title: Temperature of gas delivered from ventilators.
abstract: BACKGROUND
  Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV).
  
  
  METHODS
  We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings.
  
  
  RESULTS
  While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature.
  
  
  CONCLUSIONS
  Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.
authors.affiliation: Emergency and Critical Care Medicine, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima City, 770-8503 Japan ; Medical Equipment Center, Tokushima University Hospital, 2-50-1 Kuramoto, Tokushima City, 770-8503 Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Chikata
authors.affiliation: Emergency and Critical Care Medicine, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima City, 770-8503 Japan.
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Onodera
authors.affiliation: Emergency and Disaster Medicine, Tokushima University Hospital, 2-50-1 Kuramoto, Tokushima City, 770-8503 Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Imanaka
authors.affiliation: Emergency and Critical Care Medicine, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima City, 770-8503 Japan.
authors.forename: Masaji
authors.initials: M
authors.lastname: Nishimura