Anesthetic-state determing

A monitor for determining anesthetic state of a subject, the monitor being for use with a stimulator for applying a non-surgical perturbation stimulus to a patient and providing indicia of intensity of the applied stimulus, the monitor comprising:

• a sensor adapted to couple to the patient and to sense at least one bodily parameter that is at least partially indicative of anesthetic state, and to provide a sensor output indicative of the sensed at least one bodily parameter;
• an input configured to couple to the stimulator to receive the indicia of timing and intensity of the applied stimulus;
• and
• an analyzer coupled to the sensor and the input and configured to process the sensor output and the indicia of intensity of the applied stimulus to determine a comparison between (1) the sensor output without the perturbation and the sensor output when the subject responds to the perturbation and (2) the applied stimulus during a time other than when the perturbation is applied and the applied stimulus during application of the perturbation.

A method of determining anesthetic state of a patient prior to performing a procedure on the patient, the method comprising:

• sensing at least one bodily parameter of the patient that is at least partially indicative of anesthetic state;
• providing a sensed signal indicative of the sensed at least one bodily parameter;
• applying a stimulus perturbation to the patient, the stimulus perturbation being different from the procedure;
• analyzing the sensed signal from a first time when the patient is reacting to the stimulus perturbation and from a second time other than the when the patient is reacting to the stimulus perturbation;
• and
• analyzing a first intensity of the stimulus perturbation and a second intensity of a stimulus, if any, provided to the patient during the second time.