Method and apparatus for improved photoplethysmographic perfusion-index monitoring
US5766127A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1996 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Sep 30, 2016 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/14552
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An improved method and apparatus for the monitoring perfusion of the tissue of a patient by arterial blood is provided. An optical path length change is calculated for a number of digitized samples of a received light intensity signal generated by a photo detector that receives light directed into a patient's tissue by one or more light emitting diodes or laser diodes. The optical path length changes are summed over a predetermined time such as one half cardiac cycle or other set interval to generate a perfusion index. An average perfusion index value may also be generated. In calculating the perfusion index spectral content compensation may be employed to compensate for the variety of center wavelengths associated with the spectral contents of various emitters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.