Assessing real-time performances of N95 respirators for health care workers by simulated workplace protection factors

Abstract

To assess performances of N95 respirators for Health Care Workers (HCWs) in a simulated health-care setting, we measured the Simulated Workplace Protection Factors (SWPFs) in real-time from the volunteers. A total of 49 study subjects, wearing 3 M respirator Model N95 1860 and 1860S, were fit tested using the OSHA Exercise Regimen. The test subjects were asked to perform simulated scenarios, including patient assessments, suction, and intravenous injection (IV) treatment. Two TSI PortaCount instruments continuously measured concentrations in the respirator and the room concentration. For Quantitative Fit Testing (QNFT), 36 out of 49 (73.5%) passed the fit factor (FF) criteria set at 100 and 13 (26.5%) failed. The results of QNFT were found to have a low correlation with SWPF, with R2=0.32. The geometric means (GM) and geometric standard deviations (GSD) of SWPF were 68.8 (1.1) for those subjects who passed and 39.6 (1.3) for those who failed. Real-time assessments of SWPF showed that lower SWPFs were; moving head up and down, and bending at the waist. This study identifies the needs for providing different sizes of respirators for HCWs and the importance of performing fit tests for HCWs regularly. And particular movements were identified as attributing factors affecting more on SWPFs.

Fit Characteristics of N95 Filtering Facepiece Respirators and the Accuracy of the User Seal Check among Koreans

“…A more recent Korean study found that the QNFT pass rate of a single model (3M 1860/1860S) was 73.5%. 7 The pass rate of the same model in another study from China was slightly lower (57.4%-61.3%). 8 Despite a moderate difference in pass rates, our results are in line with those of previous Asian studies reporting low QNFT pass rates.…”

Performance of two respiratory protective devices used by home-attending health care workers (a pilot study)

“…(6) Head or body movements, such as bending at the waist and moving the head up and down, have been identified as factors affecting the simulated WPF. (7) In general, head and body movement may affect the RPD’s fit, and thus, the WPF given that the faceseal leakage often represents the main penetration pathway for particles to enter into an RPD. (7,9) The between-activity variation of the WPF TWA(C) value was considerable.…”

“…Also before the workplace evaluation, the participating workers were fit tested with the N95 FFR selected for the study (SM is not subjected to fit testing). Consistent with the US OSHA protocol 29 CFR1910.134 (7) , a PortaCount (Model 8020, TSI, Inc., Shoreview, MN) was used for the fit testing. A particle generator (Model 8026, TSI Inc.) was used to provide an ambient aerosol concentration sufficient to perform the fit testing (at least 1000 particles/cm 3 ).…”

“…Studies examining the protection offered by N95 FFRs and SMs have been mostly conducted in laboratory settings (4) , with few attempting to evaluate their efficiency in simulated health-care settings. (5–7) Existing guidelines and recommendations for protecting health-care workers do not extend to those attending patients in their homes.…”

Simulated workplace protection factors for respirators with N95 or higher filters for health care providers in an emergency medical centre: A randomized crossover study

“…Primary outcomes were the fit factors of the three respirators. Secondary outcomes were adequate protection, which was defined as the percentage of fit factor greater than or equal to 100, as this suggests that the respirator provided proper protection, [16][17][18] the overall fit factor and the preference of respirator. The overall fit factor was calculated from the individual fit factors determined for each test exercise performed by each participant where FFn is the fit factor of n movement of one participant.…”