(MDI); the mouthpiece slots into the back of the spacer. To use an inhaler without a spacer requires coordinating several actions in a set order (pressing down on the inhaler, breathing in deeply as soon as the medication is released, holding your breath, exhaling), and not everyone is able to master this sequence. Use of a spacer, particularly a valved holding chamber, avoids such timing issues. Valved holding chambers are particularly useful for children, people with severe
shortness of breath, and those with cognitive impairment. After removing the MDI's cap, the MDI mouthpiece is inserted into the back of the spacer. The front part of the chamber is closed off by either a mouthpiece or a mask that covers the mouth and nose. To administer the medication, the MDI is depressed once, resulting in the release of one dose of medication. The medication from the MDI is then suspended in the spacer's chamber while the person inhales the aerosolized medication by breathing in and out. The exhaled breath exits the device through the
valves rather than entering the chamber. Some spacers are equipped with a whistle, which sounds if the person is inhaling too quickly. Spacers slow down the speed of the
aerosol coming from the inhaler, meaning that less of the
asthma drug impacts on the back of the mouth and somewhat more may get into the lungs. In the case of
corticosteroids, less residue in the mouth reduces the risk of developing
oral candidiasis, a yeast infection. Rinsing the mouth after application of inhaled steroids has a similar effect. Whereas people with asthma can keep an MDI close-by at all times, the bulkiness of spacers can limit their use outside the home. Some research suggests that homemade spacers, using plastic bottles, may be as effective as commercially made versions, but homemade versions may have more variability. ==References==