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Subject validation of reusable N95 stop-gap filtering facepiece respirators in COVID-19 pandemic.
Ng, William C K; Mbadjeu Hondjeu, Arnaud Romeo; Syrett, Andrew; Caragata, Rebecca; Rozenberg, Dmitry; Xiao, Zixuan; Anwari, Vahid; Trac, Jessica; Mashari, Azad.
  • Ng WCK; Department of Anesthesiology and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
  • Mbadjeu Hondjeu AR; Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, Ontario, Canada.
  • Syrett A; Department of Anesthesiology and Pain Management, Cardiac Division, Hospital for Sick Children, Toronto, Ontario, Canada.
  • Caragata R; Department of Anesthesiology and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
  • Rozenberg D; Department of Anesthesiology and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
  • Xiao Z; Department of Anesthesiology and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
  • Anwari V; Division of Respirology and Lung Transplantation, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.
  • Trac J; Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
  • Mashari A; Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada.
PLoS One ; 15(11): e0242304, 2020.
Article in English | MEDLINE | ID: covidwho-926880
ABSTRACT

INTRODUCTION:

The COVID-19 pandemic has unveiled widespread shortages of personal protective equipment including N95 respirators. Several centers are developing reusable stop-gap respirators as alternatives to disposable N95 respirators during public health emergencies, using techniques such as 3D-printing, silicone moulding and plastic extrusion. Effective sealing of the mask, combined with respiratory filters should achieve 95% or greater filtration of particles less than 1um. Quantitative fit-testing (QNFT) data from these stop-gap devices has not been published to date. Our team developed one such device, the "SSM", and evaluated it using QNFT.

METHODS:

Device prototypes were iteratively evaluated for comfort, breathability and communication, by team members wearing them for 15-30min. The fit and seal were assessed by positive and negative pressure user seal checks. The final design was then formally tested by QNFT, according to CSA standard Z94.4-18 in 40 volunteer healthcare providers. An overall fit-factor >100 is the passing threshold. Volunteers were also tested by QNFT on disposable N95 masks which had passed qualitative fit testing (QLFT) by institutional Occupational Health and Safety Department.

RESULTS:

The SSM scored 3.5/5 and 4/5 for comfort and breathability. The median overall harmonic mean fit-factors of disposable N95 and SSM were 137.9 and 6316.7 respectively. SSM scored significantly higher than disposable respirators in fit-test runs and overall fit-factors (p <0.0001). Overall passing rates in disposable and SSM respirators on QNFT were 65% and 100%. During dynamic runs, passing rates in disposable and SSM respirators were 68.1% and 99.4%; harmonic means were 73.7 and 1643.

CONCLUSIONS:

We present the design and validation of a reusable N95 stop-gap filtering facepiece respirator that can match existent commercial respirators. This sets a precedence for adoption of novel stop-gap N95 respirators in emergency situations.
Subject(s)

Full text: Available Collection: International databases Database: MEDLINE Main subject: Pneumonia, Viral / Respiratory Protective Devices / Coronavirus Infections / Equipment Design / Pandemics Type of study: Experimental Studies / Prognostic study / Qualitative research Limits: Adult / Female / Humans / Male / Middle aged Language: English Journal: PLoS One Journal subject: Science / Medicine Year: 2020 Document Type: Article Affiliation country: Journal.pone.0242304

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Full text: Available Collection: International databases Database: MEDLINE Main subject: Pneumonia, Viral / Respiratory Protective Devices / Coronavirus Infections / Equipment Design / Pandemics Type of study: Experimental Studies / Prognostic study / Qualitative research Limits: Adult / Female / Humans / Male / Middle aged Language: English Journal: PLoS One Journal subject: Science / Medicine Year: 2020 Document Type: Article Affiliation country: Journal.pone.0242304