemplary embodiment, the mask 130 may include one or
more exhaust ports to allow for exhalation by the patient.
[0059] The basic principle of operation for the system 100 is to
utilize a pneumatic pilot controlled valve in the gas control unit
110. As discussed below with respect to FIG. 3, the pneumatic pilot
controlled valve is coupled to a high pressure, low flow small
diameter pilot control circuit that is controlled by a user, such
as a medical practitioner, to control a high pressure, high flow
main gas circuit to provide on-demand high flow to the patient when
needed and to only allow a small trickle pilot flow when there is
no main gas demand. This control conserves gas supply by closing
the main gas circuit when not demanded. Demanded gas flows at a
rate of 35 to 50 liters/minute. A trickle flow of 1-3 liters/minute
flows through the pilot control circuit when there is no main gas
demand or need for gas by the patient. In an exemplary embodiment,
pilot gas flows through the pilot control circuit at not more than
2 liters per minute.
[0060] Accordingly, the gas control unit 110 comprises a gas inlet
111 and a gas port 112 comprising a pilot control port 116 and a
main gas port 117. (As used herein, the terms "port," "outlet," and
"outlet port" may be used interchangeably herein as context
permits. The same holds true for the terms "port," "inlet," and
"inlet port" and the terms "primary gas," "main gas," and "patient
gas.") The gas inlet 111 is coupled to a gas source (supply), such
as a wall source, compressed gas line, or a canister of compressed
breathing gas. The pilot control port 116 is coupled to a pilot
control line, and the main gas outlet 117 is coupled to a high
pressure, high flow main gas line. The gas control unit 110
includes a flow rate control selection means 115 to allow the user
to select a desired flow rate in the main gas line. An example of
selection means 115 is a flow control valve. The gas control unit
110 further comprises a flow meter 113 to display the current flow
rate of the gas through the inlet 111 and a pressure gauge 114 to
display the current gas pressure in the main gas outlet 117 being
delivered to the patient. The gas control unit 110 also comprises a
pop off maximum pressure relief valve 118 and a peak inspiratory
pressure (PIP) relief valve 119. Although the gas control unit 110
is configured for receiving gas from an external gas source via the
inlet 111, other exemplary embodiments are contemplated. For
example, it is contemplated that the gas control unit 110 may
comprise an internal gas source, such as an internal tank, for
storing primary gas, or internal gas pump.
[0061] The maximum pressure relief valve 118 allows the user to set
the maximum pressure that can build up in the gas control unit 110
and the disposable breathing circuit 120 before safely venting to
atmosphere. It ensures that pressure in the system 100 does not
exceed this maximum pressure. Thus, the valve 118 protects the
patient from the high main gas source outlet pressure, typically 50
psi.
[0062] The peak inspiratory pressure (PIP) valve 119 allows the
user to set the peak inspiratory pressure the patient will be
exposed to. Thus, the PIP valve 119 protects the patient from gas
delivery pressures above PIP pressure. In the event that gas
pressure at the main gas outlet 117 is above PIP, the PIP valve 119
opens to maintain the pressure at the outlet 117 at the PIP setting
to ensure that the pressure of the gas delivered to the mask 130 is
safe for the patient's lungs. The valve 118 acts as a safety valve
in the event that the PIP valve 119 fails to properly operate.
[0063] Referring now to FIG. 3, there is illustrated a block
diagram of a gas sparing circuit 300 comprising the gas control
unit 110, the disposable breathing circuit 120, and the patient
mask 130, in accordance with an exemplary embodiment of the present
invention. The gas sparing circuit 300 uses all of the components
illustrated in FIG. 1 and additional components, as illustrated in
FIG. 3.
[0064] The gas control unit 110 comprises a primary branch 310
comprising portions or lines 310A-310E and a secondary branch 320.
The secondary branch is a pilot control branch 320 comprising
portions or lines 320A-320D. The primary branch 310, specifically
the portion 310A of the primary branch 310, is coupled to the gas
inlet 111 via an inlet portion or line 305. The flow meter 113 and
the flow rate control 115, which may be separate components or a
unitary device, as illustrated in FIG. 3, are disposed within the
inlet portion 305. The flow meter 113 displays the flow rate of
supply gas through the gas inlet 111, and the flow rate control 115
allows a user or operator to modify this flow rate. In an exemplary
embodiment, the portions 305, 310A-E, and 320A-D are respective
tubes. As used herein, a user or operator may be the patient
receiving gas or may be a person, such as a medical practitioner,
who operates a gas control unit for benefit of a patient.
[0065] The portion 310A couples the primary branch 310 to the inlet
portion 305 and is coupled to a primary flow inlet 331 of a pilot
activated gas sparing valve 330 (also referred to herein as "pilot
valve 330" or "pneumatic control valve 330"). The gas sparing valve
330 additionally comprises a primary flow outlet 332 and a pilot
control input 333. The gas sparing valve 330 is normally closed,
i.e., when the pressure at the pilot control input 333 is below a
threshold pressure required to active the gas sparing valve 330,
the gas sparing valve 330 is closed, and no primary gas flows from
the primary flow inlet 331 to the primary flow outlet 332.
[0066] As described in more detail below, the pilot activated gas
sparing valve 330 is controlled by the pilot control branch 320 to
cause primary gas to flow through the primary flow outlet 332 of
the valve 330. Such outputted gas flows through a portion 310B of
the primary branch 310, through the pop off pressure relief valve
118, through a portion 310C of the primary branch 310, through the
PIP pressure relief valve 119, and through portions 310D-310E of
the primary branch 310 to the main gas outlet 117.
[0067] The pilot control branch 320, specifically the portion 320A
of the pilot control branch 320, is coupled to the gas inlet 111
via the inlet portion 305. The portion 320A connects through a
check valve 340 to a portion 320B. The portion 320B is connected to
a portion 320C via an element 341 for pilot flow reduction. In an
exemplary embodiment, the valve 341 is an orifice flow control
element. In another exemplary embodiment, the valve 341 is a needle
valve. The portion 320C is connected to the pilot control port
116.
[0068] The pilot control branch 320 is coupled to the control input
333 via a portion 320D of the pilot control branch 320, which
portion 320D is tapped into the portion 320C. As is discussed in
further detail below, the pilot control branch 320 controls the gas
sparing valve 330 via the pilot control input 333.
[0069] Additional details regarding the disposable breathing
circuit 120 are illustrated in FIG. 3 and are now described. The
disposable breathing circuit 120 comprises a main gas line 355
(also referred to herein as a "primary gas line 355") comprising a
first end 121 and a second end 122. The first end 121 of the main
gas line 355 is coupled to the main gas outlet 117 for delivering
source gas to the patient. The disposable breathing circuit 120
further comprises a pilot control line 365 comprising a first end
121 and a second end 123. The first end 121 of the pilot control
line 365 is coupled to the pilot control port 116. The pilot
control line 365 traverses the disposable breathing circuit 120
from the first end 121 to the pilot air flow control switch 125 at
the second end 123. Located at the end 123 of the pilot control
line 365 at the switch 125 is a vent port 351, which vents the end
123 of the pilot control line 365 to atmosphere. It is to be
understood that the end 123 of the pilot control line 365 and,
therefore, the pilot air flow control switch 125 may be disposed at
any place along the disposable breathing circuit 120. In an
exemplary embodiment, the end 123 of the pilot control line 365
and, therefore, the pilot air flow control switch 125 are disposed
near the end 122 of the disposable breathing circuit 120 for
convenience of use by the user activating the device for the
patient wearing the mask 130.
[0070] As also illustrated in FIG. 3, the second end 122 of the
disposable breathing circuit 120 is coupled to the mask 130 via a
mask connection 370. In an exemplary embodiment, the mask
connection 370 comprises a non-rebreathing element 371 which
comprises a flow in/vent out configuration 372, which may include
one or more exhaust ports to allow for exhalation by the patient.
In an exemplary alternative embodiment, the one or more exhaust
ports may be included in the mask 130 itself.
[0071] The pilot activated gas sparing valve 330 is controlled by
the pressure in the portion 320D at the pilot control input 333 of
the gas sparing valve 330. When the pressure at the pilot control
input 333 reaches a threshold pressure, the valve 330 actuates and
opens, thereby allowing full primary gas flow. When the pressure at
the pilot control input 333 decreases below the threshold
activating pressure, the valve 330 deactivates and closes, thereby
stopping full primary gas flow.
[0072] The primary branch 310 and the main gas line 355 together
form a main gas circuit 350 for delivering gas to a patient. The
pilot control branch 320 and the pilot control line 365 together
form a pilot control circuit 360 for controlling the delivery of
gas in the main gas circuit 350. By using a main gas circuit 350
and a pilot control circuit 360 coupled to the same inlet 111, the
same inlet gas flow is used to charge the main gas circuit 350 and
the pilot control circuit 360. It is to be understood that
description herein of occluding, un-occluding, charging, and
venting the pilot control circuit 360 may be referred to as
occluding, un-occluding, charging, and venting portions of the
pilot control circuit 360, such as the pilot control branch 320 or
the pilot control line, and vice versa.
[0073] FIGS. 5A through 5C illustrate alternative exemplary
embodiments of the gas port 112, in accordance with an exemplary
embodiment of the present invention. In a first exemplary
embodiment illustrated in FIG. 5A, the pilot control port 116 is
separate from the main gas port 117. In a second exemplary
embodiment illustrated in FIG. 5B, the pilot control port 116 is
disposed within the main gas port 117 to provide a unitary port
112. In a third exemplary embodiment illustrated in FIG. 5C, the
pilot control port 116 is disposed adjacent to and in contact with
the main gas port 117 to provide a unitary port 112. In such
embodiment, the unitary port 112 has a lopsided figure-8 cross
section.
[0074] Referring now to FIG. 6, there is illustrated an exemplary
block diagram of a system, generally designated as 600, which is a
simplified version of the gas sparing circuit 300, in accordance
with an exemplary embodiment of the present invention. The block
diagram 600 shows the gas sparing circuit 300 in terms of
pressures. Further, the block diagram 600 in conjunction with FIG.
7A shows how a charged pilot control circuit 360 aids in system
response. System response is plotted in FIG. 7A, which is described
below.
[0075] In an exemplary embodiment, the pilot valve 330 requires a
minimum threshold pressure P.sub.C to actuate and open the valve
330. It is to be understood that in any system, for a given circuit
size, e.g., the size of the pilot control circuit 360, there will
be a time value, t, for the full pressure in the system to build,
i.e., for the gas sparing circuit 300 to activate, when the system
is acted upon or, in the case herein, when the pilot control line
365 (pilot control circuit 360) is occluded.
[0076] The time t is affected by the total dead volume in the
circuit 360. Thus minimizing the dead volume by controlling the
interior diameter of the tubing in the circuit 360, the pliancy in
the tubing material, and the length to the occluding part, e.g.,
the length from the flow reduction element 341 to the pilot air
flow control switch 125, assists in reducing the time t. To reduce
the time t to activation even further, a pilot control circuit 360
that not only utilizes the lowest dead volume available but also
maintains a pressure as high as possible in the pilot control
circuit 360, i.e., as close to the activation pressure of the valve
330 as possible, allows for almost immediate activation of the
valve 330, thereby reducing the activation time t. Allowing a
constant, albeit small, flow in the pilot control circuit 360
allows the gas sparing circuit 300 to maintain a pressure in the
pilot control circuit 360 that is very close to the pressure
P.sub.C. Should the pilot control circuit 360 have no initial flow,
the time required to equalize to the system inlet pressure, once
flow is initiated and the circuit 360 occluded, would be
significantly greater than the subject pilot control circuit 360
with constant flow.
[0077] Because there is a desire to minimize vented or lost gas in
the main gas circuit 350, the flow rate in the pilot control
circuit 360 is desirably minimized. Thus, the gas control unit 110,
desirably includes a flow reduction element 341 which causes a
small drop in pressure in the pilot control branch 320 to just
below the threshold pressure P.sub.C of the valve 330 and which
limits the flow rate in the pilot control circuit 360 when not
occluded. A properly sized flow reduction element 341 in the pilot
branch 320 provides both pressure drop and flow rate control when
the pilot control circuit 360 is un-occluded and the gas in the
pilot control circuit 360 is allowed to flow. When the pilot
control circuit 360 is occluded and no flow occurs, i.e., when the
pilot air flow control switch 125 occludes the vent port 351, there
will be no pressure drop across the flow reduction element 341, and
the pressure in the pilot control circuit 360 will rise quickly,
because of the minimized circuit dead volume. The pressure in the
pilot control circuit 360 equalizes with the pressure at the inlet
111 to actuate the valve 330.
