U.S. patent number 3,640,276 [Application Number 05/001,745] was granted by the patent office on 1972-02-08 for apparatus for making intravenous or intra-arterial injections.
This patent grant is currently assigned to Allis-Chalmers Manufacturing Company. Invention is credited to Robert C. Dancy, Jr..
United States Patent |
3,640,276 |
Dancy, Jr. |
February 8, 1972 |
APPARATUS FOR MAKING INTRAVENOUS OR INTRA-ARTERIAL INJECTIONS
Abstract
An apparatus for and method of making intravenous or
intra-arterial injections such as forced blood transfusions or the
like. In a preferred embodiment of the apparatus a modular
construction is provided including a first housing unit for the air
pressure chamber which receives the flexible blood container or the
like and subjects it to a predetermined controlled air pressure.
The modular assembly may include a second housing unit for a plenum
chamber in fluid communication with the pressure chamber through an
air pressure regulator. A third housing unit may be provided to
receive an air compressor for supplying the plenum chamber with
air. The plenum chamber may also be charged either from the
hospital air supply or by the compressor with sufficient air for a
predetermined number of blood transfusions and used in conjunction
with the air pressure regulator and pressure chamber as a portable
subassembly. In another modification, the pressure chamber or a
pressure cuff may be connected directly to the hospital air supply
through the air pressure regulator without using a plenum chamber
in the system.
Inventors: |
Dancy, Jr.; Robert C.
(Brookfield, WI) |
Assignee: |
Allis-Chalmers Manufacturing
Company (Milwaukee, WI)
|
Family
ID: |
21697636 |
Appl.
No.: |
05/001,745 |
Filed: |
January 9, 1970 |
Current U.S.
Class: |
604/141; 222/61;
128/DIG.13; 222/399 |
Current CPC
Class: |
A61M
5/1486 (20130101); Y10S 128/13 (20130101) |
Current International
Class: |
A61M
5/145 (20060101); A61M 5/148 (20060101); A61m
005/00 () |
Field of
Search: |
;128/213,214,214.2,215-216,225,DIG.13
;222/94,96,95,105,61,386.5,399,389 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. An apparatus for use in administering intravenous or
intra-arterial liquid injections comprising a pressure chamber, a
flexible or pliable container which holds the liquid to be
injected, said container being positioned in said pressure chamber,
means extending from said container to the exterior of said
pressure chamber for connecting said container in transfusing
relation to a patient, a gas supply, conduit means connecting said
gas supply to said pressure chamber, gas pressure regulating means
interposed in said conduit means for regulating the pressure of gas
admitted to said pressure chamber, said pressure chamber including
a closure member movable to an open position to permit access to
the interior of said pressure chamber, said conduit means being
provided with an on-off valve which in off position interrupts
fluid communication between said gas supply and said pressure
chamber, and means interlocking said valve with said closure member
whereby said valve is moved to said off position upon movement of
said closure member to open position.
2. An apparatus for use in administering intravenous or
intra-arterial liquid injections comprising a pressure chamber
housing unit having a pressure chamber therein, a flexible or
pliable container which holds the liquid to be injected, said
container being positioned in said pressure chamber, means
extending from said container to the exterior of said pressure
chamber for connecting said container in transfusing relation to a
patient, a plenum chamber housing unit, said plenum chamber housing
unit containing a plenum chamber for storing gas to be admitted to
said pressure chamber, said plenum chamber being adapted to be
connected to a source of gas supply, said pressure chamber housing
unit and said plenum chamber housing unit being engageable with
each other in a modular assembly, conduit means connecting said
plenum chamber to said pressure chamber, gas pressure regulating
means interposed in said conduit means for regulating the pressure
of gas admitted to said pressure chamber, said pressure chamber
housing unit including a closure member movable to an open position
to permit access to the interior of said pressure chamber, said
conduit means being provided with an on-off valve which in off
position interrupts fluid communication between said plenum chamber
and said pressure chamber, and means interlocking said valve with
said closure member whereby said valve is moved to said off
position upon movement of said closure member to open position.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for and method of making
intravenous or intra-arterial injections, such as blood
transfusions.
