title: Use of pulse transit time as a measure of autonomic arousals in patients with obstructive sleep apnea.
abstract: OBJECTIVE
  To evaluate the feasibility of pulse transit time (PTT) arousals as an index of sleep fragmentation in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).
  
  
  METHODS
  Individuals referred for evaluation of possible OSAHS underwent overnight polysomnography (PSG). Three conventional indices of sleep fragmentation [electroencephalography (EEG) arousals, apnea/hypopnea index (AHI) , oxygen desaturation index (ODI)] , PTT arousals, and Epworth sleepiness scale (ESS) were compared.
  
  
  RESULTS
  PTT arousals were positively correlated with EEG arousals (r = 0.746, P < 0.001), AHI (r = 0.786, P < 0.001), and ODI (r = 0.665, P < 0.001) , respectively. But, both PTT arousals and EEG arousals had no correlation with ESS (r = 0.432, P = 0.201; r = 0.196, P = 0.591, respectively).
  
  
  CONCLUSIONS
  PTT arousals are correlated well with other standard measures estimating severity of OSAHS and potentially a non-invasive marker with which to measure the sleep fragmentation in patients with OSAHS.
authors.affiliation: Department of Pulmonary Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730. xiaoyipumch@yahoo.com.cn
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
authors.forename: Xu
authors.initials: X
authors.lastname: Zhong
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D004562:Electrocardiography; D004569:Electroencephalography; D006801:Humans; D008875:Middle Aged; D011674:Pulse; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology