Metered Dose Inhalers for Asthma

What is a hydrofluoroalkane inhaler with a spacer?

Inhaled asthma medications are often delivered by using a device called an hydrofluoroalkane inhaler or HFA. The HFA used to be called a metered dose inhaler or MDI. The inhaler is a small aerosol canister in a plastic holder that delivers a puff of medication to the lungs.

To help make it easier for your child to use the HFA and ensure the medication gets into the lungs, your child may use a spacer chamber (with or without a mask) with the inhaler. The purpose of the spacer chamber is to hold the medication released from the HFA so that your child has the time to more effectively inhale the medication. These devices are recommended for all children who have difficulty coordinating breathing and the use of the inhaler correctly (particularly children less than five to six years old).

The contents of an HFA are under pressure and are released quickly, making it difficult to coordinate inhalation of the particles. The spacer chamber suspends these particles until your child breathes in, reducing the amount of coordination required to inhale the particles, thus easing the delivery of medication into the lungs. Adults should also use a spacer chamber, especially if they have problems using the HFA. Spacer chambers can also reduce the deposition of particles in your mouth or tongue and therefore may reduce side effects from medications. Spacer chambers should not be used with a dry powder inhaler (DPI).


How Does my Child Use a Spacer Device?

Directions for using the metered dose inhaler with a spacer chamber and a device like a mask are given below. Read these instructions before using the device. Your asthma care team will also teach you and your child how to use these devices.

To use the HFA and spacer (with or without a spacer device ):

  1. Remove the caps from the HFA in haler and spacer chamber( add spacer device if needed).
  2. Shake the canister well.
  3. Insert the HFA into the back end of the spacer chamber.
  4. If there is a spacer device such as a mask, place it over your child's nose and mouth, making sure there is a good seal. If there is just a mouth piece, the tip should go between the teeth and lips wrapped tightly around to make a good seal.
  5. Press down firmly on the canister to release one puff of the medication into the spacer chamber.
  6. Hold the mask firmly in place while your child takes at least six breaths. If your child is using a spacer chamber with mouth piece, after inhaling the medication, he should hold his breath for 5-10 seconds then breathe out slowly.
  7. Wait one minute.
  8. Repeat steps two through seven for each puff of medication ordered.
  9. When treatment is complete, remove the HFA from the space chamber.
  10. If using this device with an HFA that contains a steroid, wipe your child's face with soap and water after use to remove any medication. If possible, also rinse your child's mouth with water.

There are specialized valved-holding spacers that have a one-way valve that allows the drug to be inhaled but also helps holds the medication in the chamber during exhalation. These devices can be fitted with a mouthpiece or a facemask to be used in infants and young children.



How Do I Care for a Hydrofluoroalkane Inhaler With a Spacer ?

Clean the spacer chamber every other day. If you are not using it often, you may only need to clean it once a week. Let it air dry, and store it in a clean, dry place when you're not using it.


How Do I Know When a Hydrofluoroalkane Inhaler Is Empty?

The number of puffs contained in your child's metered dose inhaler is printed on the side of the canister. After your child has used that number of puffs, you must discard the inhaler even if it continues to spray. Keep track of how many puffs your child has used. Many brands of HFA also have digital counters build into them that show how many puffs are left.

If your child uses an HFA every day to control his or her asthma symptoms, you can determine how long it will last by dividing the total number of puffs in the HFA by the total puffs your child uses every day. For example, if your child's HFA has 200 puffs and he uses four puffs per day, divide 200 by four. In this case, your child's HFA would last 50 days. Using a calendar, count forward that many days to determine when to discard your child's HFA and begin using a new one.

If your child uses an inhaler only when he needs to, you must keep track of how many times your child sprays the inhaler. If you prefer, you can obtain a device that has a counter to count down the number of puffs each time your child presses the inhaler. Ask your child's doctor for more information on these devices. In general it is important to be aware of how many doses remain in the HFA. Even when the medication is depleted, the HFA can still release a spray of propellant that can be mistaken for a spray of medicine.

WebMD Medical Reference Reviewed by Dan Brennan, MD on July 19, 2019



National Heart Lung and Blood Institute: "Asthma."

American Lung Association: "Learning More About Asthma."

American Association for Respiratory Care: "A Patient's Guide to Aerosol Drug Delivery."

Mayo Clinic: "Asthma inhalers: Which one's right for you?"

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