Operator's Manual

The BIS™ Advance Parameters
BIS™ Advance Monitor
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Table 1. The BIS™ Advance Monitor Parameters
Processed Parameter Description
Bispectral Index (BIS™
number)
The BIS™ number is a processed EEG value
representing the depth of sedation.
It is a continuously processed EEG parameter that
correlates to the patient's level of hypnosis, where
100 = awake and 0 = flat line EEG. BIS™ was
designed to correlate with "hypnotic" clinical
endpoints and to track changes in the effects of
anesthetics of the brain.
This value is computed based on computations on
the acquired 2 or 4 EEG channels. For the standard
system with 2-channel sensors, the system shall
produce one BIS™ value; for 4-channel sensors, the
system shall produce 2 BIS™ values, one for each
brain hemisphere. The EEG number of channels
feature enables the user to view the primary
measured electrodes of each brain hemisphere,
only one brain hemisphere, or all of them.
A BIS™ value above 90 typically represents an
awake state. As the drugs cause deeper sedation,
this value will decrease. You can set the BIS™ value
limits to cause an alarm if the level of
consciousness exceeds the desired limits.
A BIS™ value below 60 indicates a high probability
of drug-induced unconsciousness.
A BIS™ value below 30 indicates an increasing level
of EEG suppression.
Both the BIS™ number and the BIS™ trend are
displayed on the Home screen. For more details,
reference 3.7 Home Screen on page 88.
BIS™ Smoothing Rate
Smoothing rate is the time over which the BIS™
value is averaged. The smoothing rate can be
adjusted by the user; for the Extend sensor it is
automatically 30 seconds. A shorter smoothing
rate provides increased responsiveness to state
changes, such as induction or awakening. A longer