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Study finds enhanced engineering and administrative controls needed in sterile processing units


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Washington — Current NIOSH and industry regulations and professional guidelines aimed at preventing unintentional exposure to pathogens during the sterile processing of medical devices may not be sufficient to ensure provider and patient safety, results of a recent study suggest.

“Guidelines and standards define the optimal processing environment as a two-room unit with physical separation and unidirectional workflow between dirty and clean activities, or at least 4 feet of separation between the dirty and clean areas in a one-room design,” researchers from the independent research company Ofstead & Associates write.

The study builds off previous research conducted by researchers at Ofstead showing that workers who process reusable medical instruments and equipment may be regularly exposed to tissue, blood and bodily fluids from patients – even when wearing personal protective equipment. The researchers next wanted to identify processing activities that generate splashes, characterizing splash amount and dispersal patterns in manual cleaning areas, evaluating visitor splash exposure, characterizing the impact of practices and equipment on splash generation, and assessing PPE effectiveness at preventing exposure during routine activities.

To do so, the researchers affixed moisture-detection paper to PPE and various surfaces in a new sterile processing unit in a large urban academic medical center. The three-room unit was designed to reduce the risk of cross-contamination and optimize processing outcomes. Findings show that manual cleaning generated droplets that were detected on the floor more than 7 feet away from the processing sink, while transporting wet endoscopes dispersed droplets on a 15-foot path from the sink to the automated reprocessor.

Additionally, extensive droplets were discovered on PPE worn by technicians at the sink and observers 3-4 feet away. Shoe covers and transport cassettes also tracked fluids throughout the unit.

Other recent studies, the researchers note, illustrate the potential for contamination from clinically used medical devices to spread throughout processing areas and expose personnel and processed devices. For instance, during a study of fully processed duodenoscopes, researchers detected microbes and “high-concern organisms” on 65% and 5%, respectively, of the more than 1,700 samples. Environmental sampling detected Staphylococcus, Acinetobacter and Pseudomonas in processing sinks and on floors, and 63% of the high-concern organisms found on these samples were detected in patient-ready duodenoscopes, suggesting that the environment contaminated the endoscopes, or vice versa.

According to a special report issued in June by the Centers for Disease Control and Prevention, antimicrobial-resistant infections during hospitalization rose at least 15% from 2019 to 2020. Specifically, Acinetobacter infections rose 78%.

These bacteria also could contaminate medical devices after sterile processing and expose patients to dangerous infections. Better engineering and administrative controls, the Ofstead researchers say, are needed and can include single-use medical devices that don’t require processing and closed systems that contain and automate manual cleaning. Redesigning devices, such as probes that don’t require rinsing under running water and transport cassettes that don’t drip, could reduce the risks and burdens of manual cleaning.

The latest Ofstead study was published online in the American Journal of Infection Control.

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