Method and apparatus for continuous cardiac output monitoring
US6325762A · kind A · utility
Inventor
Key dates
| Filing date | Aug 23, 1999 |
| Grant date | Dec 4, 2001 |
| Priority date | — |
| Expiry date | Aug 23, 2019 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/0538
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An apparatus for continuous cardiac output monitoring ascertains cardiac output by measuring the cross-sectional area of the vessel and the flow rate of fluid flowing through the vessel. The cross-sectional area is derived from the measured resistance within the vessel whereby a pair of signal electrodes injects a known electrical signal into the vessel and the resistance is derived from the known signal and the differential voltage between first and second measuring pairs of electrodes. Resistivity of the fluid is a component of the cross-sectional area derivation, and a temperature sensor is provided to allow for compensating for variations in resistivity with temperature. A velocity sensor is preferably of an optic fiber, Doppler shift type, and the accuracy of the velocity measurement is improved by focusing light emissions from the optic fiber(s) by either providing a Fresnel plate on the terminal end of the fiber or by forming the terminal end of the fiber in a generally conical shape.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.