Near-infrared noninvasive spectroscopic determination of pH
US5792050A · kind A · utility
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Aug 11, 1998 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
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 vitro 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.