Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-05-10
2001-05-15
Seidel, Richard K. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S175000, C604S006160, C604S007000, C604S507000
Reexamination Certificate
active
06231541
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a no-needle blood access device for hemodialysis and a no-needle connecting cannula assembly. More specifically, the present invention relates to a no-needle blood access device for hemodialysis with a mechanism of simple structure, as well as a no-needle connecting cannula assembly which enables a patient to move around with relative freedom during hemodialysis.
DESCRIPTION OF THE PRIOR ART
Hemodialysis is used widely as a remedy for treating kidney insufficiency. In many cases, a surgical short circuit which is commonly referred to as “shunt” is implanted in a blood vessel or blood vessels of the patient suffering from serious kidney disease, because such a patient must receive hemodialysis treatment periodically over a long period of time. Shunts are divided broadly into two categories, internal shunts and external shunts. The internal shunt has a drawback that needle puncture is required during hemodialysis. On the other hand, the external shunt has a high rate of thrombosis and infection, and makes daily life more inconvenient.
To overcome these drawbacks of the prior shunts, a new blood access device for hemodialysis has been proposed. The blood access device given the tradename “Hemasite” conceptually belongs to the external shunt group. The Hemasite blood access device is equipped with a tool that has a back-flow valve for blood, and is adapted to acquire a plentiful blood flow immediately if the tool is simply connected to a circuit leading to a dialyzer. This Hemasite blood access device has an advantage that needle puncture is not required, but due to its complicated structure, it is costly and troublesome to handle.
On the other hand, presently, a circuit for connecting the blood access devices implanted in human bodies to a dialyzer during hemodialysis consists of tubes each having a relatively large diameter, and each of these tubes is short, because the amount of blood circulating outside the body of the patient has to be reduced so as not to load the human body. This is due to the reason that the amount of blood circulating outside the body of the patient becomes large if the circuit is made of long tubes with a large diameter. Accordingly, if the prior circuit is used to hemodialyze, the patient cannot move about freely and must lie on a bed quietly, during hemodialysis.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a blood access device for hemodialysis which does not require needle puncture, and which has a mechanism of simple structure, and which can be manufactured at a relatively low cost, and which is easy to handle, as well as a no-needle connecting cannulas assembly which enables a patient to move around with relative freedom during hemodialysis.
The above and other objects of the present invention can be accomplished by a no-needle blood access device for hemodialysis comprising, an artificial conduit whose opposite ends are anastomosed to a targeted artery or vein; a metallic body, the body including a cylindrical horizontal portion covering the entire circumference of the conduit or an arcuate-shaped horizontal portion covering at least an upper half of the circumference of the conduit, and a cylindrical vertical portion connected to approximately the center of the upper part of the horizontal portion so as to be disposed perpendicularly to the horizontal portion and defining a well therein, the horizontal portion being provided at the part located at the bottom of the well with a first pair of apertures, the conduit being provided at the corresponding part with a second pair of apertures, whereby the well is in communication with the conduit through the apertures; and a pair of shutters slidably housed within opposed pockets formed in the upper part of the horizontal portion respectively and arranged such that they can be opened and closed; whereby the device is arranged such that, when the shutters are opened, the well is brought into communication with the conduit, and when the shutters are closed, the well is brought out of communication with the conduit.
Further, the above and other objects of the present invention can be accomplished by a no-needle connecting cannula assembly for hemodialysis comprising, a cap provided with a pair of through-holes; a first pair of cannulas connected to one end of the through-holes respectively so as to be in communication with the corresponding through-holes, the external diameter of the respective leading ends of the cannulas being selected to be slightly smaller than the diameter of the apertures, the external diameter of the respective ends of the side of the cannulas to which the cap is connected being selected to be slightly larger than the diameter of the apertures; and a second pair of cannulas connected to the other end of the through-holes respectively so as to be in communication with the corresponding through-holes and adapted to define a connecting circuit leading to a dialyzer, the second pair of cannulas having an internal diameter approximately equal to the internal diameter of each of the first pair of cannulas, the second pair of cannulas being at least 3 meters in length, one of the second pair of cannulas being provided at an end proximal to the dialyzer with a terminal for connecting to a terminal of the dialyzer, the other of the second pair of cannulas being provided at an end proximal to the dialyzer with a terminal for connecting to a terminal of the dialyzer.
In a preferred aspect of the present invention, each of the shutters of the no-needle blood access device for hemodialysis is provided at their opposite ends with upwardly extending projection pieces, respectively, and the projection pieces serve as a knob during the opening and closing of the shutters.
In another preferred aspect of the present invention, one of the projection pieces of the no-needle blood access device for hemodialysis is formed to be higher than the other.
In a further preferred aspect of the present invention, each of the projection pieces of the no-needle blood access device for hemodialysis is mounted on the shutters, respectively, so that one of the projection piece shifts slightly with respect to the other in a horizontal direction along those ends.
In a further preferred aspect of the present invention, the end of the first shutter of the no-needle blood access device facing the second shutter is provided with a recess or a stepped part, and the end of the second shutter facing the first shutter is provided with a projection or a stepped part adapted to mate with the recess or the stepped part when the shutters are closed.
In a further preferred aspect of the present invention, the first pair of cannulas of the connecting cannula assembly curve so that the curvature becomes larger from the end proximal to the cap towards the end distal to the cap.
In a further preferred aspect of the present invention, the first pair of cannulas of the connecting cannula assembly curve so that the curvature becomes larger from the end proximal to the cap towards the end distal to the cap and intersects at a location adjacent to the end proximal to the cap.
In a further preferred aspect of the present invention, when each of the first pair of cannulas is inserted from the apertures of the body of the blood access devices for hemodialysis through the artificial conduit into the targeted artery or vein, the length of each of the first pair of cannulas of the connecting cannula assembly is selected so that the distance between the anastomosis area of the artificial conduit to the targeted artery or vein and the respective leading ends of the first pair of cannulas is about 3 centimeters.
REFERENCES:
patent: 3826257 (1974-07-01), Buselmeier
patent: 4559039 (1985-12-01), Ash et al.
patent: 4822341 (1989-04-01), Colone
A.J. Collins, et al., Blood Access Without Skin Puncture, vol. XXVII Trans Am Soc Artif Inter Organs, 1981, pp. 308-313.
A.A. Kaplan, et al., Regional Experience with the Hemasite™ No-Needle Access De
Griffin & Szipl, P.C.
Maynard Jennifer
Seidel Richard K.
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