Apparatus for controlled liquid administration

A control apparatus for a parenteral administration set which includes a calibrated rate control clamp for determining the time period over which the contents of a standard supply container of physiological liquid is delivered. The clamp selectively constricts the tubing interconnecting the supply container with a patient and the constriction is correlated with a calibrated scale. A spring device is provided to assure that the constriction is removed responsive to loosening of the clamp. This provides for an easy and rapid setting of a given time period over which the known volume of the liquid in the supply container is infused into the patient.

This invention relates to an apparatus for regulating the administration of 
fluids, and more particularly, relates to an improved rate control 
apparatus in which the rate of flow is correlated with a calibrated scale. 
Parenteral solutions such as intravenous feeding solutions are normally 
transferred from a container to a patient by means of parenteral 
administration sets. The transfer of the physiological liquid from the 
container and subsequent infusion into the patient is achieved by 
suspending the container; e.g., a glass or plastic bottle or flexible bag, 
above the patient. The insertion means of the parenteral administration 
set, which is inserted into the supply container of liquid, is connected 
in series with a drip chamber, tubing and a means for attaching a needle. 
In the prior art, roller clamps for controlling the flow rate of liquid are 
attached to the tubing. After appropriate steps to remove trapped air from 
the administration set and establish a drip rate, the needle is inserted 
into the patient. 
One major disadvantage of the aforementioned administration sets are the 
roller clamps which are attached to the tubing in order to control the 
drip rate. The roller clamps comprise an inclined plane, a circular roller 
containing ridges and means for guiding the roller and tubing. The tubing 
is positioned between the inclined plane and the roller. By adjusting the 
position of the roller along the inclined plane, the tubing is compressed 
thereby reducing the rate of flow of liquid through the constriction. In 
order to achieve a given drip rate, the operator must selectively move the 
roller and determine the drip rate by counting the drips, mentally convert 
the drops into milliliters, adjust the position of the roller, and repeat 
the above sequence until the desired drip rate is achieved. 
This means of controlling the drip rate is both cumbersome and further, 
suffers from the disadvantage that the roller clamp can slip during the 
infusion process thereby altering the drip rate. The consequences of such 
a slippage can be very serious, particularly, if medication is being 
administered to the patient. The drip rate must, therefore, be 
periodically monitored and adjusted, if necessary. 
Various solutions for measuring both the rate and volume of delivery have 
been proposed. U.S. Pat. No. 3,776,229 discloses an apparatus for 
measuring these quantities. A valve structure is employed which permits 
the determination of the rate and volume of delivery. The actual drip rate 
of the fluid infused into the patient is, however, controlled by a 
conventional roller clamp which requires counting of changes to establish 
a given drip rate. 
Other liquid administration sets for delivering a predetermined volume of 
liquid are described in U.S. Pat. Nos. 3,774,603; 3,844,283 and 3,625,211. 
These administration sets also employ a conventional clamp for controlling 
the flow rate. They further require secondary chambers and valve means. 
A problem encountered when using constriction means for constricting the 
tube to control the fluid flow rate is that the plastic tube as a "memory" 
and therefore remains constricted, even after removal of the constriction 
means. Hence, it is difficult and often impossible to effectively go from 
a slow rate to a faster rate. 
If very accurate and constant drip rates are desired, U.S. Pat. No. 
3,931,818 discloses a sump interconnected to a flow controlling float 
chamber by means of a double bore metering tube. It is also possible to 
regulate the drip rate electronically as disclosed in U.S. Pat. No. 
3,871,229. The constriction means for controlling the rate of flow as 
described in this patent is a threaded shaft which constricts a tube 
carrying the fluid. While the drip rate can be controlled manually, the 
sensing of the drip rate is electronic and thus the rate of flow, as 
measured by the drops per minute scale, is determined electronically. 
These complicated means for controlling the drip rate are economically 
impractical for use in the usual parenteral administration set, since such 
sets are designed for one-time use and are disposable. 
The present invention relates to a parenteral administration set for 
infusing clear liquids, such as a glucose feeding solution, from a supply 
container into a patient. An important feature of the administration set 
relates to a clamp for restricting the flow of liquid through flexible 
tubing which connects a supply container to a patient. The clamp includes 
a threaded shaft by which means the constriction on the tubing can be 
varied and a calibrated scale which cooperates with the threaded shaft, 
whereby an operator can quickly set the clamp for a predetermined time 
period and drip rate in which the contents of a supply container can be 
infused into the patient. 
