title: Preoperative ultra short-term entropy predicts arterial blood pressure fluctuation during the induction of anesthesia.
abstract: BACKGROUND
  In this study, we sought to determine whether the preoperative nonlinear index of heart rate variability, ultra short-term entropy (UsEn), could predict cardiovascular responses to the induction of general anesthesia.
  
  
  METHODS
  UsEn was estimated by a linearized version of the nonlinear least squares method combined with the maximum entropy spectral analysis method (MemCalc method). Preoperative UsEn of 46 patients (ASA PS 1 or 2, aged 40-60 yr) without a history of hypertension was evaluated using the MemCalc method. Patients were assigned to two groups according to preoperative UsEn (Group LOW; UsEn <45, Group HIGH; UsEn > or =45). Anesthesia was induced with propofol, fentanyl and vecuronium bromide and endotracheal intubation was performed. Hemodynamic fluctuations during the induction of anesthesia were recorded and compared between the two groups.
  
  
  RESULTS
  It was found that arterial blood pressure fluctuations during the induction of anesthesia were significantly greater in patients with a low UsEn.
  
  
  CONCLUSIONS
  UsEn could predict arterial blood pressure fluctuations during the induction of anesthesia.
authors: Department of Anesthesiology, Aichi Medical University School of Medicine, Japan. yyoshiff@aichi-med-u.ac.jp
authors: Yoshihiro
authors: Y
authors: Fujiwara
authors: Hiroshi
authors: H
authors: Ito
authors: Yusuke
authors: Y
authors: Asakura
authors: Yuko
authors: Y
authors: Sato
authors: Kimitoshi
authors: K
authors: Nishiwaki
authors: Toru
authors: T
authors: Komatsu
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000009:adverse effects*; D018686:Anesthetics, Intravenous / Q000009:adverse effects*; D001794:Blood Pressure / Q000187:drug effects*; D004562:Electrocardiography; D019277:Entropy; D005260:Female; D005283:Fentanyl / Q000009:adverse effects; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007022:Hypotension / Q000139:chemically induced* / Q000503:physiopathology; D007442:Intubation, Intratracheal; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged; D003473:Neuromuscular Nondepolarizing Agents / Q000009:adverse effects*; D017711:Nonlinear Dynamics; D011237:Predictive Value of Tests; D011300:Preoperative Care; D015742:Propofol / Q000009:adverse effects; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014673:Vecuronium Bromide / Q000009:adverse effects
chemical_list: D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide; D005283:Fentanyl; D015742:Propofol