The Bispectral Index in children: comparing isoflurane and halothane

Area of Science:

• Anesthesiology
• Neurophysiology

Background:

• The Bispectral Index (BIS) is calibrated for common anesthetics like isoflurane.
• Halothane, used in pediatric anesthesia, has unique receptor interactions and EEG effects.
• Limited data exist on BIS monitoring with halothane.

Purpose of the Study:

• To compare BIS values for halothane and isoflurane at equipotent concentrations (1 MAC).
• To evaluate BIS at awakening for both anesthetic agents.

Main Methods:

• A randomized trial involving 40 children (2-15 years) was conducted.
• Anesthesia was induced with sevoflurane or propofol, followed by halothane or isoflurane to 1 MAC.
• BIS was recorded at 1 MAC and at awakening; values were compared using a t-test.

Main Results:

• BIS values at 1 MAC were significantly higher for halothane (56.5 ± 8.1) than isoflurane (35.9 ± 8.5).
• No significant difference in BIS values was observed at awakening between halothane (81.1 ± 11.9) and isoflurane (82.5 ± 16.4).

Conclusions:

• Halothane yields higher BIS values than isoflurane at equipotent concentrations.
• BIS values at awakening are equivalent for both agents.
• BIS monitoring requires careful interpretation when using halothane due to concentration-dependent effects.