Half-Mask vs N95 Filtering Facepiece Respirators During Simulated Resuscitation (2024)

Research Letter

Occupational Health

Andrew J.Barros,MD1; Costi D.Sifri,MD2,3; Taison D.Bell,MD1,2; et al Joshua C.Eby,MD2,4; Kyle B.Enfield,MD1

Author Affiliations Article Information

Respirators provide protection from airborne particles, and the N95 filtering facepiece respirator (FFR) is the most commonly used type in health care. Recent FFR shortages have led to increased interest in reusable elastomeric half-mask respirators (EHMRs),^1,2 which have a flexible interface and larger straps than FFRs. Data from simulation and industrial settings suggests that EMHRs may provide higher respiratory protection than FFRs.³ Case reports in previous severe acute respiratory syndrome coronavirus pandemics have suggested transmission during cardiopulmonary resuscitation (CPR) despite FFR use,⁴ and simulation studies have demonstrated an unacceptable leak during CPR in up to 40% FFR users.⁵ Owing to shortages of FFR models, individuals who could not be fit in an available FFR model were fit for an EMHR. We assessed whether EHMRs provide improved fit during simulated CPR compared with FFRs.

We conducted a nonrandomized controlled trial of clinicians and health care workers (physicians, advanced practice clinicians, nurses, and nursing assistants) working at a single institution from October 26, 2020, to November 4, 2020 (NCT04591756). The University of Virginia Institutional Review Board for Health Sciences Research approved this study, and all participants provided verbal informed consent. The Transparent Reporting of Evaluations With Nonrandomized Designs (TREND) reporting guideline was used for this study.⁶

Participants were recruited from wards that cared for patients with coronavirus disease 2019 (COVID-19). All participants had previously completed a National Institute for Occupational Safety and Health–approved fit test, had been assigned a model of EHMR or FFR for use, and had used recently their assigned model of respirator. At our institution, disposable FFRs are used for a single patient care session, captured for inspection and reprocessing, returned for reuse up to 6 times, and then discarded.

Each participant preformed chest compressions on a mannequin while denatonium benzoate was aerosolized into a fit-testing hood (trial protocol in Supplement 1) and while wearing their assigned model of EHMR or FFR. Testing was stopped after 2 minutes or when the participant reported detection of the agent. Our primary end point was detection of the test agent indicating poor respiratory fit. The secondary end point was the time to detection of the agent. Information on employment role, years of respirator use, and respirator model was collected.

We hypothesized that FFRs would have a 40% failure rate and that EMHR would provide a 50% relative risk reduction. We calculated that 81 participants per group would give 80% power with a 5% type I error rate. Interim analyses of the primary end point were preplanned with 50, 100, and 150 participants using the Haybittle-Peto boundary (ie, 2-sided P < .001 was considered significant for early stopping and 2-sided P < .05 for final analysis). The χ² test was used for all count data. Analyses were performed using R, version 4.0.2 (R Foundation for Statistical Computing).

The final analysis included 100 participants (Table). The study was stopped after the second interim analysis crossed the prespecified threshold. Participants reported detection of the agent in 0 of 36 tests in the EMHR group and 18 of 64 tests (28.1%) in the FFR group (risk difference, −28.1%; 95% CI −39.1% to −17.1%). Participants reported detection of the agent at a median of 69 seconds (interquartile range, 42-107 seconds) (Figure). An association between the primary end point and participant employment role, years of respirator use, or FFR model was not found.

Our results suggest that FFR fit during CPR is poor and that EMHRs provide superior fit, confirming previous research.⁵ We chose to evaluate fit during CPR because it is highly aerosolizing, physically strenuous, and has been associated with occupational transmission. Strengths of our study include our real-world design and prospective data collection. Limitations include the lack of blinding or randomization and the use of participant-reported detection. The data suggest that the EMHR is more effective at preventing aerosol inhalation during strenuous clinical work and should be considered for preventing COVID-19 transmission.

Accepted for Publication: January 21, 2021.

Published: March 16, 2021. doi:10.1001/jamanetworkopen.2021.1564

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Barros AJ et al. JAMA Network Open.

Corresponding Author: Andrew J. Barros, MD, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Virginia School of Medicine, PO Box 800546, Charlottesville, VA 22908-0546 (abarros@virginia.edu).

Author Contributions: Drs Barros and Enfield had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Barros, Sifri, Bell, Enfield.

Drafting of the manuscript: Barros, Enfield.

Critical revision of the manuscript for important intellectual content: Sifri, Bell, Eby, Enfield.

Statistical analysis: Barros.

Administrative, technical, or material support: Barros, Eby, Enfield.

Supervision: Barros, Sifri, Bell, Enfield.

Conflict of Interest Disclosures: Dr Sifri reported receiving grants from University of Virginia Global Infectious Disease Institute outside the submitted work. No other disclosures were reported.

Data Sharing Statement: See Supplement 2.

Additional Contributions: We thank the staff in the UVA Health special pathogen units for their participation in the study. Amy Warren, MS (Clinical Trials Office, School of Medicine, University of Virginia), assisted with preparing the trial protocol for institutional review board submission and was not compensated for this work.