U.S. patent number 3,882,847 [Application Number 05/423,762] was granted by the patent office on 1975-05-13 for low-cost pneumatic apnea or respiration monitor.
Invention is credited to Harvey Barry Jacobs.
United States Patent |
3,882,847 |
Jacobs |
May 13, 1975 |
Low-Cost Pneumatic Apnea or Respiration Monitor
Abstract
Low-cost pneumatic apnea or respiration monitor adapted to sound
an alarm for a patient whose breathing is controlled by a
ventilator or whose respiration has ceased. In the disclosed
arrangement, pressure from an air pressure source is modulated by
chest movement to admit air to either of two air storage tanks,
each of these storage tanks having an adjustable throttle or bleed
valve in a vent. Each tank feeds air to a low pressure actuated
switch or valve which actuates an alarm when the pressure falls
below a critical low value in the storage tanks indicating a
slowing or cessation of breathing.
Inventors: |
Jacobs; Harvey Barry (Reston,
VA) |
Family
ID: |
23680080 |
Appl.
No.: |
05/423,762 |
Filed: |
December 11, 1973 |
Current U.S.
Class: |
600/534;
340/573.1; 340/626 |
Current CPC
Class: |
A61M
16/0051 (20130101); A61B 5/1135 (20130101) |
Current International
Class: |
A61B
5/11 (20060101); A61B 5/113 (20060101); A61M
16/00 (20060101); A61b 005/10 (); A61m
016/00 () |
Field of
Search: |
;128/25,DIG.29,203,2R,142,147.2,145.8,145.6 ;340/279 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
IBM Technical Disclosure, Vol. 6, No. 6, 11/63..
|
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Dunne; G. F.
Attorney, Agent or Firm: Saffitz; Abraham A.
Claims
What is claimed is:
1. A pressure fluid breathing monitor for a patient comprising:
a support,
a valve means having two relatively movable valve parts;
a body belt adapted to partly surround the patient's chest;
means connecting one end of the belt to one valve part and means
for connecting the other end of the belt to said support;
said valve parts moving relatively to each other in response to the
inhalation and exhalation motions of the chest;
a source of pressure fluid connected to the valve means;
pressure fluid operated alarm means including two alarm devices,
each connected to said valve means by a separate conduit means, one
alarm responding to abnormal inhalation motion and the other to
abnormal exhalation motion;
conduit means connecting said alarm means to said valve means to
receive pressure fluid therefrom for operation of said alarm
device;
delay means connected to said conduit means to control the time
interval wherein the pressure fluid effects the activation of the
alarm means; and,
said relatively movable valve parts controlling the flow from said
pressure fluid source to said conduit means in response to the
inhalation and exhalation motions of the chest.
2. The breathing monitor as claimed in claim 1 wherein one valve
part is mounted on a support resting on the chest with one belt end
connected to the support and the other belt end connected to the
other valve part.
3. The breathing monitor as claimed in claim 2 wherein the movable
valve parts comprise two nested outer and inner parts, with the
source of pressure fluid and the conduit means connected to the
other valve part.
4. The breathing monitor as claimed in claim 3 wherein the outer
part comprises a tubular member secured to said support and having
three spaced ports, one connected to the source of pressure fluid
and the others to the conduit means, and wherein the inner part
carries means to interconnect the pressure fluid source to either
of said ports.
5. The breathing monitor as claimed in claim 4 wherein spring means
are provided to act on the inner part to bias it to a desired
position to interconnect the pressure fluid source to a port.
6. The breathing monitor as claimed in claim 4 wherein the delay
means comprises a vent to permit a portion of the pressure fluid
flowing to the alarm device to escape.
7. The breathing monitor as claimed in claim 6 wherein an
adjustable throttle valve controls the flow through the vent.
8. The breathing monitor as claimed in claim 4 wherein the delay
means comprised a fixed volume tank with a throttle valve
controlling the flow and quantity of fluid within the tank.
9. The breathing monitor as claimed in claim 5 wherein the delay
means comprises a fixed volume tank connected to the conduit means,
a vent connected to the tank, an adjustable throttlevalve to
control the flow through the vent and a conduit connecting said
tank to said alarm device.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a low-cost apnea or respiration monitor
which is adapted to sound an alarm for a patient whose breathing is
controlled by a ventilator or which signals the stopping of
breathing in a patient not on a respirator whose illness requires
monitoring.
More particularly, the invention relates to a low-cost, reliable,
respiration monitor which operates on simple mechanical and
pneumatic principles and is not subject to electrical failure as
may be caused by deterioration of electronic components such as
capacitors, vacuum tubes, or transistors.
In the pneumatic system described herein, pressure from an air
pressure source is modulated by chest movement to admit air to
either or two air storage tanks, each of these storage tanks having
an adjustable bleed valve. Each tank feeds air to a low pressure
switch or valve which actuates an alarm when the pressure falls
below a critical low value in the storage tanks indicating a
slowing or cessation of breathing.
OBJECTS OF THE INVENTION
An object of the invention is to provide a low-cost apnea or
respiration monitor which is free from capacitors, vacuum tubes and
other electronic components and which operates on pressure fluid
principles. The pressure system is provided with time delay means
to indicate by audible, visual, and other alarm means failure of
breathing of the patient in either the inspriatory or expiratory
phase of each respiration cycle to indicate cessation of breathing
by the patient.
BRIEF DESCRIPTION OF THE DRAWING
Other objects of the invention will become apparent from the
following detailed description and drawings, in which:
FIG. 1 is a partially diagrammatic illustration showing the chest
air valve unit connected to the appropriate pneumatic pressure
sources and delay air storage tanks for inhalation and exhalation,
respectively.
FIG. 2 is detail partly in section and partly in elevation of one
end of the chest air valve unit showing the spring meter mechanism
for the air valve piston.
FIG. 3 is a sectional view showing one of the stops at each end of
the chest air valve unit which limits the reciprocating movement of
air valve piston in response to inspiration and exhalation.
FIG. 4 is an elevational view of the rigid chest mounting plate
which can be detached from the air valve unit when the latter is
repaired or replaced.
FIG. 5 is a sectional diagrammatic view of the chest air valve unit
in mid respiration.
FIG. 6 is a sectional diagrammatic view of the chest air valve unit
in exhalation phase.
FIG. 7 is a sectional diagrammatic view of the chest air valve unit
in inhalation phase.
The several figures herein illustrate a pressure system for an
apnea monitor in which thoracic movement actuates alarms or
signals. The basic principle of the pressure chest monitor system
is that increments of air supplied to an air tight tank will
gradually build up the pressure in that tank to the level of the
source of air pressure. If the tank has a continuous slow vent or
leak the maximum pressure that can be built up by a regular series
of inputs will be lower because of leakage. A calibrated pressure
switch or valve connected to the air tank will be actuated if the
incoming increments of air continue for a time period set by the
adjustable throttle valve for respiration rate. The actuation of
the switch due to this change in input to the tank can be utilized
to energize an alarm indicating that the input has decreased or
stopped entirely. A pressure gauge connected to the tank measures
the respiration rate on the lowest swing of the guage's needle. The
slower the respiration rate the higher the pressure is in the tank
per impulse and the faster the respiration, the lower pressure per
impulse. Thus, the tank acts as an adjustable timing means for
varying or delaying the timing of pressure built up in the system
and activating the alarm means.
FIG. 1 is a schematic view of an air valve 61 receiving air under
pressure from source 91 through input 74 to a tubular member 66.
Preferably this tube should be transparent and the impact-resistant
synthetic resin known as ABS, available from the Carlon Company,
has been found satisfactory. Tubular member 66 has two other ports
75 and 76 extending respectively to air tanks 96 and 92. Each of
the air tanks has an adjustable throttle valve 97 and 93
respectively, and a low pressure switch 98 and 94 respectively.
Tube 66 is supported on a breastplate 63 by means of footing
members 85 and 86, each of which holds a circular supporting unit
83 and 84. The tube 66 is snugly retained near each end by these
ring-shaped members 83 and 84. Within the tube member 66 is a
reciprocating unit comprising a rod 70 having an eye-shaped member
72 at one end. This member 70 is threaded to receive threaded
members 68 and 69. Secured to threaded members 68 and 69 are
tubular members 67 and 100. The opposite ends of the tubular
members 67 and 100 carrry piston unitis 64 and 65. These piston
units 64 and 65 are slidable within the tube 66. As shown in FIGS.
5, 6 and 7 they shift from the mid position of FIG. 6 to the left
and right in accordance with the motion of rod 70.
