Medical Liquid Administration Set For Rate Or Volume Delivery

Abstract

A parenteral liquid administration set which is readily changeable between delivering liquid at measured "rate" through a drip chamber that has a constant liquid level, and delivering liquid from the chamber in a measured "volume" with a progressively lowering liquid level. A valve system on a top of an enlarged semi-rigid measuring chamber functions to selectively change between "rate" and "volume" delivery. In one version there is also a secondary drip chamber below the enlarged semi-rigid measuring chamber so the set can simultaneously indicate "rate" and "volume" delivery.

Description

BACKGROUND

Parenteral liquids such as intravenous solution or blood are generally dispensed to a patient through an "administration set." The adminstration set includes a long flexible tube connected at its upper end to an inverted liquid supply bottle and connected at its bottom end to a patient. An enlarged drip chamber is joined in series with the tubing between its ends. A nurse or physician can determine how fast the parenteral liquid is being administered by counting the drops falling into the drip chamber over a given period of time. The rate of liquid administration in ml/hr. is then calculated from the drip rate by a known conversion factor.

The problem with drip chambers of this type is that they do not provide an easy manner of measuring both "rate" and "volume" delivery. First the nurse or physician has to count the number of drops per minute and convert them into ml/hr. for the "rate." Then if a specific "volume" is to be administered at this rate a further calculation is needed to determine how long the administration should be continued to deliver this volume. For instance, if a physician told a nurse to administer 40 ml. of liquid at 25 ml/hr. this becomes quite a tedious mathematical problem. This is particularly burdensome where a nurse might monitor several different parenteral liquid administrations simultaneously. Calibrations on the large liquid supply bottle, one or two liter capacity, are not accurate enough for measuring volumes of less than 100 ml.

SUMMARY OF THE INVENTION

I have overcome the above problems with the parenteral liquid administration set by providing an administration set which can be conveniently changed by a nurse or physician to indicate a "rate" or "volume" delivered. The rate is measured by a constant liquid level drip chamber and the volume is measured by a descending liquid level within an enlarged semi-rigid chamber. This chamber has approximately 100 ml. capacity and is volumetrically calibrated.

An important feature of my invention is a unique valving structure at a top portion of the enlarged chamber. When the valving structure is closed the chamber forms an airtight drip housing where liquid is received and dispensed while liquid in the chamber remains at an approximately constant level. When the valving structure is opened to the atmosphere, the chamber is filled to a given volumetric level and liquid dispensed from the chamber in a progressively lowering liquid level gives an instant reading of volume dispensed. As this level reaches a lower portion of the chamber an automatic float valve closes the chamber's outlet passage to prevent air from being administered to the patient.

In one version of my invention a secondary drip chamber is attached to an outlet of the enlarged chamber. Thus, as liquid drains from the enlarged chamber in a volumetrically measured administration the secondary drip chamber will give a simultaneous rate reading in the number of drops falling into the secondary chamber.

With my invention a nurse or physician can get a quick and easy reading of the "rate" liquid is being administered, and also obtain a convenient accurate reading of how much "volume" has been dispensed.

THE DRAWINGS

FIG. 1 is a side elevational view showing the administration set measuring the "rate" of liquid dispensed;

FIG. 2 is a side elevational view similar to FIG. 1, but showing the "volume" dispensed;

FIG. 3 is an enlarged sectional view of a top cap of the enlarged chamber, showing an upstanding rigid tube portion of the valve structure;

FIG. 4 is an enlarged sectional view of a rotatable cap member fitting over the rigid tube of the cap and combining with it to form the valve;

FIG. 5 is a bottom view of the cap of FIG. 4;

FIG. 6 is a sectional view taken along 6--6 of FIG. 4;

FIG. 7 is a fragmentary top view taken along line 7--7 of FIG. 3; and

FIG. 8 is an exploded perspective view of the top portion of the enlarged housing with its rigid upstanding tube, and the valve cap.

DETAILED DESCRIPTION

The parenteral liquid administration set of my invention includes a conduit 1 that has a spike 2 at its upper end connected to a liquid supply bottle 3. This bottle may contain blood, intravenous solution, etc. A lower end of the conduit 1 is attached to a conventional intravenous needle (not shown).

