Why use a valved holding chamber?
Clinical studies have shown that by adding a valved holding chamber (VHC) to a pressurised metered dose inhaler (pMDI), drug delivery to the lungs can be improved by 40% to 60% 1 For this reason, you should always use a VHC in conjunction with your pMDI for both your daily preventer medication and when using your reliever in an emergency.
Using a VHC can:
- Enable more medication to be delivered to your lungs making drug delivery more effective.
- Reduce side effects from inhaled steroids in preventer medications because less medication is deposited in your mouth and throat.
- Make dosing easier as you don’t need to coordinate pressing your pMDI and breathing in at the same time.
Who should use a VHC?
It is recommended that people of all ages with asthma use a VHC with their pMDI. Young children are advised to use a face mask with their VHC as they have difficulty sealing their lips around the mouthpiece. Depending on the child’s ability to seal their lips effectively, they can be introduced to the mouthpiece of the VHC at around the age of two.
How do you use a VHC?
- Remove protective cap from the pMDI, shake the pMDI well and insert it firmly into the base of the VHC.
- Seal lips around the mouthpiece (or attach face mask to mouthpiece and place mask over child’s mouth and nose).
- Breathe out gently.
- Press the pMDI once to release a dose of medicine into the VHC. Do not remove the pMDI.
- Breath in and out about 4 times keeping lips sealed around the mouthpiece (or the child’s mask in position).
- You should only release one dose of medication into your VHC at a time. Releasing more than one dose can cause medication to stick together and drop to the bottom of the VHC before you can breathe in. If a second dose is needed, shake the pMDI again and repeat steps 2-5. You can shake the pMDI while it is still attached to the VHC.
How do you clean a VHC?
A VHC should be washed at least once a month but can be washed more if needed.
- Take the VHC apart as per manufacturer’s instructions and wash in clean, warm water with dishwashing detergent.
- Allow to air dry – do not rinse or wipe dry. The detergent residue helps to prevent the creation of static electricity inside the VHC, which can lead to medication sticking to the sides of the VHC.
VHCs should be replaced every 12 months as tiny scratches and abrasions can reduce its effectiveness. Replace your VHC immediately if it is damaged.
1STEPHEN P NEWMAN, ANN B MILLAR, TIMOTHY R LENNARD-JONES, FOLKE MOREN, STEWART W CLARKE Improvement of pressurised aerosol deposition with Nebuhaler spacer device Thorax 1984;39:935-941