[0078] In FIG. 6:
P.sub.1=System inlet pressure (1)
P.sub.2=Pressure just after the flow reduction element 341 at the
pilot control input 333 of the gas sparing valve 330 (2)
P.sub.3=Pressure in the pilot control line 365 proximal to the vent
port 351 and at the end 122 of the main gas line 355 (3)
P.sub.C=Pressure at the input 333 required to actuate the valve 330
(4)
[0079] For the simplified system 600 of FIG. 6, the following
relationships hold true when the vent port 351 is open:
P.sub.2<P.sub.1 (5)
P.sub.2>P.sub.3, (6)
P.sub.2<P.sub.C.ltoreq.P.sub.1 (7)
[0080] By selecting the flow reduction element 341 and by reducing
dead volume and pliancy (expandability of components) in the pilot
control circuit 360, the pressure P.sub.2 can be held very close to
P.sub.C, such that upon occlusion of the pilot circuit, P.sub.2
quickly rises to the level of P.sub.1, which is greater than
P.sub.C, and actuates the valve 330.
[0081] Pilot control is accomplished by occluding and venting the
pilot control circuit 360, more specifically the control line 365.
FIG. 3 illustrates that the gas sparing circuit 300 comprises a
pilot air flow control switch 125. It is to be understood that the
gas sparing circuit 300 is not limited to the element 125 being a
switch. Any device to temporarily occlude the pilot control line
365 to actuate and open the gas sparing valve 330 is contemplated.
The pilot control switch 125 operates in a normally open condition
which holds the gas sparing valve 330 closed so that no gas flow
occurs through the main gas branch 310 and the main gas line
355.
[0082] Illustrated in FIG. 7A is a graph of the pressures, P.sub.1,
P.sub.2, and P.sub.3 in the system 600, plotted over time as the
pilot control circuit 360 is un-occluded, then is occluded, and
then re-un-occluded. Illustrated in FIG. 7B is a graph of the main
gas flow, designated as V.sub.1, in the main gas line 355 and the
pilot gas flow, designated as V.sub.2, in the pilot control line
365, in accordance with an exemplary embodiment of the present
invention. These graphs are now described with reference to
occluding and un-occluding the pilot control line 365.
[0083] As illustrated, when the system 600 is in its initial state
in which the pilot control circuit 360 is not occluded, the system
inlet pressure P.sub.1 remains relatively constant at a pressure
P.sub.A, the pressure in the line 305; pressure P.sub.2 remains
relatively constant at a pressure P.sub.B, the residual,
pre-charged pressure in (the original was better) the pilot control
circuit 360; and pressure P.sub.3 is constant at a pressure
P.sub.atm, atmospheric pressure, because the vent port 351 is open
to atmosphere. Main gas flow V.sub.1 is at 0 because the gas
sparing valve 330 is closed. Pilot gas flow V.sub.2 in the pilot
control line 365 is at V.sub.P, the un-occluded flow rate.
[0084] Pressure P.sub.2 remains relatively constant at a pressure
P.sub.B because the element 341 provides for a constant pressure
drop from pressure P.sub.A. As noted above, pressure P.sub.C, which
is illustrated in FIG. 6, is a constant, as it is the predetermined
pressure required to actuate the valve 330. P.sub.C can be adjusted
by altering the internal valve actuation spring and/or diaphragm in
the valve 330.
[0085] Pressures P.sub.2 and P.sub.3 respond to occlusion and then
un-occlusion in the pilot control circuit 360 (pilot control line
365). At time t.sub.1, the pilot control circuit 360 is occluded,
and pressure P.sub.2 increases as the gas in the pilot control line
365 is no longer vented at the vent port 351. Pilot gas flow
V.sub.2 quickly reduces to zero because the pilot control line 365
is occluded. Pressure P.sub.2 increases until equal to P.sub.C at
time t.sub.2, at which time the valve 330 is actuated and opens to
allow the primary gas to flow through the main gas circuit 350 at
the full inlet pressure P.sub.1. The pilot gas flow V.sub.1 begins
to quickly increase from 0 to V.sub.M, the un-occluded flow rate,
at t.sub.2+.DELTA.t, where .DELTA.t is a small elapsed time after
t.sub.2. The pressure P.sub.2 continues to increase until it
reaches the inlet pressure P.sub.1 (P.sub.A) at time t.sub.3, at
which time the pressure drop across the valve 330 is 0 psi. P.sub.2
remains at P.sub.1 (P.sub.A) and V.sub.1 remains at V.sub.m while
the pilot control circuit 360 is occluded.
[0086] At time t.sub.4, the pilot control circuit 360 is
un-occluded and begins to vent. The pilot gas flow V.sub.2 quickly
increases to V.sub.P. The pressure P.sub.2 begins to decrease and
continues to do so through time t.sub.5, until it reaches P.sub.C
at which time the valve 330 deactivates and closes, and the flow
V.sub.1 precipitously decreases to 0. The pressure P.sub.2
continues to decrease until it settles back at its initial pressure
P.sub.B at time t.sub.6. When vented, the pressure P.sub.2 drops
enough to allow the main valve 330 to close but does not drop to
atmospheric pressure P.sub.atm due to the residual constant flow in
the pilot control circuit 360 and the length of the pilot control
circuit 360.
[0087] Also illustrated in FIG. 7A is a plot of pressure P.sub.3 at
the vent port 351 and at the end 122 of the main gas line 355. The
plot of P.sub.3 is also approximately similar to the pressure after
the flow reduction element 341 if the pilot control circuit 360
were held at atmospheric pressure. For purposes of the following
discussion, the pressure P.sub.2 just after the flow reduction
element 341 in the pilot control circuit 360 when held at
atmospheric pressure is designated as P.sub.2'.
[0088] The plot of P.sub.3 is now described with the understanding
that P.sub.3 is approximately the same as P.sub.2'. Pressure
P.sub.3 is initially at atmospheric pressure, P.sub.atm. At time 1,
the pilot control circuit 360 is occluded, and pressure P.sub.3
increases as the gas in the pilot control line 365 is no longer
vented at the vent port 351. Pressure P.sub.3 increases until equal
to the threshold pressure P.sub.C at time t.sub.7, The pressure
P.sub.3 continues to increase until it reaches P.sub.1 (P.sub.A) at
time t.sub.8. P.sub.3 remains at P.sub.1 (P.sub.A) while the pilot
control circuit 360 is occluded. At time, t.sub.4, the pilot
control circuit 360 is un-occluded and begins to vent, and the
pressure P.sub.3 begins to decrease and continues to do so through
time t.sub.5 when the valve 330 deactivates and closes. The
pressure P.sub.3 continues to decrease until it settles back at its
initial pressure P.sub.atm.
[0089] FIGS. 7A and 7B show that a pilot control circuit 360 which
maintains a residual pressure P.sub.B higher than atmospheric
pressure P.sub.atm, will actuate the valve 330 and start the flow
V.sub.1 of main gas in the main gas circuit 350 more quickly than a
system maintained at P.sub.atm. The actuation time for the valve
330 for the system 300, 600 having a residual pressure P.sub.B in
the pilot control circuit 360 higher than atmospheric pressure
P.sub.atm, is t.sub.2-t.sub.1. The time for V.sub.1 to go from 0 to
V.sub.M is t.sub.2+.DELTA.t-t.sub.1. The actuation time for the
valve 330 if the system 300, 600 were to have a residual pressure
P.sub.atm in the pilot control circuit 360 at the valve 330 would
be t.sub.8-t.sub.1. Exemplary values for t.sub.2+.DELTA.t-t.sub.1
and t.sub.8-t.sub.1 are 250 ms and 1250 ms, respectively. An
exemplary value for .DELTA.t is 25 ms. By maintaining the pilot
control circuit 360 with pressure P.sub.2 at a residual pressure
P.sub.B rather than at P.sub.atm and by minimizing flow volume
(dead volume) in the pilot control circuit 360, the time
t.sub.2-t.sub.1 for pressure charging in the pilot control circuit
360 and for actuation of the valve 330 is minimized.
[0090] As discussed above, the pilot control branch 360 desirably
causes quick response of the valve 330 to provide almost
instantaneous flow to the patient after activation by the user. The
pilot control circuit 360 also desirably uses minimal gas flow to
actuate the valve 330 circuit and vent minimal gas to the
environment when not activated. Conventional gas delivery circuits
allow constant full, high-volume flow to the environment even when
such gas is not being using by a patient. Such waste is not
acceptable and is costly. The gas control unit 110 greatly reduces
such waste.
[0091] In an exemplary embodiment, the reduced flow and quick
response in the pilot control circuit 360 is accomplished by use of
a small flow orifice in the element 341 to restrict and lower flow
rate and volume in the pilot control circuit 360. Further, small
bore tubing with minimal wall pliancy is used in the portions
320A-D of the pilot control branch 320 and in the pilot control
line 365 to allow for a minimal flow area (cross section) and a
minimal dead volume to provide for quick actuation of the gas
sparing valve 330 when desired.
[0092] In addition, allowing a continuous small positive flow in
the pilot control circuit 360 at all times minimizes the response
time even further since, when occluded while having an initial
positive flow, the pilot control circuit 360 is already almost
fully charged with gas, as shown in FIG. 7A, and, thus, the
internal flow V.sub.2+in the pilot control circuit 360 will be
almost immediately directed into the gas sparing valve 330 upon
occlusion, thereby building enough back pressure, quickly, to
activate the gas sparing valve 330. In an exemplary embodiment,
under such conditions, patient flow V.sub.1 to a patient wearing
the mask 130 is initiated in fewer than 500 milliseconds. In
another exemplary embodiment, patient flow V.sub.1 is initiated in
about 250 milliseconds or less.
[0093] As shown in FIGS. 7A and 7B, by maintaining the pilot
control circuit 360 fully charged or nearly fully charged, response
time is reduced compared to conventional systems. Should the pilot
control circuit 360 be evacuated with no positive pressure or flow,
the circuit 360 would be at atmospheric pressure P.sub.atm and
would require time to fill and fully charge once flow was applied
and the circuit 360 occluded. This charge time significantly delays
system activation and renders use of the system 100 not desirable.
Since the gas sparing valve 330 requires a minimum threshold
pressure P.sub.C to activate, the closer the pilot control circuit
360 is maintained to this minimum threshold pressure P.sub.C, the
quicker activation of the valve 330 occurs when the pilot circuit
330 is occluded and the full pilot pressure P.sub.A reached.
[0094] Separate gas sources for the main gas circuit 350 and the
pilot control circuit 360 are not practical in a modular portable
system with minimal complexity. Thus, the system 300 is designed so
that the pilot control gas, the gas within the pilot control
circuit 360, is sourced from the same place as the system gas (also
referred to herein as the "primary gas" or "patient gas"), the gas
within the main gas circuit 350 (also referred to herein as the
"primary gas circuit 350").
[0095] Because the system 300 uses a common gas source for both the
primary and pilot gas flow, means to stop the loss of pilot gas
flow and pressure upon activating the gas sparing valve 330, until
desired by the operator, is desirably implemented. Should no means
be provided to maintain the required pressure in the pilot control
circuit 360 to hold the main valve 330 open, the main valve 330 may
begin to oscillate between an open and closed position as the
pressure P.sub.2 in the pilot control branch 320 fluctuates down
and then up as the main valve 330 opens and then closes,
respectively. This may result in gas flow in the main gas line 355
oscillating between flow and no flow in a manner not desired by the
operator.
