Journal of the American College of Surgeons study authors report a framework to address supply limitations and enhance safety of healthcare workers by returning their disinfected N95 masks to them for reuse

Amid shortages of personal protective equipment due to the Coronavirus Disease 2019 (COVID-19) pandemic, a St. Louis healthcare system has implemented a process to disinfect disposable N95 respirator masks that allows healthcare workers to reuse their own mask for up to 20 cycles. The novel disinfection process, developed in collaboration with Washington University School of Medicine, uses vaporised hydrogen peroxide and is described in an “article in press” on the Journal of the American College of Surgeons website.

Test results from a pilot programme at Barnes-Jewish Hospital and two other hospitals that are also part of BJC HealthCare, showed that the disinfection process kills germs from N95 masks while ensuring that the only person who touches the mask is the original mask wearer, study authors reported.

Their programme uses a disinfecting procedure first tested by Duke University researchers in 2016. However, the Barnes-Jewish process has a unique modification—an identification system that enables the hospital to return the sanitised mask to the same individual each time, said senior author Shaina Eckhouse, MD, FACS, assistant professor of surgery at Washington University School of Medicine, St. Louis. Dr Eckhouse is part of the multidisciplinary team of university and hospital staff who developed the disinfection program.

This approach, according to the authors, increased employee acceptance of reusing what is normally a single-use N95 mask and helped ensure proper fit of the returned mask.

In late March, before the programme began, Barnes-Jewish had a low inventory of N95 masks—about a week’s worth—and no expectations for replenishment because of international shortages in hospital supply chains, according to study coauthor Andrew Pierce, MHSA, director of supply plus at Barnes-Jewish.

The disinfection process that has since been put into place begins at the end of a shift.  A healthcare provider removes his or her N95 mask in that unit’s soiled utility room and places it in a sterilisation pouch (Crosstex) made of breathable polyethylene fibre (Tyvek by DuPont) on one side. On the other side of the sealed pouch, the worker writes his or her name or employee ID number, hospital, department, and unit location and puts the pouch in the soiled collection bin.

A designated worker wearing proper protection collects the bins twice a day and takes them to a specially designed and sealed disinfection room. There the pouches are arranged, breathable side up, by clinical unit on wire racks. A hydrogen peroxide vapour generator (Bioquell Z-2), which Washington University already owned to decontaminate equipment, fills the room with the chemical.

After 4.5 hours of disinfection, a worker moves the racks of masks to another area that has a fan to offgas the hydrogen peroxide, where the masks stay until sensors record a zero reading. The pouches are returned to their respective units in a decontaminated bin, finishing a process that takes about seven hours, Pierce said.

Workers can wear their mask up to three weeks because past studies show that disinfection more than 20 times could alter the fit of the mask, he noted.

Pierce says they are disinfecting 240 N95 masks a day and have the capability of disinfecting 1500 masks daily.

Without the disinfection program, he said the healthcare system would need to discard a substantial amount of its respirator masks. Because of the disinfection, the hospitals now have enough masks to last for weeks.  

Eckhouse said other hospitals facing mask shortages can reproduce the disinfection programme if they bring together experts in environmental health and safety, medicine, and facility management. “Having the infrastructure already in place would improve the ease of deploying an N95 disinfection process,” she stated.


Reference: Pierce
A, et al. Institution of a Novel Process for N95 Respirator Disinfection
with Vaporized Hydrogen Peroxide in the setting of the COVID-19 Pandemic at a
Large Academic Medical Center. Journal of the American College of Surgeons,
2020; 10.1016/j.jamcollsurg.2020.04.029