Note: Descriptions are shown in the official language in which they were submitted.
Cross Reference to 'Related Appl-lcations
(None)
Background of the Invention
This invention relates to an apparatus which can
controllably administer a parenteral liquid. Uore particularly,
this invention relates to an intravenous administration set
which will revert to a different or keep-vein-open ~KV0) flow
rate when the solution in a container empties.
In the administration of parenteral liquids, the
source of parenteral liquid will eYentually be exhausted.
Unless a constant surveillance i6 made during the administration,
in many instances the source of liquid will become depleted
to the patient with the needle in communication with the
vein. When this occ~rs, blood can coagulate around the
needle thus effecting a blockage of the end of the needle or
the si-tus where the needle enters the vein. In order to then
effect flow when a new solution container is attached, the
needle would have to be withdrawn and reinserted a't a new site.
A unit which is provided to obviate the foregoing adverse
20' effects and t~ a~ford a dLfferent flow' rate in a parenteral
liquld i9 descri'bed 'by Pric'e in U.S'. 3~738?361. However,
thls particular unit re(luires preclse positionlng of ~o~ing
parts which is costly to manufacture and can cause p~oblems
during usage. Another device which proyides a XyO rate is
described in applicant's U.S. patent no. 4,173~222 issued
November 6, 197~ This particular device utilizes two
spaced orifices and some problems have arisen concerning
this device in that an abrupt change in flow rate occurs
when the top filter or membrane shuts off and the lower smaller
area membrane assumes the eneire liquid flow duri-ng the KV0
period.
X - 1 -
c g t ~( ~
-2-
It is an advantage of the present invention
to provide a novel administration apparatus for a par-
enteral liquid which has a keep-vein-open means. Other
advantages are an apparatus for administering I.V.
liquids which affords two different flow rates with
means which are easy to fabricate and afford positive
and reliable functions; an I.V. administration unit
which not only can afford different flow rates but can
do so without utilizing moving parts; an apparatus
which can accomplish a keep-vein-open effect without
moving parts and which affords an a~ded advantage of
filtering out particulate matter as well as air or
gases; a device which in certain embodiments will re-
tain a level of I.V. liquid in the sight chamber and
tubing even when the KVO reservoir empties thus avoid-
ing a new venipuncture; and a device which can smoothly
convert from a regular to a KVO flow rate.
Summary of the Invention
The foregoing advantages are accomplished and
the shortcomings of the prior art overcome by the present
apparatus which is comprised of a reservoir chamber hav-
ing opposing first and second end walls. Connection means
for a parenteral liquid container define a fluid 10w in-
let passageway into the chamber through the fir~t end wall.
A fluid flow outlet passageway is in fluid-tight engagement
with the second end wall of the chamber. Fluid passage
means extend into the chamber in the direction of the
first end wall presenting portions proximal and remote
therefrom. The fluid passage means is in communicatio~
A 30 with the fluid flow inlet and outlet passag~way. ~ ~n ~t
means in the form of an orifice is provided in the fluid
passage means with means operatively associated with the
orifice to provide a faster flow rate of parenteral liquid
through portions proximate the first end wall of the cham-
ber than portion~ remote therefrom and to substantiallyeliminate the flow of air into the orifice. The usual
means for administering the liquid to the patient is con-
nected to the fluid flow outlet passageway.
--3--
In a preferred embodiment, the means for af-
fording a faster flow rate through portions o the inlet
means proximate the first end wall of the reservoir cham
ber and to substantially eliminate the flow of air into
the orifice is an orifice having a T-shaped configuration
with the head of the T-shaped portion extending over an
end wall of the fluld passage means as well as perpendicu-
larly over the side wall thereof.
Brief Descri~tion_of_the Drawi~
A better understanding of the apparatus for
admlnistering a parenteral liquid according to this in-
vention will be accomplished by reference to the drawings
wherein:
FIGURE 1 is a view in side elevation showing
the apparatus of this invention operatively connected to
an I.V. solution bag and having interconnected thereto
the usual tubing with a hypodermic needle and flow control
clamp.
FIGURE 2 is a view in vertical section of the
apparatus of this invention showing the reservoir filled
to an operative level with liquid and the orifice dis-
posed between the end walls of the reservoir chamber
and placed on a bias with respect thereto and a drip
chamber integrally secured at the bottom of the reservolr.
FIGURE 3 is a partial detailed view in perspec~
tive of the orifice and fluid passage rneans shown in
FIGURE 2 with the filter member removed therefrom.
