Not Applicable
Not Applicable
Not Applicable
The present invention relates to a negative pressure chamber designed to ensure complete delivery of intravenous medication in an intravenous IV medicine delivery system.
Saline intravenous drip bags are well known in the art and have been in use for many years. The saline drip bag delivers a saline solution (typically purified water with NaCl 0.9%) to the patient. The saline drip bag is held on a post or frame above the patient, with a primary tube that runs to the patient and that ends in a needle or cannula that is inserted into the patient. The needle or cannula is inserted directly into one of the patient's veins, typically at the inside of the elbow or the back of the hand. The process is known as intravenous delivery, since it delivers the solution directly into the patient's vein. The saline solution, or other liquids delivered through this system, is delivered into the patient by means of gravity.
There are two primary purposes for the saline drip bag. The first is to help provide liquids to the patient, and ensure the patient is properly hydrated. The second purpose of the saline drip bag and IV system is to ease and expedite delivery of medicine to the patient. The use of the IV system allows the patient to have a single needle, often called a catheter, inserted into the vein, and then to have a variety of medicines or other liquids delivered directly into the patient through the IV system. This means that medical staff only have to insert a needle into the patient's body a single time. The use of IV for delivery of medicine is also preferred since it allows the medicine to be inserted directly into the blood stream, and this allows it to be distributed throughout the body by normal circulation.
In many situations medicine is also delivered to the patient in conjunction with the primary solution bag. This is typically accomplished by the addition of a secondary drip bag that will be attached above the primary bag, with a secondary tube that runs from the secondary bag and attaches to the primary tube below the primary bag. The secondary tube is attached to the primary tube with a Y-site attachment port. Such Y-site attachment ports are well known in the art. This allows the medicine to flow from the secondary bag to the primary tube and into the patient. Because of gravity and hydraulic pressure, the solution from the secondary bag will flow into Y-site before the saline solution. The secondary solution with the medicine will flow into the primary tube until the secondary bag empties, and until the fluid in the secondary tube is parallel to the fluid in the primary bag. At that point hydraulic pressure will reverse the process, and the liquid in the primary bag will flow, leaving a portion of the medicine that remains in the secondary tube unused. The unused medicine remaining in the secondary tube is typically referred to as the residual volume. This is simply wasted medicine, and this waste of medicine can be both costly and inefficient. There is a need, therefore, for a way to eliminate this residual volume and ensure that all of the medicine from the secondary drip bag is fully used.
This invention consists of a small cylindrical negative pressure chamber that is located below the secondary drip bag containing liquid medicine. The negative pressure chamber is designed to ensure that all of the liquid medicine flows out of the secondary liquid medicine bag and then to release the saline within the negative pressure chamber to flush all of the residual liquid medicine from the secondary delivery tube and thereby ensure that all of the liquid medicine is fully used.
Detailed embodiments of the present invention are disclosed herein. It is to be understood that the disclosed embodiments are merely exemplary of the invention, and that there may be a variety of other alternate embodiments. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components.
Therefore, specified structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art to employ the varying embodiments of the present invention.
The present invention is designed for use in conjunction with a standard IV delivery system.
The standard IV system relies upon ambient air pressure, also referred to as atmospheric pressure, and gravity to ensure the flow and delivery of the liquids, both the saline solution S and the liquid medicine M. Both the primary bag 90 and the secondary bag 70 are made of soft plastic and so the liquids contained within the bags are subject the forces of atmospheric pressure. Because of the importance of the forces of gravity, the system described herein is oriented within standard spatial orientation, with up meaning away from the floor or ground, down meaning towards the floor or ground, above meaning higher than another element above the ground, and below meaning lower than another element toward the ground. The liquid in the system, meaning the saline solution S in the primary bag and the liquid medicine M in the secondary bag, flow downwardly due to gravity. The effects of gravity, and hydraulic pressure—which is a combination of the forces of atmospheric pressure and gravity on the liquids within the system—means that the liquids within the system will, whenever, possible, seek to achieve equal hydraulic pressure. The exception to this occurs in the negative pressure chamber 20, as described below. In the typical intravenous system the patient P receives a steady infusion of saline at a rate of between 5 ml and 20 ml per hour, which is referred to as the “keep vein open” rate. This means that the primary saline bag 90 is always connected and always flowing. Some systems also can be attached to an infusion pump that is located on the primary line 92, and that can more precisely control the rate of flow of saline or medicine. The use of an infusion pump has no impact on this invention.
