Patent ID: 7215994

Claim:
A method for monitoring a state of anesthesia or sedation resulting from the administration of one or more drugs to a patient, the drug or drugs inducing the state of anesthesia or sedation by altering the state or functioning of one or both of the cortex of the brain or the sub-cortical components of the nervous system, the method comprising the steps of: (a) obtaining cortex-related EEG biopotential signal data from the patient; (b) obtaining subcortex-related biosignal data from the patient, the subcortex-related biosignal data including at least bioimpedance signal data; (c) calculating a first indicator comprising a measure of the complexity of the EEG biopotential signal data, the first indicator being indicative of cortical activity in the patient; (d) based on the subcortex-related biosignal data, calculating a set of indicators indicative of subcortical activity in the patient, the set of indicators including at least a second indicator calculated based on the bioimpedance signal data; and (e) producing a composite indication based on the first indicator and on the set of indicators.