[0096] To reduce or eliminate oscillation of the valve 330, the
system 300 comprises a check valve 340, which is designed to
eliminate backflow in the pilot branch 320 if there is a shift in
the pressure differential across the element 341 when the gas
sparing valve 330 opens, this shift in pressure differential would
reverse the flow direction of gas in the pilot branch 320. The
check valve 340 is used to lock and maintain pressure in the pilot
branch 320 once a pressure level has been established assuming no
gas is then allowed to escape from the opposite end of the branch
320, i.e., via the vent port 351. Thus, by placing a check valve in
the pilot control circuit 360 before the flow reduction element
341, when the outlet switch/valve 125 is occluded by the operator
and the pilot control circuit 360 is pressurized, any drop in
pressure on the inlet side of the check valve 340, which may occur
upon the main valve 330 opening, will not cause a pressure drop in
the pilot control circuit 360. Thus, the main valve 330 remains
open and does not oscillate between open and closed. Without the
check valve 340, any undesired (uncontrolled) loss of pressure in
the main gas circuit 350 might cause the main valve 330 to close
prematurely in an uncontrolled manner or to oscillate between open
and closed due to pressure fluctuations in the pilot control
circuit 360. Both premature closing of the main valve 330 and
uncontrolled oscillation of the main valve 330 between open and
closed are undesirable.
[0097] Referring now to FIGS. 8A and 8B together, there is
illustrated operation of an exemplary embodiment of the pilot air
flow control switch 125 disposed within a handle 800, in accordance
with an exemplary embodiment of the present invention. FIG. 8A
illustrates the switch 125 in an open position A. FIG. 8B
illustrates the switch 125 in a closed position B. As illustrated
in FIGS. 8A and 8B, the handle 800 is connected to a second end 122
of an exemplary embodiment of the disposable breathing circuit 120,
generally designated as 120' in FIGS. 8A and 8B. The handle 800 may
be permanently or removably attached to the disposable breathing
circuit 120. FIG. 8C illustrates various views of an exemplary
embodiment of the disposable breathing circuit 120', in accordance
with an exemplary embodiment of the present invention.
[0098] The disposable breathing circuit 120' illustrated in FIGS.
8A-8C differs from the disposable breathing circuit 120 because the
disposable breathing circuit 120' does not include the switch 125
or the vent 351. Instead, those components are disposed within the
handle 800 illustrated in FIGS. 8A and 8B. Thus, the main gas line
355 extends through the disposable breathing circuit 120' from the
first end 121 to the second end 122, which second end 122 is
connected to a first end 821 of the handle 800. The pilot gas line
365 extends through the disposable breathing circuit 120' from near
the first end 121 to near the second end 122, as seen best in FIG.
8C.
[0099] In the embodiment of the handle 800 illustrated in FIGS. 8A
and 8B, the pilot air flow control switch 125 is a pliant membrane
810 disposed over a pilot control orifice 820. The switch 125 and
specifically the pliant membrane 810, when in position A, does not
occlude the pilot control orifice 820 and when in position B, does
occlude the orifice 820. In an alternative embodiment, a rigid flow
switch could replace the pliant member 810 and perform the same
function.
[0100] The handle 800 allows the user to hold the mask 130 against
the patient's mouth and nose. The handle 800 comprises a bend 830
and an end 822 to which the mask 130 is attached. At the second end
123 of the pilot control line 365, the pilot control line 365
comprises a bend 825, which connects the pilot control line 365 to
a riser or port 835 which opens to atmosphere at the pilot control
orifice 820.
[0101] As illustrated in FIG. 8A, when the pilot air flow control
switch 125 is in the open position A, pilot gas 840 flows through
the pilot control line 365, around the bend 825, up the riser or
port 835, and through the pilot control orifice 820. The pilot gas
840 then passes through an exhaust port 845 and is exhausted
through the vent port 351. Because pilot gas 840 is vented through
the vent port 351, the gas sparing valve 330 is deactivated and
does not allow main gas 850 to flow through the main gas line
355.
[0102] As illustrated in FIG. 8B, when the pilot air flow control
switch 125 is in the closed position B, i.e., when the pliant
member 810 is depressed, the pilot control orifice 820 is occluded
by the membrane 810, and pilot gas 840 is not vented through the
vent port 351. The lack of pilot gas flow is labeled as 840' in
FIG. 8B. Because there is no pilot gas flow 840', the gas sparing
valve 300 is actuated and main gas 850 flows through the main gas
line 355, out the second end 822 of the handle 800, and through the
mask 130. Upon release of the pliant member 810, the pilot gas 840
vents, de-actuating and closing the gas sparing valve 330 and
stopping flow of the main gas 850 to the patient mask 130.
[0103] FIGS. 8A-8C illustrate that the pilot control line 365 is
extended through the breathing circuit 120' to the end 122 (or near
to the end 122) of the breathing circuit 120, and the handle 830 is
attached to the end of the breathing circuit 120. It is to be
understood that in an exemplary embodiment, the breathing circuit
120 may be modified so that the handle 830 is disposed at the end
122 of the breathing circuit 120.
[0104] Referring now to FIG. 2, there is illustrated a block
diagram of an alternative system, generally designated as 200, for
delivering gas to a patient via an alternative embodiment of the
patient mask 130, generally designated in FIG. 2 as 130', in
accordance with an exemplary embodiment of the present invention.
The system 200 comprises all of the elements of the system 100,
except for the patient mask 130, but additionally includes
functionality for a second gas delivery mode, as described below,
namely in a continuous positive airway pressure (CPAP) gas delivery
mode where a continuous low pressure, low flow-rate gas is required
after resuscitation.
[0105] The system 200 comprises a gas control unit 210, rather than
the gas control unit 110. The gas control unit 210 comprises the
elements 111-119, though used in the system 200 capable of a CPAP
gas delivery mode, as is now described. Accordingly, the gas
control unit 210 additionally comprises a CPAP flow rate control
212 to allow the user to select a desired CPAP flow rate and a
mode-selection switch 214 for selection between the CPAP mode and
the gas-sparing resuscitation mode of the system 100.
[0106] The mask 130' used with the system 200 differs from the mask
130 used with the system 100. The mask 130' incorporates a CPAP
exhalation port 216, which allows the user of the mask 130' to
exhale when the system 200 is operating in the CPAP gas delivery
mode. The mask 130' is described in more detail below with respect
to FIG. 17.
[0107] An exemplary view of the external of the gas control unit
210 is illustrated in FIG. 21, in accordance with an exemplary
embodiment of the present invention. The various components of the
gas control unit 210 illustrated in FIG. 2 and described above are
mounted to an enclosure 2100 of the gas control unit 210. Attached
to the enclosure 2100 is a handle 2110 for carrying the gas control
unit 210.
[0108] Referring now to FIG. 4, there is illustrated a block
diagram of a gas sparing circuit 400 comprising the gas control
unit 210, an embodiment of the disposable breathing circuit 120,
generally designated in FIG. 4 as 120', and an alternative
embodiment of the patient mask 130', generally designated in FIG. 4
as 130'', in accordance with an exemplary embodiment of the present
invention. The gas sparing circuit 400 uses all of the components
illustrated in FIG. 2 and additional components, as illustrated in
FIG. 4. The gas sparing circuit 400 incorporates the primary branch
310 and the pilot control branch 320 of the gas sparing circuit 300
in the resuscitation side 410 of the gas sparing circuit 400. The
gas control unit 210 additionally comprises a CPAP circuit or
branch 430 in a CPAP side 420 of the gas sparing circuit 400. The
CPAP circuit or branch 430 comprises portions or lines 430A-430B.
The CPAP circuit or branch 430 is a continuous flow circuit when in
use as there is no gas sparing control on this side.
[0109] The resuscitation side 410 comprises the primary branch 310
and the pilot control branch 320 of the gas sparing circuit 300,
which branches operate similarly in the gas sparing circuit 400 to
those in the gas sparing circuit 300. The primary branch 310 and
the pilot control branch 320, however, are modified slightly for
use in the gas sparing circuit. First, the portions 310A and 320A
are not directly connected to the flow meter 113 with flow control
115 via the inlet line 305, as they are in the gas sparing circuit
300. Instead, the inlet line 305 is directly connected to the
mode-selection switch 214. Second, the portion 310e of the primary
branch 310 in the gas sparing circuit 400, while still directly
connected to the main air port 117, is also connected to the
portion 430B of the CPAP branch 430. Third, the primary branch 310
may include a check valve 440A in the portion 310B or a check valve
440B in the portion 310D to further restrict back flow into the
resuscitation side 410 when the gas sparing circuit 400 is
operating in CPAP mode.
[0110] The CPAP branch 430 comprises the portion 430A, which
couples the mode-selection switch 214 to the CPAP flow control
valve 212 as needed. The portion 430B couples the CPAP flow control
valve 212 to the portion 310E of the primary branch 310. The
mode-selection switch 214 is coupled to the flow meter 113 and flow
control 115 via a portion 440. The mode-selection switch 214 allows
the operator to select for CPAP continuous air delivery (CPAP mode)
through the primary gas line 355 via the CPAP branch 430 or to
select for pilot-controlled primary gas delivery (resuscitation
mode) through the primary gas line 355 via the resuscitation side
410, and the flow control valve 212 allows the operator to select
the rate of gas flow in the CPAP branch 430.
[0111] In an exemplary embodiment, the portion 430B includes a
pressure relief valve 435A and/or a check valve 435B. The pressure
relief valve 435A provides venting for overpressure in the CPAP
branch 430, and the check valve 435B prevents backflow in the CPAP
branch 430. In another exemplary embodiment, CPAP Branch portion
430B could be connected to Main branch portion 310B allowing the
pressure relief valve 118 to be disposed downstream downstream of
the connection with the portion 430B. In such embodiment, the
pressure relief valve 118 provides venting for overpressure in
either the CPAP branch 430 or the primary branch 310.
[0112] Separate flow control valves in the CPAP branch 430 and the
main gas branch 310 are contemplated. These valves are,
respectively, the flow control valves 212 and 115. In an exemplary
alternative embodiment, the flow control valve 212 is removed, and
the flow control valve 115 is used to regulate the rate of gas flow
in the main gas branch 310 and the CPAP branch 430. In another
exemplary alternative embodiment, the flow control valve 115 is
disposed in the portion 310A downstream of the mode-selection
switch 214 to control flow in the primary branch 310, and the flow
control valve 212 is disposed in the CPAP branch 430 to control
CPAP flow. In yet another exemplary alternative embodiment, check
valves 440A and/or 440B are contemplated to stop backflow in the
primary branch 310. The check valves 435B, 440A, and 440B also
prevent cross flow between the CPAP branch 430 and the primary
branch 310.
[0113] The mask 130'' differs from the mask 130' because the mask
130' includes the switch 125 and the vent 351, respectively
designated as 125' and 351' in FIG. 4. It is to be understood that
the mask 130'' incorporates the CPAP exhalation port 216 used in
the mask 130'. This port is open when in CPAP mode but is closed
when in resuscitation mode. In an exemplary alternative embodiment,
the disposable breathing circuit 120 and the mask 130' are used
with the gas sparing circuit 400. In another exemplary alternative
embodiment, the handle 800 may be attached to the disposable
breathing circuit 120' and the mask 130' if used with the gas
sparing circuit 400 or may be incorporated into the mask 130'' if
used with the gas sparing circuit 400.
[0114] Referring now to FIG. 9, there is illustrated an exemplary
alternative embodiment of the gas sparing circuit 300, generally
designated in FIG. 9 as 900, in accordance with an exemplary
embodiment of the present invention. The gas sparing circuit 900
uses all of the components illustrated in FIG. 3, modified as
described below, and additional components, as illustrated in FIG.
9. The gas sparing circuit 900 incorporates the main gas branch 310
and the pilot control branch 320, as modified as a pilot control
branch 320'. In another exemplary embodiment, a CPAP branch, such
as the CPAP branch 430 of FIG. 4, could also be added to the gas
sparing circuit 900 to add CPAP functionality.
[0115] The pilot control branch 320' comprises the elements of the
pilot control branch 320 of the pilot control branch 320 and
additionally a pneumatic timer control 910 configured to control
the on-time of the main gas sparing valve 330. The portion 310D of
the pilot control branch 320 is replaced by portions 320D' and 920A
and 920B. If used to control the on-time of the main gas sparing
valve 330, the pneumatic timer control 910 is a normally open
valve.
