Can clean-room particle counters be used as an infection control tool in hospital operating theatres?

Current UK guidelines for the commissioning of hospital operating theatres rely on air-flow checks, identification of "short-circuits" and measurement of airborne microbiological levels under design conditions when the theatre is idle. There is currently no guideline for infection control teams to investigate theatres when an increased infection risk is suspected. This study aims to examine the use of clean-room particle counters as an infection control tool by monitoring particle profiles in air as a surrogate for infectious particles. Particle counters (three- and six-channel) were used to simultaneously measure particle concentrations at the theatre inlet area, two outlets and bed area, under design and working conditions. A significant increase in particles of all size ranges (0.3 to >10μm diameter) was observed when people were introduced. Particle distribution was uneven, with response to environmental changes different at the two outlets. Removal efficiency varied from 52-100%, due to the introduction of particles to the theatre. Within the bed area, significantly different concentrations were measured under design and working conditions; corresponding microbiological samples indicated an associated increase in airborne bacteria. We concluded that particle counters can be used in some aspects of infection control, although more studies are required to fully explore their potential.