Validation of the index of consciousness during sevoflurane and remifentanil anaesthesia: a comparison with the bispectral index and the cerebral state index

The three indices performed equally well during the induction phase and were able to predict the level of consciousness of the patients satisfactorily. During maintenance, the IoC and the BIS showed good agreement with the clinical signs. The CSI was significantly influenced by the administration of atracurium; therefore, the agreement with the OAAS scale during the maintenance phase was significantly less for CSI than for IoC and BIS.