Retrospective evaluation of factors affecting successful fit testing of respiratory protective equipment during the early phase of COVID-19

OBJECTIVES

Respiratory protective equipment is critical to protect healthcare workers from COVID-19 infection, which includes filtering facepiece respirators (FFP3). There are reports of fitting issues within healthcare workers, although the factors affecting fitting outcomes are largely unknown. This study aimed to evaluate factors affecting respirator fitting outcomes.

DESIGN

This is a retrospective evaluation study. We conducted a secondary analysis of a national database of fit testing outcomes in England between July and August 2020.

SETTINGS

The study involves National Health Service (NHS) hospitals in England.

PARTICIPANTS

A total of 9592 observations regarding fit test outcomes from 5604 healthcare workers were included in the analysis.

INTERVENTION

Fit testing of FFP3 on a cohort of healthcare workers in England, working in the NHS.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measure was the fit testing result, that is, pass or fail with a specific respirator. Key demographics, including age, gender, ethnicity and face measurements of 5604 healthcare workers, were used to compare fitting outcomes.

RESULTS

A total of 9592 observations from 5604 healthcare workers were included in the analysis. A mixed-effects logistic regression model was used to determine the factors which affected fit testing outcome. Results showed that males experienced a significantly (p<0.05) higher fit test success than females (OR 1.51; 95% CI 1.27 to 1.81). Those with non-white ethnicities demonstrated significantly lower odds of successful respirator fitting; black (OR 0.65; 95% CI 0.51 to 0.83), Asian (OR 0.62; 95% CI 0.52 to 0.74) and mixed (OR 0.60; 95% CI 0.45 to 0.79.

CONCLUSION

During the early phase of COVID-19, females and non-white ethnicities were less likely to have a successful respirator fitting. Further research is needed to design new respirators which provide equal opportunity for comfortable, effective fitting of these devices.

The influence of gender and ethnicity on facemasks and respiratory protective equipment fit: a systematic review and meta-analysis

INTRODUCTION

Black, Asian and minority ethnic (BAME) people are disproportionately affected by COVID-19. Respiratory protective equipment (RPE) has conventionally been developed for a predominantly white male population that does not represent the healthcare workforce. The literature was reviewed to determine the protection offered to female and BAME users.

METHODS

Five databases were searched. Eligible studies related to respirator fit in the context of anthropometrics, gender and ethnicity. Meta-analysis was performed for gender-based anthropometric differences. A priori protocol registration was not performed.

RESULTS

32 studies were included and anthropometric data was extracted from 15 studies. Meta-analysis revealed 14 anthropometric measurements were significantly smaller for females. Mean differences ranged from 0.37 mm to 22.05 mm. Gender-based anthropometric differences did not always translate to lower fit factor scores, with 12 studies reporting worse performance and fit for females and 10 reporting no gender effect. No studies provided disaggregate anthropometric data by ethnic group. Pass rates (PR) were low or moderate in 12 BAME or mixed-ethnicity cohorts. 14 studies reported associations between facial dimensions (FD) and respirator fit. Three comparative studies showed lower PR among selective BAME people. 18 studies reported RPE performance differed with model and design. Most studies did not prespecify inclusion/exclusion criteria. Small sample size and lack of justification or power calculations was a concern. Significant heterogeneity in study designs limited comparisons, particularly relating to respirator selection or availability and defining study outcomes relating to RPE performance.

CONCLUSION

The literature reports on largely Caucasian or single ethnic populations, and BAME people remain under-represented, limiting comparisons between ethnic groups. Facial anthropometrics vary between gender and likely between ethnicity, which may contribute to lower PR among females and ethnic minorities, particularly Asians. There is a need for studies including a broader spectrum of ethnicities and for consideration of female and BAME users during RPE development.

Quantitative fit testing of filtering face-piece respirators during the COVID-19 pandemic reveals anthropometric deficits in most respirators available in Iran

PURPOSE

Frontline health care workers (HCWs) must wear a standard N95 or FFP2 respirator during worldwide pandemics of respiratory diseases including COVID-19 to protect against airborne infectious pathogens when performing care activities. This study aimed to quantitatively investigate the fit of most of the common FFRs used during the COVID-19 pandemic in Iran.

METHODS

A total of 37 volunteers were fit tested in 20 selected FFRs in a randomized order. The selected FFRs were underwent quantitative fit testing by PortaCount® model 8038. To determine the effects of face sizes on respirator fit, the participants' facial dimensions were measured using a digital caliper.

RESULTS

The rate of passing fit tests for the studied FFRs were surprisingly low with 11 out of 20 FFRs having less than 10% passing fit tests and the best performers having only 43% and 27% passing fit tests (brands 2 and 20, respectively). Cup-shaped respirators provided significantly greater fit than the vertical flat-fold ones (p < 0.001). A significantly different FFs were found among the respirator brands (F = 13.60, p < 0.001).

CONCLUSION

Overall, unacceptably low fit factors were obtained from the studied FFRs. The main reasons for this are suspected to single size and style for each studied FFR. It confirms the importance and requirement of the proper respirator selection in that way fitted optimally into facial dimensions, appropriate usage, and properly performing the fit testing procedure. A unique fit test panel should be developed to guide respirator wearers in selecting the appropriate FFR for their specific face sizes.

Qualitative fitting characteristics of filtering face-piece respirators on Iranian people

To evaluate the qualitative fitting characteristics of FFRs on Iranian people. 62 participants were fit tested qualitatively by four brands of FFRs, including three imported (A, B, and C) and one domestic (D). The respirators were assigned to the participants randomly based on the Latin Square design (LSD) using the Moldex® Bitrex® Fit Test Kit. R 3.2.5.0 software was used to analyze the data. Among the respirators, A and C respirators had the lowest and highest fit test passing rates with 1.60% and 43.50%, respectively. The majority of the participants had medium face sizes (45.20%) and small and long/narrow shapes (32.20% and 32.30%). There was a significant difference between the passing rate of domestic (D) and imported (C) respirators (p value<0.001). Factors including respirator brand, style, and gender had significant effects on respirator fit (p value<0.01). There was a low fit test passing rate of the studied respirators among participants. Furthermore, 19.40% of the participants fell out of the NIOSH fit test panel. Therefore, it is required to develop a unique bivariate fit test panel and design the respirators based on the Iranian facial dimensions. Meantime, manufacturers need to provide various sizes and styles of the respirators to provide adequate respiratory protection for the users.