Face masks and respirators: Personal respiratory
protective equipment for TB prevention
As per the CDC, there are three levels of TB
infection control in health-care settings.
The first level “administrative controls” should
minimize the number of areas where exposure to Mycobacterium
tuberculosis may occur.
The second level “environmental controls” should
reduce the concentration of airborne TB bacteria in areas where exposure
may occur.
The third level is the use of “personal respiratory
protective equipment” by persons entering the areas where exposure to
airborne TB bacteria may occur.
Personal respiratory protective equipment include
face masks and respirators.
· Face masks are cloth or
paper masks e.g. surgical masks, which prevent the spread of micro-organisms
from the user to other people by capturing large wet particles near the source
(mouth and nose), but it does not provide sufficient protection from inhaling
airborne infections.
· Respirators are special type
of closely-fitted mask with the capacity to filter particles 1 micron in size
to protect from inhaling infectious droplet nuclei.
The respirator has tiny pores, which block droplet
nuclei and forms an air tight seal around the entire edge. On the other hand, a
face mask has large pores and lacks air tight seal around edges and therefore
do not prevent leakage around the edge of the mask when the user inhales.
N95 masks are particulate respirators and filter
particles ≥1 micrometer in diameter with at least 95% efficiency given flow
rates up to 50 L/min. But, to be effective, N95 masks must fit the face with
less than 10% seal leakage. Adjustable nose clip helps in obtaining a secure
seal. All require fit-testing and must be adjusted to the face to provide the
intended effectiveness of filtering 95% of particles with mass median diameter
of 0.3 micrometers.
They are not designed for children or people with
facial hair. Because a proper fit cannot be achieved on children and people
with facial hair, so the N95 respirator may not provide full protection.
N95 respirators can be surgical or industrial
types. The ones used in hospitals are surgical ones and the one used in the
industry are industrial certified and are used in construction and other
industrial type jobs that expose workers to dust and small particles.
All respirators must be put on and taken off in an
area outside of the contaminated area. Putting a respirator on or taking it off
even for a few seconds in a contaminated area can expose the wearer to
significant levels of hazards.
All patients with cough (TB suspects on screening)
should be provided with simple mask at the reception of a hospital to cover
their mouths and noses. They should be advised about respiratory hygiene and
cough etiquettes. They should be instructed to cover their mouths and noses
when coughing or sneezing.
Use of a face mask does not protect health care
workers from TB.
Doctors and other health care workers should wear
N95 mask for TB prevention.
Dr KK Aggarwal
Padma
Shri Awardee
President Elect
Confederation of Medical Associations in Asia and Oceania (CMAAO)
Group
Editor-in-Chief IJCP Publications
President
Heart Care Foundation of India
Past National President
IMA
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