title: Lack of accuracy of ventilatory indexes in predicting extubation success in children submitted to mechanical ventilation.
abstract: OBJECTIVE
  Between 10% and 20% of children submitted to mechanical ventilation in the pediatric intensive care unit present extubation failure. Several ventilatory indexes have been proposed to predict extubation failure. The aim of this study was to analyze the accuracy of these indices in predicting successful extubation in children and to evaluate these variables according to the age of the patient and the specific disease.
  
  
  METHODS
  A prospective observational study including all children submitted to mechanical ventilation in a Brazilian referral pediatric intensive care unit was conducted between August 2007 and August 2008. The tidal volume, maximal negative inspiratory pressure, rapid shallow breathing index and other ventilatory indexes were measured before extubation. These variables were analyzed according to the extubation outcome (success or failure) as well as age and specific disease (post cardiac surgery and acute viral bronchiolitis).
  
  
  RESULTS
  A total of 100 patients were included (median age of 2.1 years old). Extubation failure was observed in 13% and was associated with lower weight (10.3+8.1 Kg vs. 5.5+2.4 Kg; p=0.01). We also evaluated the relationship between extubation failure and the main cause indicating mechanical ventilation: children who had received cardiac surgery (n=17) presented an extubation failure rate of 29.4% with a relative risk of 4.6 (1.2-17.2) when compared to children with acute viral bronchiolitis (n=47, extubation failure rate of 6.4%). The maximal inspiratory pressure was the only physiologic variable independently associated with the outcome. However, this variable showed a wide dispersion and lack of accuracy for predicting extubation success (sensitivity of 82% and specificity of 55% for a cut point of -37.5 cmH2O predicting successful extubation). The same wide dispersion was observed with other ventilatory indexes.
  
  
  CONCLUSIONS
  The indexes for predicting extubation success in children submitted to mechanical ventilation are not accurate; they vary widely depending on age, main disease and other clinical aspects. New formulas including clinical variables should be developed for better prediction of extubation success in children submitted to mechanical ventilation.
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gatiboni
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Jefferson Pedro
authors.initials: JP
authors.lastname: Piva
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Pedro Celiny Ramos
authors.initials: PC
authors.lastname: Garcia
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Cinthia
authors.initials: C
authors.lastname: Jonhston
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Hommerding
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Flávia
authors.initials: F
authors.lastname: Franz
authors.affiliation: Hospital São Lucas, Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Lucien
authors.initials: L
authors.lastname: Gualdi