Rad-8 Signal Extraction Pulse Oximeter Operator’s Manual
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o p e r a t i o n
LOW PERFUSION
The Rad-8 indicates perfusion on a 10-bar LED indicator. The lower two segments of the
bar will turn red when the amplitude of the arterial pulsations is very low (low perfusion).
It has been suggested that at extremely low perfusion levels, pulse oximeters can measure
peripheral saturation, which may differ from central arterial saturation
1
. This “localized
hypoxemia” may result from the metabolic demands of other tissues extracting oxygen
proximal to the monitoring site under conditions of sustained peripheral hypoperfusion.
(This may occur even with a pulse rate that correlates with the ECG heart rate.)
CAUTION:
IF THE LOW PERFUSION INDICATION IS FREQUENTLY DISPLAYED, FIND
A BETTER-PERFUSED MONITORING SITE. IN THE INTERIM, ASSESS THE PATIENT
AND, IF INDICATED, VERIFY OXYGENATION STATUS THROUGH OTHER MEANS.
1 Severinghaus JW, Spellman MJ. pulse oximeter Failure Thresholds in Hypotension and
Vasoconstriction. Anesthesiology 1990; 73:532-537
ACTIONS TO BE TAKEN
If the SpO
2
readings show significant differences, do the following:
■
Make sure the emitter and photodetector are aligned directly opposite each other.
■
Select a site where the distance between the emitter and photodetector is mini-
mized.
■
Wipe the sensor site with a 70% isopropyl alcohol pad or rubefacient cream (10-
30% methyl salicylate and 2-10% menthol) for 20-30 seconds. Strong vasodilator
creams, such as nitroglycerin paste, are not recommended.
■
If possible, remove electrical noise sources such as electrosurgical units or other
electrical/electronic equipment.
■
If artificial nails or excessive fingernail polish are present, select another site or
remove the polish/artificial nails.
■
If possible, ensure that the sensor is placed in a location with low ambient light.
Although the Rad-8 pulse oximeter integrated with Masimo SET technology has
significant immunity to ambient light, excessive ambient light may cause readings to
be incorrect.
CAUTION:
IF ANY MEASUREMENT SEEMS QUESTIONABLE, FIRST CHECK THE
PATIENT’S VITAL SIGNS BY ALTERNATE MEANS AND THEN CHECK THE PULSE
OXIMETER FOR PROPER FUNCTIONING.
SIGNAL IQ AND PULSE BAR
The Rad-8 display provides a visual indicator of the plethysmogram signal quality and
an alert when the displayed SpO
2
values are not based on adequate signal quality. The
signal quality indicator displayed on the Rad-8 is called the Signal IQ. The Signal IQ can
be used to identify the occurrence of a patient’s pulse and the associated signal quality of
the measurement.
The Signal IQ is shown as a “bouncing bar” indicator, where the peak of the bar coincides
with the peak of an arterial pulsation. Even with a plethysmographic waveform obscured by
artifact, the Rad-8 locates the arterial pulsation. The pulse tone (when enabled) coincides
with the peak of the Signal IQ bar. As saturation increases or decreases, the pulse tone will
ascend or descend accordingly, for each 1% change in saturation.
The height of the Signal IQ bar indicates the quality of the measured signal. A high verti-
cal bar indicates that the SpO
2
measurement is based on a good quality signal. A small
vertical bar indicates that the SpO
2
measurement is based on data with low signal quality.
When the signal quality is very low the accuracy of the SpO
2
measurement may be com-
promised. A “Low Signal IQ” is indicated by a bar height of two bars or less and the bars
turn red. When this occurs, proceed with caution and do the following:
■
Assess the patient.
■
Check the sensor and ensure proper sensor application. The sensor must be well
secured to the site for the Rad-8 to maintain accurate readings. Also, misalignment
of the sensor’s emitter and detector can result in smaller signals.
■
Determine if an extreme change in the patient’s physiology and blood flow at the
monitoring site occurred, (e.g. an inflated blood pressure cuff, a squeezing motion,
sampling of an arterial blood specimen from the hand containing the pulse oximetry
sensor, severe hypotension, peripheral vasoconstriction in response to hypothermia,
medications, or a spell of Raynaud’s syndrome.)
■
With neonates or infants, check that the peripheral blood flow to the sensor site is
not interrupted. Interruption, for example, as may occur while lifting or crossing their
legs, during a diaper change.
After performing the above, if the “Low Signal IQ” indication occurs frequently or continu-
ously, obtaining an arterial blood specimen for CO-Oximetry analysis may be considered
to verify the oxygen saturation value.
o p e r a t i o n
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Rad-8 Signal Extraction Pulse Oximeter Operator’s Manual
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