User's Manual

Radical-7 Chapter 1: Technology Overview
www.masimo.com 25 Masimo
Functional Oxygen Saturation
The Radical-7 is calibrated to measure and display functional oxygen 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.
General Description for Pulse Rate (BPM)
Pulse rate, measured in beats per minute (BPM) is based on the optical detection of
peripheral flow pulse.
General Description for Perfusion Index (PI)
The Perfusion Index (PI) is the ratio of the pulsatile blood flow to the non-pulsatile or static
blood in peripheral tissue. PI thus represents a noninvasive measure of peripheral perfusion
that can be continuously and noninvasively obtained from a pulse oximeter.
General Description for Pleth Variability Index (PVI)
The pleth variability index (PVI) is a measure of the dynamic changes in the perfusion index
(PI) that occur during the respiratory cycle. The calculation is accomplished by measuring
changes in PI over a time interval where one or more complete respiratory cycles have
occurred. PVI is displayed as a percentage (0-100%).
The utility of PVI is unknown at this time and requires further clinical studies. Technical
factors that may affect PVI include probe malposition and patient motion.