Breathing filters are becoming a standard tool used in the hospital environment to combat the possibility of the spread of nosocomial infection in ventilated patients around the world.This review includes an update on current thinking concerning breathing filters, a re-evaluation of currently used terminology and correct validation and use of product, as viewed from a manufacturers perspective. Perhaps the two main issues this presentation attempts to draw attention to includes challenging the traditional models describing the way breathing filters function as well as discussing the prefered test protocol by which breathing filters can be evaluated in terms of bacterial and viral efficiency.

        Key words: current terminology – traditional models of filter’s function – test protocol