FIGURES 4, 5, 6 and 7 are views similar to
~IGURE 4 illustrating additional embodiments of orifice
configurations and filters for the fluid passage means.
Description of One_Embodiment
Proceeding to a detailed description of one
embodiment of the present invention, the controlled I.V.
administration apparatus 10 is shown in FIGURE 1 in con-
junction with a conventional parenteral solution bag 11
which is described in U. S. Patent 3,915,212. A standard
drip or sight chamber 12 is secured to the opposite end
of the I.V. administration apparatus and a length of
tubing 14 extends from the drip chamber which is ulti-
mately connected to a hypodermic needle assembly 15 with
the control of fluid in the tubing being effected by
means of an adjustable flow control clamp 17.
As best seen in FIGURE 2, the controlled I.V.
administration apparatus 10 is composed of a reservoir
chamber 20 having a deformable cylindrical side wall 21.
Enclosing one end of the chamber is a piercing pin as-
sembly 22 having a pointed end portion 18. A ~luid flow
inlet passageway 23 extends through the piercing pin
assembly to permit I.V. liquid to flow into chamber 20.
At the opposite end of chamber 20, is a closure 25 having
an end wall 28, a reduced diameter section 27 for accom-
modating wall 21 and also a centrally disposed drip
forming member 26. Extending into the reservoir chamber
20 and in fluid communication with drip forming member
26 is fluid passage means 30 in the form of a tubular
member 32 having at one end a unitary orifice 33 covered
by a filter membrane 31. It will be noted that orifice
33 has a longitudinal axis which extends between end
walls 19 and 28 and on a bias or slant with respect
thereto.
Réferring specifically to FIGURE 3 it will
be noted that orifice 33 includes a reduced inner annular
section 46 for seating of the filter 31 and securing it
thereto such as by means of heat sealing. Alternatively,
ultrasonic or epoxy seaLing could be used. Preferably,
filter 31 i5 formed from a cellulose acetate material
such as produced by the Millipore Filter Corporation lo-
cated at Bedford, Massachusetts. The filter material is
of the hydrophilic type. In the instance of filter 31,
it is of .8 micron size and elliptical in configuration.
Extending from closure 25 and secured thereto
by means of annular flange 38, is a standard cylindrical
drip chamber 12 which has secured at the opposing end
a length of flexible plastic tubing 14 for delivery of
I.V. liquid 16.
s
Description of Other Embodlments
In the following FIGURES 4 - 7, other embodi-
ments of the previously described controlled I.V. admin-
istration apparatus 10 are described.
In the embodiment 50 shown in FIGURE 4, the
fluid passage means 56 is ln the form of a hollow tubular
member 54 having a closed end wall 52. Positioned ln
the side wall 55 and in a circumferentlal manner is an
orifice 53 of a generally elliptical conflguration.
Covering orifice 53 is a membrane or filter 51 which is
of the same configuration as orifice 53 and sealed to the
side wall 55 surrounding the oriflce in the manner ind,i-
cated for or,ifice 33.
The embodiments 60 and 70 shown ,in FIGURES 5
and 6 are similar to the embodiment 50 of FIGURE 4. Con-
cerning unit 60 it will be seen that membrane 61 is of
a tear drop configuration as is orifice 63 in side wall
65. The hollow tubular member 64 provides a fluid passage
means 66 through reservoir end wall 28 and ls closed by
end wall 62 at the opposite end. Un:it 70, which is a
preferred embodiment, has a generally T-shaped orifice 73
covered by a corresponding T-shaped membrane 71. The T-
shaped orifice has portions extending over both the end
wall 72 and side wall 75 of hollow tubular member 74 with
membrane 71 sealed to both the end and s,ide wall. End
wall 72 otherwi.se c'loses tuhular member 7~ to provide a
fluid passage means 76 through orifice 73.
In the embodiment 80 descr,~bed in FIGURE 7 the
single channel orifice 83 and membrane filter 81 is
rectangular in configuration. In place of the hollow
tubular members forming the fluid passage means in units
50, 60 and 70, a hollow box-like member 84 provides a
fluid passage means 88 and is disposed in fluid commu-
nication through reservoir end wall 28 at one end, being
closed such as at 82 at the opposite end. Filter 81 is
composed of varying bands of mesh sizes w,ith a coarse mesh
band 85 at the top, a fine mesh band 87 at the bottom and
an intermediate mesh band 86 in between.
