title: Identification of patients with childhood moyamoya diseases showing temporary hypertension after anesthesia by preoperative multifractal Hurst analysis of heart rate variability.
abstract: OBJECTIVE
  This study was performed to determine whether the preoperative multifractal Hurst analysis of heart rate variability might identify and characterize childhood patients with moyamoya disease (MMD) who showed temporary postoperative hypertension.
  
  
  METHODS
  We studied 59 childhood patients with MMD. Thirty were classified as hypertensive group when the mean arterial pressure in the postoperative recovery room was 120% or greater than that during the preoperative period and 29 were classified as normotensive group. The 2 groups were compared with respect to preoperative indices of heart rate variability including frequency-domain measures, approximate entropy, and very short-term multifractal Hurst exponents of RR intervals (RRI). Using preoperative indices that showed significant differences, discriminant analysis was performed to identify postoperative hypertensive patients.
  
  
  RESULTS
  Only exponents of the order > or =3 (H3alpha, H4alpha, and H5alpha) were significantly lower in the hypertensive group than in the normotensive group. Frequency-domain measures, approximate entropy, and the exponents of the order < or =2 were not significantly different in the 2 groups. Discriminant analysis using all of the three exponents correctly identified 27/30 (90%) of the postoperative hypertensive patients.
  
  
  CONCLUSIONS
  Preoperative very short-term multifractal Hurst analysis of RRI variability identified 90% of childhood MMD patients who developed postoperative hypertension. The preoperative characteristic of RRI variability was the reduced smoothness at the 8-second-long, local RRI regions within which a very large change of RRI occurs.
authors.affiliation: Department of Pediatrics, College of Medicine, Hanyang University, Korea.
authors.forename: Myung-Kul
authors.initials: MK
authors.lastname: Yum
authors.forename: A-Young
authors.initials: AY
authors.lastname: Oh
authors.forename: Hyo-Min
authors.initials: HM
authors.lastname: Lee
authors.forename: Chong-Sung
authors.initials: CS
authors.lastname: Kim
authors.forename: Seong-Deok
authors.initials: SD
authors.lastname: Kim
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Lee
authors.forename: Kyu-Chang
authors.initials: KC
authors.lastname: Wang
authors.forename: You-Nam
authors.initials: YN
authors.lastname: Chung
authors.forename: Hee-Soo
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000758:Anesthesia / Q000009:adverse effects*; D002536:Cerebral Arteries / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D019277:Entropy; D005260:Female; D017709:Fractals; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D008297:Male; D015233:Models, Statistical; D009072:Moyamoya Disease / Q000175:diagnosis* / Q000503:physiopathology*; D019635:Neurosurgical Procedures; D011183:Postoperative Complications / Q000139:chemically induced / Q000503:physiopathology*