Methods and apparatus for reducing noise in systems using thermistor catheters to measure biological functions
US5971935A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1998 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | May 1, 2018 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/7203
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A system for measuring biological functions of a patient, such as cardiac output, filters noise from a signal provided by a thermistor catheter inserted into the body of the patient. A signal-conditioning cable is disposed between the catheter and an instrument which processes the signal to measure cardiac output. The cable includes circuitry which forms, in combination with a thermistor of the catheter, a low-pass filter for attenuating thermal and high-frequency noise from the signal provided to the instrument. The instrument can more accurately measure cardiac output with the filtered signal than with an unfiltered signal. Although the circuitry which forms the low-pass filter may be combined with the catheter or the instrument, it is preferred to dispose the circuitry in a separate cable to reduce manufacturing costs of the catheter and retrofitting costs of existing instruments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.