Train The Trainer

Firstly, it is important legally that you are able to demonstrate competence of those performing face fit tests. Simply purchasing a kit and watching an instructional DVD would be deemed wholly inadequate by inspectors or lawyers.

Ok, now we have sorted out that minor legality lets discuss how a face fit test kit is prepared for use.

There are several manufacturers of qualitative test kits around but they are all based on the same premise; namely they contain a pair of solutions that are either Bitter or Sweet in taste, the kit will also contain a hood that encapsulates the head of the person being tested and a pair of nebulisers that fill the hood with a leak-detecting aerosol that the person being tested either tastes (a fail) or doesn’t (a pass).

The first thing we want to do is ensure the kit is in an operational condition, identify the flavour of the kit and confirm you have both a Sensitivity solution and a Test solution in that flavour.

We want to check there’s sufficient solution to undertake a test and that the solutions are in-date. A red-flag for replacing the solutions would be a significant amount of crystallised deposits around the neck of the bottle indicating that water has evaporated from the bottles and the concentration of them has altered.

Secondly, we turn our attention to the nebulisers and identify which we will put the sensitivity solution into and which we will add the test solution in. In some kits they don’t have markings on the nebulisers to identify which solution goes in which. In this case, label one of the nebulisers so you know which solution you have in them.

Like we checked the bottles we need to visually inspect the outside and inside of both nebulisers looking for any evidence of crystallised deposits indicating improper cleaning after their last use. This is vitally important as even a tiny deposit lodged in the inner workers can render the nebulisers inoperative or inefficient meaning we don’t get the dose delivery required from them.

The aerator that lifts off of the air exit hole inside the nebuliser must be pushed down as low as possible for it to be able to draw the liquid up effectively.

We can now add the Sensitivity solution and Test solution to the respective nebulisers. If you are filling from bottles fill the nebuliser to just below the black sealing ring you can see located in the threaded section that joins the top and the bottom, this is about 4cc (less than a teaspoon of solution) so go steady.

If you are filling from single use ampules you will usually need to use two ampules per nebuliser initially to achieve a working level that ensures the nebulisers will work effectively. It is important to use the protective cardboard sleeve when breaking the glass inside an ampule to prevent injury. Also, break the ampule by squeezing and NOT BENDING. Glass stuck in your fingers is not pleasant.

Hold the ampules with the pointy end up to break then invert and empty into the nebuliser by squeezing through the in-built filter, ensure you fully empty the ampules. Whether using bottles or ampules it is always easier to fill the nebulisers when they are assembled, do this by pouring down through the top hole.

Once filled, hold the nebuliser up to a light and squeeze the bulb firmly so all the air within it is exhausted, this should generate an aerosol that spreads ~30cm from the exit nozzle. Poor spray is likely down to bad technique, a blockage or the lower vent plug having not been removed.

Once happy the nebulisers are working gently replace the vent caps and store vertically to prevent leakage.

If it is the first time using the testing kit you will need to remove a paper film from the vision panel on the hood.

The 3M testing kits have a shoulder collar with a finger hole on the front and a hood that attaches to this. Putting the two together is tricky and is best done by laying the hood flat on a table with the vision panel facing up. Next, take the collar with the finger hole pointing up and place the rim of the rear of the collar 1” inside the hood, compress the collar down in the middle so you can now lift the front of the hood over the rim and release. This should hold it sufficiently in place.

Moldex and some other test kits use a pull chord to close the bottom of the hood around the neck! Place the hood over the subjects head and pull the hood tight against the back of the subjects neck, whilst asking the subject to look upwards hold both chords tight in one hand and slide your other hand along the chords drawing the bottom of the hood closed, stop just before their throat!

A simple quick release knot is preferable to facilitate a speedy exit if necessary. The kit is now ready to use.