TABLE 2.

Advantages and disadvantages of a spacer/valved holding chamber (VHC)

Advantages

Slows down the aerosol cloud as it emerges from the pMDI

Reduces impact of hand–breath (activation–inhalation) coordination problems

Longer propellant evaporation time reduces particle size (increases respirable fine-particle fraction) and improves lung deposition

Filters out larger aerosol particles

Reduces oropharyngeal impaction/deposition and local side-effects (inhaled corticosteroids)

Reduces fraction of swallowed drug, gastrointestinal absorption, systemic bioavailability and thus extrapulmonary unwanted effects (β-adrenergic agonists)

VHCs can be used with tidal breathing, administered by a care giver

For the very young (using a face mask) and any patient where coordination is a challenge

During acute exacerbations (replacing nebulisers)

Disadvantages

Require regular cleaning

Large-volume spacer/VHC devices are more bulky and less portable

Electrostatic charge may reduce the respirable aerosol fraction

More expensive (but may save medication)

pMDI: pressurised, metered-dose inhaler.