[0116] The portion 320D' couples an output 992 the pneumatic timer
control 910 to the control side 333 of the gas sparing valve 330.
The portion 920A couples the portion 320C to an input 911 of the
pneumatic timer control 910. The portion 920B couples the portion
320C to a timer unit 993.
[0117] Operation of the gas sparing circuit 900, with on-time
control, is now described. Operation begins with the pilot control
circuit 360 in an un-occluded state, the gas sparing valve 330
closed, and pilot gas at pressure PB is applied to the control side
333 of the gas sparing valve 330 through the pneumatic timer
control 910, which is in an open state. Upon closure or occlusion
of the pilot control line 365, the gas sparing valve 330 opens, as
described above with respect to FIGS. 3, 6, and 7, and pressure at
the timer unit 993 increases. When the pressure at the time unit
993 reaches a threshold pressure, a counter within the timer unit
993 starts and counts until it reaches an activation time. After
the activation time of the timer 993 is reached, the timer 993
cycles and closes a valve in the pneumatic timer 910 and vents the
pilot connection 320D' of the gas sparing valve 330 via a vent 994,
thereby causing the gas sparing value 330 to close and main flow
through the main gas line 355 to stop. The cycle may repeat after
the pilot control line 365 is vented, which causes the timer unit
993 to reset. In this modality, the provision of primary gas
through the gas sparing valve 330 for each breath is triggered by
the user occluding the pilot control line 365. Thus, re-occlusion
of the pilot control line 365 starts each resuscitation breath.
Also, in this modality, the user could deliver inhalation breaths
in succession without allowing for complete exhalation, if desired,
since any venting of the pilot line would reset the timer valve 993
and allow the cycle to restart very quickly. Exhalation is
accomplished as described herein, such as via exhaust ports in the
mask 130 or 130' or via exhaust ports in a hand piece to which the
mask 130 or 130' is connected, such as the exhaust ports 1226 in
the hand piece 1200 described below.
[0118] In this way, the gas sparing circuit 900 controls the amount
of time gas is provided via the main gas line 355 and thereby
controls the inhalation time of the patient using the gas sparing
circuit 900. The activation time can be adjusted from fractions of
a second to several seconds as desired by the user. The user may
set the activation (breath) time of the timer unit 993 to be
between 0.5 to 3 seconds. Desirable breath time is approximately
1.0 to 1.5 second for inhalation breath flow followed by 1.0 to 3.0
seconds of vent or exhalation time.
[0119] Should the user desire automatic continuous control of the
inhalation time followed by automatic control of the exhalation
time, two pneumatic timers could be used in an exemplary embodiment
of the gas sparing circuit 900, generally designated as 1000 in
FIG. 10, in accordance with an exemplary embodiment of the present
invention. The gas sparing circuit 1000 uses all of the components
illustrated in FIG. 3, modified as described below, and additional
components, as illustrated in FIG. 10. The gas sparing circuit 1000
incorporates the primary branch 310 and the pilot control branch
320', as modified as a pilot control branch 320''. In another
exemplary embodiment, a CPAP branch, such as the CPAP branch 430 of
FIG. 4, could also be added to the gas sparing circuit 1000 to add
CPAP functionality.
[0120] The pilot control branch 320'' comprises the elements of the
pilot control branch 320' of the gas sparing circuit 900 and
additionally two pneumatic timer controls 1010 and 1020. In this
configuration, the first timer control 1010 controls the on
(inhalation) time (the time during which the gas sparing valve 330
is open) and the second timer control 1020 controls the off
(exhalation) time (the time during which the gas sparing valve 330
is closed).
[0121] In the pilot control branch 320'', the element 341 is
coupled to an inlet 1011 of the first timer 1010 via a portion
1030A. An outlet 1012 of the first timer control 1010 is coupled to
an inlet 1021 of the second timer control 1020 via portion 1030D.
An outlet 1022 of the second timer control 1020 is coupled to a
timer 1013 of the first timer control 1010 via a portion 1030B.
[0122] The control side 333 of the gas sparing valve 330 is coupled
to the outlet 1012 and the inlet 1021 via a portion 1030E which
also connects to the outlet port 112. The portion 1030E is also
coupled to a timer 1023 of the first timer control 1020 via a
portion 1030F.
[0123] Operation of the gas sparing circuit 1000 is now described.
Operation begins with the pilot control circuit 360 in an
un-occluded state, the gas sparing valve 330 closed, and pilot gas
at pressure P.sub.B is applied to the control side 333 of the gas
sparing valve 330 through the pneumatic timer control 1010, which
is in an open state. The pneumatic timer control 1020 is in a
closed state, and the line 1030B has been vented. Upon closure or
occlusion of the pilot control line 365, the gas sparing valve 330
opens, as described above with respect to FIGS. 3, 6, and 7, and
primary gas is provided to the patient via the primary circuit 350.
At the same time, pressure at the timer unit 1023 increases. When
(almost instantaneously) the pressure at the timer unit 1023
reaches a threshold pressure, a valve within the pneumatic timer
control 1020 closes and a counter within the timer unit 1023
starts. When the counter within the timer unit 1023 reaches an
activation time, the timer 1023 cycles a valve in the pneumatic
timer control 1020 to an open state and vents the pilot circuit
360.
[0124] Because the valve in the pneumatic timer control 1020 is
opened, pilot gas is allowed to pass from the inlet 1021 to the
outlet 1022 and to the timer 1013 of the pneumatic timer control
1010 via the line 1030B. Pressure at the timer unit 1013 increases.
When (almost instantaneously) the pressure at the timer unit 1013
reaches a threshold pressure, a valve within the pneumatic timer
control 1010 closes, thereby shutting down flow of the pilot gas
from the inlet 1011 to the outlet 1012 of the pneumatic timer
control 1010. Because the pneumatic timer control 1020 is in an
open state and is venting the pilot circuit 360, the gas sparing
valve 330 closes. This stops the flow of gas to the patient and
allows exhalation to occur. This discontinuation of pilot flow also
resets timer 1020.
[0125] A counter within the timer unit 1013 starts and counts until
it reaches an activation time. After the activation time of the
timer 1013 is reached, the timer 1013 cycles the valve in the
pneumatic timer 1010 to an open state to restart the flow of pilot
gas from the inlet 1011 to the outlet 1012, which applies pilot gas
to the pneumatic timer control 1020 to close the valve therein. At
the same time, the gas sparing valve 330 opens, and primary gas is
again provided to the patient via the primary circuit 350. Once the
exhalation cycle is started, i.e. when the valve in the pneumatic
timer 1010 closes, the user cannot deliver another inhalation
breath until the exhalation cycle is fully completed. This ensures
a full exhalation cycle is completed.
[0126] Operation of the gas sparing circuit 1000 cycles through the
above-described process as long at the pilot air flow control
switch 125 is closed. When the user releases the switch 125, the
cycle stops. Additionally a mechanical or electrical latch or
closure device can be added to the gas sparing circuit 1000, at the
pilot control switch 125, that would allow for mechanical latching
(closure) of the switch 125 in the closed position thus allowing
for continued ventilation of the patient where the user would not
have to hold the switch 125 in the closed position with his or her
hand. This latch could be switched in and out to hold the pilot
control switch 125 in the closed position or allow it to be in the
open position for manual, finger-based activation.
[0127] In this configuration, once the pilot control line 365 is
occluded, the system 1000 automatically cycles between inhalation
(gas sparing valve 330 open to provide gas in the main gas line
355), and exhalation (gas sparing valve 330 closed). The user may
set the ventilation breath time by setting the activation time of
the timer unit 1023 to be between 0.5 to 3 seconds. Desirable
breath time is approximately 1.0 to 1.5 second for inhalation
breath flow. The user may set the exhalation time by setting the
activation time of the timer unit 1013. Desirable exhalation time
is approximately 1.0 to 3.0 seconds for exhalation breath flow.
[0128] Although FIGS. 9 and 10 illustrate using pneumatic time
controls, other embodiments using electro-pneumatic controls or
timer-based triggers are contemplated. In a gas-sparing circuit
incorporating a timer-based trigger, the user activates the trigger
to occlude the pilot control line 365 and activate the gas sparing
valve 330. Then, within the trigger, a mechanical, electrical, or
pneumatic-mechanical switch cycles over the desired time period and
opens the pilot control line 365 to atmosphere, thereby closing the
gas sparing valve 330, stopping primary airflow.
[0129] Referring now to FIG. 11A, there is illustrated a side
cross-sectional view of an exemplary embodiment of a
pneumatic-mechanical timer-based trigger 125' and to FIG. 11B,
there is illustrated a top view revealing internal details of the
trigger 125', in accordance with an exemplary embodiment of the
present invention. The trigger 125' may be substituted into the gas
sparing circuits 300 and 400 to replace the trigger 125.
[0130] The trigger 125' comprises a housing 1101 in which a trigger
handle 1102 is slidably disposed. The trigger handle 1102 is
connected to a guide rod 1107 which passes through slots 1103 and
1104 in the housing. The guide rode 1107 may slide from one end of
the slots 1103 and 1104 to the other as the trigger handle 1102
slides within the housing 1101. The trigger handle 1102 is coupled
to a plunger which terminates in a soft diaphragm 1106. Disposed on
the plunger between the trigger handle 1102 and the diaphragm 1106
is a spring 1114.
[0131] The pilot control line 365 pierces a first end 1121 of the
housing 1101 and terminates within an interior space 1120 of the
housing 1101 formed between the housing 1101 and the diaphragm
1106. The interior space 1120 vents to the outside of the housing
1101 via vents 1111. Disposed at a second end 1131 of the housing
1101 is a plunger 1130, which is attached to the trigger handle
1102. The housing 1101 forms an interior space 1140 between the
plunger 1130 and the second end 1131 of the housing 1101. The
interior space 1140 vents to the outside of the housing 1101 via a
one-way diaphragm valve 1112. Also disposed in the housing 1101 at
the second end 1131 is a vent valve 1113, which is used to set vent
time.
[0132] Disposed on the housing of the housing 1101 is a timer
adjuster nut 1108 for adjusting the timer. Disposed around the
housing 1101 between the nut 1108 and the trigger handle 1102 is a
spring 1110. A stop 1109 provides a stop for lateral movement of
the trigger handle 1102.
[0133] Operation of the trigger 125' is now described. The user
pulls the trigger 125' toward the first end 1121, thereby pushing
the soft diaphragm 1106 against the end of the pilot control line
365 and compressing the spring 1114 between the diaphragm 1106 and
the trigger handle 1102. The spring 1114 provides for tactile
feeling in the trigger 125'. Once the pilot control line 365 is
occluded, the gas sparing valve 330 opens allowing primary
flow.
[0134] When the trigger handle 1102 is pulled, in addition to
advancing the soft diaphragm 1106, the trigger handle 1102 pulls
the plunger 1130 away from the second end of the housing 1101. As
the trigger handle 1102 and plunger 1130 advance, the chamber fills
1140 with air via the one way diaphragm valve 1112. When the
trigger handle 1102 is released either by the user or by design via
an automatically disengaging trigger activator, the spring 1110
applies force on the trigger handle 1102 to move the plunger 1130
back to its initial position. Since the chamber 1140 is now filled
with air, the pressure in the chamber 1140 resists movement of the
plunger 1130. Air from the chamber 1140 vents with movement of the
plunger 1130. The adjustable vent valve 1113 allows the rate of the
venting of the chamber 1140 to be controlled.
[0135] As the air in the chamber 1140 vents through the vent valve
1113, the plunger 1105 moves toward its original position and the
pressure of the spring 1114 on the soft diaphragm 1106 begins to
reduce. When the plunger 1105 has travelled a sufficient distance,
the force of the spring 1114 on the diaphragm 1106 will be low
enough such that the pressure in the pilot control line 365, which
is 50 psi, will create enough force on the rear surface of the soft
diaphragm 1106 to force the diaphragm 1106 open. The pilot control
line 365 vents through the chamber 1120 and the vents 1111 to the
outside of the housing 1101. As the pressure in the pilot control
line 365 reduces past pressure PC, the gas sparing valve 330 closes
and air flow in the main gas line 355 stops. The spring 1110 pushes
the trigger handle 1102 laterally until the trigger handle 1102
comes into contact with the stop 1109, at which time the plunger
1130 stops moving.
