Covidien Nellcor GR101704, Service Manual

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Unique Technologies
Service Manual 3-5
Figure 3-2. Oxyhemoglobin Dissociation Curve
3.6.3
Data Update Period, Data Averaging, and Signal Processing
The advanced signal processing of the OxiMax™ algorithm automatically extends
the amount of data required for measuring SpO
2
and pulse rate depending on the
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
results in an increase in the dynamic averaging. If the resulting dynamic averaging
time exceeds 20 seconds for SpO
2
, the monitoring system displays the pulse search
indicator while continuing to update SpO
2
and pulse rate values every second. If
the dynamic averaging time exceeds 25 seconds, a low-priority Extended Update
alarm also appears.
As such measurement conditions extend, the amount of data required may
continue to increase. If the dynamic averaging time reaches 40 seconds, and/
or 50 seconds for pulse rate, a high priority alarm state results: the monitoring
1 % Saturation Axis 3 Increased pH; Decreased temperature, PCO2, and 2,3-DPG
2 PO2 (mmHg) Axis 4 Decreased pH; Increased temperature, PCO2, and 2,3-DPG