U.S. patent number 3,785,377 [Application Number 05/197,001] was granted by the patent office on 1974-01-15 for plant, preferably for anaesthesia.
Invention is credited to Soren Jorgensen.
United States Patent |
3,785,377 |
Jorgensen |
January 15, 1974 |
PLANT, PREFERABLY FOR ANAESTHESIA
Abstract
Anaesthetic gas is maintained in a closed system and exhausted
in an area external to the area wherein the anaesthetic equipment
is operated according to the disclosed apparatus. The apparatus for
administration of anaesthesia includes a controlled source of
anaesthetic gas, a mask, check valves on either side of the mask,
carbon dioxide absorber, rubber bag, and means for removal of
circulated anaesthetic gas from the system. Inlet and outlet from
the system may be conveniently controlled thereby maintaining
substantially the same pressure throughout the system. The
apparatus disclosed provides that harmful anaesthetic gases
exhausted from the system do not reach the ambient air surrounding
the apparatus, thus the staff working in the area of the apparatus
is protected from exposure to the gases.
Inventors: |
Jorgensen; Soren (Odense,
DK) |
Family
ID: |
26067704 |
Appl.
No.: |
05/197,001 |
Filed: |
November 9, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Nov 12, 1970 [DK] |
|
|
5753/70 |
Oct 15, 1971 [DK] |
|
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5038/71 |
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Current U.S.
Class: |
128/205.12;
128/910; 128/205.23 |
Current CPC
Class: |
A61M
16/0833 (20140204); A61M 16/009 (20130101); A61M
16/22 (20130101); A61M 16/0808 (20130101); Y10S
128/91 (20130101); A61M 2016/003 (20130101) |
Current International
Class: |
A61M
16/00 (20060101); A61M 16/22 (20060101); A61m
017/00 () |
Field of
Search: |
;128/188,142.2,142.4,145.8,146,146.3,146.4,142,142.3,145,146.5
;417/151,158 ;73/200,209 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Recla; Henry J.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
I claim:
1. Apparatus for the administration of anaesthetics comprising a
closed system including a mask, inlet means, carbon dioxide
absorption means, rubber bag, at least one check valve, inlet
means, a branched pipe, a flowmeter, a regulating valve and a
vacuum means,
said inlet means provided for the introduction of anaesthetic gas
from a rotameter metering means into said system and communicated
to said carbon dioxide absorption means;
said carbon dioxide absorption means for the absorption of carbon
dioxide of the expiratory air and communicated to said branched
pipe;
said branched pipe communicated to said rubber bag and said vacuum
means for controlled suction and substantially continuous,
uninterrupted exhaust of at least a portion of said anaesthetic gas
from said system;
said vacuum means comprising a T-shaped ejector suction unit
including an inlet and outlet means, a source of pressurized gas
and an exhaust means communicated to said branched pipe of said
system, said inlet and outlet means disposed from each other and
containing therebetween a first and second truncated cone jet
bodies spaced apart from each other, their narrow ends facing each
other, said first cone contained in said inlet means and positioned
such that the narrow end thereof extends over said exhaust means,
said second cone contained in said outlet means, the distance
between the narrow ends of said first and second cones being about
equal to the inside diameter of said exhaust means, and said outlet
means communicated from the operating room to a venting channel,
wherein the pressurized gas passes between said first and second
cones thereby creating suction and removing the anaesthetic gas
from said exhaust means;
said flowmeter and regulating valve communicated to said branched
pipe and communicated and attached to said exhaust means of said
vacuum means, the downstream portion of said flowmeter defining
said exhaust means;
said rubber bag for controlled administration of the anaesthetic
gas to and communicated with said mask;
said check valve provided for one-way flow between and communicated
with said rubber bag and said mask;
said mask for administration of the anaesthetic gas to the patient
and communicated to said inlet means;
an additional check valve provided for one-way flow between and
communicated with said rubber bag and said inlet means;
the entire system being closed such that at least a portion of the
return anaesthetic gas leaving said mask is substantially
continuously exhausted away from the area in which said apparatus
is operated.
