title: Validation of a polyvinylidene fluoride impedance sensor for respiratory event classification during polysomnography.
abstract: OBJECTIVE
  The AASM has recommended specific sensors in measuring apnea and hypopnea based on published reliability and validity data. As new technology emerges, these guidelines will need revision. Polyvinylidene fluoride (PVDF) measures impedance and can be incorporated into a belt to approximate airflow and respiratory effort. We compared respiratory event detection using PVDF impedance belts (PVDFb), respiratory inductance plethysmography (RIP), and nasal-oral pneumotachography (PNT).
  
  
  METHODS
  First, in a clinical setting, 50 subjects (median AHI 26) undergoing polysomnography were fitted with PVDFb and standard sensors. Studies were scored in 4 independent passes using 4 respiratory montages (M); M1: nasal pressure transduction (NPT), thermistry, and RIP; M2: NPT, thermistry, and PVDFb; M3: thermistry and PVDFb; M4: PVDFb alone. Each experimental montage (M2-M4) was compared to the reference standard (M1) for total apneas and hypopneas. In a second experimental study, respiratory event detection was compared across a series of breathing trials for PVDFb, RIP, and PNT in normal subjects. Agreement was evaluated with intraclass correlation coefficient (ICC), κ statistics, and Bland-Altman plots.
  
  
  RESULTS
  ICCs comparing event numbers by M1 to M 2, 3, and 4 were: 0.99, 0.93, and 0.91, respectively. Almost identical numbers of events were identified for M 1 and M2 (177.5 ± 122.7 vs 177.6 ± 123.2). Event subtypes also were comparable. PVDFb was less sensitive than PNT but no different than RIP in detecting decreased breathing amplitude.
  
  
  CONCLUSIONS
  PVDFb was comparable to standard RIP in determining respiratory events during polysomnography and in detecting decreased breathing amplitude, suggesting that PVDFb can be used as an alternative to RIP for apnea/hypopnea evaluation.
authors: Case Western Reserve University School of Medicine, Department of Neurology, Cleveland, OH 44120, USA. koobri@gmail.com
authors: Brian B
authors: BB
authors: Koo
authors: Colin
authors: C
authors: Drummond
authors: Susan
authors: S
authors: Surovec
authors: Nathan
authors: N
authors: Johnson
authors: Stephanie A
authors: SA
authors: Marvin
authors: Susan
authors: S
authors: Redline
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010992:Plethysmography, Impedance / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D017286:Polysomnography / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D011145:Polyvinyls; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D014159:Transducers; D005465:Fluorocarbon Polymers
chemical_list: D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers