For years, patients have been trained using inhaler placebos. But this solution is far from perfect. A recent study showed that a lack of placebo availability can have a substantial, negative impact on patient training. Selection of inhalers also depend on availabity of the placebo devices to train patients on correct use of medication.

Check this out: http://www.educationforhealth.org/data/files/resources/InhalerDeviceSelectionPoster.pdf