2. Description of the Prior Art
In the administration of intravenous fluids such as blood to the
body, it is often necessary to accelerate the flow. For example, in
the administration of blood during surgery or after an accident it
is often desirable to administer previously collected blood at
faster rates than gravity flow permits. For a considerable period,
it has been known to employ for this purpose manually operable
blood pumps which operate on the "squeeze bulb" principle. A
disadvantage of the manually operated pumping devices heretofore
utilized is that they do not provide an easily measurable uniform
pumping action on the blood so that the administrator can regulate
the rate at which blood is being transfused. It is also known to
provide positive pumping arrangements for pumping blood at
controlled rates, as illustrated by U.S. Pat. No. 3,052,238--issued
to C. R. Broman et al. on Sept. 4, 1962, and No. 3,425,415--issued
to E. S. Gordon et al. on Feb. 4, 1969.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an adjustable automatic
pressure regulating system for intravenous or intra-arterial
injections or the like which may be used, for example, for
transfusing human blood under forced constant flow conditions.
It is a further object of the invention to provide an apparatus for
and a system of making intravenous or intra-arterial injections or
the like such as forced blood transfusions, using integrated
modular components, and including an adjustable automatic pressure
regulator, and in which various numbers of modules and various
arrangements of modules may be used in different embodiments of the
invention.
It is a further object of the invention to provide an apparatus for
and method of making intravenous or intra-arterial injections or
the like such as blood transfusions, for example, in which the gas
or air pressure applied to the fluid being transfused may be
derived from the hospital gas or air supply, which gas supply in
accordance with the invention is subjected to adjustable automatic
pressure regulation before being applied to the fluid being
transfused.
In describing the invention, air will be cited as the type of gas
used as the pressure medium, and in most cases air would be the gas
used for this purpose. However, it will be understood that other
suitable gases could be used for this purpose. Also, the invention
will be described as embodied in an apparatus for and method of
intravenously transfusing blood or other intravenous fluids.
However, it will be understood that the apparatus and method are
equally applicable for use in connection with the intra-arterial
injection of blood, although higher gas pressure values would be
required for intra-arterial injections than for intravenous
injections.
In achievement of these objectives, there is provided in accordance
with this invention an apparatus for and method of making
intravenous or intra-arterial injections such as forced blood
transfusions. In a preferred embodiment of the apparatus a modular
construction is provided including a first housing unit for the air
pressure chamber which receives the flexible blood container or the
like and subjects it to a predetermined controlled air pressure.
The modular assembly may include a second housing unit for a plenum
chamber in fluid communication with the pressure chamber through an
air pressure regulator. A third housing unit may be provided to
receive an air compressor for supplying the plenum chamber with
air. The plenum chamber may be charged either from the hospital air
supply or by the compressor with sufficient air for a predetermined
number of blood transfusions and used in conjunction with the air
pressure regulator and pressure chamber as a portable subassembly.
In another modification, the pressure chamber or a pressure cuff
may be connected directly to the hospital air supply through the
air pressure regulator without using a plenum chamber in the
system.
Further objects and advantages of the invention will be apparent
from the following description taken in conjunction with the
accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an operational schematic diagram of a forced blood
transfusion system in accordance with the invention;
FIG. 2 is an external perspective view of a modular apparatus for
use with the system of FIG. 1;
FIG. 3 is another external view from a different angle of the
modular apparatus of FIG. 1, and showing the cover member of the
pressure chamber partially open;
FIG. 4 is a view in longitudinal section of the apparatus of FIGS.
2 and 3;
FIG. 5 is a fragmentary view in longitudinal section of the modular
apparatus of FIGS. 2-4, inclusive, showing details of the latching
and interlock mechanism associated with the cover member of the
pressure chamber;
FIG. 6 is a fragmentary view showing details of the quick
detachable connection of the pressure regulator and of the filter
to the wall of the pressure chamber of the modular apparatus of
FIGS. 2-5, inclusive;
FIG. 7 is a schematic operational diagram of a modified embodiment
of the invention;
FIG. 8 is a detail view of the inlet fitting to the pressure
chamber which may be connected to a flexible conduit leading to the
plenum chamber or which may alternatively be connected to a
flexible conduit leading to a manually operated ball pump which may
be used to manually supply pressure to the pressure chamber;
FIG. 9 is a detail view of a blowout seal which may be used to
prevent excessive pressure in the pressure chamber and in the
plenum chamber;
FIG. 10 is a front elevation view of a pressure cuff which may be
used to apply pressure to the flexible blood container or the like;
and
FIG. 11 is a view in transverse section along line XI--XI of FIG.
10 showing the flexible blood container being supported by the
pressure cuff.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1 which shows an operational schematic for a
forced blood transfusion system in accordance with the invention,
there is shown a conduit generally indicated at 10 including an
inlet end 12 which may be connected to a compressor generally
indicated at 16 which may form part of the modular apparatus to be
described hereinafter.
