Справочник Пользователя для Innokas Yhtyma Oy VC150

7-12

VC150 Vital Signs Monitor

KO00065K

: GE TruSignal enhanced SpO

2

The TruSignal pulse oximetry measurement uses a two-wavelength pulsatile 
system - red and infrared light - to distinguish between oxyhemoglobin (O

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Hb) 

and reduced hemoglobin (HHb).

The light is emitted from the oximeter sensor, which contains the light source 
and a photodetector.

The light source consists of red and infrared light-emitting diodes (LEDs).

The photodetector is an electronic device that produces an electrical current 
proportional to incident light intensity.

The two light wavelengths generated by the LEDs are transmitted through the 
tissue at the sensor site and are modulated by arterial blood pulsation. Since 
other fluids and tissues present generally do not pulsate, they do not modulate 
the light. The pulsatile portion of the incoming signal is used to detect and isolate 
the attenuation of light energy due to arterial blood flow.

The photodetector in the sensor converts the light intensity information into an 
electronic signal. Since O

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Hb and HHb absorb different amounts of the light that 

is emitted from the oximeter sensor, different amounts of light reach the 
photodetector at the selected wavelengths. The electronic signal varies 
according to which light source is “on” (red or infrared) and the oxygenation of 
the arterial hemoglobin. This information is used to calculate the relative 
percentage of O

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Hb and HHb.