title: Influence of dynamic leaks in volume-targeted pressure support noninvasive ventilation: a bench study.
abstract: BACKGROUND
  The effect of leaks on volume-targeted pressure support noninvasive ventilation mode has only been tested with continuous simulated leaks. The objective of the study was to assess the influence of random leaks occurring either during inspiration or expiration.
  
  
  METHODS
  Analysis of the volume-targeted pressure support mode in 6 commercial ventilators with single-limb circuits and intentional leak in a bench study (restrictive model). Unintentional leaks were introduced through a mechanical system during inspiration (threshold valve with 2 levels of leaks) or during expiration (active valve). Results of delivered tidal volume (VT) and pressure support were externally recorded. A pre-set VT of 550 mL was programmed, with a wide range of pressure support values.
  
  
  RESULTS
  All the ventilators showed a deviation of delivered versus programmed VT below 10% in the period without unintentional leaks. In the model with unintentional inspiratory leaks, a progressive drop in delivered VT and pressure support was observed for all ventilators. The reduction in the delivered VT for the highest inspiratory leak ranged between 21 and 40%, corresponding to a decrease in pressure support between 3.09 and 10.15 cm H2O after 5 min. Conversely, in the expiratory model, increases in delivered VT and pressure support were observed, ranging between 16 and 33% and between 2.7 and 6.5 cm H2O, respectively.
  
  
  CONCLUSIONS
  The introduction of random leaks influences the performance of commercial ventilators with single-limb circuits and intentional leak. The decrease in delivered VT with inspiratory leaks reaches a magnitude that may have clinically important impacts.
authors.affiliation: Servei de Pneumologia, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid mlujan@tauli.cat.
authors.forename: Manel
authors.initials: M
authors.lastname: Luján
authors.affiliation: Servei de Pneumologia, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell.
authors.forename: Ana
authors.initials: A
authors.lastname: Sogo
authors.affiliation: Servei de Pneumologia, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell.
authors.forename: Carles
authors.initials: C
authors.lastname: Grimau
authors.affiliation: Servei de Pneumologia, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell.
authors.forename: Xavier
authors.initials: X
authors.lastname: Pomares
authors.affiliation: Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid Critical Care Department, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell, Spain.
authors.forename: Lluís
authors.initials: L
authors.lastname: Blanch
authors.affiliation: Servei de Pneumologia, Corporaciò Sanitària Parc Taulí, Hospital de Sabadell, Universitat Autònoma de Barcelona, Parc Taulí, Sabadell Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid.
authors.forename: Eduard
authors.initials: E
authors.lastname: Monsó
mesh_terms: D019544:Equipment Failure Analysis; D045853:Exhalation; D006801:Humans; D001239:Inhalation; D063087:Noninvasive Ventilation / Q000295:instrumentation* / Q000379:methods; D013990:Tidal Volume; D012122:Ventilators, Mechanical
keywords: dual-control mode; leaks; noninvasive ventilation; volume-targeted pressure support