Valve connector

Details Valve connector Valve connector

1997-10-23

2001-08-14

Yasko, John D. (Department: 3763)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S088000, C604S905000

Reexamination Certificate

active

06273869

ABSTRACT:

This invention relates to a valve connector. More particularly, this invention relates to a valve connector which may be swabable. Still more particularly, this invention relates to a valve connector having a straight through lumen path for fluids.
As is known, various types of structures have been employed in the medical field for conveying fluids, such as blood, into and out of a patient. For example, there are a number of swabable valve connectors which have been marketed as needleless types and which use multiple flow paths for the fluid which passes to or from a patient. That is to say, the fluid is separated into two or more paths to flow in annular spaces during the time the fluid traverses through the connector. In those cases where the flow path has been unitary, such as through one tube or one lumen, the connectors have suffered from having very limited coupling life. By this is meant that either the connector begins to leak after only a few uses or, in cases where a needle passes through a membrane, coring of the membrane occurs which generally leads to leakage.
Various types of needleless connectors and access devices have been described in U.S. Pat. Nos. 5,549,577; 5,514,116; 5,509,912; 5,487,728; 5,474,536; 5,441,487; 5,380,306 and 5,360,413. International Patent Application WO96/13301 also describes a similar type of infusion device.
Typically, these publications describe structures which employ either a needle having a sharp end for piercing through a membrane or a blunt cannula for passage through a slit membrane. In the case of a needle, a “coring” effect takes place each time the needle pierces the membrane so that after only a few piercings, a leakage path is formed. In addition, during piercing of the membrane, the sharp end of the needle tends to sliver the membrane so that there is a risk that debris may pass into the lumen of the needle and thus into the patient.
In the case of blunt cannulae, it has been found that although the number of penetrations before leakage occurs is greater than with a needle, there is a significant generation of debris which leads to a very limited product life. In this respect, it has been found that when a blunt cannula abuts the membrane, the membrane penetrates slightly into the opening of the cannula so that the sharp corners which typically exist on the inside diameter of the cannula abrade the membrane so that debris is formed which passes into the lumen of the cannula. As the blunt cannula continues to penetrate through the membrane, the sharp internal corner of the cannula scrapes along the face of the membrane creating a slivering action.
Accordingly, it is an object of this invention to be able to repeatedly open and close a connector without leakage and coring of a membrane of septum.
It is another object of the invention to be able to introduce a guide wire, needle or cannula within a seal area of a valve for extended periods of time without loosing valve sealing properties.
It is another object of the invention to be able to retrofit existing connector housings with a valve structure.
It is another object of the invention to reduce the risk of forming debris when passing a smooth cannula through a slit septum.
Briefly, the invention is directed to a connector comprised, in part, of a pre-pierced septum (or membrane) of elastomeric material having a preformed passage in the form of a slit or preformed hole therein and a hollow cannula for penetrating the septum through the preformed passage wherein the cannula has an open distal end for passage of fluid therethrough and wherein the end has a peripheral wall terminating in a smooth surface for penetrating into the septum without generating debris from the septum.
Typically, the peripheral wall of the distal end of the cannula is folded inwardly to define a rounded surface, for example the rounded end of the cannula can be formed employing eyelet technology.
It has been found that when a smooth cannula is used as the interfacing object between the pre-pierced septum and the cannula (fluid conveying lumen), the risk of generating debris is severely limited. In addition, the risk of leakage is substantially reduced. The reason for this is that as the cannula is advanced into the slit septum, a portion of the septum enters into the inner diameter of the cannula and then slides over and around the tip portion of the cannula. By having a smooth interface between the cannula and the slit septum throughout this movement, there is no scoring, slivering or abrasion of the septum surface. As a result, a connector using a smooth cannula may be coupled and uncoupled at least one hundred times without loosing leakage properties. In this respect, a smooth cannula may be defined as a cannula tip which is continuous without a sharp edge through that portion which interfaces the septum. Thus, it has been found that the inside portion of the lumen where the septum touches the wall of the lumen is as important as the geometry of the outside of the cannula in order to maintain a seal and minimize debris. A sharp edge, such as a 90° edge, which is quite common with blunt cannula, especially on the inside portion of the lumen, causes almost instantaneous degradation of leakage properties.


REFERENCES:
patent: 5575769 (1996-11-01), Vaillancourt

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