System and Method for Guidance of Anesthesia, Analgesia and Amnesia

Abstract

A method for monitoring anesthetization of a patient, includes the steps of removably connecting a plurality of electrodes to the scalp of the patient and administering sufficient anesthesia to the patient so that the patient attains a plane of anesthesia selected by an operator. The brain waves of the patient are then amplified and digitized after the patient has been anesthetized, before beginning the medical procedure, to obtain a first set of digital data. The brain waves of the patient are then amplified and digitized during the medical procedure to provide a second set of digital data and the first and second sets of digital data are analyzed in at least one of a time domain and a frequency domain. Separate trajectories are then computed from the data analysis trajectories for at least two different indices of an anesthetic state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI). A system for providing anesthesia to a patient, includes a plurality of electrodes, a first arrangement allowing an operator to administer anesthesia to the patient until the patient has attained a selected plane of anesthesia and a second arrangement coupled to the electrodes for amplifying and digitizing brain waves of the patient after the patient has been anesthetized, before the medical procedure has been begun to obtain a first set of digital data, the second arrangement amplifying and digitizing ongoing brain waves of the patient during the medical procedure to provide a second set of digital data in combination with a third arrangement analyzing the first and second sets of digital data in at least one of a time domain and a frequency domain, a fourth arrangement computing from the data analysis separate trajectories for at least two different indices of a state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI), a fifth arrangement providing control signals when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia and a sixth arrangement automatically adjusting two different anesthetic agents administered to the patient based on the control signal to restore the patient to the selected plane of anesthesia.

1 .- 30 . (canceled) 
     
     
         31 . A method, comprising:
 administering to a patient a first interventional agent until the patient attains a first desired level of sensitivity to pain;   amplifying and digitizing brain waves of the patient before and at a first time after the administering step to generate a first set of digital data;   amplifying and digitizing brain waves of the patient at a second time subsequent to the first time to generate a second set of digital data;   computing a first trajectory for a first pain index as a function of a comparison of the first and second sets of digital data, using a processor;   determining, using the processor, a recommended rate of delivery of the first interventional agent to the patient as a function of the first trajectory, wherein the first interventional agent is one of an anesthetic, analgesic and amnesic agent; and   outputting to a user the recommended rate of delivery of the first interventional agent.   
     
     
         32 . The method of  claim 31 , further comprising the step of computing a second trajectory for a second pain index as a function of a comparison of the first and second sets of digital data, using a processor. 
     
     
         33 . The method of  claim 31 , further comprising the step of administering to a patient a second interventional agent until the patient attains a second desired level of sensitivity to pain, the second interventional agent being another one of an anesthetic, analgesic and amnesic agent. 
     
     
         34 . The method of  claim 31 , further comprising the step of displaying, via a display, data corresponding to power spectra from each of a plurality of electrodes connected to the patient. 
     
     
         35 . The method of  claim 31 , further comprising the step of using data gathered from of a plurality of electrodes connected to the patient to define a self-norm for the patient. 
     
     
         36 . The method of  claim 35 , further comprising the step of comparing subsequent data gathered from the electrodes to the self-norm. 
     
     
         37 . The method according to  claim 35 , wherein the data corresponds to one of absolute and relative power within each of the plurality of electrodes continuously and within selected frequency bands. 
     
     
         38 . A system, comprising:
 a storage unit having a first set of digital data generated by amplifying and digitizing brain waves of the patient before and at a first time after administration of a first interventional agent to the patient in an amount that attains a first desired level of sensitivity to pain, and a second set of digital data generated by amplifying and digitizing brain waves of the patient at a second time subsequent to the first time;   a processor computing a first trajectory for a first pain index as a function of a comparison of the first and second sets of digital data and determining a recommended rate of delivery of the first interventional agent to the patient as a function of the first trajectory, wherein the first interventional agent is one of an anesthetic, analgesic and amnesic agent; and   a display outputting the recommended rate of delivery of the first interventional agent.   
     
     
         39 . The system of  claim 38 , further comprising a plurality of electroencephalogram (EEG) electrodes coupled to a scalp of the patient and producing electrical signals corresponding to brain waves of the patient. 
     
     
         40 . The system of  claim 39 , wherein the first and second sets of digital data are generated by amplifiers amplifying the electrical signals, an analog-to-digital multiplexer converting the amplified electrical signals into digital signals and a distal signal processor executing a signal processing algorithm on the digital signals.