Operator's Manual

Radical-7 Chapter 1: Technology Overview
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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 (pO
2
) and saturation, such as:
pH,temperature, the partial pressure of carbon dioxide (pCO
2
), 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 abnormal (greater than 2% for
methemoglobin concentration).
In the case of SpHb, variation in hemoglobin measurements may be
profound and may be affected by sampling technique as well as the
patient's physiological conditions. Any results exhibiting inconsistency
with the patient's clinical status should be repeated and/or supplemented
with additional test data. As with most hemoglobin tests, a laboratory
blood sample should be analyzed prior to clinical decision making.
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, SpHb, and SpOC 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.
Measurements with Low Signal IQ should not be compared to laboratory
measurements.