P2/N95 filtering facepieces (FFP) are medical products designed to minimize the transmission of airborne diseases in healthcare settings. To be effective, a tight seal has to form between the FFP and the user’s face. The gold standard for assessing the adequacy of fit is with fit testing. Quantitative fit testing is an objective test which uses a machine such as a PortaCount to sample the number of microscopic particles within the FFP and in ambient air. An overall fit factor is calculated by the machine by comparing the ratio of particles within the FFP and in ambient air over the duration of the test.
Previous studies from overseas have found that certain FFPs are more likely to pass fit testing than others. However, there are no studies comparing different P2/N95 FFP using quantitative fit testing in an Australian healthcare setting. This is significant because health services may purchase large quantities of FPPs to find that the particular FFP does not fit a large proportion of Australian healthcare workers. If all the P2/N95 FFP pass fit testing equally, then secondary factors such as ease of donning/doffing and comfort may be used to guide purchase of P2/N95 FFP.
The aim of this observational study is to compare the pass rate of four different brand and styles of P2/N95 FFP in an Australian healthcare setting using quantitative fit testing. The secondary aims are to assess the ease of donning and doffing, comfort and to assess if factors such as age, gender, ethnicity, BMI and facial dimensions affect the likelihood of passing fit testing.
The data from this study will inform health care facilities on appropriate P2/N95 FFPs to stock for the Australian healthcare population. This will reduce the cost of fit testing and increase the safety of healthcare workers through reduced risk of transmission of airborne diseases such as COVID-19.
Dr Caitlin Low, Box Hill Hospital, Melbourne.
The project was awarded $A15,671 through the ANZCA research grants program for 2022.
At the beginning of the COVID-19 pandemic when healthcare workers were mandated to wear N95 respirators, it was unclear if some N95 respirators were more likely to pass fit testing than others. This was because fit testing (the process of ensuring that the N95 respirator forms an adequate seal) was not yet routinely performed in healthcare workers.
This study was done in that climate to investigate if certain N95 respirators were more likely to pass than others, thus offering greater protection to healthcare workers.
Furthermore, we also wanted to investigate if different N95 respirators had different comfort levels when worn for a prolonged period and whether they had difference in the ease of donning and doffing (putting on and removing the N95 respirator). Comfort and ease of donning/doffing could affect compliance of wearing N95 respirators correctly.
Data from this study could help healthcare facilities to stock the appropriate N95 respirators that takes into account both the pass rate as well as comfort and ease of donning/doffing.
We found that different N95 respirators did indeed have different pass rates and markedly different comfort levels.
There was a small difference in ease of donning and doffing the 4 different N95 respirators. The results from this study further adds to the body of evidence of which N95 respirators should be tested first and highly stocked.
This body of research shows that not all N95 respirators are the same in terms of passing fit testing and that different N95 respirator brands and styles are not interchangeable. Furthermore, we highlighted factors that may affect compliance of wearing N95 respirators, in particular the comfort of wearing the N95 respirator for prolonged periods.
Healthcare workers who wear a N95 respirator that passes fit testing and is compliant with wearing it (due to better comfort) are more likely to reduce the transmission of airborne infectious diseases. The data from this study improves the safety of healthcare workers as well as the general public.
Low CS, Ngui SZ, Casey MJ, Vuong C, Afroz A, Sengupta S, Weinberg L. Pass rates of four P2/N95 respirators or filtering facepiece respirators in Australian healthcare providers: A prospective observational study. Anaesth Intensive Care. 2023 Jul;51(4):268-273. doi: 10.1177/0310057X231154017. Epub 2023 Jun 20. PMID: 37340723