Potential Spread Via Droplets from Dirty to Clean Instruments
ECRI: ‘We had users who got stuck in their gowns’
“Droplets were documented up to 7.2 feet from the sink,” the authors reported. “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 four feet of separation between the dirty and clean areas in a one-room design.”2-4
For sites able to consider new construction, separating the unit into multiple rooms, increasing the square footage to allow for more separation, and incorporating barriers could help reduce splash exposure, they recommended.
Although researchers used clean equipment, normally “sterile processing personnel decontaminate medical devices that are heavily soiled with blood, tissue, and secretions,” the authors noted. “Contamination may spread throughout processing areas, potentially exposing personnel and patient-ready devices, especially when there is insufficient separation between the dirty and clean areas.”
Sterile processing workers participating in the experiment wore the full regalia of personal protective equipment (PPE), but there is concern they could contaminate themselves during doffing and potentially touch a mucous membrane, such as the eyes or nose. Researchers also found a common breach in PPE.
“When they use a spray arm to spray off instruments, [it] generates splash,” said Cori Ofstead, MSPH, president and CEO of Ofstead & Associates, a healthcare research and consulting firm in Bloomington, MN, at the 2023 conference Association for Professionals in Infection Control and Epidemiology (APIC). “We rinsed out a stainless-steel basin, which would be grossly contaminated, but [for the study] it was sterilized. We [saw] droplets four feet away on a cart, six feet away on the wall, and on the floor — seven feet away from the sink.”
For the droplet research, these cleaning activities were performed once each. “In a normal session, they’re not going to clean one probe or one scope or one stainless steel instrument — they’re going to do a few, dozens, or hundreds of them,” she said.
Ofstead and colleague Krystina Hopkins, MPH, a research manager at Ofstead & Associates, have authored two papers on their research, and some of those findings were the basis of their APIC presentation.
“The origin of this three-foot separation recommendation was an outbreak investigation involving multidrug-resistant Pseudomonas aeruginosa that infected 36 patients in Canada,” Hopkins said. “[Overall,] 12 deaths [were] attributed to the infection. Investigators found contaminated sink drains in intensive care rooms. Although this investigation did not involve instrument reprocessing areas, the findings have been used to support the recommendation that three feet of separation between dirty, wet areas and clean, dry areas is sufficient.”5
But according to these new findings, that does not seem to be the case. The manual cleaning process used for contaminated instruments involves immersing them in water with detergent and scrubbing, brushing, and spraying to remove residual blood and tissue. The PPE worn typically includes gowns, gloves, face masks, eye protection, head coverings, and shoe covers. To identify droplets and splashes, the researchers used water detection sheets — a blue paper that turned white when wet. These were attached to the workers and placed in different areas of the decontamination room.
The experiment revealed a chink in the PPE armor, as droplets landed in the exposed neck area beneath the face shield. As the workers leaned over the sink while cleaning equipment, droplets and splatter contaminated their necks and lower face.
“I’m concerned about this because most of the sterile processing techs we encounter are not wearing a mask with any fluid resistance,” Ofstead said. “They don’t change those masks very often.”
Workers tried a face shield with an expandable neck cover during the experiment, but it was not practical for those who wore glasses (i.e., fogging and discomfort).
Most cleaning activities caused dispersion of droplets, beginning with filling sinks with faucets that are placed directly over drains.
ECRI: Gown Tears and Leaks
At another session at APIC 2023, the Emergency Care Research Institute (ECRI) updated its ongoing research into tears, strikethroughs, and leaks in medical gowns.
“In the past few years, we’ve noticed through ECRI’s problem reporting system, from our member hospitals, that we are still seeing a lot of [gown] leakage, tearing, and contamination,” said Karen Haberland, MS, senior project officer at ECRI. “We know that this problem hasn’t gone away, and we really want to work on improving PPE.”
After receiving a lot of questions and comments, ECRI is conducting ongoing research on a common Class I gown called “disposable, non-woven, level two isolation gowns.” Gowns of this type from a variety of manufacturers are being put through a series of comparative tests.
“We brought in experienced users, people who use isolation gowns on a daily basis,” Haberland said. “They wore the gowns for a period of time, and we put them through some different activities. Then we had them rank each of the gowns against each other.”
ECRI is using fluid barrier testing technology that includes hydrostatic pressure testing — a column of pressurized water to see if any drops come through the gown material. “This testing was all performed with water,” Haberland noted. “Bodily fluids have a lower surface tension than water and they’re usually warmer, which could make them more likely to strike through than water.”
The gown tests are ongoing, but Haberland identified failure at the gown seams as one problem. “If you have [a gown with] sewn seams, you really want to make sure that they’re covered in a film or a tape to eliminate the possibility of them failing,” she said. Some of these disposable gowns are designed to be simply torn off after use but tearing beyond the designated areas occurred frequently.
“Unfortunately, every gown had at least a couple of issues with tearing during removal,” Haberland said. “Instead of breaking at their designated ties or perforations, where they’re supposed to, they would rip down the front. We had users who got stuck in their gowns. The front half of the arm would rip off and they’d still have half the gown on. That would be really bad for contamination of our scrubs. We need to work with manufacturers to improve this issue, but we also need to make sure that we’re training our staff to doff properly to make sure these things don’t happen.”
- Ofstead L, Hopkins KM, Daniels FE, et al. Splash generation and droplet dispersal in a well-designed, centralized high-level disinfection unit. Am J Infect Control 2022; Sep 15: S0196-6553(22)00629-0. doi: 10.1016/j.ajic.2022.08.016. [Online ahead of print].
- Day LW, Muthusamy VR, Collins J, et al. Multisociety guideline on reprocessing flexible GI endoscopes and accessories. Gastrointest Endosc 2021;93:11-33.
- Association for the Advancement of Medical Instrumentation. ANSI/AAMI ST91: 2021 Comprehensive guide to flexible and semi-rigid endoscope processing in health care facilities. https://www.aami.org/st91
- Van Wicklin SA, Conner R, Spry C. Guideline for processing flexible endoscopes. In: Guidelines for Perioperative Practice. Association of periOperative Registered Nurses (AORN);2017.
- Ofstead CL, Hopkins KM, Smart AG, Brewer MK. Droplet dispersal in decontamination areas of instrument reprocessing suites. Am J Infect Control 2022;50:126-132.
Infection preventionists may want to recheck the distance between the separation of dirty and clean activities in cleaning and reprocessing rooms after researchers found contaminated droplets can travel more than seven feet.
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