This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Morimoto, Y. Articles by Sakabe, T. Search for Related Content PubMed PubMed Citation Articles by Morimoto, Y. Articles by Sakabe, T. Related Collections Monitoring (Non-cardiac) Technology Pharmacology

---

TECHNOLOGY, COMPUTING, AND SIMULATION

Changes in Electroencephalographic Bicoherence During Sevoflurane Anesthesia Combined with Intravenous Fentanyl

From the Department of Anesthesiology-Resuscitology, Yamaguchi University School of Medicine, Yamaguchi, Japan; and *Department of Anesthesiology, Osaka University Graduate School of Medicine.

With the introduction of bispectral index (BIS) as a measure of a patient’s sedation during general anesthesia, attention has been directed toward bispectral analysis of electroencephalography (EEG). In the present study we evaluated the relationship between EEG bicoherence and sevoflurane concentration. Sixteen ASA physical status I–II patients scheduled for elective abdominal surgery were enrolled in the study. Anesthesia was induced with 5% sevoflurane and maintained with sevoflurane and oxygen (50%). Just before surgery, IV fentanyl (2 µg/kg) was given and then continuously infused (2 µg · kg^–1 · h^–1). Using software we developed, EEG bicoherence, BIS, and 95% spectral edge frequency (SEF95) were recorded at end-tidal sevoflurane concentrations of 0.5%, 0.8%, 1.1%, 1.4%, 1.7%, 2.0%, and 2.3%. Under light anesthesia, EEG bicoherence values were low. With increasing sevoflurane concentrations, 2 peaks of bicoherence emerged along the diagonal line (f1 = f2). Both the first (at around 4 Hz) and second (at around 10 Hz) grew higher (37.7% ± 7.5% and 35.1% ± 9.0%, respectively) as the sevoflurane concentration increased to 1.4%. However, the first peak leveled off whereas the second tended to decrease slightly with further increases in sevoflurane concentration. The BIS value decreased as the sevoflurane concentration increased and leveled off at 1.4% and higher concentrations of sevoflurane. The SEF 95 also decreased as the sevoflurane concentration increased up to 2.3%. Thus the distribution pattern of the two bicoherence peaks is likely to be better than BIS of the anesthetic effect of sevoflurane during surgery.

This article has been cited by other articles:

				K. Hayashi, M. Fujikawa, and T. Sawa Hyperventilation-induced hypocapnia changes the pattern of electroencephalographic bicoherence growth during sevoflurane anaesthesia Br. J. Anaesth., November 1, 2008; 101(5): 666 - 672. [Abstract] [Full Text] [PDF]