Depth of anaesthesia monitors – Bispectral Index (BIS), E-Entropy and Narcotrend-Compact M

2.1 The BIS monitor (Covidien), E-Entropy monitor (GE Healthcare) and Narcotrend-Compact M monitor (MT MonitorTechnik) are EEG-based monitors that are used in combination with standard clinical monitoring and clinical skills to indicate the patient's response to anaesthetic drugs (hereafter referred to as depth of anaesthesia) during surgery.

2.2 Other manufacturers have licensed the BIS (or BISx) technology from Covidien in order to produce BIS modules that are compatible with their own anaesthesia systems.