title: Reference values for airway resistance in newborns, infants and preschoolers from a Latin American population.
abstract: OBJECTIVE
  Several studies have determined reference values for airway resistance measured by the interrupter technique (Rint) in paediatric populations, but only one has been done on Latin American children, and no studies have been performed on Mexican children. Moreover, these previous studies mostly included children aged 3 years and older; therefore, information regarding Rint reference values for newborns and infants is scarce.
  
  
  METHODS
  Rint measurements were performed on preschool children attending eight kindergartens (Group 1) and also on sedated newborns, infants and preschool children admitted to a tertiary-level paediatric hospital due to non-cardiopulmonary disorders (Group 2).
  
  
  RESULTS
  In both groups, Rint values were inversely associated with age, weight and height, but the strongest association was with height. The linear regression equation for Group 1 (n = 209, height 86-129 cm) was Rint = 2.153 - 0.012 × height (cm) (standard deviation of residuals 0.181 kPa/L/s). The linear regression equation for Group 2 (n = 55, height 52-113 cm) was Rint = 4.575 - 0.035 × height (cm) (standard deviation of residuals 0.567 kPa/L/s). Girls tended to have slightly higher Rint values than boys, a difference that diminished with increasing height.
  
  
  CONCLUSIONS
  In this study, Rint reference values applicable to Mexican children were determined, and these values are probably also applicable to other paediatric populations with similar Spanish-Amerindian ancestries. There was an inverse relationship between Rint and height, with relatively large between-subject variability.
authors.affiliation: Center for Evaluation of the Paediatric Asthma Patient, Centro Médico Santa Teresa, Texcoco, México.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Gochicoa
authors.forename: Laura P
authors.initials: LP
authors.lastname: Thomé-Ortiz
authors.forename: María E Y
authors.initials: ME
authors.lastname: Furuya
authors.forename: Raquel
authors.initials: R
authors.lastname: Canto
authors.forename: Martha E
authors.initials: ME
authors.lastname: Ruiz-García
authors.forename: Guillermo
authors.initials: G
authors.lastname: Zúñiga-Vázquez
authors.forename: Filiberto
authors.initials: F
authors.lastname: Martínez-Ramírez
authors.forename: Mario H
authors.initials: MH
authors.lastname: Vargas
mesh_terms: D000403:Airway Resistance / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D008800:Mexico; D011446:Prospective Studies; D012016:Reference Values; D012129:Respiratory Function Tests / Q000379:methods / Q000592:standards