GE Dash 3000, Operator'S Manual

Page: 190 / 270

18-6 Dash™ 3000/4000/5000 2000966-386D
Monitoring Bispectral Index (BIS)
potential. To temporarily stop the continuous lead detect signal, select the BIS
parameter window label > BIS SETUP > LEAD DETECT > OFF .
Disabling the Waveform Filter
The monitor uses an EEG filter to modify the raw EEG waveform with a combination
of low pass, high pass and notch filters. This produces waveform data display
between 2 and 70 Hz. To temporarily remove filters and display only the raw
waveform for troubleshooting purposes, select the
BIS parameter window label >
BIS SETUP > EEG FILTER > OFF . When the filter is removed, the waveform data
between 0.25 and 100 Hz displays.
Testing the BIS
BISx uses an internal DSC to filter and transmit data to the monitor. To test the
function of the DSC, select the
BIS parameter window label > BIS SETUP > BIS
TEST > ON . The message “ BIS TEST IN PROGRESS ” displays until the evaluation
is complete.
A “ PASS ” message displays if BISx is functioning within normal operating
parameters.
A “ FAIL ” message displays if BISx did not meet the noise, gain, high and low pass
normal values. If BISx fails, contact service.
Understanding Displayed Values
BIS
BIS is a processed EEG parameter which corresponds to the patient’s level of
consciousness. The resulting BIS values range from 100 (patient is wide awake) to 0.
Since BIS is an absolute value, baseline information about the patient is not required
for monitoring patients.
BIS Value Patient State
100 Patient is awake; responds to normal voice.
80 Patient is moderately sedated; responds to loud commands
or mild prodding/shaking.
60 Patient is in deep sedation; low probability of explicit recall
and unresponsive to verbal stimulus.
20 Patient is in deep sedation; burst suppression.
0 No brain activity detected.