The thorough medicine delivery system 100 of the present invention is attached below the secondary IV bag 70, which contains liquid medicine M.
A standard IV tube is attached to the discharge attachment at the bottom of the drip chamber 12 and then runs into the negative pressure chamber 20. This tube will be referred to herein as the vertically intersecting tube 16. The vertically intersecting tube 16 runs internally through the negative pressure chamber 20. The negative pressure chamber 20 is shown in detail in the perspective view of
The negative pressure chamber 20 is an enclosed, hard, cylindrical compartment, which is intersected in the center by the vertically intersecting tube 16. The negative pressure chamber 20 is made of hard and non-pliable plastic to prevent the forces of atmospheric pressure from acting on the liquids within the negative pressure chamber 20. The negative pressure chamber 20, like most of the components in the IV system, is clear to allow medical personnel to observe the operation of the system and the flow of the liquids and liquid medicine M. In the preferred embodiment this is #5 plastic or polypropylene, but any clear, hard, medical grade plastic can be used. In the preferred embodiment the negative pressure chamber 20 is approximately the size of an 8 Dram pill vial, which equates to 29.57 milliliters in volume. The dimensions of the negative pressure chamber 20, in the preferred embodiment is 66 mm (2.598 inched) high, with a 28 mm (1.102 inch) diameter top. The size of the negative pressure chamber 20 can vary but in all configurations it is a short cylindrical chamber with a cylindrical side wall, a top 21 and a bottom 23. There is a chamber opening 22 located in the center of the top 21. The chamber opening 22 is a circular hole that is sized to allow the vertically intersecting tube 16 to enter the negative pressure chamber 20, and the chamber opening 22 is sized to snuggly and securely encircle the vertically intersecting tube 16 such that the seal between the vertically intersecting tube 16 and the chamber opening 22 is air tight. Standard IV tubing is made of soft, flexible, and pliable material (typically soft pliable polyvinyl chloride), and it is common to make openings that are sized to allow the IV tubing to be inserted, but to maintain an air tight seal. It is possible, and within the conception of the invention, to also include a standard grommet to create the air tight seal between the vertically intersecting tubing 16 and the chamber opening 22.
There are three embodiments of an air opening that allow the negative pressure chamber 20 to be opened to the air during the set-up of the system, but then resealed to be air-tight, and to separate the negative pressure chamber 20 from normal atmospheric pressure. As described herein, the three air openings are an air-tight lid 42, a needleless connection with a Luer lock 41, and a snap-open cap 43. In the preferred embodiment, shown in
At the bottom 23 of the negative pressure chamber 20 there is a conical extension 24, which is conical shaped and extends downwardly from the suction chamber 20. The conical extension 24 is aligned with the center point of the bottom 23 of the negative pressure chamber 20. In the preferred embodiment the conical extension 24 has an approximately 10 mm inner diameter and is approximately 20 mm in length, and tapers from the 10 mm diameter down to a diameter to allow attachment of a standard IV tube, which is either 3 mm or 4 mm depending upon the tubing used throughout the system. The inner wall 28 of the conical extension 24 can taper down in straight line, leaving the inner wall 28 flat and conical, or can be curved downwardly, narrowing more at the end than at the top. Either configuration will accommodate the operation of the invention. The conical extension 24 can be made from the same material as the negative pressure chamber 20 and in one embodiment is molded as a single piece with the negative pressure chamber 20. In other embodiments it can be made of different material and attached to the bottom of the negative pressure chamber 20. The terminal end 17 of the vertically intersecting tube 16 terminates inside the conical extension 24 just below the bottom 23 surface of the suction chamber 20, as shown in
The conical extension 24 is attached at the bottom to the secondary delivery tubing 33, which delivers the liquid medicine M or saline solution S to the patient P. The conical extension 24 tapers down to a sufficiently narrow size to allow the standard delivery tubing 33 to slide over the bottom end of the conical extension. Typically, after leaving the conical extension 24 the delivery tubing 33 is attached to the Y-site 93, so that the liquid medicine M flows from the delivery system 100 then to the primary tube 92 and on to the patient P.
