Surgery – Means for introducing or removing material from body for... – Material introduced into and removed from body through...
Reexamination Certificate
1999-08-05
2001-01-30
Yasko, John D. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Material introduced into and removed from body through...
C604S033000, C604S236000, C604S246000
Reexamination Certificate
active
06179806
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to catheters for use in medical applications such as hemodialysis wherein fluids are withdrawn and/or introduced into a cavity of the body. The invention relates particularly to a hemodialysis catheter having internal means to automatically stop blood flow after a dialysis procedure has been conducted.
2. Description of the Prior Art
Hemodialysis is a process of mass transfer in which certain chemical substances accumulated in the blood because of kidney failure are transferred from the blood across a semipermeable membrane to a balanced salt solution in a dialysis machine. In a typical hemodialysis procedure, a double-lumen catheter is utilized to simultaneously withdraw blood from a body cavity through one channel or lumen for processing in a dialysis machine and to reintroduce the processed blood back to the patient through a separate lumen.
Such catheters typically include a catheter hub or branch connector for connecting the catheter to tubes leading to and from a dialysis unit. The hub or connector may also be adapted for accommodating injection syringes, or other extracorporeal equipment which may be required for a selected medical procedure. To facilitate connection of the catheter hub to such equipment, the hub typically includes extension tubes which accommodate clamps for opening and closing the fluid passage ways of the respective extension tubes. The clamps serve as on-off valves for controlling the flow of blood between the catheter and dialysis unit or other medical equipment. Typical dialysis catheters are shown in U.S. Pat. No. 5,197,951 and U.S. Pat. No. 5,486,159 both to Mahurkar.
The requirement of extension tubes and clamps to prevent blood flow after a dialysis or other medical procedure has been conducted, makes conventional dialysis catheters somewhat cumbersome and uncomfortable for the patient. Manual operation of the clamps also requires additional manipulation by the dialysis professional to complete the procedure. The external clamps are also prone to tampering and inadvertent opening or loosening.
Accordingly, it would be desirable to provide a small, light-weight catheter which reduces the discomfort to the patient and is also automatic in nature thereby reducing the manipulation required by the dialysis professional to complete the procedure.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a small, light-weight catheter which is uncumbersome and reduces the discomfort to the patient.
It is another object of the present invention to provide a catheter which is automatic in nature requiring minimum manipulation by a medical professional to complete a given medical procedure.
It is a further object of the present invention to provide a catheter which eliminates the need for extension tubes and clamps which are prone to tampering and/or inadvertent opening or loosening.
In accordance with one form of the present invention, a self-occluding catheter generally includes a body portion for connection to extracorporeal equipment and an elongated tubular portion for insertion into a body cavity. The elongated tubular portion may be fixed to or made removable from the body portion. The tubular portion includes at least one lumen which is in fluid communication with at least one internal fluid conduit of the body portion. The body portion also includes an internal transverse bore which is in fluid communication with the internal fluid conduits of the body portion. Supported within the transverse bore is a spool which is slidable between an open and a closed position. A biasing device is provided adjacent the spool for resiliently urging the spool to a normally closed position wherein the spool blocks the internal fluid conduits thereby preventing fluid flow through the body portion. When a positive or a negative fluid pressure is applied to the equipment connection end of the body portion, the spool slides to an open position thereby permitting fluid flow through the body portion. When the fluid pressure is terminated the biasing device returns the spool to its closed position whereby the internal fluid conduits are again blocked.
The biasing device preferably comprises one or more magnets fixed within the body portion which generate a magnetic force for urging a magnetically polarized spool to its closed position. In the preferred embodiment, one or more magnets are integrally molded within the spool to provide the magnetic charge to the spool. The spool is preferably in the form of a cylindrical member having two opposite end portions, a shoulder portion positioned between the end portions and a reduced diameter neck portion positioned between each of the end portions and the shoulder portion. The shoulder portion slides in close fitting relationship with the transverse bore and is acted upon by the positive or negative fluid pressure applied to the equipment connection end to move the spool to its open position. In the spool's closed position, the end portions block both an inlet and an outlet fluid conduit of the body to prevent fluid flow through the body.
A preferred form of the catheter, as well as other embodiments, objects, features and advantages of this invention will be apparent from the following detailed description of illustrative embodiments thereof which is to be read in conjunction with the accompanying drawings.
REFERENCES:
patent: 4668215 (1987-05-01), Allgood
patent: 5034000 (1991-07-01), Freitas et al.
patent: 5197951 (1993-03-01), Mahurkar
patent: 5486159 (1996-01-01), Mahurkar
Hoffman & Baron LLP
Sci-Med Life Systems, Inc.
Yasko John D.
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