User's Manual

Radical-7 Chapter 1: Technology Overview
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Successful Monitoring for SpMet
A stable SpMet reading is associated with correct sensor placement, small physiological
changes during the measurement and acceptable levels of arterial perfusion in the patient’s
fingertip (measurement site).
Physiological changes at the measurement site are mainly caused by fluctuations in the
oxygen saturation, blood concentration and perfusion. See Safety Information, Warnings,
and Cautions on page 11.
SpCO, SpMet, and SpHb Measurements During Patient Motion
The Radical-7 displays measurements of SpCO, SpMet, and SpHb during patient motion.
However, because of the changes in the physiological parameters such as blood volume,
arterial-venous coupling, etc. that occur during patient motion, the accuracy of such
measurements may not be reliable during excessive motion. In this case, the measurement
value for SpCO, SpMet, or SpHb displays as dashes (---) and a message (Low SpCO SIQ, Low
SpMet SIQ, or Low SpHb SIQ) displays to alert the clinician that the instrument does not have
confidence in the value due to poor signal quality caused by excessive motion or other signal
interference.
rainbow Acoustic Monitoring (RAM) Technology
rainbow Acoustic Monitoring (RAM) continuously measures a patient’s respiration rate based
on airflow sounds generated in the upper airway. The Acoustic Sensor translates airflow
sounds generated in the upper airway to an electrical signal that can be processed to produce
a respiration rate, measured as breaths per minute.
Respiratory sounds include sounds related to respiration such as breath sounds (during
inspiration and expiration), adventitious sounds, cough sounds, snoring sounds, sneezing
sounds, and sounds from the respiratory muscles [1].
These respiratory sounds often have different characteristics depending on the location of
recording [2] and they originate in the large airways where air velocity and air turbulence
induce vibration in the airway wall. These vibrations are transmitted, for example, through
the lung tissue, thoracic wall and trachea to the surface where they may be heard with the aid
of a stethoscope, a microphone or more sophisticated devices.
rainbow Acoustic Monitoring Architecture
The following figure illustrates how a respiratory sound produced by a patient can be turned
into a numerical measurement that corresponds to a respiratory parameter.
Patient Sensor Acquisition
System
Respiratory airflow
to sound
Sound to electrical
signal
Electrical signal to digital
signal