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)