Thank you for your inquiry.
Spacer devices are not needed in all patients with asthma, but clearly are of benefit in any patient who finds it difficult to master the correct technique for inhalation of medications from a metered-dose inhaler. Many children, therefore, are clearly candidates for a spacer. You are correct in that the use of a spacer, in such patients, can enhance the delivery of drug to the lung, and also can diminish potential side effects from local deposition in the upper airway.
Here is a link to an excellent reference for you from Medscape. It should be available to you free of charge online. It contains a number of references to the literature that document the value of the use of spacers in the appropriate patient population.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.