BIS guide for clinicians

Clinical Management
Clinical Management: Responding
to Sudden BIS Changes
When BIS monitoring is used during anesthesia care,
fluctuations in BIS values will likely be noted. Such
variability, like a single fluctuation in blood pressure, is not
necessarily clinically significant. However, specific
consideration should be given to sudden BIS changes or
situations where BIS seems inappropriately high or low.
For example, changes in the hypnotic state due to changes
in dose and/or patterns of agent delivery will produce
changes in the BIS value. Normally, if the change in
anesthetic dosing was incremental – e.g., slight adjustment
in the vaporizer setting – subsequent changes in BIS values
would be gradual. In contrast, a sudden dramatic change
would be unexpected and additional assessment would be
appropriate.
Tables 4 and 5 present an assessment process for sudden
increases or decreases in the BIS value.
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