Method and apparatus for monitoring blood analytes noninvasively by pulsatile photoplethysmography
US5137023A · kind A · utility
239Cited by
38References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Apr 19, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/14532
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A non-invasive system for measuring the concentration of an analyte, such as glucose, in an absorbing matrix is described. The system directs beams of light at the matrix using an analyte sensitive wavelength and an analyte insensitive wavelength. The principles of photoplethysmography are applied to measure the change in light intensity caused by matrix absorption before and after the blood volume change caused by the systolic phase of the cardiac cycle. The change in light intensity is converted to an electrical signal which is used to adjust the light intensity and as a measure of analyte concentration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.