Patent US4303068A successfully refreshed from Google Patents.
US4303068A
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Method and apparatus for single pass hemodialysis with high flux membranes and controlled ultrafiltration
Assignee: Rensselaer Polytechnic Institute
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Filing: 1978-02-28
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Granted: 1981-12-01
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Expires: 1998-02-28
Abstract
Abstract Disclosed is a method of hemodialysis and a modification for existing hemodialyzers to facilitate use of the method. A highly porous membrane is utilized in a single pass hemodialysis system. The membrane is freely supported, such that it distends in use to maintain a constant transmembrane pressure over its entire surface. The modification to existing dialyzers includes the use of a highly porous membrane, in combination with a transmembrane pressure sensor, which controls the dialysate output flow to maintain a precise transmembrane pressure.
Inventors
- 👤 D. Allen Zelman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:52
CPC Classifications
A; A61; A61M; A61M1/00; A61M1/14; A61M1/16; A61M1/1601; A61M1/1603; A61M1/1605; A61M1/1609; A61M2205/00; A61M2205/33; A61M2205/3331
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
90 words
A method of single pass hemodialysis for removal of metabolites from the blood of a patient including middle molecules of a size on the order of 300 to 2000 daltons, comprising the steps of: providing a single pass hemodialyzer with a freelymounted membrane having an ultrafiltration coefficient of at least 20 ml m -2 hr -1 mmHg -1 ; connecting said patient to said single-pass hemodialyzer in a conventional manner; and operating said hemodialyzer with a transmembrane pressure of between 0 and 30 mmHg to reduce ultrafiltration of the patient.
Claim 2
Independent Claim
90 words
A method of single pass hemodialysis for removal of metabolites from the blood of a patient including middle molecules of a size on the order of 300 to 2000 daltons, comprising the steps of: providing a single pass hemodialyzer with a freelymounted membrane having an ultrafiltration coefficient of at least 20 ml m -2 hr -1 mmHg -1 ; connecting said patient to said single-pass hemodialyzer in a conventional manner; and operating said hemodialyzer with a transmembrane pressure of between 0 and 30 mmHg to reduce ultrafiltration of the patient.
Claim 3
Dependent Claim
118 words
In a single-pass hemodialyzer for hemodialysis of a patient, said dialyzer including a freely-supported dialyzing membrane such that the patient's blood is circulated past one side of the membrane and a dialyzing solution is circulated past the other side of the membrane, there being a transmembrane pressure caused by the blood pressure exceeding the dialysate pressure, said improvement comprising: said membrane is a high flux membrane having an ultrafiltration coefficient of at least 20 ml m -2 hr -1 mmHg -1 and a reflection coefficient of about zero for solutes having a molecular weight up to 2000 daltons; and means for maintaining the transmembrane pressure at between 0 and 30 mmHg at least one point on the membrane.
Claim 4
Dependent Claim
118 words
In a single-pass hemodialyzer for hemodialysis of a patient, said dialyzer including a freely-supported dialyzing membrane such that the patient's blood is circulated past one side of the membrane and a dialyzing solution is circulated past the other side of the membrane, there being a transmembrane pressure caused by the blood pressure exceeding the dialysate pressure, said improvement comprising: said membrane is a high flux membrane having an ultrafiltration coefficient of at least 20 ml m -2 hr -1 mmHg -1 and a reflection coefficient of about zero for solutes having a molecular weight up to 2000 daltons; and means for maintaining the transmembrane pressure at between 0 and 30 mmHg at least one point on the membrane.
Claim 5
Dependent Claim
54 words
The improvement of claim 2, wherein said dialyzer is a co-current dialyzer and said means for maintaining comprises: means for sensing the transmembrane pressure; and pressure control means, responsive to said means for sensing, for adjusting dialysate solution output pressure to a level at which said transmembrane pressure is between 0 and 30 mmHg.
Claim 6
Dependent Claim
55 words
The improvement of claim 2, wherein said dialyzer is a cross-current dialyzer and said means for maintaining comprises: means for sensing a single transmembrane pressure; and pressure control means, responsive to said means for sensing for adjusting dialysate solution output pressure to a level at which said transmembrane pressure is between 0 and 30 mmHg.
Claim 7
Dependent Claim
42 words
The improvement of claim 2, wherein said dialyzer is a co-current dialyzer and said means for maintaining comprises: transmembrane pressure indicator means for indicating to an operator the transmembrane pressure; and clamp means, operable by said operator, for increasing dialysate output pressure.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-30 | 1985-06-01 | 1985-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-30 | 1989-06-01 | 1989-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-30 | 1993-06-01 | 1993-12-01 | $7700.00 | Window Closed / Lapsed |