2. Apparatus as claimed in claim 1 including a respirator, a
reservoir bag communicated to the exhaust side of said respirator,
said reservoir bag communicated with said vacuum means.
3. Apparatus as claimed in claim 1 wherein said inlet means is
provided with a valve means for the control of said pressurized gas
to said ejector suction unit.
4. Apparatus as claimed in claim 1 wherein a water absorption means
is provided upstream from and communicated to said flowmeter.
5. Apparatus as claimed in claim 4 wherein said water absorption
means includes silica gel.
6. Apparatus as claimed in claim 4 wherein said water absorption
means is provided with a quick exchange means for rapid removal and
replacement of the water absorption material contained therein.
Description
BACKGROUND OF INVENTION
The invention relates to a plant or apparatus preferably for
anaesthesia including a pipe system to which there are connected an
anaesthetic mask, an absorber for the absorption of the carbon
dioxide of the expiration air, a rubber bag, check valves and an
inlet for feeding the anaesthetic gas from a rotameter box.
A plant of this kind is already known, in which a respiration valve
of the pop-off type is fitted in the pipe system at the rubber bag.
In this valve the excess anaesthetic gas from the system will
gradually pass out to the room in which the apparatus is used which
is most undesirable as there is reason to believe that the
anaesthetics generally used today have a teratogenetic effect. It
has been found, for example that prolonged exposure to nitric oxide
may bring about aplastic anaemia, and among American
anaesthesiologists there seems to be a noteworthy death-rate due to
malignant tumours in the blood cell forming organs. Studies of
Danish anaesthesia staff has proven that the frequency of
spontaneous abortion rose from 10 to about 20 per cent after
employment in an anaesthesia department as compared to working in
areas free from anaesthetics.
Also in anaesthesia plants with no respiration valve anaesthetic
gases will escape. This has for instance been ascertained by the
fact that members of hospital staffs who have stayed in a room
where fluothane (bromochlorotic fluoroethane) anaesthesia is given
will show detectable quantities of fluothane in their expiration
air up to half an hour after they have left the room. Headaches and
tiredness after a day's work in an operating room are known by all
anaesthesiologists.
One would think that it would suffice to guide the anaesthetics
gases down to floor level to get rid of them at head level, but
this measure has not always proved to be adequate. The anaesthetics
gases are capable of quickly spreading upwards thereby affecting
those staying near the plant.
SUMMARY OF INVENTION
On this background, the purpose of the invention is to produce a
plant of the above-mentioned kind which results in complete removal
of the anaesthetic gas leaving the pipe system.
The plant according to the invention is characterized in that the
pipe system, preferably near the rubber bag, has a branch pipe
which is provided with parts for the controlled suction of the
anaesthetic gases from the pipe system. In this way control is
maintained of the anaesthetic gases which have left the pipe system
of the plant, whereby those members of the hospital staff operating
the device or being near it are prevented from being exposed to the
injurious effect of the gases.
According to the invention the devices for controlled suction of
the anaesthetic gases may comprise a flowmeter provided with a
regulating valve, the outlet of the meter being connected with a
vacuum producing or vacuum means, such as a vacuum pump or a
central vacuum plant. Easy adjustment of the volume current desired
to remove from the circuit is realized as well as during the
adjustment of the valve it is easy to take readings of the
flowmeter. The adjustment of the valve must be suited to the volume
current of the anaesthetics gas which is fed from the rotameter box
so that a balance is maintained between the volume current
introduced and the volume current exhausted. Besides the flowmeter
is easy to control.
As the flowmeter is only in contact with the expiration air of the
patient, there will be no disinfection problem connected with the
plant.
Further according to the invention, a humidity absorber may be
inserted before the flowmeter, and the flowmeter may for instance
be of the rotameter type or it may be a ball flowmeter. Hereby a
marked reliability is achieved as the float or ball of the
flowmeter is kept free from moisture.
Further according to the invention the humidity absorber may
contain silica gel as known, and the quantity of this gel may be at
minimum 20 g. This is sufficient for a flowmeter of the rotameter
type will work perfectly for at least three hours under normal
suction conditions. Also according to the invention the flowmeter
may be built into the rotameter box whereas the humidity absorber
is fitted adjacent to the box. In this manner it is easy to read
the magnitude of the volume current removed and applied and also
that the silica gel is easy to exhange. The exchange may be
conveniently performed during the working of the plant.
According to the invention the plant may be arranged to work in
connection with a respirator, the suction devices being fitted on
the expiration side of the respirator, and also a reservoir bag may
be fitted between the respirator and the suction devices. Thereby a
most reliable working of the respirator and a careful removal of
the expiration air is achieved.
Also according to the invention the humidity absorber may be fitted
for an easy exchange by providing it with a quick clutch. Thus the
humidity absorber is very easy to remove and replace with another
when the absorbability of the gel contained has been used up.
Usually, this will be shown when an indicator added to the gel
changes color.
Further according to the invention the vacuum producing unit may be
designed as an ejector suction unit and built together with the
flowmeter at its outlet end, and the outlet end of the ejector
suction unit may be connected to a piping carried to the nearest
window or venting channel in the working room. In this way the
suction can be carried out very smoothly as a result of the
continuously flowing driving gas. In practice heat does not occur,
and the unit is working completely independent of an electric power
supply. Incidentally it must be observed that the anaesthetic gas
leaving the flowmeter is not exhausted into the working room. Thus,
the staff operating the plant is well protected against the
anaesthetic gas.
According to the invention the ejector suction unit may consist of
a mainly T-shaped pipe piece, the vertical part of which is tightly
fitted to the outlet end of the flowmeter, and the horizontal part
of which contains two mainly truncated cone-shaped jet bodies, The
narrowest ends of these bodies face each other and have a mutual
distance which generally is equal to the inside diameter of the
vertical pipe part, and where the narrowest end of the jet body
acting as jet pipe projects a just over the inside diameter of the
vertical pipe part, and that the horizontal pipe part is provided
with means for inlet and outlet, respectively of the driving gas.
This ejector suction unit is both simple and reliable.
According to the invention additionall in the horizontal part of
the T-shaped pipe piece a shut-off valve may be inserted, such as a
ball valve and this valve may be fitted upstream from the jet body
formed by the jet pipe, in the supply direction of the driving gas.
In this manner the suction unit is easy to start and stop without
it being necessary to regulate the source from which the driving
gas is supplied
Finally, according to the invention the injector suction unit may
be arranged to work with a driving gas having a pressure of up to 6
atmospheres, which gas may for instance be compressed air, nitrogen
or oxygen. The vacuum thus produced by the suction unit will be
suitably high .
DESCRIPTION OF THE DRAWINGS
The invention is explained in the following with reference to the
drawing where
FIG. 1 shows in outline an embodiment of the plant according to the
invention intended for anaesthesia,
FIG. 2 a flowmeter provided with a regulating valve with humidity
absorber,
FIG. 3 the plant according to the invention used in connection with
a respirator,
FIG. 4 another embodiment of the plant according to the invention
intended for anaesthesia, and in which the anaesthetic gas is
removed by means of an exhaust suction unit,
FIG. 5 a flowmeter provided with a regulating valve with requisite
humidity absorber and exhaust suction unit, seen in perspective,
and
FIG. 6 part of the exhaust suction unit according to FIG. 5 in a
large scale and longitudinally viewed.
DESCRIPTION OF PREFERRED EMBODIMENTS
The anaesthesia plant shown in FIG. 1 consists of a flow sytem 1,
in which are arranged an anaesthetic mask 2, a check valve 3, a
pipe stub 4 for feeding fresh anaesthetic gas, a carbon dioxide
absorber 5, a branch pipe 6, a rubber bag 7, and another check
valve 8. When the plant is working, the anaesthetic gas will flow
in the direction indicated by the arrows, the valve operator
periodically compressing the rubber bag 7.
