Surgical helmets can be converted into efficient disinfectable powered air-purifying respirators

Am J Infect Control. 2022 Jun;50(6):624-630. doi: 10.1016/j.ajic.2021.12.002. Epub 2021 Dec 25.


Background: Filtering facepiece respirators often fail to provide sufficient protection due to a poor fit. Powered air-purifying respirators (PAPRs) are not designed for healthcare personnel, and are challenging to disinfect. Surgical helmets (SH) are available in many United States hospitals but do not provide respiratory protection. Several modifications to SH have been suggested, but none are sufficiently compliant with safety and efficiency standards. The purpose of this investigation was the development of a filter adaptor, which converts SHs into efficient, safe, and disinfectable PAPRs.

Methods: Four critical features were investigated close to regulatory requirements: total inward leakage of particles, CO2 concentrations, intra-helmet differential pressure, and automated disinfection.

Results: The average total inward leakage in the 2 independent tests were 0.005% and 0.01%. CO2 concentrations were lower than in the original SH. The modification generates a positive differential pressure. The filter's performance was not compromised after 50 cycles in a sterilization machine.

Discussion: The modified SH provides several hundred times better protection than FFP-3 masks.

Conclusions: Surgical helmets can be modified into safe, efficient, and disinfectable PAPRs, suitable for HCP and the operating room in particular. They can play a role in the preparedness for upcoming events requiring efficient respiratory protection.

Keywords: 3D printing; COVID-19; Emergency Prepardeness; Orthopedic Surgery; Respiratory protection; Total Inward Leakage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Dioxide
  • Head Protective Devices
  • Humans
  • Masks
  • Occupational Exposure* / prevention & control
  • Respiratory Protective Devices*
  • United States


  • Carbon Dioxide