title: The long-term stability of portable spirometers used in a multinational study of the prevalence of chronic obstructive pulmonary disease.
abstract: BACKGROUND
  We report the performance of an ultrasound-based portable spirometer (EasyOne) used in a population-based survey of the prevalence of chronic obstructive pulmonary disease, conducted in 5 Latin American cities: São Paulo, Brazil; México City, México; Montevideo, Uruguay; Santiago, Chile; and Caracas, Venezuela (the Latin American COPD Prevalence Study [PLATINO]).
  
  
  METHODS
  During the survey period (which ranged from 3 months to 6 months in the various locations) we collected daily calibration data from the 70 EasyOne spirometers used in the 5 survey cities. The calibrations were conducted with a 3-L syringe, and the calibration data were stored in the spirometer's database.
  
  
  RESULTS
  Ninety-seven percent of the calibration volumes were within +/- 64 mL (2.1%) of the 3-L calibration signal. Excluding data from the first city studied (São Paulo), where one calibration syringe had to be replaced, 98% of the calibration checks were within +/- 50 mL (1.7%). The measured volume was affected only minimally by the syringe's peak flow or emptying time.
  
  
  CONCLUSIONS
  In these 70 EasyOne spirometers neither calibration nor linearity changed during the study. Such calibration stability is a valuable feature in spirometry surveys and in the clinical setting.
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias, Tlalpan 4502, Distrito Federal, Ciudad de México, México 14080. perezpad@servidor.unam.mx
authors.forename: Rogelio
authors.initials: R
authors.lastname: Pérez-Padilla
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Vázquez-García
authors.forename: María Nelly
authors.initials: MN
authors.lastname: Márquez
authors.forename: José Roberto B
authors.initials: JR
authors.lastname: Jardim
authors.forename: Julio
authors.initials: J
authors.lastname: Pertuzé
authors.forename: Carmen
authors.initials: C
authors.lastname: Lisboa
authors.forename: Adriana
authors.initials: A
authors.lastname: Muiño
authors.forename: María Victorina
authors.initials: MV
authors.lastname: López
authors.forename: Carlos
authors.initials: C
authors.lastname: Tálamo
authors.forename: María Montes
authors.initials: MM
authors.lastname: de Oca
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Valdivia
authors.forename: Ana Maria B
authors.initials: AM
authors.lastname: Menezes
mesh_terms: D001938:Brazil / Q000453:epidemiology; D002138:Calibration; D002677:Chile / Q000453:epidemiology; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D013147:Spirometry / Q000295:instrumentation*; D014583:Uruguay / Q000453:epidemiology; D014687:Venezuela / Q000453:epidemiology