Droplet Dispersal Study Draws Mixed Reviews

In a recent study to see the behavior of visible droplets in a controlled environment, it was noted that visible droplets seemed to cover much of the surrounding area. In fact, those droplets splattered all over reusable instruments and equipment in the simulation.

What’s worse, those droplets traveled as as 5 feet away from the sink! In essence, the water droplets recontaminated nearly all of the equipment (which had been cleaned before the simulation) within a five foot radius. 

Moreover, the PPE that the technicians were wearing did NOT prevent the water droplets from getting on their skin during the simulation.  This is in spite of that fact that they were wearing the PPE in the approved and appropriate manner. 


In addition, the personal protective equipment technicians used during the simulation did not prevent liquids from splashing onto skin, even when donned and doffed properly.

“We had heard that sterile processing departments were not being prioritized for supplies of high-quality PPE due to COVID-related supply-chain issues. They were having to reuse PPE and attempting to use components that were not fluid-resistant or did not fit properly enough to provide protection,” lead investigator Cori L. Ofstead, MSPH, the president and CEO of Ofstead & Associates, a research group based in St. Paul, Minn., told Priority Report

Ms. Ofstead and her co-investigators affixed droplet detection paper onto various surfaces in a hospital’s sterile processing department, adjacent to sinks and at varying distances from sinks (Am J Infect Contr 2022;50[2]:126-132). They also affixed droplet detection paper to single-use PPE, such as head covers, gowns, face masks, shoe covers and gloves. Sterile processing technicians simulated medical instrument reprocessing tasks, such as filling the sink, placing a ureteroscope into water, brushing the lumen, rinsing a stainless steel basin with a power sprayer, and using a sonication system within a multiple-basin sink. Technicians donned new PPE as needed whenever their garments were splashed. Before any work began, Ms. Ofstead’s team reported, technicians had thoroughly disinfected all work areas and medical instruments.

Power spraying generated the most splash, with substantial splatters 5 feet from the sink. But almost every task generated detectable droplets, often more than 3 feet away from where the activity occurred and on multiple surfaces, as well as on the PPE and skin of technicians. Using the sonication sink did not produce any detectable droplets.

“Droplets were generated by every activity no matter how carefully it was done,” Ms. Ofstead said. “I was surprised to see so many droplets on so many surfaces several feet from the sink.”

Although Ms. Ofstead noted that this was a hypothesis-generating project that needs to be validated, she suggested the data are already strong enough to encourage sterile processing leaders to think about ways to reduce the potential of splash exposure, such as installing clear plastic barriers or a sink hood.

Translating to Real-World Scenarios

“I am really skeptical overall about these kinds of studies using models rather than real-life situations,” said Harish K. Gagneja, MD, FACG, AGAF, FASGE, a gastroenterologist with Austin Gastroenterology, in Texas. “These aerosols don’t mean much as they are not coming directly from the patient.” The aerosols could originate from the scope but also from the washing fluid, he said.

In Dr. Gagneja’s view, the only way to know if the droplet dispersal measured in the study leads to sickness is to compare rates of infection between healthcare personnel who routinely reprocess scopes and those among other healthcare workers.

“There are people who are processing the scopes day in and day out. Are they getting sicker than those who are not?” Dr. Gagneja asked.

Ms. Ofstead responded that symptomatic illness may not be the best measure of exposure. It could be that sterile processing technicians have stronger immune systems due to more frequent exposure to diverse microbes, and end up hosting pathogens that can infect other people with less robust immune systems. This is a hypothesis that needs further research, she added.


“I’ve been in GI and endoscopy nursing for about 20 years, so I see how much more we do than we used to,” said Emily Salisbury, BSN, RN, the director of clinical operations for Endoscopy Services at University of Utah Health, in Salt Lake City. When her career began, Ms. Salisbury said, using full PPE was not common during reprocessing but has long since become routine.

Ms. Salisbury also noted that there are some safeguards in place in endoscopy units, such as marks in a sink to indicate how high to fill the basin. Some of the splashing seen in this study would likely not happen in everyday reprocessing units, she noted.

“I think there needs to be a realistic view,” Ms. Salisbury said, adding that sink hoods would be much more feasible than adding plastic barriers to a crowded sterile processing suite.

Ms. Salisbury agreed with Ms. Ofstead that PPE for sterile processing technicians was an afterthought during the worst of the COVID-19 pandemic. “I thought that was a very valid point,” she said. “Maybe the people who do reprocessing weren’t considered when we were distributing PPE.”