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Operator's Manual English 71
4.13.1. About Area Under the Curve (AUC)
Figure 63. AUC SUMMARY Screen
1. Current AUC totals
2. Current baselines
3. AUC start time
4. RESET AUC (press to restart collection)
5. Current AUC threshold type (press to
change)
6. Current AUC threshold (press arrow
keys to change)
AUC (Area Under the Curve), also referred to as cumulative saturation below threshold,
quantifies the depth and duration of desaturation below a specific value.
AUC was originally a metric in The STS (Society of Thoracic Surgeons) Adult Cardiac Surgery
Database and Congenital Heart Surgery Database. High AUC calculated from a threshold of
25% below baseline rSO
2
has been found to correlate with increased morbidity.
By default, the monitoring system uses a threshold of 50 for AUC calculations. If desired,
you can change the AUC threshold to any value between 30 and 60, or you can specify a
percentage below baseline from 0% to 30%.
The monitoring system automatically calculates AUC by multiplying the difference
between the threshold and the current rSO
2
values times the duration that rSO
2
is below
the threshold. Units are minute-%. Values are accumulated throughout the case. The AUC
threshold applies to all sensors being monitored.
Note: If you retake baselines at any point while monitoring, the monitoring system does
not reset AUC data collection to zero. If desired, you can reset AUC data collection as
described in Resetting AUC Collection, page 72.
4.13.2. Changing the AUC Threshold
By default, rSO
2
values must fall below a fixed threshold of 50 to be included in AUC totals.
You can change this threshold any time after monitoring begins.
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