Water content of delivered gases during non-invasive ventilation in healthy subjects

Lellouche F, Maggiore SM, Lyazidi A, Deye N, Taillé S, Brochard L

In this study the authors measured hygrometry during non invasive ventilation (NIV) delivered to healthy subjects with different humidification strategies: heated humidifier (HH), heat and moisture exchanger, (HME) or no humidification (NoH). They found that during NIV, with NoH, gas humidity was very low when an ICU ventilator was used, but equivalent to ambient air hygrometry with a turbine ventilator at minimal FiO2 was used.


HME and HH had comparable performances, but HME’s effectiveness was reduced with leaks. During CPAP, dry gases were less tolerated than humidified gases. Comfort data suggest that levels above15 mgH2O/l is well tolerated. In favourable conditions, HH and HME’s are capable of providing such values, even in the presence of leaks.


Intensive Care Medicine 2009; 35: 987 – 995


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