title: Values of impulse oscillometry in healthy mexican children and adolescents.
abstract: BACKGROUND
  The impulse oscillometry system (IOS) is increasingly used to evaluate lung function, but individual results must be compared with appropriate reference values. We aimed to obtain such reference values in Mexican children and adolescents.
  
  
  METHODS
  Healthy subjects were recruited from kindergartens and schools after their parents signed a consent letter. Respiratory system impedances (Zrs), resistances (Rrs), and reactances (Xrs) were measured at 5, 10, 15, and 20 Hz, and the resonant frequency, reactance area, and difference between Rrs5 minus Rrs20 were also calculated.
  
  
  RESULTS
  After exclusion of 4 children who were unable to perform an acceptable IOS recording, the final population comprised 283 children (153 females) 2.7-15.4 y of age. As a group, girls tended to have lower Xrs5 and higher Zrs20 and Rrs20 values. In bivariate analyses, all IOS variables had good correlation with age, height, and weight, and a better straight-line fitting was obtained through data transformation to the log10 (age) or reciprocal (height and weight) values. Comparison of regression lines revealed small differences between males and females, especially in Xrs. Multiple linear regression analysis identified height as the most influential variable in the majority of IOS variables, but age also accounted for a moderate-to-large influence in the regression models in many IOS variables.
  
  
  CONCLUSIONS
  In this study, we generated reference equations for each IOS variable in healthy children and adolescents. Although these equations were generated in a Mexican population, they are probably also applicable in other Latin American populations with the same ethnic background.
authors.affiliation: Departamento de Fisiología Respiratoria, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF Centro de Evaluación del Paciente Asmático Infantil, Centro Médico Santa Teresa, Texcoco, Estado de México.
authors.forename: Laura
authors.initials: L
authors.lastname: Gochicoa-Rangel
authors.affiliation: Departamento de Fisiología Respiratoria, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF.
authors.forename: Luis
authors.initials: L
authors.lastname: Torre-Bouscoulet
authors.affiliation: Departamento de Investigación en Epidemiología y Ciencias Sociales en Salud, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF.
authors.forename: David
authors.initials: D
authors.lastname: Martínez-Briseño
authors.affiliation: Departamento de Fisiología Respiratoria, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF.
authors.forename: Luis
authors.initials: L
authors.lastname: Rodríguez-Moreno
authors.affiliation: Departamento de Fisiología Respiratoria, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Cantú-González
authors.affiliation: Departamento de Investigación en Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México DF, and the Unidad de Investigación Médica en Enfermedades Respiratorias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México DF, México. mhvargasb@yahoo.com.mx.
authors.forename: Mario H
authors.initials: MH
authors.lastname: Vargas
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000403:Airway Resistance / Q000502:physiology; D001827:Body Height; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008800:Mexico; D009991:Oscillometry; D010992:Plethysmography, Impedance; D012016:Reference Values; D012129:Respiratory Function Tests / Q000379:methods; D012737:Sex Factors
keywords: impulse oscillometry; normal values; reference values; respiratory impedance; respiratory reactance; respiratory resistance