title: Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study.
abstract: OBJECTIVE
  Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM.
  
  
  METHODS
  This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization.
  
  
  RESULTS
  Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly.
  
  
  CONCLUSIONS
  The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM.
authors.affiliation: Heart Institute, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Maria Aparecida Miyuki
authors.initials: MA
authors.lastname: Nakamura
authors.affiliation: Heart Institute, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Eduardo Leite Vieira
authors.initials: EL
authors.lastname: Costa
authors.affiliation: Department of Cardiorespiratory Diseases, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Carlos Roberto Ribeiro
authors.initials: CR
authors.lastname: Carvalho
authors.affiliation: Department of Pulmonology, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Mauro Roberto
authors.initials: MR
authors.lastname: Tucci
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods / Q000592:standards*; D006801:Humans; D007362:Intensive Care Units; D008397:Masks / Q000009:adverse effects / Q000592:standards*; D008954:Models, Biological; D063087:Noninvasive Ventilation / Q000009:adverse effects / Q000295:instrumentation*; D012122:Ventilators, Mechanical / Q000009:adverse effects / Q000592:standards*