Droplet Dispersal in Sterile Processing Units Exceeds Limits Droplet Dispersal in Sterile Processing Units Exceeds Limits

In the era of Ebola, COVID-19, and even Legionnaires, technicians and other staff working behind the scenes to ensure provider and patient safety continue to face a long-recognized but under addressed challenge: splashes and airborne droplets.

Granted, National Institute for Occupational Safety and Health (NIOSH) standards, industry standards, and professional guidelines are all in place to prevent unintentional exposure to pathogens. However, findings from a newly published study in the American Journal of Infection Control suggest they fall short.

In the study, researchers found that simulated manual cleaning of medical devices generated a drenching splash throughout the process with droplet dispersal exceeding 7 feet (2.1 meters).

Cori Ofstead

“The guidelines say that droplets stop at 3 or 4 feet and they don’t,” Cori L. Ofstead, MSPH, lead author and president/CEO of Ofstead & Associates, Bloomington, Minnesota, told Medscape Medical News. “That’s the problem with having standards and guidelines that are not based on relevant evidence, [which] in this case, is a single study that was done in an intensive care area where they had an infection outbreak.”

Ofstead was referring to a 2009 report in the journal Infection Control and Hospital Epidemiology detailing a Canadian investigation involving a multidrug-resistant Pseudomonas aeruginosa outbreak in an ICU. The report implicated the faucets over the hand hygiene sinks, with fluorescent dye showing droplet dispersal roughly 3 feet away from the sinks.

“Somehow it [the 3-feet rule] got implemented in guidelines in sterile processing decontamination areas, which are not the same as hand hygiene,” Ofstead explained.

With a goal of providing more current evidence on droplet generation and dispersal, as well as  personal protection equipment (PPE) exposure/effectiveness, she and her colleagues simulated manual cleaning of a decommissioned colonoscope and transvaginal ultrasound probe, using for the study location a new academic sterile processing unit.

Study site set-up. A) layout of 3-room centralized high-level disinfection unit. B) Decontamination sink with blue moisture detection paper, carts simulating observers, and distance labels. C) Sink set-up and blue moisture detection paper.

To detect droplet generation and dispersal as well as splash following common technician activities (eg, colonoscope brushing, scrubbing, rinsing and transport to an automated endoscope reprocessor [AER] for sterilization), the researchers affixed blue moisture-detection paper to environmental surfaces, on carts positioned 4 feet (1.2 meters) from the sink (to simulate observers), and along a 15-foot pathway between the sink and AER.

They observed droplets everywhere.

Technician activities such as running the faucet and rinsing the probe under running water generated substantial splashing overall. Instrument rinsing in particular produced small and large droplets and confluent puddles of water around the sink and in the broad area surrounding the workspace. Droplets were also dispersed on the floor 7.25 feet (2.2 meters) away and along the entire 15-foot path from the sink to the AER.

At the sink, the technician risked drenching exposure from head to toe during most activities, and even observers positioned 3-4 feet away were found to have droplets on their gowns. In addition, saturated shoe covers reportedly tracked moisture away from the sink to the unit door — a distance of 13 feet (4 meters) — and 2 feet (0.6 meters) farther out into the PPE foyer for donning and doffing.

Although PPE gowns effectively repelled moisture during cleaning of a single device, Ofstead emphasized that technicians typically handle up to 10 instruments during a normal, 2-hour shift, further increasing exposure risk with each subsequent cleaning.

However, perhaps one of the most surprising findings was that despite an optimal unit design, including physical separation of clean and dirty activities and pressurized air flow to protect workers, droplets were still broadly dispersed.

Splash 2.0 — Placing Technicians First

Current efforts, however well-intentioned, might not be offering the degree of protection (and consideration) that sterile processing technicians need.

Dr Stella Hines

“The study was conducted in a new sterile processing area that had an extra excellent kind of distancing and three separate rooms, something that I think most of our hospitals are working toward,” Stella Hines, MD, assistant professor at the University of Maryland School of Medicine in Baltimore, told Medscape Medical News. Dr Hines was not directly involved in the study.

“But it also really kind of highlighted what’s happening to workers potentially,” she added. “For example, we want to know if that spray or splatter has a live microbe it in that could cause a problem or…in a highly wet environment, if that water has some kind of chemical in it that could pose an occupational hazard to the worker based on skin or mucous membrane exposure.”

Ofstead agreed. “We need to be thinking about the exposure of critically important workers and the environment in an era where we are worried about aerosol-generating procedures and superbugs,” she explained.

Hines and Ofstead also noted that the majority of staff involved in front-line patient care have never actually ventured into the sterile processing units, nor do they recognize the risks that technicians working in these units face on a daily, or even hourly, basis.

“The people who run these operations are very well trained and knowledgeable. I think that it would be helpful for them to know that they’re appreciated, and for the people upstairs on the front lines using the equipment to see what goes on downstairs and all of the painstaking steps that need to be in place for the equipment to come out of sterile processing and be ready to go, said Hines.”

In the meantime, hospital leaders need to address the challenges and danger posed by migrating infectious droplets, especially for workers involved in processes that stir them up in the first place — workers who by the end of their shifts are unavoidably drenched with infectious blood and tissue secretions.

“I think that it’s going to take a much bigger kind of worldview from hospital leadership,” Hines said.

The study was supported in part by a grant from Healthmark Industries. Ofstead reports research grants or consulting fees through her organization with 3M Company, Ambu, Boston Scientific, Cleanis, Fortive/Advanced Sterilization Products, Healthmark Industries, Pentax, and Steris/Cantel/Medviators. Hines reports no relevant financial relationships.

Am J Infect Control. Published online October 12, 2022. Full text

Liz Scherer is an independent journalist specializing in infectious and emerging diseases, cannabinoid therapeutics, neurology, oncology, and women’s health.