Pulse oximeter probe-off detector
US7471969B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 2003 |
| Grant date | Dec 30, 2008 |
| Priority date | — |
| Expiry date | Jan 25, 2027 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2560/0276
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.