User's Manual

4-8 Radical-7R Pulse CO-Oximeter Operator’s Manual
4
NUMERIC DISPLAY - (PI)
The perfusion index (PI) display provides a relative numeric indication of the pulse strength at
the monitoring site. It is a calculated percentage of the pulsatile signal to non-pulsatile signal
of arterial blood moving through the site. PI may be used to find the best perfused site and to
monitor physiological changes in the patient. It displays an operating range of 0.01 percent
to 20.00 percent. A percentage greater than 1.00 percent is desired. Extreme changes in the
display number are due to motion artifact and changes in physiology and blood flow. The PI
measurement is displayed as follows:
≤ 0.99 (2 decimal places)
1.0 to 9.9 (1 decimal place)
≥10 (0 decimal places)
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%).
LOW PERFUSION
The Radical-7R Pulse CO-Oximeter displays a “Low PI” message when there are very low
amplitude arterial pulsations.
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 PI 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
ACTIONS TO BE TAKEN
If the SpO
2
, SpCO, SpMet, SpHb, SpOC, SpHct, PVI, PI or pulse rate readings show significant
differences, do the following:
■ Make sure the emitter and detector are aligned directly opposite each other.
■ Select a site where the distance between the emitter and detector is minimized.
■ 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 to increase perfusion. However, 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 these solutions are not possible, operate the Pulse CO-Oximeter on
battery power, or try plugging the Pulse CO-Oximeter into a different electrical outlet.
■ 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 or low strobing
light. Although the Radical-7R with integrated Masimo Rainbow SET technology has
Operation