A substantial majority of intravenous feedings involve five (5%) percent by 
weight glucose solutions in a 1000 ml container. The clamp, in a preferred 
embodiment is, therefore, calibrated against such a solution suspended at 
a standard height of five feet. By using the time scale on the clamp, an 
operator can quickly select the time period over which the contents of the 
1000 ml container are delivered. Alternatively, the drip rate scale may be 
used to select a predetermined drip rate and the amount of liquid 
delivered over any given period can be quickly calculated. 
It is therefore, an object of the present invention to provide calibrated 
apparatus for delivering the contents of containers holding fluid for 
intravenous injection. 
Another object of the present invention is to provide calibrated apparatus 
for quickly and accurately setting a given time period over which the 
contents of a standard supply container will be delivered. 
A related object of the present invention is to provide calibrated clamps 
for selectively constricting the tubing used in delivering the intravenous 
fluid. 
Still another object of the present invention is to provide resilient means 
for assuring that the constriction of the tubing is removed and the clamp 
is loosened. 
Another object of this invention is to provide calibrated apparatus for 
quickly and accurately setting given drip rates. 
Another object is to provide simply drip rate controlling apparatus which 
can be economically manufactured for use in disposable parenteral 
administration sets.

FIG. 1 discloses an administration set for infusing a clear intravenous 
feeding solution into a patient. A supply container, which may be the 
bottle 11 shown in FIG. 1 or the plastic container 11 shown in FIG. 6, is 
suspended from a headstand which comprises a base 19, supporting column 18 
and hook 17 attached to said headstand at a standard height of five feet. 
The administration set includes flexible tubing 16 attached to a flexible 
drip chamber 15. The drip chamber contains an infiltration indicator 14 
and is connected to a drop cannula 13 and an insertion spike 12. The 
flexible tubing 16 is shown containing a coil 20, an insertion site 21, 
and is attached to a latex sleeve 22 which contains a rigid needle adapter 
23. Attached to the tubing is a clamp or pinch valve 24 for controlling 
the flow of liquid through the tubing. The coil 20 is resilient and 
resumes the coiled shape after being stretched, similar to the familiar 
coiled telephone cords. 
Having described the basic components of the parenteral administration set, 
the details of the clamp or pinch valve 24 will be discussed. As shown in 
FIG. 2, the clamp comprises a solid base structure or body 25 which is 
preferably made of a molded plastic material. In the lower portion of the 
base structure is a hole or through opening or passage 28 which traverses 
the length of the base, the hole 28 being of sufficient diameter to 
accommodate the flexible tubing 16 in slidable close fitting relation. A 
threaded rotatable shaft 26, having a rounded end 29, extends through 
threaded hole 27 from the top of the base structure to the lower portion 
containing the tubing 16. The rounded end 29 passes through an opening 30 
which enables contact of the shaft 26 with the tubing 16 so that it can be 
pinched against the portion of body 25 opposing shaft 26, on the opposite 
side of passage 28, which body portion serves as the valve seat. 
Mounted on the shaft 26 are a knurled indicator knob 31 and a calibrated 
scale plate 32. The pitch of the threads 27 is such that one full 
revolution of shaft 26 will cause movement of the shaft 26 in an upward or 
downward direction by approximately the diameter of the tubing 16. The 
upward or downward movement of the shaft 26 per increment of rotation of 
knob 31 is a function of the pitch of threaded shaft 26. 
In FIG. 3 the clamp 24A is shown as comprising a solid body 25A having a 
hole 28 traversing the length of its base. The flexible tubing 16 is 
accommodated in hole 28. Rotating indicator knob 31 causes rotation of 
threaded shaft 26 which in turn moves hammer 41 which is threadably 
coupled to the shaft 26 to move in hole 42 in the body 25A. The hammer 41 
presses the tubing 16 against anvil 43, that serves as the valve seat in 
the embodiments to constrict the tubing 16 a controlled amount. 
