Impact of Various Decontamination Methods on Performance of Personal Protective Equipment (PPE)
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Contributing OfficeCenter for Devices and Radiological Health
Abstract
During the SARS-CoV-2 pandemic, many methods of decontamination were proposed to combat the severe shortages of disposable personal protective equipment (PPE) for healthcare workers. Due to the shortage of available PPE for testing, the effectiveness or impact of many of these methods on N95 respirators remained inconclusive. As a result, several methods did not receive approval by the FDA for emergency use authorization (EUA). The main concerns for decontamination of disposable PPE are two-fold. Firstly, the method must adequately decontaminate the PPE, and secondly the equipment must still meet its performance requirements after decontamination. For respirators, this performance requirement entails filtration, pressure drop and fit testing and for gowns this entails liquid penetration tests. For this work, we first performed extensive review and identified numerous decontamination methods and procedures intended for use on disposable N95 respirators and/or isolation gowns. Then, we developed exclusion criteria to determine which methods were worth pursuing. These criteria eliminated common methods already approved by FDA EUAs, such as vaporized hydrogen peroxide decontamination, and eliminated overly complex methods requiring hard to obtain materials or multi-step processes. We concluded that single step decontamination methods of respirators that were worth pursuing were microwave generated steam decontamination, autoclave sterilization, and gaseous ozone decontamination. Other methods seemed promising and may later be pursued if materials become available, such as, cold plasma decontamination. These decontamination methods were also determined to be applicable to gowns except for microwave generated steam decontamination. Additionally, decontaminated N95 respirators should also pass filtration efficiency, pressure drop, and fit requirements stipulated by Center for Disease Control and Prevention (CDC) and Occupational Safety and Health Administration (OSHA). Isolation gowns must also meet established criteria. Liquid penetration resistance is to be determined by the established methods of the AATCC 42 spray impact test, the AATCC 127 hydrostatic head test, and the ASTM F1670/F1671 soils resistance tests. We are performing feasibility tests to ensure the decontaminated respirators and isolation gowns retain the required performance characteristics up to 5 decontamination cycles. The fit factor testing will be conducted with an elastomeric manikin head, filtration efficiency testing with sodium chloride aerosol spray consistent with CDC’s protocol for filtration testing, and pressure drop measurement using sensitive pressure transducers. This work will develop our understanding of infrequently evaluated decontamination techniques and their impact on medical personnel’s disposable PPE if shortages were to occur in future pandemics.