title: Thermal infrared imaging: a novel method to monitor airflow during polysomnography.
abstract: OBJECTIVE
  This is a feasibility study designed to evaluate the accuracy of thermal infrared imaging (TIRI) as a noncontact method to monitor airflow during polysomnography and to ascertain the chance-corrected agreement (K) between TIRI and conventional airflow channels (nasal pressure [Pn], oronasal thermistor and expired CO2 [P(E)CO2]) in the detection of apnea and hypopnea.
  
  
  METHODS
  Subjects were recruited to undergo polysomnography for 1 to 2 hours, during which simultaneous recordings from electroencephalography, electrooculography, electromyography, respiratory impedance plethysmography, conventional airflow channels, and TIRI were obtained.
  
  
  METHODS
  University-affiliated, American Academy of Sleep Medicine-accredited sleep disorders center.
  
  
  METHODS
  Fourteen volunteers without a history of sleep disordered breathing and 13 patients with a history of obstructive sleep apnea were recruited.
  
  
  RESULTS
  In the detection of apnea and hypopnea, excellent agreement was noted between TIRI and thermistor (kappa = 0.92, Bayesian Credible Interval [BCI] 0.86, 0.96; pkappa = 0.99). Good agreement was noted between TIRI and Pn (kappa = 0.83, BCI 0.70, 0.90; pkappa = 0.98) and between TIRI and P(E)CO2 (kappa = 0.80, BCI 0.66, 0.89; pkappa = 0.94).
  
  
  CONCLUSIONS
  TIRI is a feasible noncontact technology to monitor airflow during polysomnography. In its current methodologic incarnation, it demonstrates a high degree of chance-corrected agreement with the oronasal thermistor in the detection of apnea and hypopneas but demonstrates a lesser degree of chance-corrected agreement with Pn. Further overnight validation studies must be performed to evaluate its potential in clinical sleep medicine.
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA. Jayasimha.Murthy@uth.tmc.edu
authors.forename: Jayasimha N
authors.initials: JN
authors.lastname: Murthy
authors.forename: Johan
authors.initials: J
authors.lastname: van Jaarsveld
authors.forename: Jin
authors.initials: J
authors.lastname: Fei
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pavlidis
authors.forename: Rajesh I
authors.initials: RI
authors.lastname: Harrykissoon
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Lucke
authors.forename: Saadia
authors.initials: S
authors.lastname: Faiz
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Castriotta
mesh_terms: D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D015992:Body Mass Index; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity; D017286:Polysomnography; D012123:Pulmonary Ventilation / Q000502:physiology*; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D013817:Thermography / Q000379:methods*; D055815:Young Adult