As will be described in more detail later and as seen schematically
in FIG. 1, air from compressor 16 passes into accumulator or plenum
18 which serves as a reservoir or storage chamber for air which
passes through filter 24, regulator 26 and on-off valve 30 to
pressure chamber 32.
Instead of using compressor 16 as a source of air supply, and as
seen schematically in FIG. 1, the hospital air supply generally
indicated at 14 in FIG. 1 may be used as an air supply. The
hospital air supply may be connected directly to the input of the
filter-regulator subassembly 24-26 as at 25A from whence the air
passes through on-off valve 30 to the pressure chamber 32. In this
case, accumulator or plenum chamber 18 is disconnected from the
system. Alternatively, the hospital air supply 14 may be connected
to inlet 12 as at 12A to charge up accumulator or plenum chamber 18
with sufficient air to service a plurality of blood transfusion
units, such as 12 units, for example. After the plenum chamber 18
has been charged as just described, it is disconnected from the air
supply and the combination of the charged plenum chamber 18 and the
pressure chamber 32 may be used as a portable subassembly for
administering a plurality of intravenous injections.
The accumulator generally indicated at 18 and which may be embodied
as the plenum chamber to be described hereinafter as part of the
modular apparatus, is connected in fluid communication with conduit
10 a short distance downstream of inlet connection 12, accumulator
18 being connected to conduit 10 by means of a tubular connection
19. A pressure indicator 20 is connected in fluid communication
with the interior of accumulator 18 whereby to indicate the fluid
pressure internally of accumulator 18. A blowout seal 22 is
provided in the wall of accumulator 18 to permit pressure relief at
a predetermined pressure internally of the accumulator. A filter 24
is connected in series fluid communication with conduit 10
downstream of accumulator 18 whereby to filter out any impurities
in the air or other fluid being conducted through conduit 10 before
the air reaches the regulator. An automatic pressure regulator
generally indicated at 26 is connected in series with conduit 10
downstream of filter 24. The pressure regulator is capable of
regulating the input air pressure thereto to provide a predetermine
output air pressure at the outlet end of the regulator, and the
value of outlet pressure to be maintained by the regulator may be
adjusted by means of adjusting knob 28 to provide a desired value
of output pressure. Despite any fluctuations in input gas pressure
from the source of supply, regulator 26 maintains a constant output
pressure, assuming that a sufficient pressure differential is
maintained across the regulator to satisfy the dynamic requirements
of regulation, as is well known in the art of gas pressure
regulation. For example, the regulator may maintain an output
pressure within a range of 0 to 500 millimeters of mercury with an
air flow rate in the range of 2 to 20 milliliters per second.
The pressure regulator 26 may be of any suitable commercially
available type and, for example, may be a Fairchild-Hiller part
catalog 10122, Model 10 precision regulator.
This air pressure regulator is a product of Fairchild-Hiller
Industrial Products Division, 1501 Fairchild Drive, Smith Reynolds
Airport, Winston-Salem, N.C. 27105, and is described in a
Fairchild-Hiller bulletin identified as "W.P. Co. 8876-4-67."
Another air pressure regulator which may be used is Regulator No.
3R06-100-RNE produced by Beckett-Harcum Co., 985 West Locust St.,
P.O. Box 809, Wilmington, Ohio 45177, and described in
Beckett-Harcum Catalog ALC, printed Jan., 1968.
The output fitting of regulator 26 is connected to conduit 10, and
an on-off valve 30 is connected in series with the portion of
conduit 10 extending from the outlet end of regulator 26 to the
inlet end of the pressure chamber generally indicated at 32 in
which the blood container 38 is received. The regulator 26 should
be of the "bleeding" type. This may be accomplished by providing an
air leakage or "bleeding" hole in the regulator 26 or in the
conduit portion 10C upstream of on-off valve 30. This permits the
output pressure maintained by the regulator to be adjusted from a
given output pressure value to a lower value. Valve 30 should be
moved to closed position when the pressure setting to be maintained
by the regulator is being readjusted to a different value by
rotation of control knob 28. As will be explained later, on-off
valve 30 is suitably interlocked with movable cover member 34 of
the pressure chamber 32 in such manner that when cover 34 is moved
to open position, valve 30 is automatically moved to closed
position, whereby to interrupt the fluid connection between
regulator 26 and pressure chamber 32. A suitable pressure indicator
36 is interposed in conduit 10 between the regulator 26 and on-off
valve 30 to provide a reading of the injection pressure in pressure
chamber 32, and to indicate the preset pressure existing in conduit
10C when on-off valve 30 is in the closed position.