[0136] Thus, a timer circuit is created by the timer-based trigger
125'. The time duration of air flow through the main gas line 355
is controlled by the return travel distance of the trigger handle
1102 and the speed of the plunger 1130. Adjustment of the nut 1108
adjusts travel of the trigger handle 1102 to allow adjustment of
the timer circuit of the timer-based trigger 125'. Further, the
vent time of the chamber 1140 is adjustable by the vent valve 1113
to further provide for adjustment of the timer circuit of the
timer-based trigger 125'.
[0137] A patient using the CPAP system 200 may attempt to breathe
in an amount of air that is larger than baseline air flow provided
by the CPAP side 420 of the system 200. Under these conditions, a
means is desirably provided to allow for this larger air quantity
to enter the system 200.
[0138] In conventional CPAP systems, the masks have special valves
that allow for this larger air quantity. Although use of a special
mask is possible in the CPAP system 200, it is not optimal. In
addition, if spontaneous breathing were to occur during normal
resuscitation where a CPAP mask in a conventional CPAP system
cannot be used, the patient would not be able to draw in the extra
air desired.
[0139] In conventional bag and mask systems, a valve within the
rear of the bag system allows for air flow should the patient begin
to breathe. However, these devices cannot provide CPAP
functionality, and they have no flow and pressure controls. In the
system 200 or 400 described above, because such systems are closed
or could be very remote from the patient, a valve in the system
that would allow for spontaneous breathing would be ineffective
because the breathing circuit 120 would be too long to allow for
minimal flow restriction. Thus, in order to minimize the
restriction to a spontaneous breath with the system 200 or 400, it
is desirable to provide a spontaneous breath valve system as close
to the patient as possible. However, this valve desirably remains
closed during resuscitation and CPAP positive air flow and only
opens when an air flow, larger than the resuscitation or CPAP flow,
is demanded by the patient via inhalation breath volume.
[0140] Referring now to FIG. 12, there is illustrated an exemplary
embodiment of the mask connection 370, generally designated as 1200
in FIG. 12, in use with a valve system 1250 to accommodate a
patient's ability to draw in extra air if desired, in accordance
with an exemplary embodiment of the present invention. The mask
connection 1200 comprises a housing 1210, a rotating outlet port
1220, and the valve system 1250. The housing 1210 comprises, at a
first end 1212, a gas inlet 1211, which is connected to the second
end 122 of the disposable breathing circuit 120, and, at a second
end 1220, an outlet 1222, which is connected to the mask 130. In an
exemplary embodiment, the housing 1210 is a two-piece housing
comprising a first portion 1210A and a second portion 1210B. The
valve system 1250 allows the same mask 130 (illustrated in FIGS.
3-4) to be used for either respiration or CPAP and allows for
spontaneous breathing along with the traditional non-rebreathing
function.
[0141] The valve system 1250 comprises a unidirectional valve 1260
and a two-way valve diaphragm 1270 comprising a duck bill valve
1272, and a diaphragm 1275 connected to the duck bill valve 1272.
In the exemplary embodiment illustrated in FIG. 12, the duck bill
valve 1272 and the diaphragm 1275 are a flexible unitary structure.
It is to be understood that other embodiments in which the duck
bill valve 1272 is separate from the diaphragm 1275 are
contemplated.
[0142] The unidirectional valve 1260 is in a normally closed state
in which it seals breath ports 1265 in the housing 1210. Disposed
inside of the housing 1210 around the unidirectional valve 1260 is
a seal ring 1264, which is configured to provide a seal against the
two-way valve diaphragm 1270 during patient exhalation. A view of
an alternative embodiment of the unidirectional valve 1260 is
illustrated in FIG. 12A.
[0143] The rotating outlet port 1220 is rotatably attached to the
housing 1210. The outlet port 1220 is configured to rotate relative
to the housing 1210 to provide for patient comfort during use. A
portion of the rotation outlet port 1220 adjacent to the two-way
valve diaphragm 1270 is a seal rim 1224 which is configured to seal
against the two-way valve diaphragm 1270 during patient
inhalation.
[0144] Disposed in the housing adjacent the rotating outlet port
1220 are exhaust ports 1226 and an exhaust seal 1228 for allowing
one-way operation of the exhaust ports 1226. In an exemplary
embodiment, the exhaust ports 1226 and the exhaust seal 1228 are
disposed in the second portion 1210B of the housing 1210.
[0145] Operation of the mask connection 1200 is now described. In
the mask connection 1200, when air flows into the inlet 1211 in the
resuscitation or CPAP mode, it flows through the two-way inlet
valve diaphragm 1270, via the duck bill valve 1272, which opens
under positive inhalation air flow, to the outlet 1222. This air
also forces the diaphragm 1275 of this valve diaphragm 1270 against
the seal rim 1224.
[0146] Air flows to the mask 130 during gas delivery or when the
patient inhales. During patient exhalation, the Duck bill portion
1272 of the two-way valve diaphragm 1270 closes and the exhaled air
forces the diaphragm portion 1275 off the seal 1224 and against the
seal rim 1264. The outlet 1222 is thereby sealed from the interior
space 1211 of the housing 1210. So sealed, the outlet 1222 directs
the patient's exhaled air in from the outlet 1222 around the seal
rim 1224 and through the exhaust ports 1226 and past the exhaust
seal 1228. The exhaust seal 1228 is a one-way exhaust seal that
serves as a backup for the diaphragm seal ring 1224 during
inhalation to ensure that no air can reverse flow into the exhaust
ports 1228.
[0147] The unidirectional valve 1260 allows for the patient to
breathe spontaneously. Should the patient spontaneously breathe or
inhale a volume that is higher than that being delivered at the
inlet 1211 of the mask connection 1200, the spontaneous breath
valve 1260 opens and allows additional air to flow to the patient
through the spontaneous breath ports 1265. This valve 1260 only
stay opens if the volume demanded at the output 1222 is higher than
the volume at the inlet 1211, i.e., a negative pressure at the
inlet 1212 is developed. As soon as the volume demanded at the
output 1222 drops below the volume provided at the inlet 1212, the
valve 1260 closes and seals the spontaneous breath ports 1265.
Thus, the spontaneous breath valve 1265 remains closed during all
gas inlet 1212 function unless the patient creates an excess
demand. Because the valve system 1250 is proximal to the patient,
minimal restriction to airflow is created. This restriction is
designed to be no more than 5cmH.sub.2O in negative pressure. Thus,
a single valve assembly 1250 breathing circuit can be used for both
direct resuscitation and for CPAP wherein spontaneous breathing
could occur.
[0148] Illustrated in FIG. 12B are exemplary side and top views of
the mask connection 1200 attached the second end 122 of the
disposable breathing circuit 120', in accordance with an exemplary
embodiment of the present invention. The pilot control line 365 is
shown unconnected at the first and second ends 121 and 122. It is
to be understood that the pilot control line 365 at the first end
121 of the disposable breathing circuit 120' may be connected to
the pilot control port 116 of the system 100, and the second end
122 of the disposable breathing circuit 120' may be connected to a
pilot connection point on a mask or mask connection, as described
herein. FIG. 12B illustrates a closer cross-sectional view of the
first end 121 of the disposable breathing circuit 120'.
[0149] Referring now to FIG. 13, there is illustrated a hand piece,
generally designated as 1300, in accordance with an exemplary
embodiment of the present invention. The hand piece 1300 may be
used in cooperation with a conventional mask or the mask of FIG. 17
described below.
[0150] The hand piece 1300 comprises a flexible frame 1310 which is
configured to fit over a conventional resuscitation mask. The hand
piece includes a hole 1320 through which the connection port of the
conventional mask passes. Positioned at a first end 1301 of the
hand piece 1300 is a pilot control switch 1340 coupled to a vent
1344 for venting a pilot circuit, such as the pilot circuit 360.
The switch 1340 and vent 1344 function similarly to the switch 125
and vent 315 illustrated in FIGS. 8A and 8B. A flexible elastomeric
switch cap 1342 is placed over the switch 1340 for operating the
switch 1340.
[0151] The switch 1340 is coupled to a pilot control line extension
tube 1330 at a first end 1331 of the tube 1330. Coupled to a second
end 1332 of the tube 1330 is a connector 1335 for connecting the
tube 1330 to other portions of the pilot control circuit 360.
[0152] A system 1400 in which the hand piece 1300 may be used is
illustrated in FIG. 14, in accordance with an exemplary embodiment
of the present invention. The system 1400 comprises the disposable
breathing circuit 120', an adapter 1401 connected to the end 122 of
the disposable breathing circuit 120', an optional capnometer 1410
coupled to the adapter 1401, and mask connection 1200 coupled to
the capnometer 1410. The mask 130 is connected to the mask
connection 1200 via the connection port 131.
[0153] The adapter 1401 comprises a positive end-expiratory
pressure (PEEP) control 1402 for regulating PEEP through the
adapter 1401. The adapter 1401 further comprises a pilot control
line 1404 that outputs via an output connection 1406 connected to
the luer 1335 and a main gas line 1408 that is connected to the
main gas line 355 of the disposable breathing circuit 120'.
[0154] As illustrated in FIG. 14, the hand piece 1300 is configured
to fit over the mask 130. The hole 1320 of the hand piece 1300 is
sized to accommodate the connection port 131 of the mask 130.
Activation of air flow through the mask 130 is achieved by
depressing the elastomeric switch cap 1342 which actuates the
switch 1340 to occlude the pilot control circuit 360, which in the
embodiment illustrated in FIG. 14 includes the pilot control line
365, the pilot control line 1404 and the pilot control line
extension tube 1330. The gas sparing valve 330 is thereby
opened.
[0155] An enlarged view of the pilot control switch 1340 is shown
in FIG. 13A, in accordance with an exemplary embodiment of the
present invention. The switch 1340 is constructed similarly to the
switch 125 illustrated in FIGS. 8A and 8B and operates
similarly.
[0156] As seen in FIG. 13A, the switch 1340 is formed by the
elastomeric membrane 1342 which is attached to the frame 1310 of
the hand piece 1300 over a chamber 1348. The end 1331 of pilot
control line 1330 is disposed within the frame 1310 and opens to
the chamber 1348 at an opening 1349. A seal ridge 1346 is disposed
around the opening 1349 of the pilot control line 1330.
[0157] When the elastomeric membrane 1342 is in the state shown in
FIG. 13A, i.e., when it is in a non-depressed state, pilot gas
passes through the pilot control line 1330, out the opening 1349,
through the air chamber 1348, and out the vent port 1344. Under
this condition, the gas sparing valve 330 is not activated and
there is no flow in the primary gas circuit 305. When the
elastomeric switch element 1342 is depressed against the seal ridge
1346, the pilot gas air flows out the vent 1344 is occluded,
thereby activating the gas sparing valve 330 and allowing primary
gas to flow through the primary gas circuit 350 until the
elastomeric switch element 1342 is released.
[0158] In addition to the hand piece 1300 described above, a simple
hand piece that could be used without a mask, and used with other
resuscitation apparatus such as an endotracheal tube, is
contemplated. Illustrated in FIG. 15 is an endotracheal tube hand
piece (also referred to herein as "endotracheal tube adapter")
1500, in accordance with an exemplary embodiment of the present
invention. The endotracheal hand piece 1500 is configured to be
used with the disposable breathing circuit 120'. The disposable
breathing circuit 120' differs from the disposable breathing
circuit 120 in that the disposable breathing circuit 120' does not
include the pilot control switch 125 or the vent 351. Instead, the
pilot control line 365 extends through the entire length of the
disposable breathing circuit 120' to the second end 122. The end
122 of the disposable breathing circuit 120' comprises an outlet
1510 of the pilot control line 365 and an outlet 1520 of the main
gas line 355.
