Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-10-07
2001-04-17
Nguyen, Anhtuan T. (Department: 3734)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C264S338000
Reexamination Certificate
active
06217560
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to fitments for connecting medical devices, and in particular, to luer fittings having a textured contact surface.
A conventional luer fitting or fitment generally comprises a conically-shaped element which is adapted to form a relatively air-and-liquid tight seal when mated to a complementary fitting, as for example, a syringe tip to a catheter hub. The surface of the luer fitting which contacts the complementary fitting is ordinarily smooth. Such luer fittings are well known in the art, see International Standard Organization (ISO) 594/1-1986, and have been incorporated into a variety of medical devices.
Once connected, it is important that luer fitments do not become accidentally disengaged during a medical procedure. Such accidental disengagement could result in fluid loss or fluid contamination, which in turn, could have adverse consequences for a patient.
Under most circumstances, the frictional fit between conventional mated luer fitments is sufficient to prevent accidental disengagement of the fitments. However, when fluid contaminants or wetting agents are present between the contact surfaces of mated luer fittings, the fluid contaminants tend to act as a lubricant. The lubricating nature of the fluid contaminants diminishes the frictional force, otherwise known as “engagement force”, which must be overcome to separate the luer fittings, and thus increases the possibility of accidental disengagement of the fittings.
Various solutions have been proposed in the prior art to overcome the problem of fluid contaminants lubricating luer fittings. For example, ISO 594-2 1991-05-01 teaches luer fittings with interlocking threads and engagement structure. To connect luer fittings of this design, a medical service provider brings the fittings together, and then secures them with a twisting motion. While this may be a practical solution for many applications, it may be undesirable where rapid engagement and disengagement of the luer fittings is preferred.
U.S. Pat. No. 4,589,871 to Imbert teaches applying a coating on the exterior surface of a syringe tip (male luer fitment) to increase the roughness of the tip. It is stated therein that increasing tip roughness in this manner increases the frictional fit of mated luer components, making them harder to separate in comparison to identically sized conventional luer fittings. However, such coating processes may involve costly post-manufacturing application and quality control steps. Furthermore, for certain medical applications, it may be desirable to use a luer connector, which in addition to being resistant to the lubricating effects of fluid contaminants, also has a frictional fit which is substantially the same as identically sized conventional luer fittings.
Thus, there remains a need for a luer fitting resistant to the lubricating effects of fluid contaminants and a method of manufacturing the same. Optimally, such a luer fitting could be manufactured by a low-cost process, avoiding the need for application of coatings or use of abrasive as taught by the prior art. Preferably, such a luer fitting would be produced in a manner so as not to substantially alter the frictional fit of the luer fittings in comparison to conventional luer fittings.
SUMMARY OF THE INVENTION
The present invention is directed to a luer fitting with a textured contact surface, which in comparison to conventional luer fittings, exhibits an improved engagement force when fluid contaminants are present between the contact surfaces of mated luer fitments. Advantageously, luer fittings of the present invention can be manufactured by conventional thermoplastic molding techniques, without the need for subsequent coating processes or use of abrasive.
In accordance with one aspect of the present invention, there is provided a syringe having a hollow barrel with an open end and a conical tip. The conical tip is adapted for insertion into a female fitment with a conical inner surface. A plunger assembly is inserted into the open end, the plunger assembly and the hollow barrel defining an internal chamber for retaining fluid. The exterior surface of the tip is textured, such that the force required to disengage the textured tip from the female fitment when a fluid contaminant is present between the tip and fitment is equal to or greater than the force required to disengage the tip and fitment when the tip and fitment are dry.
In accordance with a second aspect of the present invention, there is provided a method of improving the engagement force of a moistened luer fitment by modifying the surface of the luer fitment. To practice the method, a first luer fitment with a textured surface is provided. Then, the first luer fitment is joined with a second luer fitment having a second surface, such that the textured surface contacts the second surface. Advantageously, the textured surface on the first luer fitment is adapted to direct a fluid contaminant away from the textured and second surfaces, such that the force required to disengage the first luer fitment from the second luer fitment when the fitments are dry is equal to or less than the force required to disengage the first luer fitment from the second luer fitment when a fluid contaminant is present between the first and second fitments.
In accordance with a third aspect of the present invention, there is disclosed a method of modifying the surface of a luer fitment so that the engagement force of the fitment in a moistened state equals or exceeds the engagement force in an unmoistened state. The first step of the method is to provide a mold adapted to form a textured surface on a luer fitment. Then, a luer fitment formed of a material deformable by heat or pressure, or a combination of both, is inserted into the mold. Heat and/or pressure are then applied to the fitment by the mold, such that a textured surface is imprinted on the luer fitment. The luer fitment is then permitted to cool, if necessary, and removed from the mold.
REFERENCES:
patent: 2695613 (1954-11-01), MacGregor
patent: 2767710 (1956-10-01), Blackman
patent: 2828743 (1958-04-01), Ashkenaz et al.
patent: 2902995 (1959-09-01), Loper
patent: 3150661 (1964-09-01), Maki
patent: 3469581 (1969-09-01), Burke
patent: 3472227 (1969-10-01), Burke
patent: 4040421 (1977-08-01), Young
patent: 4096229 (1978-06-01), Maivar
patent: 4430080 (1984-02-01), Pasquini et al.
patent: 4589871 (1986-05-01), Imbert
patent: 4822343 (1989-04-01), Beiser
patent: 5017191 (1991-05-01), Yamada et al.
patent: 5026355 (1991-06-01), Sweeney et al.
patent: 5069670 (1991-12-01), Vetter et al.
patent: 5257832 (1993-11-01), Phan et al.
patent: 5263945 (1993-11-01), Byrnes et al.
patent: 5284134 (1994-02-01), Vaughn et al.
patent: 5312352 (1994-05-01), Leschinsky et al.
patent: 5312377 (1994-05-01), Dalton
patent: 5344414 (1994-09-01), Lopez et al.
patent: 5405339 (1995-04-01), Kohnen et al.
patent: 2533594 (1976-02-01), None
patent: 361594 (1931-11-01), None
International Standard (ISO) 594/1 “Conical fittings with a 6% (Luer) taper for syringes, needles and certain medical equipment”—Part 1: General requirements, Ref. No. ISO 564/1-1986 (E).
International Standard (ISO) 594-2 “Conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment”—Part 2: Lock fittings, Ref. No. ISO 594-2:1991 (E).
Leon Miguel
Ritger Philip L.
Knobbe Martens Olson & Bear LLP
Nguyen Anhtuan T.
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