A flexible or pliable blood container 38 in the form of a sterile
plastic bag or the like containing 500 milliliters of blood (the
standard unit) is positioned in pressure chamber 32 and is
subjected to the air pressure inside chamber 32. A flexible conduit
40 having a hypodermic needle termination is inserted through a
rubber or plastic plug in blood container 38. The flexible conduit
40 connected to blood container 38 passes through a suitable sealed
aperture in the wall of chamber 32 and is connected to a suitable
drip device 42 used in administering blood or other intravenous
liquid material to the patient.
Referring now to FIGS. 2-5, inclusive, there is shown a modular
construction which may be utilized to house the various components
of the system of FIG. 1. Thus, in FIGS. 2-5 inclusive, there is
shown a modular assembly generally indicated at 50 comprising an
integrated interlocked assembly of three housing units of generally
polyhedral shape including a compressor housing unit 16', a plenum
chamber housing unit 18', and a pressure chamber housing unit 32'.
Each of the housing units 16', 18' and 32' has the same shape in
horizontal cross section and is of the same peripheral shape to
permit vertical stacking of the intermediate or plenum chamber
housing unit 18' on top of the compressor housing unit 16' and to
permit stacking of the pressure chamber housing unit 32' on top of
the intermediate housing unit 18', as best seen in the views of
FIGS. 2 and 3.
As best seen in the view of FIG. 4, the upper edges of the four
sidewalls of the compressor housing unit 16' are rabbeted as
indicated at 52, and the interfitting lower portions of the four
sidewalls 54 of the plenum housing unit 18' are so dimensioned as
to be received in interfitting relation to the rabbeted portions 52
of the compressor housing unit 16'. In a similar manner, the upper
edges of the four sidewalls of the plenum housing unit 18' are
rabbeted as indicated at 56, and the corresponding lower edges of
the sidewalls 58 of the pressure chamber housing unit 32' are
dimensioned to properly interfit with the rabbeted edges of the
plenum housing unit 18'. It will be understood, of course, that the
bottom, top, and sidewalls of the plenum chamber housing unit 18'
enclose the plenum chamber 18; and that similarly the bottom, top
and sidewalls of the pressure chamber housing unit 32' enclose the
pressure chamber 32. The bottom walls of plenum chamber housing
unit 18' and of pressure chamber housing unit 32' are spaced above
the lower ends of the sidewalls of the respective housing units 18'
and 32'.
As best seen in the view of FIG. 4, the compressor housing unit 16'
is provided with a suitable fluid outlet fitting 60 which is
suitably connected to the output of the compressor 16 contained
within compressor housing unit 16'. The plenum chamber housing
section 18' is provided with a suitable fluid inlet fitting 62.
When the compressor is being used to supply air to plenum chamber
18, a suitable flexible conduit 64 is connected between fluid
outlet fitting 60 of compressor housing unit 16' and fluid inlet
fitting 62 of plenum housing unit 18' . Fluid inlet fitting 62
includes a check valve 63 which permits fluid flow into plenum
chamber 18 but prevents reverse flow therefrom. In a similar
manner, plenum housing unit 18' is provided with a fluid outlet
fitting 66 and pressure chamber 32 is provided with a suitable
fluid inlet fitting 68. Outlet fitting 66 of chamber 18
incorporates a suitable manually operated shutoff valve 67 which
can be moved to closed position when required. When plenum chamber
18 is being used as a source of air supply for pressure chamber 32
as shown in the operational schematic system of FIG. 1, and as
shown in the assembled views of FIGS. 2, 3 and 4, fluid outlet
fitting 66 of plenum chamber 18 is connected by flexible conduit
10A to the inlet fitting 25 leading to filter 24, the output of
filter 24, in turn, being connected by flexible conduit 10B to the
input of air pressure regulator 26. Inlet fitting 25 includes a
check valve 29 which permits fluid flow into filter 24 moving
toward regulator 26 and pressure chamber 32, but prevents fluid
flow in the reverse direction. The output of regulator 26 is
connected by flexible conduit 10C to the input side of on-off valve
30 which is mounted on forward wall 32' A of pressure chamber
housing unit 32' (FIG. 2). Conduit section 10D connects the output
side of valve 30 to the input fitting 68 of pressure chamber 32.
Input fitting 68 of chamber 32 incorporates a check valve 73 which
prevents reverse flow of gas from pressure chamber 32. The position
of valve 30 is controlled by the interlock arrangement with cover
34 of pressure chamber 32 as will be described in more detail
hereinafter.
