Technique To Reprocess N95 Masks Safely Up To 20 Times Each

Only recently, the Barnes-Jewish hospital in St. Louis, Missouri had only one week’s supply of N95 masks and no expectation for replenishment due to international shortages. To overcome this challenge, it collaborated with the Washington University School of Medicine to implement a method to disinfect and reuse N95 masks up to 20 times each. The method utilizes vaporized hydrogen peroxide (VHP) as a disinfectant and ensures that the healthcare workers receive their own masks back after disinfection. The approach can help reduce the demand for protective masks and allow hospitals to operate on limited supplies.

The team developed the new method based off one created in 2016 at Duke University, with the key improvement being that each healthcare worker received their own disinfected mask from the prior day.



The process begins with the healthcare worker, at the end of their shift, removing the mask and placing it into a sterilization pouch, writing their name, id, and other identifying information on the pouch and placing it in a soiled collection bin. A designated worker, wearing proper protection, gathers the collection bins twice a day and takes them to a specially designed, sealed disinfection (VHP) room.



The pouches are arranged, and a hydrogen peroxide vapor generator (Bioquell Z-2) fills the room with decontaminating hydrogen peroxide vapor. The disinfection takes 4.5 hours, after which a worker moves the racks of masks to another area to offgas hydrogen peroxide with the help of fans. The masks stay in this room until sensors no longer detect hydrogen peroxide in the air. The pouches are then returned to their respective hospital units. The whole process takes about 7 hours total and can be repeated about twenty times. The researchers found that after 20 disinfection cycles the masks no longer fit well.



“Our primary outcome is safety for the health care worker,” said project leader and study coauthor Andrew Pierce, MHSA, director of supply plus at Barnes-Jewish. “We want to make it safer for team members who are at risk while taking care of patients with a known or possible COVID-19 diagnosis. This program is a welcome improvement for extended usage of N95s during the shortage that we are facing.”

The pre-proof paper at Journal of American College of Surgeons: 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

Source