Near-infrared noninvasive determination of pH in pulse mode
US6073037A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 10, 1998 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Aug 10, 2018 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/6838
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Methods and apparatus for, preferably, determining noninvasively and in vivo pH in a human. The non-invasive method includes the steps of: generating light at three or more different wavelengths in the range of 1000 nm to 2500 nm; irradiating blood containing tissue; measuring the intensities of the wavelengths emerging from the blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths; and determining the unknown values of pH. The determination of pH is made by using measured intensities at wavelengths that exhibit change in absorbance due to histidine titration. Histidine absorbance changes are due to titration by hydrogen ions. The determination of the unknown pH values is performed by at least one multivariate algorithm using two or more variables and at least one calibration model. The determined pH values are within the physiological ranges observed in blood containing tissue. The apparatus includes a tissue positioning device, a source, at least one detector, electronics, a microprocessor, memory, and apparatus for indicating the determined values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.