The intraoperative combination of neuroendocrine tumor (NET)–induced hypertensive crisis and massive hemorrhage represents one of anesthesia’s greatest physiologic challenges.
Traditional monitors describe hemodynamics, but EEG-derived monitoring (BIS and DSA) allows anesthesiologists to “see” the brain’s response to circulatory and anesthetic forces in real time.
This case illustrates how BIS with Density Spectral Array (DSA) can:
Differentiate peripheral catecholamine-driven hypertension from inadequate anesthesia, and
Detect cerebral hypoperfusion and reperfusion after hemorrhagic shock.
1. Initial Blue Areas (Left of Display)
Low EEG power (blue-green bands, 13–25 Hz range).
Represents transient cortical desynchronization — typically seen:
Shortly after anesthetic equilibration,
During airway or surgical stimulation,
Or as a brief EMG interference episode.
Not a sign of awareness but rather an unstable transition before synchronized alpha-theta waves dominate.
2. Red Alpha–Theta Plateau (Right of Display)
Dense red-orange color between 8–12 Hz.
Stable cortical synchronization (deep, steady anesthesia).
SEF 11 Hz and BIS 38 confirm adequate hypnosis.
Interpretation:
The initial blue areas show transient cortical instability, but once sevoflurane equilibrates, the DSA stabilizes — confirming cortical calm despite peripheral hypertension.
Interpretive Pearl:
Early blue zones = cortical adjustment; stable red alpha–theta = anesthetic equilibrium.
Interpretive Pearl:
The blue DSA areas here signify global cortical hypoperfusion, not anesthetic overdose.
Their gradual replacement by red hues reflects successful brain reperfusion after shock.
Cerebral color coding for anesthesiologists:
Blue: brain starving
Red: brain perfused
Yellow–orange: transition and metabolic recovery
After hemostasis and transfusion, the patient stabilized with MAP 70 mmHg and normothermia.
Postoperative ICU course was uneventful; she was extubated 24 hours later with GCS 15/15 and no neurological deficits, confirming that EEG-guided anesthetic titration protected cerebral function despite extreme hemodynamic swings.