Joined in series with this conduit 1 is an enlarged chamber 4 shown in the drawings as being of approximately 100 ml. capacity. This could also be of 150 ml. capacity if desired. The enlarged chamber is comprised of a cylindrical transparent wall 5 with volumetrically calibrated indicia 6. Connected to this cylindrical wall are a top cap 7 and a bottom cap 8 which have an inlet passage 9 and an outlet passage 10 respectively. To control liquid flow rates to and from the enlarged chamber are conventional roller clamps 11 and 12 on the conduit 1.

In FIG. 1 there is shown a secondary smaller drip chamber 13 connected to bottom cap 8. This secondary drip chamber will be explained in more detail later and how it is used with the enlarged chamber 4 to simultaneously measure "rate" and "volume" delivery. However, the enlarged chamber 4 can be used to measure both "rate" and "volume" delivery by manually changing a valve on top cap 7. In this later instance there is no secondar drip chamber and conduit 1 connects directly to outlet 10 of the enlarged chamber 4.

Having discussed the basic components of the administration set, the details of the enlarged chamber 4 and particularly its top cap 7 will be described. As shown in FIG. 1 the administration set is delivering a constant measurable rate of liquid. This rate is determined by counting the number of drops 14 falling across an air pocket 15 directly above a liquid level 16. In FIG. 1, where the "rate" delivery is shown, the roller clamp 11 is open so liquid can drain from bottle 3 into chamber 4. A valve means on the top cap shown generally as 17, is in an airtight closed position. This creates an airtight enlarged chamber 4 which functions as a drip housing and a liquid level 16 remains at a generally constant height within the chamber.

When it is desired to administer a precise quantity of parenteral liquid, the administration set is changed to that shown in FIG. 2. In FIG. 2 roller clamp 11 closes off conduit 1 and valve member 17 is opened to the atmosphere. This causes the liquid level 16 shown in FIG. 2 as initially being at 65 ml. to drop to the level shown in solid line, i.e., 45 ml. Any amount of liquid up to the enlarged chamber's capacity can be supplied to it merely by opening roller clamp 11. In both the FIG. 1 and FIG. 2 showing settings the flow rate to the patient is controlled by roller clamp 12.

In practice, a nurse or physician can begin a liquid administration as shown in FIG. 1 at perhaps 300 ml/hr. If the physician gives an instruction to administer 65 more ml. at this rate and then stop the administration the nurse needs merely to open valve 17 and fill the enlarged chamber 4 to 65 ml. Next, roller clamp 11 is closed off. As the liquid within the chamber 4 is dispensed at the constant 300 ml/hr. (controlled by roller clamp 12) the liquid level 16 will gradually descend within the enlarged chamber 4. This liquid level descent continues until a floating disc valve 20 within cage 21 contacts valve seat 22 to close off further passage of liquid or air through outlet 9 of the bottom cap. As can be seen, this is a very simple procedure and the nurse does not need to calculate how many minutes a 300 ml/hr. rate of liquid delivery would have to be run to deliver 65 ml. of liquid to the patient.

If, after delivering the 65 ml., the physician decides that he wants to resume the parenteral liquid delivery at a constant rate until bottle 3 is empty the nurse simply closes off valve 17 and partially refills enlarged chamber 4 while valve 11 remains open. Next, valve 17 is closed and administration of liquid at the drip rate desired is controlled by roller clamp 12. Alternatively, the enlarged semi-rigid chamber 4 can be partially filled with liquid after valve 17 is closed. This is done by slightly squeezing the transparent wall 5 and releasing it to suck liquid back into the enlarged chamber. Such squeezing and filling procedure is conventional.

Having described the method by which the administration set of my invention can be changed to indicate a "rate" or a "volume" delivery. The details of the specific top cap 8 and valve system which accomplishes this will be explained. As shown in FIG. 3, the top cap 7 includes top wall 23 and a pair of downwardly extending skirts 24 and 25 which are cemented or otherwise bonded to tubular wall 5 of the enlarged chamber. The top wall has an inlet opening surrounded by a drip tube structure 26. Fitting within this drip tube structure is flexible conduit 1. Thus as liquid drains from bottle 3 through conduit 1 it forms a drip on the drip tube 26 within the enlarged chamber.

