The effect of humidification on the incidence of ventilator-associated pneumonia.

Breathing systems used with heated humidifiers are associated with a rapid and high level of bacterial colonization. This colonization is considerably reduced with the use of HMEs. Breathing systems do not need to be changed during the entire ventilation period of a given patient unless they are visibly soiled or mechanically malfunctioning. The incidence of VAP is not influenced by the type of humidification device (heated humidifier or HME). The incidence of VAP is not affected by the duration of use of HMEs or the type of HME, but prolonging the use of a HME further reduces the risk of cross-contamination and results in considerable cost savings.