Extended Use or Limited Re-Use
CDC advocated extended use (wearing the same N95 respirators for
repeated close contact encounters with several patients without removing
the respirator between patient encounters), over limited re-using to
conserve supplies.(1, 82, 88) The decision is made by each institution,
taking into account the characteristic of the respiratory pathogen and
local conditions.(88) If no manufacturer guidance is available, limiting
the number of reuse to no more than 5 uses per device to ensure an
adequate safety margin.(82, 88, 94) The filtration efficiency is reduced
to below 95% for filters after 9 and 13 weeks of simulated reuse.(82)
A Dutch study reported that the polypropylene masks (3M type 8822
masks), which do not contain cellulose can be used three times when
sterilised twice with hydrogen peroxide in between use.(95) The mask is
reported to be safe to be treated in hot air at 70◦C for 30 minutes, or
125◦C for 3 minutes but 90◦C heat and 134◦C steam deformed the mask.(95,
96)
Most HCW can tolerate wearing N95 for up to 8 to 12 hours.(1, 82) Ang et
al reported staff using it for the entire shift without removing it to
conserve supply, unless soiled during the H1N1 pandemic.(97) However,
most HCW are unwilling to wear N95 for the entire 8-hour work shift, as
most need to take breaks, thus extended use beyond 4 hours is
unlikely.(1, 78)
N95 respirators should be discarded when grossly contaminated, damaged
or difficult to breathe through.(1) Storage is in a clean, dry location,
or in a single-use breathable container to avoid contamination and
maintain the integrity.(1) In confirmed or highly suspected SARS-nCoV-2
cases, N95 respirators should be single-use only due to the risk of
droplet spray contamination, degradation of filtration efficacy and mask
fit, cross contamination during storage, doffing and donning of the
respirator.(1)