Electroencephalographic mapping during routine clinical practice: cortical arousal during tracheal intubation?

Area of Science:

• Anesthesiology
• Neuroscience
• Quantitative Electrophysiology

Background:

• Anesthesia aims to prevent patient awareness and response to noxious stimuli.
• Tracheal intubation is a potent noxious stimulus during surgical procedures.

Purpose of the Study:

• To quantitatively analyze electroencephalogram (EEG) changes during tracheal intubation.
• To assess the effectiveness of etomidate and sufentanil in blunting the EEG response to intubation.

Main Methods:

• Quantitative EEG analysis in 42 patients undergoing anesthesia with etomidate and sufentanil.
• EEG recorded from eight bipolar electrodes, Z-transformed for relative power in delta, theta, alpha, and beta bands.
• Correlation analysis between EEG changes and anesthetic drug doses.

Main Results:

• Tracheal intubation induced cortical arousal, evidenced by accelerated EEG frequencies across all bands.
• Alpha frequency band showed the most significant increase, particularly in fronto-temporal regions.
• Anesthetic doses correlated with EEG changes, but were insufficient to prevent arousal from intubation.

Conclusions:

• Standard clinical practice doses of etomidate and sufentanil do not fully suppress cortical arousal during tracheal intubation.
• The noxious stimulation of intubation can overcome the anesthetic effects, leading to a 'cortical wake-up' phenomenon.
• The clinical significance of this arousal phenomenon requires further investigation.