User's Manual

Radical-7 Chapter 1: Technology Overview
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The Radical-7 uses a multi-wavelength sensor to distinguish between oxygenated blood,
deoxygenated blood, blood with carbon monoxide, oxidized blood and blood plasma.
The Radical-7 utilizes a sensor with various light-emitting diodes (LEDs) that pass light
through the site to a diode (detector). Signal data is obtained by passing various visible and
infrared lights (LEDs, 500 to 1400nm) 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 to 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 Radical-7 for calculation.
1. Light Emitting Diodes (LEDs)
(7 + wavelengths)
2. Detector
Once the Radical-7 receives the signal from the sensor, it utilizes proprietary algorithms to
calculate the patient’s functional oxygen saturation (SpO2 [%]), blood levels of
carboxyhemoglobin (SpCO [%]), methemoglobin (SpMet [%]), total hemoglobin
concentration (SpHb [g/dL]) and pulse rate (BPM). The SpCO, SpMet and SpHb
measurements rely on a multi-wavelength 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), verified by Masimo sensor skin temperature
test procedure.
Pulse CO-Oximetry vs. Drawn Whole Blood Measurements
When SpO2, SpCO, SpMet, and SpHb measurements obtained from the Radical-7
(noninvasive) 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, and SpOC measurements of the Radical-7. Any comparisons should be
simultaneous, meaning the measurement on the device should be noted at the exact time
that blood is drawn.
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 (PO
2
) 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, and SpOC may