| 摘要 |
Methods and apparatus for measuring cerebral O<SUB>2 </SUB>saturation and detecting cerebral hypoxia-ischemia using multi-wavelength near infrared spectroscopy (NIRS). Near-infrared light produced by an emitter is directed through brain tissue. The intensity of the light that passes through the brain tissue is measured using photodiode detectors positioned at distinct distances from the emitter. This process is conducted for at least three wavelengths of near-infrared light. One of the wavelengths used is substantially at an isobestic point for oxy-hemoglobin and deoxy-hemoglobin, but the other two may be any wavelengths within the near-infrared spectrum (700 nm to 900 nm), so long as one of the additional wavelengths is greater than the isobestic point and the other is less than the isobestic point. Tissue oxygenation is calculated using an algorithm derived from the Beer-Lambert law. Cerebral hypoxia-ischemia may be diagnosed using the calculated tissue oxygenation value. |
