Effects of Deep Hypothermic Circulatory Arrest With Retrograde Cerebral Perfusion on Electroencephalographic Bispectral Index and Suppression Ratio

Intraoperative Electroencephalogram Suppression Predicts Postoperative Delirium

“…9 EEG suppression does not occur during physiological sleep, and it typically reflects pathology, unless deep general anesthesia or severe hypothermia are present. [10][11] EEG suppression in other settings has been associated with poor outcomes, including six-month mortality in mechanically ventilated ICU patients, 12 worse neurologic outcome following therapeutic hypothermia for ventricular fibrillation, 13 and increased incidence of post-coma delirium in ICU patients. 14 Prior studies have found a reduced incidence of delirium when anesthesia clinicians use a processed EEG monitor [15][16] or when they target a higher value of the processed EEG index, [17][18] but the single study 19 that directly identified a relationship between intraoperative EEG suppression and postoperative delirium was relatively small, and did not adjust for potential confounding variables.…”

Neuromonitoring in der Kardioanästhesie

“…Bei der Interpretation des prozessierten EEGs ist weiterhin zu beachten, dass es durch die Hypothermie während CPB beeinflusst wird: Bei der Mehrzahl der Patienten zeigt beispielsweise der Bispektrale Index (BIS) bei sinkender Körper-temperatur einen biphasischen Verlauf [52]. Im Temperaturbereich von 35 …”

“…Unterhalb einer Temperatur von ca. 28°C kommt es dann jedoch zu einem raschen Abfall des BIS, [52] der schließlich bei ungefähr 18°C -mit Einsetzen des isoelektrischen EEGs [56] -einen Wert von Null erreicht[52]. Von Patient zu Patient ist die Temperatur, bei der es zum Wechsel vom geringen zum raschen BIS-Abfall kommt (bzw.…”

Brain Monitoring With Electroencephalography and the Electroencephalogram-Derived Bispectral Index During Cardiac Surgery

“…96,97 The association may be linear, 97 or may be biphasic, with faster BIS decline at more extreme degrees of hypothermia. 96 It is important to mention that drug regimens in these studies were highly variable and might have influenced BIS changes during hypothermic conditions; the pharmacokinetics of volatile anesthetics 98 and propofol 99 are also affected by hypothermia. Typically, a persistently suppressed EEG (Figure 1) and a BIS number approaching 0 occur during periods of deep hypothermic arrest.…”