-6-
Operation
A bet-ter understanding of the advantages of
the controlled I.V. administration apparatus 10 as well
as those described ln the other embodiments will be had
by description of their operation. As all of the units
operate on basically the same principle, only the embodi-
ment referred to as unit l0 will be described with
specific comments made for the other embodiments in any
manner in which they may differ in their operation.
The controlled I.V. administration apparatus
10 will be packaged separately from a solution container
11. When it ls desired to administer the contents of
an I.V. liquid 16, such as contained in an I.V. bag 11,
the piercing pin 18 will be inserted through the admini-
stration port unit 19 to provide fluid communication be-
tween the inside of bag 11 and reservoir cha~ber 20. At
this point9 the unit 10 will be assembled as shown in
FIGURE 1 with bag ll suitably supported in a vertical
position. The reservoir chamber 20 will be primed by
squeezing together the flexible side wall 21 as required
to fill it so that the fluid passage means 30 and mem-
brane 31 are submerged and the chamber filled to a level
29 of liquid 16 as shown in FIGURE 2. The drip chamber 12
wlll next be primed by squeezing lt wall to wall and
held in a squeezed position until the tublng clamp 15 is
closed. The force ls then released on the drip chamber
12 which actlon will draw solution through the membrane
31 and prime the drip chamber The foregoing action can
be repeated as needed to fill the drip ~hamber 12 half
full as indicated in FIGURE 2.
After the foregoing priming action, the needle
assembly lS is attached and the air in tubing 14 is ex-
pelled by opening the clamp and allowing the set to run.
The appropriate venipuncture is made by needle 41 and
the set which includes all of the foregoing mentloned
components in conjunction with the controlled I.V. admin-
istered apparatus 10 is then ready for I.V. administra-
tion. Fluid 16 flow rate is established by adjusting
--7--
the flow clamp 17 until the desired rate of administra-
tion .i5 obtained. Liquid will flow through orifice 33
and f.ilter member 31 and will continue to be admin~
istered at a glven predetermined rate determined by
clamp 17 until the solution container empt.ies. When this
occurs, the fluid level in the reservoir 20 will drop be-
low the upper level of orifice 33 and membrane 31 as indi-
cated by reference numeral 90. At this point, the con-
trolled I.V. administrat.ion apparatus 10 will slowly re-
vert to a keep-vein-open rate which will be a slower one
than that accomplished in utilizing both the entire sur-
face area of orifice 33 and membrane 31. Once the level
is below the upper level 90, the liquid will flow only
through the portion of membrane contacted by the lowering
liquid level. It will be apparent that as the l.iquid
level is lowered less liquid will flow through membrane
31. However, as membrane 31 and orifice 33 are placed in
an oblique manner with respect to the longitudinal axis of
tubular fluid passage means 30, it will take considerable
time before the liquid level travels the distance indicated
by arrow 34 and reaches the lowermost portlon of orifice
33. This will become even more apparent w~en considering
that flow rates of I.V. solutions range from 5 to 20Q ml.
per hour with a typical flow rate be.ing 125 ml./hr. The
preferred time for liquid to travel the indicated distance
would be 1 hour. This slower rate is established so that
a constant flow is permitted through drip chamber 12, tub-
ing 14 and into the vein so as to keep a flow maintalned
until a new solution container or bag 11 can be utilized.
In the event a new solution container is not intercon-
nected to set 10 before all liquid empties from chamber
20, a level of liquid will be maintained in sight chamber
12 as filter 31 will afford an air lock. A new venipunc-
ture will not be required because of the hydrostatic pres-
sure. All that is required is to connect a new solutioncontainer 11 and reprime reservoir 20 as previously indi-
cated.
The length of time that the KVO rate is de-
livered after the container 11 empt.ies is dependent on
the volume of solution .in the reservoir chamber 20 and
the rate of flow that the membrane 31 allows liquid to
pass.
The KVO rate is independent of the flow rate
set by clamp 15 prov.ided the flow clamp is adjusted to
a faster rate than the KVO rate~ Because of the porosity
and hydrophilicity of membrane 31, it will not pass air
when the reservoir 20 empties.
The operation of embodiments 50, 60, 70 and 80
will be the same as previously indicated for unit 10
except that the flow through the orifices 53, 63, 73
and 83 as well as the respective filters 51, 61, 71 and
81 may be different from a time standpoint~ This is
due to the volume of liquid in chamber 20 and the fact
that either greater or lesser surface area is contacted
by fluid 16 as its level drops in the chamber, when com-
pared to orifice 33 and filter 31. It should be further
noted that orifices 53, 63, 73 and 83 are all disposed
in a parallel manner with respect to the longitudinal
axis of the hollow tubular members 54, 64, 74 and hollow
box member 84, except that in the instance of orifice
73 it also has a portion which extends over the end
wall of tubular member 74. When compared to the biased
orifice 33, the total time for the l.iquid level to drop
below the lowest level of the orif.ice as indicated by
numeral 9l will be faster for the same size and configur-
ation of orifice.
Concerning embodiment 80, membrane 81 offers
an additional advantage in having the filter of different
mesh size with the degree of coarseness offering more
resistance in stages as the liquid level drops. Thls
would afford a slower total flow rate until the level
reaches the bottom of orifice 92.
It will be appreciated in all of the units,
that the only pathway for the llquid from chamber 20
is through one of the orifices 33, 53, 63, 73 or 83
8~
g
into hollow fluld passaye means 30, 56, 66, 76 and 88,
and ~hrough end wall 28 by means of hollow drlp forming
member 26. Once the liquid level drops below the lower
portion of the or,iice such as shown at 91 and 92 no
more liquid will flow through tubing 14.
It w,ill be obvious that orifices 53, 63, 73
and 83 need not be disposed in a parallel manner with
respect to fluid flow or 90 degrees with respect to
end walls 19 and 28. They could be placed in a slanted
or biased manner as indicated for orifice 33. The angle
degree for the orifices can vary from O (parallel to the
housing axis) to any angle less than 90 degrees.
In the foregoing description the inlet means
has been described as a single continuous orifice. If
desired, the inlet or orifice means could be in the
form of a series of contlnuous apertures with the fil-
ter membrane placed thereover. In this manner the wall
portions surrounding the apertures would serve as back-
ing support for the filter.
A distinct advantage of the single inlet means
for the purpose of effecting a prolonged flow rate is that
an abrupt change in flow rate is not brought about with
an interruption of 10w as the liquld level drops across
the orifice. This abrupt change has been noted ln those
units for effecting a KVO rate when employlng two separate
oriices. By employing a single orifice the transition
from a faster ~o a slower rate is more gradually effected.
Another advantage of the present units is the use of a
filter membrane which can be hydrophilic to prevent the
passage of air into the 1uid passage means and the tub,ing
14.
The foregoing described units are all dispos-
able with the reservoir chamber formed from a clear flex-
ible plastic cellulose propionate material. The cylin
drical walls are solvent sealed to the piercing pin
assemblies as well as to the end closures. The same
technique is employed in securing the drip chamber to
the annular flanges in the outlet closure, The filters
--10--
are secured to the fluld passage means by a heat seal
wlth the fluld passage means or hollow housing being
of a rigid ABS (acrylonitrlle/butadiene/styrene) material.
Obviously, other plastic materials could be employed
which are inert to I.V. liquids and in the instance of
the side wall ~1 it could be composed of glass although
this would pose a slightly more difficult problem in
priming the system. While cellulose acetate is the
preferred ma-terial for composing the filters, other
filtering materials of the cellulose family or deriva-
tives of the cellulose family such as cellulose nitrate,
cellulose triacetate, mixed esters of cellulose or regen-
erated cellulose could be employed with the provision
that they be hydrophilic with a maximum pore size of
less than 10 micrometers. Filters made from vinyls,
copolymers of vinyls and polycarbonate could also be used.
It will thus be seen that through the present
invention there is provided a controlled I.V. administra-
tion apparatus which is simple in its construction yet
will allow for a gradually reduced but continuous flow
rate of fluid automatically after a fluid level drops
below a predetermined level. Except for vertical place-
ment, no special orientation is required. The membranes-
offer added advantages in that a filtering o any particu~
~5 late material is effected, the elimination of any 10w
oE gas into the system and ~limination of a new veni-
puncture even when the liquid in the reservoir chamber
is completely exhausted. The administration apparatus
of this invention can be composed of inexpensive materials
and thus is disposable. Automatic reversion from a faster
flow rate to a slower flow rate is accomplished without
supervision of the units, a source of external power or
an interruption of flowO
The foregoing invention can now be practiced by
those skilled in the art. Such skilled persons will know
that the invention is not necessarily restricted to the
particular embodiments presented herein. The scope of the
invention is to be defined by the terms of the following
claims as given meaning by the preceding description.
