Airborne Pathogens: Elusive and Dangerous

The main concern about fit testing is that even when done properly and accurately, the HCW is only assured of a good fit for the masks that were used during the testing. Once they leave the test area, putting on another mask is another fitting episode. Is it done by the individual the same way each time, under the pressing conditions of the infected patient care regime? If not, disaster can happen as it did in Toronto during the SARS epidemic.

Also, masks, N95 and surgical, can not be fitted to HCWs with facial hair and other variables in facial shape, such as scars, large weight gain or loss, etc.

Even with a secure fit, the inherent filtering efficiency is less than PAPRs.

FDA (U.S. Food and Drug Administration) does not test surgical masks as they do respirators. Surgical masks are rated by the manufacture, and their reported particle filtration efficiencies, e.g., >95 percent, may be considerably higher values than what would be obtained using NIOSH N-95 test methods, e.g., as low as 70 percent.

Similarly, the maximum, ideal filtration efficiency of an N95 respirator is only guaranteed to be 95 percent. That means that with an excellent fit, 5 percent of the contaminant has to be expected to get through.

PAPRs (helmet-style respirators) use inherently higher efficiency filters than either surgical masks or N95 respirators. And, they are positive pressure respirator systems so they do not require fit testing. Also, they are reusable and are used interchangeably between HCWs, with appropriate decontamination between uses.

Masks and N95s are negative pressure devices. When the user inhales they create negative pressure within the mask that will suck in contaminated air anywhere there is an incomplete seal with their face. This is why a perfect seal, or fit, is so crucial.

PAPRs on the other hand, are positive pressure devices. For example, the MAXAIR System blower pulls the contaminated air through high efficiency filters, with from 99.97 percent to 99.997 percent filtering efficiency.

Now only .03 percent to .003 percent of the contaminant may get through. That is at least 150 to 1,500 times less than a mask.

The MAXAIR blower pulls in air, filters it, and passes it gently down in front of the face at a user selectable 6 CFM to 9 CFM. This provides sufficient air for all working conditions, and it provides an automatic cooling effect to the user.

More importantly, the high volume of air flow creates a positive pressure within the helmet so that the HCW can not pull in contaminated air from around the facial seal. This is the reason PAPRs do not require fit testing.

Another benefit of the PAPR air flow control is that is makes breathing as natural as if the HCW wasn’t wearing a respirator at all. This is not the case with masks as they present resistance to breathing.

Just as a leading healthcare institution published in 2005, you can achieve both better respiratory protection and a long term cost advantage with a non conventional PAPR solution such as MAXAIR.