Alternative Qualitative Fit Testing Method for N95 Equivalent Respirators in the Setting of Resource Scarcity at the George Washington University

Abstract

The 2019 Novel Coronavirus has caused an acute shortage of personal protective equipment (PPE) globally as well as shortage in the ability to test PPE such as respirator fit testing. This limits not only the ability to fit PPE to medical practitioners, but also the ability to rapidly prototype and produce alternative sources of PPE as it is difficult to validate fit. At the George Washington University, we evaluated an easily sourced method of qualitative fit testing using a nebulizer or "atomizer" and a sodium saccharin solution in water. If aerosolized saccharin entered candidate masks due to poor fit or inadequate filtration, then a sweet taste was detected in the mouth of the user. This method was tested against previously fit tested Milwaukee N95 and 3D Printed Reusable N95 Respirator as a positive control. A Chinese sourced KN95, cotton cloth material, and surgical mask were tested as other masks of interest. Sensitivity testing was done with no mask prior to fit test. A sweet taste was detected for both the surgical mask and cotton cloth, demonstrating a lack of seal. However, there was no sweet taste detected for the Milwaukee N95, 3D Printed Reusable N95 Respirator, or Chinese KN95. These results demonstrate this could be a valuable methodology for rapid prototyping, evaluation, and validation of fit in a non-clinical environment for use in creation of PPE. This method should be not be used without confirmation in a formal qualitative or quantitative fit test but can be used to preserve those resources until developers are confident that potential new N95 comparable respirators will pass. We strongly suggest validation of masks and respirators with Occupational Safety and Health Administration (OSHA) approved fit testing prior to use in a clinical environment.

Biosafety materials: an emerging new research direction of materials science from the COVID-19 outbreak

“…When respiratory infectious diseases are prevalent and when working in a polluted environment such as a dusty area, wearing a mask is necessary to keep workers safe. 144,145 Novel material fabrication technology such as 3D printing has been applied to manufacture masks. 146 The N95 filtering facepiece respirator was custom designed for medical staff.…”

Can we use these masks? Rapid Assessment of the Inhalation Resistance Performance of Uncertified Medical Face Masks in the Context of Restricted Resources Imposed during a Public Health Emergency

“…The shortage of masks that resulted as a consequence of previous epidemics has focused attention upon the testing of the filtration efficiency of home-made or uncertified masks and respirators made from different materials (Cooper et al 1983;Rengasamy et al 2010;Jung et al 2013;Konda et al 2020). Likewise, the re-use performance of the masks or respirators after some form of cleaning or sterilization (Viscusi et al 2009;Liao et al 2020) and alternative qualitative mask fit testing methods (Provenzano et al 2020) have been studied. However, very little consideration has been given to devising rapid, scalable emergency protocols to help assess the performance of replacement, alternative masks or respirators, during the critical initial stages or beyond, in situations where emergency-use authorisation has been given due to the scarcity of supply.…”