As best seen in the view of FIG. 6, regulator 26 may be detachably
connected by a clip connection or the like to the inside surface of
one of the sidewalls of pressure chamber housing unit 32' below
bottom wall 37 of the pressure chamber 32. Filter 24 may be
detachably connected in the same manner as the regulator. This
permits easy attachment and detachment of regulator 26 and filter
24 when desired, thereby facilitating maintenance of the filter and
the regulator. Suitable access means (not shown) may be provided in
the various housing sections for making the necessary conduit and
component connections.
As seen in FIGS. 2 and 5, the combination cover latching and
interlock arrangement for valve 30 is mounted on the front wall 32'
A of pressure chamber housing unit 32' . Cover or closure member 34
of the pressure chamber is pivotally connected at one end at 70 for
pivotal movement about a normally horizontal axis, and is provided
at its opposite end with a cover detent member 72 which is rigidly
fixed to and movable with cover 34. Detent member 72 includes a
rearwardly extending portion 74 which is adapted to cooperate with
a latching mechanism generally indicated at 76 supported by front
wall 32' A of pressure chamber housing unit 32' . A pair of
laterally spaced bearing bracket numbers 78 are mounted on the
forward surface of wall 32' A of pressure chamber housing unit 32'
. A shaft 80 is supported for rotary angular movement by laterally
spaced bearing brackets 78. On-off valve 30 is connected to or
forms a part of one end of shaft 80 in such manner that rotation of
shaft 80 is effective to move valve 30 from its "on" to its "off"
position or vice versa depending upon the direction of rotation of
shaft 80. An operating handle 82 is connected to shaft 80 whereby
rotation of handle 82 is effective to impart a rotary angular
movement to shaft 80. A flexible latching member 83 formed of
spring steel or the like has one of its ends fixed to shaft 80 as
indicated at 84 and a portion of the length of flexible latching
member 83 in the closed or latched position of cover 34 is wound
around a portion of the periphery of shaft 80 as best seen in the
view of FIG. 5. Flexible member 83 includes a tongue portion 83'
which overlies portion 74 of detent member 72 in the position of
the members as seen in FIG. 5. As shaft 80 is moved in a clockwise
direction with respect to the view in FIG. 5 toward an unlatched
position of the mechanism, a portion of the length of flexible
connector 83 is payed out and rolls off of the periphery of shaft
80. A guide or cam slot 86 is provided in a corresponding portion
of each of the oppositely disposed brackets 78, and a pair of
oppositely extending pintles 88 are carried by flexible latching
member 83 intermediate the length thereof and are received in and
guided by cam slots 86 in brackets 78. Each cam slot 86 is inclined
vertically upwardly to the right toward the forward wall 32'A of
pressure chamber housing unit 32'. Thus, in moving upwardly in
slots 86, pintles 88 also move to the right with respect to the
view of FIG. 5.
In the position of the members as shown in FIG. 5, cover 34 is
closed and the latching mechanism is in a position in which a
portion of the length of flexible latching member 83 is wound about
shaft 80. To open cover member 34, shaft 80 is rotated by means of
handle 82 in a clockwise direction with respect to the view of FIG.
5 to cause flexible latching member 83 to move upwardly as it
initially unwinds from shaft 80. During the initial portion of the
movement of flexible latching member 83, member 83 and tongue
portion 83' thereof move in a substantially vertical direction with
tongue portion 83' still being in overlying relation to rearwardly
extending portion 74, whereby the force of the contained air
pressure exerted on cover 34 causes the cover to move upwardly for
a short distance without being fully released, but sufficiently to
release the air pressure within pressure chamber 32.
The initial rotary movement just described of shaft 80 in an
opening direction is also effective to move on-off valve 30 to a
position in which the valve is in an "off" position to prevent
fluid communication between the accumulator or plenum chamber 18
and regulator 26 on the one hand, and the interior of pressure
chamber 32 on the other hand. Thus, in the same initial movement
which permits cover 34 to be moved to a venting position, valve 30
is moved to a closed position. The interlock arrangement just
described between cover 34 and on-off valve 30 automatically
isolates pressure chamber 32 from the air supply line 10C from
regulator 26 when changing to a new unit 38 of blood.
Further rotation of shaft 80 in a clockwise direction, with respect
to the view shown in FIG. 5, beyond the initial movement just
described causes the cam or guide tracks 86 to constrain flexible
latching member 82 to move sufficiently to the right with respect
to the view shown in FIG. 5 whereby to move tongue portion 83' of
member 83 out of overlying relation to rearwardly extending portion
74 of cover latch member 72. This movement of tongue portion 83'
out of the path of latch portion 74 as just described permits cover
34 of pressure chamber 32 to be manually lifted to a completely
open position to permit replacement of blood container 38, if
desired.
