Mindray BeneView T8, Operation Manual

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Monitoring BIS
16-3
16.3 Understanding the BIS Display
The BIS module provides with the monitor an EEG wave and the following numerics:
1. Bispectral Index (BIS)
The BIS numeric reflects the patient’s level of consciousness. It ranges from 100 for
wide awake to 0 in the absence of brain activity.
BIS numeric Description
100 The patient is widely awake.
70 The patient is underdosed but still unlikely to become aware.
60 The patient is under general anesthesia and loses consciousness.
40 The patient is overdosed and in deep hypnosis.
0 The EEG waveform is displayed as a flat line, and the patient has no
electrical brain activity.
2. Electromyograph (EMG)
EMG bar graph reflects the electrical power of muscle activity and high frequency
artifacts. The minimum possible EMG is about 25 dB.
‹
EMG
＜
55 dB: this is an acceptable ECG.
‹ EMG ≤ 30 dB: this is an optimal EMG.
3. Suppression Ratio (SR)
SR numeric is the percentage of time over the last 63-second period during which the
EEG is considered to be in a suppressed state.
4. Spectral Edge Frequency (SEF)
The SEF is a frequency below which 95% of the total power is measured.
5. Signal Quality Index (SQI)
The SQI numeric reflects signal quality and provides information about the reliability of
the BIS, SEF, TP, and SR and numerics during the last minute. It ranges from 0-100%:
‹
0 to 15%: the numerics cannot be derived.
‹ 15% to 50%: the numerics cannot be reliably derived.
‹
50% to 100%: the numerics are reliable.
6. Total Power (TP)
TP numeric indicates the power in the frequency band 0.5-30Hz. The useful range is
30-100db.