title: Monitoring of noninvasive ventilation by built-in software of home bilevel ventilators: a bench study.
abstract: BACKGROUND
  Current bilevel positive-pressure ventilators for home noninvasive ventilation (NIV) provide physicians with software that records items important for patient monitoring, such as compliance, tidal volume (Vt), and leaks. However, to our knowledge, the validity of this information has not yet been independently assessed.
  
  
  METHODS
  Testing was done for seven home ventilators on a bench model adapted to simulate NIV and generate unintentional leaks (ie, other than of the mask exhalation valve). Five levels of leaks were simulated using a computer-driven solenoid valve (0-60 L/min) at different levels of inspiratory pressure (15 and 25 cm H(2)O) and at a fixed expiratory pressure (5 cm H(2)O), for a total of 10 conditions. Bench data were compared with results retrieved from ventilator software for leaks and Vt.
  
  
  RESULTS
  For assessing leaks, three of the devices tested were highly reliable, with a small bias (0.3-0.9 L/min), narrow limits of agreement (LA), and high correlations (R(2), 0.993-0.997) when comparing ventilator software and bench results; conversely, for four ventilators, bias ranged from -6.0 L/min to -25.9 L/min, exceeding -10 L/min for two devices, with wide LA and lower correlations (R(2), 0.70-0.98). Bias for leaks increased markedly with the importance of leaks in three devices. Vt was underestimated by all devices, and bias (range, 66-236 mL) increased with higher insufflation pressures. Only two devices had a bias < 100 mL, with all testing conditions considered.
  
  
  CONCLUSIONS
  Physicians monitoring patients who use home ventilation must be aware of differences in the estimation of leaks and Vt by ventilator software. Also, leaks are reported in different ways according to the device used.
authors.affiliation: Division of Pulmonary Diseases, Geneva University Hospital, Geneva, Switzerland. Electronic address: Olivier.Contal@hcuge.ch.
authors.forename: Olivier
authors.initials: O
authors.lastname: Contal
authors.affiliation: Intensive Care Unit, and CRC & Division of Cinical-Epidemiology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Laurence
authors.initials: L
authors.lastname: Vignaux
authors.affiliation: Department of Health and Community Medicine, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Combescure
authors.affiliation: Institut National de la Sante et de la Recherche Médicale, Unit 1042, University Hospital, Grenoble, France; SomnoNIV Group, University Hospital of Lausanne, Switzerland.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pepin
authors.affiliation: Intensive Care Unit, University Hospital of Lausanne, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Jolliet
authors.affiliation: Division of Pulmonary Diseases, Geneva University Hospital, Geneva, Switzerland; SomnoNIV Group, University Hospital of Lausanne, Switzerland.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Janssens
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006699:Home Care Services; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D015203:Reproducibility of Results; D012984:Software; D012122:Ventilators, Mechanical