Thus, it will be seen that the latching assembly for cover 34 not
only has its movement interlocked with on-off valve 30 to insure
that valve 30 is moved to a closed position in the initial opening
movement of the cover, but also cover 34 is movable to an open
position in two distinct steps, namely, a first step in which latch
member 83 is moved to a position which permits cover 34 to be
manually moved to a venting position but in which tongue portion
83' of latch member 83 is still in overlying relation to portion 74
of latch member 72; and a second step or position in which latch
portion 83' is moved out of overlying relation to latch portion 74
and in which cover 34 can then be manually moved to a completely
open position.
As best seen in the views of FIGS. 2 and 3, the pressure gauge 20
which indicates the pressure in plenum chamber 18 is mounted on the
forward wall 18'A of plenum chamber housing unit 18'. Pressure
gauge 36 which measures the pressure in conduit section 10C leading
to pressure chamber 32 is mounted on a sidewall of pressure chamber
housing unit 32'. Adjusting knob 28 for adjusting air pressure
regulator 26 to regulate or maintain the desired pressure in
pressure chamber 32 is mounted on or projects through an opening in
a wall of the pressure chamber housing unit 32'. Blowout seal 35 of
pressure chamber 32 is mounted in a sidewall of the pressure
chamber housing unit 32'; and blowout seal 22 of plenum chamber 18
is mounted in a sidewall of plenum chamber housing unit 18'.
When the three housing units 16', 18' and 32' are assembled
together in stacked relation as seen in the views of FIGS. 2, 3 and
4, they may be secured together by means of conventional snap locks
generally indicated at 90, each snap lock 90 including cooperating
elements upon the contiguous housing units which are to be
assembled together. For example, the snap lock between the plenum
chamber housing unit 18' and the pressure chamber housing unit 32'
includes cooperating lock elements on these two housing units. Snap
locks 90 should be provided on opposite sides of the assembly as,
for example, the left-hand side and the right-hand side surfaces as
viewed in FIG. 4 of the drawings.
It should be noted that each of the housing units 16', 18' and 32'
is free standing if desired and these housing units may be used in
various arrangements as will now be described.
If the air compressor unit (including compressor 16 and the
electric drive motor 17 therefor) contained in housing unit 16' is
to be used to supply the air pressure to the system, the three
housing units 16', 18' and 32' are assembled in stacked relation as
shown in FIGS. 2, 3 and 4, and the plug-in cord 92 connected to the
electric motor 17 driving the compressor is plugged into a source
of electrical power. A suitable switch, not shown, may be provided
in the circuit of the electric motor for the compressor. With the
compressor unit operating, air pressure is supplied from the
compressor to plenum chamber 18, the air passing from chamber 18
through filter 24, regulator 26, and on-off valve 30 to pressure
chamber 32. Regulator 26 maintains the inlet air pressure to
pressure chamber 32 at the value to which regulator 26 is set by
adjustment of knob 28, regardless of any fluctuations in the air
pressure of the supply source, assuming that sufficient pressure
differential is maintained across the regulator to satisfy the
dynamic requirements of regulation, as is well known in the
art.
If it is desired instead of using the compressor unit to use the
hospital air supply 14 (FIG. 1) as a source of air for the system,
the compressor housing unit 16' and the plenum chamber housing unit
18' are detached from the assembly, and the hospital air supply 14
is directly connected to inlet fitting 25 of the filter-regulator
subassembly 24-26 from whence the air passes through filter 24,
regulator 26 and on-off valve 30 as previously described to
pressure chamber 32, the hospital air being regulated by regulator
26 to provide a constant air pressure in pressure chamber 32.
Still another manner in which the apparatus of the invention may be
employed, using an assembly of units 18' and 32', and using either
the compressor 16 as an air supply or alternatively using the
hospital air supply, is to fill plenum chamber 18 with a sufficient
amount of air to supply the necessary air pressure for a plurality
of blood transfusions as, for example, 12 transfusions of a
standard 500 milliliter blood container unit 38. With plenum
chamber 18 charged with a sufficient volume of air as just
explained, the plenum chamber housing unit 18' and the pressure
chamber housing unit 32' may be used in assembled relation with
each other as a portable subassembly, the compressor housing unit
16' being detached from and not forming part of the subassembly.
