A crossover study assessing the protective efficacy of improvised snorkel-based improvised respirators

Abstract

IntroductionThis study was designed to determine whether improvised respirators based on modified full-face snorkel masks are able to pass a standard qualitative fit test MethodsThis is a prospective crossover study conducted in 16 staff Fit-tests were conducted on masks mated to (1) an anaesthetic breathing circuit heat and moisture exchange filter and (2) a CE-marked P3 grade filter P3 filters were mounted using both epoxy-coated and uncoated adaptors ResultsNone of the tests using anaesthetic filters passed Only one overall pass was observed using the P3-rated filter mated to the snorkel mask ConclusionsThese data suggest that improvised PPE designs cannot provide reliable protection against aerosols Failures are likely due to poor fit, but the suitability of 3D printed materials is also uncertain as fused-filament manufacturing yields parts that are not reliably gas-tight Improvised PPE cannot be recommended as a substitute for purpose designed systems