[0159] The endotracheal hand piece 1500 comprises a first end 1501
comprising an inlet port 1530 and an inlet port 1540. The port 1540
is configured to receive the outlet port 1510 of the pilot control
line 365. The port 1540 is coupled to the pilot control switch 1340
and the vent 1344. The port 1530 is configured to receive the
outlet port 1520 of the main gas line 355. The port 1530
communicates with an endotracheal tube connection 1550 at a second
end 1502 of the endotracheal hand piece 1500. The switch 1340 is
operated as described above to control the main gas line 355. When
operated, the switch 1340 actuates the gas sparing valve 330 to
provide primary gas through the main gas line 355, to the port
1530, and to an endotracheal tube 1560 connected to the connection
1550.
[0160] Alternative exemplary embodiments of the hand piece 1300 are
illustrated in FIGS. 16A and 16B, in accordance with an exemplary
embodiment of the present invention. Illustrated in FIG. 16A is a
hand piece 1600A, which is, generally, a combination of the hand
piece 1300 and the mask connection 1200, in accordance with an
exemplary embodiment of the present invention. The hand piece 1600A
comprises a handle 1610, a body portion 1630, and a mask 1640. The
mask 1640 may be rotatably connected to the body portion 1630. The
body portion 1630 is connected to the handle 1610 by a pliant
section 1620, which allows for the handle 1610 to bend relative to
the body portion 1630.
[0161] The disposable breathing circuit 120' is connected to the
hand piece 1600A via a rotatable coupling 1640. The rotatable
coupling 1640 allows for the position of the disposable breathing
circuit 120' to be positioned for patient comfort when the mask is
installed on the patient. Activation of the gas sparing system is
by way of the elastomeric element 1340. It is to be understood that
the hand piece 1600A may be used in any of the systems for
delivering gas to a patient and gas sparing circuits described
herein.
[0162] Illustrated in FIG. 16B is a hand piece 1600B, which is
also, generally, a combination of the hand piece 1300 and the mask
connection 1200, in accordance with an exemplary embodiment of the
present invention. The hand piece 1600B comprises all of the
elements of the hand piece 1600A, with a few modifications. The
hand piece 1600B comprises an L-shaped handle 1610' rather than the
mostly vertical handle 1610 of the hand piece 1600A. In one
embodiment, the disposable breathing circuit 120' may be connected
to the rotating body portion 1630 of the hand piece 1600B. In
another embodiment, an end 1611 of the handle 1610' is configured
to receive the end 122 of the disposable breathing circuit
120'.
[0163] Referring now to FIG. 17, there is illustrated an exemplary
embodiment of the patient mask 130', in accordance with an
exemplary embodiment of the present invention. The patient mask
130' is used with a gas sparing circuit, such as the gas sparing
circuit 400 of the gas delivery system 400, in which both
resuscitation and CPAP gas delivery modes are desired. The mask
130' comprises the CPAP port 216 described above with respect to
FIG. 2. FIG. 17 illustrates the CPAP port 216 in further
detail.
[0164] The CPAP port 216 comprises a vent port 1700 comprising
valve housing 1702 integrated with the mask 130'. The valve housing
1702 is capped by a removable cap 1704, which is tethered to the
housing 1702 by a lanyard 1708. Disposed within the valve housing
1702 is a one-way valve 1706. When the mask 130' is used with the
system 200, and the system 200 is operating in resuscitation mode,
the cap 1704 is placed over the port 1700 to not allow
resuscitation gas to bypass the patient and exit the mask 130'.
When operating in CPAP mode, the cap 1704 is removed to allow
exhalation breath.
[0165] In the case that the mask 130' is used with the mask
connection 1200, exhalation through the ports 1226 is not possible
as the diaphragm 1275 is in the open position in the CPAP mode.
Thus, a second exhalation port is provided via the exhalation port
in the mask in FIG. 17. Thus, the vent port 1700 allows for an
exhalation breath along with inlet gas flow exhaust for pressure
relief within the mask 130' during CPAP mode so that the pressure
within the mask 130' during use is maintained at a controlled
level.
[0166] FIG. 18 illustrates another embodiment of a system,
generally designated as 1800, comprising the disposable breathing
circuit 120', the mask connection 1200, the mask 130, and the hand
piece 1300, in accordance with an exemplary embodiment of the
present invention. The connector 1335 of the hand piece 1300 is
connected to the second end 122 of the pilot control line 365 of
the disposable breathing circuit 120'. The first end 1212 of the
mask connection 1200 is connected to the second end 122 of the main
gas line 355 of the disposable breathing circuit 120', and the
second end 1222 of the mask connection 1200 is connected to the
connection port 131 of the patient mask 130. Activation of air flow
through the mask 130 is achieved by depressing the elastomeric
switch cap 1342 (Should this be 1340) which actuates the switch
1340 to occlude the pilot control circuit 360, which in the
embodiment illustrated in FIG. 18 includes the pilot control line
365 and the pilot control line extension tube 1330. The gas sparing
valve 330 is thereby opened. Although FIG. 18 illustrates using the
mask 130 in the system 1800, it is to be understood that the mask
130' may be also used.
[0167] FIG. 19 illustrates an exemplary alternative embodiment of
the hand piece of FIG. 13, generally designated as 1900 in FIG. 19,
in accordance with an exemplary embodiment of the present
invention. The hand piece 1900 includes all of the components of
the hand piece 1300, but the frame 1310 is modified as a frame
1310' having a smaller profile.
[0168] FIGS. 20A-20C illustrate various views of yet another
alternative embodiment of the hand piece of FIG. 13, generally
designated as 2000 in FIGS. 20A-C, in accordance with an exemplary
embodiment of the present invention. The hand piece 2000 includes
all of the components of the hand piece 1300, but the frame 1310 is
modified as a frame 1310'' having a smaller profile.
[0169] Referring now to FIGS. 22A through 22C, there are
illustrated, respectively, front, side, and perspective views of an
alternative embodiment of the patient mask 130', generally
designated in FIGS. 22A-22C as 130'', in accordance with an
exemplary embodiment of the present invention. The patient mask
130'' is similar to the patient mask 130', particularly in that it
includes the CPAP vent port 1700. The patient mask 130'' differs,
however, in that it further includes the pilot control switch 1340,
which is disposed on the patient mask 130'' in the embodiment
illustrated, rather than on a hand piece. FIGS. 23A through 23F
illustrate various views of various components of a combination of
the patient mask 130'' connected to the mask connection 1200, which
is connected to the disposable breathing circuit 120', in
accordance with an exemplary embodiment of the present
invention.
[0170] Referring now to FIG. 24, there is illustrated an exemplary
alternative embodiment of the gas sparing circuit 300, generally
designated in FIG. 24 as 2400, in accordance with an exemplary
embodiment of the present invention. In this gas sparing circuit
2400, the manual pneumatic pilot control line 365 of the breathing
circuit 120 or 120' is replaced by an electrical switch-activated
pilot control line 2465, and the mechanical pilot control switch
125 is replaced by an electric switch 2425, as shown in FIG. 24.
The electrical switch 2425 is placed under a pliant cap 1340 on the
mask 130''. The gas sparing circuit 2400 uses all the components
illustrated in FIG. 3, modified as described below, and additional
components as illustrated in FIG. 24. For example, the gas sparing
circuit 2400 incorporates the main gas branch 310 and the pilot
control branch 320, as modified to include an electrical pilot
control branch 2420 and an electrical pilot control line 2465. In
another exemplary embodiment, a CPAP branch, such as the CPAP
branch 430 of FIG. 4, could also be added to the gas sparing
circuit 2400 to add CPAP functionality.
[0171] The electrical pilot control branch 2420 of the gas sparing
circuit 2400 is an electronic control circuit which comprises an
electric solenoid valve 2410 configured to control the gas flow to
the main gas sparing valve 330. The electrically controlled
solenoid 2410 is a normally open valve that allows pilot gas to
vent to the atmosphere through a vent port 2414. The pilot input
320C is coupled to the valve 2410 at an inlet 2411. The outlet 2412
of the valve 2410 is coupled to the portion 320D of the pilot
control branch 320.
[0172] The valve 2410 operation is controlled electrically through
the pilot control circuit 360, specifically the electrical pilot
control branch 2420, the electrical pilot control line 2465, and
the switch 2425. The electrical pilot control branch 2420 comprises
wires 2422 and an optional timer circuit 2423, and the electrical
pilot control line 2465 is formed from wires. The optional timer
circuit 2423 functions to control the on time and off time of the
valve 2410 and, therefore, the on and off time of the gas sparing
valve 330, thereby providing for continued cycling of the gas
sparing valve 330 when activated. The pilot control line 2465
replaces the pilot control line 365 of FIG. 3. The pilot control
line 2465 couples to the connector 112 at a connection (input)
2416, thereby creating a complete electrical circuit with the
electrical pilot control branch 2420.
[0173] Operation of the gas sparing circuit 2400, with electronic
solenoid control, is now described. Operation begins with the
solenoid valve 2410 in the normally closed state which allows pilot
branch 1420 to be in the occluded state. In this condition the
pilot gas does not flow past the solenoid valve 2410 into the pilot
control line 320D. The gas sparing valve 330 remains closed as the
pilot line 320D on the gas sparing valve control side is vented to
atmosphere, P.sub.atm. Upon closure of electrical switch 2425, by
depression of the pliant switch cap 1340 on the mask 130'', an
electrical signal is sent through the wires 2465 and 2422, and the
solenoid valve 2410 is activated. Pilot gas flow is directed into
pilot line 320D. Pilot gas at pressure PB is applied to the control
side 333 of the gas sparing valve 330, and the valve 330 opens
allowing gas to flow into the main gas side 310, as described above
with respect to FIGS. 3, 6, and 7. The solenoid valve 2410 remains
activated, and main gas continues to flow until the switch 2425 is
released and the signal to the solenoid valve 2410 is deactivated.
Upon deactivation of the solenoid valve 2410, the pilot gas in the
circuit 2460 is occluded, and pilot gas in the line 320D is vented
to atmosphere through the vent port 2414. Pressure in the control
side 333 of the gas sparing valve 330 drops to P.sub.atm, and the
gas sparing valve 330 closes, thereby stopping main gas flow
through the circuit 310. This operation can is repeated manually
for each desired breath by depressing the pliant mask switch cap
1340.
[0174] In an alternative exemplary embodiment of the gas sparing
circuit 2400, there is an optional timer circuit 2423 that will
allow for cycling of the electrically controlled solenoid valve
2410 for the auto breath function with settable on and off times
for resuscitation. In this configuration and any of the timer
configurations described herein, the mask switch 2425 could have a
hold-closed latch to allow for the auto breath function to continue
after latching the switch closed so the user does not have to hold
the switch in place.
[0175] It is to be understood that the gas sparing circuit 2400 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply.
[0176] FIG. 25 illustrates a block diagram for yet another
exemplary embodiment of a gas sparing circuit, generally designated
as 2500, in accordance with an exemplary embodiment of the present
invention. The gas sparing valve 2530 in this embodiment is an
electrically activated solenoid valve 2530 which is controlled
through a mask switch, such as the mask switch 2425. In this
embodiment, in addition to the external gas inlet 111, there may be
an internal air generation-supply module 2510, which can create the
desired gas pressure and flow on demand to an outlet 2503. A
selector valve 2520 is used to select the appropriate gas source
from the inlet 111 or the internal air generation-supply module
2510.
[0177] Operation of the electrically controlled main gas solenoid
valve 2530 is controlled electrically through the electrical pilot
control circuit 2460. The solenoid valve 2530 is connected through
the wires 2422 of the electrical pilot control branch 2420 to an
external electrical pilot control line, e.g., the electrical pilot
control line 2465, and to a switch, e.g., the switch 2425. In an
exemplary alternative embodiment, the electrical pilot control
branch include the optional timer circuit 2423 that functions to
control the on time and off time of the valve 2530 and, therefore,
the on and off time of the main gas flow to the patient.
[0178] Operation of the gas circuit 2500, with electronic solenoid
control, is now described. Operation begins with the solenoid valve
2530 in the normally closed state which does not allow main gas
flow through the main gas circuit 350. Upon closure of the
electrical switch 2425 by depression of the pliant switch cap 1340
in the mask 130'', an electrical signal is sent through the wires
2465 and 2422, and the solenoid valve 2530 is activated. Main gas
flow is directed through the main gas branch 310. The solenoid
valve 2530 remains activated and main gas continues to flow until
the switch 2425 is released, at which time the signal to the
solenoid valve 2530 is deactivated. Upon deactivation of the
solenoid valve 2530, main gas flow stops. This operation can is
repeated manually for each desired breath by depressing the pliant
mask switch cap 1340.
