title: Respiratory mechanics of neurological patients undergoing mechanical ventilation under water heated humidifier and a heat exchanger filter model.
abstract: OBJECTIVE
  In mechanically ventilated patients, humidifier devices are used to heat and moisturize the inspired gas. Heating and humidifying inspired gas may prevent complications associated with the respiratory mucosa dryness such as mucus plugging and endotracheal tube occlusion. Two devices have been commonly used to this, either heated humidifier or the heat moisture exchange filter. This study aimed to compare the effects of the heated humidifier and a model of heat moisture exchange filter on respiratory mechanics in mechanically ventilated neurological patients.
  
  
  METHODS
  This was a randomized crossover trial, involving 31 neurological patients under mechanical ventilation randomly assigned to the humidification devices. Expired tidal volume, peak inspiratory flow, peak expiratory flow, static compliance, dynamic compliance and respiratory system resistance were evaluated. Statistical analysis used the Kolmogorov-Smirnov test and Student's t test for paired samples, in which P values < 0.05 were considered significant.
  
  
  RESULTS
  The heat moisture exchanger filter decreased expired tidal volume, peak inspiratory flow, peak expiratory flow (p < 0.001) and dynamic compliance (p = 0.002), and increased respiratory system resistance (p < 0.001).
  
  
  CONCLUSIONS
  In the studied population, the use of a heat moisture exchange filter model leaded to several changes on respiratory mechanics parameters.
authors.affiliation: Faculdade Redentor, Recife, PE, Brasil.
authors.forename: Tiago Branco
authors.initials: TB
authors.lastname: Siqueira
authors.forename: Juliana Cristina Gomes de Freitas
authors.initials: JC
authors.lastname: Costa
authors.affiliation: Faculdade Integrada do Recife, Recife, PE, Brasil.
authors.forename: Isnar Campos
authors.initials: IC
authors.lastname: Tavares
authors.affiliation: Faculdade Integrada do Recife, Recife, PE, Brasil.
authors.forename: Priscilla Muniz
authors.initials: PM
authors.lastname: Torres
authors.forename: Maria do Amparo
authors.initials: Mdo A
authors.lastname: Andrade
authors.affiliation: Universidade Católica de Pernambuco, Recife, PE, Brasil.
authors.forename: Eduardo Ériko Tenório de
authors.initials: EÉ
authors.lastname: França
authors.affiliation: Faculdade Integrada do Recife, Recife, PE, Brasil.
authors.forename: Valdecir Castor
authors.initials: VC
authors.lastname: Galindo Filho
authors.affiliation: Faculdade Integrada do Recife, Recife, PE, Brasil.
authors.forename: Flávio Maciel Dias
authors.initials: FM
authors.lastname: Andrade