Humidification and secretion volume in mechanically ventilated patients

Respir Care. 2009 Oct;54(10):1329-35.


Objective: To determine potential effects of humidification on the volume of airway secretions in mechanically ventilated patients.

Methods: Water vapor delivery from devices providing non-heated-wire humidification, heated-wire humidification, and heat and moisture exchanger (HME) were quantified on the bench. Then, patients requiring 24-hour mechanical ventilation were exposed sequentially to each of these humidification devices, and secretions were removed and measured by suctioning every hour during the last 4 hours of the 24-hour study period.

Results: In vitro water vapor delivery was greater using non-heated-wire humidification, compared to heated-wire humidification and HME. In vivo, a total of 9 patients were studied. Secretion volume following humidification by non-heated-wire humidification was significantly greater than for heated-wire humidification and HME (P=.004).

Conclusions: The volume of secretions appeared to be linked to humidification, as greater water vapor delivery measured in vitro was associated with greater secretion volume in vivo.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aerosols
  • Aged
  • Female
  • Humans
  • Humidity*
  • Male
  • Middle Aged
  • Nebulizers and Vaporizers*
  • Respiration, Artificial / adverse effects*
  • Respiration, Artificial / instrumentation*
  • Sputum / metabolism*


  • Aerosols