Sterile field contamination from powered air-purifying respirators (PAPRs) versus contamination from surgical masks

Am J Infect Control. 2020 Feb;48(2):153-156. doi: 10.1016/j.ajic.2019.08.009. Epub 2019 Sep 10.

Abstract

Background: Currently, powered air-purifying respirators (PAPRs) are not recommended for usage in close proximity to sterile fields owing to concerns that exhaled, unfiltered air potentially may cause contamination; however, this has not been confirmed by experimental study.

Methods: After establishing background levels of airborne contamination, our team placed settling plates in a sterile field and collected contamination from participants who were performing particulate-generating actions. Participants performed the actions while wearing various forms of respiratory protection, including: (1) a full facepiece PAPR, (2) a full facepiece PAPR with a shoulder-length hood, (3) a surgical mask, and (4) no facial covering (as a positive control to determine contamination-reduction effectiveness). Specimens were collected at the end of a 10-minute sampling time frame. After incubation at 36.5˚C for 72 hours, we tabulated colony forming units as a marker of contamination.

Results: Surgical masks and the 2 PAPR configurations all drastically reduced aerosolized droplet contamination. Surgical masks reduced contamination by 98.48%, and both PAPRs reduced contamination by 100% (compared with the usage of no facial covering). There was no statistical difference between their effectiveness (surgical mask vs both PAPRs, P value = .588 and no hood PAPR vs hood PAPR, P value >.999).

Discussion/conclusions: Based on these findings, the tested PAPR configurations are effective at reducing aerosolized droplet contamination into a sterile field, and further testing is warranted to assess other PAPR configurations as well as PAPR suitability in an operating room.

Keywords: Aerosol; Nosocomial; PPE; Surgery.

MeSH terms

  • Aerosols
  • Air Microbiology / standards*
  • Humans
  • Infection Control / instrumentation*
  • Infection Control / methods
  • Masks*
  • Occupational Exposure / prevention & control
  • Operating Rooms
  • Respiratory Protective Devices*

Substances

  • Aerosols