[0179] In addition there is an optional timer circuit 2423 that
will allow for cycling of the electrically controlled solenoid
valve 2530 for the auto breath function with settable on and off
times for resuscitation. In this configuration and any of the timer
configurations described herein, the mask switch 2425 could have a
hold closed latch to allow for the auto breath function to continue
after latching the switch closed so the user does not have to hold
the switch in place.
[0180] It is to be understood that the gas sparing circuit 2500 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply 2510,
i.e., the internal supply 2510 is optional. Also, it is
contemplated that the gas sparing circuit 2500 can be applied
directly to either the internal gas supply 2510 or an external gas
supply via the inlet 111 to provide a time controlled breath pulse
through the outlet 2503 to the main gas side 310 and thus to the
patient through the port 117.
[0181] FIG. 26A illustrates and describes a block diagram for still
another exemplary embodiment of a gas sparing circuit, generally
designated as 2600, in accordance with an exemplary embodiment of
the present invention. This gas sparing circuit 2600 includes both
pneumatic manual pilot control functionality and automatic
electronic-based auto breath control that is activated by way of a
pneumatic valve/switch actuator 2603 disposed in the gas line
portion 320C. The pneumatic valve/switch actuator 2603 includes a
toggle 2603A for toggling between manual and automatic positions.
When the pneumatic valve/switch actuator 2603 is switched to the
automatic position, the gas sparing circuit 2600 cycles
electro-pneumatically in an automatic manner until the switch 2603
is set back to the manual position or gas pressure is removed from
the pilot line. This gas sparing circuit 2600 includes both the
manual pilot control functionality of FIG. 3 (the manual pneumatic
pilot control line 365 and the mechanical pilot air flow control
switch 125) and the electrical switch-activated pilot control of
FIG. 24 (the solenoid valve 2410 and electrical pilot control
branch 2420 with the electronic timer circuit 2423) for auto breath
capability. The solenoid valve 2410 is disposed in the portion 320D
connected to the control side 333 of the gas sparing valve 330.
[0182] Operation of the gas circuit 2600, with manual pilot control
and electrical switch-activated pilot control for auto breath
capability, is now described. Operation of the gas sparing circuit
2600 is identical in operation to FIG. 3 when the pneumatic
valve/switch actuator 2603 is in the manual gas control position
for utilization of the pilot control circuit 320, specifically the
pilot control line 365 and flow control switch 125. In this
configuration the electronically controlled solenoid valve 2410 is
in a normally open configuration when no control signal is provided
and pilot gas can pass through the solenoid valve 2410 freely.
[0183] When the pneumatic valve/switch actuator 2603A is set in the
manual position, pilot gas flows through the pilot control line
320C. When the pilot control line 365 is occluded by use of the
flow control switch 125, the pilot circuit 320C becomes occluded,
thereby allowing pilot gas to flow through the solenoid valve 2410
and the control line 320D. Pilot gas at pressure PB is applied to
the control side 333 of the gas sparing valve 330, and the valve
330 opens, thereby allowing gas to flow into the main gas branch
310, as described above with respect to FIGS. 3, 6, and 7.
Releasing the mask switch 125 causes the pressure to drop in the
pilot line 320D and at control side 333 of the gas sparing valve
330, and the valve 330 closes, thereby stopping gas flow into the
main gas branch 310, as described above with respect to FIGS. 3, 6,
and 7.
[0184] When the pneumatic valve/switch actuator 2603 is set in the
auto breath position, a toggle 2613A electrically connected to the
electronic timer circuit 2423 is closed, and the electronic time
circuit 2423 is energized. Additionally, gas is directed to the
pilot line 320D and the control side 333 of the gas sparing valve
330, which opens to allow gas flow through the main gas side 310.
At this time, the electronic timer circuit 2423 begins to cycle the
electronic solenoid valve 2410 between the normally open position,
which allows pilot gas flow through its outlet 2412 to the gas
sparing valve 330, and the closed position, in which the solenoid
2410 stops pilot flow to the outlet 2412 and to the gas sparing
valve 300 at the control side 333. In the closed position of the
electronic solenoid 2410, flow is closed at inlet 2411, but flow is
then opened at the vent 2414, which allows the pilot control line
320D to vent and the pressure at the control side 333 to drop to
P.sub.atm, thereby closing the gas sparing valve 330 and stopping
flow in the main gas side 310. The electronic timer 2423 cycles the
solenoid valve 2410 between the closed and open state creating a
controlled auto breath function that can be user adjusted for on
time and off time. This operation continues until the valve/switch
actuator 2603 is set back to the manual position by way of the
toggle 2603A.
[0185] It is to be understood that the gas sparing circuit 2400 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply, as
shown in FIG. 25.
[0186] Now turning to FIG. 26B, there is illustrated a block
diagram for yet another exemplary embodiment of a gas sparing
circuit 2600', in accordance with an exemplary embodiment of the
present invention. This gas sparing circuit 2600' includes both the
manual pilot control functionality of FIGS. 3 and 4 (the gas
sparing circuit 400) and the electrical switch-activated pilot
control of FIG. 24 (the electrically controlled solenoid pilot
valve 2410) for auto breath capability with the exception that the
electrical switch-activated pilot control valve 2410 is located in
a removable accessory enclosure 2650 external to the gas sparing
circuit 400 and is attached to the pilot control port 116 at outlet
112. An electrical switch 2655 in the accessory enclosure 2650
activates the electronic pilot circuit control.
[0187] The gas sparing circuit 2600' incorporates a gas sparing
configuration identical to the gas sparing circuit 400 shown in
FIG. 4 and includes the resuscitation side 410 and the CPAP side
420. In addition to including the gas sparing circuit 400, the gas
sparing circuit 2600' further includes the removable auto breath
control module 2650 connected to the outlet port 116 of the gas
sparing circuit 400. The removable auto breath control module 2650
includes its own pilot control port 116'. When not installed, the
breathing circuit 120 or 120' can be attached to the gas port 112
(described above with respect to FIG. 4). When the auto breath
control module 2650 is attached to the pilot control port 116, the
pilot control line 365 of the breathing circuit 120 or 120' can
still be connected to the pilot control port 116' for manual
operation.
[0188] The auto breath control module 2650 includes an inlet line
2651, which connects to the pilot control port 116, and an outlet
line 2652, which connects to a pilot outlet port 116'. An
electronic solenoid valve 2410 is connected between the inlet and
outlet lines 2651 and 2652. Specifically, an inlet 2411 of the
electronic solenoid valve 2410 is connected to the inlet port 2651,
and an outlet 2412 of the electronic solenoid valve 2410 is
connected to the outlet port 2652. A timer circuit 2433 is
connected to the electronic solenoid valve 2410 through wires 2424
and to a control switch 2655 via wires 2654. The pilot control line
365 of circuit 120 connects to outlet port 116' of the auto breath
control module and provides for manual control.
[0189] Operation of the gas circuit 2600' of FIG. 26B, with manual
pilot control and electrical switch-activated pilot control for
auto breath capability, is now described. The external auto breath
module 2650 is attached to the gas control circuit 410 through the
inlet line 2651 of the auto breath control module 2650 which is
connected to the pilot port 116 of the main gas circuit 410. The
output line 2652 is provided from the auto breath control module
2650 for connection to the pilot control line 365 of breathing
circuit 120. For operation of gas circuit 2600', the main gas line
355 of breathing circuit 120 is connected to outlet port 117, as
described with respect to FIGS. 3 and 4. The pilot control line 365
of breathing circuit 120 is connected to the outlet port 116' of
the auto breath control module 2650.
[0190] When the auto breath control module control switch 2655 is
in the Off position the electronic solenoid valve 2410 is in the
normally open position allowing pilot gas to flow unrestricted
through the solenoid valve 2410. Then operation of the gas sparing
circuit 2600' is identical in operation to that described in FIGS.
3 and 4 with manual control of the main gas line 320 provided
through activation of the pilot control switch 125.
[0191] If auto breath functionality is desired, the control switch
2655 on the auto breath control module 2650 is switched to the On
position. The timer circuit 2423 is energized and then cycles the
solenoid valve 2410 from the normally open position to the normally
closed position. The pilot line 320C is then occluded at solenoid
input 2651 and pilot gas flow is directed into the pilot control
line 320D. Pilot gas at pressure P.sub.B is applied to the control
side 333 of the gas sparing valve 330, and the valve 330 opens
allowing gas to flow into the main gas side 310, as described above
with respect to FIGS. 3, 6, and 7. The solenoid valve 2410 remains
activated, and main gas continues to flow until the timer 2423
cycles the solenoid valve 2410 to the normally open position, at
which time the solenoid valve 2410 vents the pilot line 320C
through the solenoid valve to the pilot control line 365 and out
vent port 351 on the mask switch 125. At this time pressure in the
control side 333 of the gas sparing valve 330 drops to P.sub.atm,
and the gas sparing valve 330 closes, thereby stopping main gas
flow through the circuit 310. The electronic timer 2423 cycles the
solenoid valve 2410 between the closed and open state to create a
controlled auto breath function that can be user adjusted for on
time and off time. This operation continues until the control
switch 2655 is set back to the Off position.
[0192] It is to be understood that an alternate embodiment for the
external electronic auto breath control module 2650 would be to
utilize pneumatic timers such as those illustrated in FIG. 10, FIG.
27, and FIGS. 28 and 29, and a pneumatic valve/switch as necessary
but in a configuration where the pneumatic timers would be located
within an external removable module, as described in FIG. 26B. In
another exemplary embodiment, CPAP branch portion 430B could be
connected to main branch portion 310B allowing the pressure relief
valve 118 to be disposed downstream of the connection with the
portion 430B. In such embodiment, the pressure relief valve 118
provides venting for overpressure in either the CPAP branch 430 or
the primary branch 310. Furthermore, it is to be understood that
the gas sparing circuit 2400' may be modified to include an
internal gas supply.
[0193] FIG. 27 illustrates still another exemplary embodiment of a
gas sparing circuit, generally designated as 2700, in accordance
with an exemplary embodiment of the present invention. This gas
sparing circuit 2700 includes both pneumatic manual pilot control
functionality through the attached circuit and automatic pneumatic
timer based auto breath control set with a switch on the gas
control unit instead of having to hold the manual pilot line
occluded. Once switched to automatic, the gas sparing circuit 2700
cycles pneumatically until the switch is set back to manual or gas
pressure removed from the pilot line. This gas sparing circuit 2700
includes both the manual pilot control functionality of FIG. 3 (the
manual pneumatic pilot control line 365 and the pilot air flow
control switch 125) and the pneumatic timer pilot control of FIG.
10 for auto breath capability.
[0194] Operation of the gas sparing circuit 2700, with manual pilot
control and pneumatic timer activated pilot control for auto breath
capability, is now described. Operation of the gas sparing circuit
2700 is identical in operation to the gas sparing circuit 300 in
FIG. 3 when the pneumatic valve/switch actuator 2702 is in the
manual control position for utilization of the pilot circuit
portion 320C in conjunction with pilot control line 365 and flow
control switch 125. In this configuration, when the pneumatic
valve/switch actuator 2702 is set in the manual position the
pneumatic timers 1010 and 1020 are not active and pilot flow
bypasses the timers and is directed to pilot control line 320C.
When the pilot control line 365 is occluded by use of flow control
switch 125, pilot circuit 320C is also occluded allowing pilot gas
to flow through line 2701B and into pilot line 320D. Pilot gas at
pressure PB is applied to the control side 333 of the gas sparing
valve 330 and the valve opens allowing gas to flow into the main
gas side 310 as described above with respect to FIGS. 3, 6, and 7.
