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2.3.2 What is a spacer? What is a holding chamber?


This article is from the Asthma FAQ, by Patricia Wrean and Marie Goldenberg mwg@radix.net with numerous contributions by others.

2.3.2 What is a spacer? What is a holding chamber?

Metered dose inhalers (MDIs) for asthma medications typically
consist of a metal aerosol canister (containing the medication and
a propellant) in a plastic sleeve with a mouthpiece. The patient
inhales one or more metered doses of a medication through the
mouthpiece. Most people find it difficult (at least initially) to
time the spraying of an MDI and the inhalation of the medicine:
the patient must exhale fully and inhale and release the metered
dose just at the beginning of the inhalation so as to draw the
medication as fully and deeply into the lungs as possible.

All too often the puffs are mis-timed and only make it part of the
way into the airways, and some of the medication is invariably
deposited into the mouth and on the back of the throat instead of
into their lungs. In addition to being less effective, this can
lead to other side effects (e.g., for inhaled steroids, an
increased potential for thrush, an oral fungal infection described
in section 2.3.3).

Several devices have become available that address these
difficulties to varying degrees. The devices are generally
referred to as "spacers" since they place additional space between
the patient and the MDI. The medication is sprayed into the spacer
instead of the mouth. As the patient inhales, the column of
medication passes through the mouth and throat relatively quickly,
leaving little opportunity for the medication to be deposited in
the mouth or throat. This is a more efficient means of delivering
the medication to the airways where it's most needed.

The simplest kind of spacer is basically a tube. The patient
sprays the medication in one end of the tube and inhales it out
the other end. Azmacort has a simple spacer attached to it. A
cardboard tube from the core of a roll of bathroom tissue can be
used as a spacer (as long as it's clean, lint-free and germ-free).
While a simple spacer reduces the amount of medication that gets
deposited in the mouth and throat, it still requires you to
carefully time your inhalation with the discharge of the
medication to minimize the amount of the medication that escapes
from the spacer.

A "holding chamber" is a more sophisticated device. It is a sealed
chamber (once the inhaler is inserted) that traps and holds the
medication, allowing the patient to spray the medication into the
chamber and take a few seconds to inhale the medication. Since
the medication is temporarily suspended in the holding chamber,
the timing of the inhalation is not nearly as critical as with
simple spacers or no spacer. AeroChamber is a brand of holding
chamber. It's a plastic tube with a mouthpiece on one end and a
place to insert the MDI on the other. The mouthpiece has a
one-way valve built in that temporarily contains the sprayed
medication, and also allows the patient to exhale without
displacing the medication in the chamber (as without a spacer, the
patient should exhale as completely as possible before taking in
any medication, so that the medication can be inhaled as deeply as

In addition to improving the timing of the inhalation, a holding
chamber makes it possible to take in the medication more slowly
than is possible without a spacer or with a simple spacer. This
is important for the symptomatic patient, since rapid inhalation
of the medication is more likely to trigger coughing and cause the
patient to lose the medication before it has had a chance to be

Some spacers are clear so that you can see the puff of medicine,
and so that you can see when the medication is building up on the
inside, indicating that the spacer needs cleaning.

Spacers and holding chambers need periodic cleaning; clean
carefully, following the manufacturer's instructions so as not to
damage any delicate internal parts or allow molds or other
contaminants to be introduced.

There are special holding chambers for younger children. There's
a pediatric Aerochamber that has a mask built in; the child
breathes normally for a few seconds with the mask held over
his/her mouth and nose. This is typically used when a nebulizer
is not available or not required, and for medications that are not
available in a nebulized form, such as Beclovent or Vanceril.

There is also a device for children (and for people that have
trouble holding their breath) called an InspirEase. It's kind
of like a plastic bellows or balloon with a plastic mouthpiece.
The patient inflates it, the medicine is sprayed into it, and the
patient inhales, holds his/her breath for the count of 5 (or
whatever the doctor recommends), exhales into the device, and then
repeats. Some patients are instructed to breath slowly in and out
several times instead of holding their breath. The InspirEase
really helpful for younger children who yet aware of the
difference between breathing in and breathing out or don't yet
know how to hold their breath or breathe evenly and slowly. It
gives them immediate physical feedback, and it also has a whistle
built in to tell them when they're breathing too fast (although
they seem to like making it whistle, so it's positive
reinforcement for something that they shouldn't be doing). As the
child grows, the Inspirease becomes less effective, since it has a
limited capacity, although I've been told that it is available in
different capacities.

Knowing the difference between a simple spacer and a holding
chamber can help you use each in its proper way. If you use both a
holding chamber *and* a simple spacer (e.g., a holding chamber for
your Ventolin and the simple spacer attached to your Azmacort),
you need to remember which you're using and adjust your style

Spacers and holding chambers are sometimes provided by some HMOs
and covered by some insurers.

Contributed by: Mark Feblowitz mfeblowitz@GTE.com

[Maintainer's note: Some spacers seem to be prescription only,
while others are not. Whether you need a prescription also
seems to vary from state to state in the US. When in doubt,
ask. As to why you would need a prescription (i.e. how
could you abuse this simple plastic tube?), the nurses at
National Jewish were as puzzled as I was.]


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next page: 2.3.3 What is "thrush mouth" and how can I avoid it?