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Feasibility study: Proposed alternative to N95 respirator during the personal protective equipment shortage from COVID-19 pandemic

Ahel El Haj Chehade, MD, Jesintha Stephenson, MD, Evan Floyd, PhD, Jean Keddissi, MD, FCCP, Tony Abdo, MD, Sharanjeet Thind, MD, Jamie Stringfellow, RRT, Houssein Youness, MD, FCCP


Introduction: Having an adequate supply of personal protective equipment during the COVID-19 pandemic has been a constant challenge for hospitals across the United States. In the event of shortages, our assembled mask might offer noninferior protection compared to an N95 respirator.

Objective: To study the ability of an assembled mask to pass a quantitative fit testing.

Methods: We conducted a feasibility study at the Oklahoma City Veteran Affairs Health Care System. Volunteers were fitted with an assembled mask made of either a Hans Rudolph half-face mask or a Respironics Performax full-face mask, attached to an Iso-Gard HEPA light Filter 28022 through a Performax SE elbow hinge. Quantitative fit testing was conducted using the Occupation Safety and Health Administration fit testing protocol. The primary outcome was the percentage of participants who pass the quantitative fit test. Secondary outcomes included the overall fit factor (FF), average FF for different exercises, changes in pulse oximetry and endtidal CO2 at 0 and 15 minutes, willingness to use the mask, and visibility assessment.

Results: Twenty participants completed the study, and all (100 percent) passed the quantitative fit testing. The overall FF had a geometric mean of 2,317 (range: 208-16,613) and a geometric standard deviation of 3.8. The lowest FF was recorded while the subjects were talking. Between time 0 and 15 minutes, there was no clinically significant change in pulse oximetry and end-tidal CO2 levels. Most participants reported “very good” visibility and were “highly likely” to use the Hans Rudolph half-face mask in the case of shortage.

Conclusion: Our assembled respirator offers noninferior protection to N95 respirators in the setting of hypothetical protective equipment shortage.


COVID-19, pandemic, personal protective equipment, respirator

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