BIS guide for clinicians

The Evolving Role of Brain Function Monitoring
The Evolving Role of Brain
Function Monitoring
Despite remarkable improvements in the assessment of the
cardiovascular and respiratory systems during anesthesia,
determination of the effect of anesthetic agents on the central
nervous system had remained a challenge. Now, technologies
that permit routine neurophysiologic monitoring of the
central nervous system provide a direct measure of anesthetic
effect during anesthesia. 52 Combining brain function
monitoring with traditional monitoring and assessment of
clinical signs, can provide the anesthesia professional a more
complete approach to optimizing the selection and/or dosing
of anesthetic and adjuvant agents for each patient.
Concerns regarding the consequences of both inadequate
and excessive anesthetic effect have increased in the last few
years. As noted previously, inadequate anesthetic effect is
the primary etiology of unintentional intraoperative
awareness. 41 This adverse event was discussed in detail in
the previous section.
Excessive anesthetic effect also has consequences. In some
situations, excessive anesthetic effect may result in
cardiovascular depression, and very rarely, cardiac arrest. 53
More recently, new concerns about other consequences of
excessive anesthetic effect have appeared. Exposure to high
doses of volatile anesthetic is a risk for acute transient
epileptiform changes in the EEG. 54 In addition, excessive
anesthetic effect has been associated with adverse long-term
55, 56
outcome.
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