Self-Contamination Risk and Failure Modes During High-Level PPE Doffing: A Comparison of Two Powered Air Purifying Respirator (PAPR) Hoods: A Pilot Study.

Background: Personal protective equipment (PPE) doffing protocols can reduce risks of pathogen self-contamination. Powered air purifying respirators (PAPRs) may increase these risks. This study compares viral contamination and errors during simulated doffing of single layer vs double layer hood PAPRs.

Methods: Eight participants performed two simulations (video recorded for failure modes and effects analysis): one single-layer hood (laid over Tyvek suit), and one double-layer hood (top laid over and bottom tucked into suit). Hoods were contaminated with viruses. After doffing, inner gloves, face, hands, and scrubs were sampled.

Results: Virus contaminated least one site in 6/8 single and 5/8 double layer simulations. Virus contaminated inner gloves in single (six participants, median 5.42×10⁴ PFU) and double-layer (two participants, median 7.23×10² PFU) simulations, and hands of two participants in single-layer simulations. Single layer doffing had 13 failure modes; double had 31.

Discussion: Double-layer doffing reduced inner glove contamination. The double-layer protocol may reduce glove-face shield contact but allow more opportunities for error. Double-layer doffing errors may less frequently lead to contamination than single-layer.

Conclusions: Contamination and failure modes may differ between double and single-layer doffing. Although inner glove contamination was reduced, double-layer doffing may need redesign to reduce failure modes and contamination.