Comparison of Two Electroencephalogram (EEG)-Derived Indices With Electroencephalogram Signals

Comparison of Bispectral Index and Entropy With Electroencephalogram During Sevoflurane Anaesthesia

Bispectral Index (BIS) and Entropy indices will be compared with each other, and to raw EEG signals in patients receiving sevoflurane anaesthesia. BIS and Entropy numbers often differ significantly from each other during surgery, and the reason for this has not been studied in detail, therefore remaining only poorly understood. BIS and Entropy, together with multi-channel EEG, will be collected and analyzed later on. Course of anaesthesia and surgery will be annotated. All relevant information from anaesthesia monitor will be collected on computer.

Inclusion Criteria:

• Planned surgery necessitating general anaesthesia
• Expected duration of anaesthesia 30 min or more
• Need of endotracheal intubation
• ASA status 1, 2 or 3

Exclusion Criteria:

• Significant disorders of the autonomic or central nervous system
• Family history of malignant hyperthermia
• Clinical history of anaphylactic reaction against inhaled anaesthetics
• Disability to communicate with Finnish language