Top wall 23 has an upstanding tube 27 closed by a puncture pad 28 for injecting additional medication into the enlarged chamber. Injections into the chamber can be made through this puncture pad whether the system delivering is in FIG. 1, or as in FIG. 2.

The valve 17 on the top wall 23, of top cap 8, includes a large upstanding rigid tube 29 in FIG. 3 surrounding a vent port 30' through the top wall 23. FItting over this upstanding tube 29 is a rotatable cap 31 with a laterally protruding handle 32. This cap and upstanding tube 29 form an airtight fit with siliconized surfaces. The closure has a circumference rib 34 of the upstanding tube 29. Extending upwardly from a lower end 34 of the cap is a vertical groove 35. This groove 35 stops short of top wall 36 of the cap. The upstanding tube 29 also has a vertical groove 37 which extends from its top wall 38 downwardly but stops short of top wall 23 of cap 8. The two vertical grooves 37 and 35 overlap at a center portion of the valve when the cap is fitted to the upstanding tube 29. How this overlapping relationship works is probably best illustrated in the exploded perspective view of FIG. 8.

To limit its rotational movement to less than 360.degree. cap 31 has an internal radial groove 39 extending partially around its periphery. At each end of groove 39 are shoulders 40 and 41. These shoulders abut a stop lug 42 at a base of the upstanding tube 29. When shoulder 41 abuts lug 42 the grooves 35 and 37 are aligned for passage of air through vent passage tube 29. When shoulder 40 abuts lug 42 the grooves 35 and 37 are sufficiently misaligned that air is prevented from passing through vent passage 30.

Vent passage 30 of upstanding tube 29 has a filter member 43 there across which is solvent or sonic welded to the tube 29. This filter member is of porous polymeric sheet material such as Teflon that is pervious to air but impervious to liquid. The purpose of filter 43 is to keep any splashing liquid from the enlarged chamber 4 from contaminating the inner connecting air passages 35 and 37.

As shown in FIG. 8 the cap has been exploded away from the upstanding tube 29. This is merely for purposes of illustration and the cap and upstanding tube as actually used would be snapped together. Preferably lettering 44 is included on the cap to indicate which direction to turn of opening and closing the valve.

In the above description and drawings I have described an enlarged chamber 4 which can give an indication of "rate" or "volume" parenteral liquid delivery, depending on how the valve 17 is turned. It is also possible to get simultaneous readings of these two measurements. This is done by including a secondary drip 13. Referring to FIG. 2 the secondary drip chamber 13 can indicate a flow rate simultaneously with the volume measuring liquid level lowering operation of enlarged chamber 4. If desired, the drip forming tube 45 within secondary drip member 13 can be of a much smaller diameter than drip tube 26. This can be a small drip formerly known as a "pediatric" drip for administering at very slow rates to infants.

In the above specification and drawings I have used specific examples to illustrate my invention. However, it is obvious to those skilled in the art that certain modifications and changes can be made to these embodiments without departing from the spirit and scope of the invention.

Claims

I claim:

1. A system comprising an administration set for optionally dispensing medical liquid by a continuous rate in drops or as a measured volume without disconnecting the administration set from a liquid supply source, comprising in combination:

a liquid supply container having a lower outlet through which liquid descends;

a supply of medical liquid in said container;

a calibrated-volume housing including a transparent tubular wall having top and bottom end closures;

said top end closure having an inlet opening and

said bottom end closure having an outlet opening; a filling conduit connected in series between the outlet opening of said liquid container and the inlet opening of said top end closure,

said filling conduit being substantially smaller in cross section than either the liquid supply container or the calibrated volume housing,

said top end closure including a drip tube connected to said fluid conduit and depending into said housing and including a terminal discharge end substantially immediately below said top end closure and being of a size for forming countable drops of the medical liquid as it drops onto a level of liquid in said housing;

a first two-position valve having "open" "closed" settings and being interposed in said filling conduit for controlling the flow of liquid into said housing from said liquid supply container;

said top end closure having an air vent means for connecting the housing to atmospheric pressure;

a second two-position valve having "open"-"closed" settings and being connected to said air vent for sealing off the interior of the housing from atmospheric pressure or opening the interior of the housing to atmospheric pressure thereto; and

a dispensing conduit substantially smaller in cross section than said housing and connected to the bottom end closure outlet opening, said set providing means for administering liquid as a continuous rate directly from the liquid supply container or as a measured volume from the housing when one of said valves is in an "open" setting and the other is in an "closed" setting.

