title: Oxygen Desaturation Index Estimation through Unconstrained Cardiac Sympathetic Activity Assessment Using Three Ballistocardiographic Systems.
abstract: BACKGROUND
  Nocturnal hypoxemia, characterized by abnormally low oxygen saturation levels in arterial blood during sleep, is a significant feature of various pathological conditions. The oxygen desaturation index, commonly used to evaluate the nocturnal hypoxemia severity, is acquired using nocturnal pulse oximetry that requires the overnight wear of a pulse oximeter probe.
  
  
  OBJECTIVE
  This study aimed to suggest a method for the unconstrained estimation of the oxygen desaturation index.
  
  
  METHODS
  We hypothesized that the severity of nocturnal hypoxemia would be positively associated with cardiac sympathetic activation during sleep. Unconstrained heart rate variability monitoring was conducted using three different ballistocardiographic systems to assess cardiac sympathetic activity. Overnight polysomnographic and ballistocardiographic recording pairs were collected from the 20 non-nocturnal hypoxemia (oxygen desaturation index <5 events/h) subjects and the 76 nocturnal hypoxemia patients. Among the 96 recording pairs, 48 were used as training data and the remaining 48 as test data.
  
  
  RESULTS
  The regression analysis, performed using the low-frequency component of heart rate variability, exhibited a root mean square error of 3.33 events/h between the estimates and the reference values of the oxygen desaturation index. The nocturnal hypoxemia diagnostic performance produced by our method was presented with an average accuracy of 96.5% at oxygen desaturation index cutoffs of ≥5, 15, and 30 events/h.
  
  
  CONCLUSIONS
  Our method has the potential to serve as a complementary measure against the accidental slip-out of a pulse oximeter probe during nocturnal pulse oximetry. The independent application of our method could facilitate home-based long-term oxygen desaturation index monitoring.
authors.affiliation: Interdisciplinary Program for Biomedical Engineering, Seoul National University Graduate School, Seoul, South Korea.
authors.forename: Da Woon
authors.initials: da W
authors.lastname: Jung
authors.forename: Su Hwan
authors.initials: SH
authors.lastname: Hwang
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Do-Un
authors.initials: DU
authors.lastname: Jeong
authors.forename: Kwang Suk
authors.initials: KS
authors.lastname: Park
mesh_terms: D000328:Adult; D001450:Ballistocardiography / Q000295:instrumentation*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D017286:Polysomnography; D012890:Sleep
chemical_list: D010100:Oxygen