Masimo Rad-87, Operator'S Manual

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Rad-87 Pulse CO-Oximeter Operator’s Manual 4-7 4-7
4
o p e r a t i o n
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 PVI bar graph is a representation of the calculated value. The lower the height of the
bar, the less variability there is in the PI over a respiratory cycle. Press the Display key
to toggle to the PVI numeric measurement.
LOW PERFUSION - (SIQ)
The Rad-87 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
3 . 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 MESSAGE IS FREQUENTLY DISPLAYED, FIND A
BETTER-PERFUSED MONITORING SITE. IN THE INTERIM, ASSESS THE
PATIENT AND, IF INDICATED, VERIFY OXYGENATION STATUS THROUGH
OTHER MEANS.
3
Severinghaus JW, Spellman MJ. Pulse Oximeter Failure Thresholds in Hypotension and Vasoconstriction.
Anesthesiology 1990; 73:532-537
SIGNAL IQ
The Rad-87 Pulse CO-Oximeter display provides a visual indicator of signal quality and
an alert when the displayed SpO2 values are not based on adequate signal quality. The
signal quality indicator displayed on the Rad-87 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 represented as a bar indicator where the height of the bar coincides with
the strength of an arterial pulsation. Even with a plethysmographic waveform obscured by
artifact, the Rad-87 locates the arterial pulsation. The pulse tone (when enabled) coincides
with the rise of the Signal IQ Index.
The height of the Signal IQ Index indicates the quality of the measured signal. A high Signal
IQ Index indicates that the SpO2 measurement is based on a good quality signal. A small
Signal IQ Index indicates that the SpO2 measurement is based on data with low signal
quality. When the signal quality is very low, the accuracy of the SpO2 measurement may
be compromised. When the Signal IQ is low and the bar turns red, 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-87 to maintain accurate readings. Also, misalignment
of the sensor’s emitter and detector can result in smaller signals.