[Maintenance status of N95 respirator masks after use in a health care setting].

With the purpose of assessing the damages to N95 respirator masks over time and to estimate their expiration after use in clinical practice, this study was based on the descriptive analysis of N95 cone-shaped masks collected by nursing assistants after one, five, 15, and 30 consecutive days of use. Personal identification marks were founds in every respirator already on the first day of use. From the fifth day onward, all masks presented some type of dirt while folds were observed in more than 80% of the devices. Internal stains and folds were more frequent among workers of the 12-hour shift in comparison to the 6-hour shift (p < 0.05). The percentage of misplaced respirators was 16.17% by day five and reached 38.93% by day thirty. Though there is no convenience in reusing N95 respirators, their expiration should not exceed 5 days of use.