Background of the Invention
1. Field of the Invention
This invention relates to a system and method for economically transferring a sterile fluid from an enclosed single source in a sterile environment to multiple recipients in successive fashion. More particularly, this invention relates to a low cost, disposable transfer system and method that allows a single reservoir to provide a relatively high flow rate of sterile fluid into several independent paths without danger of cross-contamination between any of the recipients, but with efficient use of the fluid.
2. Description of the Prior Art
Many medical and biologically compatible solutions for human and animal use are supplied in closed sterile containers having fixed volumes (e.g. 500 cc of saline or other isotonic solution). The solution is expensive because of the biologic and sterility requirements that must be met. In a typical widely used surgical procedure in opthalmology, for example, a system is employed in which the eye is irrigated and occasionally aspirated as required. Irrigation is accomplished by feeding the chosen sterile solution into the eye by an implanted or attached device at a controlled rate using a flow control device such as a drip regulating chamber. By far the most widely used system is based on the use of a sterile container having a puncturable elastomeric seal and a disposable administration set having a spike ended conduit at one end, an integral drip chamber, and a needle, catheter or other delivery device at the other end of a flexible tubing. The spike, which is sterile, is used to penetrate into the container through the seal. Since the flow rate can be substantial the size of the conduit must be of moderate size (e.g. 1/8" inner diameter) to allow for unrestricted flow under gravity feed conditions. The administration sets are commercially available products having a number of different forms. Because of cost, ease of use, and reliability this system of spiking into an elastomeric seal is used in the great majority of administration sets. Medical practitioners and hospitals maintain a large inventory of such sets and prefer to use the seal/spike approach for cost and convenience reasons.
While these types of transfer systems maintain the fluid in a sterile condition from the supply container to the individual, they are often quite costly to use because with present devices much of the solution is often wasted. Once the seal is punctured and the spike is removed the seal is no longer sterile. Of the 500 cc in a standard container, for example, only about 20-30% is typically employed in a routine cataract removal, for example. Thus, when the operation is complete, the remainder of the bottle is discarded. Furthermore, using smaller fixed volumes (e.g. 250 cc) of solutions is not cost efficient since they are disproportionately priced in comparison to the larger volumes (e.g. 500 cc), and it is not practical to carry a large inventory of different sized containers or to use very small containers in series.
There are certain known types of connector systems than can fully utilize the sterile solution of a container by enabling successive connection to different individuals. These systems employ a special manifold having multiple ports, each including a special connector and a control valve. Additional tubing sets can be attached if they have special mating connectors. However, the tubing sets then are available only for use in this type of system. Such coupling systems are impractical and too expensive for many applications, because of the cost of the special connectors and attachments.
There is an economic need to utilize all of the sterile solution which is stored in a punctured container. The desired system and method should be able to maintain a high flow rate of the solution, yet yield multiple independent pathways. The independent pathways should be designed so that when one pathway has been used it may be closed off without affecting the sterile condition of the adjacent pathways. The system and method should also allow for multiple withdrawals from the solution without a decrease in flow rate using standard sized medical attachments or the like.
Summary of the Invention
Systems and methods in accordance with the invention employ a container having a sterile solution and transfer means that can be attached to the container so as to deliver the solution at a high flow rate to successive multiple users employing standard medical instruments without the need for special fittings, the fear of cross-contamination or waste of the valuable sterile solution.
In accordance with one aspect of the invention, the spike end of a set including a drip chamber device is inserted into the elastomeric seal of a container for a suitable sterile biological solution, the output end being coupled to a multi-branch flow divider. Separate flow paths from each branch of the divider include delivery funnels having sterile elastomeric seal faces. These seals can be separately punctured by spike-ended devices on commercial administration sets for delivery of solution serially to different users, as previously used tubing lines are clamped off. The contents of a supply container can thus be efficiently used without introducing a significant cost increase in the delivery system.
