Study shows knowledge gaps in N-95 respirator use

Apr 9, 2007 (CIDRAP News) – N-95 respirators are regarded as a key tool for protecting people from airborne influenza viruses in the event of a pandemic, but a recent study suggests that without special instruction, most people are likely to wear the devices incorrectly, limiting their effectiveness.

To gauge the public's current knowledge of how to use N-95 respirators, the researchers randomly questioned 538 people in New Orleans about their experience with the devices during hurricane clean-up and asked them to demonstrate putting on a respirator. Conducted by occupational safety experts from the Centers for Disease Control and prevention, the study appears in an early online edition of Emerging Infectious Diseases.

N-95 respirators, designed to stop at least 95% of small airborne particles, are used, among other purposes, to prevent the transmission of communicable diseases in healthcare settings and to reduce exposure to mold during flood cleanups. Donning a respirator improperly is likely to promote the leakage of unfiltered through gaps between the respirator and the skin, the authors note.

Among those interviewed for the study, 42% (233) had used a certified respirator for mold clean-up after Hurricane Katrina and 35% (192) had used N-95 models.

The respirators used in the study included written and pictorial instructions, but the volunteers were not given any additional instructions before putting them on, the report says.

In watching participants don the respirators, investigators found that only 24% (129 of 538) wore the devices properly. The most common errors were not tightening the nose clip (71%), incorrectly placing the straps (52%), and wearing the respirator upside down (22%).

Factors associated with properly wearing an N-95 respirator included male gender, Caucasian race, and being a homeowner. Proper donning technique was also associated with having had previous experience with respirators, including owning them and undergoing fit testing.

The researchers concluded that educational efforts, particularly in the workplace, could increase the public's knowledge of proper N-95 respirator use and that labeling on the respirators (as opposed to separate instructions in the package) could promote proper donning technique.

"A unique opportunity exists to enhance protection of the public through interventions, such as educational campaigns, training sessions, and respirator design modifications, aimed at improving the public's ability to don a respirator correctly," the authors write.

The US Department of Health and Human Services (HHS) has stockpiled 20 million N-95 respirators for use during an influenza pandemic and plans to add 87 million more by the end of September, according to information on the HHS Web site.

Cummings KJ, Cox-Ganser J, Riggs, MA, et al. Respirator donning in post-hurricane New Orleans. Emerg Infect Dis 2007 May (early online release);13(5): [Full text]