You think you’re pretty good at using your metered-dose inhaler (MDI), 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?’
An MDI is not enough…
You need a holding chamber or spacer!
Inhalation accessory devices (IADs) generally fall into two categories: valved holding chambers (VHCs) and spacers. These devices improve direction and deposition of medication delivered by MDIs.
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 MDI 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 VHCs 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 valved 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 MDI. 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 MDI actuation.
Valved holding chambers are fitted with a universal rubber end piece that accommodates the MDI without having to remove the canister from the boot. This important feature allows the patient to use the MDI 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 MDI, whereas others require removal of the MDI 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 valved holding chamber:
- Always read and follow the manufacturer’s instructions.
- Clean the VHC according to the manufacturer’s instructions or when the unit becomes cloudy or filmy inside. Time cleaning so that the unit has a chance to air-dry completely before the next dose is needed.
- Check the insertion port to make certain it is clean and free of any small particles before attaching the MDI.
- Replace disposable parts as recommended to avoid bacterial growth.
- If your prescription calls for two puffs of medication, shake the MDI (if product instructions specify), actuate the inhaler, inhale slowly and deeply, hold your breath a few seconds, exhale, and repeat the entire process (including shaking the MDI) for the second puff. Never spray two puffs of medication into a holding chamber at one time. Ask your physician or pharmacist about how much time to allow between puffs of medications.
- Use a permanent marker to note the purchase date of the holding chamber on the side of the device. Discard your unit when advised in the package instructions or if the unit fails to operate as expected.
First published: Allergy & Asthma Health Consumer Guide 2002
Reviewed: March 2009
This article first appeared in Allergy & Asthma Today, AANMA’s award-winning magazine for people with asthma, allergies and related respiratory conditions. Click here to subscribe to the magazine.