Inhalation technique and variables associated with misuse of conventional metered-dose inhalers and newer dry powder inhalers in experienced adults.

Background: Pressurized metered-dose inhalers (pMDIs) are often poorly used, but little information is available concerning use of the newer dry powder inhalers (DPIs).

Objective: To estimate the inhalation technique and variables associated with the misuse of pMDIs and newer DPIs in clinical practice.

Methods: A multicenter, observational survey was used to evaluate the inhalation technique in 1,404 experienced outpatients aged 15 to 88 years affected mostly by asthma (47%) and chronic obstructive pulmonary disease (39%). A total of 1,056 patients were using pMDIs, 190 in conjunction with a large volume spacer (LVS); regarding DPIs, 230 patients were using the Aerolizer Inhaler, 524 were using the Turbuhaler, and 475 were using the Diskus. In each center, a trained observer recorded patients' inhalation techniques for each inhaler used against a standardized step-by-step checklist.

Results: Twenty-four percent and 3% of patients used pMDIs poorly, alone or with an add-on LVS, respectively. Failure to correctly perform essential steps for reliable lung delivery with the Aerolizer Inhaler, Turbuhaler, and Diskus was found in 17%, 23%, and 24% of patients, respectively. There was no difference in most variables correlated with poor inhalation between patients using pMDIs and those using DPIs.

Conclusions: The use of DPIs is associated with a similar percentage of inadequate inhalation technique as the use of pMDIs in clinical practice. The addition of an LVS to a pMDI and education from health care personnel, rather than simply changing inhalers, represent the best strategies for minimizing poor inhalation technique.