In a more specific example, a 15 drop drip chamber includes a 1.2 micron hydrophobic filter that is integrally attached to the chamber and acts to stabilize flow rate in the drip chamber by permitting air ingress while blocking fluid passage. The other axial end of the drip chamber connects to a multiple branch coupler having more than one branch, up to a maximum of eleven. Attached to the distal ends of the branch coupler are individual lines of flexible tubing whose opposite ends each terminate at a different specially formed delivery funnel having a transverse puncturable elastomeric seal. The puncture site is sealed in a sterilized manner with a protective ring which is crimped around the outside of the delivery funnel. A plastic divider around the necks of the delivery funnel keeps them separate and apart, holding them in convenient position for use and avoiding any possibility of cross-contamination from contact. A clamp is placed on each flexible tubing length between the branch coupler and the delivery funnel, so that after one branch line has been used it is closed and reverse flow is blocked. This prevents any cross-contamination by transfer of fluid between separate lines and keeps the remaining lines available for use.
Brief Description of the Drawings
A better understanding of the invention may be had by reference to the following description, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of a system in accordance with the invention, showing one administration set in position with another ready for use;
FIG. 2 is a side sectional view of a portion of the system of FIG. 1, showing further details of a puncture spike and drip chamber relative to a supply container; and
FIG. 3 is a side sectional view of a different part of the system showing further details of a delivery funnel, clamp, funnel divider and a second puncture spike.
Detailed Description of the Invention
In accordance with the invention, a closed container 10 of valuable biologic fluid 12 is shown as disposed in a typical surgical situation, inverted for gravity feed down to the operative sets (holding means have not been shown inasmuch as any conventional retainer may be used). The container 10 has a puncturable elastomeric seal 14 at its otherwise open end, transverse to the opening. The seal 14 is originally enclosed by a sterilized protective covering (not shown) that is removable to maintain the seal 14 and fluid in a sterile condition. The seal 14 is of substantial diameter, e.g. greater than 1 2/2". When fluid is desired for a therapeutic or operative purpose the protective covering around the puncturable seal 14 is removed and a dispensing device 16 is attached. The device 16 includes at one end, in this example, a standard sized sterile medical spike 18 which is inserted into the puncturable seal 14 of the container 10. The puncture spike 18 has a tapered tip with surface apertures 19 that extend into communication with a central conduit (not shown in detail) in a cylindrical body 20. The cylindrical body 20 forms the upper end of an integrally attached fifteen drop drip chamber 22 of somewhat flexible material. A second portion of the cylindrical body 20 branches out at an angle in relation to the spike 18 to receive an internal 1.2 micron hydrophobic disk filter 24 that is open to the environment at one side and in communication with the interior of the container 10 and the drip chamber 22 on the other. Bacteria and other contaminants are blocked by the filter 24, although air passes inwardly as the hydrostatic head in container 10 and chamber 22 are lowered. Sterile fluid cannot pass the hydrophobic barrier, and in consequence the flow rate is stabilized.
The drip chamber 22 is an elongated cylinder of conventional design whose distal end is enclosed by an integral cap 26 having a vertically extending hollow output stub 28 in its center. A sterile flow divider comprising a multi-branch coupler 30 has an integral inlet tube 32 coupled to the output stub 28 of the drip chamber 22 and, in this example, three branch outlet conduits 35, 36, 37 on the distal end. There may be at least two and up to a maximum of eleven outlet conduits that branch out from the body of the coupler 30. Attached to each of the branch conduits 35, 36, 37 is a length of flexible (here PVC) tubing 39. The opposite end of each conduit 35, 36, 37 receives the small end of specially formed diverging delivery funnel 41, 42 or 43. Each delivery funnel 41, 42, 43, here of resilient plastic, includes an elastomeric transverse end seal 45 that functions as a puncturable surface for insertion of a standard size puncture spike 50 forming a part of a commercial administration set 51. The administration set 51 typically includes a suitable length of flexible tubing 52 leading to a needle 53 or other element such as a catheter. A separate drip chamber (not shown) is often included in this type of set. The delivery funnel 41-43 has a narrow elongated neck 54 inserted within the tubing 39 and integral with a diverging body 55 which terminates in a concentric mouth having an outer lip 56 around its periphery. The funnel lip 56 acts as a base to securely hold the sterile rubber end seal 45 in transverse position. A flange ring 57 is crimped about the lip 56 of the delivery funnel 41, 42 or 43. A sterile cover 58 is secured over the wide end of the funnel and the outer part of the end seal 45 to maintain the puncture site area in a sterile condition until it is to be used.
The funnels 41-43 are kept in alignment and physically separate by a plastic divider 60 consisting of an integral length of plastic having a plurality of regularly spaced apart surface openings 62. The openings 62 are spaced apart sufficiently to keep the funnels 41-43 separated for easy spike insertion. This also insures that the puncture site of one delivery funnel, e.g. 42, does not communicate with the puncture site of the surrounding delivery funnels, e.g. 41, 43. The number of openings 62 in each plastic divider 60 corresponds to the number of delivery funnels 41-43 being used. The plastic divider 60 is disposed with a snug fit around the neck 54 of a delivery funnel, e.g. 41, so that substantial movement and slippage are eliminated.
A different spring clamp 68, 69, 70 is mounted on each length of tubing 39 between the corresponding branch conduit and respective delivery funnel. The spring clamps, when engaged, close off the flow of fluid from the respective branch conduits 35-37 so that the contents of the container 10 may be delivered to other individuals without the fear of cross-contamination.
The administration sets 51 are sterile, commonly used units having flow openings suitable for relatively high flow rates. The sterile fluid dispensing system of this invention represents a substantial improvement over previous dispensing systems. A number of persons can be served from a single container, the contents of which are thus most efficiently used.
In using the system of this invention a user removes the sterile cover (not shown) from the elastomeric seal 14 of the fluid source container 10, before inserting the sterile puncture spike 18. The puncture spike 18 is forced into the center of the elastomeric seal 14, maintaining the system biologically closed unless the spike 18 is removed. The flexible sides of the drip chamber 22 can then be squeezed to adjust the level. The fluid container 10 may be inverted and placed in position before or after the level adjustment is made. The sterile covering 58 that is held over each delivery funnel 41-43 is now removed from one funnel, e.g. 41. The chosen delivery funnel 41 is held for insertion of the standard size, sterilized puncture spike 50 of an administration set 51 into the center of the rubber end seal 45. The fluid level in the drip chamber 22 can be adjusted by applying pressure to the flexible sides of the chamber 22.
This then enables delivery to the patient or other recipient of the needed amount of fluid 12, typically substantially less than the contents of the container 10. When the procedure is complete for that individual, the clamp, e.g. clamp 68, is closed onto the tubing 39. When a need arises for delivery of fluid to a different individual, the protective sterile covering 58 over the second delivery funnel 42 is removed and the face of the rubber end seal 45 is exposed. The rubber end seal 45 is then penetrated with a second puncture spike 50. Then the drip chamber 22 is squeezed and released for level adjustment. When the recipient's need for fluid 12 is met, the tubing 39, corresponding to the second delivery funnel 42, is closed with another clamp 69. The same process may be repeated for a third recipient, in this example, insuring maximum use of fluid from the container 10.
The system and method of this invention deliver a valuable sterile fluid at a high flow rate to multiple recipients by making it possible to use at least two and up to a maximum of eleven administration sets. Each administration set is insertable into a corresponding delivery funnel and may be closed off with a clamp so that the delivery funnel can be punctured by a standard size medical spike for a first use and later clamped off when this use has ceased. When a need arises for the delivery of the fluid to another patient, the next corresponding delivery funnel is spiked for use, with the prior spike then being removed. This process of spiking and clamping successive delivery funnels in administration sets may be repeated a number of times to deliver sterile fluids at a high flow rate to the recipients without cross-contamination.
Where many administration sets (say eleven) are to be used, the delivery funnels are preferably arranged in a circular pattern for best compactness and accessibility.
Since further changes and modifications of the invention will occur to and can be made readily by those skilled in the art without departing from the inventive concept, the invention is not to be taken as limited except by the scope of the appended claims.