title: Novel mathematical processing method of nocturnal oximetry for screening patients with suspected sleep apnoea syndrome.
abstract: OBJECTIVE
  Polysomnography (PSG) is the current standard for diagnosing sleep apnea syndrome (SAS). A reliable test would be useful to reduce the considerable resources required for PSG.
  
  
  METHODS
  We developed a new mathematical analysis, which quantifies amplitude variations of pulse oximetry (SpO(2)) and heart rate (HR) throughout the night, allowing measurement of the total time in which ΔSpO(2) >4% and presented as a new oximetric index ventilatory hypoxemic index (VHI). VHI was compared prospectively with standard PSG parameters apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) in 106 patients (aged, 57 ± 14 years; BMI, 29 ± 5 kg/m(2)) suspected of having SAS. The criterion for diagnosis of SAS was AHI >15/h of sleep during PSG. The relationship between ΔSpO(2) and ΔΗR was also investigated.
  
  
  RESULTS
  We observed a significant correlation between the AHI and VHI (R = 0.87, p < 0.0001). Using VHI >15 as the criterion for SpO(2), oximetry had a sensitivity of 81%, specificity of 98%, positive predictive value (PPV) of 98%, and negative predictive value (NPV) of 84% as a screening test for SAS. We also observed a clear linear relationship between ΔSpO(2) and ΔΗR, and concomitant use of VHI and the ΔSpO(2)/ΔHR slope improved the NPV to 90%.
  
  
  CONCLUSIONS
  The present findings from wavelet-aggregate processing of oximeter data and the relationship between ΔSpO(2) and ΔΗR show promise as a useful summary prediction of screening SAS.
authors.affiliation: Novacor SA, 4 passage Saint Antoine, 92500, Rueil-Malmaison, France. lpoupard@novacor.fr
authors.forename: Laurent
authors.initials: L
authors.lastname: Poupard
authors.forename: Carole
authors.initials: C
authors.lastname: Philippe
authors.forename: Michael David
authors.initials: MD
authors.lastname: Goldman
authors.forename: Richard
authors.initials: R
authors.lastname: Sartène
authors.forename: Marc
authors.initials: M
authors.lastname: Mathieu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D008432:Mathematical Computing; D008875:Middle Aged; D010092:Oximetry / Q000706:statistics & numerical data*; D010100:Oxygen / Q000097:blood; D017286:Polysomnography / Q000706:statistics & numerical data*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D014630:Vagus Nerve / Q000503:physiopathology
chemical_list: D010100:Oxygen