The scale side view of the clamp is shown in FIG. 4. The calibrated scale 
plate 32 is attached to shaft 26. A pointer 35 is attached to the base of 
knurled knob 31. The scale 34 of scale plate 32 is calibrated in hours 
required to deliver the contents of a 1000 ml supply container hung at a 
height of five feet and containing, for example a five (5%) percent 
glucose solution. The corresponding drip rate in drops per minute for the 
respective time periods is shown on scale 33 formed on body 25A. 
To explain how the administration set is operated, reference is made to the 
Figures. The pointer 35 of the indicator knob 31 is rotated to the "off" 
position, as shown on scale 33. In the "off" position, the tubing 16 is 
completely closed due to pressure exerted by shaft end 29 or hammer 41. 
The protective disc is removed from supply container 11 and the protective 
cap is removed from the insert spike 12. The flexible drip chamber 15 is 
squeezed, and the insertion spike 12 then is hung from hook 17 at a height 
of five feet. The drip chamber is then filled to the infiltration 
indicator mark 14 by alternately squeezing and releasing the drip chamber. 
In order to clear the tubing of air, the indicator knob 31 is rotated to 
an "on" position and the tubing completely filled with liquid. 
At this point, the operator can select a point on the hourly scale 34. The 
indicator knob 31 is simply rotated until the desired hourly setting is 
indicated by the "off" marker of scale 33. This corresponds to the number 
of hours required to deliver, for example, 1000 ml of five (5%) percent 
glucose solution contained in the supply container. If a 500 ml container 
is employed, the hourly scale 34 will be divided by a factor of 2. 
Alternatively, the operator may use the drip rate scale 33, which is 
calibrated in drops per minute, and moving knob 31 to set pointer 35 at 
the desired drip rate of scale 33. The rate of discharge of solution from 
the drip chamber 15 is controlled by the pressure on tubing 16 which is 
created by movable shaft 26 of clamp 24. Of course, the rate of discharge 
of solution from the drip chamber also controls the drip rate from the 
drop cannula 13. Any given drive rate may be selected from the calibrated 
drip rate scale 33 and the volume delivered over any given time period 
quickly calculated. 
Another preferred embodiment 24B of the clamp 24 is shown in FIGS. 6-8. 
Therein means are provided for assuring that the constricted tube 16 
follows the shaft of the clamping device as the indicator knob is rotated 
from the "off" to the "on" position. 
More particularly, as shown in FIGS. 6-8, resilient means such as spring 
arms 51 and 52 of shaped spring 53 normally apply pressure to opposite 
sides of tubing 16. The pressure is applied in the quadrants removed 90 
degrees from the point of pressure application applied by the screw shaft 
26. 
The embodiment of the clamp means 24B shown in FIGS. 6, 7 and 8 is 
comprised of a body 25B in the form of a bottom disk 54 spaced apart from 
a top disk 56 by a center cylindrical section 57. Preferably, the top and 
bottom disks are joined together using well known adhesives. The disks 54 
and 56 and cylindrical section 57 are constructed of a suitable plastic, 
such as plexiglass or Bakelite. 
Means, such as apertured tabs or panels 58 and 59, are provided for 
positioning and retaining the tube 16 aligned with the shaft 26. A pair of 
oppositely disposed apertures 61 and 62 are provided in center section 57 
to enable the tube 16 to pass through clamp 24B. The apertures of panels 
58 and 59 form, with apertures 61 and 62 of section 57, the through 
opening or passage through which tube 16 is to extend through body 25B. A 
threaded stabilizing section 63 is provided underneath centrally located 
threaded hole 64 in a top disk 56 to stabilize shaft 26 of clamp 24B. The 
spring 53, as best seen in FIG. 6, may be characterized as a C-shaped 
clamp spring. The arms 51 and 52 are themselves shaped to fit around screw 
shaft 26 and nonetheless apply pressure to the sides of tubing 16 on both 
sides of the shaft 26, independent of the degree of clamping of shaft 26 
against tubing 16. The base 64 of the C-shaped clamp spring 53 has a 
protuberance portion 66 rising from the arms thereof at the center of the 
ring shaped portion 66. A passage aperture 67 is provided through spring 
base 64 to enable the passage therethrough of tubing 16. 
Since the present invention is subject to many changes and modifications in 
detail, all matter described hereinbefore or shown in the accompanying 
drawings is to be interpreted as illustrative and not as limiting.