Reprocessing filtering facepiece respirators in primary care using medical autoclave: prospective, bench-to-bedside, single-centre study

Abstract

ObjectiveThere are widespread shortages of personal protective equipment as a result of the COVID-19 pandemic. Reprocessing filtering facepiece particle (FFP)-type respirators may provide an alternative solution in keeping healthcare professionals safe.DesignProspective, bench-to-bedside.SettingA primary care-based study using FFP-2 respirators without exhalation valve (3M Aura 1862+ (20 samples), Maco Pharma ZZM002 (14 samples)), FFP-2 respirators with valve (3M Aura 9322+ (six samples) and San Huei 2920V (16 samples)) and valved FFP type 3 respirators (Safe Worker 1016 (10 samples)).InterventionsAll masks were reprocessed using a medical autoclave (17 min at 121°C with 34 min total cycle time) and subsequently tested up to three times whether these respirators retained their integrity (seal check and pressure drop) and ability to filter small particles (0.3–5.0 µm) in the laboratory using a particle penetration test.ResultsWe tested 33 respirators and 66 samples for filter capacity. All FFP-2 respirators retained their shape, whereas half of the decontaminated FFP-3 respirators showed deformities and failed the seal check. The filtering capacity of the 3M Aura 1862 was best retained after one, two and three decontamination cycles (0.3 µm: 99.3%±0.3% (new) vs 97.0±1.3, 94.2±1.3% or 94.4±1.6; p<0.001). Of the other FFP-2 respirators, the San Huei 2920 V had 95.5%±0.7% at baseline vs 92.3%±1.7% vs 90.0±0.7 after one-time and two-time decontaminations, respectively (p<0.001). The tested FFP-3 respirator (Safe Worker 1016) had a filter capacity of 96.5%±0.7% at baseline and 60.3%±5.7% after one-time decontamination (p<0.001). Breathing and pressure resistance tests indicated no relevant pressure changes between respirators that were used once, twice or thrice.ConclusionThis small single-centre study shows that selected FFP-2 respirators may be reprocessed for use in primary care, as the tested masks retain their shape, ability to retain particles and breathing comfort after decontamination using a medical autoclave.

Ultraviolet-C as a Viable Reprocessing Method for Disposable Masks and Filtering Facepiece Respirators

“…However, when pandemics, such as the one of Coronavirus 2019 (COVID-19), happen, conditions for a perfect storm happen, creating a combination of two factors: (1) a higher demand-side pressure for those pieces of equipment on a global scale [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ], added to (2) failure on the supply-side to meet these needs, as most SUPPE supply chains were in China, and they were unable to export their products [ 11 ]. When this perfect storm occurs, reprocessing SUPPE gains visibility as there is no universal treatment [ 10 , 12 , 13 ]. Despite the fact that there are now multiple vaccines, SUPPE demand will continue to suffer pressures until countries reach herd immunization, especially if countries start banning woven masks, as in Germany or France, due to virus mutations.…”

“…Even though such changes in perspective happened, there is still no universal option for reprocessing SUPPE. This lack of universal choice happens because each option may affect SUPPE’s efficiency and integrity, diminishing its barrier capability [ 1 , 4 , 7 , 8 , 10 , 14 ]. Given that there is no universal choice, reprocessing SUPPE must consider their materials, topologies, the resources at hand, and the markets’ acceptance [ 3 , 12 , 25 ].…”

Sterilization of disposable face masks with respect to COVID-19 shortages; a nationwide field study including 19 sterilisation departments

“…A sterilization facility of a Dutch CSSD (ISO 7 validated, Van Straten Medical, De Meern, the Netherlands, operated by CSA services) was rebuilt for the purpose of reprocessing used (potential Covid-19 contaminated) FFP2 face masks. New testing methods were built to test the filter material quality after sterilization [4,9,16]. The testing facility was open for any hospital, reseller, manufacturer to check the quality of sterilized or new face masks.…”

“…Since hospitals needed to know if 121 °C sterilisation method was safe and effective, pilot studies were conducted that included ATCC 12228 bacteria testing. After demonstrating that sterilisation up to 5 times is possible for high quality face masks, we made the protocols and results available to hospitals via the repository of the Delft University of Technology [9,16]. However, the accuracy of this new method was not explored.…”

Decontamination methods for respiratory protection mask model N95: a rapid review

“…As it is an equipment present in all hospital environments, the autoclave was evaluated by 7 studies with the perspective of being an accessible method. 31,32,44,45,60,69,72 Autoclave disinfection was effective in eliminating Bacillus subtilis spores, 45 however, had little altered the structural integrity of the masks. 44…”