Infection potential of nondisposable pressure transducers prepared prior to use

This study was designed to examine whether pressure transducer systems prepared hours or days before actual use represent an infection potential. Twenty-one nondisposable transducers assembled with sterile plastic disposable domes and extension tubing were utilized. The systems were prefilled with heparinized flush solution (2 U sodium heparin per ml normal saline). Flush solution samples were cultured from the distal end of the equipment immediately after set-up (time 0) and 24, 48, and 72 h after set-up in all 21 transducers. In 11 of 21 transducers, cultures were also taken at 168 h (1 wk) and 336 h (2 wk) after set-up. Out of the total 106 cultures, only two showed growth, both of which proved to be external skin or mouth contaminants. Binomial distribution testing indicated that if a .05 probability level was used, the chance was 1.3% that one or more transducers in 100 could become contaminated by 72 h. Using the same statistical analyses for the 66 cultures involving the 11 transducers cultured for 2 wk, the chance of contamination in 100 cultures is 2.7% at 2 wk. We conclude from these data that nondisposable transducer systems, when preassembled using standard aseptic precautions and sterile disposable plastics, show no evidence of significant contamination when allowed to stand in readiness after assembly but not connected to a patient. We feel it is safe to preassemble transducers for at least a 72-h period before use. Longer intervals from set-up to use may also be justified.