“Respirators with exhalation valves can be used in a healthcare setting when it is not important to maintain a sterile field (an example of an acceptable practice would be when taking the temperature or blood pressure of a patient). Respirators with exhalation valves should not be used in situations where a sterile field is required (e.g., during an invasive procedure in an operating or procedure room) because the exhalation valve allows unfiltered exhaled air to escape into the sterile field.”
Interesting. It still seems like these respirators would have been earmarked for industrial use, but I didn't realize they could normally be used in healthcare at all.
“Respirators with exhalation valves can be used in a healthcare setting when it is not important to maintain a sterile field (an example of an acceptable practice would be when taking the temperature or blood pressure of a patient). Respirators with exhalation valves should not be used in situations where a sterile field is required (e.g., during an invasive procedure in an operating or procedure room) because the exhalation valve allows unfiltered exhaled air to escape into the sterile field.”
https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part...