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Radical-7R Pulse CO-Oximeter Operator’s Manual
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O v e r v i e w
SpHb measurements rely on a multiwavelength calibration equation to quantify the percentage
of carbon monoxide and methemoglobin and the concentration of total hemoglobin in arterial
blood. In an ambient temperature of 35º C the maximum skin surface temperature has been
measured at less than 106º F (41º C), verifi ed by Masimo sensor skin temperature test
procedure.
FUNCTIONAL SATURATION
The Radical-7R is calibrated to measure and display functional saturation (SpO2): the amount
of oxyhemoglobin expressed as a percentage of the hemoglobin that is available to transport
oxygen. Note that carboxyhemoglobin is not capable of transporting oxygen, but is recognized
as oxygenated hemoglobin by conventional pulse oximetry.
Radical-7R vs. DRAWN WHOLE BLOOD MEASUREMENTS
When SpO2, SpCO, SpMet and SpHb measurements obtained from the Radical-7R (non-
invasive) are compared to drawn whole blood (invasive) measurements by blood gas and/or
laboratory CO-Oximetry methods, caution should be taken when evaluating and interpreting the
results. The blood gas and/or laboratory CO-Oximetry measurements may differ from the SpO2,
SpCO, SpMet, SpHb, SpOC, and SpHct measurements of the Radical-7R Pulse CO-Oximeter.
In the case of SpO2, different results are usually obtained from the arterial blood gas sample if
the calculated measurement is not appropriately corrected for the effects of variables that shift
the relationship between the partial pressure of oxygen (PO2) and saturation, such as: pH,
temperature, the partial pressure of carbon dioxide (PCO2), 2,3-DPG, and fetal hemoglobin.
In the case of SpCO, different results are also expected if concentration of methemoglobin in
the blood gas sample is abnormal (greater than 2% for methemoglobin concentration). High
levels of bilirubin may cause erroneous SpO2, SpMet, SpCO and SpHb readings. As blood
samples are usually taken over a period of 20 seconds (the time it takes to draw the blood)
a meaningful comparison can only be achieved if the oxygen saturation, carboxyhemoglobin
and methemoglobin concentration of the patient are stable and not changing over the period of
time that the blood gas sample is taken. Subsequently, blood gas and laboratory CO-Oximetry
measurements of SpO2, SpCO, SpMet, SpHb, SpOC and SpHct may vary with the rapid
administration of fluids and in procedures such as dialysis. Additionally, drawn, whole-blood
testing can be affected by sample handling methods and time elapsed between blood draw
and sample testing.
SIGNAL EXTRACTION TECHNOLOGY (SET)
Masimo Signal Extraction Technology's signal processing differs from that of
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 fi ltering. Adaptive
fi lters are powerful because they are able to adapt to the varying physiologic signals and/or
noise and 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®), in parallel with Fast Saturation Transform® (FST®), reliably identifi es the noise, isolates
it and, using adaptive fi lters, cancels it. It then reports the true arterial oxygen saturation for display
on the monitor.