Claims
- 1. A method for accessing a blood vessel, said method comprising:
- percutaneously attaching a catheter to a subcutaneously implanted port, wherein said port is connected to a blood vessel by a cannula having a pressure-responsive valve adjacent to the blood vessel lumen; and
- generating negative pressure in the cannula to draw blood from the blood vessel through the valve into the catheter or returning blood through the catheter to generate a positive pressure to open the valve and pass blood from the cannula into the blood vessel.
- 2. A method as in claim 1, wherein the valve is a slit valve.
- 3. A method as in claim 1, wherein the catheter is attached to the port by penetrating a needle through a membrane on the port.
- 4. A method as in claim 1, further comprising removing the pressure so that the valve closes and fills the cannula with an anti-coagulant fluid.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation of U.S. patent application Ser. No. 08/745,903, filed Nov. 7, 1996, now U. S. Pat. No. 5,755,780, which was a Continuation of application Ser. No. 08/480,117, filed Jun. 7, 1995, now abandoned which was a Division of application Ser. No. 08/183,151, filed Jan. 18, 1994, now U.S. Pat. No. 5,562,617, and also is a Continuation of application Ser. No. 08/634,634; filed Apr. 18, 1996, now U.S. Pat. No. 5,713,859, which was a Continuation of application Ser. No. 08/183,151, filed Jan. 18, 1994, now U.S. Pat. No. 5,562,617, all of which are incorporated herein by reference.
US Referenced Citations (58)
Divisions (1)
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183151 |
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Continuations (3)
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745903 |
Nov 1996 |
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480117 |
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183151 |
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