The filled plenum chamber 18 will supply air through filter 24,
regulator 26 and on-off valve 30 to inlet fitting 68 of pressure
chamber 32 in the same manner previously described. Since in this
arrangement plenum chamber 18 is filled with sufficient air for a
number of successive transfusion units, the portable assembly of
housing units 18' and 32' may be carried about the hospital and
used for transfusions as a self-contained subassembly wherever
needed, as long as sufficient stored air remains in plenum chamber
18. Each time a blood container unit is placed in the pressure
chamber the chamber must be refilled with air to the required
pressure. Also, as each container is being drained of blood, a
volume of air equal to the volume of blood removed from the
container must flow into the pressure chamber.
A still further possible manner of using the apparatus is in
conjunction with a conventional ball air pump which is manually
operated and which is directly connected by a flexible conduit to
inlet fitting 68 of pressure chamber 32. When the manually operated
ball air pump is used, the compressor housing unit 16' and the
plenum chamber housing unit 18' may be detached from the assembly
shown in FIGS. 2, 3 and 4, with only the pressure chamber housing
unit 32' being used.
When the ball air pump is used as just described, the flexible
conduit conventionally provided with the ball air pump has the end
thereof screwed onto the screw-threaded portion 69 of the inlet
fitting 68 to the pressure chamber 32 (FIG. 8), so that the air
from the ball air pump passes directly into the pressure chamber
32, and does not pass through the air filter 24, the pressure
regulator 26 and the on-off valve 30. It will be noted that fitting
68 is also provided with angular pronglike elements 71 which are
adapted to grip the flexible end of the conduit 10D used when
housing unit 32' is assembled with plenum chamber housing unit 18'
in the other assembly arrangements described.
As seen in FIG. 9, blowout seal 22 is a threaded caplike member
adapted to be received in a screw-threaded aperture in the wall of
the plenum chamber housing unit 18'. The blowout seal comprises a
blowout membrane 23 which is adapted to fracture or break at a
predetermined internal pressure in plenum chamber 18. A protective
screen 27 is provided at the outer end of blowout seal 22 to
protect membrane 23 against external damage. Blowout membrane 23
should be designed to fracture when the internal pressure in plenum
chamber 18 exceeds a predetermined value based on the design
strength of plenum chamber housing unit 18'. Blowout seal 35 of
pressure chamber 32 is similar to blowout seal 22 just described,
although the blowout membrane of seal 35 is designed to fracture at
a different pressure than the membrane of blowout seal 22.
Referring now to FIG. 7, there is shown an operational schematic
diagram of a modified forced blood transfusion system which is
connected to the hospital air supply 100. The inlet air from the
hospital air supply may have a pressure in the range of 20 to 250
p.s.i. The conduit connecting the hospital air supply 100 to the
transfusion unit generally indicated at 102 is generally indicated
at 104. Conduit 104 is provided with a male coupling which is keyed
to fit into only a standard female socket for air. This is a
standard coupling used in all operating rooms to prevent
inadvertent connection to oxygen which might lead to an explosion.
The hospital air supply 100 is electrically grounded. Conduit 104
is preferably plastic tubing impregnated with a conducting material
to pass any electrical static charges to ground. This is standard
tubing used in all operating room equipment to prevent electrical
discharges which potentially might cause an explosion. The modular
system of FIGS. 1-6 should also be grounded and all tubing thereof
should be electrically conductive to pass static charges to ground.
A metering orifice 106 is provided in conduit section 104 between
air supply 100 and pressure regulator 108. Metering orifice 106
acts in conjunction with the relief valve to be described to
prevent rupture of the rubber or elastomeric bag forming the
pressure cuff of the transfusion unit to be described, in case of
failure of pressure regulator 108. The pressure at which rupture of
the pressure cuff would occur as just described is approximately
700 mm. of mercury.
Downstream of metering orifice 106 is the air pressure regulator
generally indicated at 108 which is connected in series fluid flow
relation with conduit 104. Air pressure regulator may be of any
suitable type such as those previously described in the previous
embodiment of the invention and may, for example, be a
Fairchild-Hiller catalog 10122, Model 10 precision regulator, or a
Beckett-Harcum Regulator No. 3RO6-100-RNE. Regulator 108 is
provided with an adjusting knob 110 which may be manually adjusted
to regulate the cuff pressure of the transfusion unit within a
range of 0-425 mm. of mercury with an air flow rate of
approximately 2-20 milliliters per second. Regulator 108 should be
a "bleeding" regulator as previously described. A pressure gauge
112 is connected in conduit 104 downstream of pressure regulator
108 and should be capable of reading a pressure in the range of
0-600 mm. of mercury. A relief valve 114 is connected in the
conduit 104 downstream of pressure gauge 112 and should be designed
to operate at an appropriate value such as 500 mm. of mercury to
relieve an over pressure condition in the system in the event of
functional failure of pressure regulator 108.