In use, the negative pressure chamber 20 is partially filled with a saline solution S, which is the standard 0.9% NaCl with purified water solution. This can be seen in
The second force that holds the liquid within the straw is known as the capillary force. The capillary force is a product of the intermolecular forces between the liquid and the walls of the components. It is well known that liquids like water can be drawn up against the forces of gravity within very small inner diameter tubes simply by these capillary forces. The Young-Laplace equation explains the capillary force and notes that it is, in part, a product of the surface tension between the liquid and the surfaces surrounding the liquid. In the aforementioned straw, the surface tension between the interior wall of the straw and the water in the straw is enough to overcome the forces of gravity and help retain the liquid within the straw. The same phenomena occurs within the conical extension 24 due to the surface area of the outer wall 18 of the terminal end 17 of the intersecting tube 16, and the inner wall 28 of the conical extension 24. The terminal end 17 descends 5 mm into the conical extension 24, and there is a 2 mm to 2.5 mm gap between the external wall of the terminal end 17 and the interior wall of the conical extension 24. When combined with the lack of ambient air pressure on the liquid saline S within the negative pressure chamber 20, this narrow gap between the two walls provides sufficient surface tension to hold the liquid saline S within the negative pressure chamber 20.
The term “negative pressure” as used in negative pressure chamber 20 is a slight misnomer because the pressure in the negative pressure chamber 20 is not negative. But it is less than the ambient atmospheric pressure acting on the rest of the system so it is negative in relation to ambient pressure, and so the term negative pressure is used. When exposed to atmospheric pressure all of the liquid in the standard IV delivery system will flow downward and will seek equilibrium, because all parts of the system are subject to the forces of gravity and atmospheric pressure. When the negative pressure chamber 20 is filled with liquid saline solution S and then sealed, it is no longer subject to atmospheric pressure and so the liquid will not flow downward.
Next the spike 10, drip chamber 12, and negative pressure chamber 20 with the saline solution S therein, is raised up to the secondary bag 70. The air vent 11 below the spike 10 will be open so that the liquid medicine M in the secondary bag 70, the spike 10, and the drip chamber 12 will be subject to normal atmospheric pressure. The negative pressure chamber 20 should be at a higher level than the primary bag 90 so that the liquid medicine M will from through the system before the saline solution S. This is shown in
The negative pressure chamber 20 allows all of the liquid medicine M to leave the secondary bag 70 and the drip chamber 12 and flow down the vertically intersecting tube 16, past the liquid level L, and to the terminal end 17. Once the last of the liquid medicine M reaches the terminal end 17, air from the drip chamber 12 will enter the bottom of the negative pressure chamber 20. Typically, this occurs through small air bubbles. Since the air from the drip chamber 12 is open to the ambient air, through the air vent 11 in the spike 10 and drip chamber 12, this will equalize the air pressure throughout the system and the air bubbles that come through the terminal end 17 will break the capillary bond at the terminal end 17 and between the outside wall 18 and inside wall 28 of the conical extension 24. Once this capillary bond is broken, the liquid saline solution S will begin to flow from the negative pressure chamber 20. Any air from the intersecting tube 16 will flow to the top of the negative pressure chamber 20 and will not enter the system. The flow of the liquid saline solution S will flush the liquid medicine M down the delivery tube 33. This will ensure that all of the residual liquid medicine M that is typically stranded in the delivery tube 33 is flushed from the system and is therefore fully used.
The present invention is well adapted to carry out the objectives and attain both the ends and the advantages mentioned, as well as other benefits inherent therein. While the present invention has been depicted, described, and is defined by reference to particular embodiments of the invention, such reference does not imply a limitation to the invention, and no such limitation is to be inferred. The depicted and described embodiments of the invention are exemplary only, and are not exhaustive of the scope of the invention. Consequently, the present invention is intended to be limited only be the spirit and scope of the claims, giving full cognizance to equivalents in all respects.
This application claims priority to U.S. provisional application Ser. No. 62/645,954, filed on Mar. 21, 2018, and incorporated herein by reference.
Number | Date | Country | |
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62645954 | Mar 2018 | US |