Effect of landiolol on bispectral index and spectral entropy responses to tracheal intubation during propofol anaesthesia.

Author(s): Kawaguchi M, Takamatsu I, Masui K, Kazama T

Affiliation(s): Department of Anesthesiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.

Publication date & source: 2008-08, Br J Anaesth., 101(2):273-8. Epub 2008 Jun 9.

Publication type: Randomized Controlled Trial; Research Support, Non-U.S. Gov't

BACKGROUND: beta1-Adrenoceptor antagonists suppress the haemodynamic and arousal responses to tracheal intubation. The Entropy Module shows two spectral entropy-based indices, response entropy (RE) and state entropy (SE). The difference between RE and SE (RE-SE) may reflect nociception during general anaesthesia. In the present study, we investigated the effect of landiolol on entropy indices in response to tracheal intubation. METHODS: A total of 60 patients were randomly assigned to receive saline (Group S), remifentanil (Group R), or landiolol (Group L). Anaesthesia was induced by propofol target-controlled infusion. Two minutes after the induction of anaesthesia, infusion with vecuronium bromide and remifentanil, landiolol, or saline was initiated. Tracheal intubation was performed 7 min after anaesthesia induction. Arterial pressure, heart rate (HR), bispectral index (BIS), and entropy indices were recorded. RESULTS: In Group S, RE increased significantly after tracheal intubation, but there was no significant increase in BIS or SE. These increases in RE were abolished in Groups R and L. RE-SE increased significantly after tracheal intubation in Group S, whereas no increase in RE-SE was observed in Groups R and L. Increases in mean arterial pressure and HR after tracheal intubation were suppressed in Groups R and L compared with Group S. CONCLUSIONS: RE increased in response to tracheal intubation, whereas BIS and SE did not. Landiolol and remifentanil suppressed the increase in RE after tracheal intubation with significant inhibition of RE-SE difference.