User's Manual

Radical-7 Chapter 1: Technology Overview
www.masimo.com 26 Masimo
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 (PR). 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