title: Characteristic alteration in the second derivative of photoplethysmogram in children.
abstract: BACKGROUND
  The second derivative of the photoplethysmogram (SDPTG) has been verified as a useful method for analyzing pulse wave form in adults; however, there have been few studies on the SDPTG in children.
  
  
  METHODS
  We examined age-related alteration of SDPTG (study 1) and the SDPTG response to a vasodilator (study 2). The subjects in study 1 were 36 healthy children aged 0.9-16.0 years. The subjects in study 2 were 13 children aged 5.4-18.9 years with a history of Kawasaki disease. Subjects received an i.v. infusion of 0.568 mg/kg dipyridamole. We assessed the SDPTG by d/a ratio, b/a ratio and aging index (AGI).
  
  
  RESULTS
  The d/a ratio increased with advance of age (r= 0.636, P < 0.001), and the b/a ratio and AGI decreased with advance of age (r=-0.343, P < 0.05 and r=-0.678, P < 0.001, respectively). The d/a ratio and AGI were correlated with height (r= 0.523, P < 0.01 and r=-0.623, P < 0.001, respectively), but the b/a ratio was not significantly correlated with height. In study 2, the d/a ratio increased significantly (P≤ 0.05), but the b/a ratio and AGI did not alter.
  
  
  CONCLUSIONS
  The SDPTG indices in children show characteristic alterations with advance of age and react to a vasodilator.
authors.affiliation: Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. shasegawa@med.niigata-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Sato
authors.forename: Fujito
authors.initials: F
authors.lastname: Numano
authors.forename: Jiksoo
authors.initials: J
authors.lastname: Park
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hoshina
authors.forename: Hikosato
authors.initials: H
authors.lastname: Endoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Makoto
authors.initials: M
authors.lastname: Uchiyama
mesh_terms: D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004176:Dipyridamole / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D009080:Mucocutaneous Lymph Node Syndrome / Q000175:diagnosis; D017156:Photoplethysmography / Q000187:drug effects; D011674:Pulse; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D004176:Dipyridamole