Bacterial and viral removal efficiency, heat and moisture exchange properties of four filtration devices.

Four devices used for filtration of microorganisms and/or for heating and moistening the ventilated air during mechanical ventilation were evaluated. This evaluation included measurement of bacterial and viral removal efficiency, heat and moisture exchange properties, dead space and air flow resistance. The devices included: Pall BB50T and DAR Sterivent (filtration devices); DAR Hygrobac and Gibeck Humid-vent [heat and moisture exchangers (HMEs)].