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Chapter 9: SpO2 & Rainbow Parameters Monitoring
User Manual
(detector). Signal data is obtained by passing various visible and infrared lights (LED's, 500 to
1400 nm) through a capillary bed (for example, a fingertip, a hand, a foot) and measuring
changes in light absorption during the blood pulsatile cycle. This information may be useful for
clinicians. The maximum radiant power of the strongest light is rated at 25 mW. The detector
receives the light, converts it into an electronic signal and sends it to the module for calculation.
Light Emitting Diodes and Detector
Once the signal is received from the sensor, it utilizes Masimo Rainbow SET signal extraction
technology to calculate the patient's functional oxygen saturation (SPO2 (%)), blood levels of
carboxy hemoglobin (SpCO (%)), methemoglobin (SpMet (%)), Total Hemoglobin
concentration (SpHb g/dl) and pulse rate (PR (PPM)).
Signal Extraction Technology (SET)
Masimo (SET) signal processing differs from conventional pulse oximeters. Conventional pulse
oximeters assume that arterial blood is the only blood moving (pulsating) in the measurement
site. During patient motion, however, the venous blood also moves, causing conventional pulse
oximeters to read low values, because they cannot distinguish between the arterial and venous
blood movement (sometimes referred to as noise).
Masimo SET pulse oximetry utilizes parallel engines and adaptive digital filtering. Adaptive
filters are powerful because they are able to adapt to the varying physiologic signals and/or
separate them by looking at the whole signal and breaking it down to its fundamental
components. The Masimo SET signal processing algorithm, Discrete Saturation Transform
(DST), readily identifies the noise, isolates it and, using adaptive filters, cancels it. It then reports
the true arterial oxygen saturation for display on the monitor.
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