Abstract
IntroductionNosocomial transmission of SARS-CoV-2 has been a major feature of the COVID-19 pandemic. Evidence suggests patients can auto-emit aerosols containing viable viruses, these aerosols could be further propagated when patients undergo certain treatments including continuous positive airway pressure (PAP) therapy. Our aim was to assess i) the degree of viable virus propagated from PAP circuit mask leak, ii) the efficacy of a ventilated plastic canopy to mitigate virus propagation.
MethodsBacteriophage PhiX174 (108 copies·mL−1) was nebulised into a custom PAP circuit. Mask leak was systematically varied at the mask interface. Plates containingEscherichia colihost quantified viable virus (viaplaque forming unit) settling on surfaces around the room. The efficacy of a low-cost ventilated headboard created from a tarpaulin hood and a high efficiency particulate air (HEPA) filter was tested.
ResultsMask leak was associated with virus contamination in a dose-dependent manner (χ2=58.24, df=4, p<0.001). Moderate mask leak (≥21 L·min−1) was associated with virus counts equivalent to using PAP with a vented mask. The highest frequency of viruses was detected on surfaces 1 m away, however, viable viruses were recorded up to 3.86 m from the source. A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates ≥170 m3·人力资源−1eradicated all evidence of virus contamination.
ConclusionMask leak from PAP may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical mask leak levels should be treated as an infectious risk. Low-cost patient hoods with HEPA filtration are an effective countermeasure.
Footnotes
This manuscript has recently been accepted for publication in theEuropean Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of theERJonline. Please open or download the PDF to view this article.
Conflict of interest: Dr. Landry has nothing to disclose.
Conflict of interest: Dr. Barr has nothing to disclose.
Conflict of interest: Dr. MacDonald has nothing to disclose.
Conflict of interest: Dr. Subedi has nothing to disclose.
Conflict of interest: Dr. Mansfield has nothing to disclose.
Conflict of interest: Dr. Hamilton reports non-financial support from Resmed, non-financial support from Philips Respironics, non-financial support from Air Liquide Healthcare, outside the submitted work; .
Conflict of interest: Dr. Edwards reports grants from Monash Partners, grants from Heart Foundation, during the conduct of the study; grants from Apnimed Australia, personal fees from Signifier Medical, outside the submitted work; .
Conflict of interest: Dr. Joosten has nothing to disclose.
- ReceivedSeptember 29, 2020.
- AcceptedNovember 24, 2020.
- Copyright ©ERS 2020