Measured Versus Calculated Saturation; Data Update Period, Data Averaging, And Signal Processing; Figure 10-1. Oxyhemoglobin Dissociation Curve - Covidien Nellcor Operator's Manual

Theory of Operations

Measured versus Calculated Saturation

10.5.2
When calculating saturation from a blood gas partial pressure of oxygen (PO2),
the calculated value may differ from the SpO
system. This usually occurs when saturation calculations exclude corrections
for the effects of variables such as pH, temperature, the partial pressure of
carbon dioxide (PCO2), and 2,3-DPG, that shift the relationship between PO2
and SpO
10.5.3
1 % Saturation Axis
2 PO2 (mmHg) Axis

Data Update Period, Data Averaging, and Signal Processing

10.5.4
The advanced signal processing of the OxiMax™ algorithm automatically extends
the amount of data required for measuring SpO
measurement conditions. The OxiMax™ algorithm automatically extends the
dynamic averaging time required beyond seven (7) seconds during degraded or dif-
ficult measurement conditions caused by low perfusion, signal artifact, ambient
light, electrocautery, other interference, or a combination of these factors, which
84
.
2
Figure 10-1. Oxyhemoglobin Dissociation Curve
3 Increased pH; Decreased temperature, PCO2, and 2,3-DPG
4 Decreased pH; Increased temperature, PCO2, and 2,3-DPG
measurement of a monitoring
2
and pulse rate depending on the
2
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