User's Manual

Rad-87 Pulse CO-Oximeter Operator’s Manual
1-7
1
Overview
Functional Saturation
The Rad-87 is calibrated to measure and display functional saturation (SpO
2
): the amount of
oxyhemoglobin expressed as a percentage of the hemoglobin that is available to transport oxygen.
Rad-87 vs. Drawn Whole Blood Measurements
When SpO
2
, SpCO, SpMet and SpHb measurements obtained from the Rad-87 (noninvasive)
are compared to drawn whole blood (invasive) measurements by blood gas and/or laboratory
CO-Oximetry methods, caution should be taken when evaluating and interpreting the results.
The blood gas and/or laboratory CO-Oximetry measurements may differ from the SpO
2
, SpCO,
SpMet and SpHb measurements of the Rad-87 Pulse CO-Oximeter. In the case of SpO
2
, different
results are usually obtained from the arterial blood gas sample if the calculated measurement
is not appropriately corrected for the effects of variables that shift the relationship between the
partial pressure of oxygen (PO2) and saturation, such as: pH, temperature, the partial pressure
of carbon dioxide (PCO2), 2,3-DPG, and fetal hemoglobin. In the case of SpCO, different results
are also expected if concentration of methemoglobin in the blood gas sample is elevated. High
levels of bilirubin may cause erroneous SpO
2
, SpMet, SpCO and SpHb readings. As blood
samples are usually taken over a period of 20 seconds (the time it takes to draw the blood)
a meaningful comparison can only be achieved if the oxygen saturation, carboxyhemoglobin
and methemoglobin concentration of the patient are stable and not changing over the period of
time that the blood gas sample is taken. Subsequently, blood gas and laboratory CO-Oximetry
measurements of SpO
2
, SpCO, SpMet and SpHb may vary with the rapid administration of fluids
and in procedures such as dialysis. Additionally, drawn, whole-blood testing can be affected by
sample handling methods and time elapsed between blood draw and sample testing.
Masimo SET Signal Extraction Technology for SpO
2
Measurements
Masimo Signal Extraction Technology’s signal processing differs from conventional pulse
oximeters. Conventional pulse oximeters assume that arterial blood is the only blood moving
(pulsating) in the measurement site. During patient motion, however, the venous blood also
moves, causing conventional pulse oximeters to read low values, because they cannot distinguish
between the arterial and venous blood movement (sometimes referred to as noise). Masimo SET
pulse oximetry utilizes parallel engines and adaptive digital filtering. Adaptive filters are powerful
because they are able to adapt to the varying physiologic signals and/or noise and separate them
by looking at the whole signal and breaking it down to its fundamental components. The Masimo
SET signal processing algorithm, Discrete Saturation Transform
®
(DST
®
) reliably identifies the
noise, isolates it and, using adaptive filters, cancels it. It then reports the true arterial oxygen
saturation for display on the monitor.
SpMet, SpCO, and SpHb Measurements During Patient Motion
The Rad-87 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. When the Rad-87 does not have confidence in the value of a
parameter due to poor signal quality caused by excessive motion or other signal interference, the
measurement for the parameter will alternate with "---".