title: Validation of a novel device to objectively measure adherence to long-term oxygen therapy.
abstract: BACKGROUND
  We have developed a novel oxygen adherence monitor that objectively measures patient use of long-term oxygen therapy. The monitor attaches to the oxygen source and detects whether or not the patient is wearing the nasal cannula.
  
  
  OBJECTIVE
  The study's purpose was to validate the monitor's performance in patients with chronic obstructive pulmonary disease during wakefulness and sleep.
  
  
  METHODS
  Ten adult males with stable chronic obstructive pulmonary disease (mean +/- SD FEV1 37.7 +/- 14.9% of predicted) on long-term continuous oxygen therapy were tested in a sleep laboratory over a 12-13 hour period that included an overnight polysomnogram.
  
  
  METHODS
  The monitor's measurements were obtained at 4-minute intervals and compared to actual oxygen use determined by review of time-synchronized video recordings.
  
  
  RESULTS
  The monitor made 1504/1888 (79.7%) correct detections (unprocessed data) across all participants: 957/1,118 (85.6%) correct detections during wakefulness and 546/770 (70.9%) during sleep. All errors were false negatives, ie, the monitor failed to detect that the participant was actually wearing the cannula. Application of a majority-vote filter to the raw data improved overall detection accuracy to 84.9%.
  
  
  CONCLUSIONS
  The results demonstrate the monitor's ability to objectively measure whether or not men with chronic obstructive pulmonary disease are receiving their oxygen treatment. The ability to objectively measure oxygen delivery, rather than oxygen expended, may help improve the management of patients on long-term oxygen therapy.
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: Sun-Kai V
authors.initials: SK
authors.lastname: Lin
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Bogen
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Kuna
mesh_terms: D000368:Aged; D006801:Humans; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation* / Q000706:statistics & numerical data; D010349:Patient Compliance / Q000706:statistics & numerical data*; D017286:Polysomnography; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D012890:Sleep / Q000502:physiology; D014741:Video Recording; D014851:Wakefulness / Q000502:physiology