In the branch pipe 6 devices are fitted for controlled suction of
the anaesthetic gas from the system, and these devices are made up
of a flowmeter provided with a regulating valve and a vacuum
producing unit 11, for instance a central vacuum plant or a vacuum
pump.
FIG. 2 shows in detail how the flowmeter, which is of the rotameter
type, is constructed. It has at the bottom a regulating valve 9,
which may be designed as a needle valve. This valve rests on, in a
known manner, an inlet pipe communicated with a metering pipe
extending up around the longitudinal axis of the flowmeter. The
inside of this pipe communicates with an outer space around the
metering pipe, and this outer space communicates with an outlet
pipe 6a below the level of the valve 9. The pipe 6a is connected
with the vacuum unit 11. The flowmeter is connected at its inlet
end with a humidity absorber 12 in the form of a water absorber
containing silica gel 13 (for example 20 grams) as an absorption
means. The absorber is made of a thermoplastic material and has an
open top and a perforated bottom. By means of the rod 14 it is
possible to empty the water absorber. The anaesthetic gas coming
from the pipe system 1 in FIG. 1 passes through the branch pipe 6
up to the top of the water absorber 12 whereupon it passes down
through the silica gel. At the bottom end of the water absorber the
gas runs into the flowmeter and passes next upwards through the
metering pipe and back along its outer side. The float of the
flowmeter will during this passage take up a certain position of
equilibrium, it being partly affected by the gas and partly by
gravitation. Readings of the flowmeter can then be taken. From the
flowmeter the gas flows further on to the vacuum unit. It is
observed that the vacuum unit supplies a constantly low suction,
for instance 50 mm Hg. When a certain flow of anaesthetic gas is
required to be removed from pipe system 1, the regulating valve 9
is adjusted, until the flowmeter indicates the value desired. This
value shall be of a suitable ratio to the flow of fresh anaesthetic
gas, which from the rotameter box 16 is carried forward to the
inlet 4 of the system 1. As shown in FIG. 2, the flowmeter may be
combined with the rotameter box 16. The water absorber 12 is placed
outside the box as the silica gel must be easily exchanged. Such an
exchange is required when a color indicator added to the silica gel
shows that it no longer absorbes water. It is possible to replace
the gel even if the plant is in operation. The humidity absorber
may be provided with a quick clutch so that it is easy to remove
and renew.
When the flowmeter is properly adjusted, the rubber bag 7 will not
be completely filled as in the case of the usual system with a
respiration valve. This means that the only resistance which the
patient is respiring against is the resistance found in the check
valves.
The above flow system 1 is shown in the form of a circuit. However,
there is nothing to prevent the plant from consisting of a
gas-conduction conduit to which the anaesthetic mask, and, if any,
an absorber, a rubber bag and optionally one or more check valves
are also connected with the suction devices.
The plant described above may be conveniently used in connection
with a respirator 170, which appears from FIG. 3. A branch pipe 180
is partly connected to the expiration side of the respirator and
partly connected to the suction devices in the form of a flowmeter
190 and a vacuum means 200. The vacuum means 200 may be located in
a room outside the one in which the respirator and the flowmeter
are erected, which is indicated by means of the dotted line 205.
Between the respirator and the flowmeter a reservoir bag 210 is
inserted for provisional storing of the expiration air from the
patient, which air pulsating is carried out into the pipe 180.
Instead of the flowmeter it will suffice in certain cases to use a
throttle valve.
The embodiment of the anaesthesia plant according to the invention
as shown in FIG. 4 consists as in FIG. 1 of a flow system 1 in
which there is an anaesthetic mask 2, a check valve 3, an inlet 4
for feeding fresh anaesthetic gas, a carbon dioxide absorber 5, a
branch pipe 6, a rubber bag 7 and another check valve 8. When the
plant is working, the anaesthetic gas will flow in the direction
indicated by the arrows, the valve operator periodically
compressing the rubber bag 7.
In the branch pipe 6 suction devices are fitted in the form of a
flowmeter 10 and an ejector suction unit 17, the latter being
fitted on the outlet end of the flowmeter. The ejector suction unit
is fed with driving gas from a suitable driving gas source 18,
which is under pressure. This source may for instance consist of a
pressure tank, as shown in FIG. 5, but may also consist of a
compressed air plant. The driving gas used in the unit 17 is drawn
away via a piping 20 carried to the nearest window or a venting
channel 21 in the working room, in which the plant is in
operation.
In FIG. 5 is shown how the ejector suction unit 17 is built
together with the flowmeter 10. As will be seen, the flowmeter is
held in position between an upper and a lower bar 22 and 23 in a
rectangular frame, and it consists as in FIG. 2 of a jacket pipe
10a and a metering pipe 10b placed inside the former. The top end
of the metering pipe 10b', the outlet end, is connected with a
vertical pipe part 17a in a T-shaped pipe piece in the ejector
suction unit. The horizontal part of this pipe piece carries, as
shown in FIG. 6, the reference number 17b, and consists of two
substantially truncated coned jet bodies 20 and 21, the narrowest
ends of which 20' and 21' are facing each other. The distance a
between these ends is substantially equal to the inside diameter of
the pipe part 17a. As will be seen, the end 20' projects a little
over the inside diameter of the pipe part 17a. In the pipe part
17b, a shut-off valve 29, as shown in FIG. 5, is inserted, such as
a ball valve. At each end of the pipe part 17b there are stubs 24
and 25 for admitting and exhausting the driving gas.
Upstream from the flowmeter there is, as shown in FIG. 5, a
humidity absorber 12 inserted which for instance may contain the
silica gel. This absorber is connected by means of a pipe 26 to the
space between the jacket pipe 10a and the metering pipe 10b of the
flowmeter. The stub 27 of the absorber is connected with the branch
pipe 6 shown in FIG. 4.
At the lower end of the metering pipe 10b, as shown (FIG. 5) a
regulating valve 9 is inserted, whereby the flow of the anaesthetic
gas through the metering pipe may be easily regulated or shut off.
The flowmeter 10, being of the rotameter type, contains a float
which, in a known manner, indicates the magnitude of the volume
flow passing.
The apparatus shown in FIGS. 4-6 functions in the following way:
When the plant is in operation, anaesthetic gas is fed to the pipe
system 1 via the inlet 4 connected to the rotameter box. At the
same time gas is being sucked out through the branch pipe 6, in a
manner such that the variations of the anaesthetic gas pressure in
the system 1 will be very small, probably less than one-half cm in
a water column. The suction evacuation is brought about by means of
an ejector suction unit 17, having driving gas passed therethrough
as shown by the arrows A in FIG. 5. The driving gas, which may have
a pressure approaching up to 6 atmospheres, is converted by the jet
body 20 into a thin gas stream impinging upon the opening at the
lower end 21' of the jet body 21 as this gas stream travels
forward, it will expand creating a lower pressure. The lower
pressure will have the effect of sucking the anaesthetic gas from
the metering pipe 10b of the flowmeter. Before the anaesthetic gas
has reached this stage, it has, as shown by the small arrows,
passed through the silica gel in the absorber 12 so that it is
rather dry. This will cause the flowmeter to work most precisely.
The exhaust volume flow can be regulated either by the valve 9 or
by reducing the pressure of the driving gas at the pipe stub
24.
As driving gas many different gases can be used, such as for
instance compressed air, nitrogen or oxygen.
When the exhaustion is done in the way described above, there is no
danger of the anaesthetic gases removed exploding as the gases will
not be exposed to any significant amount of heat nor is the
formation of sparks likely. Besides the exhaustion is carried out
very smoothly, the driving gas passing continuously through the
pipe piece 17b.
There are several other embodiments of the present invention. For
example, the jet bodies 20 and 21 may have a larger or smaller
vertex angle than the one shown. Also the distance between the
bodies may be made shorter than shown.
The plants described above serve only to illustrate the invention
and not to limit the scope thereof.
* * * * *