title: Physiological impact of the N95 filtering facepiece respirator on healthcare workers.
abstract: OBJECTIVE
  To assess the physiological impact of the N95 filtering facepiece respirator (FFR) on healthcare workers.
  
  
  METHODS
  Ten healthcare workers each conducted multiple 1-hour treadmill walking sessions, at 1.7 miles/h, and at 2.5 miles/h, while wearing FFR with exhalation valve, FFR without exhalation valve, and without FFR (control session). We monitored heart rate, respiratory rate, tidal volume, minute volume, blood oxygen saturation, and transcutaneously measured P(CO2). We also measured user comfort and exertion, FFR moisture retention, and the carbon dioxide and oxygen concentrations in the FFR's dead space.
  
  
  RESULTS
  There were no significant differences between FFR and control in the physiological variables, exertion scores, or comfort scores. There was no significant difference in moisture retention between FFR with and without exhalation valve. Two subjects had peak P(CO2) > or = 50 mm Hg. The FFR with exhalation valve offered no benefit in physiological burden over the FFR without valve. The FFR dead-space oxygen and carbon dioxide levels did not meet the Occupational Safety and Health Administration's ambient workplace standards.
  
  
  CONCLUSIONS
  In healthy healthcare workers, FFR did not impose any important physiological burden during 1 hour of use, at realistic clinical work rates, but the FFR dead-space carbon dioxide and oxygen levels were significantly above and below, respectively, the ambient workplace standards, and elevated P(CO2) is a possibility. Exhalation valve did not significantly ameliorate the FFR's P(CO2) impact.
authors.affiliation: Technology Research Branch, National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA. dtn0@cdc.gov
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Roberge
authors.forename: Aitor
authors.initials: A
authors.lastname: Coca
authors.forename: W Jon
authors.initials: WJ
authors.lastname: Williams
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Powell
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Palmiero
mesh_terms: D000328:Adult; D004867:Equipment Design; D004869:Equipment Safety; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006282:Health Personnel; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008397:Masks / Q000592:standards*; D008875:Middle Aged; D016273:Occupational Exposure / Q000517:prevention & control*; D010101:Oxygen Consumption / Q000502:physiology; D012016:Reference Values; D012134:Respiratory Protective Devices / Q000592:standards*; D013990:Tidal Volume / Q000502:physiology; D014939:Work of Breathing / Q000502:physiology*; D017132:Workplace / Q000592:standards; D055815:Young Adult