title: Effect of dynamic random leaks on the monitoring accuracy of home mechanical ventilators: a bench study.
abstract: BACKGROUND
  So far, the accuracy of tidal volume (VT) and leak measures provided by the built-in software of commercial home ventilators has only been tested using bench linear models with fixed calibrated and continuous leaks. The objective was to assess the reliability of the estimation of tidal volume (VT) and unintentional leaks in a single tubing bench model which introduces random dynamic leaks during inspiratory or expiratory phases.
  
  
  METHODS
  The built-in software of four commercial home ventilators and a fifth ventilator-independent ad hoc designed external software tool were tested with two levels of leaks and two different models with excess leaks (inspiration or expiration). The external software analyzed separately the inspiratory and expiratory unintentional leaks.
  
  
  RESULTS
  In basal condition, all ventilators but one underestimated tidal volume with values ranging between -1.5 ± 3.3% to -8.7% ± 3.27%. In the model with excess of inspiratory leaks, VT was overestimated by all four commercial software tools, with values ranging from 18.27 ± 7.05% to 35.92 ± 17.7%, whereas the ventilator independent-software gave a smaller difference (3.03 ± 2.6%). Leaks were underestimated by two applications with values of -11.47 ± 6.32 and -5.9 ± 0.52 L/min. With expiratory leaks, VT was overestimated by the software of one ventilator and the ventilator-independent software and significantly underestimated by the other three, with deviations ranging from +10.94 ± 7.1 to -48 ± 23.08%. The four commercial tools tested overestimated unintentional leaks, with values between 2.19 ± 0.85 to 3.08 ± 0.43 L/min.
  
  
  CONCLUSIONS
  In a bench model, the presence of unintentional random leaks may be a source of error in the measurement of VT and leaks provided by the software of home ventilators. Analyzing leaks during inspiration and expiration separately may reduce this source of error.
authors: Ana
authors: A
authors: Sogo
authors: Jaume
authors: J
authors: Montanyà
authors: Eduard
authors: E
authors: Monsó
authors: Lluís
authors: L
authors: Blanch
authors: Xavier
authors: X
authors: Pomares
authors: Department of Pneumology, Corporació Sanitària Parc Taulí, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain. mlujan@tauli.cat.
authors: Manel
authors: M
authors: Lujàn
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006699:Home Care Services; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012984:Software; D013990:Tidal Volume; D012122:Ventilators, Mechanical