Abstract
Our aim was to synthesize the published literature on factors that potentially affect the delivery of bronchodilators using valved holding chambers (VHC) in preschool children. We also aimed to identify those attributes that are not yet incorporated or clearly stated in the guidelines and those topics that are still lacking sufficient data. There is strong evidence supporting several recommendations in current guidelines. Based on present knowledge, bronchodilators should be delivered by VHC administering each puff separately. Face mask should be omitted as soon as the child can hold the mouthpiece of the VHC tightly between the lips and teeth. Based on the review, we suggest adding a specific note to current guidelines about the effect of chamber volume and the impact of co-operation during drug administration. Calming the child and securing a tight face-to-mask seal is critical for successful drug delivery. There is not enough evidence to make specific recommendations on the most reliable VHC and face mask for children. There is an urgent need for studies that evaluate and compare the effectiveness of VHCs in various clinical settings in wide age-groups and respiratory patterns. In addition, there is insufficient data on ideal chamber volume, material, and effective antistatic treatment. What is Known: • Valved holding chambers (VHC) should not be considered interchangeable when used with pressurized metered dose inhalers (pMDI). • Drug delivery is influenced by VHC volume, aerodynamic and electrostatic properties; mask fit; respiratory pattern and co-operation during inhalation; and the number of puffs actuated. What is New: • The impact of co-operation, VHC volume, and good mask-to-face fit during drug inhalation is not stressed enough in the guidelines. • Studies are urgently needed to evaluate the effectiveness of different VHCs in various clinical settings focusing on VHC electrostatic properties, respiratory patters, face masks, and ideal pMDI+VHC combinations.