A quick message to my friends in the northern hemisphere.

Those of you working in the hospital environments are about to get a lot more familiar with the disposable high filtration masks known as P2 or N95 masks.
One thing I noticed from my own experience during our winter H1N1 influenza pandemic is that the particular brand of P2 masks that our hospital supplied did not fit me very well.

On a few occasions I found myself looking after some pretty sick patients with confirmed or highly suspected H1N1 influenza who were requiring ventilatory support.
I was wearing full protective equipment, but no matter how I re-positioned the elastic straps behind my head, or tweeked or twiddled my P2 mask, my glasses would continue to fog up with my breathing. Obviously there was some air leak around the bridge of my nose making the mask less than effective.
And constantly bumping into things wasn’t much help either.

Fit check:

Each of us has a unique facial structure with its own characteristic shape, and size and its own topographical nooks and crannies.
And any one particular type of P2 mask may not provide an adequate protection for your individual mush¹.

Every time you don a P2 mask you should perform a self-fit check to ensure the mask is fitting correctly.
After compressing the mask to seal across the bridge of the nose, and ‘snugging’ the mask across the cheeks and under the chin, you should then gently inhale. The mask should draw in slightly or collapse into the face. Like a pucker.
With gentle exhalation the mask should re-expand to its previous shape.
Do it quickly, and you just look silly.

But the fit check is not enough.

Fit test:

The Australian/New Zealand standard “Selection Use and Maintenance of Respiratory Protective Devices”, also advises employers to provide a fit testing process to ensure the particular brand of mask provides you with a sealed protection.

There are two fit testing methods:

The qualitative or Hood Method: a hood is placed over the operators head and a concentrated solution is atomized into the hood via an access window.
The solution is sprayed into the hood in aliquots until the operator can taste it. The test is then repeated with the operator wearing the P2 mask and the results are compared.

The quantitative or Instrument Method: uses an instrument that measures the concentration of microscopic particles found behind the respirator mask and then compares this to the amount in ambient air. From this it calculates a fit factor which must be equal or greater than 100 to pass the test.

To make sure the fit is good, each of the tests is done with the operator performing activities such as deep breathing, moving their head around, grimacing, bending forward etc.

These tests can be time consuming and expensive (particularly the quantitative method).
But if your hospital is serious about providing quality protection for its staff, and potentially prevent a high infection rate amongst them, fit checks and fit tests must be mandatory.

These masks are no fashion accessories, and just because you have one on your face does not mean you are protected.
Is your hospital providing education and training in fit checks and fit tests?

[More posts on the H1N1 influenza.]

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