H100B Pulse Oximeter User Manual
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7.3 Measured Versus Calculated
Saturation
When saturation is calculated from a blood gas partial
pressure of oxygen (PO
2
), the calculated value may
differ from the SpO
2
measurement of a pulse oximeter.
This usually occurs because the calculated saturation
was not appropriately corrected for the effects of
variables that shift the relationship between PO
2
and pH,
the partial pressure of carbon dioxide (PCO
2
), 2,3-DPG,
and fetal hemoglobin.
