Method and apparatus for detecting optical pulses
US4934372A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 5, 1989 |
| Grant date | Jun 19, 1990 |
| Priority date | — |
| Expiry date | Apr 5, 2009 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/7257
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method and apparatus for improving the calculation of oxygen saturation and other blood constituents by non-invasive pulse oximeters. The method and apparatus permit more accurate determination of blood flow by collecting time-measures of the absorption signal at two or more wavelengths and processing the collected time-measure to obtain composite pulsatile flow data from which artifacts have been filtered. The processing may occur in the time domain or in the frequency domain. In the preferred time domain embodiment, successive portions of periodic information are weighted and added together in synchrony to obtain the composite pulse information. In the preferred frequency domain embodiment, the time-measure in Fourier transformed into its spectral components to form the composite information. A new method and apparatus for correlating the heartbeat and optical pulse is provided whereby a product of the ECG R-wave and optical pulse signals corresponding to the same heartbeat is obtained, and one signal is time shifted relative to the other until a maximum waveform product corresponding to the heartbeat is determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.