title: Performance of ventilators compatible with magnetic resonance imaging: a bench study.
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) is indispensable for diagnosing brain and spinal cord abnormalities. Magnetic components cannot be used during MRI procedures; therefore, patient support equipment must use MRI-compatible materials. However, little is known of the performance of MRI-compatible ventilators.
  
  
  METHODS
  At commonly used settings, we tested the delivered tidal volume (V(T)), F(IO2), PEEP, and operation of the high-inspiratory-pressure-relief valves of 4 portable MRI-compatible ventilators (Pneupac VR1, ParaPAC 200DMRI, CAREvent MRI, iVent201) and one ICU ventilator (Servo-i). Each ventilator was set in volume control/continuous mandatory ventilation mode. Breathing frequency and V(T) were tested at 10 breaths/min and 300, 500, and 700 mL, respectively. The Pneupac VR1 has fixed V(T) and frequency combinations, so it was tested at V(T) = 300 mL and 20 breaths/min, V(T) = 500 mL and 12 breaths/min, and V(T) = 800 mL and 10 breaths/min. F(IO2) was 0.6 and 1.0. At the air-mix setting, F(IO2) was fixed at 0.5 with the Pneupac VR1, 0.45 with the ParaPAC 200DMRI, and 0.6 with the CAREvent MRI. PEEP was set at 5 and 10 cm H2O, and pressure relief was set at 30 and 40 cm H2O.
  
  
  RESULTS
  V(T) error varied widely among ventilators (-28.1 to 25.5%). As V(T) increased, error decreased with the Pneupac VR1, ParaPAC 200DMRI, and CAREvent MRI (P < .05). F(IO2) error ranged from -13.3 to 25.3% at 0.6 (or air mix). PEEP error varied among ventilators (-29.2 to 42.5%). Only the Servo-i maintained V(T), F(IO2), and PEEP at set levels. The pressure-relief valves worked in all ventilators.
  
  
  CONCLUSIONS
  None of the MRI-compatible ventilators maintained V(T), F(IO2), and PEEP at set levels. Vital signs of patients with unstable respiratory mechanics should be monitored during transport and MRI.
authors.affiliation: Medical Equipment Center, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Chikata
authors.affiliation: Emergency and Critical Care Medicine, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Okuda
authors.affiliation: Emergency and Critical Care Medicine, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Masayo
authors.initials: M
authors.lastname: Izawa
authors.affiliation: Emergency and Critical Care Medicine, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Onodera
authors.affiliation: Emergency and Critical Care Medicine, Tokushima University Graduate School, Tokushima, Japan. nmasaji@tokushima-u.ac.jp.
authors.forename: Masaji
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D004867:Equipment Design; D006801:Humans; D008279:Magnetic Resonance Imaging; D008422:Materials Testing / Q000379:methods*; D011312:Pressure; D012121:Respiration, Artificial / Q000295:instrumentation*; D013990:Tidal Volume / Q000502:physiology*; D012122:Ventilators, Mechanical / Q000592:standards*
keywords: MRI; MRI-compatible ventilator; magnetic resonance imaging