Possible role of vacuum systems and compressed air generators in cross-infection in the ICU. A radioactive tracer study.

Cross-contamination between a hospital's vacuum and compressed air systems was demonstrated using xenon-133 as a tracer. A xenon-133 bolus was introduced to the vacuum system in the intensive care unit. Calculations based on the amount of radioactive tracer recovered from the compressed air outlet at the same location as that at which the tracer was introduced indicated that 17% of the tracer had entered the compressed air system. The contamination was caused because the vacuum and compressed air systems were located in the same machine room. This could conceivably provide a route for respiratory tract contamination in patients receiving ventilatory assistance with air-oxygen mixtures.