Device, system and method for determining the concentration of a substance in the blood of a subject
US9924896B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2015 |
| Grant date | Mar 27, 2018 |
| Priority date | — |
| Expiry date | Mar 9, 2036 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/7214
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A device for determining the concentration of a substance in the blood of a subject, such as the oxygen saturation, which device reduces or removes the influence of specular reflection and/or subject motion, comprises an input unit for receiving detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, a signal extraction unit for extracting at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, a processing unit for normalizing said at least three PPG signals and forming a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and for forming a ratio between said first difference signal and said second difference signal, and an concentration detection unit for calculating the concentration of a substance in the blood of the subject based on said ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.