The hospital vacuum cleaner: mechanism for redistributing microbial contaminants.

Carpeting patient care units in acute care hospitals is increasingly common. While the safety of carpeting has been heavily debated, there has been little epidemiological data to document risk to the hospitalized patient. With the report of a two-year study documenting human contamination and potential colonization by microorganisms spread from hospital carpeting, a need was established to document modes of transmission. The objective of this study was to define the potential of hospital vacuums for dispersing particles of a size comparable to the microbial cell. Both filter efficiency and vacuum exhaust turbulence are evaluated. Results document that of eight units claiming high efficiency filtration, none was capable of meeting advertising claims. In addition, exhaust air velocities for one unit reached 175 feet per minute at 30 inches above the floor.