Rod 70 may be connected at eye 72 to a snap fastener 73 that is
secured to a body belt member 79 that surrounds the body of the
patient. The opposite end of belt 79 as shown at the right side of
FIG. 1 has a detachable hook 80 that may be secured in a
corresponding opening 81 that is part of the chestplate 63.
As portrayed in FIG. 7, when the patient takes a breath, the belt
79 pulls on eye 72 drawing the rod 70 to the left. The two plungers
64 and 65 will then be positioned so the air in the pressure tank
can enter tube 66 at port 74 and escape at port 76. This adds an
increment of air to tank 92.
Conversely, as shown in FIG. 6, when the patient breathes out belt
70 becomes slack, allowing rod 70 to move to the left under the
influence of two springs to be described presently. At this moment
of exhalation, as shown in FIG. 6, the pistons 64 and 65 permit air
from the pressure tank to enter at port 74 and to leave port 75 to
go to tank 96.
Thus, tank 92 can be designated the inhalation tank and the tank 96
can be designated the exhalation tank. Since both tanks are
equipped with adjustable throttle valves 93 and 97, any slowness of
operation of rod 70, or cessation of motion thereof, will soon
result in a rise of pressure in one or the other of the two tanks.
Such rise in pressure will actuate the appropriate signal alarm 95
or 99 to notify an attendant of the critical situation respecting
this particular patient.
Pressure gauges 106 and 107 may be attached to timing tanks 92 and
96. To an observer, the pressure gauges will indicate the breathing
conditions of the patient by registering the low and high pressure
cycles in the attached tank. Too high pressure would indicate that
the patient's chest is not moving sufficiently for proper
breathing.
The spring suspension that causes rod 70 to return to the extreme
right position when not under any pull from the belt 79 is shown in
detail in FIG. 2. This figure shows the left half of the rod 10
portrayed in FIG. 1. The piston member 65 is a snug fit within the
plastic tube 66 and carries a tubular member 67 which is secured to
the threaded member 69 at its other end. Consequently, the weight
of one end of rod 70 is carried through the agency of member 69,
tube 67 and piston 65 by the tube 66.
Exactly similar support means is found at the right end of tube 66
and rod 70 where piston 64 carries the tubular member 100 threaded
member 68 and the right end of threaded rod 70.
It will be seen that the threaded members 68 and 69 can position
the pistons 64 and 65 in different lengthwise locations along rod
70 and thereby determine the interval between the passage of these
pistons over the ports 75 and 76.
Referring again to FIG. 2, the tube member 67 is surrounded by coil
spring 89. This coil spring is secured, as by soldering, to the
tube 67 at point 101. The other end of the spring is secured, as by
crimping, over the edge of tube 66. The spring 89 is under partial
compression when the rod 70 is in mid position shown in FIG. 5. At
this moment the other spring 88 at the right end is under partial
tension. Consequently, rod 70 is released from any pull by the belt
79 will spring to the right end under the impetus of two springs.
This is the situation in FIG. 6.
It is desirable that pistons 64 and 65 be limited in their extreme
movements to avoid pulling them from tube 66. FIG. 3 shows such a
stop member comprising a rubber grommett which fits snugly over the
end of tube 66 and projects inwardly into the tube to the point
where the motion of the piston is to be stopped. This grommett is
indicated as 77 and 78 in FIG. 1.
FIG. 4 is a partial detail of the supporting means and the tube 66
carried by the supporting means. This figure might be regarded as
the stationary portion of the air valve, the other elements moving
more or less in accordance with the pull on belt 79 produced by the
action of the patient's chest in breathing. Footing members 85 and
86 are shown attached to the breastplate 63. The latter is shown as
slightly curved at each end to conform to the human anatomy. At the
top of parts 85 and 86, ring-shaped members 83 and 84 are secured
and in turn carry the transparent tube 66 approximately at each end
thereof. At the right end of breastplate 63 an apertured projection
81 provides means for detachably connecting the body belt 79 to the
breastplate.
From the above description of a preferred embodiment of my
pneumatic respiration monitor, it will be seen that no electricity
is employed in the vicinity of the patient and need not be employed
in the same room as the patient. If the alarms 95 and 99 are
electrical, they can be energized by pneumatic tubing from an
adjoining room. In some situations (operating rooms, for example),
electrical sparks are to be avoided at all costs. The alarms may be
pneumatic, such as an air whistle.
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