User's Manual

Radius-7 Chapter 1- Technology Overview
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The Radius-7 uses a multi-wavelength sensor to distinguish between oxygenated blood,
deoxygenated blood, blood with carbon monoxide, oxidized blood and blood plasma.
The Radius-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 Radius-7 for calculation.
1. Light Emitting Diodes (LEDs)
(7 + wavelengths)
2. Detector
Once the Radius-7 receives the signal from the sensor, it utilizes proprietary algorithms to
calculate the patient’s functional oxygen saturation (SpO
2
[%]), 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. The maximum
skin surface temperature is measured to be less than 41 º C (106º F) in a minimum 35 º C (95
º F) ambient. This is verified by Masimo sensor skin temperature test procedures.
General Description for Total Hemoglobin (SpHb)
Pulse CO-Oximetry is a continuous and non-invasive method of measuring the levels of total
hemoglobin (SpHb) in arterial blood. It relies on the same principles of pulse oximetry to
make its SpHb measurement.