title: Effect of preoperative anxiety on spectral entropy during induction with propofol.
abstract: BACKGROUND
  Anxiety influences brain wave activity. E-Entropy module-derived spectral entropy is an electroencephalographic derivative used to monitor the depth of sedation. This study assessed the effect of preoperative anxiety on the spectral entropy parameters of response entrophy (RE) and state entrophy (SE).
  
  
  METHODS
  Trait anxiety was measured in 92 American Society of Anesthesiologists physical status I-II patients with the Spielberger State-Trait Anxiety Inventory (STAI) form X2 and state anxiety with STAI-X1 just before anesthesia. RE, SE, blood pressure and heart rate were measured before induction. Propofol was infused via a target controlled infusion pump. At loss of consciousness (LOC), the effect-site concentration (Ce), RE, SE and total amount of propofol were recorded. Patients were stratified into three groups based on their state and trait anxiety scores to evaluate the effect of anxiety level on entropy values.
  
  
  RESULTS
  STAI-X1 was significantly correlated with RE and SE for LOC (ρ = 0.230, P = 0.028 and ρ = 0.308, P = 0.003, respectively) and also with STAI-X2 (ρ = 0.411, P = 0.001, respectively). SE was higher in the high state anxiety group than in the low state anxiety group (P = 0.017). The other measured variables were not correlated with any anxiety scales.
  
  
  CONCLUSIONS
  The state of anxiety increases RE and SE values at LOC induced with propofol. High state anxiety is associated with higher SE than apparent at low state anxiety. When determining the propofol-induced LOC by spectral entropy, anxiety levels should be considered.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Korea.
authors.forename: Yun Hong
authors.initials: YH
authors.lastname: Kim
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Choi
keywords: Anxiety; Electroencephalography; Entropy; Propofol
references.citation: J Neurosci. 1999 Jul 1;19(13):5506-13
references.pmid: 10377359
references.citation: Psychiatry Res. 2004 Sep 15;131(3):237-47
references.pmid: 15465293
references.citation: Acta Anaesthesiol Scand. 2004 Feb;48(2):154-61
references.pmid: 14995936
references.citation: Biol Res Nurs. 2012 Apr;14(2):197-206
references.pmid: 21586498
references.citation: Br J Anaesth. 2004 Feb;92(2):167-70
references.pmid: 14722164
references.citation: Br J Anaesth. 2008 Aug;101(2):213-21
references.pmid: 18550642
references.citation: Br J Anaesth. 2003 Feb;90(2):127-31
references.pmid: 12538366
references.citation: Int J Psychophysiol. 2009 Feb;71(2):156-69
references.pmid: 18848849
references.citation: Int J Psychophysiol. 2011 Jun;80(3):236-45
references.pmid: 21458502
references.citation: J Neurosurg Anesthesiol. 1997 Oct;9(4):335-40
references.pmid: 9339406
references.citation: J Neuropsychiatry Clin Neurosci. 1999 Spring;11(2):190-208
references.pmid: 10333991
references.citation: Acta Anaesthesiol Scand. 2001 Mar;45(3):298-307
references.pmid: 11207465
references.citation: Int J Neurosci. 1996 Sep;86(3-4):197-205
references.pmid: 8884390
references.citation: J Clin Monit Comput. 2011 Oct;25(5):309-14
references.pmid: 21964767
references.citation: J Clin Psychopharmacol. 1990 Aug;10(4):244-51
references.pmid: 2286697
references.citation: J Neurosurg Anesthesiol. 2006 Jul;18(3):205-10
references.pmid: 16799349
references.citation: J Neurosci. 2008 Dec 10;28(50):13488-504
references.pmid: 19074022
references.citation: Br J Anaesth. 2012 Jan;108(1):119-25
references.pmid: 22084330
references.citation: J Clin Monit Comput. 2008 Apr;22(2):87-93
references.pmid: 18253846
references.citation: Anesth Analg. 1999 Dec;89(6):1346-51
references.pmid: 10589606