title: Nocturnal home pulse oximetry: variability and clinical implications in home mechanical ventilation.
abstract: BACKGROUND
  Nocturnal home pulse oximetry (NHPO) provides information by measuring a series of variables: time spent with SaO(2) <90% expressed as percentage (T90) or in minutes (Tm90), mean SaO(2) (MnS), and lowest SaO(2) (LwS.) The presence of significant nocturnal desaturation has been proposed as a parameter in decision making with regard to initiating home mechanical ventilation (HMV) or monitoring HMV effectiveness. However, there is limited information on the possible variability of the test, and this could influence the interpretation of results.
  
  
  OBJECTIVE
  To explore the variability between 2 consecutive measurements of NHPO and to determine clinical applications in HMV.
  
  
  METHODS
  The patients presented diseases susceptible to HMV treatment and were enrolled in stable condition without respiratory failure. NHPO was conducted on 2 consecutive nights. The variables analyzed were: T90, Tm90, Mns, and LwS. The coefficient of variation (CV), a concordance coefficient (CC), and the Bland-Altman method were used in order to explore the variability.
  
  
  RESULTS
  We studied 40 cases. Two were excluded, and the remaining 38 were aged 58 ± 16 years (19 males). Eighteen were receiving HMV. CV values exceeded 100% for T90 and Tm90 and were below 5% for MnS and LwS. The CC for T90, Tm90, and LwS showed confidence intervals with lower limits below 0.5, while for MnS the value was 0.88 (0.79-0.93).
  
  
  CONCLUSIONS
  There is a wide variability in NHPO recordings for T90, Tm90, and LwS, so a single determination to detect nocturnal desaturation may not be valid for decision making; the parameter with the least interindividual variability and intraindividual variability was MnS.
authors.affiliation: Neumología, Hospital Universitario Central de Asturias, Oviedo, España. enelllano@gmail.com
authors.forename: Ramón
authors.initials: R
authors.lastname: Fernández
authors.forename: Gemma
authors.initials: G
authors.lastname: Rubinos
authors.forename: Cristina
authors.initials: C
authors.lastname: Cabrera
authors.forename: Rosa
authors.initials: R
authors.lastname: Galindo
authors.forename: Sergio
authors.initials: S
authors.lastname: Fumero
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sosa
authors.forename: Isidro
authors.initials: I
authors.lastname: González
authors.forename: Pere
authors.initials: P
authors.lastname: Casan
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D012121:Respiration, Artificial / Q000379:methods*; D012140:Respiratory Tract Diseases / Q000503:physiopathology* / Q000628:therapy*