Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-10-12
2001-04-24
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S256000
Reexamination Certificate
active
06221050
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a self-retaining needle that is pierced into a blood vessel as in the case of transfusion. It also relates to a valve element for use in the needle.
To perform transfusion on a patient, a self-retaining needle to be connected to a transfusion line is pierced into a blood vessel of the patient and held in position. The self-retaining needle consists of a hollow outer needle, an outer needle hub secured to the basal end of the outer needle, an inner needle that is to be passed through the outer needle and which has a sharp tip point, and an inner needle hub secured to the basal end of the inner needle.
To pierce the self-retaining needle into a blood vessel of the patient, the inner needle is passed through the outer needle and pierced into the vessel as it projects from the tip of the outer needle. When the tip point of the inner needle gets into the blood vessel, the blood flows in through the opening in the tip and passes through the bore of the inner needle until it fills the interior of the transparent inner needle hub. This phenomenon is commonly called “flashback” and is a sign of the inner needle having secured the blood vessel. After the occurrence of “flashback”, both the inner and outer needles are moved forward by a small distance until the tip of the outer needle enters the blood vessel. Then, with the outer needle being held between the finger and thumb, the inner needle is slipped out of the outer needle and the connector of a transfusion line is plugged to the outer needle hub.
The removal of the inner needle and connecting the transfusion line to the outer needle hub must be carried out as quickly as possible. If not, the blood flows back through the outer needle under the blood pressure and leaks out of the opening at the basal end of the outer needle hub to foul the surrounding area.
With a view to solving this problem, it was proposed that an elastic plug through which the inner needle could be pierced should be provided within the outer needle hub so that the liquid-tightness of the plug would prevent the blood from leaking out. An elastic plug assembly based on this idea is described in Unexamined Published Japanese Patent Application (kokai) No. 229133/1996.
The elastic plug assembly however has one major drawback. Before it is used, the inner needle remains pierced through the elastic plug but the portion of the plug which is in contact with the surface of the inner needle deteriorates over time and loses elasticity. If this occurs, the hole remaining after removing the inner needle is not fully closed and the blood may potentially leak out.
To deal with this problem, materials that will not deteriorate over time must be selected and used to make an effective elastic plug. However, the approach of preventing the time-dependent deterioration by selecting appropriate materials has inherent limits. In addition, desirable materials are very expensive and increase the production cost.
BRIEF SUMMARY OF THE INVENTION
The present invention has been accomplished under these circumstances and has as an object providing a self-retaining needle assembly that is free from liquid leakage due to deterioration with time.
Another object of the invention is to provide a valve element for use in the self-retaining needle assembly.
A further object of the invention is to provide a self-retaining needle assembly that allows the blood and other fluids to be injected easily.
These objects of the invention can be attained by the following.
(1) A self-retaining needle assembly comprising:
a hollow outer needle;
an outer needle hub that is provided at the basal end of said outer needle and which has a bore communicating with the interior of said outer needle;
an inner needle to be passed through said outer needle;
an inner needle hub provided at the basal end of said inner needle; and
a valve element provided in the bore of said outer needle hub to plug said bore, wherein
said valve element is a reversible valve element made of an elastic material that has a hole through which said inner needle can be passed.
(2) The self-retaining needle assembly as set forth in (1), wherein said valve element is funnel-shaped in at least the reversible portion thereof.
(3) The self-retaining needle assembly as set forth in (1) or (2), wherein said valve element has a cross section with a noncircular outer periphery before it is reversed and, when it is reversed, the sides that faced outward before the reversal come into close contact with each other.
(4) The self-retaining needle assembly as set forth in (3), wherein the cross section of said valve element before it is reversed has a polygonal outer periphery.
(5) The self-retaining needle assembly as set forth in (3), wherein the cross section of said valve element before it is reversed has an outer periphery consisting of arcs of a circle combined with straight lines.
(6) The self-retaining needle assembly as set forth in any one of (1)-(5), wherein the cross section of said valve element before it is reversed has an inner periphery that is identical or similar to the outer periphery of the cross section of said inner needle.
(7) The self-retaining needle assembly as set forth in any one of (1)-(6), wherein said valve element comprises thick-walled portions and thin-walled portions that extend along the periphery.
(8) The self-retaining needle assembly as set forth in any one of (1)-(7), wherein part or all of said valve element is made of a liquid-tight but gas-permeable material.
(9) The self-retaining needle assembly as set forth in any one of (1)-(8), wherein said valve element has soft portions that are made of a more flexible elastic material than the principal portion of said valve element and which come into contact with each other when said valve element is reversed.
(10) The self-retaining needle assembly as set forth in (9), wherein said soft portions contain an area that progressively decreases in thickness toward the distal end of said valve element.
(11) The self-retaining needle assembly as set forth in (9) or (10), wherein at least said soft portions of said valve element are made of a liquid-tight but gas-permeable material.
(12) The self-retaining needle assembly as set forth in any one of (9)-(11), wherein said soft portions have a rubber hardness (JIS TYPE A) of less than 95.
(13) The self-retaining needle assembly as set forth in any one of (1)-(12), wherein said inner needle is fitted with a reversal assisting means that assists in reversing said valve element.
(14) The self-retaining needle assembly as set forth in any one of (1)-(13), wherein said valve element is reversed with the aid of the friction that develops when said inner needle is pulled out of said hole.
(15) The self-retaining assembly as set forth in (13), wherein said valve element is reversed with aid of the action of said reversal assisting means when said inner needle is pulled out of said hole.
(16) A reversible valve element made of an elastic material that has a hole through which a tubular or rod member can be passed.
(17) The valve element as set forth in (16), which is funnel-shaped in at least the reversible portion thereof. (18) The valve element as set forth in (16) or (17), which has a cross section with a noncircular outer periphery before it is reversed and wherein, when it is reversed, the sides that faced outward before the reversal come into contact with each other.
(19) The valve element as set forth in (18), which has a cross section with a polygonal outer periphery before it is reversed.
(20) The valve element as set forth in (18), the cross section of which before it is reversed has an outer periphery consisting of arcs of a circle combined with straight lines.
(21) The valve element as set forth in any one of (16)-(20), which has a cross section with a generally circular inner periphery before it is reversed.
(22) The valve element as set forth in any one of (18) (21), which comprises thick-walled portions and thin-walled portions that extend along the periphery.
(23) The valve e
Burns Doane , Swecker, Mathis LLP
Nguyen Anhtuan T.
Terumo Kabushiki Kaisha
LandOfFree
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