You think you’re pretty good at using your pressurized metered dose inhaler (pMDI), right? But…

If you feel it touch your tongue,
Splash your cheeks or spray your gums,
If you’re a kid and on the go,
Or not so young, but in the know,
If you wonder, ‘Did I get that puff?’
A pMDI is not enough…

You need a holding chamber or spacer!

Inhalation accessory devices (IADs) generally fall into two categories: holding chambers and spacers. These devices improve direction and deposition of medication delivered by pMDIs.

Inhaled medications target inflamed and congested airways directly, but they are only as effective as the ability of the user to position and depress the pMDI a split second after beginning a slow, deep inhalation. Sounds easy, but when the dose of medication leaves the inhaler at about 60 miles an hour, a lot of medication can be lost to the air, top of the tongue, sides of the cheeks, or back of the throat and swallowed before making it to the airways.

All holding chambers are spacers, but spacers are never holding chambers. It’s a distinction that may be overlooked even by those people who’ve used the devices!

Both spacers and holding chambers extend the mouthpiece of the inhaler and direct the cloud of medication toward the mouth, reducing the amount of medication released into the air. However, a holding chamber directs, traps, and suspends particles of medication long enough to be inhaled over a period of a few seconds, while a spacer is simply directional.

The biggest difference between the two is timing and technology. When using a spacer, you must still coordinate your breath to occur slightly before actuating the pMDI. It’s also good advice when using the holding chamber but not as critical; a one-way valve traps and suspends particles of medication long enough to be inhaled slowly and deeply for several seconds after pMDI actuation.

There are a wide range of holding chamber and spacer products from which to choose. Some holding chambers are fitted with a universal rubber end piece that accommodates all pMDIs without having to remove the canister from the boot. This important feature allows the patient to use the pMDI exactly as the Food and Drug Administration approved it. Holding chambers are available for use with and without masks sized for infants to adults.

Spacers or extenders are sometimes built into the pMDI, whereas others require removal of the pMDI canister from the manufacturer’s boot and insertion in a special port on the IAD, an action that may or may not affect product performance.

Follow these tips when using your IAD:

1. Always read and follow the manufacturer’s instructions before using the IAD.
   
   
2. Clean the IAD according to the manufacturer’s instructions or when the unit becomes cloudy or filmy inside. Time cleaning so that the IAD has a chance to air-dry completely before the next dose is needed.
   
   
3. On those IAD units that utilize the pMDI canister (no boot) only, check the insertion port to make certain it is clean and free of any small particles before attaching the delicate pMDI stem.
   
   
4. Replace disposable parts as recommended to avoid bacterial growth.
   
   
5. Always shake the pMDI before using.
   
   
6. If your prescription calls for two puffs of medication, shake the pMDI, inhaling slowly and deeply while actuating the inhaler, hold your breath a few seconds, exhale, and repeat the entire process (including shaking the pMDI) for the second puff. Never spray two puffs of medication into a holding chamber or spacer at one time. Ask your physician or pharmacist about how much time to allow between puffs of medications.
   
   
7. Some pMDIs cannot be used in the same IAD that has been used with another pMDI because the exit port may become clogged. This is only true of those IADs that require the canister to be removed from the plastic boot and inserted into the IAD.
   
   
8. Use a permanent marker to note the purchase date of the IAD on the side of the device. Discard your unit when advised in the package instructions or if the unit fails to operate as expected.
   
   

Reprinted from Allergy & Asthma Health Consumer Guide 2002. Medical editors for this article: Martha Hogan, M.D., Neil MacIntyre, M.D., Michael Mellon, M.D.