Measured Versus Calculated Saturation; Oxyhemoglobin Dissociation Curve - Nellcor N-200 Operator's Manual

Measured versus Calculated Saturation

When saturation is calculated from a blood gas partial pressure
of oxygen (PO
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
and saturation (Figure 1): pH, temperature, the partial
pressure of carbon dioxide (PCO
hemoglobin.
100
), the calculated value may differ from the SpO
2
pH
Temperature
PCO
2
2,3-DPG
Fetal Hb
50
0
Figure 1: Oxyhemoglobin Dissociation Curve
), 2,3-DPG, and fetal
2
pH
Temperature
PCO
2
2,3-DPG
50
PO (mmHg)
2
Principles of Operation
100
2
2
13