Respirators are specially designed masks that act as a personal protective measure to prevent the inhalation of bacilli. Respirators should be used by all staff and carers in areas where the risk of TB transmission is high:
– Smear-positive inpatient units
– Diagnosis department
– Culture/DST and sputum smear preparation area (laboratory)
– Sputum collection area
– Radiology department
The WHO recommends21 the use of:
– The United States Centre for Disease Control and Prevention/National Institute for Occupational Safety and Health certified N95, with filtering efficiency > 95% if challenged with 0.3μ particles.
– The CE-certified filtering facepiece class 2 EN 149:2001 (FFP2, filtering efficiency 94%, if challenged with 0.3μ particles)
Note: paper or cloth surgical masks do not protect a person against TB.
20.2 Instructions for use
Respirators are for personal use. The same respirator cannot be shared between other staff members, or between other carers.
The respirator should be put before entering the room and removed after exiting the room.
Respirators must be worn covering the nose, the mouth and the chin and providing a tight seal around the edge. Everytime that a respirator is put on, a seal check has to be performed:
– Fully open the respirator and slightly bend the nose wire to form a curve.
– Separate the two elastic straps and position the respirator under the chin.
– Stretch the two straps over the head, place the first strap at neck-height and the second strap across the top of the head.
– Model the nose wire around the bridge of the nose and secure the edges until you achieve a perfect fit.
– Check for leaks by covering the respirator with both hands and forcefully inhaling and exhaling several times. The respirator should collapse when inhaling and expand when exhaling and no air leak between the face and the respirator should be detected. Otherwise, straps should be readjusted and/or the respirator repositioned until is sealed properly.
Different factors may not allow proper sealing of respirators to the face: respirators size and model; respirator wearer’s facial features, including beard and facial hair; headscarves, etc.
There is limited evidence on the acceptable length of time a respirator can be worn with maintained efficiency. The filter materials remain functional for weeks or months however, the fitting may decrease with frequent wearing.
A respirator extensively used should be discarded after 7 days. If it is only used a few hours 2 to 3 times per week for example, it can be reused for several weeks6. During this period, the staff can reuse their respirator as long as they are not wet or damaged and provided they do not have loosened straps. Each staff should keep his/her respirator in the pocket of his/her personal gown without creasing it. If the filter material is damaged or the mask has loose straps, the respirator should be immediately discarded.
Note: TB bacillus is trapped in the filter of a mask, and will not be released with shaking or other physical movements of the mask6.
Store in a dry, well ventilated place. Respirators should not be crushed during storage.
Respirators are disposed as “soft waste” and do not need to be disinfected before being discarded.
20.5 Fit testing
Proper fit of a respirator is critical to ensure respiratory protection. Therefore, all staff members who will potentially be exposed to M. tuberculosis should perform, before they are required to wear any respirator, a “fit testing” to determine if the respirators being used in the program fit them properly.
At least two models of respirators should be available. If a worker is not able to be fitted with one model, the other one may be used instead.
Testing is performed using a fit testing kit. This kit contains all supplies and instructions needed to perform the test. See MSF Medical catalogue, volume 2B.
Fit testing kit