Assessment of aloe vera for qualitative fit testing of particulate respirators: a logistic regression approach

A Medical Nebulizer as a Substitute for the OSHA-Approved Nebulizer for Qualitative Fit Testing of Respirators During the Respiratory Infectious Pandemics: An Experimental Feasibility Study

OBJECTIVE

The qualitative fit testing procedure would be challenging due to severe shortages, high cost, and unavailability of commercial fit test kits in the marketplaces during pandemics of respiratory infectious diseases. Assessment of alternatives for commercial fit test kits to be prepared for emergencies is critically required. This study aimed to investigate the feasibility of an alternative of the Accumed NF60 nebulizer for the Occupational Safety and Health Administration (OSHA)-approved Allegro nebulizer.

METHODS

Thirty-two participants were randomly allocated to 6 filtering facepiece respirators (FFRs). They were qualitatively fit tested by both manual Allegro and automated Accumed NF60 nebulizers.

RESULTS

There was no statistically significant difference between the Allegro and Accumed NF60 nebulizers by passing rates. The odds for passing fit testing using the Accumed NF60 nebulizer was similar to that of the Allegro one (odds ratio=1.0, 95% confidence interval [0.58-1.74]).

CONCLUSIONS

The Accumed NF60 nebulizer could be used as a cost-benefit substitute for the standard fit test nebulizers in the pandemic situation where there is a shortage and difficulty of access. It is more convenient, decreases the time investment, and reduces the contact stress in the operators' hands as it does not require squeezing the nebulizer bulb frequently. The test solutions' preparation and fit testing procedures on many personnel are more straightforward, efficient, and hygienic than the Allegro one.

Efficacy of facemasks in mitigating respiratory exposure to submicron aerosols

We designed a novel experimental set-up to pseudo-simultaneously measure size-segregated filtration efficiency (η_F), breathing resistance (η_P) and potential usage time (t_B) for 11 types of face protective equipment (FPE; four respirators; three medical; and four handmade) in the submicron range. As expected, the highest η_F was exhibited by respirators (97 ± 3%), followed by medical (81 ± 7%) and handmade (47 ± 13%). Similarly, the breathing resistance was highest for respirators, followed by medical and handmade FPE. Combined analysis of efficiency and breathing resistance highlighted trade-offs, i.e. respirators showing the best overall performance across these two indicators, followed by medical and handmade FPE. This hierarchy was also confirmed by quality factor, which is a performance indicator of filters. Detailed assessment of size-segregated aerosols, combined with the scanning electron microscope imaging, revealed material characteristics such as pore density, fiber thickness, filter material and number of layers influence their performance. η_F and η_P showed an inverse exponential decay with time. Using their cross-over point, in combination with acceptable breathability, allowed to estimate t_B as 3.2-9.5 h (respirators), 2.6-7.3 h (medical masks) and 4.0-8.8 h (handmade). While relatively longer t_B of handmade FPE indicate breathing comfort, they are far less efficient in filtering virus-laden submicron aerosols compared with respirators.

Qualitative fitting characteristics of elastomeric half face-piece respirators using Isoamyl acetate agent

To examine the fit testing of elastomeric half face-piece respirators (EHRs), a total of 41 candidates were randomly assigned into seven EHRs equipped with organic vapor (OV) cartridges which were commonly used in the Iranian industrial workplaces. The qualitative fitting into the facial dimensions was assessed using the Allegro Isoamyl Acetate fit test kit. While the studied EHRs showed very low passing fit testing rates, the 3M, AoSafety (Medium), and AoSafety (Large) had the highest passing rates with 22.0%, 14.60%, and 9.76%, respectively. The AoSafety (All sizes) delivered a higher passing fit test rate than the 3M brand (29.30 vs. 22.0%). The one size fits all respirators including the DUO and Climax showed lower proportions of passing fit tests compared with AoSafety three-size system brands (2.40% and 4.90% vs. 29.30%). Low fit test passing rates were determined among different respirators. The respirators with various sizes and styles had more opportunities for different wearers to pass the fit test than single size models. The initial and annual fit testing requirements shall be developed by local government. Also, the manufacturers are required to pay attention to respirator features and subject characteristics during the production to obtain satisfactory protection for the end-users.

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.

Performing Qualitative Mask Fit Testing Without a Commercial Kit: Fit Testing Which Can Be Performed at Home and at Work

OBJECTIVE

Qualitative fit testing is a popular method of ensuring the fit of sealing face masks such as N95 and FFP3 masks. Increased demand due to the coronavirus disease 2019 (COVID-19) pandemic has led to shortages in testing equipment and has forced many institutions to abandon fit testing. Three key materials are required for qualitative fit testing: the test solution, nebulizer, and testing hood. Accessible alternatives to the testing solution have been studied. This exploratory qualitative study evaluates alternatives to the nebulizer and hoods for performing qualitative fit testing.

METHODS

Four devices were trialed to replace the test kit nebulizer. Two enclosures were tested for their ability to replace the test hood. Three researchers evaluated promising replacements under multiple mask fit conditions to assess functionality and accuracy.

RESULTS

The aroma diffuser and smaller enclosures allowed participants to perform qualitative fit tests quickly and with high accuracy.

CONCLUSIONS

Aroma diffusers show significant promise in their ability to allow individuals to quickly, easily, and inexpensively perform qualitative fit testing. Our findings indicate that aroma diffusers and homemade testing hoods may allow for qualitative fit testing when conventional apparatus is unavailable. Additional research is needed to evaluate the safety and reliability of these devices.