7 Failure Rates during Reuse of Disposable N95 Masks in Clinical Practice in the Emergency Department

Abstract

Study Objectives The COVID-19 pandemic caused a worldwide shortage of personal protective equipment, specifically disposable N95 respirators, prompting health care entities to extend the use of these masks beyond their intended single-use manufacturer recommendation with a paucity of supporting research. We sought to explore the failure rate when reusing single-use N95 respirators through repeated fit testing in an emergency department (ED). Methods We performed a prospective cohort study of ED personnel (“subjects”) required to use respirators at an academic, level one trauma center. All investigators performing fit testing reviewed OSHA qualitative fit test guidelines and training and were familiar with the testing protocol. All subjects had been previously fit tested and assigned an appropriately sized N95 mask by employee health per hospital protocol. Subjects who failed initial fit testing and those who declined to participate were excluded. Per study protocol, subjects were fit tested periodically throughout their shifts and on multiple shifts over the 8-week study period. Data points collected included the age of the mask, subjective assessment of mask seal quality, and fit test results. The data was analyzed using Fisher’s exact test, and odds ratios were calculated to determine the failure rate of disposable N95 masks following reuse. The study was approved by the Institutional Review Board. Results One hundred thirteen disposable N95 masks were evaluated. Twenty-eight masks were in their first day of use (3 failures), 29 were in their 2nd day of use (2 failures), 26 were in their 3rd day of use (9 failures), 11 were in their 4th day of use (5 failures) and 21 were in their 5th or greater day of use (10 failures). Categorizing the masks into those being used for 2 or fewer days versus those being used for 3 or more, the odds ratio for mask failure with an older mask was 7.1 (confidence interval 2.5-20, p<0.0001), with younger masks failing 9% of the time and older masks failing 41% of the time. Conclusion Disposable N95 masks have significant failure rates following reuse in clinical practice.