Gima OXY-6 Betriebs- Und Wartungsanweisungen Seite 16

ENGLISH 16
2.4 Principle of Measurement
The measurement of pulse oximeter is that it uses a multi-functional
oxyhemoglobinometer to transmit some narrow spectrum light bands
through blood samples and to measure attenuation of spectrum with different
wavelengths according wo the characteristic that RHb, O2HB, Met Hb
and COHb absorb the light of different wavelength, thereby determining
O2Hb saturation of different fractions. O2Hb saturation is called "fractional"
O2Hb saturation.
Fractional O2Hb saturation = [O2Hb / (RHb + O2Hb + Met Hb + COHb)]
× 100
Oppositely, pulse oxygen oximeter measures functional O2Hb saturation:
Functional O2Hb saturation = [O2Hb / (RHb + O2Hb)] × 100
Present SpO2 oximeter transmits light of two wavelengths only, red light
(wavelength 660 nm) and infrared (wavelength 940 nm), to differentiate
HbO2 from HbR. One side of the sensor contains two LEDs, and the other
side contains a photoelectric detector. SpO2 oximeter measures HbO2
saturation in the blood by the light plethysmograph when the pulse beats.
The result is quite precise when HbO2 saturation is over 70% ~ 95%.
Red light and infrared
emitter 1
Red light and
infrared receiver 2
2.5 Caution
A. The finger should be placed properly (see the attached illustration of
this manual), or else it may cause inaccurate measurement.