System and method of assessing analgesic adequacy using biopotential variability

Abstract

The system and method for predicting and measuring a subject's analgesic state and analgesic adequacy. Biopotential signals are obtained from a subject through electrodes. A processor will compute a measure that is representative of the subject's sedative state and/or muscle activity. A metric representative of such measures is then determined. In the case where a measure is taken of both the subject's sedative state and muscle activity the two measures are combined into an index representative of the subject's analgesic state and analgesic adequacy.

1 . A system for assessing a subject's analgesic state and adequacy comprising: 
 electrodes for obtaining biopotential signals from said subject; and    a processor for (a) computing from said biopotential signals a first measure representative of said subject's sedative state, (b) determining a metric representative of variability of said first measure, and (c) combining said first metric into an index representative of said subject's analgesic state and analgesic adequacy.    
   
   
       2 . The system for assessing a subject's analgesic state and adequacy of  claim 1  wherein said processor assigns weights to said first measure combines said first metrics based on said weights.  
   
   
       3 . A system for assessing a subject's analgesic state and adequacy comprising: 
 electrodes for obtaining biopotential signals from said subject; and    a processor for (a) computing from said biopotential signals a first measure representative of said subject's sedative state, (b) determining a metric representative of variability of said first measure, (c) computing from said biopotential signals a second measure representative of said subject's muscle activity, (d) determining a metric representative of said subject's muscle activity and (e) combining said first metric and second metric into an index representative of said subject's analgesic state and analgesic adequacy.    
   
   
       4 . The system for assessing a subject's analgesic state and adequacy of  claim 3  wherein said processor assigns weights to said first measure and said second measure and combines said first metrics and second metrics based on said weights.  
   
   
       5 . The system for assessing a subject's analgesic state and adequacy of  claim 1  wherein said processor time synchronizes said first measure and said second measure.  
   
   
       6 . A method of assessing a subject's analgesic state and adequacy comprising the steps of: 
 placing biopotential electrodes on said subject,    collecting biopotential signals through said electrodes from said subject,    computing from said collected biopotential signals a first measure representative of said subject's sedative state,    determining a metric representative of variability of said first measure and,    combining said first metric into an index representative of said subject's analgesic state and analgesic adequacy.    
   
   
       7 . The method of assessing a subject's analgesic state and adequacy of  claim 6  further comprising the step of assigning weights to said first measure and wherein said step of combining said first metric combines said first metrics based on said weights.  
   
   
       8 . A method of assessing a subject's analgesic state and adequacy comprising the steps of: 
 placing biopotential electrodes on said subject,    collecting biopotential signals through said electrodes from said subject,    computing from said collected biopotential signals a first measure representative of said subject's sedative state,    determining a metric representative of variability of said first measure,    computing from said collected biopotential signals a second measure representative of said subject's muscle activity,    determining a metric representative of variability of said second measure and,    combining said first metric and said second metric into an index representative of said subject's analgesic state and analgesic adequacy.    
   
   
       9 . The method of assessing a subject's analgesic state and adequacy of  claim 8  further comprising the step of assigning weights to said first measure and said second measure and wherein said step of combining said first metric and said second metric combines said first metric and said second metric based on said weights.  
   
   
       10 . The method of assessing a subject's analgesic state and adequacy of  claim 8  further comprising the step of time synchronizing said first measure and said second measure.  
   
   
       11 . The method of improving postoperative patient outcome comprising the steps of: 
 placing biopotential electrodes on said patient,    collecting biopotential signals through said electrodes from said patient,    computing from said collected biopotential signals a first measure representative of said patient's sedative state,    determining a metric representative of variability of said first measure,    computing from said collected biopotential signals a second measure representative of said patient's muscle activity,    determining a metric representative of the variability of said second measure,    combining said first metric and said second metric into an index representative of said subject's analgesic state and analgesic adequacy, and    administering pharmacological agents to said patient in order to minimize the occurrence of sudden increases in said index representative of said patient's analgesic state and analgesic adequacy.    
   
   
       12 . The method of assessing a subject's analgesic state and adequacy of  claim 11  further comprising the step of assigning weights to said first measure and said second measure and wherein said step of combining said first metric and said second metric combines said first metric and said second metric based on said weights.  
   
   
       13 . The method of assessing a subject's analgesic state and adequacy of  claim 11  further comprising the step of time synchronizing said first measure and said second measure.