AbTisSpec
AbTisSpec |
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AbTisSpec, a new tissue spectrophotometer for determination of oxygen supply in blood perfused tissues.
In combination with the technique of OptoFlow a new device was developed that measures all oxygen supply parameters of tissue simultaneously. This device is called O2C(oxygen to see) and provides the following functions: Measurement of blood flow, oxygen saturation and hemoglobin amount. For measurement of oxygen saturation and hemoglobin amount only the AbTisSpec has been replaced by the O2C variation O2C-ATS.
The acronym AbTisSpec is put together by syllables for the words Absorption-Tissue-Spectrometry, explaining the measurement principle of the device.
By use of AbTisSpec you get the oxygen saturation of hemoglobin SO2 [%] in any kind of blood perfused tissue. AbTisSpec detects local tissue values right at the position you place the sensor. In one catchment volume, both, the saturation and the value of local hemoglobin amount is determined by the sensor.
Almost all cells in biological tissues have an elementary need of oxygen. Hence oxygen determines the rate of metabolism in the cells. In blood perfused tissue the oxygen gets transported form lung to capillaries bound on hemoglobin. Hemoglobin itself is located in erythrocytes. From the capillaries the oxygen diffuses into the cells where it is consumed.
Arterial blood in the greater cardiovascular system is saturated with oxygen up to almost 100 % by the lungs. Blood in peripheral tissue however shows lesser saturation because the oxygen is taken by the cells. So we find gradients of oxygen saturation along capillaries, where the oxygen is handed over to cells. Therefore low local saturation values are measured at the end of capillaries, close to the collecting venules and veins.
The AbTisSpec is our basic tissue spectrophotometer. As a two channel system it allows the determination of hemoglobin oxygenation SO2 [%] and relative hemoglobin amount rHb [AU] in two tissue layers simultaneously. Channel 1 records the surface or skin hemoglobin saturation of oxygen while channel 2 monitors the oxygen supply and hemoglobin values of the skeletal muscle, due to the extended catchment volume of channel 2.
The AbTisSpec evaluates online the oxygen saturation of hemoglobin at least in two tissue layers, like skin and skeletal muscle.
Light which penetrates into tissue gets changed and takes hereby the colour of blood. With collecting fibers the AbTisSpec detects the light, which is back scattered to the surface of the tissue. By means of colour spectra the oxygen saturation of hemoglobin is analysed. (see chart)
White light, which penetrates through tissue gets changed in its colour by the pigment of blood, which is named hemoglobin. According to the saturation of hemoglobin with oxygen the blood shows a different colour. Fully oxygenated blood - arterial blood - is red, while venous blood with less oxygen shows a violet coloring.
The AbTisSpec calculates by means of a new method local hemoglobin amount. The algorithm shows an excellent performance because the absorption values are generated by evaluation of broadband spectral data.
The measured values are exponentially correlated with the calculated absorption values. Through normalization of measured tissue spectra with a tissue-scattering-spectra the AbTisSpec generates reproducible and quantitative measures of local hemoglobin amount.
The recorded oxygen and hemoglobin values can easily issued by a colour printer or can be transferred to other programs for further scientific evaluations.