Device for determining depth of anaesthesia
US4788982A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1987 |
| Grant date | Dec 6, 1988 |
| Priority date | — |
| Expiry date | Jan 13, 2007 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/364
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A device for determining the depth of anaesthesia of a patient, the device including an optical measuring means (1) for measuring on a part (2) of the patient an optical parameter such as transmission or reflection, which is influenced by the circulation of the blood through this part of the patient's body, and to produce an electric signal which varies in accord with this parameter. This signal is related to the periodic variations in the blood-pressure of the patient and thus has a frequency which coincides with the heart frequency of the patient and a maximum amplitude and a minimum amplitude which are related respectively to the systolic and diastolic blood-pressure of the patient. The signal is applied to signal processing circuits (3) which determine the variation in the period of the signal (.DELTA.(R-R)) and the variation in its maximum amplitude (.DELTA.P.sub.max) or minimum amplitude (.DELTA.P.sub.min) or in the difference between its maximum and minimum amplitudes (.DELTA.(P.sub.max -P.sub.min)) and construct a magnitude (K) which is proportional to the variation in the period of the signal or is preferably proportional to the ratio between the variation in the period of…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.