Haemoglobin measurement appts. for measuring haemoglobin concentration in living tissue of patient

摘要

The measurement appts. has a light emitting device (4) to irradiate living tissue (5) with light of different wavelengths ( lambda 1- lambda 4). At least one of these wavelengths is optically absorbed by water. A photoelectric convertor (6,7) converts the light emitted, which passes through the tissue, into an electric signal. An optical density variation calculating device (11) derives an optical density variation for each wavelength from the pulses of the output values of the photoelectric convertor. The density variation is the difference between the pulses due to the blood and the pulses due to the tissue. The optical density ratio calculating device determines a ratio of the optical density variation for the wavelengths which are determined by the optical density ratio variation device. A haemoglobin concentration calculating device determines a total haemoglobin concentration and/or respective haemoglobin concentrations from the output of the optical density ratio calculating device.