EP0092438A2
Expired / Lapsed
EP
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Method and apparatus for measuring cardiac output
Assignee: Purdue Research Foundation
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Filing: 1983-04-20
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Granted: —
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Expires: 2003-04-20
Abstract
Abstract Cardiac output is measured utilizing an indicator, such as saline, which alters blood resistivity, and an electrically calibrated conductivity cell positioned at the tip of a catheter. The catheter with the tetrapolar conductivity cell at the top is inserted into a blood vessel for current injection to develop a potential which is proportional to blood resistivity for inscribing the dilution curve occurring due to injection of the indicator, which curve is utilized to determine blood flow or cardiac output.
Inventors
- 👤 Leslie A. Geddes
- 👤 David S. Grubbs
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 23:26
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/145; A61B5/14542; A61B5/02; A61B5/026; A61B5/0275; A61B5/1468; A61B5/1473; A61B5/68; A61B5/6846; A61B5/6847; A61B5/6852
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
65 words
An apparatus for enabling measurement of cardiac output by determination of blood resistivity, said apparatus comprising: detector means; positioning means for adapting said detector to be positioned in the flow path of blood; and electrical means including calibration means, said electrical means being connected with said detector means for generating an output that is proportional to the resistivity of the blood in said flow path.
Claim 2
Independent Claim
65 words
An apparatus for enabling measurement of cardiac output by determination of blood resistivity, said apparatus comprising: detector means; positioning means for adapting said detector to be positioned in the flow path of blood; and electrical means including calibration means, said electrical means being connected with said detector means for generating an output that is proportional to the resistivity of the blood in said flow path.
Claim 3
Dependent Claim
24 words
The apparatus of Claim 1 wherein said apparatus includes indicating means for receiving said output from said electrical means and indicating said blood resistivity.
Claim 4
Dependent Claim
14 words
The apparatus of Claim 2 wherein said indicating means includes a digital readout device.
Claim 5
Dependent Claim
26 words
The apparatus of Claim 2 wherein said indicating means includes means for enabling inscribing of the dilution curve indicative of sense changes of said blood resistivity.
Claim 6
Dependent Claim
13 words
The apparatus of Claim 1 wherein said detector means is a conductivity cell.
Claim 7
Dependent Claim
15 words
60 The apparatus of Claim 5 wherein said conductivity cell is a tetrapolar conductivity cell.
Claim 8
Dependent Claim
38 words
7 o The apparatus of Claim 6 wherein said tetrapolar conductivity cell includes a pair of exciting electrodes and a pair of output electrodes, and wherein said electrical means includes a constant-current source connected with said exciting electrodes.
Claim 9
Dependent Claim
21 words
The apparatus of Claim 5 wherein said positioning means includes a catheter having said conductivity cell positioned at the tip thereof.
Claim 10
Dependent Claim
26 words
9 o The apparatus of Claim 8 wherein said conductivity cell is a tetrapolar conductivity cell having four electrodes arranged along said tip of said catheter.
Claim 11
Dependent Claim
39 words
The apparatus of Claim 8 wherein said catheter is adapted for insertion in a blood vessel, has an inflatable balloon therein, and at least a first lumen for inflation of said balloon and a second lumen for injecting indicator.
Claim 12
Independent Claim
133 words
An apparatus for enabling measurement of cardiac output by determination of blood resisitivity, said apparatus comprising: a tetrapolar conductivity cell having four electrodes: a catheter having said conductivity cell positioned on the tip thereof, said catheter being adapted for insertion into a body so that said conductivity cell is in the flow path of blood in said body: a constant-current source connected with two of said electrodes of said conductivity cell; first amplifying means connected with the other two of said electrodes of said conductivity cell; indicating means connected with said first amplifying means for indicating resistivity; isolation means connected with said first amplifying means; and second amplifying means connected with said isolation means and providing an isolated analog output of blood resistivity for enabling inscribing of the dilution curve of blood resistivity.
Claim 13
Independent Claim
133 words
An apparatus for enabling measurement of cardiac output by determination of blood resisitivity, said apparatus comprising: a tetrapolar conductivity cell having four electrodes: a catheter having said conductivity cell positioned on the tip thereof, said catheter being adapted for insertion into a body so that said conductivity cell is in the flow path of blood in said body: a constant-current source connected with two of said electrodes of said conductivity cell; first amplifying means connected with the other two of said electrodes of said conductivity cell; indicating means connected with said first amplifying means for indicating resistivity; isolation means connected with said first amplifying means; and second amplifying means connected with said isolation means and providing an isolated analog output of blood resistivity for enabling inscribing of the dilution curve of blood resistivity.
Claim 14
Dependent Claim
56 words
The apparatus of Claim 11 wherein said electrodes of said conductivity cell are spaced with respect to one another along the end of the tip of said catheter, and wherein said outer two of said electrodes are connected with said constant-current source and the inner two of said electrodes are connected with said first amplifying means.
References Cited (Backward Citations)
No citation records indexed.
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