Method and apparatus for processing signals used in oximetry
US4800495A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 1986 |
| Grant date | Jan 24, 1989 |
| Priority date | — |
| Expiry date | Aug 18, 2006 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/7239
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The present invention relates to the processing of signals containing information about the pulse rate and oxygen saturation of arterial blood flowing in tissue. These signals have a relatively periodic pulsatile component superimposed upon a varying baseline component. To determine the pulse rate and oxygen saturation from the signals, the positive peaks, negative peaks, and period of the signal must be determined. The present invention accomplishes this by first searching for a sustained positive sloping region of the signal. Then the first derivative of the signal with respect to time is analyzed and points on the signal before and after the occurrence of a slope reversal marked. If the slope at the first point is positive, the interval between the two points is searched for a maximum amplitude that is identified as a positive peak. After the occurrence of a negative sloping region of the signal, another pair of points are marked occurring before and after a subsequent slope reversal. The minimum amplitude of the signal between these points is then identified as a negative peak. For improved accuracy, these positive and negative peaks are then compared with waveform templates to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.