US5570026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Altered fluid conductivity monitor
Assignee: Gambro Renal Products Inc
•
Filing: 1995-05-31
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Granted: 1996-10-29
•
Expires: 2015-05-31
Abstract
Abstract A differential conductivity recirculation monitor quantitatively determines the degree of recirculation in a fistula by comparing the conductivity of blood entering the fistula to the conductivity of blood being withdrawn from the fistula. A discrete quantity of a high conductivity marker fluid is injected into the blood entering the fistula, altering the conductivity of the blood entering the fistula. The altered conductivity blood enters the fistula and, if recirculation is present, co-mingles with blood in the fistula, altering the conductivity of the blood in the fistula in proportion to the degree of recirculation. Blood withdrawn from the fistula has an altered conductivity related to the degree of recirculation. Quantitative values of the conductivity of the altered conductivity blood entering the fistula and the conductivity of the blood being withdrawn from the fistula are measured and a difference determined. The determined difference between the conductivities is used to determine a quantitative measurement of the degree of recirculation in the fistula.
Inventors
- 👤 George W. Buffaloe, IV
- 👤 Francis T. Ogawa
- 👤 James M. Brugger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:46
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/704; G01F1/708; G01F1/7088; A; A61; A61M; A61M1/00; A61M1/14; A61M1/16; A61M1/36; A61M1/3607; A61M1/3609; A61M1/361; A61M1/3612; A61M1/3621; A61M1/3653; A61M1/3655; A61M1/3656; A61M1/3658; A61M1/3669; G01F1/7046; A61M1/3601; A61M1/3603
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
254 words
A tubing set adapted for use with an apparatus for determining a degree of recirculation flow in a zone of a vessel into which a first fluid having a first electrical conductivity is being inserted and from which a second fluid having a second electrical conductivity is simultaneously being withdrawn, comprising: a first conduit adapted to convey the first fluid with the first electrical conductivity before it is inserted into the zone of the vessel, said first conduit comprising a first conductivity cell with a first conductivity cell upstream connection, a first conductivity cell downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches, the upstream connection being connectable to a source of the first fluid; and a second conduit adapted to convey the second fluid with the second electrical conductivity after it is withdrawn from the zone of the vessel, said second conduit comprising a second conductivity cell with a second conductivity cell upstream connection, a second conductivity cell downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches, the downstream connection being connectable to a destination of the second fluid.
Claim 2
Dependent Claim
254 words
A tubing set adapted for use with an apparatus for determining a degree of recirculation flow in a zone of a vessel into which a first fluid having a first electrical conductivity is being inserted and from which a second fluid having a second electrical conductivity is simultaneously being withdrawn, comprising: a first conduit adapted to convey the first fluid with the first electrical conductivity before it is inserted into the zone of the vessel, said first conduit comprising a first conductivity cell with a first conductivity cell upstream connection, a first conductivity cell downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches, the upstream connection being connectable to a source of the first fluid; and a second conduit adapted to convey the second fluid with the second electrical conductivity after it is withdrawn from the zone of the vessel, said second conduit comprising a second conductivity cell with a second conductivity cell upstream connection, a second conductivity cell downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches, the downstream connection being connectable to a destination of the second fluid.
Claim 3
Dependent Claim
29 words
A tubing set as defined in claim 1 wherein the first conductivity cell is adjacent to the second conductivity cell at a first junction in a generally parallel relationship.
Claim 4
Dependent Claim
29 words
A tubing set as defined in claim 2 wherein the first conductivity cell is adjacent to the second conductivity cell at a second junction in a generally angular relationship.
Claim 5
Dependent Claim
77 words
A tubing set as defined in claim 3 wherein: each of the first and the second conductivity cells comprise tubing with cross-sectional configuration defined by a generally semicircular sidewall and an adjacent flat sidewall; the flat sidewall of the first conductivity cell adjoins the flat sidewall of the second conductivity cell at the first junction; and the flat sidewall of the first conductivity cell adjoins the flat sidewall of the second conductivity cell at the second junction.
Claim 6
Dependent Claim
49 words
A tubing set as defined in claim 1 wherein: the zone of the vessel is a surgically formed arteriovenous fistula; the first conduit is an outlet line of a medical device for blood processing; and the second conduit is an inlet line of the medical device for blood processing.
Claim 7
Dependent Claim
19 words
A tubing set as defined in claim 5 wherein the medical device for blood processing is a hemodialysis device.
Claim 8
Dependent Claim
29 words
A tubing set as defined in claim 1 further comprising: a hypodermic needle access site in the first conduit in fluid communication with the first conductivity cell upstream connection.
References Cited (Backward Citations)
US2709785A
Cited
US3404336A
Cited
US3396331A
Cited
US3482575A
Cited
US3491592A
Cited
US3619423A
Cited
US3867688A
Cited
US3980946A
Cited
SU521891A1
Cited
US4181610A
Cited
JPS5236990A
Cited
US4081372A
Cited
US4138639A
Cited
US4136563A
Cited
US4361049A
Cited
GB2093192A
Cited
SU1013853A1
Cited
US4508622A
Cited
EP0097366A2
Cited
JPS60190873A
Cited
US4650458A
Cited
US5004459A
Cited
US4739492A
Cited
US4740755A
Cited
US4825168A
Cited
EP0272414A2
Cited
US5092836A
Cited
US4995268A
Cited
US5312550A
Cited
US5312550B1
Cited
US5510717A
Cited
US5510716A
Cited
US5453576A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-29 | 2000-04-29 | 2000-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-29 | 2004-04-29 | 2004-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-29 | 2008-04-29 | 2008-10-29 | $7700.00 | Window Closed / Lapsed |