2. The combination as set forth in claim 1 wherein the chamber has an upstanding rigid tube around its vent opening with a passage through the tube into the chamber, and a filter member spans this passage.

3. The combination as set forth in claim 2 wherein the manually openable closure forms an airtight fit with the upstanding tube and is rotatable relative thereto, and said upstanding tube and closure having alignable groove systems.

4. The combination as set forth in claim 3 wherein the cap has a laterally extending handle to provide a visual indication of its angular position showing whether the vent passage is open or closed.

5. The combination as set forth in claim 3 wherein the upstanding rigid tube has a groove system on its outer surface and said closure system is a cap fitting over said upstanding tube, said cap having a groove system on its inner surface.

6. The combination as set forth in claim 5 wherein the cap has a vertical groove along a lower portion of its inner surface; the upstanding rigid tube has a vertical groove along its upper portion; and said two vertical grooves overlapping when they are rotationally aligned with each other, so that air can enter and exit through the aligned interconnecting grooves.

7. The combination as set forth in claim 5 wherein the system has rotational limit stop means to confine the closure rotation of the cap on the upstanding tube to less than 360.degree..

8. The combination as set forth in claim 7 wherein the rotational stop means is a protruding lug at a base of the upstanding tube, and the cap has a generally cylindrical wall with an internal radial slot that receives this lug, said cap having abutting shoulders at opposite ends of said slot for contacting the lug.

9. The combination as set forth in claim 8 wherein one shoulder abuts the stop means when the grooves are rotationally aligned for air passage, and the other shoulder abuts the lug when the grooves are sufficiently misaligned so as to fully shut off air passage through the vent opening.

10. The combination as set forth in claim 5 wherein the cap and upstanding tube have interfitting circumferential groove and rib structure to maintain the cap and upstanding tube together as the cap rotates on the upstanding tube.

11. The combination as set forth in claim 1 wherein the liquid outlet opening has an upwardly facing valve seat therearound, and the chamber has a floating valve member that seals against the valve seat when the vent passage is open and the liquid level within the chamber has dropped to approximately the level of the valve seat.

12. The combination as set forth in claim 1 wherein the set has a secondary drip housing connected to a lower portion of the volumetrically calibrated chamber about the liquid outlet opening, and there is a drip forming tube surrounding the liquid outlet passage and extending into the secondary drip chamber, said secondary drip chamber having a drain port at a lower portion thereof.

13. The combination as set forth in claim 12 wherein the set has conduit means connected to the inlet of the volumetrically calibrated chamber and also has conduit means connected to the drain port of the secondary drip chamber, both of said conduits having liquid flow control valves thereon.

14. A parenteral liquid administration set for selectively dispensing medical liquid by either "continuous drip" or "measured volume," said set including: an enlarged chamber that includes a cylindrical transparent wall with volumetrically calibrated indicia thereon; a top cap fitted to an upper end of the cylindrical wall, said top cap including a liquid inlet opening with an external tubular connector and an internal drip tube about the liquid inlet opening; a filling conduit substantially smaller in diameter than the cylindrical wall, which filling conduit is connected to the liquid opening of the top end; a first valve connected with the filling conduit for opening or closing a passage through the filling conduit; partially along its vertical length, said groove stopping short of the base of the upstanding tube; a circumferential rib on the upstanding tube; an air pervious, liquid impervious filter closing off the passage through said upstanding tube; a cap fitting over and rotationally mounted on the rigid upstanding tube; an internal vertical groove within the cap which vertical groove interconnects with the upstanding tube's external groove at one particular rotational position of the cap, whereby air is admitted into said chamber, said cap rotatable about the upstanding tube to close said vent's air passage; said cap having a circumferential internal groove which receives the rib of the upstanding tube; lateral rotational stop means on the cap and upstanding tube; a bottom cap connected to the transparent cylindrical wall and having an outlet port therein; a float valve means within the calibrated chamber for closing off its outlet as liquid drops to approximately the level of the outlet; a secondary drip chamber connected to the liquid outlet of the calibrated chamber; said parenteral liquid administration set adapted to deliver parenteral liquid at a "continuous drip" or a "measured volume" when only one, but not both, of the two valves is in an open position.