Can bispectral index or auditory evoked potential index predict implicit memory during propofol-induced sedation?

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WANG Yun()
YUE Yun()
SUN Yong-hai()
WU An-shi()
Journal Title:
Volume 119, Issue 11, 2006
Key Word:
memory;anesthetic;propofol;electroencephalography;evoked potentials, auditory

Abstract: Background Some patients still suffer from implicit memory of intraoperative events under adequate depth of anaesthesia. The elimination of implicit memory should be a necessary aim of clinical general anaesthesia.However, implicit memory cannot be tested during anaesthesia yet. We propose bispectral index (BIS) and auditory evoked potential index (AEPI), as predictors of implicit memory during anaesthesia.Methods Thirty-six patients were equally divided into 3 groups according to the Observer's Assessment of Alertness/Sedation Score: A, level 3; B, level 2 ;and C, level 1. Every patient was given the first auditory stimulus before sedation. Then every patient received the second auditory stimulus after the target level of sedation had been reached. BIS and AEPI were monitored before and after the second auditory stimulus presentation. Four hours later, the inclusion test and exclusion test were performed on the ward using process dissociation procedure and the scores of implicit memory estimated.Results In groups A and B but not C, implicit memory estimates were statistically greater than zero (P<0.05).The implicit memory scores in group A did not differ significantly from those in group B (P>0.05). Implicit memory scores correlated with BIS and AEPI (P<0.01). The area under ROC curve is BIS> AEPI. The 95% cutoff points of BIS and AEPI for predicting implicit memory are 47 and 28, respectively.Conclusions Implicit memory does not disappear until the depth of sedation increases to level 1 of OAA/S score. Implicit memory scores correlate well with BIS and AEPI during sedation. BIS is a better index for predicting implicit memory than AEPI during propofol induced sedation.

  • [1]Wang Y,Yue Y,Sun YH,Wu AS,Wu QW,Zhang YQ,et al.Investigation and analysis of incidence of awareness in patients undergoing cardiac surgery in Beijing,China.Chin Med J 2005; 118:1190-1194.
  • [2]Sandin RH,Enlund G,Samuelsson P,Lennmarken C.Awareness during anesthesia:a prospective case study.Lancet 2000; 355:707-711.
  • [3]Myles P,Symons J,Leslie K.Anesthetists' attitudes towards awareness and depth-of-anesthesia monitoring.Anesthesia 2003; 58:11-16.
  • [4]Leslie K,Lee L,Myles P,Lerch N,Fiddes C.Patients'knowledge and attitudes towards awareness.Anaesth Intensive Care 2003; 31:63-68.
  • [5]Wang Y,Yue Y,Sun YH,Wu AS,Wu QW.The effect of different levels of propofol sedation on learning and memory.Psychol Sci (Chin) 2003; 26:491-493.
  • [6]Chernik DA,Gillings D,Laine H,Hendler J,Silver JM,Davidson AB,et al.Validity and reliability of the Observer's Assessment of Alertness/Sedation scale:study with intravenous midazolam.J Clin Psychopharmacol 1990; 10:244-251.
  • [7]Wang Y,Yue Y,Sun YH,Wu AS,Wu QW.Relationships between memory and bispectral index (BIS),auditory evoked potential index (AEPI),effective-site concentration during propofol infusion.Chin J Anesthesiology (Chin) 2004; 24:105-108.
  • [8]Myles P,Leslie K,Mcneil J,Forbes A,Chan MT.Bispectral index monitoring to prevent awareness during anaesthesia:the B-aware randomized controlled trial.Lancet 2004;363:1757-1763.
  • [9]Fiset P,Plourde G,Backman SB.Brain imaging in research on anesthetic mechanisms:studies with propofol.Prog Brain Res 2005;150:245-250.
  • [10]Ghoneim MM,Block RI,Dhanaraj VJ,Todd MM,Choi WW,Brown CK.Auditory evoked responses and learning and awareness during general anesthesia.Acta Anesthesiol Scand 2000; 44:133-143.
  • [11]Kotchobey B.Event-related potential measures of consciousness:two equations with three unknowns.Prog Brain Res 2005; 150:427-444.
  • [12]Mi WD,Sakai T,Kudo T,Kudo M,Matsuki A.Performance of bispectral index and auditory evoked potential monitors in detecting loss of consciousness during anaesthetic induction with propofol with and without fentanyl.Eur J Anaesthesiol 2004; 21:807-811.
  • [13]Kerssens C,Ouchi T,Sebel PS.No evidence of memory function during anesthesia with propofol or isoflurane with close control of hypnotic state.Anesthesiology 2005;102:57-62.
  • [14]Veselis RA,Reinsel RA,Feshchenko VA.Drug-induced amnesia is a separate phenomenon from sedation.Anesthesiology 2001; 95:896-907.
  • [15]Jacoby LL.A process dissociation framework:separating automatic from intentional uses of memory.J Mem Lang 1991 ;30:513-541.
  • [16]Stapleton CL,Andrade J.An investigation of learning during propofol sedation and anesthesia using the process dissociation procedure.Anesthesiology 2000;93:1418-1425.
  • [17]Lubke GH,Kerssens C,Phaf H,Sebel PS.Dependence of explicit and implicit memory on hypnotic state in trauma patients.Anesthesiology 1999; 90:670-680.
  • [18]Kerssens C,Lubke GH,Klein J,van der Woerd A,Bonke B.Memory function during propofol and alfentanil anesthesia:predictive value of individual differences.Anesthesiology 2002; 97:382-389.
  • [19]Struys MM,Jensen EW,Smith W,Smith NT,Rampil L,Dumortier F J,et al.Performance of the ARX-derived auditory evoked potential index as an indicator of anesthtic depth.Anesthesiology 2002; 96:803-816.
  • [20]Robert A.Memory function during anesthesia.Anesthesiology 1999; 90:648-650.
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