Releasing mask switch 125 causes the pressure to drop in pilot line
320D and at control side 333 of the gas sparing valve and the valve
closes stopping gas flow into the main gas side 310 as described
above with respect to FIGS. 3, 6, and 7. When the pneumatic
valve/switch actuator 2702 is set in the auto breath position, the
pneumatic timer circuit is activated and auto breath operation
occurs in an automatic manner. When the pneumatic valve/switch
actuator 2702 is set in the auto breath position pilot gas is
directed to the pneumatic timer through line 1030A and operation
occurs in the same manner as described with respect to gas sparing
circuit 1000 in FIG. 10. At this time the pneumatic timers 1010 and
1020 begin to cycle the pilot gas flow on and off based on used
selected time settings, to the gas sparing valve 330. In the first
part of the timer cycle pilot gas is directed from the timer
circuit through line 1030E to pilot line 320D and at control side
333 of the gas sparing valve 330 and the valve opens to allow gas
flow through main gas side 310. In the second part of the timer
cycle pilot gas flow is stopped to the gas sparing valve 300 at
control side 333 which allows the pilot control line 320D to vent
and the pressure at control side 333 to drop to Patm, closing the
gas sparing valve 330 and stopping flow in the main gas side 310.
The pneumatic timers 1010 and 1020 cycles the gas sparing valve 330
between the closed and open state creating a controlled auto breath
function that can be user adjusted for on time and off time. This
operation continues until the pneumatic valve/switch actuator 2702
is set back to the manual position or gas pressure is removed from
the pilot line.
[0195] It is to be understood that the gas sparing circuit 2700 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply.
[0196] FIG. 28 illustrates a block diagram for a further exemplary
embodiment of a gas sparing circuit 2800, in accordance with an
exemplary embodiment of the present invention. This gas sparing
circuit is similar to the gas sparing circuit 1000 illustrated in
FIG. 10. As described herein, the gas sparing circuit 1000 uses an
on-timer 1020 and an off-timer 1030 to control the auto breath
circuit 1000. The gas sparing circuit in FIG. 28 uses two on-timers
2820, 2830, and a 4-way spool valve 2810 to effectively make one
on-timer (the on-timer 2830) and an off-timer (the other on-timer
2820), without having to use a real off-timer, to control the
pneumatically timing circuit 2800. The result is a gas sparing
circuit that has the same control of inhalation and exhalation
breath as the circuit 1000. In this gas sparing circuit 2800, as in
the gas sparing circuit 1000, auto breath operation is activated
through occlusion of the pilot line 365 at switch 125. Auto breath
function stops when the pilot line 365 is un-occluded at mask
switch 125.
[0197] It is to be understood that the gas sparing circuit 2800 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply.
[0198] FIG. 29 illustrates and describes a block diagram for
another exemplary embodiment of a gas sparing circuit 2900, in
accordance with an exemplary embodiment of the present invention.
This gas sparing circuit is similar to the gas sparing circuit 2700
in FIG. 27 but uses two on-timers 2820 and 2830 and a 4-way spool
valve 2810 to effectively make one on-timer (the on-timer 2830) and
one off-time (the off-timer 2620), without having to have a real
off-timer, to control the pneumatically timing circuit 2900. As
with gas sparing circuit 2700 in FIG. 27, the function of the gas
sparing circuit is activated by pneumatic valve/switch 2702 so that
manual pilot control is still possible with this gas sparing
circuit but the circuit can be switched into automatic auto breath
mode without having to hold the external pilot line 365
occluded.
[0199] It is to be understood that the gas sparing circuit 2700 may
be modified as described herein to provide for CPAP functionality
as shown in FIG. 4 and/or to include an internal gas supply.
[0200] An exemplary feature which may be added to any of the
exemplary embodiments of the gas sparing circuits described herein.
In any of the gas sparing circuits having manual pilot control
lines 365, a latch can be added to the switch 125 or 1340 or 2425
to allow the switch to be held closed without the need for the user
to apply constant pressure to the switch 125 or 1340 or 2425. This
latch may be desirably used for auto breath modes to allow the user
to not have to hold the switch 125 or 1340 or 2425 down
continuously.
[0201] Now referring to FIG. 30, there is illustrated an exemplary
embodiment of a gas sparing circuit 3000 which functions similarly
to the gas sparing circuit 300 of FIG. 3, but further includes a
pressure surge damper configuration, in accordance with an
exemplary embodiment of the present invention. The pressure surge
damper configuration comprises a series of damping elements
comprising reducing elements 3020, reduced tube ID sections 3040,
and expansion elements 3030 in exemplary positions to dampen gas
pressure surges that may occur in the main gas line 310B when the
gas sparing valve 330 opens. It is to be understood that this
pressure surge damper configuration may be added to any of the
exemplary gas sparing circuits described herein.
[0202] Operation of the pressure surge damper configuration using
reducing elements 3020, reduced ID elements 3040, and expansion
elements 3030 is now described. Referring to FIG. 30, as the gas
sparing valve 330 opens pressurized gas quickly flows into the main
gas line 310B. This instant release of pressurized gas flow can
create a pressure wave front in the main gas line 310C, 310D and
310E that may be slightly higher than the steady state pressure
after the gas sparing valve 330 has been opened for a period of
time. It may therefore be beneficial to dampen this pressure surge
using a pressure surge damper system containing damping elements
3020, 3030 and 3040 as illustrated. As the gas pressure front moves
along main gas line 310B it encounters the reducer element 3020 in
the main gas line. The gas pressure enters the reducer 3020 where
the flow path ID is decreased abruptly creating a velocity increase
in the gas flow and a turbulence effect. The gas flow then
traverses through a reduced ID flow element 3040 and then enters an
expansion element 3030 where the flow path ID is increased abruptly
creating a velocity decrease and a second turbulent effect which
combines to reduce the pressure wave an incremental amount.
Additional elements located at 3020', 3030' and 3040' and at
3020'', 3030'' and 3040'' are added to further dampen the pressure
surge to the desired level. By combining a series of these elements
in series, or if desired in parallel, the pressure wave front can
be either partially suppressed or fully suppressed as desired. As
the initial pressure surge damper elements 3020, 3030, and 3040 act
to dampen the pressure wave front, the main gas with a reduced
pressure wave progresses through main gas line 310C' to line 310D
and then to damping elements 3020', 3030' and 3040' where the
pressure wave front is reduced further. The main gas then
progresses through main line 310D' with even further reduction in
the amplitude of the pressure wave front to main line 310E. The gas
then interacts with the damping element 3020'', 3030'' and 3040''
where again the pressure wave front is further reduced to the point
where it is totally eliminated and the main gas, without the
pressure wave front, then progresses to the reaming main gas lines
310E' and into the breathing circuit 120 at outlet 117. When the
gas sparing valve 330 is closed, and the gas flow in the main gas
line 310B ceases. The pressure surge damper configuration is then
ready for the next pressure wave.
[0203] In an exemplary alternative embodiment, a pressure surge
damper 3010 may be used in place of or in addition to the dampening
elements illustrated in FIG. 30 and described above. FIG. 30A
illustrates an exemplary embodiment of the damper 3010, in
accordance with an exemplary embodiment of the present invention.
The pressure surge damper contains a base 3027, with inlet port
3021, a pliant damper diaphragm 3023, a spring 3024, a vent control
valve 3025 with vent port 3026, and a cap 3028. The diaphragm 3023,
cap 3028, and base 3027 interact to create a sealed damper chamber
3022. This pressure damper is shown in the unpressurized state.
[0204] Operation of the pressure surge damper 3010 is now
described. Referring to FIGS. 30 and 30A, as the gas sparing valve
330 opens pressurized gas quickly flows into main gas line 310B.
This instant release of pressurized gas flow can create a pressure
wave front in the main gas line 310C, 310D and 310E that may be
slightly higher than the steady state pressure after the gas
sparing valve has been opened for a period of time. It may
therefore be beneficial to dampen this pressure surge using a
pressure surge damper 3010 as illustrated. As the gas pressure
front moves along main gas line 310B it encounters the pressure
surge damper 3010 at a 90 degree bend in the main gas line. The gas
pressure enters the inlet port 3021 of the pressure surge damper
and encounters the pliant damper diaphragm 3023. The gas pressure
fills the sealed damper chamber 3022 and forces the damper
diaphragm to expand and move against the spring 3024. The air
trapped behind the pliant diaphragm is compressed and in a
controlled manner exits through the vent port 3026. The vent
control valve 3025 controls the rate at which the air can be vented
from the space behind the pliant diaphragm and thus the rate at
which the pliant diaphragm can expand and move against the spring.
The pliant diaphragm 3023 in combination with the spring 3024 and
the vent control valve 3025 act together to create a controlled
damping effect on the main gas entering the inlet port. As the
pressure surge damper 3010 acts to dampen the pressure wave, the
pliant diaphragm 3023 reaches its full equilibrium travel and the
main gas without the pressure wave then progresses to the reaming
main gas lines 310C, 310D, 310E and into the breathing circuit 120.
When the gas sparing valve 330 is closed, and the gas flow in the
main gas line 310B ceases, the pliant diaphragm 3023 returns to its
original unpressurized condition by reaction force of the spring
3024. The pressure surge damper is then ready for the next pressure
wave.
[0205] FIGS. 31A and 31B illustrate the damping effect of the
pressure surge damper 3010 in the gas sparing circuit 3000. FIG.
31A illustrates the pressure in the main gas line after the time
T.sub.1 that the gas sparing valve 330 opens without the pressure
surge damper. The pressure in the main gas line 310 increase
quickly to P.sub.2 which is the surge pressure and is above the
steady state pressure P.sub.1. The pressure then drops at time
T.sub.2 to the steady state pressure P.sub.1. FIG. 31B illustrates
the pressure in the main gas line after the time T.sub.1 that the
gas sparing valve 330 opens with the pressure surge damper. The
pressure in the main gas line 310 is damped and slowly increases to
P.sub.1, the steady state pressure at time T.sub.2. The pressure
wave in the main gas line 310 is suppressed and no pressure spike
occurs at the breathing circuit 120.
[0206] FIG. 32 illustrates an exemplary alternative embodiment of
the endotracheal (ET) hand piece 1500 of FIG. 15, generally
designated as 1500' in FIG. 32, in accordance with an exemplary
embodiment of the present invention. The ET hand piece 1500'
includes several similarities with the ET hand piece 1500. For
example, the inlet port 1530 of the ET hand piece 1500' is
configured to be connected to the rotating outlet port 1220 of the
mask connection 1200, and the outlet port 1550 of the ET hand piece
1500' is configured to be connected to the endotracheal tube 1560.
Furthermore, the ET hand piece 1500' includes the pilot control
switch 1340', as does the ET hand piece 1500, but further includes
a CPAP vent port 1700' containing the CPAP valve 1706' and port cap
1704' as described in FIGS. 22 and 23, which the ET hand piece 1500
does not contain. When used in conjunction with the gas sparing
circuit 400 of FIG. 4 set to CPAP mode, the port cap 1704' is
removed from the valve housing 1702' and CPAP functionality is
possible.
[0207] It is to be understood that the ET hand piece 1500' may be
modified as described herein to include electrical wires such as
those illustrated in FIG. 24, element 2465, and an electrical
switch similar to switch 2425 in FIG. 24 to allow functionality
with the gas sparing circuit 2400 shown in FIG. 24.
[0208] Because the various embodiments of the gas sparing systems,
devices, and circuits described herein provide for control of main
(primary) gas, large continuous gas flows are minimized, and gas is
conserved. In addition, the gas sparing systems, devices, and
circuits described herein allow for precise pressure and volume
control. Several examples of patient interfaces, such as the masks
130, 130', 130'', and 130''' and ET hand pieces 1500 and 1500', are
described herein for delivering the gas to a patient. It is to be
understood that the patient interfaces are not limited to these
examples.
[0209] These and other advantages of the present invention will be
apparent to those skilled in the art from the foregoing
specification. For example, it is contemplated that the gas sparing
valve 330 and the pilot control line 365 may be replaced,
respectively, by an electronically controlled valve and a switch
coupled to the valve via a conductor for selective control of the
valve. Further, the pneumatic timer controls may be replaced by
electrical timer controls. Accordingly, it is to be recognized by
those skilled in the art that changes or modifications may be made
to the above-described embodiments without departing from the broad
inventive concepts of the invention. It is to be understood that
this invention is not limited to the particular embodiments
described herein, but is intended to include all changes and
modifications that are within the scope and spirit of the
invention.
* * * * *