[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.