A spacer device is a large plastic container, usually in two halves that click together. At one end is a mouthpiece and at the other end is a hole for inserting the mouthpiece of an inhaler (also known as a metered-dose inhaler or MDI).
Let's face it. Many people using metered dose inhalers (MDIs) find them hard to use. This is because it can be difficult to coordinate breathing in and pressing the inhaler at the same time. The spacer is designed to make the MDI easier to use, thus delivering more medicine directly into the lungs where it is needed. This makes your asthma medication more effective and reduces the side effects that may occur from inhaling the medicine into the mouth or throat.
So why use a spacer? They serve two functions:
- to overcome difficulties in coordinating the timing of inhaler activation and inhalation.
- to slow down the speed of delivery of the aerosol into the mouth, so that less of the drug impacts in the throat. This reduces side effects from the drug coming in contact with the tissues of the throat, including pain and irritation.
Spacers are only partly effective in overcoming poor timing in the use of inhalers. If the inhaler is pressed during exhalation, instead of the beginning of inhalation, at least 50% of the dose is lost, even with the better-designed spacers (e.g., Aerochamber, Optichamber, Medispacer).
How does your doctor pick a spacer for you? Usually, your doctor will discuss with you any challenges or issues that you are having with your inhaler, and then make a selection based on what will best help you.
Spacers can have a variety of features including:
- A valved chamber with exhalation ports is useful to prevent exhalation into the chamber and it allows inhalation of any drug remaining after the first breath in.
- A flow rate signal helps to warn the user that the inhalation is too fast.
- Universal inhaler adapters conform to the mouthpiece of any metered dose inhaler, whereas some spacers have rigid adapters that fit only one type of inhaler mouthpiece.
The dose from your inhaler is sprayed into the spacer, from where it can be inhaled, without needing to coordinate breathing and pushing down the inhaler canister. It is particularly useful for babies and small children. Paediatric spacers usually have a small mask that fits onto the mouthpiece of the spacer and is placed over the child's nose and mouth.