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Published on: June 3, 2021
Bispectral index profile during carotid cross clamping
Vincent Bonhomme1, Quentin Desiron, Thierry Lemineur
1University Department of Anesthesia and Intensive Care Medicine, CHR de la Citadelle, Liege, Belgium. vincent.bonhomme@chu.ulg.ac.be
Journal of Neurosurgical Anesthesiology
|January 2, 2007
Summary
During carotid cross clamping (CXC) under anesthesia, the Bispectral Index (BIS) can paradoxically increase, decrease, or stay stable. BIS changes may indicate borderline ischemia or nociceptive stimulation, requiring careful interpretation.
Area of Science:
- Neuroscience
- Anesthesiology
- Critical Care Medicine
Background:
- Carotid endarterectomy requires careful anesthetic management to maintain cerebral perfusion.
- The Bispectral Index (BIS) is used to monitor anesthetic depth, but its behavior during carotid cross clamping (CXC) is not fully understood.
Purpose of the Study:
- To investigate the Bispectral Index (BIS) profile during carotid cross clamping (CXC) in patients undergoing carotid endarterectomy.
- To correlate BIS changes with electroencephalogram (EEG) parameters and internal carotid artery (ICA) backflow.
Main Methods:
- A pilot study and a main study group of patients undergoing carotid endarterectomy under total intravenous anesthesia were included.
- Propofol and remifentanil infusions were kept constant to maintain BIS between 40-60.
- BIS, A-Line Autoregressive Index (AAI), and processed EEG parameters were recorded before, during, and after CXC.
- Internal carotid backflow was graded as good, moderate, or poor.
Main Results:
- During the first 3 minutes after CXC, BIS increased (>60) in 47%, decreased (<40) in 25%, and remained stable (40-60) in 28% of patients.
- BIS increase was more frequent in patients with moderate or poor ICA backflow.
- BIS changes correlated with AAI, EEG amplitude, EEG suppression ratio, and time from anesthesia induction to CXC.
Conclusions:
- The Bispectral Index (BIS) exhibits variable behavior during carotid cross clamping (CXC) under stable anesthesia.
- Paradoxical BIS increases may relate to borderline cerebral ischemia, altered anesthetic concentration, or nociceptive stimulation.
- Clinicians should exercise caution when interpreting BIS values during CXC due to these potential confounding factors.