A two-way valve 116 is connected in conduit 104 downstream of
relief valve 114 and has two positions. In one position of two-way
valve 116 the air flow in conduit 104 is in fluid communication
with the pressure cuff 118 of the transfusion unit, while in the
other position of two-way valve 116 the connection of the air
supply source 100 to pressure cuff 118 is closed and instead the
conduit section 104B between the two-way valve 116 and the pressure
cuff 118 is vented to atmosphere through the two-way valve, thus
venting the interior of pressure cuff 118 to atmosphere. The
two-way valve is moved to venting position, for example, when a new
blood container 122 is being positioned in the pressure cuff.
As best seen in FIGS. 7, 10 and 11, the blood transfusion unit
generally indicated at 102 includes the pressure cuff 118 which may
be a closed baglike member formed of rubber or other elastomeric
material. The pressure cuff has a hollow interior which is
connected to air supply conduit 104 by conduit section 104B. An
upwardly open pocketlike portion 120 formed of nylon netting
material or the like is suitably affixed to one of the major
surfaces of pressure cuff 118, pocket portion 120 serving as a
receptacle for the flexible blood container 122. Outlet tube 124 of
blood container 122 passes through an opening 126 provided at the
lower portion of pocket 120, tube 124 thence passing into the blood
dispensing unit 128, FIG. 7. The controlled air pressure inside
pressure cuff 118 exerts a pressure against the flexible blood
container 122 which is held in close contact with the surface of
the pressure cuff by pocket portion 120. The pressure inside
pressure cuff 118 is maintained at an adjusted constant pressure by
pressure regulator 108. The pressure exerted by the pressure cuff
on the flexible blood container 122 causes the blood to be
discharged into the patient at a constant flow rate. The pressure
at which the blood flows into the patient is nearly that indicated
by the pressure gauge 112 in FIG. 7. Since the flow and venous
pressure is low, regulating the injection pressure is equivalent to
transfusing blood at a constant flow rate.
In the system of FIG. 7, the pressure chamber 32 of the embodiments
of FIGS. 2, 3 and 4 may be substituted in place of the pressure
cuff 118 of FIG. 7, in which case the outlet end of conduit section
104B of FIG. 7 would be connected directly to inlet fitting 68 of
the pressure chamber housing unit 32'. Also, in the system of FIG.
7, a compressor could be substituted for the hospital air supply as
the source of air for the system. However, since no plenum chamber
is used in the system schematically shown in FIG. 7, a compressor
of larger flow rate capacity is required than would be required if
a plenum chamber were being used.
It can be seen that in accordance with the invention there is
provided a system and apparatus for providing intravenous or
intra-arterial injections such as blood transfusions or the like in
which the injection may be made under a controlled air or gas
pressure which can be preset and which is maintained at a constant
predetermined desired value regardless of fluctuations in the
source pressure by an air pressure regulator in the system, the
controlled air pressure forcing the liquid such as blood from the
dispensing unit into the patient at a constant rate. Furthermore,
there is provided in accordance with the invention an integrated
system of modular components which permit a great degree of
flexibility in their arrangement and operation. Thus, using the
pressure chamber alone, the system can be operated manually with a
ball air pump or can be operated by the regulating system of FIGS.
1 and 7. The pressure chamber portion of the apparatus used alone
can also be used as a gravity feed device for the blood or the like
being injected. When the pressure chamber 32 is used in conjunction
with the regulator it can be operated either using the plenum
chamber 18 supplied by the compressor or it can be operated
directly on hospital air subject to regulation by the regulating
device and without the plenum chamber.
Still a further arrangement in accordance with which the apparatus
may be used is that the plenum chamber may be charged up with air
by either the compressor or by the hospital air supply to a
pressure and volume sufficient for a predetermined number of
transfusions, such as twelve 500-milliliter transfusions. With the
air thus stored in the plenum chamber, the assembly of the pressure
chamber and the plenum chamber may be used as a portable assembly
and taken wherever required for use in making intravenous
injections such as blood transfusions.
A compressor of low flow rate capability can be used with the
plenum for use in administering intravenous or intra-arterial
injections assuming the plenum is initially charged with air. In
this case, the compressor only has to furnish air as the blood is
displaced from the blood container and to recharge the pressure
chamber after it has been opened to remove and replace a blood
unit.
From the foregoing detailed description of the present invention,
it has been shown how the objects of the invention have been
obtained in a preferred manner. However, modifications and
equivalents of the disclosed concepts such as readily occur to
those skilled in the art are intended to be included within the
scope of this invention.
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